PH6004 – FINAL STUDY GUIDE
➢ 1. Toxicology and Risk Assessment
• Define key terms and concepts (e.g., NOAEL/LOAEL, LD50, RfD, slope factor)
➢ NOAEL: no observable adverse effect level; HIGHEST dose administered → that does NOT produce an adverse effect
➢ LOAEL: lowest observable adverse effect level; LOWEST dose administered → that DOES produce an adverse effect
➢ LD50: lethal dose 50; the number of organisms needed to cause death in 50% of the infected hosts
➢ ID50: infectious dose 50; the number of organisms needed to cause an infection in 50% of the hosts
➢ TD50: the toxic dose at which 50% of individuals show TOXICITY! ➢
➢ LC50: For AIR, the lethal CONCENTRATION where 50% of individuals die! ➢
➢ TC50: For AIR, the lethal concentration where 50% of individuals show TOXICITY!
➢ RfD: reference dose; the value of the dose that is assumed to be SAFE for the human population
➢ * RfD (The reference dose is less than )< NOAEL (the no observable adverse effect LEVEL is less than) < LOAEL (the lowest observable adverse effect LEVEL) We also discuss several other topics like ncs study guide
➢ slope factor: you can look up slope factors for different cancers or carcinogens ➢
➢ *** To compute cancer risk = Dose x Slope Factor *** (* You can look up slope factors for different cancers or carcinogens)
➢ MTD: Maximally Tolerated Dose (before they die); In chronic cases (such as cancer) you use the MTD --> you want all your subjects to live their full lifetime. ➢
➢ De Minimus Risk: a level of risk that is too small to be concerned with..also known as “virtually safe”..
• Explain how toxic agents are identified and characterized— differentiate between acute and chronic toxicity and tests for each
➢ Acute toxicity: sudden/rapid onset of toxic effect!; minutes, hours, or days (e.g., irritants, chlorine gas) * Acute does NOT mean severe!! We also discuss several other topics like inr 2002
➢ Chronic toxicity: toxic effect after long periods of exposure, usually many months or years (e.g., cancer, liver damage, lung fibrosis)
➢ In Vivo testing: in whole animals (e.g., lab rats)
➢ In Vitro testing: under glass (e.g., liver cells, bacteria, petri dish) ➢
➢ Local toxicity: toxic effect occurs at the site of the exposure (e.g, acid on skin) ➢
➢ Systemic toxicity: requires absorption of the toxicant into the body → then distribution (usually by the bloodstream) to susceptible organs (which is where the toxic effect occurs) (e.g., liver damage, kidney damage)
• Describe chemical absorption, distribution, metabolism, and excretion:
➢ Absorption: by Ingestion, Inhalation, or Dermal contact..
• * When Ingested → Liver!!! → breaks stuff down/uses stuff → Kidney → excretes! (Works together as a team)
• Gastrointestinal system, pulmonary alveoli (for water
soluble), skin (for fat soluble)
➢ Distribution: Once taken into the body the toxin can be distributed throughout the body. If it is lipid soluble it will go to the albumin, most are shunted to the liver and then either metabolized or excreted, through bile or kidneys
➢ Metabolism: metabolic conversion = bio-transformation, a process mediated by enzymes. Goes through GI Trackt → [occurs in] the LIVER! ➢ We also discuss several other topics like What is the cost of debt (rd)?
➢ Excretion: by Feces, Expired Air, Urine
• Characterize the primary routes of human exposure (oral, inhalation, dermal):
➢ Oral: taken in by the mouth
➢ Inhalation: breathed in by the lungs (if particles are too small, they will not be caught by the sticky mucous membrane of the lungs)
➢ Dermal: contact via skin
• Define the four steps of risk assessment:
1) Hazard identification: recognizing when a hazard might cause an undesirable effect.
3) Dose-Response Assessment: How bad is it (toxicology/
epidemiology)? Figuring out the health response to a given dose.
(e.g., LD50, TD50, etc.)
5) Exposure Assessment: What is the probability that people will come into contact with this chemical? Measuring magnitude and
duration of exposure..
7) Risk Characterization: Quantitatively measuring the above steps together to estimate the magnitude of risk.
• Explain the difference in risk assessment logic for carcinogens and noncarcinogens
➢ Risk assessment for carcinogens (cancer): ** Cancer Risk - if number is greater than 10^-4 (e.g.,10 ^- 3, 10 ^ - 2) it's a cancer risk!! If it's lower than 10^-4 (e.g., 10^-5, 10^-6) → gray area, not necessarily a risk.
➢ Risk assessment for noncarcinogens (non-cancer): ** Hazard Index - if number is greater than 1 it's a problem!! (if it's less than 1 → safe!) ➢ We also discuss several other topics like intro to logic rutgers
➢ The difference in risk assessment in carcinogens there is no NOAEL and all and all concentrations are rendered dangerous. If there is greater than 1 in a million then it maybe toxic, whereas a non carcinogen will have a reference dose.
• Calculate environmental risk using estimates of exposure and
RfDs or slope factors
➢ Hazard index = Average Daily Dose/Rfd
• Average daily intake (e.g., .02 for Chloroform example)
DIVIDED by RfD (Reference Dose)
• (E.g., .02 mg/kg/day DIVIDED by .04 mg/kg/day or the RfD = 0.5 → safe!)
• If the number is greater than 1 → unsafe!; less than 1, safe. •
➢ Cancer Risk = average daily intake (e.g., .02 for Chloroform example) x slope factor
• (E.g., .02 mg/kg/day TIMES 0.1 mg/kg/day ^-1 = .002)
• If the number is greater than 10^-4 → Hazardous! So in this case it is hazardous. → CLEANUP NEEDED
• Remember 10^-3 is GREATER than 10^-4! (.001 vs .0001)
➢ 2. Population and Energy Introduction
• Explain how each major energy source is used and their relative percentage contribution in the U.S. energy mix
➢ Petroleum (oil) → 37%
➢ Natural gas → 25%
➢ Coal → 21%
➢ Nuclear electrical power → 9% If you want to learn more check out b) What is the equivalent postfix expression?
➢ Renewable energy → 8%
• Explain the public health impacts of fossil fuel mining, refining, transport, and consumption
➢ * Occupational (COAL MINING, oil refining, mineral exploration) • - can be dangerous
• - methane pockets, explosions
• - dust can incinerate workers..
• - toxic gases/ carcinogenic
• - coal → highest in death rate per kilowatt-hour produced :(
• truck accidents due to hydrofracking
• dangerous machinery
➢ * Food scarcity (10 calories of fossil fuel per calorie of food in the U.S.) • - fossil energy is required to produce food..(19% of total US
• - where does my food come from? → long distances
• - price of food goes up → food stamps are no longer enough
• - meat diet takes double the energy of a vegan diet
• Identify when global oil discoveries peaked and how much oil the United States consumes in a day Don't forget about the age old question of who established the comparison microscope as the indispensable
• Global oil peaked → 1962.
• The US consumes 20 million barrels a day. Each barrel has 42 gallons in it. •
• Apply the energy issues discussed in class to the development of sustainable U.S. energy policy
3. Alternative Energy and Air Pollution Introduction
• Distinguish the pros and cons of the different types of solar, wind, geothermal technologies:
• Pros: Lots of different solar resources, free
• Cons: intermittent and unreliable, fairly expensive, have the ability to alter the environment (e.g., changing rainfall patterns)
• Pros: Free, no energy required
• Cons: Can be inconsistent, best place for wind → middle of the country (but you need to get this electricity back to the coasts),
wind farms take up a lot of land
➢ Geothermal (heat from Earth)
• Pros: ground temperature is stable, geothermal heat pumps can be found/installed anywhere
• Cons: expensive
• Explain the pros and cons of nuclear power and the three ways water is used in a traditional nuclear plant:
• Nuclear power
• Pros: clean source of energy, zero greenhouse gas emissions, no air pollutants
• Cons: possible meltdowns, storage problems (disposal of spent fuel rods)
• 3 Ways water is used in a traditional nuclear plant
• 1) Extracting steam from fuel rods (water flows through fuel rods → becomes extremely hot → this water is radioactive)
• 2) Steam conversion (steam → expands and turns/powers the turbine blades)
• 3) Coolant water (steamed water has to be cooled and converted back to water → so cycle can continue. Fresh water is often
brought in to cool...lots of water consumed. )
• Discuss limiting factors in alternative energy (e.g., water use, transmission, fertilizer, etc)
• Increased water usage → you need energy to use the water.
• Transmission to other parts of the country → requires energy. • Fertilizer → adding to the nitrogen waste.
• Describe each of the 6 criteria air pollutants to include how they are emitted, their human health effects and general corrective actions taken to mitigate the hazard
• 1) Carbon monixide (CO) → reduces the ability of people to carry oxygen to their blood tissue (loves to attach to your hemoglobin → which carries oxygen to your blood)
• 2) NOx (oxides of nitrogen) → goes into the ozone, greenhouse gas → contributes to climate change
• 3) SOx (oxides of sulfer) → acid rain (from coal) → fish can't tolerate lower PH levels due to acid rains → die
• 4) Tropospheric ozone → asthma, affects more Americans than the other five criteria pollutants combined
• 5) Particulate matter
• PM 10 → less than 10 microns
• PM 2.5 → less than 2.5 microns; fine particles → can reach deeper into the lungs
• 6) Lead (Pb): neurotoxin, was added to gasoline in the 1970s → was increasing in ppls' blood → which is why we have unleaded gas now •
• Mercury → mercury vapor → clouds → rain → mercury in fish! •
• Understand the cause, controls, and health implications of thinning Stratospheric Ozone
• Stratospheric ozone layer → good, protective layer! (protects us from UV rays)
• If it thins → we won't be as protected!
• Chlorofluorocarbons (CFCs) → was used in freon in AC units → once CFCs reach the stratosphere the sun breaks apart the
compound --> this releases a chlorine atom that runs amuch and
destroys the naturally occurring ozone
• Ozone in the Troposphere → bad (it's the air we breathe)
• Emitted by: volatile organic compounds (gasoline odor, paints → VOC), oxides of Nitrogen (Nox) → comes from motor vehicles,
4. Public Health and Climate Change Introduction
• Describe how the Chesapeake Bay is impacted by air emissions
• → by Nitrogen pollution → because of cars, fertilizers impacting lawns and rivers, washes from rainfall into rivers and streams → affect the Chesapeake Bay.
➢ Algae + bacteria start multiplying in the water → consume dissolved oxygen → suffocates fish that breathe that → the “Dead Zone”
• Explain how mercury moves through the environment, its health effects and the story of Minamata, Japan
• When coal is burned → releases * mercury (Hg) into the atmosphere, -- > rain washes this mercury into rivers and streams → bioaccumulates
in fish (larget fish eat smaller fish → mercury biomagnifies)
• 1932-1968 Chisso corporation dumps mercury into the sea → bioaccumulates into fish → Minamata villagers consume fish → caused hallucinations, blindness, neural disorders
• Mercury → neurotoxin (why they advise pregnant women not to eat fish) •
• Explain the connection between energy, food and water withdrawal from the Ogallala Aquifer
• "Water Wars" - farmers (food) vs. hydrofracking (natural gas), water is used to produce electricity → Ogallala aquifer drying up, increased heat → Conflict caused by limited resources (oil, food, water) - climate change may increase global instability
• Identify the current CO2 concentration and the pre-industrial CO2 concentration
• In pre-industrial age CO2 → ~ 300 ppm vs. today CO2 → 390 ppm! → so close to 400ppm!
• Explain the greenhouse effect and the influence of short-wave and long-wave radiation
• We do need greenhouse gasses in order for earth to be inhabitable..(warm enough to live) the problem is if there's too much!
• We get a lot of sun/solar radiation coming into the planet, let's a lot of it through → but not all of it leaves! Because its trapped by greenhouse gasses → which is why we're a warmer planet → GOOD thing.. unless it's in disturbing amounts
• The green house effect is important because they absorb heat and when absorption is much greater than being radiated out the planet starts to warm up. •
• Characterize the major greenhouse gases and their relative influence on climate
• CO2 → warming of the climate, lasts a long time
• Methane → 25 times more potent! but short lived
• Melting permafrosts → release methane
• Identify the temperature and CO2 concentration cap agreed to in Copenhagen 2010 by the US and the European Union •
• CO2 temperature cap → 2C or 450 ppm but we are already at a 0.8C (30 years) rise and with all current promised reductions we can still get to 3.0C •
• Discuss how public health is influenced by climate change
• Public health → glacial retreat, Food/Water shortage, wildfires/Deforestation, Heat Waves, dirt storms of the 30s
5. The Built Environment Introduction
• Match a process description to one of the five phases of the life cycle assessment (LCA) framework
• 1. Raw Material Acquisition: What is taken from the environment • 2. Material Manufacture: Making the raw product
• 3. Product Manufacture: Making the product
• 4. Product Use: Most people only focus on this
• 5. Product Disposal: Getting rid of it
• Explain the importance of LCA in alternative energy decision making
• It is important to look at the life cycle assessment of alternative energy because like corn ethanol there is so much put into making the ethanol that it may not even be a good decision. Heavy industrialized machines, fertilizer, irrigation of water, only use the kernels, distillery. With electric cars you have to consider the coal burned for the electricity.
• Discuss the links between building efficiency and environmental/ human health
• 40% energy → homes and buildings
• Commercial → uses more lights → lots of heat
• Smaller buildings + greater insulation → better!
• Explain ways that the built environment impacts health and fitness
• Diabetes, high BP, high cholesterol, heart disease, stress anxiety, all come with a
sedentary lifestyle. We have built a environment where we don’t need to move at all. Everyone wants to have a good easy life (convenience) but we have taken it to the extreme.
• “Diseases of the affluent”
• We have replaced human energy with fossil fuel energy. If we decide to bike to work or walk to work it will not only help the environment but also our bodies. You can lower your foot print and cholesterol at the same time.
• Discuss take-back effects and the importance of health in making sustainable choices
• Take back effects → people think they are saving energy → thus will tend to use more energy.
• Explain strategies in how public health professionals can play a major role in shifting behavior to abate climate change, reduce energy/water consumption, and live a healthier lifestyle
• Makes you healthier, saves money, cleans air and money, and reduces carbon footprint and combats climate change.
6. Food Safety and Global Sanitation Introduction
• Explain the role of the various regulatory agencies responsible for food safety
• - FDA (Food and Drug adminstration)
• - USDA (United States Dept. of Agriculture)
• - EPA (Environmental Protection Agency)
• - National Marine Fisheries Service
• - Bureau of Alcohol, Tobacco, and Firearms
• - Customs Service
• - Federal Trade Comission
• - DHS (Dept. of Human Services)
• → * overlapping responsibilities!!!!!
• Identify the source, health effect, and protective measures for Salmonella and Campylobacter
• Most common sources of human foodborne illness (CDC FoodNet
• - Salmonella
• → Source: spread through direct or indirect contact with intestinal contents or excrements of animals, including humans → foods can be contaminated at many points where food is handled/processed, from "farm to fork”, often associated with eggs or egg-based food (via outside contamination or vertical contamination from the mother),
• → Health effect: infection
• → Protective measures: grows at temps between 41-113F, BUT easily destroyed by cooking to **160F --> also, do not grow (but will survive) at refrigerator or freezer temperatures..
• - Campylobacter
• → Source: caused by consuming food or water contaminated with Campylobacter jejuni bacteria → found in intestinal tracts of healthy animals (esp. chickens) and untreated surface water → * gets into surface water (when maneur runs off the land into the surface water) (usually from fecal to oral route)
• → Health effect: infection
• → Protective measures: easily killed by HEAT (120F)! & doesn't multiply at temperatures below 85F!
• → * which is why we should cook raw meat before eating, and pasteurize milk! •
• Explain the difference between infection and intoxication •
• - Infection: can be caused by Salmonella, Campylobacter, E. Coli, and Listeria bacteria in food
→ when bacteria enters body, multiplies, and causes adverse effect! (bacteria needs to be living!)
• - Intoxication: can be caused by Staphylococcus and Clostridium botulinum bacteria
• → when bacteria produce a TOXIN (poison) as a by-product of growth/ multiplication in food; the toxin causes adverse effect. (bacteria can be dead → but TOXIN is STILL PRESENT!)
• Explain issues/conditions that challenge food safety and some basic food safety practices
• 1) Clean: wash hands and surfaces often
• 2) Cook: cook to proper temperatures
• 3) Chill: refrigerate promptly
• 4) Separate: don't cross- contaminate
• Explain the fecal-oral route of disease and how understanding of
pathways and exposure routes evolved
• Feces → Fluids, Fingers, Flies, Fields/Floods → Foods
• Describe importance of water quantity, water quality, sanitation, and hygiene to public health
• - sanitation (to remove human excreta)
• - hand washing (for fingers)
• - water quality (for fingers and flies)
• - water quantity (for fluids)
• Identify four major intervention areas that WHO promotes for reducing the burden of disease due to diarrhea
• 1) Point-of-use water treatment (e.g., adding chlorine to water) → 30-50% reduction in child diarrheal disease prevalence.
• 2) Safe storage → 21% reduction in diarrheal disease morbidity • 3) Hand washing with soap → 43% reduction in diarrheal disease morbidity • 4) Sanitation → 30% reduction in diarrheal disease morbidity •
• Explain millennium development goals (MDGs) and metrics used to assess water access coverage and global progress toward water and sanitation targets
• - * Target 7c: Halve, by 2015, the proportion of the population without sustainable access to safe drinking water and basic sanitation
• → the world is NOT on track to meet MDG Sanitation Target 7C by 2015! • - 2.5 billion people are still without access to improved sanitation • - 1.1 billion people engage in open-air defecation
• → the world HAS met the target for: reducing the number of individuals who use unimproved drinking sources by half (in 2010)
• - Improved: pumped sources, protected | Unimproved = water from an open source
7. Drinking Water
• Understand the hydrologic cycle and identify drinking water sources and their differences
• The Hydrologic Cycle (steps)
• 1) Atmospheric moisture (from clouds down to Earth..) results in→ • 2) Precipitation (down to Earth!) goes twds →
• 3) Consumptive Use (households, etc.)
• 4) Groundwater
• 5) Surface water
• 6) Saline Groundwater (salty groundwater from the ocean)
• 7) Well
• 8) Ocean
• 9) Evaporation → goes back to #1!
• Identify major health concerns associated with drinking water contamination
• - Protozoa: - in one life stage, exists as cysts → which makes it very resistant to disinfection/ damage! (Amoebiasis; Entamoeba histolytica,
Cryptosporidiosis; Cryptosporidium parvum, Giardiasis; Giardia lamblia ** sometimes called "beaver fever --> spread through the excrement of beavers!. Cyclosporidiosis; Cyclospora cayetanensis)
→ all souce
*** All sources associated with sewage! ***
*** Almost all of these are passed through fecal-oral route ***
* Protozoa life history: 1) Thick walled oocyst exits host → 2) Contamination of water and food with oocysts → 3) Thick-walled oocyst ingested by host → * 4) Excreted into environment → back to 1)!
→ Typhoid fever, Campylobacteriosis, Cholera, Dysentery, Gastroenteritis → ** sewage as primary source!,
→ EXCEPT * Legionellosis → from inhalation of contaminated water aerosol (vs. ingestion) (actually grows in cooling tanks of AC systems..)
- Viral hepatitis (hep A), gastroenteritis (e.g., Norwalk virus) , polio → ** sewage as primary source!
- * Norwalk virus → waterborne + foodborne, but can also be spread by people!! (→ projectile vomiting → has the potential to aerosolize!)
- Chemicals/ other contaminants → most present in drinking water due to the geological formations the water comes out of (e.g., groundwater, runoff)
- Disinfection by-products → occurs via drinking water disinfection processes
• Describe the mechanisms for regulating water quality under the U.S. Safe Drinking Water Act (e.g., MCLs, MCLGs) •
⁃ Safe Drinking Water Act (SDWA): gives EPA the authority to set water quality standards and oversee water suppliers that implement these standards
⁃ must treat and test water, maintain distribution systems, report on water quality to their customers
⁃ → applies to all public water systems but NOT private wells... ⁃ → does NOT apply to bottled water (that is regulated by the FDA!) ⁃
⁃ * EPA sets a National Primary Drinking Water Regulation (NPDWR primary standard), which is a legally enforceable standard.
• - maximum contaminant levels (MCLs) → legally enforceable! • Set as close as possible to MCLGs based on technical feasability and cost
• ** if there's no way to measure the contaminant at a low enough level, EPA may set a treatment technique (TT) instead of an MCL (still legally enforceable)
⁃ National Secondary Drinking Water Regulation (NSDWR or secondary standard) are nonenforceable ..usually for cosmetic or aesthetic effects) ⁃
⁃ Maximum Contaminant Level GOALS (MCLGs): EPA sets MCLGs after collecting/reviewing data on contaminants from health effect
⁃ set at level where no adverse effect expected → at level below reference dose, however carcinogens set at zero since the EPA
assumes no safe level of carcinogens)
⁃ EPA does not consider the ability to measure or remove
contaminants from water when setting MCLGs...
• Understand typical water treatment processes including the characteristics of various disinfectants
* Screening: usually for surface water only
* Coagulation (or flocculation): alum and other chemicals are added to water to form tiny sticky particles, called floc, which attract dirt and other materials. The combined weight of the dirt and the floc is great enough to sink to the bottom during sedimentation. →
* Sedimentation: the heavy particles, made during the coagulation/flocculation stage, settle to the bottom, while clearer water goes on to be filtered. →
* Filtration: water passes through filters, which can be layers of sand, gravel, activated carbon, or charcoal (e.g., Brita) →
*Disinfection: a disinfectant is added to the water to kill any remaining microorganisms →
** Common disinfectants:
- chlorine (PROS: inexpensive, generally very effective, provides a residual.. CONS: not effective against cryptosporidium, produces trihalomethanes and other DBPs )
- ozone (PROS: very effective against cryptosporidium.. CONS: expensive, needs to be generated on site as a gas and is very reactive, produces bromate and other DBPs, does not provide a residual.. sometimes chlorine needs to be added anyway prior to distribution)
- chlorine dioxide (PROS: very effective against cryptosporidium in its cyst stage.. CONS: needs to be generated on site as a gas and is explosive → risk to workers, expensive, produces DBPs similar to chlorine but at lower levels, does not provide a residual.. sometimes chlorine needs to be added anyway prior to distribution)
- chloramines (usually used with another disinfectant, often chlorine, to provide a
residual) (CONS: produces DBPs, but at lower levels than chlorine.. , can change water properties! → e.g., changing the PH level of the water.) •
• Describe disinfection by-products and methods for addressing them and the associated trade-offs
• ** 3 Common DBPs:
• 1) Trihalomethanes: DBP formed when chlorine is used. Potential for cancer and other adverse health effects at high levels of exposure..
• 2) Bromate: DBP formed through the use of other disinfectants, like ozone. Potentially carcinogenic.
• 3) Haloacetic acids: another DBP with toxicological concerns similar to trihalomethanes..
• *** disinfectants are imperfect! we can try to maximize benefits of disinfectants but can't get rid of side effects.. we can try to minimize DBPs..
• Describe the major features of the Clean Water Act (e.g., NPDES)
• * The Clean Water Act (CWA): to restore and maintain the nation's waters →
• * National Pollutant Discharge Elimination System (NPDES) permit program
• → limits facilities' discharge (chemicals, biochemical oxygen demand or BOD, temperature can be considered a pollutant, things that may change the pH)
• * Reauthorization of the CWA in 1987: attention to storm water runoff and "non point" source pollution
• * CWA also gives EPA the authority to dredge and fill waterways (via the Dredge and Fill permit program)
• * CWA also gives Wetlands protection
• Describe the difference between point-source and non-point source sources of water pollution
• - Non-point-source: polluted runoff from the land (comes from a number of different sources)
• - Point-source water pollution: we can identify the EXACT industrial/ wastewater facility
• Explain biological oxygen demand (BOD) and how it is used to characterize the quality of water
* Biochemical Oxygen Demand (BOD)
- a common measure for nutrients (old, low tech, but used commonly) - sometimes called "biological oxygen demand" → measures how much oxygen is used by microbes metabolizing (i.e., eating nutrients in water) ; initial amount of oxygen in bottle is measured (mg/L) → wrapped to keep dark and left for five days → take a final measurement of oxygen after five days
→ ** the difference in oxygen levels = the BOD!
- * the higher the BOD; the higher levels of nutrients in the water → usually a sign of poor water quality
* pristine river: 1mg/L
* moderately polluted river: 2-8 mg/L
* treated sweage: up to 20 mg/L
* raw sewage: up to 800 mg/L
⁃ Hypoxic → too low oxygen level (organisms may die)
⁃ Anoxic → NO oxygen level (organisms WILL die)
• Identify public health concerns associated with water contamination—including recreational uses
• *Recreational Waters : potential for exposure to water-borne illness (in rivers, streams, beaches used for recreation) from pathogens → from microbial agents from runoff, sewage, septic tanks, livestock, wildlife, etc.
• ** major source: wet weather flows (when there is an overflow at a wastewater treatment plant)
• - primary effect: diarrhea (common, but rarely tested → difficult to determine how widespread an illness is)
• - also: additional gastrointestinal illness, skin rashes or infections (particularly if skin is broken), respiratory conditions (if water is breathed in) →
• * Beaches - currently monitor for E. Coli (its presence indicates that water has been contaminated with sewage → since it comes from or is present in the intestinal tracts of animals and humans)
• - problem: tests take two days to get a result! - beaches located near wastewater plants will often be closed after a rain of sufficient magnitude → as a sewer overflow is assumed.
• * The Beach Act of 2000 (been working on this for 10-14 years!): EPA currently working on developing rapid (2-4 hr) methods of detecting pathogens: look for the DNA of E. coli and other pathogens, measuring specific pathogens and new indicator organisms
• Understand the importance of proper sewage treatment in disease prevention
• * Developed following outbreaks of cholera and other diseases in cities around the world..
• * Pipe systems developed → transport waste to rivers or lakes • * Widespread contamination of surface water → prompted the development of wastewater treatment technologies in the late 1800s
• * Sewer systems built to handle three kinds of waste:
• 1) Household
• 2) Industrial
• 3) Storm water
• Explain the function of each stage of a wastewater treatment facility
1) Screens out garbage using 0.5-1.0 sq inch mesh barriers →
2) Wastewater goes to primary sedimentation tank → heavy material sinks to bottom → forms raw sludge
3) Secondary treatment: microorganisms in large aeration tanks break down material in water. Compressed air is added to provide
oxygen to the aerobic bacteria.
4) Final settling tank: wastewater is separated into sludge or recycled water
5) Recycled water can be Class A or (has been through secondary treatment → filtration, disinfection) B/C (only been through
primary treatment → screening, grit chamber, sedimentation tank) 9. Solid Waste
• Explain terminology such as solid, hazardous, and municipal waste
• Municipal: household trash
• Describe the historical events leading to RCRA, SARA, and CERCLA
• 1976 Resource Conservation and Recovery Act (RCRA): how we regulate INDUSTRIAL waste.
• Russell Bliss → hired to spray oil on dusty roads..but unbeknownst to him, the oil was laced with dioxin (a toxic compound) → caused uproar; EPA declared national emergency: town evacuated, 265,000 tons of soil burned! → RCRA was developed for solid waste: any discarded
material from industrial, commercial, government, mining, and
agriculture, including solid, liquid, semisolid, or contained gaseous
material (haha → essentially all forms of matter!)
• 1980 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA): for poorly managed or old, abandoned waste sites (e.g., Love Canal, Valley of the Drums)
• ** Government or responsible party(s) MUST clean up!!
• Love Canal (Niagara, NY): highlighted problem of waste management going unchecked → 1930s-1950s: Hooker Chemical dumps 21,000 tons of toxic waste into this canal --> 1950s: this land was sold to the city for $1 (deed restricted) (The city is made aware that toxic waste was dumped here) → 1960s: deed restriction reversed --> hundreds of homes built on site → 1978: waste found oozing from the site --> panic ensues --> President Carter declares federal health emergency --> ** led to other dump sites being discovered!
• Valley of the Drums (Louisville, KY): 17,000 openly dumped drums were removed from 13 acres
1986 Superfund Amendments and Reauthorization Act (SARA): *Created the Emergency Planning and Community Right-to-Know Act (EPCRA): → Citizens have a right to know about chemicals in their community.
• Inspired by Bhopal, India --> * Dec 3, 1984: release of chemical from company
called Union Carbide; at midnight 42 tons of methyl isocynate (MIC) reacts with water --> over pressurizes tank (bursts the tank)--> released into Bhopal India - ** 3,000 people died immediately, thousands more in the weeks that follow → 20,000+ people with long-term health effects - * considered the "worst industrial accident" in history..
• Explain the legal authority behind RCRA, SARA, and CERCLA •
• Describe the trends in the type of waste, management technologies, recycling, and waste to energy
10. Occupational Health
• Explain the roles/responsibilities of the various organizations involved with occupational health
• Match any control strategy into the hierarchy of hazard controls •
• Explain the difference between eight-hour PELs/TLVs, STELs/ Ceiling Limits, and IDLH
• OSHA uses Permissible Exposure Limits (PELs) --> ACGIH uses Threshold Limit Values (TLVs) ( ** OSHA limits are generally higher than ACGIH's..) --> * BOTH use similar styles in regulating chemicals: 8-hour time-weighted average OR short-term exposure limit (STEL) or Ceiling Limit: - * 8-hour time-weight average: after the end of an 8 hour shift there will be an average concentration of the chemical. The maximum allowable concentration after an 8-hour period. - * Short-term exposure limit (STEL) or Ceiling Limit: exposure over a 15 minute period of time. (Ceiling Limit: you cannot go over this value, period!) - * STEL: max concentration allowed during a 15-minute continuous period (averaged over 15 minute period of time) --> allowed 4x/ day but separated by 60 minute periods of time - * Ceiling Limit: max concentration allowed at ANY length of time (e.g, "50c" = Ceiling limit)
• Explain the difference between the two types of respirators and when they should/should not be used
• Explain the conditions for molds/mildew formation indoors •
• Discuss the various types of physical workplace hazards and
general techniques used to protect the worker
• Name the three industries with the highest fatality “rate” • - construction
• - transportation
• - agriculture/mining
• Explain the three control strategies for repetitive motion injuries (ergonomics)
• - whatever keeps the body in a neutral position
• - reduce force/weight
• - reduce repetition
1. Define key terms and concepts (e.g., NOAEL/LOAEL, LD50, RfD, slope factor)
Risk – to expose to a chance of loss or undesirable outcome.
Assessment – to determine the value, significance, or extent of.
Risk assessment- assess the nature and magnitude of the risk
*Environmental risks are characterized by chronic exposures at very low doses.
Dose-response assessment: How bad is it (toxicology/epidemiology)? Animal studies and accidental human exposure allows us to figure out the health response to a given dose.
Exposure assessment: What is the probability that people will come into contact with this chemical? Magnitude and duration of exposure are major factors.
Risk characterization: This lets us quantitatively measure all the steps together to estimate the magnitude of risk.
*Cancer vs Non cancer
-never mathematically assume there’s a safe dose for cancer risk LD50- Lethal dose where 50% of population die.
TD50- Toxic dose at which 50% of individuals show toxicity LC50- For air; lethal concentration where 50% of individuals die
TC50- For air; toxic concentrations where 50% of individuals show toxicity. Example: ozone
Characteristic S curve in Dose-Response curves
Maximally Tolerated Dose MTD
-used in cancer studies
-highest dose you can give animal before it dies
*On EPA Pesticide Labels- as the number gets bigger- it becomes less severe—meaning it takes more on the poison to kill someone. NOAEL- no observable adverse effect level; highest dose not produce an adverse effect
LOAEL- lowest observable adverse effect level: lowest dose administered that does produce an adverse effect.
Reference dose Rfd: the value of the dose that is assumed to be safe for the human population
To find the reference dose:
We have to divide the uncertainty factor out. *Divide by 10
Rfd= NOAEL/ (Animal to human (H) x Average to sensitive human x LOAEL to NOAEL (L) x Less than chronic to chronic x Data quality (MF) *FOR NON CANCER!!
RfD < NOAEL < LOAEL
2. Explain how toxic agents are identified and characterized-- differentiate between acute and chronic toxicity and tests for each.
Toxicity: Measure of the inherent ability of a chemical to produce injury. The less of a substance it takes to cause injury, the more toxic it is.
-We can describe the toxicity of a substance based on: a. Time: acute vs chronic
b. Location: local vs systematic
Acute toxicity: sudden onset of toxic effect, minutes, hours, or days. Acute does not mean severe. –irritants, chlorine gas
Chronic toxicity: toxic effect after long periods of exposure, usually many months or years. –cancer, liver damage, lung fibrosis
Local toxicity: toxic effect occurs at the site of exposure – pulmonary edema, acid on skin, asbestosis.
Systematic toxicity: requires absorption of the toxicant into the body, the distribution of the toxicant (usually by the blood stream) to susceptible organs, which is where the toxic effect occurs. –liver damage, kidney damage.
Threshold- point where we start seeing negative effects
3. Describe chemical absorption, distribution, metabolism, and excretion
Absorption deals with how things enter into the body. Ingestion is how the majority of chemicals will enter the body, followed by inhalation and then dermal contact.
Things that are ingested and absorbed into the bloodstream go directly to the liver first—this is called the first-pass effect.
In the liver, there are many different kinds of enzymes to break down chemicals in a way that typically prepares them for excretion through the kidneys.
Liver enzymes also manage food so your body can use good things like sugars and proteins.
In a way, the liver acts as sort of a sentry guard to manage chemicals that come in through this major portal of entry – the ingestion route.
4. Characterize the primary routes of human exposure (oral, inhalation, dermal)
We get rid of things in the body by excretion
Feces: food, chemicals, and indigestible materials can go through the GI tract and never be taken up into the body so they just pass right on through in the feces.
Expired air: a breathalyzer test measures the amount of alcohol on your exhaled breath. This accurately correlated to the amount of alcohol in your blood. So we eliminate some volatile chemicals (chemicals that easily go from a liquid to a gas/vapor state) through exhaled air.
Urine: this is the way most chemical are excreted from the body. The body must get rid of things like ammonia created during normal functions, as well as environmental chemicals that inadvertently enter the body. Generally speaking, the liver prepares chemicals for excretion and then kidneys actually excrete. In a way, the liver and kidneys work as a team.
5. Define the four steps of risk assessment
Hazard Identification -------------
Dose Response Assessment -------- Risk Characterization
Exposure Assessment -------------
Hazard identification: We have to recognize when a hazard might cause an undesirable health effect.
*What stage of risk assessment does toxicology best fit? Dose response assessment
6. Explain the difference in risk assessment logic for carcinogens and non carcinogens.
*Need to know the slope of the line to find the cancer risk =SLOPE FACTOR
Cancer risk= Dose x Slope Factor
1 in a billion 10 to -9 : risk is clearly insignificant and unreasonable risk
1 in a 1000 10 to -3 : it would be significant and measures should be taken to reduce the risk
Somewhere in between these two are gray areas. 10 to -6 and 10 to -4
In general, with any labeling system, the closer we get to the number 1, or the letter A, the more certain we are that it is a human carcinogen.
Hazard Index vs Cancer Risk
Hazard index = Average daily intake / RfD
**If Hazard index is < 1 I’m okay , if > 1 not okay **DIS FOR NON CANCER RISK
Cancer Risk = Average daily intake x slope factor
Risks perceived to be voluntary are more accepted than risks perceived to be imposed.
Risk assessment: helps quantify risk and categorize potential threats to human health; subject to considerable uncertainty. Reduces risks to human health and must be based on scientific risk information.
7. Calculate environmental risk using estimates of exposure and RfDs or slope factors
Two types of Animal Toxicity Testing: In Vitro: under glass or In Vivo: in whole animals
Poison: substance or mixture that can be life threatening. The end result is lethal. Knowing the dosage is important here.
Exposure vs Dose
-Exposure deals with things like the air that we breathe, the water we drink, and dermal contact. Some portion of the chemicals that are in the air, water, or soil can enter the body, or all or none of it enters the body. It depends on you and type of chemical.
-Dose refers to the quantity that is taken into the body. There are two types:
1. Administered dose- quantity taken into the body – chemicals ingested like a pill
2. 2. Absorbed dose- the quantity that traverses a biological barrier like the lining of your small intestines or your lung linings to enter the body.
Hydrophobic- fears water, so more of the chemical will be found in the body’s fat tissue
Hydrophillic- loves water, so more of the chemical will be found in the body’s bloodstream (blood is water based)
Lipophobic- it hates fat.
Lipophillic- it loves fat.
Chemicals that are highly lipophilic, like benzene or the pesticide DDT, are not likely to show up in the blood.
The First-Pass Effect
The first-pass effect is everything that is absorbed from the GI tract goes directly to the liver first; the liver metabolizes food, drugs, and toxins.
An enzyme is something that makes a reaction go faster. If a chemical enters the body, live enzymes will change the chemical into something else. In most cases, it converts chemicals into something more water soluble that can be more readily excreted by your kidneys.
*Most of the time, the liver detoxifies a chemical, however, sometimes the liver enzymes will make things more toxic when it breaks things
down. It all depends on the set of enzymes you possess. Everyone is different and the results vary from chemical to chemical. The same dose of a chemical may be more harmful to one person and less harmful to another—we are all highly variable.
Unit 7 Objectives
1. Understand the hydrologic cycle and identify drinking water sources and their differences
2. Identify major health concerns associated with drinking water contamination
3. Describe the mechanisms for regulating water quality under the U.S. Safe Drinking Water Act (e.g., MCLs, MCLGs)
4. Understand typical water treatment processes including the characteristics of various disinfectants
5. Describe disinfection by-products and methods for addressing them and the associated trade-offs
The Hydrologic Cycle
-40,000 billion gallons per day of water are in the atmosphere. -Some of the water falls to earth as precipitation (4,200 billion gallons per day) in the form of rain, sleet, or snow.
-Atmospheric water can sink into the ground, it can run off into water bodies, or it can actually be used for consumptive uses. Evaporation:
-The water that has reached the ground then evaporates back up into the atmosphere.
-Evaporation comes from oceans, lakes, and streams. Sources of Drinking Water
-Some amount of water that gets absorbed into the ground goes into groundwater
-Lakes, rives streams, and groundwater are sources of drinking water. Earth’s Total Water
-Saltwater covers 70% of the Earth’s surface.
-It accounts for 96.5% of the Earth’s water.
-Saltwater cannot be used directly for drinking water or for irrigation. -About 1% of the water on Earth is brackish (salinity between saltwater and freshwater) and it’s found in lakes, seas, estuaries, and groundwater.
-Remaining 2.5% of water on Earth is fresh water. Freshwater can be used for drinking and irrigation.
Of the Freshwater on Earth…
-About two thirds of freshwater is frozen in polar ice caps and glaciers. (66%)
Water Accessible for Human Use
-Only about .3% of total water on Earth is readily accessible for human use.
-This is a very large amount—lakes, rivers, and streams contain over 125,000 cubic kilometers of water.
-That’s a lot of freshwater, but it isn’t always where we want it, when we want it.
Sources of Drinking Water
-Water that falls from the atmosphere can end up in several different places.
-It can seep into the ground and end up in ground water. -It can run off from the land and into rivers, streams, and lakes. This is called surface water.
-It can be deliberately collected for use as drinking water. This is sometimes referred to as protected runoff.
What is Groundwater?
-Groundwater is out of sight but it’s a very important source of drinking water.
-Groundwater is water that is found in the ground.
-It fills the space between soil and rock. The ground that groundwater is in is like a sponge, not like an underground reservoir.
-The water table is the dividing line between the saturated and unsaturated zone. The saturated zone is where the groundwater is.
Benefits of Groundwater
-Groundwater has been used as a source of drinking water for a very long time.
-It is available where it’s needed and costs very little to access. -Usually free of contamination. Low or no levels of bacteria, viruses, suspended solids, or chemicals.
-In the US, groundwater is the water source for 50% of the population.
Drawbacks of Groundwater
-Groundwater is limited in volume; it’s essentially irreplaceable once depleted.
-Groundwater can become contaminated through human activity. Think about source protection.
-Contaminated groundwater can be very difficult to clean out; protection and prevention is the best way to go.
-Any potential source of hazardous materials or pathogens leaking into the ground and contaminating the drinking water source is a pubic health hazard.
-A variety of human activities (personal, commercial, industrial, municipal) could potentially contaminate water.
Potential Hazard: Landfills
-Landfills can contain hazardous waste or pathogens that could leak into the groundwater if not properly constructed. Location is also important.
-Proper construction includes lining the landfill with a clay barrier, plastic liner, and covering the refuse with compacted soil daily.
Potential Hazard: Gas Station
-Leaking underground storage tanks have been a source of contamination in the past.
-Considerable action has been taken to retrofit underground storage tanks to keep them from leaking.
Potential Hazard: Dumping in Lakes
-Hazardous materials dumped into lakes can end up in groundwater.
Potential Hazard: Animal Manure and Septic Waste -Can potentially contaminate water with pathogens, microorganisms, protozoa, and viruses.
Potential Hazards: Pesticides and Fertilizers
-Can run off into groundwater as well.
Industrial Emissions-can run into groundwater as well.
-Protecting groundwater means keeping those activities far enough away from our water sources that it doesn’t end up in drinking water. -The dashed line around the well shows a protection area. This is called wellhead protection.
-Potential contamination sources should be placed outside of the area to prevent hazardous materials from leaching into the water. Surface Water
-Surface water is water that comes from lakes, streams, and rivers. -Often requires extensive treatment before consumption to clean out pathogens and bacteria.
-Drinking water often competes with other uses for surface water like irrigation, industrial use, fisheries, and habitat for species. -Possible to deplete water source with various competing uses.
Protected Runoff: Two Kinds
After groundwater, another source of drinking water is protected runoff, which is collecting precipitation in an artificial impoundment for future use. There are two kinds of protected runoff:
-Have been used for centuries to capture rainwater to be used for drinking.
-Basilica Cistern in Istanbul built in 6th century.
Modern Example of a Cistern
-Can be almost anywhere. Water that falls off the roof of a dwelling can be captured and run into an underground, protected cistern. -That water can then be taken from the cistern and run back into the home for bathing and washing dishes.
-Cisterns are widely used around the world.
-A reservoir captures fallen precipitation (rain, sleet, or snow) in an artificial impoundment.
-Reservoirs are often formed with dams and can cover a very wide area.
-The reservoir serves as a drinking water source.
On average, every person in the US uses 50 gallons of water per day.
On average, about 15-25 gallons of that 50 gallons consumed every day are used for flushing toilets.
15-20 gallons of that 50 gallons consumed every day are used for bathing.
Only 2 quarts are consumed in cooking and drinking.
The rest is used for washing machines, pools, and irrigation of lawns and gardens.
Other Uses of Water in the US
Industrial: Includes 48% used for cooling in thermoelectric power generation
Irrigation: Uses a large amount of water (34%). Much less water is used for livestock, mining, and aquaculture.
Public supply: 11%
Number of outbreaks decreasing over time
-Not the best way to understand underlying rates of waterborne disease.
People don’t get sick enough to go to the doctor.
Key Waterborne disease agents
Protozoa one life stage exist as cysts—very resistant to disinfections
c. Giardiasis (most common) Beaver fever
*All sources associated with sewage
*Passed through fecal-oral route
Thick-walled oocyst ingested by host
Thick-walled oocyst exits host
Contamination of water and food with oocysts
Gastroenteritis: E.coli 0157:H7
Legionellosis* - inhalation of contaminated water aerosol Appeared in late 70s. Grows in water tanks.
*Sewage again is primary source
Viral Hepatitis (Hep A)
Norwalk virus- people can spread it as well as food or water. Projectile vomit- can aerosolize the virus.
Arsenic, asbestos, cadmium, chromium, copper, lead, selenium
Natural deposits, runoff, water system
Natural deposits, runoff from fertilizer use, leaking septic tanks
Pesticides, volatile organic compounds
discharge from industrial facilities, leaking landfills
Drinking water disinfection processes
Arsenic in Drinking Water in Bangladesh
1970s Bangladesh has serious problem with waterborne disease. Govern and international aid agencies began digging shallow tube wells
-wells access groundwater, avoid surface water contaminated with pathogens
-very successful, incidences drop
-but early in 1990s, signs of excessive arsenic exposure: skin lesions, potentially linked to skin/bladder cancer
Current estimates: one third of tube wells exceed WHO suggested arsenic limits of 10 ppb; persons with poor nutrition are highly susceptible.
-Many organizations around the world working on removing arsenic. UC Berkeley group using coal ash to remove arsenic from drinking water ARUBA
-very cheap system, cost-beneficial and safely disposed.
Safe Drinking Water Act
-gives EPA authority to:
a. set water quality standards
b. oversee water suppliers that implement standards.
Applies to all public water systems in the US- but not to private wells.
Not applied to bottle water- by FDA
-Covers public water systems- can be pretty small
-EPA and state governments set and enforce standards -local governments and private water suppliers have responsibility for insuring water quality
-treat and test water
-maintain distribution systems
-report of water quality to customers.
-A National Primary Drinking Water Regulation (NPDWR or primary standard) is a legally enforceable standard
a. max contaminant levels (MCLs)
b. treatment techniques (TT)
-A National Secondary Drinking Water Regulation (NSDWR or secondary standard) is a non-enforceable guideline
a. Cosmetic effects
b. Aesthetic effects
Maximum Contaminant Level Goals
-After collecting/reviewing data on a contaminant from health effects studies, EPA sets an ACLG
-MCLGs are non-enforceable public health goals a. set a level where no adverse effect expected
b. set at level below reference dose, after drinking water consumption compared to RfD and other potential sources of exposure to contaminant.
c. Set at zero for suspected carcinogens.
d. Does not consider ability to measure or remove contaminant from water.
Next step, Maximum Contaminant Level (MCLs)
- Once MCLG is established, EPA sets an enforceable standard called a maximum contaminant level (MCL) a. Set as close to MCLG as possible
b. Based on technical feasibility and cost
- If there’s no reliable method to measure contaminant at low enough level, EPA may set a treatment technique (TT) instead of an MCL.
a. Is still enforceable
b. Is a technology or procedure (performance standard) that must be followed.
SDWA Amendments of 1996
1. Require EPA to publish a list of unregulated contaminants of cancer (CCL list)
2. Must review at least five contaminants every five years. 3. To regulate, EPA must show three things:
a. contaminant adversely affects human health
b. it is known to or substantially likely to occur in public water systems with a frequency and at levels of public health concern
c. regulation of the contaminant presents a meaningful opportunity for health risk reduction
4. Also required reporting to water system customers through consumer confidence reports.
Learning Objectives for Unit 6
1. Explain the role of the various regulatory agencies responsible for food safety
2. Identify the source, health effect, and protective measures for Salmonella and Campylobacter
3. Explain the difference between infection and intoxication 4. Explain issues/conditions that challenge food safety and some basic food safety practices
5. Explain the fecal-oral route of disease and how understanding of pathways and exposure routes evolved
6. Describe importance of water quantity, water quality, sanitation, and hygiene to public health
7. Identify four major intervention areas that WHO promotes for reducing the burden of disease due to diarrhea
8. Explain millennium development goals (MDGs) and metrics used to assess water access coverage and global progress toward water and sanitation targets
Diarrheal diseases is responsible for 1.5 million deaths per year - down from 5 mill in the 1980s
- 90% of disease associated with poor water supply, sanitation, and hygiene
- #2 cause of under 5 mortality
- Geography plays a role in this number
- Previously thought that malnutrition drove susceptibility to diarrhea
- Newer evidence suggest that diarrhea can result in malnutrition. - 50% of malnutrition is due to poor WASH conditions - Not always about food production when determining factor of malnutrition
- 41% Africa & 37% Southeast Asia highest percentage of under 5 year mortality
- 6-11 mths- highest number of specific incidence for diarrheal episodes
Millennium Development Goals
-set of goals we can track and monitor to improve development -water and sanitation was included- specific targets set for 2015 - Goal 7, Ensure Environmental Sustainability
Target 7C: Halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation 1 Indicator 7.8: Proportion of population using an improved drinking water
Indicator 7.9: Proportion of population using an improved sanitation facility
11% (783 million people) of global population lack access to great water
An estimated 653 million rural dwellers lacked improved sources of drinking water in 2010.
Disparities in different regions of the world: making progress towards reducing overall bad water
Ground is being lost in urban areas because of urbanization and migration to cities- development of slums. Municipalities can’t keep up.
Improved water source doesn’t always mean clean water Estimated 1.8 billion use unsafe water. (28% of global population)
More than a quarter of the population takes greater than 30 minutes to collect the drinking water.
Significant increase in illness/risk for people living further from water supply.
-less water brought back
-more energy needed
Safe removal of human excreta
Not solid waster, food safety, or home and workplace cleanliness Sanitary interventions, not necessarily construction.
2.5 billion without access to improved sanitation
-world is not on track to meet MDG sanitation goals
Progress in rural areas, falling behind in urban areas.
More than half of Africa is not using improved sanitation Not just about infrastructure, it includes upkeep as well
Access to hardware, hygiene promotion, enabling environment- 3 legs highlighted for hygiene improvement. Not just providing a well or treatment, but behavior and communication is improved too
Fecal-oral route of disease (F-diagram)
-clean water supply
-hygiene/ hand washing
By these interventions- estimated reduction in diarrhea:
Point of use water treatment: 30-50% reduction. Twice as effective as interventions as water source
Safe storage: 21% reduction
Hand washing: 43% reduction
Sanitation: 30% reduction- basic, low cost systems
-Water can be contaminated at the source.
-Can be contaminated during transport handling, and storage. * How do we take care of this situation?
-household water treatment options:
-ceramic filtration, biosand filtration, solar disinfection, boiling water*indoor air quality probs
*What is appropriate?
-Affordable, available locally, cultural acceptable, easy to maintain, sufficient capacity, environmentally sound.
-strong behavioral change strategy
-maintain a narrow focus
-reinforce key behaviors and develop strong system for follow-up to increase sustainability
Foodborne Illness in the US
-CDC estimates: 48 million illnesses; 3,000 deaths
-many cases are relatively minor; pathogens not always identified USDA regulated products: 1,344 outbreaks
FDA- regulated products: 3,323 outbreaks
Outbreak: when an illness suffered by multiple people is able to be traced back to a single source.
-estimated 70,000 illness cases (diarrhea, fever, abdominal pain) -1 in 15 leads to complication, kidney failure, intense pain, death -first identified as food pathogen in 1982.
Viruses: Norwalk, hepatitis A
Protozoa: cryptosporidium, giardia
Mycotoxins: aflatoxin, ochratoxin
CDC has several means of surveillance: they interact with state and local health departments
Foodnet: an active surveillance network run by CDC
Pulsenet: molecular fingerprinting of foodborne illness
Relative rate. Above 1- more cases. Below 1, means there are fewer.
Wide range in number between cases of pathogen. Most have downward trends.
Consequence of foodborne illness
- different pathogens have different severities.
- Norovirus- most common foodborne illness- very rarely death
- Salmonella/listeria: associated with many more deaths
Top 5 pathogens causing foodborne illnesses
Top 5 causing hospitalization
E.coli (STEC) 0157
Infection vs Intoxication
Infection caused Salmonella, Campylobacter, E.coli, and Listeria bacteria in food
-bacteria enter body, multiply, cause adverse effect
Intoxication caused by Staph & Clostridium botulinum -produce toxin (poison) as by-product of growth/multiplication in food; toxin causes adverse effect.
-bacteria can be dead, but toxin still present
Most common sources of human foodborne disease Salmonella
-caused by consuming food or water contaminated with Campylobacter jejuni bacteria
-found in intestinal tracts of healthy animals (especially chickens) and untreated surface water
-fecal to oral route of contamination
-consume raw or inadequately cooked foods of animal origin, no chlorinated water
-grows best in a reduced oxygen environment
-is inhibited by acid, salt, and drying
-will not multiply at temp below 85 degrees F
- spread through direct or indirect contact with intestinal contents or excrement of animals, including humans
- foods may contaminated at many points where food is handled - often associated with eggs or egg-based products
- poultry meat, processed meats, milk products
- grow at temperatures between 41 degrees and 113 degrees - easily destroyed by cooking to 160 f
- do not grow, but can survive at refrigerator or freezer temps
Federal food regulatory agencies
National marine fisheries service
Bureau of alcohol, tobacco, and firearms
Federal trade commission
Different responsibilities from different agencies- patchwork of laws, regulations, and responsibilities –overlapping responsibilities
Who plays the biggest role: local government health inspections
Different states have different ways how they track/monitor food safety.
HACCP-Hazard Analysis and critical control points- ensure quality and safety of food during processing
-produced by NASA and Pillsbury
-systematic approach- maps production process and identifies what is bad
-involved monitoring, record keeping, constant verification -deals with temperature, and people handling the food
Food safety at home
- 4 main points WHO uses:
- 1. Keep area clean: wash hands and surfaces often - 2. Separate: don’t cross contaminate
- 3. Cook: cook to proper temperature
- 4. Chill: refrigerate promptly
Unit 4 Learning Objectives:
1. Describe how the Chesapeake Bay is impacted by air emissions 2. Explain how mercury moves through the environment, its health effects and the story of Minamata, Japan
3. Explain the connection between energy, food and water withdrawal from the Ogallala Aquifer
4. Identify the current CO2 concentration and the pre-industrial CO2 concentration
5. Explain the greenhouse effect and the influence of short-wave and long-wave radiation
6. Characterize the major greenhouse gases and their relative influence on climate
7. Identify the temperature and CO2 concentration cap agreed to in Copenhagen 2010 by the US and the European Union
8. Discuss how public health is influenced by climate change Unit 4
How Energy Impacts Public Health
-CO, Hg, Sox, NOx, particulates, ozone,
-Acid rain, mercury, NOx, acidic mine tailings
-alternative energy often requires lots of water
-Coal mining, oil refining, mineral exploration
-10 calories of fossil fuel per calorie of food in the US
-health care, infrastructure, transportation rely on oil
-affordability of medicine, environmental protection, humanitarian relief
-international, regional, and personal security
-greatest public health threat humanity ever faced
Coal increases Mercury levels
We see the highest levels of mercury in predator fish like shark, marlin, swordfish, walleye, largemouth bass, and northern pike.
Mercury is a neurotoxin, so it affects the nervous system. It can lead to decreased IQ, language skills, memory, and attention deficit disorder.
Another unexpected form of nitrogen pollution that enters our waterways comes from cars. Over 20 million people live in the Chesapeake Bay watershed. Cars emit oxides of nitrogen (NOx) that washes out from rainfall into the rivers and streams that lead to the Chesapeake Bay. About 35% of the nitrogen pollution in the bay is from automobiles.
After nitrogen enters the water, algae and bacteria start multiplying with all this new food they are getting. As the algae and bacteria bloom, they consume the dissolved oxygen in the water, which suffocates the fish that breathe the dissolved oxygen through their gills. This causes what is referred to as the "dead zone," which happens in most estuaries for the same reason but with the large population of lawn and farming activities, the dead zone in the Chesapeake Bay is quite large.
Nitrogen loading- is a chain of events; NOx favors blue and green algae. This depletes dissolved oxygen in water, chokes out underwater grasses, crabs, oysters, fish.
Human infection by flesh-eating bacteria called Vibrio has doubled in 10 years around the Bay area.
The Ogallala Aquifer
-World’s largest natural underground aquifer
-Like an enormous lake beneath the surface
-94% used for crop irrigation
- In Texas, OK, KS, Nebraska
-We have been able to produce the food we do in these areas, because of this aquifer
-Water consumption rate is way higher than retention rate
Center pivot irrigation centers- 1 point in the ground and the other spends above the ground. Takes about two days to spin across field. Fertilizer produced by natural grass
-An acre of corn requires 4,000 gallons of water
Ethanol vehicle consumes 130-6,200 gallons of water depleted to travel. Way more than gasoline.
Impact of Energy
-lower food production
19% of total energy in the US goes into food production Meat diet takes double the energy of vegan diet
Derechos- land hurricane, are fueled by heat waves when extreme temperature differences in front systems collide.
Maslow’s Hierarchy of Human Needs
-The basics of human needs have to be met in order things like life, love, and belongingness to occur.
-When needs are met, order happens.
-National defense is almost entirely dependent on oil (petroleum)
1. Increased CO2 concentrations are from human fossil emissions 2. Mauna Loa, Hawaii- shows concentration of global CO2 measurements
3. CO2 highest in spring; lowest in fall – plant seasonal 4. NASA temperature map. Colder regions on the globe are warming faster than relative warmer areas.
5. Global average snow levels have declined
6. Incoming and outgoing solar radiation chart- only reason life in habitable is because of green house gases. Those gases absorb heat that makes up our atmosphere. Our atmosphere is letting more heat in than out. Green house gases are trapping them.
3 undeniable facts about climate change
1. We’re pumping 33-35 gigatons of CO2 into atmosphere 2. CO2 absorbs infrared radiation
3. Earth is warming
Different foods have different GHG emissions
1. Red meat
Methane is 25 times more potent than CO2
By flaring off Methane, you are converting to CO2, which is better. *
Melting permafrost releases methane.
Vostok Ice Core Data- calibrate the ice and read about the history of temperature through this by measuring CO2 levels.
Ice Age and Warming period- 90,000 then 10,000. Due to planetary alignment.
We have never experienced 300 ppm CO2 since 400,000. 450ppm is the point of no return
Public Health impacts of climate change
*once in a lifetime events are happening every few years
As ocean warms, water expands, and creates a rise in sea level. More CO2 is being dissolved in ocean, creating acidic oceans and destroys coral reefs
Disease migration- the territory expands when the globe warms. West Nile, Malaria, Dengue fever.
Climate change doesn’t have direct ramifications, but a confounding factor of food, water, energy, and health. Each rely on each other to work.
-countries rely on winter snowpack for drinking water -melting snowpack causes flooding
-threatens water flow
-getting very low flows and very high flows- not very steady Rapid ice melting in Greenland and Arctic summer ice
Reason why Europe has a much hotter climate than Nova Scotia is because of ocean currents. Greenland ice melts and is starting to
influence this saline flow of water. They can actually stop or slow currents. Climate is thrown into chaos. Micro-ice ages in Europe could occur.
Oil is the most commonly used fossil fuel, and accounts for 35 percent of the world’s energy consumption; coal account for 23 percent and natural gas 21 percent.
About 85 percent of plastics are derived from petroleum (oil).
Oil fuels over 95 percent of global transport.
42 gallon barrel of oil has many uses, but the majority of oil is used to produce/transport fuels, including gasoline, diesel, and jet fuel. Around 60% of petroleum was used for transportation in 2005. By 2030, 58% of liquid fuel production is anticipated to go to transportation worldwide.
Oil peaked in 1970s.
Coal produces more CO2 emissions than other fossil fuel and is responsible for the majority of cumulative atmospheric CO2 above preindustrial levels, but petroleum is now responsible for more emissions in absolute terms.
It is a sedimentary rock composed of the fossilized remains of prehistoric vegetable matter preserved from biodegradation by water and mud.
Peat is its precursor. It is composed primarily of carbon and hydrogen but includes small amounts of other elements, most importantly sulfur.
Coal is the primary source of electricity generation worldwide. Coal is 25% of the total primary energy production.
China was the world’s leading producer in 2006 with 2.4 billion tons.
Natural Gas, is often found with oil deposits; its prehistoric organic matter was subject to higher temperatures than those that produced the adjacent oil. It is also found in coal beds and in isolated natural gas fields.
It is a mixture of several different gases, primarily methane but also ethane, propane, butane, and pentane and several inorganic gases, such as CO2, nitrogen, helium, and hydrogen sulfide.
*It has fewer impurities, so it is less polluting, and it produces more energy per unit than petroleum or coal. It also generates about 30 percent less CO2 than petroleum and 45 percent less than coal.
*Its main disadvantages are difficulties of transport and storage, given its volatility and low density.
Biomass fuels are a heterogenous group of organic materials generated by plants through photosynthesis. They are produced on a human time scale, ranging from months to decades. This includes wood, corn husks, coconut shells, peat, and animal dung.
Unit 8 Objectives
1. Describe the major features of the Clean Water Act (e.g., NPDES) 2. Describe the difference between point-source and non-point source sources of water pollution
3. Explain biological oxygen demand (BOD) and how it is used to characterize the quality of water
4. Identify public health concerns associated with water
contamination—including recreational uses
5. Understand the importance of proper sewage treatment in disease prevention
6. Explain the function of each stage of a wastewater treatment facility
• Deuteronomy 23:12-13: God gave instructions to Moses on sanitation for human waste.
• 2800 BC: Minoans in Crete develop flush toilets.
• 1595: Sir John Harrington designs flush toilet.
• 1854: Broad Street cholera outbreak.
1 John Snow maps source of cholera and removes Broad Street pump handle.
• 1855: George Vanderbilt has first indoor full bathroom (tub, sink, toilet).
1872: Sir Thomas Crapper develops modern toilet design.
Widespread contamination of surface water prompted the development of wastewater treatment technologies in the late 1800s.
Sewer systems were often built to handle three kinds of waste: 1. Household
3. Storm water
Recycled wastewater can be:
1 Class B/C
2 Class A
Class A water has been through a tertiary/secondary treatment.
Tertiary treatment can involve filtration or disinfection with chlorine or UV light.
Primary treatment (Sewer Systems)
• Grit chamber: captures grit (from roads after it rains) • Sedimentation tank: uses gravity to settle heavy materials at bottom
Secondary treatment (Sewer Systems)
1 Aeration tank: water is bubbled to keep bacteria growing. 2 Settling tank: activated sludge is returned to aeration tank.
Tertiary treatment (Sewer Systems)
• Sometimes used to remove nutrients, contaminants, and to reclaim water.
• Treated water can even meet drinking water standards.
Clean Water Act
-Restore and maintain the nation’s waters.
National Pollutant Discharge Elimination System (NPDES) permit program
-Limits facilities’ discharge
-Limits: Specific chemicals, biochemical oxygen demand (BOD), temperature, pH.
1987: attention to storm water runoff and non-point source pollution
-Dredge and Fill permit program
-directly discharging into water
-two main sources: industrial, and wastewater treatment facilities
Major concerns: sewer overflows
-occur when volume of wastewater overwhelms plant; flow is too fast. -can lead to direct discharge of untreated waste water -can be minimally treated (with chlorine)
-can be stored in a holding facility
Combined Sewer Overflows:
-occurs in systems where storm water and sewage are combined -often in older cities
-flow too great for treatment plant
CWA requires permit from National Pollutant Discharge Elimination System (NPDES)
-permits require technology-based standards
-must use best available technology depending of discharge -set for categories: municipal wastewater plants must use secondary treatment.
-extra steps can be taken for water quality standards: used when receiving waters don’t meet water quality standards. Based on site specific.
Receiving Water Bodies: creeks, streams, rives, lakes, ground water.
Storm water: impervious surfaces (building, roads, parking lots prevent rainwater from infiltrating into the ground.
-much storm water is captured in sewer systems
-is a source of chemical (road oil, fertilizer, road salt) and other pollutants
-may also increase erosion through channeling.
Addressing Storm Water
-Increase water infiltration: stone paving or bricks where water can run between, research into more pervious surfaces (concrete). -Slow the flow: rain barrels capture water running off roof. Can be used or later released at slower rate into sewer system.
-Rain gardens: allows water to pool; natural or man made formation, like swamps.
-Rules on chemical use in agriculture, landscaping, etc- governing pesticides
-Erosion control in construction.
Non-point source pollution is different from point-source pollution, where we can identify the exact industrial/wastewater facility.
Non-point source pollution is polluted runoff from the land. It is not coming from one place, but from a number of sources. Agricultural or urban runoff flows into streams, rivers, lakes, and oceans.
Main concerns involving non-point source pollution are: pathogens, nutrients, toxins.
Non-point source pollution is not regulated under NPDES. Except for storm water that’s captured and goes to a wastewater treatment facility.
-In many places, it’s the largest source of uncontrolled pollutant discharge into water bodies.
Pathogens- same as those for drinking water: bacteria, viruses, protozoa. Sources: humans: septic tanks, combined sewer overflow, livestock, wildlife.
Testing for Non-Point Source Pathogens
-presence of E.coli in water is measured.
Nutrients: Nitrogen, phosphorus- both necessary for plant growth. Excess of nutrients, microorganisms in algae, grow very quickly, and when that happens, they eventually die and decompose, which uses up oxygen in the water, and fish die from lack of oxygen.
Biochemical Oxygen demand (BOD)
-common measure for nutrients
-old, low-tech, but used commonly
-measures how much oxygen is used by microorganism. -initial amount of oxygen in bottle is measured (mg/L)
-bottle if often wrapped to keep dark and left for five days -difference in oxygen levels after five days is the BOD. *higher the BOD, the higher levels of nutrients in the water. (We want fewer though!)
Hypotoxic- too low oxygen level
Anoxic: no oxygen
Non-Point Source Toxins:
Besides pathogens and nutrients, there is also concern about toxics that can wash off the land into water bodies.
-Toxics from Motor Vehicles: Gas, oil, and grease from motor vehicles -Toxics from Agriculture and Lawn Care: pesticides, fertilizers, and other materials from agriculture and lawn care.
-Toxic from Metals: Metals from motor vehicles and other sources
-Toxic Through Atmospheric Deposition: Pollution may occur through atmospheric deposition. Toxins that are emitted into the atmosphere may come when it rains or naturally deposit into a water body.
Recreational Waterborne Illness:
-Similar agents to drinking water concerns—microbial agents from runoff, sewage, septic tanks, livestock, wildlife, etc.,-- are the cause. -The major source is wet weather flows, where there is an overflow at a waste water treatment plant.
-The primary effect is diarrhea, which is common, but rarely tested, making it difficult to determine how widespread an illness is. -Other effects include: additional gastrointestinal illness, skin rashes or infections, respiratory conditions
Beaches currently monitor for E.coli
-Present in the intestinal tracts of animals and human is an indicator pathogen.
-Its presence indicated that the water has been contaminated with sewage, due to a wet weather flow.
-Problem: the current test takes two days to get a result. In reality, beaches located near wastewater plants will often be closed after a rain of sufficient magnitude; a sewer overflow is assumed.
EPA and the Beach Act
-The Beach Act of 2000 tasked the EPA with reducing the risks from recreational waters.
-The EPA is currently working on developing rapid methods for detecting pathogens.
-The EPA has been working on this mix of research and regulatory activity for the last 10 years.
Unit 9 Objectives:
For live session, students who had the same recycled material will present their findings on the material such as how much of the material is currently recycled, how the material is collected, energy savings, indirect health implications, etc. The information can be either U.S. focused or based on the student’s home country.
1. Explain terminology such as solid, hazardous, and municipal waste
2. Describe the historical events leading to RCRA, SARA, and CERCLA
3. Explain the legal authority behind RCRA, SARA, and CERCLA 4. Describe the trends in the type of waste, management technologies, recycling, and waste to energy
Solid Waste Management
Industrial waste: more hazardous
Municipal Solid waste: regular waste
1950s openly dumping industrial waste in backyard.
1976 RCRA: How we regulate industrial waste today
1980 CERCLA: For poorly managed or abandoned waste sites (Love Canal, Valley of Drums) *Taking care of sins of the past.
1986 SARA: Bhopal, India
1990 Pollution Prevention Act
*Times Beach, Missouri gave life to RCRA (Resource Conservation and Recovery Act)
Russell Bliss: paid to spray oil on roads to keep dust down. Oil being used was laced with dioxins, toxic compound. Spread everywhere. Town evacuated. 265,000 tons of material burned.
RCRA: defines solid waste: any discard material from industrial, commercial, government, mining and agriculture, including solid, liquid, semisolid, or contained gaseous material.
Listed: Nonspecific: Toluene, MEK, etc/Specific: sludge from steel making plant. Characteristic: Toxicity, Reactive, Ignitable, Corrosive. (2 > pH > 12)
*Exclusions: Domestic waste: banana peels, fossil fuels, mining waste, oil and gas refining waste, hydrofracking. Chemical might be, but not the process itself.
Not considered a RCRA hazardous waste. About 500 coal plants in the US. Coal contains 10% ash (minerals that won’t burn). Typical coal plant: 4,000 tons coal/day, 400 tons coal ash/day.
In 2008: Coal ash- 2.5lb/person/day
Us. Trash: 4.5lb/person/ day
What do we do with Coal Ash in the US?
22% Surface Impoundments
37% Beneficial Use
8% Mine Fills
RCRA: Subtitle C: Hazardous Waste; Subtitle D: Nonhazardous waster; Subtitle F: FED waste: Subtitle I: Underground Tanks
*Should Coal Ash be regulated under Subtitle C or Subtitle D?
Waste to Energy** Inceneration, reduces volume and cost of getting rid of trash
*If one drop of hazardous waste drops in a 55 gallon, the entire barrel is hazardous
*You have 90 day of on site storage, then has to move on a more permanent facility.
*You have to be a licensed operator, training, etc. Spill kits, secondary containment.
*You cannot treat waste. Can’t manipulate.
Landfills are complex in design and structure. If properly built and maintained, they have a low likelihood of leaking hazardous materials into the groundwater. Below is a description of some of their key components:
1. Compacted clay layers: these slow the movement of water and chemicals.
2. Leachate collection system: any liquid that gets to the liners is pumped back up to the top of the landfill.
3. Groundwater monitoring well: these are used to test the groundwater to ensure that no hazardous materials have escaped and contaminated the groundwater.
4. Rainwater retention ponds: when it rains, runoff is channeled into retention ponds instead of through the landfill.
Leaking Underground Storage Tanks—Regulation
By 1988, the EPA required all gas stations to have:
• Spill and overflow protection
• Corrosion protection on any underground tanks
• Double-walled tanks with leak detection between the walls This regulation excluded tanks used for home heating oil on farms and for residential use.
1980 CERCLA: Super Fund Site: Clean up sins on the past. Old abandoned dump sites.
Most famous: Love Canal- New York- highlighted problem of waste management going unchecked. 1930s-1950s Hooker Chemical dumps 21,000 tons of toxic waste.
1950 land sold to city for $1 (deed restricted- told city they dumped toxic waste). People forgot about it, because it was covered up. Deed restriction is lifted; homes and schools are built. Things ooze out of the crowd. Prez Carter declares a federal health emergency. 1980: CERLCA made; toughest law in the books.
Updated- SARA established
Valley of the Drums: you can actually see the barrels- in Louisville, KY 17K openly dumped were removed. Love Canal- you couldn’t see- it was underground
CERCLA: nicknamed superfund: for abandoned or uncontrolled waste sites: National Priorities List.: locates hazardous waste sites, based on health hazard ranking system.
-1,600 NPL sites in country
-Gov’t or responsible party must clean up.
-Tough Law: Retroactive: all past and current owners liable. -Strict: liable regardless of whether all laws of the day were followed. -Joint and several: one small waste generator can be liable for all.
Remember back to our one in a million (10-6) cancer risk and below the reference dose (RfD) for noncarcinogens? These are the targets we generally use to determine how clean is clean enough for Superfund sites. When you understand the numbers, it’s a pretty satisfactory level of clean.
1986 SARA: Superfund Amendments and Reauthorization Act: Bhopal, India 1984: Release of chemical from Union Carbide- now Dow Chemical. Worst industrial accident in history. At midnight- 42 tons of MIC reacts with water, over pressurized and burst. 3,000 died immediately. Thousands more die in weeks after. 20,000+ with long term health effects.
-Eyes burning, trouble breathing. Very low economic area.
-Today, 90 tons of toxic chemical are abandoned at the Union Carbide plant now owned by Dow Chemical.
-Causes huge trust issues between us and India.
-Created Emergency Planning and Community Right-to-Know Act (EPCRA): requires emergency planning for spills and releases. Established the Toxic Release Inventory Program (TRI): got companies to clean up their act.
1990 Pollution Prevention Act: prevent pollution from occurring in the first place.
Municipal Solid Waste (MSW)- garbage, trash, and items we throw away every day
-4.5 lb/day/person, Roughly doubled since 1970.
-About one third is packaging material.
Always something left over at burning: ash/slag: leftover noncombustible material.
Today’s Waste Stream is different (many small amounts) 2006 cell phones have increased 1.5 billion per year. 72% of Americans own a cellphone.
Average user replaces his or her cellphone every 1.5 years. We have become a very disposable oriented society.
Cradle to Cradle: product manufacture use reuse it
Unit 10 Objectives- Occupational Health
1. Explain the roles/responsibilities of the various organizations involved with occupational health
2. Match any control strategy into the hierarchy of hazard controls 3. Explain the difference between eight-hour PELs/TLVs, STELs/Ceiling Limits, and IDLH 4. Explain the difference between the two types of respirators and when they should/should not be used
5. Explain the conditions for molds/mildew formation indoors
6. Discuss the various types of physical workplace hazards and general techniques used to protect the worker
7. Name the three industries with the highest fatality “rate”
8. Explain the three control strategies for repetitive motion injuries (ergonomics)
Occupational Health aka Industrial Health
Anticipation, Recognition, Evaluation and Control
1 Anticipation: anticipate the hazards in a type of workplace. 2 Recognition: observe and recognize various health hazards. 3 Evaluation: exposure assessment (measure duration and
intensity). Compare exposure to risk-based standards. 4 Control: If there is a hazard, we can control the hazard.
ACGIH- American Conference of Governmental Industrial Hygienists. Private organization. Puts out guidelines, recommended guidelines. (TLVs)
Occupational Safety and Health Act (1970) set up the administration OSHA. To ensure so far as possible every working man safe and healthful working conditions.
OSHA- legal authority created NIOSH- National Institute of Occupational Safety and Health- research.
1970- OSHA adopts 1968 ACGIH Exposure Standards
1980 Benzene decision- US Supreme Court.
What is significant?
1 in 1000: OSHA allows more risk than EPA (1 in a million)
Types of Workplace Hazards
1 Chemical: Gas/Vapor, Aerosol (particles), skin contact 2 Physical: Ergonomics, Noise, Radiation, Heat/Cold stress, Building (mold/mildew)
3 Biological: Use safety hoods, goggles. No good air sampling.
Concentration is what you use in occupational setting.
Occupational Exposure Limit: 40 years of work, 40 hours per week. (OSHA)
OSHA: PELS (permissible exposure limits
ACGIH: Threshold Limit Values (TLVs)
*8 hour time weighted average or Short term exposure limit (STEL): allow exposure limit or Ceiling Limit: never allow past a certain point.
Acute: Short term exposure limits
Chronic: 8 hour time weighted average
Short term exposure limit (STEL) or Ceiling Limit -used when a chemical can harm within a short period of time (cyanide)
STEL: max concentration allowed during a 15 minute continuous period allowed 4x/day, 60 minutes between.
Ceiling: max concentration allowed at any length of time.
Odor Threshold: lowest concentration detected by smell (often too high)
Olfactory fatigue: hydrogen sulfide gas aka sewer gas: you smell it for a few minutes, but your brain shuts out the smell.
Immediately dangerous to life and health (IDLH): limit to where death may occur within 30 minutes; mainly used in emergency response.
Biological exposure indices (BEI): bioindicator of exposure (blood, urine, breath); concentration of chemicals in biological fluids and tissues.
Balometer- measure air flow in and out of buildings.
Hot Wire: air flow rate in lab hood that could potentially harm patients. Acide plating tank: acid mist; use a ventilation system. Hexavalent Chromium: painting aircrafts
Explosive gas detection: combustible gases, oxygen levels, hydrogen sulfide, carbon monoxide.
The hierarchy of hazard controls, from most to least desirable: 1 Elimination: getting rid of a hazard from the
2 Substitution: replacing one substance or
activity with a less hazardous one.
3 Engineering: installing filters, ventilation,
noise-absorbing walls, scrubbers, guards, etc.
4 Administrative: procedures to reduce
opportunity for exposure.
5 Personal protective equipment (PPE):
respirators, ear plugs, goggles, gloves, boots,
Canary suits protects from alpha particles.
Gamma Radiation Defense: Time, Distance, and Shielding.
Respiratory Fit Test Program: annually must be fit tested. Secure fitting around the test. Lung function test.
Many different types of cartridges- must match the pollutants.
Two Major Respiratory Categories
1 Air purifying respiratory- must use the nearby air (never use in low oxygen, highly hazardous, or unknown environments).
Disposable masks, half mask, full-face piece, gas mask.
2 Supplied Air Respirators- comes with its own air supply. a. Airline respirator, self-contained breathing
apparatus, emergency escape (if you can
leave a building quickly, no need to use
Personal protective equipment: pressure test and proper maintenance and storage.
Molds and Mildews
Love 68-90 degree F. Desirable range. They love anything greater than 60% humidity.
Wet Bulb Globe Temperature: accommodation of 3 things: Dry-Bulb Temp, Humidity, Globe Temperature (Radiate Energy aka Sun)- can come from furnace in a ship, anytime you have an elevated heat source; different from outside temperature
*Very humid day, the wet bulb temperature is about the same as the dry bulb temperature.
-Lockout/tagout: equipment is locked out so no one can turn it on while someone is working on it.
-Both hands require use when using machinery
-Make sure people are protected and can do their job.
Transmission of Sound:
Goes in middle ear bone, then cochlea nerves ending that are sent to the brain.
When you damage nerve ending, then that’s it, can’t regrow nerve endings.
Lasers: High-powered laser can acutely damage eye nerves.
In 2010, construction had the most number of fatalities but agriculture/forestry, mining, and transportation had the highest fatality rates.
Primary control methods for repetitive motion injuries are: 1. Reduce repetition (# of times/day)
2. Reduce force/weight
3. Position- maintain near neutral
Unit 2Learning Objectives
1.Explain how each major energy source is used and their relative percentage contribution in the U.S. energy mix
-Coal: 42% - Most abundant fossil fuel in the world 25% of World total in US
-Basically all coal consumption is for electricity. -600 coal fired power plants in the US.
-Consumption decreasing, production increasing -Exports to India and China
-Coal to liquid conversion produced more greenhouse gases than traditional oil.
-In most all of electricity production, we are just boiling water. Heating water, turning it from a liquid to a gas, then we’re turning it from a gas back into a liquid using cooling water. Water is consumed in the US goes to produce electricity. Mostly used in the cooling water to bring gas back to liquid. -Coal produces high mercury, sulfur, particulates (summer haze) released to air and water. Not humidity……… haze linked to cardiovascular disease, etc
Natural Gas: 26%
2. Explain the public health impacts of fossil fuel mining, refining, transport, and consumption
3. Identify when global oil discoveries peaked and how much oil the United States consumes in a day
*World oil discoveries peaked in 1962
Petroleum industry began in 1859 in Oil Creek, Penn 1859-1940 (80 years) – US supplied 66% of world oil 1950- US supplied 50% of world oil
1970- US imports 23%
2010- US imported 68%
*Over time production, consumption increased
Life span of oil field is 40-60 years
*US started out with more oil than Saudi Arabi.
5. Apply the energy issues discussed in class to the development of sustainable U.S. energy policy
Electricity consumption continues to grow and can be attributed to developing nations like India, China, and Brazil.
As their economies grow and more people enter the middle class, they consume more electricity.
Two types of Solar power:
1. Photovalatic- makes direct current electricity directly from the sun
2. Concentrating solar power: sun boils water, converts to steam to produce electricity
Renewable Portfolio Standards: States require a percentage of utilities’ power to come from renewable energy. Cali leading the way.
20% of US electricity comes from nuclear power
Uranium mining is concentrated in western half- primarily in the Easter Rockies
Nuclear plants in the eastern half where more power is demanded. Most Nuclear plants were built before 1970
Three ways water is used in nuclear power plant:
1. Extracting steam from fuel rods: In the first water cycle, the water flows through the fuel rods and becomes extremely hot. This water is also radioactive because it’s in direct contact with the fuel rods. *If the water pumps stop moving the cooling water, the fuel rods will heat up and could cause a radioactive release of steam or a meltdown as the fuel rods get hotter.
2. Steam Conversion: Water is converted to steam then back to water again. When water turns to steam it expands rapidly, which turns the turbine blades, and a generator that is basically a large drum surrounded by magnets and cooper wires produces electricity. So the water in this cycle is in a closed loop (it does not escape) and it draws heat from the contaminated water to turn to steam and generate electricity.
3. Coolant water: the steam now has to be cooled and converted back to water so the cycle can continue. The plant will need coolant water typically brough in from a large outside source like a nearby river or lake. This water often evaporates through cooling towers as it cools the steam, so fresh water can be consumed in this part of the process. Half of all water consumption in the US is used in thermoelectric plants (to include coal and natural gas as well).
1. Electricity- can only be done in certain parts of the world 2. Geothermal heat pumps (heat/cool homes)
You need at least 250 F to make electricity.
Heat pump is using the ground- exchanging temperature with the Earth.
Heat pump ground loops: Horizontal, Pond, Slinky, and Vertical *Much more efficient when using Ground temperatures Ocean Power- many different, wave power, ocean thermal radiance. *Kinetic motion of waves. You need a lot of ocean to create power.
Biomass: burning wood. Boiling biomass
20 million wet ton biomass and burn it, you would have .3% of total electricity used.
Corn Ethanol: not preferred by scientists
Deprives soil of nutrients (water hungry)
Only kernel is used
National Academy of Life Sciences- is worse for health and the environment than regular gasoline; low energy and low output
Algae: plant to aquatic world
-downside- low lipid content; ideal lipid content is 40% -doesn’t do well in outside would, need to find in natural environment -won’t make a BIG contribution
Sustainable energy improves environmental health
1. Air pollutants
-cancer, asthma, mercury in fish
2. Industrial accidents:
-oil spills, explosions, mine collapse
3. Fossil depletion
-peak oil, numerous impacts to health and economy
4. Climate change
-heat wave deaths, disease, crop loss
Burning fossil fuels emits air pollution
Fuel + Oxygen -Carbon dioxide + Water + Carbon monoxide + Particulate Matter (soot)
Nitrogen + Oxygen NO(x) -- Ozone
S + Oxygen SO(x) + Water Sulfuric Acid
Mercury Mercury Vapor
Atmosphere: 5 layers
1st layer: Troposphere: most amount of air (90%) – ozone on the ground- we don’t want this, we don’t want to breathe ozone. (0-10 km) 2nd layer: Stratosphere: Ozone layer (naturally occurring) 10-50km
The relative diameter of the Earth is 12,000km
50km thick and represents troposphere + stratosphere, where 99.5% of air exists.
1948- Penn: 22 deaths- 5,000 affected: Thermal inversion and low winds allowed pollutants to build up
1952- London- 4 day episode- 4,000 deaths: Thermal inversion 1969- public outcry over multiple environmental disasters 1970-EPA est, creates Clean Air Act- 6 criteria air pollutants (NAAQS) New issue: Climate change
National Ambient Air Quality Standards:
1. Carbon monoxide- inefficient combustion, binds with blood’s hemoglobin reducing blood O2 carrying capacity
2. NOx- acid rain, makes ozone, contributes to climate change 3. Sox- acid rain (from coal)
4. Tropospheric ozone- asthma, affects more Americans than the other five criteria pollutants combined
5. PM 10 to PM 2.5 (particle microns) – heart and lung diseases 6. Lead (Pb)- neurotoxin, mostly solved with unleaded gas
*All 6 created through burning fossil fuels
*Leaded Gasoline- now banned
9ppm is UNSAFE with Carbon Monoxide
Nonattainment: haven’t obtained goal; dirty air. According to Clean Air Act
PM2.5 can go deep into the alveolar region of the lung, harder to scrub out (where no mucus is). Smaller, MORE TOXIC, because they are smoke particles.
Summer Haze made worse by 2.5 diesel particles.
PM10 (which are bigger) can be scrubbed out, through mucus, easier because they usually lie in the upper tracheobronchial tree.
Lungs flush themselves out every 24 to 48 hours. A new set of lungs every few days.
PM2.5 Health Effects
-heart attacks and heart disease
increased respiratory symptoms
decreased lung function
You can’t measure ozone. It is a secondary exposure. Ozone consists of three things:
1. VOC – volatile organic compounds
2. NOx – Oxides of Nitrogen
-Form Troposphere Ozone
Clean Air Scientific Advisory Committee (CASAC) Conclusions: -lower ozone standard to 0.06-0.07 ppm
-Prez Obama suspended EPA proposal to reduce from 0.08
Stratospheric ozone protects us from ultraviolet radiations. The three types of ultraviolet radiation ar UV-A, UV-B, and UV-C. Stratospheric ozone is best at filtering UV-C, which does the most genetic damage to our DNA. UV-B can still cause damage, but most of it is filtered out by stratospheric ozone. Most of UV-A gets to the ground but isn’t strong enough to cause damage. Filtering out all of UV-C and most UV-B that allows terrestrial life to exist. Without the stratospheric ozone layer, there would be too much genetic damage for life as we know it.
Chlorofluorocarbons (CFCs) are a very stable chemical historically used in our air conditioners and refrigerators. CFCs are basically a carbon atom surrounded by various numbers of chlorine and fluorine atoms. Dow Chemical produced CFCs under the brand name Freon. Though CFCs are heavier than air, air currents bring them up to our stratosphere over time. Once CFCs get to the stratosphere, the sun is powerful enough to break the compound apart, which releases a chlorine atom. Here the free chlorine atom runs amuck, destroying the naturally occurring ozone (O3) into O2 and O molecules. In fact, the most extreme impact from CFCs can be seen with a widening “hole in the ozone layer” over Antarctica.
When the sun breaks CFCs apart, the stratospheric ozone is in trouble. One chlorine molecule can destroy an average of 100,000 ozone
molecules. The more the stratospheric ozone thins, the less we are protected from UV radiation.
In the late 1980s, world leaders united to combat the thinning ozone layer. They signed the Montreal Protocol, an international treaty that banned the use of CFCs. As this chart demonstrates, atmospheric CFC concentrations are beginning to reverse. It’s taken decades, but we're finally seeing signs of the ozone repairing itself.
Unit 5 Learning Objectives
1. Match a process description to one of the five phases of the life cycle assessment (LCA) framework
2. Explain the importance of LCA in alternative energy decision making
3. Discuss the links between building efficiency and
4. Explain ways that the built environment impacts health and fitness
5. Discuss take-back effects and the importance of health in making sustainable choices
6. Explain strategies in how public health professionals can play a major role in shifting behavior to abate climate change, reduce energy/water consumption, and live a healthier lifestyle
-Most Americans tend to focus on the Use Phase- “Product Use” -Europeans have truly internalized life cycle thinking. They think upstream and downstream. This is a more holistic approach of thinking about a product.
-Looking at the entire process of creating a paper bag is a mind blowing thing.
Corn Ethanol- looks green, feels green, it is green, but it is not very green.
Raw material acquisition, material manufacture, product manufacture, product use, product disposal all add to the energy emission to corn ethanol.
Ethanol has 30% less energy than gasoline.
Electric vs Gasoline Cars
-Hybrid and electric cars use pretty much the same amount of energy based on consuming different types of electrical energy. If an electric car uses advanced coal or natural gas, it emits almost the same amount as a hybrid car. Only if the electric car uses nuclear or renewables, then you see a drop in emission.
Cash for Clunkers
- That new vehicle has some embedded carbon dioxide emissions and when it is no longer used, another vehicle has to be created to replace it. Creates embedded green house gases.
- Clunker tax: $365/ ton CO2
- Carbon tax: $30/ ton CO2
- If you think through life cycle assessment, we could have saved a lot more money
Size of Country reflects mineral wealth
-North America and Europe has been using theirs for years. South America, Australia, and China has an abundant supply.
No more gold in Spain anymore.
Amount of import to the US- graphite, magnesium… we are out of these things and create vulnerable areas in US.
Iron is easy to recycle
Aluminum is less easy to recycle
The way we recycle in the US is different than they do in Europe. We use more machinery and energy in our recycling process than in different countries.
China is building one to two new coal power plants each week. 75% of China’s electricity is coal.
Mainland China has about 30 nuclear power plants in construction and more about to start.
China has built the world's largest hydroelectric dam (Three Gorges Dam). The dam has been controversial because it flooded large forested areas, covered archeological and cultural sites, and displaced 1.3 million people
In 2000, 2.1 million cars were sold in China. In 2008, that figure ballooned to 9.5 million. As more people move from poverty to middle class, this figure will continue to grow.
If everyone lived a healthy lifestyle, it would also reduce our carbon footprint. When you consider what goes into producing a burger— maintaining pasture, raising cattle, meat rendering, transportation, packaging, cold storage, and so on—you get a sense of the greenhouse gas emissions, not to mention our health.
Our modern society has made life much easier and more convenient but living large also comes with health ramifications. Here's a list of diseases that tend to increase when economy and energy consumption begin to rise—call them the "diseases of the affluent."
3. High cholesterol
4. High blood pressure
5. Heart disease
Why does physical fitness tend to suffer in affluent societies? It could be argued that in some ways, we've replaced human energy with fossil fuel energy. In agrarian societies, we worked the land with our hands. Now we have tractors, fast food, and grocery stores.
Circle of Influence- Self, family, friends- personal and professional influence. You can influence them.
Your circle of interest- you can’t influence. You can look on to it.
What I can do:
Buying energy efficient appliances
Buying energy efficient installation- cost beneficial
*Jobs and economy gets better
Bottled water vs tap water
Summer grilling outside
Turn the lights off- it heats up things
Ziploc bags vs containers
Aluminum foil and wax paper
Dual flushed toilet- liquid vs solid waste- really good
Mass transit- great bang for buck
Telecommuting- work at home
Modifying the built environment to increase healthier lifestyle- moving parking lots farther from buildings
Mass transits for bicyclers
Shower at work****
Make the stairs awesome!
Making bike lanes safe- urban planning and development- that are away from traffic
Drive thru windows- creating a lazier environment
Automatic doors- little things add up
Fireplaces- remote controlled natural gas fireplace vs splitting your own wood for energy
Food & Diet
-French fries are made for us to like them
-Once you are on a nutritious diet, you start to crave that. Not fast foods.
-Natural system is our life support system.
-During WW2, ads were to grow gardens, to save money, because mass food was needed to military
-Herbicides and fertilizers were not used. Using marigolds as a natural pesticide.
-Reduces your carbon footprint.
-Vitamin D- We spend 90% of time indoors. 36% of Americans have a Vitamin D deficiency.
-May be linked to cancer, depression, and anxiety.
-Vast majority of Vitamin D is from sunlight. 20 minutes a day. Benefits of Gardening
-better disaster preparedness, stored food
-diversifies water consumption- you distribute water when you distribute gardened food
-learning lost arts of canning and gardening
-lowers gas emissions
- stress reliever
Take Back Effect
-If people use compact fluorescent light bulbs, or LED light bulbs, leave tend to leave them on longer.
-If you buy a hybrid vehicle, people tend to drive it more because it is better of energy.
Opt Out vs Opt In
-consent to donate organs doubled if opting out was the default.
Having an energy consumption in the kitchen buy dollar consumption provides tremendous feedback.
Neighborhood energy watch system, below average (consuming less that neighbors), above average.
When dealing with people, you have to deal with behavior elements that you need to stay aware of.
Energy Use US (All Forms)
a. Residential- 22% of Buildings
b. Commercial- 18% of Buildings
*Differs a little where you are.
* Heating and cooling takes most of the percentages (31% heating in residential)
*Lights for Commercial is 26% vs 11% in residential
84% of energy heating, cooling, hot water, and electricity is found in the “product use” phase of LCA
12% of energy is used for manufacturing, transport, and construction, this is found in raw material acquisition, material manufacture, product manufacture.
*Net zero building- produces as much energy as it consumes -thrift energy consumption, tone down what you don’t need. Don’t build what you don’t need.
*Wood heat/supplemental heat
*Rain water for toilet flushing
*Good installation in attic and walls
U.S. Green Building Council- LEED Certified
Based on point structure
*BEST IS PLATINUM
Brown field- old run down place- that has already been used. This is the best to move into, energy wise.
Concrete foam block walls- energy efficient. Increases thermal mass, heat is retained to night time use.
LED lighting- taking over old light bulbs
Solar hot water- produce hot water from sunlight.
Geothermal heat pump- if your house is efficient, you may never have to use geothermal heat pump
Rain harvesting to flush toilet water
Day lighting- solar piping that pipes light into house
*Long side of house, facing south, to get more sun. *Winter sun is lower, summer sun is higher.
*Passive solar design- really large over hang
*Floor is ceramic-masonry that obtains heat in winter months. *7 billion people on the planet means rapid consumption of our natural resources. We have to become more sustainable.
Sustainable Energy Lifestyle
-makes us healthier
-cleans air and water
-reduces carbon footprint and combats climate change