ENVIRON CHEMISTRY ENVS 4101
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This 7 page Class Notes was uploaded by Judson Rippin on Tuesday October 13, 2015. The Class Notes belongs to ENVS 4101 at Louisiana State University taught by R. Portier in Fall. Since its upload, it has received 34 views. For similar materials see /class/223065/envs-4101-louisiana-state-university in Environmental Science at Louisiana State University.
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Date Created: 10/13/15
ENVS 4101 Exam 1 Study Guide Key Concepts Layering Layering of lake water as it warms in summer can prevent the dispersion of ef uents from tributaries causing increased concentration of pollutants near the shore University ofWisconsin Extension Service Acidity capacity factor Alkalinity intensity factor the capacity to accept H ion Speciation the properties of metals dissolved in water depends largely upon the nature ofmetal species dissolved in the water therefore speciation of metals plays a crucial role in their environmental chemistry in natural waters and wastewaters Chelating Agents chelation is the special case of complexation in which a ligand bonds in two or more places to a metal ion A chelating agent has more than one atom that may be bonded to a central metal ion at one time to form a ring structure More stable than complexes with unidentate ligands Are common potential water pollutants Ligand the species that binds with a metal ion CN EDTA a natural source ofa chelating agent It is a metabolite of the soil actinomycete It is biodegradable and has been used as an extractant for phytoremediation EDDS Polyphosphates a multiple chain of phosphates When used for water treatment polyphosphates quotsequesterquot calcium ion in a soluble or suspended form The effect is to reduce the equilibrium concentration of calcium ion and prevent the precipitation of calcium carbonate in installations such as water pipes and boilers When water is softened properly with polyphosphates calcium does not form precipitates with soaps or interact detrimentally with detergents THMs suspected carcinogen could be formed in the presence of humic substances during the disinfection of raw municipal drinking water by chlorinations The humic substances produce THMs by reaction with chlorine The formation of Thms can be reduced by removing as much of the humic material as possible prior to chlorination Are a group of four chemicals that are formed along with other disinfection byproducts when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water The trihalomethanes are chloroform bromodichloromethane dibromochloromethane and bromoform The Anthrosphere the fifth environmental sphere to be considered It consists of the many things humans make or do Industrial Ecology views an industrial system as an artificial ecosystem with primary sources of raw materials and energy and with a number of enterprises making use of what would otherwise be waste products of other members of the system practiced in a manner that minimizes environmental impact while optimizing utilization of resources energy and capital Sustainability the maintenance of the Earth s carrying capacity that is its ability to maintain an acceptable level of human activity and consumption over a sustained period of time Green Chemistry can be defined as the sustainable safe and nonpolluting Practice of chemical science and manufacturing in a manner that consumes minimum amounts of materials and energy while producing little or no waste material Toxicology Chemistry relationship between the chemical nature of substances and their toxic effects Effects Eutrophication caused by excess productivity Decay of excess biomass Consumption of oxygen BOD Biochemical oxygen demand is a chemical procedure for determining the rate of uptake of dissolved oxygen by the rate biological organisms in a body of water use up oxygen It is not a precise quantitative test although it is widely used as an indication of the quality ofwater BOD can be used as a gauge of the effectiveness of wastewater treatment plants It is listed as a conventional pollutant in the US Clean Water Act Henry s Law 0H39 Cair Cwater How you calculate the solubilities of gasses in water The solubility of a gas in a liquid is proportional to the partial pressure ofthat gas in contact with the liquid HAA5s are a group of chemicals that are formed along with other disinfection byproducts when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water The regulated haloacetic acids known as HAAS are monochloroacetic acid dichloroacetic acid trichloroacetic acid monobromoacetic acid and dibromoacetic acid Glossary Dissolved Oxygen The amount of oxygen present in the water column More than 5 parts oxygen per million parts water is considered healthy below 3 parts oxygen per million is generally stressful to aquatic organisms Erosion Wearing away of rock or soil by the gradual detachment of soil or rock fragments by water wind ice and other mechanical chemical or biological forces Estuary A coastal water resource where fresh water from rivers mixes with salt water from the ocean Eutrophic Usually refers to a nutrientenriched highly productive body of water Eutrophication A process by which a water body becomes rich in dissolved nutrients often leading to algal blooms low dissolved oxygen and changes in community composition Eutrophication occurs naturally but can be accelerated by human activities that increase nutrient inputs to the water body Ground water The water that occurs beneath the earth s surface between saturated soil and rock and that supplies wells and springs Loading The in ux of pollutants to a particular water body Mineralization The conversion of humus and soil organic matter into inorganic substances by microbial breakdown Neurotoxin A poisonous compound that acts on the nervous system Nitrate A form of nitrogen which is readily available to both aquatic and terrestrial plants as a nutrient Nitrification The oxidation of ammonia to nitrate and nitrite yielding energy for decomposing organisms Ppm Ppb Turbidity A measure of the amount oflight intercepted by a given volume ofwater due to the presence of suspended and dissolved matter and microscopic biota Increasing the turbidity of the water decreases the amount oflight that penetrates the water column High levels of turbidity are harmful to aquatic life 0 Watershed The area of land from which rainfall andor snow melt drains into a single point Watersheds are also sometimes referred to as drainage basins or drainage areas Ridges of higher ground generally form the boundaries between watersheds At these boundaries rain falling on one side ows toward the low point of one watershed while rain falling on the other side of the boundary ows toward the low point of a different watershed The Importance of Water Throughout history the quality and quantity of water available to humans have been vital factors in determining their well being Whole civilizations have disappeared because ofwater shortages resulting from changes in climate Even in temperate climates uctuations in precipitation cause problems Devastating droughts and destructive oods are problems in many areas of the world Relationships 0 Sustainability and Energy energy is the key to sustainability 0 Sustainability leaving Earth in a condition to support future generations 0 Sustainability requires energy that is I Sustainable I Safe I Abundant I Essential harmless to the environment I Affordable Relative Toxicity Exogenic and Endogonic Risk Temperature Endogenic cycles which predominantly involve subsurface rocks of various kinds Exogenic cycles which occur largely on Earth s surface and usually have an atmospheric component A major goal in the manufacture and use of commercial products and indeed in practically all areas of human endeavor is the reduction of risk There are two major aspects of risk 0 The hazard presented by a product or process 0 The exposure of humans or other potential targets to those hazards This relationship simply states that risk is a function of hazard time s exposure It shows that risk can be reduced by a reduction of hazard a reduction of exposure and various combinations ofboth Solubility of 07 1474 mgL 832 mgL 703 mgL 0 C 25 C 35 C Illustration of the Definition of Environmental Chemistry The branch of chemical science that deals with the production transport reactions effects and fates of chemical species in the water air terrestrial and biological environments and the effects of human activities thereon Pollutant sulfuric acid by the oxidation of sulfur dioxide generated during the combustion of coal 0 The pollutant sulfur dioxide is generated during the combustion of sulfur in coal transported to the atmosphere with ue gas and oxidized by chemical and photochemical processes to sulfuric acid Sulfuric acid in turn falls as acidic precipitation where it my have detrimental effects such as toxic effects on trees and other plants Eventually sulfuric acid is carried by stream runoff to a lake or ocean The Five SDheres of ani where its ultimate fate is to be stored in solution in the water or precipitated as solid sulfates hpmich39v Atmosphere a thin protective blanket that nurtures life on Earth and protects it from the hostile environment of outer space by absorbing energy and damaging ultraviolet radiation from the sun and by moderating the Earth s temperature to within a range conducive to life Hydrosphere contains the Earth s water a vitally important substance in all parts of the environment Geosphere consists of solid earth including soil which supports most plant life Composed of solid ironrich inner core a molten outer core mantle and the crust Biosphere living organisms and the aspects of the environment all living entities Anthroshpere the ways in which humans do and make things with materials and energy The close relationships among air water and earth environments with each other and with living systems as well as the tiein with technology the anthrosphere Lake Stratification The Predominant Species formed by C02 dissolved in H20 depends on the pH as shown below What s up goes down and comes back up what s down comes up and back down One of the components of the atmosphere can speciation and break because it can be active as different forms at different pHs Low pH equilibrium shift to the left hydrogen groups are shifting back and forth as C02 dissolves Ifyou didn t have C02 going back to HCO3 we wouldn t have C02 going into photosynthesis which helps us We take C02 out of the atmosphere and but it in a primary producer as a plant so we can use it for photosynthesis and then it comes back to us Because C02 can move in different pHs we can have life on this planet Calcium in Water Of the captions found in most freshwater systems calcium generally has the highest concentration Minerals are the primary source such as o Gypsum o Domite Calcium and a few other minerals accounts for water hardness Temporary hardness is due to the presence of calcium and bicarbonate ions in water and may be eliminated by boiling the water The equilibrium between dissolved carbon dioxide and calcium carbonate minerals is important in determining several natural water chemistry parameters such as alkalinity pH and dissolved calcium concentration Phosphorus Cycle Phosphorus is the limiting nutrient in ecosystems There are no common stable gaseous forms of phosphorus so the phosphorus cycle is endogenic In the geosphere phosphorus is held largely in poor soluble minerals such as hydroxyapatite a calcium salt deposits which constitute the major reservoir of environmental phosphate Soluble phosphorus from phosphate minerals and other sources such as fertilizer us taken up by plants and incorporated into nucleic acids that make up genetic material of organisms Mineralization of biomass by microbial decay returns phosphorus to the salt solution from which it may precipitate as mineral matter Twelve Principles of Green Chemistry Minimize or eliminate the need for waste cleanup by emphasizing waste prevention To the extent possible all materials involved in making a product should be incorporated into it This rule involves the key concept of atom economy discussed below Avoid the use and generation of hazardous substances that may harm humans or the environment Design and use chemical products that have minimum toxicity Minimize or eliminate the use of auxiliary substances that do not become part of the final product Solvents are examples of such substances that should be avoided if possible Minimize energy consumption Use renewable raw materials instead of depletable feedstocks For example biomass raw material which can be produced renewably by plants is preferable to petroleum of which there is a finite supply In organic synthesis the use ofprotecting groups should be avoided because the materials used in such groups do not become part of the final product Reagents should be chosen for maximum selectivity of function Products that will be released to the environment or discarded as wastes should break down rapidly to innocuous materials An excellent example of this is the replacement ofnondegradable alkylbenzene sulfonate ABS detergent surfactants with biodegradable linear alkyl sulfonate LAS surfactants in the 1960s 0 Manufacturing processes should be monitored and controlled inprocess and in real time with appropriate computerized systems 0 Processes and materials that are likely to cause extreme temperatures or pressures or unforeseen incidents such as explosions runaway reactions and fires should be avoided Humic Acid 0 The most important class of complexing agents that occur naturally are humic substances 0 The are degradationresistant materials formed during the decomposition of vegetation that occur as deposits in soil marsh sediments peat coal lignite or in almost any location where large quantities ofvegetation have decayed o Ifa material containing humic substances is extracted with strong base and the resulting solution is acidified the products are a material that precipitates from the acidified extract called humic acid 0 Humic acid is insoluble and affects water quality through exchange of species such as captions or organic materials with water 0 The binding ofmetal ions by humic substances is one of the most important environmental qualities of humic substances 0 Humic substances are biodegradationresistant residues remaining from the biodegradation ofplant biomass Basil Convention 0 Where the discussed the illegal dumping issue 0 They never signed something to help it though China Pollution Problems
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