regulatory agencies, and at best are instrumental in developing profitable pollution control products and processes Some background in environmental chemistry should be part of the training of every chemistry student. The ecologically illiterate chemist can be a very dangeror species. Chemists must be aware of the possible effects their products and processes might have upon the environment. Furthermore, any serious attempt to solve environmental problems must involve the extensive use of chemicals and chemical processes ol t here are some things that environmental chemistry is not. It is not just the same old chemistry with a different cover and title. Because it deals with natural systems this har re complicated and difficult than"pure chemistry Students sometimes find rd to grasp, and some traditionalist faculty find it impossible. Accustomed to the clear-cut concepts of relatively simple, well-defined, though often unrealistic systems, they may find environmental chemistry to be poorly delineated, vague, and confusing. More often than not, it is impossible to come up with a simple answer to an environmental chemistry problem. But, building on an ever-increasing body of knowledge, the environmental chemist can make educated guesses as to how environmental systems will behave Chemical Analysis in Environmental Chemistry One of environmental chemistrys major challenges is the determination of the nature and quantity of specific pollutants in the environment. Thus, chemical analysis is a vital first step in environmental chemistry research. The difficulty of analyzing for many environmental pollutants can be awesome. Significant levels of air pollutants may consist of less than a microgram per cubic meter of air. For many water pollutants, one part per million by weight (essentially I milligram per liter)is a very high value. Environmentally significant levels of some pollutants may be only a few parts per trillion. Thus, it is obvious that the chemical analyses used to study some environmental systems require a very low limit of detection However, environmental chemistry is not the as analytical chemistry which is only one of the many subdisciplines that are involved in the study of the chemistry of the environment. Although a"brute-force" approach to environmental control, involving attempts to monitor each environmental niche for every possible mutant, increases employment for chemists and raises sales of analytical instru- ments, it is a wasteful way to detect and solve environmental problems, degenerating into a mindless exercise in the collection of marginally useful numbers. Those esponsible for environmental protection must be smarter than that. In order for chemistry to make a maximum contribution to the solution of environmental problems, the chemist must work toward an understanding of the nature, reactions and transport of chemical species in the environment. Analytical chemistry is fundamental and crucial part of that endeavor Environmental Biochemistry The ultimate environmental concern is that of life itself. The discipline that deals specifically with the effects of environmental chemical species on life is C 2001 CRC Press LlC
regulatory agencies, and at best are instrumental in developing profitable pollutioncontrol products and processes. Some background in environmental chemistry should be part of the training of every chemistry student. The ecologically illiterate chemist can be a very dangerous species. Chemists must be aware of the possible effects their products and processes might have upon the environment. Furthermore, any serious attempt to solve environmental problems must involve the extensive use of chemicals and chemical processes. There are some things that environmental chemistry is not. It is not just the same old chemistry with a different cover and title. Because it deals with natural systems, it is more complicated and difficult than “pure” chemistry. Students sometimes find this hard to grasp, and some traditionalist faculty find it impossible. Accustomed to the clear-cut concepts of relatively simple, well-defined, though often unrealistic systems, they may find environmental chemistry to be poorly delineated, vague, and confusing. More often than not, it is impossible to come up with a simple answer to an environmental chemistry problem. But, building on an ever-increasing body of knowledge, the environmental chemist can make educated guesses as to how environmental systems will behave. Chemical Analysis in Environmental Chemistry One of environmental chemistry’s major challenges is the determination of the nature and quantity of specific pollutants in the environment. Thus, chemical analysis is a vital first step in environmental chemistry research. The difficulty of analyzing for many environmental pollutants can be awesome. Significant levels of air pollutants may consist of less than a microgram per cubic meter of air. For many water pollutants, one part per million by weight (essentially 1 milligram per liter) is a very high value. Environmentally significant levels of some pollutants may be only a few parts per trillion. Thus, it is obvious that the chemical analyses used to study some environmental systems require a very low limit of detection. However, environmental chemistry is not the same as analytical chemistry, which is only one of the many subdisciplines that are involved in the study of the chemistry of the environment. Although a “brute-force” approach to environmental control, involving attempts to monitor each environmental niche for every possible pollutant, increases employment for chemists and raises sales of analytical instruments, it is a wasteful way to detect and solve environmental problems, degenerating into a mindless exercise in the collection of marginally useful numbers. Those responsible for environmental protection must be smarter than that. In order for chemistry to make a maximum contribution to the solution of environmental problems, the chemist must work toward an understanding of the nature, reactions, and transport of chemical species in the environment. Analytical chemistry is a fundamental and crucial part of that endeavor. Environmental Biochemistry The ultimate environmental concern is that of life itself. The discipline that deals specifically with the effects of environmental chemical species on life is © 2001 CRC Press LLC
environmental biochemistry. A related area, toxicological chemistry, is the chemistry of toxic substances with emphasis upon their interactions with biologic tissue and living organisms. 2 Toxicological chemistry, which is discussed in detail in Chapters 22 and 23, deals with the chemical nature and reactions of toxic sub stances and involves their origins, uses, and chemical aspects of exposure, fates, and 1.3. WATER, AIR, EARTH, LIFE, AND TECHNOLOGY In light of the above definitions, it is now possible to consider environmental chemistry from the viewpoint of the interactions among water, air, earth, life, and the anthrosphere outlined in Figure 1. 1. These five environmental"spheres"and the interrelationships among them are summarized in this section. In addition, the cha ters in which each of these topics is discussed in greater detail are designated here water and the hydrosphere Water, with a deceptively simple chemical formula of H,O, is a vitally important substance in all parts of the environment. Water covers about 70% of Earth's surface. It occurs in all spheres of the environment-in the oceans as a vast reservoir of saltwater. on land as surface water in lakes and rivers. underground as groundwater, in the atmosphere as water vapor, in the polar icecaps as solid ice, and in many segments of the anthrosphere such as in boilers or municipal water distribution systems. Water is an essential part of all living systems and is the medium from which life evolved and in which life exists Energy and matter are carried through various spheres of the environment by water. Water leaches soluble constituents from mineral matter and carries them to the ocean or leaves them as mineral deposits some distance from their sources Water carries plant nutrients from soil into the bodies of plants by way of plant roots Solar energy absorbed in the evaporation of ocean water is carried as latent heat and released inland. The accompanying release of latent heat provides a large fraction of the energy that is transported from equatorial regions toward Earths poles and owers massive storms Water is obviously an important topic in environmental sciences. Its environ- mental chemistry is discussed in detail in Chapters 3-8 Air and the atmosphere The atmosphere is a protective blanket which nurtures life on the Earth and protects it from the hostile environment of outer space. It is the source of carbon dioxide for plant photosynthesis and of oxygen for respiration. It provides the itrogen that nitrogen-fixing bacteria and ammonia-manufacturing industrial plants use to produce chemically-bound nitrogen, an essential component of life molecules As a basic part of the hydrologic cycle( Chapter 3, Figure 3. 1), the atmospher transports water from the oceans to land thus acting as the condenser in a vast solar powered still. The atmosphere serves a vital protective function, absorbing harmful ultraviolet radiation from the sun and stabilizing Earth's temperature C 2000 CRC Press llc
environmental biochemistry. A related area, toxicological chemistry, is the chemistry of toxic substances with emphasis upon their interactions with biologic tissue and living organisms. 2 Toxicological chemistry, which is discussed in detail in Chapters 22 and 23, deals with the chemical nature and reactions of toxic substances and involves their origins, uses, and chemical aspects of exposure, fates, and disposal. 1.3. WATER, AIR, EARTH, LIFE, AND TECHNOLOGY In light of the above definitions, it is now possible to consider environmental chemistry from the viewpoint of the interactions among water, air, earth, life, and the anthrosphere outlined in Figure 1.1. These five environmental “spheres” and the interrelationships among them are summarized in this section. In addition, the chapters in which each of these topics is discussed in greater detail are designated here. Water and the Hydrosphere Water, with a deceptively simple chemical formula of H2O, is a vitally important substance in all parts of the environment. Water covers about 70% of Earth’s surface. It occurs in all spheres of the environment—in the oceans as a vast reservoir of saltwater, on land as surface water in lakes and rivers, underground as groundwater, in the atmosphere as water vapor, in the polar icecaps as solid ice, and in many segments of the anthrosphere such as in boilers or municipal water distribution systems. Water is an essential part of all living systems and is the medium from which life evolved and in which life exists. Energy and matter are carried through various spheres of the environment by water. Water leaches soluble constituents from mineral matter and carries them to the ocean or leaves them as mineral deposits some distance from their sources. Water carries plant nutrients from soil into the bodies of plants by way of plant roots. Solar energy absorbed in the evaporation of ocean water is carried as latent heat and released inland. The accompanying release of latent heat provides a large fraction of the energy that is transported from equatorial regions toward Earth’s poles and powers massive storms. Water is obviously an important topic in environmental sciences. Its environmental chemistry is discussed in detail in Chapters 3-8. Air and the Atmosphere The atmosphere is a protective blanket which nurtures life on the Earth and protects it from the hostile environment of outer space. It is the source of carbon dioxide for plant photosynthesis and of oxygen for respiration. It provides the nitrogen that nitrogen-fixing bacteria and ammonia-manufacturing industrial plants use to produce chemically-bound nitrogen, an essential component of life molecules. As a basic part of the hydrologic cycle (Chapter 3, Figure 3.1), the atmosphere transports water from the oceans to land, thus acting as the condenser in a vast solarpowered still. The atmosphere serves a vital protective function, absorbing harmful ultraviolet radiation from the sun and stabilizing Earth’s temperature. © 2000 CRC Press LLC
Atmospheric science deals with the movement of air masses in the atmosphere atmospheric heat balance, and atmospheric chemical composition and reactions Atmospheric chemistry is covered in this book in Chapters 9-14 Earth The geosphere, or solid Earth, discussed in general in Chapter 15 it part of the Earth upon which humans live and from which they extract mos ir food minerals, and fuels. The earth is divided into layers, including the ron-rich inner core. molten outer core. mantle. and crust. environmental science is most concerned with the lithosphere, which consists of the outer mantle and the crust The latter is the earths outer skin that is accessible to humans. It is extremely thin compared to the diameter of the earth, ranging from 5 to 40 km thick Geology is the science of the geosphere. As such, it pertains mostly to the solid mineral portions of Earths crust. But it must also consider water, which is involved in weathering rocks and in producing mineral formations; the atmosphere and climate, which have profound effects on the geosphere and interchange matter and energy with it; and living systems, which largely exist on the geosphere and in turn have significant effects on it. Geological science uses chemistry in the form of geochemistry to explain the nature and behavior of geological materials, physics to explain their mechanical behavior, and biology to explain the mutual interactions between the geosphere and the biosphere Modern technology, for example the ability to move massive quantities of dirt and rock around, has a profound influence The most important part of the geosphere for life on earth is soil formed by the integrative weathering action of physical, geochemical, and biological processes on rock. It is the medium upon which plants grow, and virtually all terrestrial organisms depend upon it for their existence. The productivity of soil is strongly affected by environmental conditions and pollutants. Because of the importance of soil, all of Chapter 16 is devoted to it Life Biology is the science of life. It is based on biologically synthesized chemical species, many of which exist as large molecules called macromolecules. As living beings, the ultimate concern of humans with their environment is the interaction of the environment with life. Therefore, biological science is a key component of environmental science and environmental chemistr The role of life in environmental science is discussed in numerous parts of this book. For example, the crucial effects of microorg uatic chemistry ar covered in Chapter 6,"Aquatic Microbial Biochemistry. Chapter 21 "Environmental Biochemistry, addresses biochemistry as it applies to the environment. The effects on living beings of toxic substances, many of which are environmental pollutants, are addressed in Chapter 22,"Toxicological Chemistry, and Chapter 23,Toxicological Chemistry of Chemical Substances. Other chapters discuss aspects of the interaction of living systems with various parts of the environment C 2000 CRC Press llc
Atmospheric science deals with the movement of air masses in the atmosphere, atmospheric heat balance, and atmospheric chemical composition and reactions. Atmospheric chemistry is covered in this book in Chapters 9–14. Earth The geosphere, or solid Earth, discussed in general in Chapter 15, is that part of the Earth upon which humans live and from which they extract most of their food, minerals, and fuels. The earth is divided into layers, including the solid, iron-rich inner core, molten outer core, mantle, and crust. Environmental science is most concerned with the lithosphere, which consists of the outer mantle and the crust. The latter is the earth’s outer skin that is accessible to humans. It is extremely thin compared to the diameter of the earth, ranging from 5 to 40 km thick. Geology is the science of the geosphere. As such, it pertains mostly to the solid mineral portions of Earth’s crust. But it must also consider water, which is involved in weathering rocks and in producing mineral formations; the atmosphere and climate, which have profound effects on the geosphere and interchange matter and energy with it; and living systems, which largely exist on the geosphere and in turn have significant effects on it. Geological science uses chemistry in the form of geochemistry to explain the nature and behavior of geological materials, physics to explain their mechanical behavior, and biology to explain the mutual interactions between the geosphere and the biosphere.3 Modern technology, for example the ability to move massive quantities of dirt and rock around, has a profound influence on the geosphere. The most important part of the geosphere for life on earth is soil formed by the disintegrative weathering action of physical, geochemical, and biological processes on rock. It is the medium upon which plants grow, and virtually all terrestrial organisms depend upon it for their existence. The productivity of soil is strongly affected by environmental conditions and pollutants. Because of the importance of soil, all of Chapter 16 is devoted to it. Life Biology is the science of life. It is based on biologically synthesized chemical species, many of which exist as large molecules called macromolecules. As living beings, the ultimate concern of humans with their environment is the interaction of the environment with life. Therefore, biological science is a key component of environmental science and environmental chemistry The role of life in environmental science is discussed in numerous parts of this book. For example, the crucial effects of microorganisms on aquatic chemistry are covered in Chapter 6, “Aquatic Microbial Biochemistry.” Chapter 21, “Environmental Biochemistry,” addresses biochemistry as it applies to the environment. The effects on living beings of toxic substances, many of which are environmental pollutants, are addressed in Chapter 22, “Toxicological Chemistry,” and Chapter 23, “Toxicological Chemistry of Chemical Substances.” Other chapters discuss aspects of the interaction of living systems with various parts of the environment. © 2000 CRC Press LLC
The anthrosphere and technology Technology refers to the ways in which humans do and make things with materials and energy. In the modern era, technology is to a large extent the product of engineering based on scientific principles. Science deals with the discovery, explanation, and development of theories pertaining to interrelated natural phenomena of energy, matter, time, and space. Based on the fundamental knowledge of science, engineering provides the plans and means to achieve specific practical objectives. Technology uses these plans to carry out the desired objectives It is essential to consider technology, engineering, and industrial activities in udying environmental science because of the enormous influence that they have on the environment. Humans will use technology to provide the food, shelter, and goods that they need for their well-being and survival. The challenge is to interweave technology with considerations of the environment and ecology such that the two are mutually advantageous rather than in opposition to each other Technology, properly applied, is an enormously positive influence for environ- mental protection. The most obvious such application is in air and water pollution control. As necessary as"end-of-pipe" measures are for the control of air and water pollution, it is much better to use technology in manufacturing processes to prevent the formation of pollutants. Technology is being used increasingly to develop highly efficient processes of energy conversion, renewable energy resource utilization, and conversion of raw materials to finished goods with minimum generation of haz ardous waste by-products. In the transportation area, properly applied technology in areas such as high speed train transport can enormously increase the speed, energy efficiency, and safety of means for moving people and goods Until very recently, technological advances were made largely without heed to environmental impacts. Now, however, the greatest technological challenge is to reconcile technology with environmental consequences. The survival of humankind and of the planet that supports it now requires that the established two-way interaction between science and technology become a three-way relationshil including environmental protection. 1. 4. ECOLOGY AND THE BIOSPHERE The biosphere The biosphere is the name given to that part of the environment consisting of organisms and living biological material. Virtually all of the biosphere is contained by the geosphere and hydrosphere in the very thin layer where these environmental spheres interface with the atmosphere. There are some specialized life forms at extreme depths in the ocean, but these are still relatively close to the atmospheric nterface The biosphere strongly influences, and in turn is strongly influenced by, the other parts of the environment. It is believed that organisms were responsible for converting Earths original reducing atmosphere to an oxygen-rich one, a process that also resulted in the formation of massive deposits of oxidized minerals, such C 2000 CRC Press LlC
The Anthrosphere and Technology Technology refers to the ways in which humans do and make things with materials and energy. In the modern era, technology is to a large extent the product of engineering based on scientific principles. Science deals with the discovery, explanation, and development of theories pertaining to interrelated natural phenomena of energy, matter, time, and space. Based on the fundamental knowledge of science, engineering provides the plans and means to achieve specific practical objectives. Technology uses these plans to carry out the desired objectives. It is essential to consider technology, engineering, and industrial activities in studying environmental science because of the enormous influence that they have on the environment. Humans will use technology to provide the food, shelter, and goods that they need for their well-being and survival. The challenge is to interweave technology with considerations of the environment and ecology such that the two are mutually advantageous rather than in opposition to each other. Technology, properly applied, is an enormously positive influence for environmental protection. The most obvious such application is in air and water pollution control. As necessary as “end-of-pipe” measures are for the control of air and water pollution, it is much better to use technology in manufacturing processes to prevent the formation of pollutants. Technology is being used increasingly to develop highly efficient processes of energy conversion, renewable energy resource utilization, and conversion of raw materials to finished goods with minimum generation of hazardous waste by-products. In the transportation area, properly applied technology in areas such as high speed train transport can enormously increase the speed, energy efficiency, and safety of means for moving people and goods. Until very recently, technological advances were made largely without heed to environmental impacts. Now, however, the greatest technological challenge is to reconcile technology with environmental consequences. The survival of humankind and of the planet that supports it now requires that the established two-way interaction between science and technology become a three-way relationship including environmental protection. 1.4. ECOLOGY AND THE BIOSPHERE The Biosphere The biosphere is the name given to that part of the environment consisting of organisms and living biological material. Virtually all of the biosphere is contained by the geosphere and hydrosphere in the very thin layer where these environmental spheres interface with the atmosphere. There are some specialized life forms at extreme depths in the ocean, but these are still relatively close to the atmospheric interface. The biosphere strongly influences, and in turn is strongly influenced by, the other parts of the environment. It is believed that organisms were responsible for converting Earth’s original reducing atmosphere to an oxygen-rich one, a process that also resulted in the formation of massive deposits of oxidized minerals, such as © 2000 CRC Press LLC
iron in deposits of Fe,,. Photosynthetic organisms remove CO, from the atmosphere, thus preventing runaway greenhouse warming of Earths surface Organisms strongly influence bodies of water, producing biomass required for life in the water and mediating oxidation-reduction reactions in the water. Organisms are strongly involved with weathering processes that break down rocks in the geosphere and convert rock matter to soil. Lichens, consisting of symbiotic (mutually advantageous)combinations of algae and fungi, attach strongly to rocks, they secrete chemical species that slowly dissolve the rock surface and retain surface moisture that promotes rock weathering The biosphere is based upon plant photosynthesis, which fixes solar energy (hv) and carbon from atmospheric CO, in the form of high-energy biomass, represented as CH,O) CO2+H,O,CH,O)+O2(g) (14.1) In so doing, plants and algae function as autotrophic organisms, those that utilize solar or chemical energy to fix elements from simple, nonliving inorganic material into complex life molecules that compose living organisms. The opposite process biodegradation, breaks down biomass either in the presence of oxygen(aerobic respiration), (CH2O1+O2(8),CO,+ H,O (14.2) or absence of oxygen(anaerobic respiration 2ICH,O)->CO,(g)+ Ch(g) (14.3) Both aerobic and anaerobic biodegradation get rid of biomass and return carbon ioxide to the atmosphere. The latter reaction is the major source of atmospheric methane. Nondegraded remains of these processes constitute organic matter in aquatic sediments and in soils, which has an important influence on the characteristics of these solids. Carbon that was originally fixed photosynthetically forms the basis of all fossil fuels in the geosphere There is a strong interconnection between the biosphere and the anthrosphere Humans depend upon the biosphere for food, fuel, and raw materials. Human influence on the biosphere continues to change it drastically. Fertilizers, pesticides, and cultivation practices have vastly increased yields of biomass, grains, and food Destruction of habitat is resulting in the extinction of vast numbers of species, in some cases even before they are discovered. Bioengineering of organisms with recombinant DNA technology and older techniques of selection and hybridization are causing great changes in the characteristics of organisms and promise to result in even more striking alterations in the future. It is the responsibility of humankind to make such changes intelligently and to protect and nurture the biosphere Ecology Ecology is the science that deals with the relationships between living organisms with their physical environment and with each other. 4 Ecology can be approached C 2000 CRC Press llc
iron in deposits of Fe2O3. Photosynthetic organisms remove CO2 from the atmosphere, thus preventing runaway greenhouse warming of Earth’s surface. Organisms strongly influence bodies of water, producing biomass required for life in the water and mediating oxidation-reduction reactions in the water. Organisms are strongly involved with weathering processes that break down rocks in the geosphere and convert rock matter to soil. Lichens, consisting of symbiotic (mutually advantageous) combinations of algae and fungi, attach strongly to rocks; they secrete chemical species that slowly dissolve the rock surface and retain surface moisture that promotes rock weathering. The biosphere is based upon plant photosynthesis, which fixes solar energy (hn) and carbon from atmospheric CO2 in the form of high-energy biomass, represented as {CH2O}: hn CO2 + H2O ® {CH2O} + O2(g) (1.4.1) In so doing, plants and algae function as autotrophic organisms, those that utilize solar or chemical energy to fix elements from simple, nonliving inorganic material into complex life molecules that compose living organisms. The opposite process, biodegradation, breaks down biomass either in the presence of oxygen (aerobic respiration), {CH2O} + O2(g) ® CO2 + H2O (1.4.2) or absence of oxygen (anaerobic respiration): 2{CH2O} ® CO2(g) + CH4(g) (1.4.3) Both aerobic and anaerobic biodegradation get rid of biomass and return carbon dioxide to the atmosphere. The latter reaction is the major source of atmospheric methane. Nondegraded remains of these processes constitute organic matter in aquatic sediments and in soils, which has an important influence on the characteristics of these solids. Carbon that was originally fixed photosynthetically forms the basis of all fossil fuels in the geosphere. There is a strong interconnection between the biosphere and the anthrosphere. Humans depend upon the biosphere for food, fuel, and raw materials. Human influence on the biosphere continues to change it drastically. Fertilizers, pesticides, and cultivation practices have vastly increased yields of biomass, grains, and food. Destruction of habitat is resulting in the extinction of vast numbers of species, in some cases even before they are discovered. Bioengineering of organisms with recombinant DNA technology and older techniques of selection and hybridization are causing great changes in the characteristics of organisms and promise to result in even more striking alterations in the future. It is the responsibility of humankind to make such changes intelligently and to protect and nurture the biosphere. Ecology Ecology is the science that deals with the relationships between living organisms with their physical environment and with each other.4 Ecology can be approached © 2000 CRC Press LLC