1 Introduction

Contamination by organic chemicals is a global issue, and such toxic chemicals are found practically in all ecosystems because at the end of the various organic chemical lifer cycles the chemicals have either been recycled for further use or sent for disposal as waste. However, it is the inappropriate management of such waste (e.g., through haphazard and unregulated burning) poses negative impacts on human health and the environment.

This text relates to an introduction to the planned and unplanned effects of organic chemicals on the environment. Chemicals are an essential component of life, but some chemicals can severely damage the floral (plant life) and faunal (animal life) environment. There is an increase in health problems that can be partially explained by the use of chemicals, and many man-made chemicals are found in the most remote places in the environment. Specific groups of chemicals, such as biocides, pesticides, pharmaceuticals, and cosmetics, are covered by various pieces of legislation. In addition, the challenges posed by endocrine disruptors (i.e., chemicals that interfere with the hormone system causing adverse health effects) are also being addressed. However, in order to successfully manage the environment and protect the flora and fauna from such chemicals, a knowledge of chemical, specifically organic chemicals (in the context of this book), is a decided advantage.

The chief reason for studying this subject is the effects of organic chemicals not only on the environment but also on human health, which may be caused by unforeseen side effects of a chemical substance during its production, transport, use, and disposal. These effects provide the motivation for the build of scientific knowledge on the effects of organic chemicals on the floral and faunal environments. Ideally, scientists should be able to predict the possible (if not, likely) likely effects of an organic chemical directly on the environment before the chemical substance is released, enabling a more realistic appraisal to be made of any effects. A first approximation to predicting a potentially harmful organic chemical may involve the following criteria: (1) biologically nonessential, (2) toxic in larger amounts, (3) unlikely to form highly stable inert compounds in nature, (4) persistent in the environment, (5) biochemically active, and (6) environmentally mobile in any of the biogeochemical cycles.

Thus, like any technical discipline, the nonchemist is faced with understanding many new terms that are related to the chemical discipline and which need to be understood to place them in context, and this is especially true of organic chemistry. Some terms may seem familiar, but in chemistry, especially organic chemistry, the terms may have meanings that are not quite the same as when used in popular commentaries. The best and common examples are found in the area of pharmaceutical chemistry (a subdiscipline of organic chemistry) where the trade name and the alternate trade name of the pharmaceutical product bear little resemblance to any formalized system of nomenclature. In organic chemistry and, indeed, in all subdisciplines of chemistry, the terms need to have definite and specific meanings to make the subject matter understandable, and this is the raison d’être for the acceptable systems of nomenclature. One of the purposes of any system of chemical nomenclature is to provide definitions for many of these terms in a form and at a level that will make the meaning clear to those with limited backgrounds in chemistry as well as to those technical persons in other fields who need to deal with chemistry.

The International Union of Pure and Applied Chemistry (IUPAC—an international organization of chemists and national chemistry societies and the world authority on chemical nomenclature and terminology with a secretariat in Research Triangle Park, North Carolina; http://iupac.org/who-we-are/) makes the final determination of terminology and nomenclature in chemistry. Among other things, this organization authorizes and establishes systematic rules for naming compounds so that any chemical structure can be defined uniquely. Compounds are frequently called by common names or trade names, often because the IUPAC names may be long and complex and difficult to understand for the nonchemist, but the IUPAC name permits a chemist to know the structure of any chemical compound based on the rules of the terminology, while the common name or trade name requires remembering what structure goes with what name, which may be outside of the realms of chemical reality.

Engineering students, on the other hand, undergo a much different training system when compared to the students of chemistry. While some (but not all) engineering disciplines (especially the chemical engineer) may require some background knowledge of chemistry, the practicing engineer is more concerned with practical applications (such as reactor construction and operation), and there are differences in, for example, reactor novelty and reactor scale—areas that are not always pertinent to the chemist outside of laboratory chemistry. Thus, a chemist is more likely to be engaged in developing new compounds and materials using novel or new synthetic routes, while a chemical engineer is more likely to be working with existing substances. A chemist may be involved in the synthesis of a few grams of a new compound, while a chemical engineer will focus on scale up of the synthetic process in order to produce the chemical (say, on a tonnage scale) at a profit. Thus, the chemical engineer will be more concerned with heating and cooling large reaction vessels, pumps and piping to transfer chemicals, plant design, plant operation, and process optimization, while a chemist will be more concerned with establishing the parameters of the reaction from which the engineer will design the plant. However, these differences are generalizations and there is often much overlap.

To summarize: chemistry is the study of matter in its many forms as well as the manner in which these forms react with each other. Chemistry can be used to study the molecular size and the structure of the smallest of ions that exist in the human body to the much-larger scale inner workings of the core of the Earth and even with the faraway study of the chemical composition of the rocks on Mars. To understand basic chemistry is to have a healthy understanding of the complexities of the modern world. This understanding also brings forward the realization that combining chemicals released to the atmosphere by human activities can have serious health effects. And this is where an understanding of organic chemistry—which came into being as a scientific discipline in the 19th century—can play an important role in dealing with the various issues of the environment.

Thus, throughout the pages of this book, the reader will be presented with the definitions and explanations of terms related to organic chemistry and the means by which organic chemistry can be understood and used.

2 The Environment

When an organic chemical is introduced into the environment, it becomes distributed among the four major environmental compartments: (1) air, (2) water, (3) soil, and (4) biota (living organisms). Each of the first three categories can be further subdivided in floral (plant) environments and faunal (animal, including human) environments.

The fraction of the chemical that will move into each compartment is governed by the physicochemical properties of that chemical. In addition, the distribution of organic chemicals in the environment is governed by physical processes such as sedimentation, adsorption, and volatilization, and the chemicals can then be degraded by chemical and/or biological processes. Chemical processes generally occur in water or the atmosphere and follow one of four reactions: oxidation, reduction, hydrolysis, and photolysis. Biological mechanisms in soil and living organisms utilize oxidation, reduction, hydrolysis, and conjugation to degrade chemicals. The process of degradation will largely be governed by the compartment (water, soil, atmosphere, biota) in which the organic chemical is distributed, and this distribution is governed by the physical processes already mentioned (i.e., sedimentation, adsorption, and volatilization).

The impact on the environment of the changes in the chemical state of organic chemicals is only partially elucidated but will be significant in many cases. Changes in the atmospheric abundance of radiatively active gases could lead to substantial drift in the Earth's climate, including changes in temperature and precipitation, and in the frequency of occurrence of extreme events (such as hurricanes). Reduction in the ozone column abundance leads to enhanced levels of UV-B radiation at the surface with potentially harmful effects on living organisms, including phytoplankton in the ocean, and increased frequency of skin cancers affecting humans. Ecosystem damage and health problems also result from regional and global pollution. Acidic precipitation is believed to have suppressed life in several lakes of North America and Europe and, together with enhanced ozone levels, to have damaged forests in those same parts of the world.

In fact, when assessing the impact of organic chemicals on the environment, the most critical characteristics are: (1) the types of chemicals discharged, which depends on the type of industries and processes used and (2) the amount and concentration of the organic chemicals. Solid wastes (containing organic chemicals) and/or gaseous emission generated from industrial sources also contribute to the amount and concentration of organic chemicals in the environment.

This has led to the introduction of various emissions factors that are representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (such as the kilogram of pollutant per kilogram of produced product). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality and are generally assumed to be representative of long-term averages for all facilities in the source category (i.e., a population average). The general equation for emissions estimation is:

$E=A\times \mathrm{E}\mathrm{F}\times \left(1-\mathrm{E}\mathrm{R}/100\right)$

In this equation, E = emissions, A = activity rate, EF = emission factor, and ER = overall emission reduction efficiency, %.

A detailed understanding of the observed degradation in the “health of the planet” requires that atmospheric chemistry be studied in the broader context of “global change,” and that the Earth system be viewed as a nonlinear interactive system consisting of the atmosphere, the ocean, and the continental biosphere. That the chemical composition of the atmosphere has been maintained far away from the thermodynamic equilibrium conditions encountered and that the two major gases surrounding the planet are nitrogen (78%) and oxygen (21%), as opposed to carbon dioxide (CO₂) are a direct consequence of oxidation and reduction processes associated with the energy metabolism of various forms of life.

Changes encountered in the Earth system occur at different scales in time and space. For example, the formation of a tornado requires only a few minutes, while the response of the ocean to greenhouse warming is characterized by time scales of several decades. A variety of different time scales need also to be considered in the case of chemical processes in the atmosphere. For example, the chemical lifetime of a radical such as OH (which plays a key role in the chemistry of the atmosphere) is typically a few seconds, while that of most chlorofluorocarbon molecules lie in the range of several decades to a century. In the past, changes in the chemical composition of the atmosphere associated with glacial-interglacial transitions have occurred over hundreds to several thousands of years although sometimes associated with rapid fluctuations indicative of the Earth system's nonlinear nature.

2.1 Structure of the Atmosphere

The atmosphere of the Earth is largely transparent and allows incoming sunlight to reach the surface of the Earth, provided the sunlight is not reflected or absorbed by clouds. A fraction of the light that does reach the planet is absorbed, based on the degree of reflectivity of the surface. Most of the absorbed light is converted to energy, and heat is radiated back out at infrared wavelengths. Although the atmosphere allows most of the visible light through, many of the gases, such as water vapor, carbon dioxide, and methane, absorb infrared radiation, converting it to rotational and vibrational energy. This raises the energy content of the atmosphere and thus the average temperature. The more greenhouse gases present, the greater the chances of the infrared light being absorbed before it escapes into space. Thus, if all other influences are kept constant, increased levels of greenhouse gases will necessarily produce increased atmospheric temperatures. However, the impact of greenhouse gases differs based on the chemistry of the individual gases. For example, methane is much more potent than carbon dioxide because it absorbs more infrared radiation. In addition, the impact of a gas is also influenced by the lifetime of the gas in the atmosphere—water vapor falls back out quickly as precipitation, and methane is typically oxidized to carbon dioxide within decades of its appearance in the atmosphere.

Physically, the atmosphere is the thin and fragile envelope of air surrounding the Earth that is held in place around the Earth by gravitational attraction and which has a substantial effect on the environment. The total dry mass of the atmosphere (annual mean), three quarters of which is within approximately 36,000 ft of the surface, is estimated to be in excess of 5 × 10²¹ tons (Trenberth and Guillemot, 1994).

The atmosphere also contains oxygen used by most organisms for respiration and carbon dioxide used by plants, algae, and cyanobacteria for photosynthesis. The atmosphere helps protect living organisms from genetic damage by solar ultraviolet (UV) radiation, solar wind, and cosmic rays. Its current composition is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms.

In general, air pressure and density decrease with altitude in the atmosphere. However, temperature has a more complicated profile with altitude and may remain relatively constant or even increase with altitude in some regions. Because the general pattern of the temperature/altitude profile is constant and measurable by means of instrumented balloon soundings, the temperature behavior provides a useful metric to distinguish atmospheric layers. In this way, the atmosphere can be divided (called atmospheric stratification) into five main layers. Excluding the exosphere, the Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere.

Generally, the atmosphere is defined by the homosphere and the heterosphere which, in turn, are defend by whether the atmospheric gases are well mixed. The surface-based homosphere includes the troposphere, stratosphere, mesosphere, and the lowest part of the thermosphere, where the chemical composition of the atmosphere does not depend on molecular weight because the gases are mixed by turbulence. This relatively homogeneous layer ends at the turbopause found at approximately 62 miles (330,000 ft), which places it approximately 12 miles (66,000 ft) above the mesopause. Above this altitude lies the heterosphere, which includes the exosphere and most of the thermosphere. Here, the chemical composition varies with altitude. This is because the distance that particles can move without colliding with one another is large compared with the size of motions that cause mixing. This allows the gases to stratify by molecular weight, with the heavier ones, such as oxygen and nitrogen, present only near the bottom of the heterosphere. The upper part of the heterosphere is composed almost completely of hydrogen, the lightest element. The planetary boundary layer is the part of the troposphere that is closest to Earth's surface and is directly affected by it, mainly through turbulent diffusion. During the day the planetary boundary layer usually is mixed well, whereas at night it becomes stably stratified with weak or intermittent mixing. The depth of the planetary boundary layer ranges from as little as approximately 300 ft on clear, calm nights to 10,000 ft or more during the afternoon in dry regions.

However, structurally, the atmosphere consists of a number of layers that differ in properties such as composition, temperature, and pressure. From highest to lowest, the five main layers are: (1) the troposphere, (2) the stratosphere, (3) the mesosphere, (4) the thermosphere, and (5) the exosphere. Approximately three-quarters (75%,v/v) of the atmosphere's mass resides within the troposphere and is the layer within which the weather systems develop. The depth of this layer varies between 548,000 ft at the equator and 23,000 ft over the polar regions. The stratosphere extends from the top of the troposphere to the bottom of the mesosphere, contains the ozone layer which ranges in altitude between 49,000 and 115,000 ft, and is where most of the UV radiation from the Sun is absorbed. The top of the mesosphere ranges from 164,000 to 279,000 ft and is the layer, wherein most meteors burn up. The thermosphere extends from 279,000 ft to the base of the exosphere at approximately 2,300,000 ft altitude and contains the ionosphere, a region where the atmosphere is ionized by incoming solar radiation.

2.1.1 The Troposphere

The troposphere is the lowest layer of atmosphere of the Earth and the layers to which changes can greatly influence the floral and faunal environments. Atmosphere of the Earth: it extends from Earth's surface to an average height of approximately 12 km although this altitude actually varies from approximately 30,000 ft at the polar regions to 56,000 ft) at the equator, with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e., a layer of relatively warm air above a colder one), and in others by a zone which is isothermal with height.

Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e., Earth's surface) is typically the warmest section of the troposphere, which promotes vertical mixing. The troposphere contains approximately 80% of the mass of the atmosphere of the Earth. The troposphere is denser than all its overlying atmospheric layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of the total mass of the atmosphere is located in the lower 18,000 ft of the troposphere.

Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation although very tall cumulonimbus thunder clouds can penetrate the tropopause from below and rise into the lower part of the stratosphere. Most conventional aviation activity takes place in the troposphere, and it is the only layer that can be accessed by propeller-driven aircraft.

In addition, the atmosphere is generally described in terms of layers characterized by specific vertical temperature gradients. The troposphere is characterized by a decrease of the mean temperature with increasing altitude. This layer, which contains approximately 85–90% (v/v) of the atmospheric mass, is often dynamically unstable with rapid vertical exchanges of energy and mass being associated with convective activity. Globally, the time constant for vertical exchanges is of the order of several weeks. Much of the variability observed in the atmosphere occurs within this layer, including the weather patterns associated, for example, with the passage of fronts or the formation of thunderstorms. The planetary boundary layer is the region of the troposphere where surface effects are important, and the depth is on the order of 3300 ft but varies significantly with the time of day and with meteorological conditions. The exchange of chemical compounds between the surface and the free troposphere is directly dependent on the stability of the boundary layer.

2.1.2 The Stratosphere

Above the troposphere, the atmosphere becomes very stable, as the vertical temperature gradient reverses in a second atmospheric region—the stratosphere—which extends from the top of the troposphere at approximately 39,000 ft above the surface of the Earth to the stratopause at an altitude of approximately 164,000–180,000 ft. The atmospheric pressure at the top of the stratosphere is approximately 1/1000th the pressure at sea level, which contains 90% of the atmospheric ozone. A typical residence time for material injected in the lower stratosphere is 1–3 years. The stratosphere is the second-lowest layer of atmosphere of the Earth and lies above the troposphere and is separated from it by the tropopause.

The stratosphere contains the ozone layer, which is the part of atmosphere that contains relatively high concentrations of that gas. In this layer ozone concentrations are approximately 2–8 ppm, which is much higher than in the lower atmosphere but still very small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from approximately 49,000 to 115,000 ft, though the thickness varies seasonally and geographically. Approximately 90% (v/v) of the ozone in Earth's atmosphere is contained in the stratosphere.

The stratosphere defines a layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of UV radiation from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature is typically on the order of − 60°C (− 76°F) at the tropopause, the top of the stratosphere is much warmer and may be near 0°C (32°F). The stratospheric temperature profile creates very stable atmospheric conditions, so the stratosphere lacks the weather-producing air turbulence that is prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather. However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest, and this is the highest layer that can be accessed by conventional jet-powered aircraft.

2.1.3 The Mesosphere

The mesosphere is the third highest layer of atmosphere and occupies the region above the stratosphere and below the thermosphere. This layer extends from the stratopause at an altitude of approximately 160,000 ft to the mesopause at approximately 260,000–80,000 ft above sea level. Temperatures drop with increasing altitude to the mesopause that marks the top of this middle layer of the atmosphere. It is the coldest place on Earth and has a temperature on the order of − 85°C (− 120°F).

Just below the mesopause, the air is so cold that even the very scarce water vapor at this altitude can be sublimated into polar-mesospheric noctilucent clouds. These are the highest clouds in the atmosphere and may be visible to the naked eye if sunlight reflects off them approximately an hour or two after sunset or a similar length of time before sunrise. They are most readily visible when the Sun is around 4–16 degrees below the horizon. The mesosphere is also the layer where most meteors burn up upon atmospheric entrance.

2.1.4 The Thermosphere

The thermosphere is the second highest layer of Earth's atmosphere and extends from the mesopause (which separates it from the mesosphere) at an altitude of approximately 260,000 ft up to the thermopause at an altitude that ranges from 1,600,000 to 3,300,000 ft. In the thermosphere, the temperature increases to reach maximum values that are strongly dependent on the level of solar activity. Vertical exchanges associated with dynamical mixing become insignificant, but molecular diffusion becomes an important process that produces gravitational separation of species according to their molecular or atomic weight.

The uneven distribution of radiative heating in the Earth system produces a meridional circulation of air (circulation in the north-south direction), with rising motion at low latitudes and sinking motion at mid- and high latitudes. This meridional overturning of air masses is modified substantially by the Earth's rotation, especially outside the tropics, where the mean circulation is nearly circumpolar (along latitude circles). A small meridional component, however, transfers heat and transports trace constituents from equatorial to polar regions. The zonal flow (circulation in the west-east direction) is perturbed by orographic features at the Earth's surface (e.g., mountains) and latent heat release associated with the formation of clouds, as well as synoptic weather systems in the troposphere. Chemical constituents (including organic chemicals) are redistributed in the atmosphere by transport processes caused by such dynamical disturbances.

The height of the thermopause varies considerably due to changes in solar activity. Because the thermopause lies at the lower boundary of the exosphere, it is also referred to as the exobase. The lower part of the thermosphere, from 260,00 to 1,800,000 ft above the surface of the Earth surface, contains the ionosphere.

The ionosphere is a region of the atmosphere that is ionized by solar radiation and is responsible for auroras (the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere). The ionosphere increases in thickness and moves closer to the Earth during daylight and rises at night allowing certain frequencies of radio communication a greater range. During daytime hours, it stretches from approximately 160,000 to 3,280,000 ft and includes the mesosphere, thermosphere, and parts of the exosphere. However, ionization in the mesosphere largely ceases during the night, so auroras are normally seen only in the thermosphere and lower exosphere. The ionosphere forms the inner edge of the magnetosphere. It has practical importance because it influences, for example, radio propagation on Earth.

The temperature of the thermosphere gradually increases with height. Unlike the stratosphere beneath it, wherein a temperature inversion is due to the absorption of radiation by ozone, the inversion in the thermosphere occurs due to the extremely low density of its molecules. The temperature of this layer can rise as high as 1500°C (2700°F), though the gas molecules are so far apart that its temperature in the usual sense is not very meaningful. This layer is completely cloudless and free of water vapor. However nonhydrometeorological phenomena such as the aurora borealis and aurora australis are occasionally seen in the thermosphere.

The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 328,000, or 1.57% of the radius of the Earth's radius is often used as the border between the atmosphere and outer space. The International Space Station orbits in this layer, between 1,200,000 and 1,373,000 ft.

2.1.5 The Exosphere

The exosphere is the outermost layer of Earth's atmosphere (i.e., the upper limit of the atmosphere) and extends from the exobase, which is located at the top of the thermosphere. The exosphere begins variously from approximately 2,300,000 to 3,280,000 ft above the surface, where it interacts with the magnetosphere, to space. Each of the layers has a different lapse rate, defining the rate of change in temperature with height. Initial atmospheric composition is generally related to the chemistry and temperature of the local solar nebula during planetary formation and the subsequent escape of interior gases.

The escape to space of hydrogen atoms (estimated to be on the order of 25,000 tons/year) from the exosphere, the atmospheric region in contact with the interplanetary medium, has most certainly contributed to substantial changes in the chemical composition of the atmosphere over geological history. This escape flux increases due to the increase in methane abundance (Ehhalt, 1986).

The exosphere layer is mainly composed of extremely low densities of hydrogen, helium, and several heavier molecules including nitrogen, oxygen, and carbon dioxide closer to the exobase. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another. Thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. The exosphere contains most of the satellites orbiting Earth.

2.1.6 Composition

The three major constituents of air, and therefore of Earth's atmosphere, are nitrogen, oxygen, and argon. Thus, the atmosphere of the Earth is a mixture of chemical constituents—the most abundant of them are nitrogen (N₂, (78%, v/v)) and oxygen (O₂, (21%, v/v)). These gases, as well as the noble gases (argon, neon, helium, krypton, xenon), possess very long lifetimes against chemical destruction and, hence, are relatively mixed well throughout the entire homosphere (below approximately 295,000 ft altitude). Minor constituents, such as water vapor, carbon dioxide, ozone, and many others, also play an important role despite their lower concentration. These constituents influence the transmission of solar and terrestrial radiation in the atmosphere and are therefore linked to the physical climate system; they are key components of biogeochemical cycles; in addition, they determine the oxidizing capacity of the atmosphere and, hence, the atmospheric lifetime of biogenic and anthropogenic traces gases.

Water vapor accounts for approximately 0.25% (w/w) of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by volume in the coldest portions of the atmosphere to as much as 5% by volume in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor). The remaining gases are often referred to as trace gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone. The spatial and temporal distribution of chemical species in the atmosphere is determined by several processes, including surface emissions and deposition, chemical and photochemical reactions, and transport. Surface emissions are associated with volcanic eruptions, floral and faunal activity on the continents as well as in the ocean, as well as anthropological activity such as biomass burning, agricultural practices, and industrial activity. Chemical conversions are achieved by a multitude of reactions whose rate constants are measured in the laboratory. Transport is usually represented by large-scale advective motion (displacements of air masses in the quasi-horizontal direction), and by smaller scale processes, including convective motions (vertical motions produced by thermal instability and often associated with the presence of large cloud systems), boundary layer exchanges, and mixing associated with turbulence. Wet deposition results from precipitation of soluble species, while the rate of dry deposition is affected by the nature of the surface (e.g., type of soils, vegetation, ocean, etc.).

2.1.7 Chemical Activity

Chemical compounds released at the surface by natural and anthropogenic processes are oxidized in the atmosphere before being removed by wet or dry deposition. Key chemical species of the troposphere include organic compounds such as methane and nonmethane hydrocarbons as well as oxygenated organic species and carbon monoxide, nitrogen oxides (which are also produced by lightning discharges in thunderstorms), as well as nitric acid and peroxyacetyl nitrate (PAN, an unstable secondary pollutant present in photochemical smog and which decomposes into peroxyethanoyl radicals and nitrogen dioxide):

Other chemical species include: hydrogen compounds (specifically the hydroxyl radical, OH, and the hydroperoxy radical, HO₂, as well as hydrogen peroxide, H₂O₂, and ozone, O₃) and sulfur compounds [dimethyl sulfide (DMS), sulfur dioxide, SO₂, and sulfuric acid, H₂SO₄].

The hydroxyl radical (OH) deserves additional consideration since it has the capability of reacting with and efficiently destroying a large number of organic chemical compounds, and hence of contributing directly to the oxidation capacity (reactivity) of the atmosphere. Ozone also plays an important role in the troposphere—together with water vapor ozone is the source of the hydroxy radical and, in addition, it contributes to climate forcing—climate forcing is any influence on climate that originates from outside the climate system itself and is a major cause of climate change, which includes the temperature rise of the earth during an interglacial period which exists at the present. The presence of this gas in the troposphere results not only from the intrusion of ozone-rich stratospheric air masses through the tropopause; it is also produced by photochemical reactions involving hydrocarbon derivatives, nitrogen oxides (NO_x), and carbon monoxide (CO). One major question is to what extent the oxidizing capacity of the atmosphere has changed as a result of human activities. Finally, the release of sulfur compounds at the surface of the Earth surface and the subsequent oxidation of the sulfur compounds in the atmosphere leads to the formation of small liquid or solid particles that remain in suspension in the atmosphere. These aerosol particles affect the radiative balance of the atmosphere directly, by reflecting and absorbing solar radiation, and indirectly, by influencing cloud microphysics. The release to the atmosphere of sulfur compounds has increased dramatically, particularly in regions of Asia, Europe, and North America as a result of human activities, specifically coal combustion (Speight, 2013).

Gases that are not rapidly destroyed (such as by interaction with the hydroxyl radical) or removed by clouds and rain in the troposphere are transported upward into the stratosphere, where they are dissociated by short-wave UV radiation to produce fast-reacting radicals. Chlorofluorocarbons or nitrous oxide are examples of such long-lived gases that, when subject to photolysis in the stratosphere, provide a source of chlorine or nitrogen oxides, respectively. Such fast-reacting radicals initiate catalytic cycles that lead to the destruction of ozone, before being converted into chemical reservoirs that are gradually removed from the stratosphere. The abundance of ozone results from a delicate balance between these destruction mechanisms and the natural production of O₃ through the photolysis of molecular oxygen. There is strong evidence that suggests that the depletion of stratospheric ozone observed over the past decade is the direct consequence of the release in the atmosphere of industrially manufactured chlorofluorocarbons.

Filtered air includes trace amounts of many other chemical compounds. Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen, and spores, sea spray, and volcanic ash. Various industrial pollutants also may be present as gases or aerosols, such as chlorine, (elemental or in compounds), fluorine compounds, and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO₂) may be derived from natural sources or from industrial air pollution. By volume, dry air contains (subject to minor rounding of the data) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases (Table 1.1). Air also contains a variable amount of water vapor, approximately 1% (v/v) at sea level and 0.4% (v/v) throughout the entire atmosphere. Air content and atmospheric pressure vary at different layers, and air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in the troposphere.

Table 1.1

Composition of the Atmosphere

Gas	Formula	Volume (ppm)	Volume (%)
Nitrogen	N2	80,840	78.084
Oxygen	O2	209,460	20.946
Argon	Ar	9340	0.9340
Carbon dioxide	CO2	397	0.0397
Neon	Ne	18.18	0.001818
Helium	He	5.24	0.000524
Methane	CH4	1.79	0.000179
Water vapora	H2O	10–50,000(D)	0.001–5(D)

^a Water vapor is not included in above dry atmosphere and is approximately 0.25% (v/v) over the full atmosphere but does vary considerably.

3 Organic Chemistry and the Environment

The 20th century came into being in much the same manner as the 19th century ended insofar as there was a continuation of the less-than-desirable disposal methods for chemical waste, which included gaseous waste, liquid waste, and solid waste. As the 20th century evolved, the use and disposal of chemicals expanded by several orders of magnitude and this expansion seemed to be unstoppable. In fact, it was not only industrial waste that was disposed of in a manner that was dangerous-to-the-environment but also the disposal of household chemicals (in considerable quantities when measured on a city-wide basis) that were used to paint, clean, and maintain homes and gardens. At the time, there was not the realization that many of these products were toxic to the flora and fauna (including humans) of the environment, whether or not they are used or disposed of improperly. However, during the latter quarter of the 20th century and by beginning of the 21st century, there came the realization that chemicals (some in large concentrations, other in small concentrations) were toxic and the unabated disposal of chemicals had to change. This awakening of an (almost global) environmental consciousness led to the legislation in many countries that chemical disposal must be organized and carried out by legislatively sanctioned methods, and the unabated and dangerous disposal of chemicals must cease.

The chemicals industry (which, within the context of this book, includes the fossil fuels industry) and its products provide many real and potential benefits, particularly related to improving and sustaining human health and nutrition as well as, on the economic side, financial capital through new opportunities for employment. At the same time that benefits accrue, the production and use of chemicals creates risks to the environment at all stages of the production cycle. The generation and intentional and unintentional release of the produced chemicals (and the process by-products) has contributed to environmental contamination and degradation at multiple levels—local, regional, and global—and in many instances the impact will, more than likely, continue to be felt for generations.

As a result, it is now (some observers would use the word finally instead of the word now) recognized and legislated that any process waste (including hazardous and nonhazardous wastes) should never be discarded without proper guidance and authority. The effects of these errant, irresponsible, irregular (and often illegal) methods of disposal were being observed in the atmosphere (the occurrence of smog in cities such as London and Manchester in the late 1950s is often cited as examples), the waterways (dead fish floating in rivers, streams, lakes, and oceans), and landfills (or anywhere that the waste was dumped on to solid ground (leading to objectionable odors and poisonous run-off material). Many forms of disposal (which are considered to be illegal by modern disposal standards or protocols) continued unchecked and unmonitored during the early part of the 20th century. Then in the 1950s, Rachel Carson (a marine biologist) wrote pamphlets on conservation and natural resources and edited scientific articles, but in her free time turned her government research into lyric prose, first as an article Undersea (1937, for the Atlantic Monthly), and then in a book, Under the Sea-Wind (1941) followed by The Sea Around Us in 1952, The Edge of the Sea in 1955, and Silent Spring in 1962. In her book Silent Spring, Carson warned of the dangers to all natural floral and faunal ecosystems from the misuse of pesticides such as DDT (dichlorodiphenyltrichloroethane).

In Silent Spring, Carson also questioned the scope and direction of modern science, which many observers consider her (justifiably) to be the initiator of the modern environmental movement (Carson, 1962; Lear, 2015). The book dealt with many environmental problems associated with the unmonitored use chlorinated pesticides and initiated an extensive examination approximately safety of many different types of chemicals and the disposal methods of unwanted chemicals, waste chemicals, and chemical byproducts that can cause environmental pollution. As a result, the use of DDT (and similar pesticidal chemicals) was not only initially discouraged but was banned in 1972.

Following from this, and with the establishment of environmental protection agencies or departments by various levels, for example, local, state, and federal governments (in the United States and many other countries), serious consideration was given to the need for investigation of the methods by which chemicals were affecting the environment. As a result, methods were devised for handling chemical wastes with minimal effect on the environment (Carson and Mumford, 1988, 1995). In fact, during the last five decades it has become increasingly clear that the chemical and allied industries (including the pharmaceutical industries and the fossil fuel industries) can cause serious environmental problems if methods of disposal for unwanted chemicals and chemical wastes remain unchecked. As a result, many of these industries generate large amounts of chemical waste and have been subjected to strict legislation that requires minimization or, preferably, elimination of the various waste streams (Sheldon, 2010).

Furthermore, because of the importance of chemical contamination of the environment which involves a study of the effects of chemicals on the environment, the recent subdiscipline of environmental chemistry with the subcategories of environmental organic chemistry and environmental inorganic chemistry has arisen and evolved. Both environmental organic chemistry and environmental inorganic chemistry are now a component (optional or otherwise) of many chemistry degree courses in universities and are included in environmental science courses and environmental engineering courses as elements of increasing substance. These relatively new disciplines focus on the various environmental factors which govern the processes that determine the fate of organic chemicals and inorganic chemicals in ecosystems. The information discovered is then combined with the properties of the compound and applied to a quantitative assessment of the environmental behavior of a wide variety of chemicals (Mackay et al., 2006). Furthermore, research opportunities in environmental chemistry and environmental engineering have continued to be an educational growth area as new programs evolve to respond to local, national, regional, or global problems of various environmental issues at both fundamental and applied levels. In concert with these educational advances, the chemical industry is faced ever-increasing challenges from regulations pertaining to the environmental safety and environmental acceptability of its products.

Prior to the environmental revolution and during its infancy, organic chemistry related to the study of compounds from living organisms and as the subject matter evolved, the meaning was expanded to include the chemistry of carbon compounds. Relating to the current theme of this book, organic chemistry (a subdiscipline of chemistry) is the chemistry of carbon compounds—generally excluding the chemistry of carbon monoxide (CO) and carbon dioxide (CO₂)—and involves the scientific study of the structure, properties, and reactions of organic compounds, that is, matter in its various forms that are based on carbon atoms.

Thus, organic chemistry is the chemistry of carbon, an element that forms strong chemical bonds to other carbon atoms as well as to many other elements such as hydrogen, nitrogen, oxygen, sulfur, the halogens (fluorine, chlorine, bromine, and iodine), as well as a variety of different metals, such as nickel, vanadium, iron, and copper that occur as organometallic derivatives in many crude oils (Reynolds, 1998; Speight, 2014). Carbon always forms four covalent bonds (four shared pairs of electrons) that may be present as four single bonds per atom, or two single bonds and one double bond, or one single bond and one triple bond. With the ability of carbon to bond in different ways, an important part of organic chemistry concerns the structure of compounds. Organic chemistry is important because the vital biological molecules in living systems are largely organic compounds and, because of its versatility in forming covalent bonds, the number of known carbon compounds can only be conservatively estimated to be on the order of one million, possibly more. Furthermore, in the context of this book, environmental organic chemistry addresses the influence of organic chemicals on the environment which includes: (1) the study of the structure of organic compounds, (2) the physical properties of organic compounds, (3) the chemical properties of organic compounds, and (4) the reactivity or organic compounds with the goal of understanding the behavior of organic compounds not only in the in the pure form (when possible) but also in aqueous and nonaqueous solutions as well as the chemistry of complex mixtures to reflect the manner in which such chemicals exist and react in the environment.

For example, the presence of one or more functional groups (specific groups, moieties) consisting of atoms or bonds within organic molecules that are responsible for the characteristic chemical reactions and behavior of those organic molecules and which can dictate (1) the reactivity of the compound, (2) the manner by which the compound reacts to external influences, (3) the manner by which the chemical can dissipate into the atmosphere, (4) the solubility of the compound in aqueous systems, as well as (5) the manner by which the compound can adhere to, and remain in, the soil.

Simple, physical properties are properties that do not change the chemical nature of matter, while chemical properties are properties that do change the chemical nature of matter. Examples of physical properties are: color, smell, freezing point, boiling point, melting point, infra-red spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets, opacity, viscosity, and density. In addition, measuring each of these properties will not alter the basic nature of the substance. Examples of chemical properties are: heat of combustion, reactivity with water, acidity-alkalinity, and electromotive force. The more properties that can be used to identify a chemical, the better the nature of the chemical becomes known. These properties can to understand how this substance will behave under various conditions. In concert with the chemical properties physical properties of organic compounds, the physical properties that are typically of interest to the environmental scientist and environmental engineer include both quantitative and qualitative properties (Table 1.2).

Quantitative information includes the melting point (and the solidification point or the freezing point), the boiling point, as well as the tendency of the compound to evaporate under ambient conditions while qualitative properties include odor, solubility, and color. For example, organic compounds typically have recordable melting points and/or boiling points, but, in contrast, many mixtures will melt or boil over a range depending upon the composition of the mixture. In addition, inorganic chemicals generally melt (often at extremely high temperatures), and many do not exhibit recordable boiling points and tend to undergo thermal degradation. For organic chemicals, the melting point and the boiling point can provide valuable information not only on the purity and identity of an organic compound as well as a chemical assessment of the behavior of the compound in the environment. Furthermore, some organic compounds have a sublimation point, the temperature at which the organic compound undergoes sublimation (evaporation without melting thereby omitting the intermediate liquid phase).

As an example of the use of properties and the forewarning that properties can offer in terms of behavior, p-dichlorobenzene (para-dichlorobenzene, 1,4-dichlorobenzene, ClC₆H₄Cl), which is used as an insecticide for moth control, contains two chlorine atoms that are located in positions directly opposite to each other in the benzene ring and which sublimes (passes from the solid phase to the gas phase without the intervention of a liquid phase) readily at or near room temperature (Rossberg et al., 2006):

Thus, this compound can give the appearance of disappearing over a short period of time (depending upon the amount of the compound) which may present the false impression that the compound does not harm the environment but merely evaporates. Nevertheless, the compound after sublimation is most likely to condense on the nearest cool surface, thereby giving rise to further pollution problems.

In addition, solubility of organic compounds in water as well as solubility in organic solvents is also important properties that must be acknowledged. Organic compounds tend to dissolve in organic solvents such as ether (diethyl ether, C₂H₅OC₂H₅) and in paraffinic solvents such as the various types of petroleum-derived naphtha and kerosene as well as in a variety of aromatic solvents (aromatic naphtha, aromatic kerosene). Solubility in the different solvents depends not only upon the solvent type but also on the type and number of the functional groups present in the organic compound. Thus, nonacidic and nonbasic (neutral) organic compounds tend to be hydrophobic (water-hating, water repellant) insofar as they are less soluble in water than in organic solvents. Exceptions include organic compounds that contain polar (ionizable) functions (functional groups that can be converted into positively- or negatively charged ions) as well as low-molecular-weight alcohol (ROH) derivatives, amine (RNH₂) derivatives, and carboxylic acid (RCO₂H) derivatives.

Finally, modern organic chemistry is a dynamic discipline and it is evolving rapidly, and the concepts are applicable to all aspects of organic chemistry, especially the organic chemistry of the environment. Thus, organic compounds can be described in terms of simple carbon-based molecular structures in which atoms are held together by chemical bonds. This concept of organic chemistry has persisted for more almost 200 years and seems unlikely to be superseded, no matter how much the discipline is refined and modified (Smith, 2013).

4 Use and Misuse of Chemicals

The use of chemicals for domestic and commercial purposes increased phenomenally during the 19th and 20th centuries but although brining benefits also had negative impacts on human health and safety as well as on the integrity of terrestrial and marine ecosystems and on air and water quality. The general lack of definitive plans to manage the use of chemicals threatened the sustainability of the environment. Whatever the chemical, there are risks to its use—known and unknown—and some chemicals, including heavy metals, persistent organic pollutants, and PCBs present risks that have been known for decades. On the other hand, there has been the release of chemicals into the environment, many of which are long lived and transform into by-products whose behavior, synergies, and impacts are not well known (Jones and De Voogt, 1999).

Nevertheless, organic chemicals are a significant contributor to the human lifestyle (Appendix: Table A1) and as long as there is sound chemical management across the lifecycle of a chemical—from extraction or production to disposal—it is possible (under current legislative guidelines) and essential to avoid risks to the floral and faunal environments. Nevertheless, there are always two sides to the statement: chemicals are a blessing but also can be curse. Just as there are benefits to the use of chemicals, they must be with respect so as to minimize any harmful impact from exposure of the environment to the organic chemicals.

Thus, organic chemicals while being considered to be the chemicals of life can also be the chemicals of harm. Understanding organic chemistry, perhaps not to the extent of the dyed-in-the-wool organic chemist, is a part of understanding the use and effects of organic chemicals. To many nonchemists, chemicals tend to be seen as frightening, and (often without justification) the general perception is that all chemicals are dangerous and use of chemicals should be avoided—as a by-the-way, water is a chemical. The important aspect of organic chemicals is that they are essential for life, but there is the necessity to treat organic chemicals with respect and caution. Some organic chemicals can be hazardous and should always be handled with care, as evidenced by the advisory (warning) statements on the packaging of the various chemicals which are presented as a matter of safety. The risk faced from exposure to an organic chemical is based on the intrinsic danger multiplied by the exposure to the chemical both in terms of the amount of the chemical and the time of exposure. A simple example is the chemical curare (an alkaloid—a nitrogen containing natural product), which is a common name for various plant extracts which are used as arrow-tip poisons (often fatal) originating in Central America and South America. On the other hand, it has also been used as a muscle relaxant (in extremely small dosages) but with some risk to the patient. Nevertheless, it has been possible for the medical community to adjust the dosage from a death-dealing quantity (on an arrowhead) to a medicinal quantity under strict supervision (EB, 2015).

Organic chemicals, and their various derivatives, are widely used in many sectors of the modern world including the chemicals industry, the fossil fuels industry, agriculture, mining, water purification, and public health. However, not only the dedicated use of organic chemicals but also the production, storage, transportation, and removal of these substances can pose risks to the environment if safe handling protocols are not followed. Developing an effective management system for organic chemicals requires addressing the specific challenges that arise because of the individual chemicals and chemical mixtures because the irregular management of obsolete organic chemicals and chemical mixtures, stockpiles, and waste presents serious threats to the environment. As the use of organic chemicals and production increases, chemical management, which already has limited resources and capacity, will be further constrained and overburdened and may fail if not regulated. Measures and systems need to be developed to reduce exposure to negative impacts and to reduce vulnerability of the environment.

The initial moves in the development of an efficient management system is to ensure that there are education programs that prepare professionals to enter the field of environmental technology as well education programs that prepare individuals to meet the challenges of environmental management in the forthcoming decades (Speight and Singh, 2014). There is no single discipline by which these challenges can be met—young professionals should be skilled in the sciences, the engineering technologies, and the relevant subdisciplines that enable them to cross-over from one discipline to another as the occasion demands.

Along with the increased use of chemicals, specifically the use of organic chemicals in the context of this book has come the realization that many widely used organic compounds are more toxic to the environment than was previously suspected. Some are carcinogenic and some may contribute to the destruction of the ozone layer in the upper atmosphere, which protects all life from the sun's strong UV radiation, while other organic chemicals are concentrated and persist in living tissue with an, as yet, unknown effect. Nonetheless, the modern world has adapted to the use of synthetic organic chemicals, and there are continuing debates that crude oil the largest source of organic chemicals—while in good supply at the present time—may be in short supply in the next 50–100 years, and there will be the need to rely on alternate sources of energy, which are not immune from causing damage to the environment (Speight, 2011, 2014; Lee et al., 2014; Speight and Islam, 2016). There have been several suggestions—not taken in any serious form so far—that coal once again become king in terms of chemicals production. Thus, in order to develop an effective management system that protects the environment from organic chemicals, there is the need to recognize that the modern world relies on both natural and synthetic chemicals which can be tailored to serve specific purposes. In fact, the gasification of coal (or, for that matter, other carbonaceous material such as biomass) to produce synthesis gas (a mixture of carbon monoxide and hydrogen) is an established process from which a variety of organic chemicals can be synthesized (Davis and Occelli, 2010; Chadeesingh, 2011; Speight, 2013).

In fact, the rise of industry has been centered on the development of organic chemistry that has resulted, for example, in the creation of synthetic polymers for the more effective and efficient production of goods. Occasionally, organic chemicals are actually designed to damage faunal life (in theory, excluding human life), and in so doing, they offer benefits to humanity. For example, pesticides and herbicides are designed to destroy various organisms so that crop yields may be higher while antibiotics are designed to destroy harmful bacteria. However, although chemicals supply a variety benefits, they also present the potential for misuse—stepping aside from the issue of organic chemicals (pesticides, herbicides, and fungicides) and the environment to the more specific issues of chemicals and the human environment, drugs such as morphine (which affect the human fauna of the Earth) is an important multiuse organic chemical and is used as a pain-killer in medicine as well as in, as well as to create other pharmaceutical derivatives such as codeine, another pain-killer.

In addition, heroin is an opioid drug that is synthesized from morphine, a naturally occurring substance extracted from the seed pod of the Asian opium poppy plant. Heroin, the (the 3,6-diacetyl ester of morphine:

Heroin usually appears as a white or brown powder or as a black sticky substance (black tar heroin). In fact, the illegal production of heroin remains an incredibly profitable industry, at the expense of the wellbeing of thousands of addicts. When absorbed into the brain, both codeine and heroin are converted back into morphine. However, heroin crosses the blood-brain barrier more rapidly than either morphine or codeine, thus producing a more immediate and potent response. While there are risks accompanying the use of morphine due to its addictive potential, the risks are even higher in the case of heroin. Nevertheless, a ban on opium production is not a plausible response to this problem because the opium poppy is used for a spectrum of purposes. Therefore, the regulation of opium and the production of morphine is an important and difficult task, one which cannot be ignored if it is hoped to lessen the burden of drug addiction in many nations. Another drug, the chemical known as methamphetamine:

is a highly addictive synthetic drug, derived from a medicinal plant also causes severe addition and alteration of man behavior. Thus, the same knowledge that has led to cures and treatments for disease has also accelerated illegal drug use (typically misuse of organic chemicals). Similarly, important industrial chemicals can be used to create chemical agents of warfare agents, and, as a result, the response to the abuse of chemicals, known as the Chemical Weapons Convention (http://www.cwc.gov/), seeks to monitor and prevent the development of chemical weapons.

The preceding paragraphs are used as attention-getters to demonstrate how easily organic chemicals (especially, in the human context) in the form of illegal drugs can be misused, and the same reasoning can be applied to the misuse of other organic chemicals that bring harm to the environment. As the knowledge and understanding of organic chemicals increases—as well as the variety of routes of synthesis of these chemicals—so does the ease of synthesis and production of such compounds. This makes understating the different aspects of the use of these chemicals a greater task than ever, and the legislated regulation of multiuse chemicals become an essential part of the organic chemicals industry. However, as an understanding of organic chemistry increases, so must a sense of responsibility related to the use of organic chemicals as well as the effects of these chemicals on the floral and faunal environments, and the various protocols for the disposal of organic chemicals. Laws relating to the regulation and use of such chemicals must be vigorously policed and updated, especially since there is the continual search for new synthetic routes to the chemicals (accompanied by the efforts of the would-be multiuse chemical abusers) so as to avoid being outstripped by the development of science and suffer the resulting environmental consequences of this negligence.

When an event occurs that is detrimental to the floral and faunal environments, the allocation of chemical responsibility is often a difficult process. The issues relating to the responsibility for the development and dispersal of organic chemicals continue to be debated. Many observers would argue that the users are to blame as are the producers and the chemists who discovered the synthesis reactions by which the chemicals are produced. However, given that the use and disposal of chemicals is a global problem, the responsibility to deal with the problem must fall to policy makers in the various levels of government (local, state, and federal) who are involved in the creation of regulatory laws, it is important to create codes of conduct to guide behavior and actions with regard to this complex problem. In addition, governments who fail to create responsible regularity laws must also share some of the blame for the misuse of chemicals. The politicians cannot consider themselves immune from blame when the necessary laws are not passed or are not policed.

There are two types of codes related to the use/misuse of organic chemicals and their subsequent disposal: (1) enforceable codes of conduct and (2) aspirational codes of conduct. An enforceable codes of conduct deals with the necessary protocols for regulation and enforcement of the code, while an aspirational code of conduct presents the ideals of performance so that those bound to the code may be reminded of their obligations to perform ethically and responsibly. Nevertheless, there are many observers who are in serious doubt about the practical effectiveness of such codes, which may even prescribe ambiguous (and often unattainable) ideals which can be circumvented if the producers and/or the users of the chemicals wish to do so.

Typically, the value of a code of conduct is usually most clearly evident to the creators and writers of the code. Those who must consider every word and phrase included in the code must also explain the importance of expressing the meaning of the code in an unambiguous, straight-forward, understandable, and effective way. Furthermore, it is also essential to involve the various groups with different interests and perspectives at the time when the code is being formulated so as to inform the various groups of the issues addressed in the code as well as to remind all participants and the users of the responsible use of organic chemicals. In doing so, a code of conduct can be written to be highly effective which should assist the scientists, the engineers, and the public of the issues at hand. From this understanding should come the responsibilities and the guidelines for each party to act in a responsible and ethical manner.

Thus, effective management of organic chemicals to protect all types of flora and fauna from all chemicals should carry with it the reminder that to ensure the proper use of chemistry and chemicals there is the need to develop and hold to strict codes of conduct that establish guidelines for ethical scientific development and protection of the environment.

5 Chemicals in the Environment

Organic chemicals and organic chemical waste (such as organic hazardous waste) are pose substantial or potential threats to the floral and faunal environments. In the United States, the treatment, storage, and disposal of any type of waste (but for the purposes of this text, organic waste and organic hazardous waste are regulated under the Resource Conservation and Recovery Act (RCRA). In this Act, which hazardous wastes are defined 40 CFR 261 and are also divided into two major categories: (1) characteristic wastes and (2) listed wastes.

6 Chemistry and Engineering

There is often the question: why teach engineers chemistry and why teach chemists engineering? Both questions can be answered by understanding the need to establish process knowledge (reactor construction, reactor parameters) for the chemist and to establish chemical knowledge (reaction parameters, feedstock, and product properties) for engineers. This will help to establish a link between the disciplines which can then (in the context of this book) be applied to the development of pathways for a sustainable environment. Furthermore, this cross-fertilization of chemistry with the various engineering disciplines is especially useful when many technical issues cannot be dealt with successfully by a chemist of by an engineer working individually. The need is for teamwork in which professionals from both the chemical and engineering disciplines (and the related subdisciplines) work together for a better environment, sometimes referred to as a green environment which in turn is brought about by the application of chemistry and engineering to solving environmental issues. Furthermore, when applied to the development of a sustainable environment (and to add some confusion to the terminology), chemistry and engineering not only referred to as environmental chemistry and environmental engineering but also as green chemistry and green engineering. As an historical aside, environmental engineering (formerly known as sanitary engineering) originally developed as a subdiscipline of civil engineering.

The term green chemistry is often used in the context of environmental science to which can be added, in the current context, green engineering. By way of explanation, green chemistry and green engineering focus on the environmental concerns related to the use of materials, the generation of energy, and the various production cycles and can also be used to demonstrate the means by which the fundamental chemical principles, engineering principles, as well as the various chemical and engineering methodologies can be applied to the protection of the environment (Anastas and Kirchhoff, 2002). The principles of both disciplines (chemistry and engineering) are central to chemical education and to engineering education because professionals entering the environmental field need to develop the tools and skills to support the concept of global sustainability. As a result, future chemists and engineers will acquire the technical knowledge to design products and chemical processes though an increased awareness of environmental impact and understand the importance of sustainable strategies to protect the environment.

Thus, both environmental chemistry and environmental engineering course (which should be taught as cross-over inter-related courses) have the potential to add considerable enhancement to chemistry learning and to engineering leading to an improved and understanding of the chemical and engineering concepts. Incorporation of the principles of both chemistry and engineering into course material can be coupled with specific inserts that will complement the chemistry curriculum and complement the engineering curriculum and which will serve as a reminder that the practice of chemistry and the practice of engineering can lead to important developments in environmental technology (Braun et al., 2006).

The implementation of the principles of environmental chemistry for engineers and environmental engineering for chemists in any university curriculum will not only contribute to the general aims of science and engineering education but also to important elements in the development of scientific and engineering literacy and knowledge (Van Eijck and Roth, 2007). Cross-over studies will help the fledgling chemist and the fledgling engineer make the necessary connections among the disciplines of chemistry and engineering which, in turn, will contribute to the education of chemical and engineering professionals and bring about practices related to protection of the environment (Karpudewan et al., 2012).

Furthermore, cross-over studies will provide the required knowledge and awareness that lead to development of technologies that are necessary to achieve the ultimate goal of environmental protection. Teaching environmental chemistry and environmental engineering at different levels of the chemistry and engineering degree programs education has received significant attention recently (Andraos and Dicks, 2012; Eilks and Rauch, 2012; Burmeister and Eilks, 2012; Burmeister et al., 2012; Mandler et al., 2012; Karpudewan et al., 2012). The importance of this type of education, beyond the basics of chemical and engineering learning, relates to the ability to participate in the development of sustainable environmental practices (Eilks and Rauch, 2012).

Thus, an understanding of the chemical types that contribute to pollution can lead to an understanding of the chemical and physical methods (and the related process parameters) for mitigating pollution. Mitigation of such effects is not only a matter of knowing the elemental composition of the pollutant but also a matter of understanding the bulk properties as they relate to the chemical or physical composition of the material relating to the behavior of (in the context of this book) the organic chemical in the environment.