Color
Color is one of the more useful properties for identifying substances without doing any chemical or physical tests. A violet vapor, for example, is characteristic of iodine. A red brown gas could well be bromine or nitrogen dioxide NO2 a practiced eye can distinguish between the two. Just a small amount of potassium permanganate, KMnO4, in solution provides an intense purple color. A characteristic yellow brown color in water may be indicative of organically bound iron. The human eye responds...
Hazardous Wastes And The Anthrosphere
As the part of the environment where humans process substances, the anthro-sphere is the source of most hazardous wastes. These materials may come from manufacturing, transportation activities, agriculture, and any one of a number of activities in the anthrosphere. Hazardous wastes may be in any physical form and may include liquids, such as spent halogenated solvents used in degreasing parts semisolid sludges, such as those generated from the gravitation separation of oil-water-solids mixtures...
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5. What is indicated by n in a hydrocarbon name 6. Discuss the chemical reactivity of alkanes. Why are they chemically reactive or unreactive 7. Discuss the chemical reactivity of alkenes. Why are they chemically reactive or unreactive 8. What are the characteristics of aromaticity What are the chemical reactivity characteristics of aromatic compounds 9. Describe chain reactions, discussing what is meant by free radicals and photochemical processes. 10. Define, with examples, what is meant by...
Buffers
Fortunately, there are mixtures of chemicals that keep the H concentration of a solution relatively constant. Reasonable quantities of acid or base added to such solutions do not cause large changes in H concentration. Solutions that resist changes in H concentration are called buffers. To understand how a buffer works, consider a typical buffer system. A solution containing both acetic acid and sodium acetate is a good buffer. The acetic acid in the solution is present as undissociated...
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is now showing up as a low-level water pollutant in the U.S. This compound is added to gasoline as an octane booster and to decrease emissions of automotive exhaust air pollutants. A detailed study of the occurrence of MTBE in Donner Lake California showed significant levels of this pollutant, which spiked upward dramatically over a July 4 holiday.3 They were attributed largely to emissions of unburned fuel from recreational motorboats and personal watercraft having two-cycle engines that...
QUESTIONS AND PROBLEMS Smh
1. Match each organic pollutant in the left column with its expected effect in the right column, below A. CH3SH 1. Most likely to have a secondary effect in the B. CH3CH2CH2CH3 2. Most likely to have a direct effect C. S C C C H 3. Should have the least effect of these three H i i 2. Why are hydrocarbon emissions from uncontrolled automobile exhaust particularly reactive 3. Assume an accidental release of a mixture of gaseous alkanes and alkenes into an urban atmosphere early in the morning. If...
Organically Bound Metals And Metalloids
An appreciation of the strong influence of complexation and chelation on heavy metals' behavior in natural waters and wastewaters can be gained by reading Section 11.9, which deals with that subject. Methylmercury formation is also discussed in Section 11.9. Both topics involve the combination of metals and organic entities in water. The interaction of metals with organic compounds is of utmost importance in determining the role played by the metal in an aquatic system. There are two major...
LAND TREATMENT AND COMPOSTING Land Treatment
Soil can be viewed as a natural filter for wastes. Soil has physical, chemical, and biological characteristics that can enable waste detoxification, biodegradation, chemical decomposition, and physical and chemical fixation. Therefore, land treatment of wastes can be accomplished by mixing the wastes with soil under appropriate conditions. Soil is a natural medium for a number of living organisms that may have an effect upon biodegradation of hazardous wastes. Of these, the most important are...
Nature And Importance Of Chemical Analysis
Analytical chemistry is that branch of the chemical sciences employed to determine the composition of a sample of material. A qualitative analysis is performed to determine what is in a sample. The amount, concentration, composition, or percent of a substance present is determined by quantitative analysis. Sometimes both qualitative and quantitative analyses are performed as part of the same process. Analytical chemistry is important in practically all areas of human endeavor and in all spheres...
Multiplication and Division of Exponential Numbers
As with addition and subtraction, multiplication and division of exponential numbers on a calculator or computer is simply a matter of correctly pushing buttons. For example, to solve 11.39 EE-2 x 9.05 EE8 Q 3.11 EE4 4.04 EE2 same as 4.04 x 102 7.13 EE3 I 3.26 EE4 3.97 EE4 on a calculator, the sequence below is followed In multiplication and division of exponential numbers, the digital portions of the numbers are handled conventionally. For the powers of 10, in multiplication exponents are...
Reactions in Solution
One of the most important properties of solutions is their ability to allow chemical species to come into close contact so that they can react. For example, if perfectly dry crystals of calcium chloride, CaCl2, were mixed with dry crystals of sodium fluoride, NaF, a chemical reaction would not occur. However, if each is dissolved in separate solutions which are then mixed, a precipitation reaction occurs, CaCl2 aq 2NaF aq CaF2 5 2NaCl aq 7.1.1 in which calcium chloride and sodium fluoride in...
Hazardous Wastes In The Hydrosphere
Hazardous-waste substances can enter the hydrosphere as leachate from waste landfills, drainage from waste ponds, seepage from sewer lines, or runoff from soil. Deliberate release into waterways also occurs, and is a particular problem in countries with lax environmental enforcement. There are, therefore, numerous ways by which hazardous materials may enter the hydrosphere. For the most part, the hydrosphere is a dynamic, moving system, so that it provides perhaps the most important variety of...
Landfill
Landfill historically has been the most common way of disposing of solid hazardous wastes and some liquids, although it is being severely limited in many nations by new regulations and high land costs. Landfill involves disposal that is at least partially underground in excavated cells, quarries, or natural depressions. Usually fill is continued above ground to utilize space most efficiently and provide a grade for drainage of precipitation. The greatest environmental concern with landfill of...
Stratification of the Atmosphere
As shown in Figure 14.2, the atmosphere is stratified on the basis of the temperature density relationships resulting from interactions between physical and photochemical light-induced chemical phenomena processes in air. The lowest layer of the atmosphere extending from sea level to an altitude of 10-16 km is the troposphere, characterized by a generally homogeneous composition of major gases other than water and decreasing temperature with increasing altitude from the heat-radiating surface...
QUESTIONS AND PROBLEMS Ijz
1. Which of the following statements is true regarding chromium in water a chromium III is suspected of being carcinogenic, b chromium III is less likely to be found in a soluble form than chromium VI , c the toxicity of chrom-ium III in electroplating wastewaters is decreased by oxidation to chromium VI , d chromium is not an essential trace element, e chromium is known to form methylated species analogous to methylmercury compounds. 2. What do mercury and arsenic have in common in regard to...
Biorefractory Organic Pollutants
Millions of tons of organic compounds are manufactured globally each year. Significant quantities of several thousand such compounds appear as water pollutants. Most of these compounds, particularly the less biodegradable ones, are substances to which living organisms have not been exposed until recent years. Frequently, their effects upon organisms are not known, particularly for long-term exposures at very low levels. The potential of synthetic organics for causing genetic damage, cancer, or...
Water Sample Preservation
It is not possible to completely protect a water sample from changes in composition. However, various additives and treatment techniques can be employed to minimize sample deterioration. These methods are summarized in Table 26.1. The most general method of sample preservation is refrigeration to 4 C. Freezing normally should be avoided because of physical changes formation of precipitates and loss of gas that can adversely affect sample composition. Acidification is commonly applied to metal...
Industrial Wastewater Treatment
Before treatment, industrial wastewater should be characterized fully and the biodegradability of wastewater constituents determined. The options available for the treatment of wastewater are summarized briefly in this section and discussed in greater detail in later sections. One of two major ways of removing organic wastes is biological treatment by an activated sludge or related process see Section 13.4 and Figure 13.3 . It may be necessary to acclimate microorganisms to the degradation of...
Heavy Metals 1
Heavy metals are toxic in their chemically combined forms and some, notably mercury, are toxic in the elemental form. The toxic properties of some of the most hazardous heavy metals and metalloids are discussed here. Although not truly a heavy metal, beryllium atomic mass 9.01 is one of the more hazardous toxic elements. Its most serious toxic effect is berylliosis, a condition manifested by lung fibrosis and pneumonitis, which may develop after a latency Table 23. 2 Materials Listed by ATS...
Solidification
Solidification may involve chemical reaction of the waste with the solidification agent, mechanical isolation in a protective binding matrix, or a combination of chemical and physical processes. It can be accomplished by evaporation of water from aqueous wastes or sludges, sorption onto solid material, reaction with cement, reaction with silicates, encapsulation, or embedding in polymers or thermoplastic materials. In many solidification processes, such as reaction with Portland cement, water...
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Section 4.6. Some other Aspects of Covalent Bonding 18. What are multiple bonds Which three elements are most likely to form multiple bonds 19. What can be said about the nature of covalent bonds between a 2 atoms with almost identical electronegativity values and b 2 atoms with substantially different electronegativity values 20. What symbols are used to show bond polarity 21. What is the ultimate in polar bonds 22. A molecule of NH3 will combine with one of BF3. Describe the kind of bond...
Ions and Radicals in the Atmosphere
One of the characteristics of the upper atmosphere that is difficult to duplicate under laboratory conditions is the presence of significant levels of electrons and positive ions. Because of the rarefied conditions, these ions may exist in the upper atmosphere for long periods before recombining to form neutral species. At altitudes of approximately 50 km and up, ions are so prevalent that the region is called the ionosphere. The presence of the ionosphere has been known since about 1901, when...
Sulfur Dioxide Sources And The Sulfur Cycle
Figure 15.8 shows the main aspects of the global sulfur cycle. This cycle involves primarily H2S, CH3 2S, SO2, SO3, and sulfates. There are many uncertainties regarding the sources, reactions, and fates of these atmospheric sulfur species. Approximately 100 million metric tons of sulfur per year enter the global atmosphere through anthropogenic activities, primarily as SO2 from the combustion of coal and residual fuel oil. The greatest uncertainties in the cycle have to do with nonanthropogenic...
Supplementary References 1
Allen, Herbert E., A. Wayne Garrison, and George W. Luther, Metals in Surface Waters, CRC Press Lewis Publishers, Boca Raton, FL, 1998. Barbash, Jack E., Elizabeth A. Resek, and Robert J. Gilliom, Eds., Pesticides in Ground Water Distribution, Trends, and Governing Factors, Vol. 2, Ann Arbor Dolan, Edward F., Our Poisoned Waters, Cobblehill Books, New York, NY, 1997. Eckenfelder, W. Wesley, Industrial Water Pollution Control, 3rd ed., McGraw- Gustafson, David, Pesticides in Drinking Water, Van...
Alkene and Alkyne Hydrocarbons
Ethylene, a widely used colorless gas with a somewhat sweet odor, acts as a simple asphyxiant and anesthetic to animals and is phytotoxic toxic to plants . The toxicological properties of propylene H2C CHCH3 are very similar to those of ethylene. Colorless, odorless, gaseous 1,3-butadiene H2C CHCH CH2 is an irritant to eyes and respiratory system mucous membranes at higher levels it can cause unconsciousness and even death. Acetylene, H-C C-H, is a colorless gas with a garlic odor that acts as...
Effects of Urbanization on Microclimate
A particularly marked effect on microclimate is that induced by urbanization. In a rural setting, vegetation and bodies of water have a moderating effect, absorbing modest amounts of solar energy and releasing it slowly. The stone, concrete, and asphalt pavement of cities have an opposite effect, strongly absorbing solar energy, and re-radiating heat back to the urban microclimate. Rainfall is not allowed to accumulate in ponds, but is drained away as rapidly and efficiently as possible. Human...
Lubricating Oil
Lubricating oils are used in vast quantities and are prime candidates for recycling. The simplest means of recycling lubricating oil is to burn it, and large volumes of oil are burned for fuel. This is a very low level of recycling and will not be addressed further here. For many years, the main process for reclaiming waste lubricating oil used treatment with sulfuric acid followed by clay. This process generated large quantities of acid sludge and spent clay contaminated with oil. These...
SUPPLEMENTARY REFERENCES Wfh
Christian, Gary D., Analytical Chemistry, 5th ed., John Wiley amp Sons, New York, 1994. Day, R. A. and Arthur L. Underwood, Quantitative Analysis, 6th ed., Prentice Hall, Upper Saddle River, NJ, 1991. Ewing, Galen Wood, Ed., Analytical Instrumentation Handbook, 2nd ed, Marcel Dekker, New York, 1997. Gill, Robin, Ed., Modern Analytical Geochemistry An Introduction to Quantitative Chemical Analysis Techniques for Earth, Environmental and Materials Scientists, Addison Wesley, Harlow, U.K., 1997....
Mercury
Because of its toxicity, mobilization as methylated forms by anaerobic bacteria, and other pollution factors, mercury generates a great deal of concern as a heavy-metal pollutant. Mercury is found as a trace component of many minerals, with continental rocks containing an average of around 80 parts per billion, or slightly less, of this element. Cinnabar, red mercuric sulfide, is the chief commercial mercury ore. Fossil fuel coal and lignite contain mercury, often at levels of 100 parts per...
DDT and Organochlorine Insecticides
Chlorinated hydrocarbon or organochlorine insecticides are hydrocarbon compounds in which various numbers of hydrogen atoms have been replaced by Cl atoms. The structural formulas of several chlorinated hydrocarbon insecticides are shown in Figure 12.6. It can be seen that the structural formulas of many of these insecticides are very similar dieldrin and endrin are stereoisomers. The most commonly used insecticides in the 1960s, these compounds have been largely phased out of general use...
Sample Digestion
To analyze a solid waste sample by flame atomic absorption spectroscopy, graphite furnace absorption spectroscopy, inductively coupled argon plasma spectroscopy, or inductively coupled argon plasma mass spectrometry, the sample must first be digested to get the analyte metals in solution. Digestion dissolves only those fractions of metals that can be put into solution under relatively extreme conditions and therefore enables measurement of available metals. It should be noted that sample...
Macronutrients In Soil
One of the most important functions of soil in supporting plant growth is to provide essential plant nutrients macronutrients and micronutrients. Macronu-trients are those elements that occur in substantial levels in plant materials or in fluids in the plant. Micronutrients Section 18.6 are elements that are essential only at very low levels and generally are required for the functioning of essential enzymes. The elements generally recognized as essential macronutrients for plants are carbon,...
Toxicity Characteristic Leaching Procedure
For regulatory and remediation purposes, a standard test is needed to measure the likelihood of toxic substances getting into the environment and causing harm to organisms. The U.S. Environmental Protection Agency specifies a test called the Toxicity Characteristic Leaching Procedure TCLP designed to determine the toxicity hazard of wastes.6 The test was designed to estimate the availability to organisms of both inorganic and organic species in hazardous materials present as liquids, solids, or...
Hazardous Wastes In The Atmosphere
Hazardous-waste chemicals can enter the atmosphere by evaporation from hazardous-waste sites, by wind erosion, or by direct release. Hazardous-waste chemicals usually are not evolved in large enough quantities to produce secondary air pollutants. Secondary air pollutants are formed by chemical processes in the atmosphere. Examples are sulfuric acid formed from emissions of sulfur oxides and oxidizing photochemical smog formed under sunny conditions from nitrogen oxides and hydrocarbons....
Organonitrogen Compounds
Organonitrogen compounds constitute a large group of compounds with diverse toxicities. Examples of several of the kinds of organonitrogen compounds discussed here are given in Figure 23.20. The lower amines, such as the methylamines, are rapidly and easily taken into the body by all common exposure routes. They are basic and react with water in tissue, R3N H2O R3NH OH- 23.13.1 raising the pH of the tissue to harmful levels, acting as corrosive poisons especially to sensitive eye tissue , and...
Oxygen Oxidants And Reductants
Oxygen is a vitally important species in water see Chapter 11 . In water, oxygen is consumed rapidly by the oxidation of organic matter, CH2O CH2O O2 MicroorganismV CO2 H2O 12.9.1 Unless the water is reaerated efficiently, as by turbulent flow in a shallow stream, it rapidly loses oxygen and will not support higher forms of aquatic life. In addition to the microorganism-mediated oxidation of organic matter, oxygen in water may be consumed by the biooxidation of nitrogenous material, NH4 2O2 2H...
Chemical And Photochemical Reactions In The Atmosphere
Figure 14.8 represents some of the major atmospheric chemical processes, which are discussed under the topic of atmospheric chemistry. The study of atmospheric chemical reactions is difficult. One of the primary obstacles encountered in studying atmospheric chemistry is that the chemist generally must deal with incredibly low concentrations, so that the detection and analysis of reaction products is quite difficult. Simulating high-altitude conditions in the laboratory can be extremely hard...
Organophosphate Insecticides
Organophosphate insecticides are insecticidal organic compounds that contain phosphorus, some of which are organic esters of orthophosphoric acid, such as paraoxon More commonly, insecticidal phosphorus compounds are phosphorothionate compounds, such as parathion or chlorpyrifos, which have an S group rather than an O group bonded to P. The toxicities of organophosphate insecticides vary a great deal. For example, as little as 120 mg of parathion has been known to kill an adult human, and a...
Calcination of Limestone
To illustrate some of the quantitative information that may be obtained from chemical equations, consider the calcination of limestone to make quicklime for water treatment Limestone, calcium Quicklime, calcium carbonate oxide Limestone, calcium Quicklime, calcium carbonate oxide Figure 5.4 Heating calcium carbonate to a high temperature results in the production of quicklime, CaO, and the evolution of carbon dioxide. The reaction is a decomposition reaction and the process is called...
Classical Methods Of Water Analysis
The most common classical methods for water analysis are titrations. Some of the titration procedures used are discussed in this section. The principles of titration analysis are discussed in Chapter 25, Section 25.6. Acidity see Chapter 11, Section 11.6 is determined simply by titrating hydrogen ion with base. Titration to the methyl orange endpoint pH 4.5 yields the free acidity due to strong acids HCl, H2SO4 . Carbon dioxide does not, of course, appear in this category. Titration to the...
Toxic Organometallic Compounds
Organometallic compounds are those in which metals are bound to carbon atoms in hydrocarbon groups or, in the case of carbonyls, to CO molecules. Widely used for a number of applications, organometallic compounds have a variety of toxic effects. They often behave in the body in ways totally unlike the inorganic forms of the metals that they contain, due in large part to the fact that, compared with inorganic forms, organometallic compounds have an organic nature, higher lipid solubility, and...
QUESTIONS AND PROBLEMS Jxs
1. During municipal water treatment, air is often mixed intimately with the water, that is, it is aerated. What kinds of undesirable contaminants would this procedure remove from water 2. What is the purpose of the return sludge step in the activated sludge process 3. What are the two processes by which the activated sludge process removes soluble carbonaceous material from sewage 4. Why might hard water be desirable as a medium if phosphorus is to be removed by an activated sludge plant...
Hydroxyl and Hydroperoxyl Radicals in the Atmosphere
The hydroxyl radical, HO is the single most important reactive intermediate species in atmospheric chemical processes. It is formed by several mechanisms. At higher altitudes, it is produced by photolysis of water In the presence of organic matter, hydroxyl radical is produced in abundant quantities as an intermediate in the formation of photochemical smog see Chapter 16 . To a certain extent in the atmosphere, and for laboratory experimentation, HO is made by the photolysis of nitrous acid...
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Figure 16.7 Organonitrogen compounds that may be encountered as air pollutants. Amines consist of compounds in which one or more of the hydrogen atoms in NH3 has been replaced by a hydrocarbon moiety. Lower-molecular-mass amines are volatile. These are prominent among the compounds giving rotten fish their characteristic odor an obvious reason that air contamination by amines is undesirable. A number of amines are widely used industrial chemicals and solvents, so industrial sources have the...
Water the Greenest Solvent
Although it does not truly dissolve hydrophobic organic substances, but may hold them in suspension as finely divided colloidal matter, water can often be used in place of organic solvents as a medium for organic reactions and for other applications. In addition to its not dissolving organic substances, water suffers from the disadvantage of reacting strongly with some reagents, such as AlCl3 used in Friedel-Crafts reactions, strongly reducing LiAlH4, and metallic sodium used in some...
Gasohol
A major option for converting photosynthetically produced biochemical energy to forms suitable for internal combustion engines is the production of either methanol or ethanol. Either can be used by itself as fuel in a suitably designed internal combustion engine. More commonly, these alcohols are blended in proportions of up to 20 with gasoline to give gasohol, a fuel that can be used in existing internal combustion engines with little or no adjustment. Gasohol boosts octane rating and reduces...
QUESTIONS AND PROBLEMS Mtm
1. How are conjugating agents and Phase II reactions involved with some toxicants 2. What is the toxicological importance of proteins, particularly as related to protein structure 3. What is the toxicological importance of lipids How are lipids related to hydrophobic pollutants and toxicants 4. What are Phase I reactions What enzyme system carries them out Where is this enzyme system located in the cell 5. Name and describe the science that deals with the chemical nature and reactions of toxic...
Nitrogen Removal
Next to phosphorus, nitrogen is the algal nutrient most commonly removed as part of advanced wastewater treatment. The techniques most often used for nitrogen removal are summarized in Table 13.2. Nitrogen in municipal wastewater generally is present as organic nitrogen or ammonia. Ammonia is the primary nitrogen product produced by most biological waste treatment processes. This is because it is expensive to aerate sewage sufficiently to oxidize the ammonia to nitrate through the action of...
Units Of Volume
The basic metric unit of volume is the liter, which is defined in terms of metric units of length. As shown in Figure 1.9, a liter is the volume of a decimeter cubed, that is, 1 L 1 dm3 a dm is 0.1 meter, about 4 inches . A milliliter mL is the same volume as a centimeter cubed cm3 or cc , and a liter is 1000 cm3. A kiloliter, usually designated as a cubic meter m3 , is a common unit of measurement for the volume of air. For example, standards for human exposure to toxic substances in the...
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Figure 9.4 Structural formulas of four hydrocarbons, each containing 8 carbon atoms, that illustrate the structural diversity possible with organic compounds. Numbers used to denote locations of atoms for purposes of naming are shown on two of the compounds. Formulas of organic compounds present information at several different levels of sophistication. Molecular formulas, such as that of octane C8H18 , give the number of each kind of atom in a molecule of a compound. As shown in Figure 9.3,...