McKay, Donald. "Front matter" Multimedia Environmental Models ...

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of complex and variable structure that are naturally present in soils, water, and sediments. They are the remnants of living organic materials, such as wood, that has been subjected to prolonged microbial conversion. These acids are sparingly soluble in water, but the solubility can be increased at high pH. The esters or “salts” or organic acids and alcohols tend to be relatively innocuous and short-lived in most cases. A notable exception is the phthalate esters, which are very stable oily substances and are invaluable additives (plasticizers) for plastics, rendering them more flexible. Notable among the phthalate esters is diethylhexylphthalate (DEHP), the ester with two molecules of 2 ethylhexanol. The other esters of interest are the glycerides—for example, glyceryl trioleate, the ester of glycerine and oleic acid. This chemical has similar properties to fat and has been suggested as a convenient surrogate for measuring fat to water partitioning. The “dioxins” and “furans” are two series of organic compounds that have become environmentally notorious. The chlorinated dibenzo-p-dioxins were never produced intentionally but are formed under combustion conditions when chlorine is present. They form a series of very toxic chemicals, the most celebrated of which is 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). TCDD is possibly the most toxic chemical to mammals. A dose of 2 mg of TCDD per kg of body weight is sufficient to kill small rodents. A related series of chemicals is the dibenzofurans, which are similar in properties to the dioxins. It appears that molecules that are long and flat, with chlorine atoms strategically located at the ends, are particularly toxic. Examples are the chloronaphthalenes, DDT, the PCBs, and chlorinated dibenzo-p-dioxins and dibenzofurans. Other oxygenated compounds of interest include carbohydrates, cellulose, and lignins, which occur naturally. 3.3.2.4 Nitrogen Compounds Nitrogen compounds of environmental interest include amines, amides, pyridines, quinolines, and amino acids, and various nitro compounds including nitro polycyclicaromatics and nitroso compounds. Many of these compounds occur naturally, are quite toxic, and are difficult to analyze. 3.3.2.5 Sulfur Compounds Sulfur compounds, including thiols, thiophenes, and mercaptans, are well known because of their strong odor. One of the most prevalent classes of synthetic organic chemicals is the alkyl benzene sulfonates, which are widely used in detergents. 3.3.2.6 Phosphorus Compounds Phosphorus compounds play a key role in energy transfer in organisms. Organophosphate compounds have been developed as pesticides (e.g., chloropyrifos), which have the very desirable properties of high biological activity but relatively short environmental persistence. They have therefore largely replaced organo-chlorine compounds in agriculture. ©2001 CRC Press LLC
3.3.2.7 Arsenic Compounds Arsenic, which behaves somewhat similarly to phosphorus, is inadvertently liberated in mineral processing and has a long and celebrated history as a poison. It usually exists in anionic and organic forms. 3.3.2.8 Metals Most metals are essential for human life in small quantities but can be toxic if administered in excessive dosages. The metals of primary toxicological interest here are those that form organo-metallic molecules. Notable is mercury, which can exist as the element in various ionic and organometallic forms. Other metals such as lead and tin behave similarly. A formidable literature exists on the behavior, fate, and effects of the “heavy” metals such as lead, copper, and chromium. These metals often have a complex environmental chemistry and toxicology that vary considerably, depending on their ionic state as influenced by acidity and redox status. 3.3.2.9 Pharmaceuticals and Personal Care Products Considerable quantities of drugs are used by humans and for veterinary purposes on livestock. Antibiotics and steroids are examples. These substances are excreted and may pass through sewage treatment plants or enter soils or groundwater following agricultural use. There is a growing concern that these substances may have adverse effects or may cause an increase in antibiotic resistance in bacteria. Among personal care products of concern are detergents, fabric softeners, fragrances, and certain solvents. They may evaporate or be discharged with sewage, which may or may not be adequately treated. 3.3.2.10 Other Chemicals Several other chemicals are of environmental concern including ozone, radon, chlorine, organic and inorganic sulfides and cyanides, as well as the indeterminate broad class of “conventional” pollutants or indicators of pollution such as biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Finally, certain mineral substances such as asbestos are of concern, more because of their physical structure than their chemical composition. 3.3.2.11 The Future It would be unwise to assume that current lists of priority chemicals are complete and will remain static. It may be that the chemicals on the lists reflect our present ability to detect and analyze them rather than their real environmental significance. The prevalence of organo-chlorine chemicals on lists is in part the result of the sensitive electron capture detector. As new analytical methods emerge, new chemicals will presumably be found, and priorities will change. Happy hunting grounds for environmental chemists include combustion gases, dyes, mine tailings, effluents ©2001 CRC Press LLC
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McKay, Donald. "Front matter" Multi
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Multimedia Environmental Models The
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hensive, and reliable, and they hav
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Chapter 1 Introduction Chapter 2 So
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McKay, Donald. "Introduction" Multi
Page 11 and 12: It is now evident that our task is
Page 13 and 14: McKay, Donald. "Some Basic Concepts
Page 15 and 16: give the derived units directly wit
Page 17 and 18: Energy (joule, J) The joule, which
Page 19 and 20: particles (aerosols), or biota in w
Page 21 and 22: Worked Example 2.1 A three-phase sy
Page 23 and 24: (i) What is the concentration (C) i
Page 25 and 26: Answer ©2001 CRC Press LLC 5.1 kg,
Page 27 and 28: or or When t is zero, C is zero, th
Page 29 and 30: What is the absolute minimum piscic
Page 31 and 32: ©2001 CRC Press LLC C 1 = C O/(1 +
Page 33 and 34: containing nonequilibrium quantitie
Page 35 and 36: 1. Fallout of chemical from air to
Page 37 and 38: validated using real environments.
Page 39 and 40: ©2001 CRC Press LLC CHAPTER 3 Envi
Page 41 and 42: of other, somewhat similar or homol
Page 43 and 44: Table 3.2 List of Chemicals Commonl
Page 45 and 46: elatively high concentrations. This
Page 47 and 48: exists between toxicologists and ch
Page 49 and 50: determine priority. This is a subje
Page 51 and 52: Another important classification of
Page 53 and 54: Figure 3.1 (continued) ©2001 CRC P
Page 55 and 56: Table 3.5 (continued) dichlorometha
Page 57 and 58: Table 3.5 (continued) total PCB 326
Page 59 and 60: Figure 3.2 Plot of log K AW vs. log
Page 61: chlorofluoro compounds are very sta
Page 65 and 66: McKay, Donald. "The Nature of Envir
Page 67 and 68: Figure 4.1 Evaluative environments.
Page 69 and 70: are subject to two important deposi
Page 71 and 72: metals and organic chemicals from w
Page 73 and 74: carbon figure for deeper sediments
Page 75 and 76: flows. The quality of this groundwa
Page 77 and 78: Table 4.2 Evaluative Environments A
Page 79 and 80: McKay, Donald. "Phase Equilibrium"
Page 81 and 82: Figure 5.1 Some principles and conc
Page 83 and 84: likely using an equilibrium criteri
Page 85 and 86: Another useful quantity is the rati
Page 87 and 88: experimentally, but not directly, u
Page 89 and 90: ©2001 CRC Press LLC 5.3 PROPERTIES
Page 91 and 92: 1.0. This, then, is the fugacity or
Page 93 and 94: where ©2001 CRC Press LLC pH is -l
Page 95 and 96: In terms of solubilities, S iA and
Page 97 and 98: The temperature coefficient is the
Page 99 and 100: (1982), Baum (1997) and Leo (2000).
Page 101 and 102: Although it may appear environmenta
Page 103 and 104: Figure 5.4 Illustration of quantita
Page 105 and 106: 5.5 ENVIRONMENTAL PARTITION COEFFIC
Page 107 and 108: C S = K PC W benzene = 1.1 ¥ 0.001
Page 109 and 110: Mackay (1986), in an attempt to sim
Page 111 and 112: Compartment Definition of Fugacity
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high concentration in the fish, but
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heat capacity of 0.38 J/g°C requir
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Therefore, ©2001 CRC Press LLC f =
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©2001 CRC Press LLC Z T = S(V i/V
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©2001 CRC Press LLC air Z = P S /R
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Table 5.1 Table 5.1 Summary of Defi
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Figure 5.7 Fugacity form 1 for dedu
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Calculate the following physical-ch
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©2001 CRC Press LLC CHAPTER 6 Adve
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that all water will spend 100 days
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This enables us to conceive of, and
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©2001 CRC Press LLC f = 15/0.5 = 3
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D AS dominates. A residence time of
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and Therefore, ©2001 CRC Press LLC
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eaction situation in which there is
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The rate constants in each case are
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©2001 CRC Press LLC 1/t O = SD Ai/
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e achieved in 10 days. Detractors o
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sulfate to sulfide or by dechlorina
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to Zepp and Cline (1977) for the or
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©2001 CRC Press LLC 6.7 LEVEL II C
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Figure 6.3 Fugacity Level II calcul
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McKay, Donald. "Intermedia Transpor
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Figure 7.1 Illustration of nonequil
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5. Diffusion within soils, and from
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sionally, the term flux rate is use
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©2001 CRC Press LLC N = ABDC/ Dy m
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no currents or eddies. In practice,
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diffusivity, and some unknown layer
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where ©2001 CRC Press LLC X = y/ U
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fraction of the total volume that i
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Figure 7.6 Mass transfer at the int
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partition coefficient. The signific
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and the series retains a similar ra
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ments of resuspension rates are par
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Figure 7.8 Movement of air phase (k
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ates can thus be used to estimate m
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Figure 7.9 Combination of D values
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Figure 7.10 Four-compartment Level
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Table 7.2 Order of Magnitude Values
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Unlike the Level II calculation, it
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Figure 7.12 Sample Level III output
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McKay, Donald. "Applications of Fug
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applications. Citations are given t
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Another approach is to employ Monte
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LEVEL1B A six-compartment Level I p
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Figure 8.1 Air-water exchange proce
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The total rates of transfer are thu
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Figure 8.2 Chemical transport and t
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mean. For chemical between depths o
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8.5.2 Process Description The water
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learn the benefits of using fugacit
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where Figure 8.5 QWASI model: stead
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are similar to those described by M
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C F ª Z Ff W ª 1.608 mol/m 3 ª 4
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y Mackay et al. (1983), and an appl
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accordingly, but the final solution
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Figure 8.10 Fish bioaccumulation pr
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The nature of the processes control
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iomagnification is more significant
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An alternative and more elegant met
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8.11.2 Model of a Chemical Evaporat
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Paterson et al. (1991), and Hung an
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8.14.1 Introduction ©2001 CRC Pres
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mated again in mg/day. Food, the ot
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models. Most interest is in LRT in
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available from the University of To
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McKay, Donald. "Appendix" Multimedi
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©2001 CRC Press LLC
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