chemistry

CHAPTER 2

CHLORINATED SOLVENT CHEMISTRY: STRUCTURES,NOMENCLATURE AND PROPERTIES

David M. Cwiertny1 and Michelle M. Scherer2

1University of California at Riverside, Riverside, CA 92521; 2The University of Iowa, IowaCity, IA 52242

2.1 INTRODUCTION

This chapter summarizes the principles of chlorinated solvent remediation, provides over-views of the biotic and abiotic reactions that can transform and detoxify these compounds, anddiscusses the remediation challenges posed by the properties and behavior of these compoundsin the subsurface environment.

2.2 STRUCTURE AND NOMENCLATURE

Chlorinated solvents are organic compounds generally constructed of a simple hydrocar-bon chain (typically one to three carbon atoms in length) to which at least one chlorine atom iscovalently bonded. For the current discussion, chlorinated solvents will be further divided intothree categories based upon common structural characteristics: chlorinated methanes, chlori-nated ethanes and chlorinated ethenes. Examples from each solvent class are shown inFigure 2.1. Additional information pertaining to the nomenclature of these chemical speciesis provided in Table 2.1.

Chlorinated methanes represent the most structurally simple solvent class and consist ofa single carbon center (known as a methyl carbon) to which as many as four chlorine atomsare covalently bonded. From the perspective of groundwater contamination, perhaps themost well known chlorinated methane is carbon tetrachloride (CT). Also known by itsInternational Union of Pure and Applied Chemistry (IUPAC) name of tetrachloromethane,CT consists of a fully chlorinated methyl carbon. By IUPAC conventions, the modifier oftetra serves as an indicator of the number of chlorine atoms bound to the carbon center. Forchlorinated methanes other than CT, hydrogen atoms usually make up the remainder of thesubstituents necessary to satisfy the methyl carbons bonding requirements. Named in asimilar fashion by IUPAC, the chlorinated methanes with a lower degree of halogenation aretrichloromethane (commonly referred to as chloroform [CF]), dichloromethane (DCM, morecommonly called methylene chloride [MC]) and chloromethane (CM, also referred to asmethyl chloride).

Chlorinated ethanes consist of two carbon centers joined by a single covalent bond.Common groundwater pollutants from this class include 1,1,1-trichloroethane (1,1,1-TCA) and1,2-dichloroethane. In regards to the nomenclature associated with chlorinated ethanes, asimilar convention to that used for chlorinated methanes is employed in which the prefixattached to chloroethane indicates the total number of chlorine atoms on the solventmolecule. Common acronyms for this class follow the pattern in which the first letter (or seriesof letters) refers to the number of total halogen substituents (e.g., T for trichloro- or Te for

H.F. Stroo and C.H. Ward (eds.), In Situ Remediation of Chlorinated Solvent Plumes,doi: 10.1007/978-1-4419-1401-9_2,# Springer Science+Business Media, LLC 2010

29

tetrachloro-), the second letter refers to the halogen identity (e.g., C for chlorine) and the lastletter, in all cases A, refers to ethane.

In addition, the numbers preceding the name or abbreviation indicate the location of thechlorine substituents on the two possible carbon centers. For example, 1,1,2,2-tetrachloroethane(1,1,2,2-TeCA) possesses two chlorine atoms on each of its carbon centers, whereas the threechlorine atoms of 1,1,1-TCA are all located on the same carbon. In certain instances, there canbe more than one way in which the same number of chlorine atoms distribute themselves on thecarbon centers, as is the case for 1,1,2-TCA and 1,1,1-TCA. These compounds, which share thesame chemical formula (C2H3Cl3) yet differ in the sequence in which their atoms are connected,are referred to as structural isomers (Vollhardt and Schore, 1994).

Chlorinated ethenes (sometimes referred to as chlorinated ethylenes) also possess twocarbon centers, but unlike chlorinated ethanes, these carbon atoms are joined by a carbon-carbon double bond known as a p-bond (pi-bond) system. Another important differencebetween chlorinated ethanes and chlorinated ethenes is the maximum number of atomsbound to the carbon centers in each case. The double-bonded carbon centers in chlorinatedethenes can accommodate at most two halogen (or hydrogen) substituents, whereas the single-bonded ethanes can accommodate three halogen (or hydrogen) substituents.

Examples of chlorinated ethenes that are important groundwater pollutants include tetra-chloroethene, commonly referred to as perchloroethene (PCE), and trichloroethene (TCE).Another chlorinated ethene of note is the monochlorinated species that is most commonlyreferred to as vinyl chloride (VC). The nomenclature associated with the chlorinated ethenesfollows a similar convention to that used with the chlorinated methanes and ethanes

H

Cl

ClH

CCl

Cl

Cl

ClC

Cl

H H

H

CC

Cl

HH

HCl

Cl

C C

ClH

Cl Cl

C C

Cl

Cl Cl

C C

Cl

Cl

H

HCl

ClC C

Cl

dichloromethane(DCM)

carbon tetrachloride(CT)

1,1,1 - trichloroethane(1,1,1-TCA)

vinyl chloride(VC)

1,1,2,2 - tetrachloroethane(1,1,2,2-TeCA)

trichloroethene(TCE)

perchloroethene(PCE)

Figure 2.1. Chemical structures of some common chlorinated solvents.

30 D.M. Cwiertny and M.M. Scherer

(e.g., tetrachloroethene contains four chlorine substituents). The same is true for the acronymscommonly applied to this solvent class, only this time the last letter in all cases is E, whichrepresents ethenes. The lone exception to this convention for acronyms is vinyl chloride,which is typically abbreviated as VC.

Additional nomenclature is necessary in order to distinguish the possible isomers ofdichloroethene. As with 1,1,1-TCA and 1,1,2-TCA, dichloroethene (DCE) can exist as either oftwo structural isomers (1,1-DCE and 1,2-DCE). In addition, the p-bond system in chlorinatedethenes differs from the single carbon-carbon bond in chlorinated ethanes because it does notallow the halogen substituents to rotate freely in the plane perpendicular to the direction of thep-bond. Consequently, there are multiple spatial orientations for the two chloride substituentsin 1,2-dichloroethene (Figure 2.2). One possibility is for the chlorine atoms to arrange them-selves on the same side of the carbon-carbon double bond in a configuration known as cis.Alternatively, the chlorine atoms can be located on the opposite side of the p-bond system in aconfiguration known as trans. These two dichloroethenes, which are structurally identical butdiffer in the spatial arrangement of their chlorine substituents, are called conformationalisomers (or simply conformers) (Vollhardt and Schore, 1994).

Table 2.1. Nomenclature for Selected Chlorinated Solvents

IUPAC Name Common Name Abbreviation/Acronym Molecular Formula

Chlorinated Methanes

tetrachloromethane carbon tetrachloride CT CCl4

trichloromethane chloroform CF CHCl3

dichloromethane methylene chloride DCM CH2Cl2

chloromethane methyl chloride CM CH3Cl

Chlorinated Ethanes

hexachloroethane perchloroethane HCA C2Cl6

pentachloroethane ---- PCA C2HCl5

1,1,1,2-tetrachloroethane ---- 1,1,1,2-TeCA C2H2Cl4

1,1,2,2-tetrachloroethane ---- 1,1,2,2-TeCA C2H2Cl4

1,1,2-trichloroethane ---- 1,1,2-TCA C2H3Cl3

1,1,1-trichloroethane methyl chloroform 1,1,1-TCA C2H3Cl3

1,2-dichloroethane ---- 1,2-DCA C2H4Cl2

1,1-dichloroethane ---- 1,1-DCA C2H4Cl2

chloroethane ---- CA C2H5Cl

Chlorinated Ethenes

tetrachloroethene perchloroethene PCE C2Cl4

trichloroethene ---- TCE C2HCl3

cis-1,2-dichloroethene cis-dichloroethene cis-DCE C2H2Cl2

trans-1,2-dichloroethene trans-dichloroethene trans-DCE C2H2Cl2

1,1-dichloroethene vinylidene chloride 1,1-DCE C2H2Cl2

chloroethene vinyl chloride VC C2H3Cl

Chlorinated Solvent Chemistry: Structures, Nomenclature and Properties 31

Chlorinated methanes, ethanes and ethenes clearly do not encompass all types of chlori-nated solvents that may be encountered at hazardous waste sites. For instance, chlorinatedpropanes, which possess three carbon atoms joined by single bonds, can represent importantgroundwater pollutants. Some examples of chlorinated propanes include 1,2-dichloropropane,which is regulated in drinking water by the U.S. Environmental Protection Agency (USEPA)(2003). Another example is 1,2,3-trichloropropane, which has been detected at more than 20National Priorities List sites identified by the USEPA (ATSDR, 1992). Although such speciesare not the focus of subsequent portions of this chapter, the physical and chemical principlesdeveloped for chlorinated methanes, ethanes and ethenes can easily be extended to includethese additional chlorinated solvents.

Although this chapter is devoted to treatment strategies for chlorinated solvents, solventswith other halogen substituents (such as bromine or fluorine) are also frequently encountered incontaminated groundwater. A common example is 1,2-dibromoethane (also known as ethylenedibromide [EDB]), which was used as an additive in leaded gasoline (Baird and Cann, 2005).Methanes, ethanes and ethenes with mixed halogen substituents can represent importantenvironmental pollutants as well, as is the case for common disinfection byproducts bromodi-chloromethane (CHBrCl2) and dibromochloromethane (CHBr2Cl). When necessary, key differ-ences in the behavior and environmental fate of halogenated solvents with chlorine, bromineand fluorine substituents will be noted.

2.3 PROPERTIES

The behavior of chlorinated solvents in the subsurface is controlled to a large extent by theirphysical and chemical properties. The properties considered most relevant to chlorinatedsolvent fate and transport in the subsurface are summarized in Table 2.2. In order to maintainsome consistency among the values presented, the majority of the values were obtained fromMackay et al. (1993), one of the very few sources that contain data for all of the chlorinatedmethanes, ethanes and ethenes. In general, there is reasonable agreement between these valuesand several other summary tables available (e.g., Pankow and Cherry, 1996; Fetter, 1999;Schwarzenbach et al., 2003; Chapter 1 of this volume). Table 2.2 is provided for purposes ofdiscussion with regards to relevant trends in behavior and properties and is not intended as a setof values selected from a critical review of the literature. For a review of the primary literature,Pankow and Cherry (1996) is recommended because it provides a detailed review of thechlorinated solvent properties discussed herein as well as an excellent discussion of the historyof production and industrial uses of chlorinated solvents.

The following discussion of chemical and physical properties is organized around the majorprocesses that impact the fate and transport of chlorinated solvents in the subsurface, startingwith the process by which pure phase chlorinated solvents dissolve into groundwater, followedby their partitioning between the three phases present in the subsurface: aquifer solids, waterand air. An overview linking these partitioning processes to the relevant chlorinated solventproperties is provided in Figure 2.3. The discussion concludes with an introduction to trans-formation reactions, which are discussed in greater detail in Chapters 3 and 4.

H

Cl Cl

H

CC

H

Cl H

Cl

CC

cis-DCE trans-DCEFigure 2.2. Conformational isomers of 1,2-dichloroethene.


2.3.1 Dissolution

At room temperature (25 degrees Celsius [C]), most chlorinated solvents are colorlessliquids with densities (r) greater than that of water (rsolvent > 1 gram per liter [g/L]).

Table 2.2. Summary of Some Physical and Chemical Properties of Chlorinated Organic Solvents at25DegreesCelsius (C).Unlessotherwisenoted, all valueshavebeen taken fromMackayet al. (1993).

Species

FormulaWeight(g/mol)

CarbonOxidationStatea

Density(r) (g/mL)

Solubility (S)(mg/L)

VaporPressure(po) (torr)

HenrysLaw

Constant(KH) ( 10-3atmm3/mol)

Log(Kow)

Log(Koc)

bMCLc

(mg/L)

Chlorinated Methanes

CT 153.8 +IV 1.59 800 153.8 28.9 2.64 1.9 0.005

CF 119.4 +III 1.49 8,200 196.8 3.8 1.97 1.52 0.10d

DCM 84.9 +II 1.33 13,200 415 1.7 1.25 ---- 0.005

CM 50.5 +I 0.92 5,235 4,275 9.6 0.91 ---- NRe

Chlorinated Ethanes

HCA 236.7 +III 2.09 50 0.38f ---- 3.93 ---- NR

PCA 202.3 +II 1.68 500 4.7 2.5 2.89 ---- NR

1122-TeCA 167.9 +I 1.60 2,962 5.9 0.44 2.39 1.9 NR

1112-TeCA 167.9 +I 1.54 1,100 11.9 2.4 ---- ---- NR

111-TCA 133.4 0 1.35 1,495 123.8 14.5 2.49 2.25 0.2

112-TCA 133.4 0 1.44 4,394 24.2 0.96 2.38 ---- 0.005

12-DCA 99.0 -I 1.25 8,606 79.0 1.2 1.48 1.52 0.005

11-DCA 99.0 -I 1.17 4,676 227 6.2 1.79 ---- NR

CA 64.5 -II 0.90 5,700 120 1.8 1.43 ---- NR

Chlorinated Ethenes

PCE 165.8 +II 1.63 150 18.1 26.3 2.88 2.29 0.005

TCE 131.4 +I 1.46 1,100 74.2 11.7 2.53 1.53 0.005

cis-DCE 96.9 0 1.28 3,500 203 7.4 1.86 ---- 0.07

trans-DCE 96.9 0 1.26 6,260 333 6.8 1.93 ---- 0.1

11-DCE 96.9 0 1.22 3,344 604 23.0 2.13 ---- 0.007

VC 62.5 -I 0.91 2,763 2,660 79.2 1.38 ---- 0.002

aAverage value calculated using oxidation states for H I and Cl I.bWhen available, log(Koc) values were obtained from Nguyen et al. (2005).cSource: USEPA (2003).dMCL for total trihalomethanes, which is defined as the summed concentration of chloroform, bromoform (CHBr3),bromodichloromethane (CHBrCl2), and dibromochloromethane (CHBr2Cl).eNR Not regulated.fReported vapor pressure for solid-phase hexachloroethane.Notes: atm -- atmosphere; g -- gram; Kow -- octanol/water partitioning coefficient; Koc -- soil organic carbon/waterpartitioning coefficient; L -- liter; MCL -- maximum contaminant level; mg -- milligram; mL -- milliliter; mol -- mole.

Water

SoilAir

KH

p

S, KOW, KOCp

S@

Figure 2.3. The three major phases present in the subsurface and the properties of chlorinatedsolvents that govern the partitioning between these phases.


Chlorinated solvents are typically discharged into the environment as pure organic liquids or asmixtures of several organic liquids. The process through which these organic phases aregradually released into groundwater is referred to as dissolution.

For a chlorinated solvent, the extent of dissolution is controlled by the solvents aqueoussolubility (S), defined as the maximum amount of a chlorinated solvent that will partitioninto water at a given temperature (Lyman, 1982). Also referred to as saturation concentra-tions (Schwarzenbach et al., 2003), aqueous solubilities are typically reported with units ofmoles of chlorinated solvent per liter of water (molarity or M) or milligrams of chlorinatedsolvent per liter of water (mg/L, which is equivalent to parts per million [ppm]). Mostchlorinated solvents can be classified as sparingly soluble in water, with aqueous solubilitiesgenerally on the order of several tens to hundreds of mg/L (Table 2.2). However, theiraqueous solubilities are high relative to their established USEPA MCLs (Pankow and Cherry,1996), which contributes to their prominence as groundwater pollutants. Another conse-quence of their limited solubility is their tendency to occur in the subsurface as a separateliquid phase at the base of an aquifer commonly referred to as dense nonaqueous phaseliquid (DNAPL).

Table 2.2 reveals the general solubility trend among chlorinated solvents- as the numberof chlorine atoms on a compound increases, the aqueous solubility of that species decreases.This inverse relationship illustrates the influence that molecular size (specifically molarvolume [Horvath et al., 1999]) exerts on the miscibility of a chlorinated solvent in water.Environmental variables also can influence chlorinated solvent solubility. One such variable istemperature, although changes in the solubility of most chlorinated solvents are relativelyminor over environmentally relevant temperature ranges (Horvath, 1982). Another importantvariable is salinity; an increased concentration of dissolved salts results in a moderatedecrease in chlorinated solvent solubility (Lyman, 1982). The presence of other organicchemicals (referred to as co-solutes) also can increase the saturation concentration ofchlorinated solvents in water, behavior that is utilized for the treatment of chlorinatedsolvents during surfactant-enhanced aquifer remediation (SEAR) (e.g., Pennell et al., 1994;Fountain et al., 1996).

2.3.2 Solid-Water Partitioning

Partitioning of chlorinated solvents between aquifer solids and water plays an importantrole in contaminant fate and treatability because it affects the rate of transport in thesubsurface. As a class, chlorinated solvents can be considered moderately hydrophobic;although they partition (or sorb) onto aquifer solids, their affinity for such processes is notas great as that for other organic pollutants such as polycyclic aromatic hydrocarbons (PAHs)or polychlorinated biphenyls (PCBs).

A practical measure of a compounds hydrophobicity is the octanol-water partitioningcoefficient (Kow). For a two-phase system containing octanol and water, values of Kow aredefined as the equilibrium concentration of the chlorinated solvent in octanol relative to itsequilibrium concentration in water (Equation 2.1).

Kow CoctanolCwater

(Eq. 2.1)

For laboratory investigations of hydrophobicity, octanol is chosen as a convenient referencesolvent because it is immiscible with water. By definition, large values of Kow correspond tohydrophobic chemicals that are expected to sorb to soils and sediments more readily.


More pertinent for describing processes in the subsurface are values of Koc, whichrepresent a measure of a chemicals equilibrium partitioning between water and the organiccarbon fraction of aquifer solids (Equation 2.2).

Koc Corganic carbonCwater

(Eq. 2.2)

Accordingly, a key factor controlling the extent of chlorinated solvent sorption is theorganic carbon content of the subsurface material and the dissolved organic matter. Oftentimes, values of Koc can be estimated using linear correlations developed between log(Kow) andlog(Koc) for a given pollutant class.

In Table 2.2, values of both Kow and Koc generally increase as the number of chlorinesubstituents on a compound increases. These larger values of solid-water partitioning coeffi-cients will result in slower rates of subsurface transport. An inverse relationship betweenaqueous solubility and Kow (or Koc) values is also observed in Table 2.2; chemicals with limitedaqueous solubilities generally prefer to partition into a phase such as octanol or soil organicmatter rather than associate with water.

2.3.3 Air-Water Partitioning

Chlorinated solvents are relatively volatile compounds. Accordingly, air-water partitioningis expected to take place when contaminated groundwater comes into contact with air, as is thecase in unsaturated subsurface zones (e.g., the vadose zone). In such instances, the equilibriumpartitioning between air and water is typically described by Henrys Law, which is applicable todilute solutions of a chlorinated solvent in water. The Henrys Law constant, KH, relates theequilibrium concentration of the chlorinated solvent in air to its equilibrium concentration inwater (Equation 2.3).

KH CairCwater

(Eq. 2.3)

By definition, large KH values indicate a chemicals preference to partition from water intoair, although additional chemical properties and several environmental factors will also influ-ence the volatility of a species (Thomas, 1982a).

In Table 2.2, KH values are reported with units of atmm3/mol, but KH values also are

commonly reported with alternative units that depend upon the conventions used to report thechlorinated solvents concentrations in air and water. Unlike reported values of S, Kow and Koc,the KH values presented in Table 2.2 do not reveal any significant trends within or across thedifferent classes of chlorinated solvents.

2.3.4 Solid-Air Partitioning

The last chlorinated solvent partitioning process to consider is that between aquifer solidsand air, a topic covered in detail by Thomas (1982b). As with volatilization between air andwater, several chemical and environmental factors are at play in solid-air partitioning processes(Thomas, 1982b), but our mechanistic understanding of this process is rather limited. Onenoteworthy variable is the vapor pressure (p) of a chlorinated solvent, which represents themaximum attainable concentration of a chlorinated solvent in air (Schwarzenbach et al., 2003).Compounds with high values of p (which has units of torr or atm) tend to partition more


readily between air and sediments (and similarly, between air and water), and empiricalrelationships have been developed to estimate the rates at which such partitioning processesoccur (Thomas, 1982b). Values of p tend to decrease with increasing chlorination, althoughexceptions to this generalization are frequently observed (e.g., compare the p values forchloroethane and 1,1,2-trichloroethane in Table 2.2).

2.3.5 Transformation Reactions

Not included in Figure 2.3 is an additional critical pathway that impacts chlorinated solventfate in groundwater, that of transformation reactions. Rates and products of transformationreactions will depend upon many of the chemical and physical properties discussed above, aswell as the average oxidation state of carbon in the chlorinated solvent (Table 2.2). The carbonoxidation state is a measure of the number of electrons associated with the carbon atomsin a chlorinated solvent; this value ranges from I to +IV for the chlorinated solvents listed inTable 2.2. The more negative the oxidation state, the more electrons associated with the carbonatom. A positive oxidation state (e.g., carbon tetrachloride with a +IV) corresponds to a speciesin a highly oxidized form that is prone to reduction (gaining electrons). On the other hand,chlorinated solvents with more reduced carbon centers, such as vinyl chloride (C oxidation stateof I), are more susceptible to being oxidized (losing electrons).

From a practical sense, transformation reactions are often classified as either biotic orabiotic. Biotic reactions are typically those that involve microbial processes associated withbacterial metabolism, whereas abiotic reactions are defined as those processes that involveanother chemical species. The distinction, however, can become blurred when discussingchemicals such as biological exudates or minerals formed as a direct result of microbial activityor as an indirect result of biological modification of a chemical environment.

The classification does, however, provide a convenient organizational structure for dis-cussing the principles of chlorinated solvent remediation, and it has been adopted for use by theauthors in Chapter 4. Chapter 3 discusses microbially driven processes, including cometabolicreductive reactions, oxidative metabolism, and dehalorespiration. Chapter 4 describes the impor-tant abiotic processes for chlorinated solvents, including sorption, volatilization and transforma-tion reactions such as substitution, elimination, oxidation and reduction. Chapter 5 examines thepractical challenges for site remediation that result from the properties and behavior ofchlorinated solvents.

REFERENCES

ATSDR (Agency for Toxic Substances and Disease Registry). 1992. Toxicological profilefor 1,2,3-trichloropropane. U.S. Department of Health and Human Services ATSDRPublic Health Service, Atlanta, GA, USA. http://www.atsdr.cdc.gov/toxprofiles/tp57.pdf.Accessed January 11, 2010.

Baird C, Cann M. 2005. Environmental Chemistry, 3rd ed. W.H. Freeman and Company,New York, NY, USA. 652 p.

Fetter CW. 1999. Contaminant Hydrogeology, 2nd ed. Prentice-Hall, Inc., Upper Saddle River,NJ, USA. 500 p.

Fountain JC, Starr RC, Middleton T, Beikirch M, Taylor C, Hodge D. 1996. A controlled fieldtest of surfactant-enhanced aquifer remediation. Ground Water 34:910916.

Horvath AL. 1982. Halogenated Hydrocarbons: Solubility-Miscibility with Water. MarcelDekker, New York, NY, USA. 889 p.


Horvath AL, Getzen FW, Maczynska Z. 1999. IUPAC-NIST solubility data series 67.Halogenated ethanes and ethenes with water. J Phys Chem Ref Data 28:395628.

Lyman WJ. 1982. Solubility in Water. In Lyman WJ, Reehl WF, Rosenblatt DH, eds, Handbookof Chemical Property Estimation Methods: Environmental Behavior of OrganicCompounds. McGraw-Hill, New York, NY, USA, pp 151.

Mackay D, Shiu WY, Ma KC. 1993. Illustrated Handbook of Physical-Chemical Properties andEnvironmental Fate for Organic Chemicals. Lewis Publishers, Chelsea, MI, USA.

Nguyen TH, Goss K, Ball WP. 2005. Polyparameter linear free energy relationships forestimating the equilibrium partition of organic compounds between water and the naturalorganic matter in soils and sediments. Environ Sci Technol 39:913924.

Pankow JF, Cherry JA. 1996. Dense Chlorinated Solvents and Other DNAPLs in Groundwater:History, Behavior, and Remediation. Waterloo Press, Portland, OR, USA. 525 p.

Pennell KD, Jin M, Abriola LM, Pope GA. 1994. Surfactant enhanced remediation of soilcolumns contaminated by residual tetrachloroethylene. J Contam Hydrol 16:3553.

Schwarzenbach RP, Gschwend PM, Imboden DM. 2003. Environmental Organic Chemistry.John Wiley & Sons, Inc., Hoboken, NJ, USA. 1313 p.

Thomas RG. 1982a. Volatilization from Water. In Lyman WJ, Reehl WF, Rosenblatt DH, eds,Handbook of Chemical Property Estimation Methods: Environmental Behavior of OrganicCompounds. McGraw-Hill, New York, NY, USA, pp 15.115.34.

Thomas RG. 1982b. Volatilization from Soil. In Lyman WJ, Reehl WF, Rosenblatt DH, eds,Handbook of Chemical Property Estimation Methods: Environmental Behavior of OrganicCompounds, McGraw-Hill, New York, NY, USA, pp 16.116.50.

USEPA (U.S. Environmental Protection Agency). 2003. Ground Water and Drinking Water.National Primary Drinking Water Standards. EPA-816-F-03-016. USEPA, Office of Water,Washington, DC, USA.

Vollhardt KPC, Schore NE. 1994. Organic Chemistry. W.H. Freeman and Company, New York,NY, USA. 1156 p.


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Chapter 2: Chlorinated Solvent Chemistry: Structures, Nomenclature and Properties2.1 INTRODUCTION2.2 Structure and Nomenclature2.3 Properties2.3.1 Dissolution2.3.2 Solid-Water Partitioning2.3.3 Air-Water Partitioning2.3.4 Solid-Air Partitioning2.3.5 Transformation Reactions

References

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