Experimentally determined Henry's law constants for 17 polychlorobiphenyl congeners

Dunnivant, Frank M.; Coates, John T.; Elzerman, Alan W.

doi:10.1021/es00169a013

Cited by 64 publications

(81 citation statements)

References 19 publications

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“…PCBs were initially quantified using a gas chromatograph (Hewlett-Packard 6890) equipped with an achiral column (30 m × 0.25 mm × 0.25 µm, ZB5, Phenomenex), and a 63 Ni electron-capture detector (ECD) according to the method of Dunnivant and Elzerman (23) as modified by Farley et al (5). Helium (2 mL/min) was used as a carrier gas, with the same temperature program and instrument conditions as previously described (23), except that the initial hold time was changed to 2.5 min. Products of the dechlorination of the two chiral hexachlorobiphenyls PCB132 and PCB149 were predicted by assuming that only meta or para dechlorination occurred.…”

Section: Methodsmentioning

confidence: 99%

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Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Pakdeesusuk

Jones

Lee

et al. 2003

Environ. Sci. Technol.

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The enantioselectivity of microbial reductive dechlorination of chiral PCBs in sediments from Lake Hartwell, SC, was determined by microcosm studies and enantiomer-specific GC analysis. Sediments from two locations in the vicinity of the highest levels of PCB contamination were used as inocula. Dechlorination activity was monitored by concentration decreases in the spiked chiral PCBs and formation of dechlorination products using both achiral and chiral chromatography. Live microcosms spiked with PCB132 (234-236) exhibited dechlorination of PCB132 to PCB91 (236-24) and PCB51 (24-26). Meta dechlorination was the dominant mechanism. Microcosms spiked with PCB149 (245-236) exhibited preferential para dechlorination of PCB149 to PCB95 (236-25), followed by meta dechlorination to PCB53 (25-26) and subsequently PCB19 (26-2). Dechlorination of chiral PCB132 and PCB149 was not enantioselective. In Aroclor 1254-spiked microcosms, reductive dechlorination of PCB149 also was nonenantioselective. These results suggest that dechlorinating enzymes responsible for the dehalogenation of the chiral PCB132 and PCB149 congeners bind the two enantiomers equally. Reductive dechlorination of PCB91 and PCB95, however, occurred in an enantioselective manner, indicating that the dechlorinating enzymes for these PCBs are enantiomer-specific. The chlorine substitution pattern on the biphenyl ring appears to influence whether reductive dechlorination of chiral PCB congeners is enantioselective. Enantioselective PCB dechlorination by the microbial population of Lake Hartwell sediments occurs for select chiral PCBs; thus, certain chiral PCBs might be useful as markers for in situ reductive dechlorination.

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Section: Methodsmentioning

confidence: 99%

“…Four-point calibration curves for identified products were built using aldrin (AccuStandard, Inc.) as an internal standard. PCB congeners in Aroclor 1254 were identified and quantified using the methods described previously (5,18,20,23). Chiral Chromatography.…”

Section: Methodsmentioning

confidence: 99%

Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Pakdeesusuk

Jones

Lee

et al. 2003

Environ. Sci. Technol.

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“…Calculation or estimation ofwater solubilities from theoretical and empirical considerations is an active area of research, and some progress has been made using molecular surface area and volume and activities oforganic solutes in organic phase and activity coefficients in aqueous phase (20)(21)(22). The wide range of solubilities ofthese essentially hydrophobic compounds and the very low solubilities for compounds in the medium to higher molecular weight range, e.g., phenanthrene and 2,2',4,4',5,5'-hexachlorobiphenyl, are illustrated by the examples in Table 1 (35)(36)(37) but relatively few types of compounds have been studied.…”

Section: Physical Chemical Researchmentioning

confidence: 99%

Biogeochemical Processes Governing Exposure and Uptake of Organic Pollutant Compounds in Aquatic Organisms

Farrington¹

1991

Environmental Health Perspectives

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This paper reviews current knowledge of biogeochemical cycles of pollutant organic chemicals in aquatic ecosystems with a focus on coastal ecosystems. There is a bias toward discussng chemkal and geochemical aspects ofbiogeochemical cycles and an emphasis on hydrophobic organic compounds such as polynuckar aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated organic compounds used as pesticides. The complexity of mixtures of pollutant organic compounds, their various modes ofentering ecosystems, and their physical chemical forms are discussed. Important factors that influence bioavailability and disposition (e.g., organism-water partitioning, uptake via food, food meb transfer) are reviewed. These factors include solubilities ofchemicals; partitioning ofchemicals between solid surfaces, colloids, and soluble phases; variables rates of sorption, desorption; and physiological status of organism. It appears that more emphasis on considering food as a source of uptake and bioaccumulation is important in benthic and epibenthic ecosystems when sediment-associated pollutants are a nt source ofinput to an aquatic ecosystem. Progress with mathematical models for exposure and uptake of contaminant chemicals is discussed briefly.

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“…This latter paper clearly comes closest to addressing the concerns over possible aggregation, but does not meet the strict criterion of demonstrating concentration independence of the Henry's law constants. However the two values of DG s for compounds in the test set reported by Dunnivant et al [23], at concentrations less than half ''saturated'' were 0.61 kcal/mol less negative than a value based on the generator column technique [20], and within 0.1 kcal/mol of a value [24] based on solutions well below the solubility limit and never exposed to excess compound. If the solubility is spuriously high, then the solvation free energy will be spuriously negative.…”

Section: Transfer Energiesmentioning

confidence: 62%

“…The problem goes on because some direct measurements of Henry's law constants start with ''saturated solutions'' prepared using a generator column and may be subject to the same systematic error problem. For those polychlorinated biphenyls in the test set where direct determination of Henry's law constants has been reported, two papers were based on solutions prepared using generator columns [20,21], one was based on solutions prepared by stirring with excess organic compound and then let stand [22], and one was based on solutions made with enough organic solute to give a solution less than half saturated based on reported solubilities [23]. This latter paper clearly comes closest to addressing the concerns over possible aggregation, but does not meet the strict criterion of demonstrating concentration independence of the Henry's law constants.…”

Section: Transfer Energiesmentioning

confidence: 99%

The SAMPL3 blind prediction challenge: transfer energy overview

Geballe

Guthrie

2012

J Comput Aided Mol Des

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Prediction of the free energy of solvation of a small molecule, or its transfer energy, is a necessary step along the path towards calculating the interactions between molecules that occur in an aqueous environment. A set of these transfer energies were gathered from the literature for series of chlorinated molecules with varying numbers of chlorines based on ethane, biphenyl, and dibenzo-p-dioxin. This focused set of molecules were then provided as a blinded challenge to assess the ability of current computational solvation methods to accurately model the interactions between water and increasingly chlorinated compounds. This was presented as part of the SAMPL3 challenge, which represented the fourth iterative blind prediction challenge involving transfer energies. The results of this exercise demonstrate that the field in general has difficulty predicting the transfer energies of more highly chlorinated compounds, and that methods seem to be erring in the same direction.

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Experimentally determined Henry's law constants for 17 polychlorobiphenyl congeners

Cited by 64 publications

References 19 publications

Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Biogeochemical Processes Governing Exposure and Uptake of Organic Pollutant Compounds in Aquatic Organisms

The SAMPL3 blind prediction challenge: transfer energy overview

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