Abstract-Dietary accumulation of 23 hydrophobic organochlorines (OCs) by juvenile rainbow trout (Oncorhynchus mykiss) was studied with the objective of obtaining relationships between bioaccumulation parameters and the octanol/water partition coefficient (K ow ). A wide range of OCs were used including 16 polychlorinated biphenyls (PCBs 18,28,44,52, 66, 101, 105, 118, 128, 138, 153, 187, 189, 195, 206, and 209), hexachlorobenzene, mirex, tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMeOH), and three toxaphene congeners (Cl 7 -chlorobornane [CHB] [Hp-sed], Cl 8 -CHB [T2], and Cl 9 -CHB [T12]). Tris(4-chlorophenyl)methane (half-life [t 1/2 ] ϭ 65 d) was more persistent than TCPMeOH (t 1/2 ϭ 20 d), and TCPMe was not biotransformed to TCPMeOH by rainbow trout. Cl 7 -chlorobornane (t 1/2 ϭ 32 d) was more rapidly eliminated, and appears to be more readily metabolized, than Cl 8 -CHB (t 1/2 ϭ 43 d) and Cl 9 -CHB (t 1/2 ϭ 42 d). With the exception of TCPMeOH, Cl 7 -CHB, and PCB 18, all of the OCs had biomagnification factors (BMFs) Ͼ1, implying a potential to biomagnify. Half-lives had a significant curvilinear relationship with K ow (R 2 ϭ 0.85, p Ͻ 0.001), with a maximum t 1/2 for OCs with log K ow ϳ 7.0. Decreasing t 1/2 for OCs of log K ow Ͼ 7.0 may be related to slow kinetics of these super hydrophobic OCs and the short exposure phase, which results in insufficient time for the super hydrophobic OCs to reach slower clearing compartments of the rainbow trout. Assimilation efficiency was not as well described by K ow as by t 1/2 and BMF, although a significant curvilinear relationship was observed (R 2 ϭ 0.53, p ϭ 0.004). The BMF had a significant curvilinear relationship with log K ow (R 2 ϭ 0.84, p Ͻ 0.001). Recalcitrant OCs with a log K ow of ϳ7.0 would appear to have the greatest potential for food chain biomagnification in fish.

A method for quantifying C 10 -C 13 polychloroalkanes (PCAs) in environmental samples by high-resolution gas chromatography/electron capture negative ion highresolution mass spectrometry in the selected ion monitoring (SIM) mode is presented. The molecular compositions of commercial PCAs and of PCA-containing extracts from environmental samples are first determined by monitoring [M -Cl] -ions of specific m/z value corresponding to formula groups present and by assuming that the integrated ion signals are proportional to molar concentration weighted by the number of chlorine atoms in the formula group. For quantitative measurement, one specific m/z peak is selected for each analyte and its SIM response is integrated. The integrated SIM responses have a linear dependence upon amount of PCA injected over the range 0.5-500 ng. An analytical protocol is then described. High-resolution (∼12 000 resolving power) mass spectrometry is shown to be desirable to eliminate self-interferences between PCAs at low resolving power (∼1000) and potential interferences from technical chlordane, toxaphene, PCBs, and other organochlorine pesticides. Extraction recoveries of PCAs from fish averaged

Dietary accumulation of 23 hydrophobic organochlorines (OCs) by juvenile rainbow trout (Oncorhynchus mykiss) was studied with the objective of obtaining relationships between bioaccumulation parameters and the octanol/water partition coefficient (Kow). A wide range of OCs were used including 16 polychlorinated biphenyls (PCBs 18, 28, 44, 52, 66, 101, 105, 118, 128, 138, 153, 187, 189, 195, 206, and 209), hexachlorobenzene, mirex, tris(4‐chlorophenyl)methane (TCPMe), tris(4‐chlorophenyl)methanol (TCPMeOH), and three toxaphene congeners (Cl7‐chlorobornane [CHB] [Hp‐sed], Cl8‐CHB [T2], and Cl9‐CHB [T12]). Tris(4‐chlorophenyl)methane (half‐life [t1/2] = 65 d) was more persistent than TCPMeOH (t1/2 = 20 d), and TCPMe was not biotransformed to TCPMeOH by rainbow trout. Cl7‐chlorobornane (t1/2 = 32 d) was more rapidly eliminated, and appears to be more readily metabolized, than Cl8‐CHB (t1/2 = 43 d) and Cl9‐CHB (t1/2 = 42 d). With the exception of TCPMeOH, Cl7‐CHB, and PCB 18, all of the OCs had biomagnification factors (BMFs) >1, implying a potential to biomagnify. Half‐lives had a significant curvilinear relationship with Kow (R2 = 0.85, p < 0.001), with a maximum t1/2 for OCs with log Kow ∼ 7.0. Decreasing t1/2 for OCs of log Kow > 7.0 may be related to slow kinetics of these super hydrophobic OCs and the short exposure phase, which results in insufficient time for the super hydrophobic OCs to reach slower clearing compartments of the rainbow trout. Assimilation efficiency was not as well described by Kow as by t1/2 and BMF, although a significant curvilinear relationship was observed (R2 = 0.53, p = 0.004). The BMF had a significant curvilinear relationship with log Kow (R2 = 0.84, p < 0.001). Recalcitrant OCs with a log Kow of ∼7.0 would appear to have the greatest potential for food chain biomagnification in fish.

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