Dietary accumulation and quantitative structure‐activity relationships for depuration and biotransformation of short (C₁₀), medium (C₁₄), and long (C₁₈) carbon‐chain polychlorinated alkanes by juvenile rainbow trout (Oncorhynchus mykiss)

Abstract

Abstract-Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three [ 14 C]-polychlorinated alkanes (PCAs) (C 10 H 15.3 Cl 6.7 , C 14 H 23.3 Cl 6.7 , and C 18 H 31.4 Cl 6.6 ) at nominal concentrations of 1.5 and 15 g/g for 40 d, followed by 160 d of clean food, to measure bioaccumulation parameters and biotransformation. These PCAs are identical in carbon-chain length and chlorine content to industrial chlorinated paraffin products, although their method of synthesis differs from that of chlorinated paraffin products. Half-lives ranged from 26 to 91 d, biomagnification factors ranged from 0.9 to 2.8, and both exhibited increasing trends with increasing carbon-chain length. Data from this work and others on PCAs were used to determine biotransformation rates and to examine quantitative structure-activity relationships for bioaccumulation and biotransformation. Quantitative structure-activity relationships developed for half-life and biomagnification factor showed positive linear relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log K ow . The PCA biotransformation rates (per day) ranged from Ϫ0.00028 to 8.4 and exhibited negative relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log K ow . Results suggest that PCAs with a total number of carbon and chlorine atoms between 22 and 30 are slowly, or are not, biotransformed in juvenile rainbow trout. Increasing carbon-chain length and chlorine content result in greater bioaccumulation of PCAs by reducing partition-based (i.e., diffusion) and metabolic (i.e., biotransformation) elimination processes. High bioaccumulation potential and low biotransformation rates of medium (C 14-18 ) and long (C 18-30 ) carbon-chain PCAs and highly chlorinated PCAs indicate that information is needed regarding the environmental concentrations of these PCAs in aquatic food chains.

Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica

“…A similar pattern of decreasing BMFs with the increasing carbon chain length of SCCP congeners was observed in a food web from Lake Michigan (Houde et al, 2008). However, in previous laboratory exposure experiments, the BMFs tended to increase with increasing lengths of the carbon chain (Fisk et al, 1998;Fisk et al, 2000). Notably, the biomagnification of shorter chain congeners of SCCPs was higher than that of the longer chain ones in the field study, which might be attributed to the larger molecular sizes of the longer carbon chain congeners, as Mackintosh et al (2004) found that the concentrations of high molecular-weight phthalate esters declined significantly at higher trophic levels in a marine food web from western Canada.…”

In vitro‐in vivo extrapolation of quantitative hepatic biotransformation data for fish. II. Modeled effects on chemical bioaccumulation

“…26,2007 J.W. Low (0.0-0.0084/d) rates of metabolism were exhibited by juvenile trout exposed to a series of polychlorinated alkanes [49]. One potential use of these models is to perform in vitro-in vivo metabolism comparisons with fish.…”

Short-chain chlorinated paraffins in terrestrial bird species inhabiting an e-waste recycling site in South China

“…Metabolism of chlorinated paraffins in organisms has been noted in several studies. For example, Fisk et al (2000) and Vaughan and Hurd (2010) observed significant biotransformation of chlorinated alkanes in rainbow trout (Oncorhynchus mykiss). Houde et al (2008) also found that lake trout metabolize SCCPs.…”