Bioaccumulation of Persistent Halogenated Organic Pollutants in Insects: Common Alterations to the Pollutant Pattern for Different Insects during Metamorphosis

Few studies have examined the accumulation and fate of persistent halogenated organic pollutants (HOPs) in insects. We measured HOPs, including dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls, and halogenated flame retardants, in insects from four taxonomic groups collected from an e-waste site. Dragonfly larvae collected from a pond contained the highest concentrations of all chemicals except DDTs, while the litchi stinkbugs contained the lowest. Different insect taxa exhibited different contaminant patterns which could be attributed to their habitats and feeding strategies. Bioaccumulation factors for dragonfly larvae and biomagnification factors for moth and grasshopper larvae were significantly positively correlated with the octanol–water partition coefficient of the chemicals (log <i>K</i>_OW < 8). Common nonlinear correlations between the ratio of larval to adult concentrations and log <i>K</i>_OW were observed for all taxa studied. The ratio of concentrations decreased with increasing values of log <i>K</i>_OW (log <i>K</i>_OW < 6–6.5), then increased (6 < log <i>K</i>_OW < 8) and decreased again (log <i>K</i>_OW > 8). This result implies that the mechanism that regulates organic pollutants in insects during metamorphosis is common to all the taxa studied

Using Compound-Specific Stable Carbon Isotope Analysis to Trace Metabolism and Trophic Transfer of PCBs and PBDEs in Fish from an e‑Waste Site, South China

Two fish species (mud carp and northern snakehead) forming a predator/prey relationship and sediment samples were collected from a pond contaminated by e-waste. The concentrations and stable carbon isotope ratios (δ¹³C) of individual polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) congeners were measured to determine if compound-specific carbon isotope analysis (CSIA) could be used to provide insight into the metabolism and trophic dynamics of PCBs and PBDEs. Significant correlations were found in the isotopic data of PCB congeners between the sediment and the fish species and between the two fish indicating identical origin of PCBs in sediment and fish. Most PCB congeners in the fish species were enriched in ¹³C compared with the PCB congeners in the sediments as a result of isotopic fractionation during the metabolism of PCBs in fish. The isotopic data of several PCB congeners showing isotopic agreement or isotopic depletion could be used for source apportionment or to trace the reductive dechlorination process of PCBs in the environment. The PCB isotopic data covaried more in the northern snakehead than in the mud carp when compared to the sediment, implying that a similar isotopic fractionation occurs from the prey to the predator fish for a PCB congener possibly due to similar metabolic pathways. The PBDE congener patterns differed in the three sample types with a high abundance of BDE209, 183, 99, and 47 in the sediment, BDE47, 153, and 49 in the mud carp and BDE47, 100, and 154 in the northern snakehead. The isotopic change of BDE congeners, such as BDE47 and BDE49, in two fish species, provides evidence for biotransformation of PBDEs in biota. The results of this study suggest that CSIA is a promising tool for deciphering the fate of PCBs and PBDEs in the environment

Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from E‑Waste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification

Hair is increasingly used as a biomarker for human exposure to persistent organic pollutants (POPs). However, the internal and external sources of hair POPs remain a controversial issue. This study analyzed polychlorinated biphenyls (PCBs) in human hair and serum from electronic waste recycling workers. The median concentrations were 894 ng/g and 2868 ng/g lipid in hair and serum, respectively. The PCB concentrations in male and female serum were similar, while concentrations in male hair were significantly lower than in female hair. Significant correlations between the hair and serum PCB levels and congener profiles suggest that air is the predominant PCB source in hair and that hair and blood PCB levels are largely dependent on recent accumulation. The PCB95, 132, and 183 chiral signatures in serum were significantly nonracemic, with mean enantiomer fractions (EFs) of 0.440–0.693. Nevertheless, the hair EFs were essentially racemic (mean EFs = 0.495–0.503). Source apportionment using the Chemical Mass Balance model also indicated primary external PCB sources in human hair from the study area. Air, blood, and indoor dust are responsible for, on average, 64.2%, 27.2%, and 8.79% of the hair PCBs, respectively. This study evidenced that hair is a reliable matrix for monitoring human POP exposure