Enantioselective Toxicity Effects of 2,2',3,5',6-Pentachloro Biphenyl (PCB-95) on Developing Brains in Zebrafish Larvae

Effects of polystyrene nanoplastics and PCB-44 exposure on growth and physiological biochemistry of Chlorella vulgaris

Both NPs and PCBs are emerging contaminants widely distributed in the environment, and it is worth exploring whether the combination of the two contaminants causes serious pollution and harm. Therefore, we studied the effects of PS-NPs and PCB-44 alone and together after 96 h and 21 d of exposure to C. pyrenoidosa. The results showed that PS-NPs and PCB-44 affected the cell cycle of C. pyrenoidosa and inhibited its normal growth. Under PS-NPs and PCB-44 stress, the relative conductivity of the algal solution increased, the hydrophobicity of the algal cell surface decreased, and the synthesis of chlorophyll a and chlorophyll b was reduced. In addition to physiological, there are biochemical effects on C. pyrenoidosa. PS-NPs and PCB-44 exposure induced oxidative stress with significant changes in the enzymatic activities of SOD and CAT together with MDA content. Moreover, the relative expression of photosynthesis-related genes (psbA, rbcL, rbcS) all responded, negatively affecting photosynthesis. In particular, significant toxic effects were observed with single exposure to PCB-44 and co-exposure to PS-NPs and PCB-44, with similar trends of effects in acute and chronic experiments. Taken together, exposure to PS-NPs and PCB-44 caused negative effects on the growth and physiological biochemistry of C. pyrenoidosa. These results provide scientific information to further explore the effects of NPs and PCBs on aquatic organisms and ecosystems.

Chiral signatures of polychlorinated biphenyls in serum from e-waste workers and their correlation with hydroxylated metabolites

Elevated concentrations of polychlorinated biphenyls (PCBs) found in environmental media and biota from typical e-waste dismantling sites have raised concerns regarding their human body burden and potential negative health effects. In the present study, the enantiomeric compositions of three typical chiral congeners (PCB-95, PCB-132, and PCB-149) were measured in 24 serum samples from e-waste workers by using gas chromatography coupled to triple quadrupole tandem mass spectrometry. The mean enantiomer fractions (EFs) of chiral congeners in serum from the workers were 0.655 ± 0.103, 0.679 ± 0.164, and 0.548 ± 0.095 for PCB-95, PCB-132, and PCB-149, respectively. The (+) enantiomers of PCB-95, PCB-132, and PCB-149 were enantioselectively enriched in serum. Significant positive correlations were observed between the EF of the chiral congener PCB-95 and the total concentration of OH-PCBs, suggesting that EF values of chiral PCBs could be used to indicate the extent of biological metabolism. In addition, the EF of PCB-95 in serum samples increased with increasing work duration of the e-waste workers, thus demonstrating the usefulness of EF values of chiral PCBs as tracers of human exposure to PCBs. Because of the enantioselective enrichment of (+) enantiomers of PCB-95, PCB-132, and PCB-149, further studies are needed to explore the metabolism and toxicity of chiral contaminants in humans.