Do Bird Assemblages Predict Susceptibility by E-Waste Pollution? A Comparative Study Based on Species- and Guild-Dependent Responses in China Agroecosystems

Indirect effects of electronic waste (e-waste) have been proposed as a causal factor in the decline of bird populations, but analyses of the severity impacts on community assembly are currently lacking. To explore how population abundance/species diversity are influenced, and which functional traits are important in determining e-waste susceptibility, here we surveyed breeding and overwintering birds with a hierarchically nested sampling design, and used linear mixed models to analyze changes in bird assemblages along an exposure gradient in South China. Total bird abundance and species diversity decreased with e-waste severity (exposed < surrounding < reference), reflecting the decreasing discharge and consequent side effects. Twenty-five breeding species exclusively used natural farmland, and nine species decreased significantly in relative abundance at e-waste polluted sites. A high pairwise similarity between exposed and surrounding sites indicates a diffuse effect of pollutants on the species assembly at local scale. We show that sensitivity to e-waste severity varies substantially across functional guild, with the prevalence of woodland insectivorous and grassland specialists declining, while some open farmland generalists such as arboreal frugivores, and terrestrial granivores were also rare. By contrast, the response of waterbirds, omnivorous and non-breeding visitors seem to be tolerable to a wide range of pollution so far. These findings underscore that improper e-waste dismantling results in a severe decline of bird diversity, and the different bird assemblages on polluted and natural farmlands imply species- and guild-dependent susceptibility with functional traits. Moreover, a better understanding of the impact of e-waste with different pollution levels, combined multiple pollutants, and in a food-web context on bird is required in future

Bioaccumulation and Biotransformation of Chlorinated Paraffins

Chlorinated paraffins (CPs), a class of persistent, toxic, and bioaccumulated compounds, have received increasing attention for their environmental occurrence and ecological and human health risks worldwide in the past decades. Understanding the environmental behavior and fate of CPs faces a huge challenge owing to the extremely complex CP congeners. Consequently, the aims of the present study are to summarize and integrate the bioaccumulation and biotransformation of CPs, including the occurrence of CPs in biota, tissue distribution, biomagnification, and trophic transfer, and biotransformation of CPs in plants, invertebrates, and vertebrates in detail. Biota samples collected in China showed higher CP concentrations than other regions, which is consistent with their huge production and usage. The lipid content is the major factor that determines the physical burden of CPs in tissues or organs. Regarding the bioaccumulation of CPs and their influence factors, inconsistent results were obtained. Biotransformation is an important reason for this variable. Some CP congeners are readily biodegradable in plants, animals, and microorganisms. Hydroxylation, dechlorination, chlorine rearrangement, and carbon chain decomposition are potential biotransformation pathways for the CP congeners. Knowledge of the influence of chain length, chlorination degree, constitution, and stereochemistry on the tissue distribution, bioaccumulation, and biotransformation is still scarce

Biodegradation of typical BFRs 2,4,6-tribromophenol by an indigenous strain Bacillus sp. GZT isolated from e-waste dismantling area through functional heterologous expression

Legacy wastewater contaminants from e-waste dismantling process such as 2,4,6-tribromophenol (TBP), one of the most widely used brominated flame retardants (BFRs), have raised concern owing to their toxicity and recalcitrance. Our previously isolated Bacillus sp. GZT from river sludge in e-waste dismantling area is a good candidate for bioremediation of BFRs contaminated sites considering its remarkable degradability of TBP and its intermediates. However, there exists a new challenge because bio-degrader cannot produce enough biomass or metabolic activity to cleanup TBP in practice complex environment. Here, we heterologously expressed and functionally characterized the genes and enzymes responsible for TBP degradation to examine the feasibility of enhancing the ability of this microorganism to detoxify TBP. Results demonstrated that five recombinant strains containing functional genes, designated tbpA, tbpB, tbpC, tbpD, and tbpE, become more tolerant toward a wide range of brominated compounds than the nontransgenic strain. Cytochrome P450 reductase encoded by tbpA gene could greatly increase efficiency to remove TBP (98.8%), as compared to wild-type strain GZT (93.2%). Its debromination intermediates 2,4-dibromophenol, 2,6-dibromo-4-methylphenol and 2-bromophenol were significantly metabolized by halophenol dehalogenases encoded by tbpB, tbpC, and tbpD, respectively. Finally, under the function of tbpE gene encoding enzyme, further debrominated product (phenol) was dramatically detoxified. To reduce the risk of these xenobiotics, the expression of these genes can be induced and significantly up-regulated during exposure to them. These results open broad scope for future study in developing genetic engineering technologies for more efficient remediation wastewater of e-waste recycling sites contaminated with TBP, which would certainly be important steps to lower TBP exposures and prevent potential health effects. (C) 2019 Elsevier B.V. All rights reserved

Size-dependent concentrations and bioaccessibility of organophosphate esters (OPEs) in indoor dust: A comparative study from a megacity and an e-waste recycling site

Indoor dust ingestion is an important pathway in human exposure to environmental pollutants, and the bioaccessibility of pollutants can largely influence human exposure risk assessment. In the present study, the concentrations and compositions of organophosphate esters (OPEs) were investigated for different sizes (50 mu m to 2 mm) of indoor dust collected from a megacity, Guangzhou, and an e-waste recycling site. The concentrations of total OPEs were 5360 to 6830 ng/g and 560 to 20,500 ng/g across all sizes of dust from Guangzhou and the e-waste site, respectively. The levels and compositions of OPEs were consistent in different fractions of dust from Guangzhou. The highest concentrations of OPEs were found in the finest fraction of dust from the e-waste site. OPEs in Guangzhou dust showed decreasing bioaccessibility when the log KOW of FRs increased from 4 to 11. The bioaccessibility of most OPEs in dust from the e-waste site was much lower than those in Guangzhou dust, indicating low bioaccessibility in the components of dust, such as e-waste debris, from the e-waste site. The human exposure risks of OPEs in dust from Guangzhou were generally higher than those in dust from the e-waste site. Chitosan and montmorillonite could significantly decrease the bioaccessibility of all OPEs, except for tri-ethyl phosphate (TEP) and tris-(2-butoxyethyl)phosphate (TBOEP) in dust (p < 0.05), indicating chitosan and montmorillonite as promising food additives to enhance the elimination of OPEs. (c) 2018 Elsevier B.V. All rights reserved

Genome sequence of a spore-laccase forming, BPA-degrading Bacillus sp. GZB isolated from an electronic-waste recycling site reveals insights into BPA degradation pathways

Bisphenol A (BPA) is a synthetic chemical with known deleterious effects on biota. A genome sequencing project is an important starting point for designing a suitable BPA bioremediation process, because it provides valuable genomic information about the physiological, metabolic, and genetic potential of the microbes used for the treatment. This study explored genomic insights provided by the BPA-degrading strain Bacillus sp. GZB, previously isolated from electronic-waste-dismantling site. The GZB genome is a circular chromosome, comprised of a total of 4,077,007bp with G+C content comprising 46.2%. Genome contained 23 contigs encoded by 3881 protein-coding genes with nine rRNA and 53 tRNA genes. A comparative study demonstrated that strain GZB bloomed with some potential features as compared to other Bacillus species. In addition, strain GZB developed spore cells and displayed laccase activity while growing at elevated stress levels. Most importantly, strain GZB contained many protein-coding genes associated with BPA degradation, as well as the degradation of several other compounds. The protein-coding genes in the genome revealed the genetic mechanisms associated with the BPA degradation by strain GZB. This study predicts four possible degradation pathways for BPA, contributing to the possible use of strain GZB to remediate different polluted environments in the future