Reproductive performance of Peregrine falcons relative to the use of organochlorine pesticides, 1946-2021.

Populations of some fish- and meat-eating birds suffered dramatic declines globally following the introduction of organochlorine pesticides during the late 1940s and 1950s. It has been hypothesised that these population declines during the 1950s-1970s were largely driven by a combination of reproductive failure due to eggshell-thinning, egg breakage and embryonic death attributable to DDT and its metabolites, and to enhanced mortality attributable to the more toxic cyclodiene compounds such as aldrin and dieldrin. Using 75 years (1946-2021) of Peregrine falcon (Falco peregrinus) monitoring data (315 unique nest-sites monitored for 6110 nest-years), we studied the breeding performance of a resident Peregrine population in southern Scotland relative to the spatiotemporal pattern of organochlorine pesticide use. We show that (i) Peregrine breeding success and measures of breeding performance increased substantially following the reduction in, and subsequently a complete ban on, the use of organochlorine pesticides; (ii) improvements in Peregrine breeding performance were more dramatic in southeastern Scotland where agriculture was the predominant land use than in southwestern Scotland where there was less arable and more forested land; (iii) Peregrines nesting closer to the coast generally had higher fledging success (that is, a higher proportion of clutches that produced at least one fledgeling) than those nesting inland farther away from the coast; (iv) low temperatures and excessive rain in May negatively affected Peregrine fledging success; and (v) Peregrine abundance increased in parallel with improvements in reproductive performance following the reduction and then complete ban on the use of organochlorine pesticides in the UK. However, recovery was gradual and occurred over four decades, and rate of recovery varied among measures of reproductive performance (egg, nestling and fledgeling production). Our results suggest that the temporal pattern of organochlorine pesticide use strongly influenced Peregrine reproductive parameters but that the pattern of influence differed regionally. Overall results are consistent with the hypothesis that reproductive failure caused by organochlorine pesticides was an important driver of the decline in the south Scottish Peregrine population, and that improvements in all measures of breeding performance following a reduction and eventual ban on organochlorine use facilitated the observed increase in this population.

Novel Use of Cell Profiling Technology to Visualize Mitochondrial Responses of Humpback Whale Fibroblasts to Chemical Exposure.

Cetaceans are at elevated risk of accumulating persistent and lipophilic environmental contaminants due to their longevity and high proportion of body fat. Despite this, there is a paucity of taxa-specific chemical effect data, in part due to the ethical and logistical constraints in working with highly mobile aquatic species. Advances in cetacean cell culture have opened the door to the application of mainstream in vitro toxicological effect assessment approaches. Image-based cell profiling is a high-throughput, microscopy-based system commonly applied in drug development. It permits the analysis of the xenobiotic effect on multiple cell organelles simultaneously, hereby flagging its potential utility in the evaluation of chemical toxicodynamics. Here we exposed immortalized humpback whale skin fibroblasts (HuWaTERT) to six priority environmental contaminants known to accumulate in the Southern Ocean food web, in order to explore their subcellular organelle responses. Results revealed chemical-dependent modulation of mitochondrial texture, with the lowest observed effect concentrations for chlorpyrifos, dieldrin, trifluralin, and p,p'-dichlorodiphenyldichloroethane of 0.3, 4.1, 9.3, and 19.8 nM, respectively. By contrast, no significant changes were observed upon exposure to endosulfan and lindane. This study contributes the first fixed mitochondrial images of HuWaTERT and constitutes novel, taxa-specific chemical effect data in support of evidence-based conservation policy and management.

Responses of Anabaena sp. PCC7120 to lindane: Physiological effects and differential expression of potential lin genes.

Lindane (γ-HCH) is an organochlorine pesticide that causes huge environmental concerns worldwide due to its recalcitrance and toxicity. The use of the cyanobacterium Anabaena sp. PCC 7120 in aquatic lindane bioremediation has been suggested but information relative to this process is scarce. In the present work, data relative to the growth, pigment composition, photosynthetic/respiration rate, and oxidative stress response of Anabaena sp. PCC 7120 in the presence of lindane at its solubility limit in water are shown. In addition, lindane degradation experiments revealed almost a total disappearance of lindane in the supernatants of Anabaena sp. PCC 7120 culture after 6 days of incubation. The diminishing in lindane concentration was in concordance with an increase in the levels of trichlorobenzene inside the cells. Furthermore, to identify potential orthologs of the linA, linB, linC, linD, linE, and linR genes from Sphingomonas paucimobilis B90A in Anabaena sp. PCC 7120, a whole genome screening was performed allowing the identification of five putative lin orthologs (all1353 and all0193 putative orthologs of linB, all3836 putative orthologs of linC, and all0352 and alr0353 putative orthologs of linE and linR, respectively) which could be involved in the lindane degradation pathway. Differential expression analysis of these genes in the presence of lindane revealed strong upregulation of one of the potential lin genes of Anabaena sp. PCC 7120.

Alterations of Systemic and Hepatic Metabolic Function Following Exposure to Trans-nonachlor in Low and High Fat Diet Fed Male Sprague Dawley Rats.

The overall prevalence of metabolic diseases such as type 2 diabetes (T2D) and associated co-morbidities have increased at an alarming rate in the United States and worldwide. There is a growing body of epidemiological evidence implicating exposure to persistent organic pollutants (POPs), including legacy organochlorine (OC) pesticides and their bioaccumulative metabolites, in the pathogenesis of metabolic diseases. Therefore, the goal of the present study was to determine if exposure to trans-nonachlor, a bioaccumulative OC pesticide contaminant, in concert with high fat diet intake induced metabolic dysfunction. Briefly, male Sprague Dawley rats were exposed to trans-nonachlor (.5 or 5 ppm) in either a low fat (LFD) or high fat diet (HFD) for 16 weeks. At 8 weeks of intake, trans-nonachlor decreased serum triglyceride levels in LFD and HFD fed animals and at 16 weeks compared to LFD fed animals. Interestingly, serum glucose levels were decreased by trans-nonachlor (5 ppm) in LFD fed animals at 16 weeks. Serum free fatty acids were increased by trans-nonachlor exposure (5 ppm) in LFD fed animals at 16 weeks. HFD fed animals displayed signs of hepatic steatosis including elevated liver triglycerides, liver enzymes, and liver lipid peroxidation which were not significantly altered by trans-nonachlor exposure. However, there was a trans-nonachlor mediated increase in expression of fatty acid synthase in livers of LFD fed animals and not HFD fed animals. Thus, the present data indicate exposure to trans-nonachlor in conjunction with LFD or HFD intake produces both diet and exposure dependent effects on lipid and glucose metabolism.

Identification and synergetic mechanism of TCE, H2 and O2 metabolic microorganisms in the joint H2/O2 system.

The sole H2 and O2 usually promote chlorinated hydrocarbons (CHCs) biotransformation by several mechanisms, including reductive dechlorination and aerobic oxidation. However, the mechanism of the CHCs transformation in joint H2 and O2 system (H2/O2 system) is still unclear. In this study, the degradation kinetics of trichloroethene (TCE) were investigated and DNA stable isotope probing (DNA-SIP) were used to explore the synergistic mechanism of functional microorganisms on TCE degradation under the condition of H2/O2 coexistence. In the H2/O2 microcosm, TCE was significantly removed by 13.00 µM within 40 days, much higher than N2, H2 and O2 microcosms, and 1,1-DCE was detected as an intermediate. DNA-SIP technology identified three anaerobic TCE metabolizers, five aerobic TCE metabolizers, nine hydrogen-oxidizing bacteria (HOB), some TCE metabolizers utilizing limited O2, and some anaerobic dechlorinating bacteria reductively using H2 to dechlorinate TCE. It is also confirmed for the first time that 3 OUTs belonging to Methyloversatilis and SH-PL14 can simultaneously utilize H2 and O2 as energy sources to grow and metabolize TCE or 1,1-DCE. HOB may provide carbon sources or electron acceptors or donors for TCE biotransformation. These findings confirm the coexistence of anaerobic and aerobic TCE metabolizers and degraders, which synergistically promoted the conversion of TCE in the joint H2/O2 system. Our results provide more information about the functional microbe resources and synergetic mechanisms for TCE degradation.

Viral and Bacterial Communities Collaborate through Complementary Assembly Processes in Soil to Survive Organochlorine Contamination.

The ecological drivers that direct the assembly of viral and host bacterial communities are largely unknown, even though viral-encoded accessory genes help host bacteria survive in polluted environments. To understand the ecological mechanism(s) of viruses and hosts synergistically surviving under organochlorine pesticide (OCP) stress, we investigated the community assembly processes of viruses and bacteria at the taxon and functional gene levels in clean and OCP-contaminated soils in China using a combination of metagenomics/viromics and bioinformatics approaches. We observed a decreased richness of bacterial taxa and functional genes but an increased richness of viral taxa and auxiliary metabolic genes (AMGs) in OCP-contaminated soils (from 0 to 2,617.6 mg · kg-1). In OCP-contaminated soils, the assembly of bacterial taxa and genes was dominated by a deterministic process, of which the relative significance was 93.0% and 88.7%, respectively. In contrast, the assembly of viral taxa and AMGs was driven by a stochastic process, which contributed 83.1% and 69.2%, respectively. The virus-host prediction analysis, which indicated Siphoviridae was linked to 75.0% of bacterial phyla, and the higher migration rate of viral taxa and AMGs in OCP-contaminated soil suggested that viruses show promise for the dissemination of functional genes among bacterial communities. Taken together, the results of this study indicated that the stochastic assembly processes of viral taxa and AMGs facilitated bacterial resistance to OCP stress in soils. Moreover, our findings provide a novel avenue for understanding the synergistic interactions between viruses and bacteria from the perspective of microbial ecology, highlighting the significance of viruses in mediating bioremediation of contaminated soils. IMPORTANCE The interaction between viral communities and microbial hosts has been studied extensively, and the viral community affects host community metabolic function through AMGs. Microbial community assembly is the process by which species colonize and interact to establish and maintain communities. This is the first study that aimed to understand the assembly process of bacterial and viral communities under OCP stress. The findings of this study provide information about microbial community responses to OCP stress and reveal the collaborative interactions between viral and bacterial communities to resist pollutant stress. Thereby, we highlight the importance of viruses in soil bioremediation from the perspective of community assembly.

Mycelial nutrient transfer promotes bacterial co-metabolic organochlorine pesticide degradation in nutrient-deprived environments.

Biotransformation of soil organochlorine pesticides (OCP) is often impeded by a lack of nutrients relevant for bacterial growth and/or co-metabolic OCP biotransformation. By providing space-filling mycelia, fungi promote contaminant biodegradation by facilitating bacterial dispersal and the mobilization and release of nutrients in the mycosphere. We here tested whether mycelial nutrient transfer from nutrient-rich to nutrient-deprived areas facilitates bacterial OCP degradation in a nutrient-deficient habitat. The legacy pesticide hexachlorocyclohexane (HCH), a non-HCH-degrading fungus (Fusarium equiseti K3), and a co-metabolically HCH-degrading bacterium (Sphingobium sp. S8) isolated from the same HCH-contaminated soil were used in spatially structured model ecosystems. Using 13C-labeled fungal biomass and protein-based stable isotope probing (protein-SIP), we traced the incorporation of 13C fungal metabolites into bacterial proteins while simultaneously determining the biotransformation of the HCH isomers. The relative isotope abundance (RIA, 7.1-14.2%), labeling ratio (LR, 0.13-0.35), and the shape of isotopic mass distribution profiles of bacterial peptides indicated the transfer of 13C-labeled fungal metabolites into bacterial proteins. Distinct 13C incorporation into the haloalkane dehalogenase (linB) and 2,5-dichloro-2,5-cyclohexadiene-1,4-diol dehydrogenase (LinC), as key enzymes in metabolic HCH degradation, underpin the role of mycelial nutrient transport and fungal-bacterial interactions for co-metabolic bacterial HCH degradation in heterogeneous habitats. Nutrient uptake from mycelia increased HCH removal by twofold as compared to bacterial monocultures. Fungal-bacterial interactions hence may play an important role in the co-metabolic biotransformation of OCP or recalcitrant micropollutants (MPs).

Organochlorine pesticides induce epithelial as well as inflammatory mediators following exposure to human ovarian surface epithelial cells: An in vitro study.

Although studies have suggested organochlorine pesticides (OCPs) exposure increased the risk of epithelial ovarian cancer, the mechanisms underlying its potential tumorigenic effects in the human ovary are not well understood. In this study, we investigated the impact of dichlorodiphenyldichloroethylene (DDE), endosulfan, and heptachlor exposure on epithelial cadherin (E-cadherin) and proinflammatory mediators in human ovary surface epithelial (HOSE) cells. We found that DDE, endosulfan, and heptachlor exposure resulted in epithelial differentiation accompanied by upregulation of E-cadherin expression and overexpression of proinflammatory cytokines (TNFα, IL-1ß, and IL-6) in HOSE cells. The epithelial differentiation may accelerate HOSE cells to inclusion body formation, a common site for ovarian cancer initiation and persistent exposure to OCPs creates a chronic inflammatory microenvironment that may promote the neoplastic transformation of HOSE cells within the inclusion cyst.

Effect of Affinity between Dechlorane Plus and Human Serum Albumin on Its Serum Concentration in a General Population.

Dechlorane Plus (DP) has been detected in human serum around the world. Determining how DP binds to human serum albumin (HSA) could improve our understanding of the effects of DP in humans. The results of a fluorescence titration experiment indicated that DP binds to HSA at the interface between domains IIA and IIB, and HSA has more affinity for anti-DP than syn-DP. The DP concentrations in serum from 33 people living in Wuxi City, China, were determined in five consecutive years (2012-2016). The total concentrations of the two DP isomers were 1.73-16.3 ng·g-1 lipid weight (mean 4.7 ng·g-1 lipid weight). No clear increasing or decreasing temporal trend was found in the DP concentrations in serum over the study period. The affinity between DP and HSA will increase as the amount of fatty acids combined with HSA increases. This explained the syn-DP and anti-DP concentrations in serum being higher for overweight people than for normal weight people. Ethanol can occupy the DP binding sites on HSA. This explained the syn-DP and anti-DP concentrations being lower for alcoholic people than for nonalcoholic people.

Halogenated polycyclic aromatic hydrocarbons in edible aquatic species of two Asian countries: Congener profiles, biomagnification, and human risk assessment.

Seventy-five contaminants including chlorinated/brominated/parent polycyclic aromatic hydrocarbons (Cl/Br/PAHs) were investigated in 29 edible aquatic species from the Indian Ocean near Sri Lanka and 10 species from the Pacific Ocean near Japan. Concentrations of total ClPAHs and BrPAHs in the samples were 2.6-57 and 0.30-9.5 ng/g-dry weight from the Indian Ocean, and 0.35-18 and 0.03-3.3 ng/g-dry weight from the Pacific Ocean, respectively. Comparing the profiles of Cl/BrPAHs among the samples, congeners of chlorinated and brominated pyrene were predominant components and enhanced the potential for biomagnification in the sample from the off-shore pelagic environment in the Indian Ocean. The incremental lifetime cancer risks estimated by intake of the targets in consuming aquatic organisms showed that approximately one-third of studied organisms exceeded the acceptable risk level for Sri Lankans.

Adipose Tissue Redox Microenvironment as a Potential Link between Persistent Organic Pollutants and the 16-Year Incidence of Non-hormone-Dependent Cancer.

We aimed to assess the relationships among the adipose tissue's (AT) oxidative microenvironment, in situ accumulated persistent organic pollutant (POP) concentrations, and cancer development. POP and oxidative stress levels were quantified in AT samples from 382 adults recruited within the GraMo cohort (2003-2004) in Granada (Spain). The 16-year cancer incidence was ascertained by reviewing health/administrative databases. Cox-regression models and mediation analyses were performed. The enzymes superoxide dismutase (SOD) and glutathione reductase (GRd) were positively associated with the risk of non-hormone-dependent (NHD) cancer [adjusted hazard ratio (HR) 1.76; 95% confidence interval (CI): 1.17, 2.64 and HR 2.35; 95% CI: 1.41, 3.94, respectively]. After adjustment for covariates, polychlorinated biphenyl-138 (PCB-138) (HR 1.78; 95% CI: 1.03, 3.09), ß-hexachlorocyclohexane (ß-HCH) (HR 1.70; 95% CI: 1.09, 2.64), and hexachlorobenzene (HR 1.54; 95% CI: 1.02, 2.33) were also positively associated with the risk of NHD cancer. Although confidence intervals included the null value, probably because of the modest number of cancer cases, we observed a potential mediation effect of SOD and GRd on the associations between ß-HCH and the risk of NHD tumors (percent mediated = 33 and 47%, respectively). Our results highlight the relevance of human AT's oxidative microenvironment as a predictor of future cancer risk as well as its potential mediating role on POP-related carcinogenesis. Given their novelty, these findings should be interpreted with caution and confirmed in future studies.

Organochlorine Pesticide Tissue Levels in Benign and Malignant Breast Disease: A Comparative Exploratory Study.

Exposure to organochlorine pesticides (OCPs) may be a risk factor for breast cancer (BC). Their role may be more relevant in developing countries such as India, where an abundance of these products is used for agricultural purposes. The present study compares OCP tissue levels in patients who underwent BC surgery (group A) or patients who had surgery for excision of breast fibroadenoma (group B). We perform OCP level quantification using a PerkinElmer, Inc. (Waltham, MA) gas chromatograph (GC) that is equipped with a 63Ni selective electron-capture detector. Significantly higher breast tissue OCP levels are present in the study population, indicating significant exposure. We detect 18 different types of OPCs in study subjects, with six OPCs (γ-hexachlorocyclohexane [HCH], δ-HCH, endrin, endosulfan-II, p,p'-dichlorodiphenyldichloroenthane [DDD], and p,p'-dichlorodiphenyltrichloroenthane [DDT]) present in all subjects. Endosulfan-II, p,p'-DDT, and p,p'-DDD tissue levels are significantly higher in BC patients than in those with fibroadenoma. Higher tissue levels of OCPs (α-HCH) are significantly associated with the presence of extracapsular spread (1.42 vs. 0.91; p = 0.04) and higher disease stage (early BC vs. locally advanced BC; 18.90 vs. 11.90; p = 0.04). The present pilot study indicates higher OCP tissue levels in northern India BC patients compared to patients with fibroadenoma.

Acetylene-Fueled Trichloroethene Reductive Dechlorination in a Groundwater Enrichment Culture.

In aquifers, acetylene (C2H2) is a product of abiotic degradation of trichloroethene (TCE) catalyzed by in situ minerals. C2H2 can, in turn, inhibit multiple microbial processes including TCE dechlorination and metabolisms that commonly support dechlorination, in addition to supporting the growth of acetylenotrophic microorganisms. Previously, C2H2 was shown to support TCE reductive dechlorination in synthetic, laboratory-constructed cocultures containing the acetylenotroph Pelobacter sp. strain SFB93 and Dehalococcoides mccartyi strain 195 or strain BAV1. In this study, we demonstrate TCE and perchloroethene (PCE) reductive dechlorination by a microbial community enriched from contaminated groundwater and amended with C2H2 as the sole electron donor and organic carbon source. The metagenome of the stable, enriched community was analyzed to elucidate putative community functions. A novel anaerobic acetylenotroph in the phylum Actinobacteria was identified using metagenomic analysis. These results demonstrate that the coupling of acetylenotrophy and reductive dechlorination can occur in the environment with native bacteria and broaden our understanding of biotransformation at contaminated sites containing both TCE and C2H2IMPORTANCE Understanding the complex metabolisms of microbial communities in contaminated groundwaters is a challenge. PCE and TCE are among the most common groundwater contaminants in the United States that, when exposed to certain minerals, exhibit a unique abiotic degradation pathway in which C2H2 is a product. C2H2 can act as both an inhibitor of TCE dechlorination and of supporting metabolisms and an energy source for acetylenotrophic bacteria. Here, we combine laboratory microcosm studies with computational approaches to enrich and characterize an environmental microbial community that couples two uncommon metabolisms, demonstrating unique metabolic interactions only yet reported in synthetic, laboratory-constructed settings. Using this comprehensive approach, we have identified the first reported anaerobic acetylenotroph in the phylum Actinobacteria, demonstrating the yet-undescribed diversity of this metabolism that is widely considered to be uncommon.

Occurrence of Organochlorine Pesticides in Human Tissues Assessed Using a Microextraction Procedure and Gas Chromatography-Mass Spectrometry.

This work focuses on the development, validation and application of an analytical method for the determination of twenty organochlorine pesticides (OCPs) in human tissues using salting-out liquid-liquid extraction and dispersive liquid-liquid microextraction for sample preparation and gas chromatography-mass spectrometry to analyze the obtained extracts. Measurement of the concentration levels of these toxics in tissues can be used to assess the risk of the population to exposure. The linearity of the proposed method was verified in the 10-1,000 ng/g range. The sensitivity was evaluated calculating the limits of detection (LODs) for 20 OCPs (α-, ß-, γ- and δ-hexachlorocyclohexane (HCH), α- and ß-endosulfan, endosulfan sulfate, aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde, α- and γ-chlordane, 4,4'-dichlorodiphenyltrichloroethane, 4,4'-dichlorodiphenyldichloroethylene (DDE), 4,4'-dichlorodiphenyldichloroethane, heptachlor, heptachlor epoxide and methoxychlor), most of them being found between 1.0 and 16 ng/g. The intra- and interday precisions were <12% for relative standard deviation values. The accuracy of the method was evaluated by recovery studies, which gave recovery percentages in the 85-109% range. Seven different tissues (liver, kidney, heart, spleen, lung, brain and abdominal fat) from eight autopsies were analyzed, and only three cases were seen to have ß-HCH and 4,4'-DDE in abdominal fat, while 4,4'-DDE was also detected in the heart of one case. The rest of the samples were free of the studied OCPs at least above the corresponding LODs.

Organochlorines burden in moss H. cupressiforme and topsoil across Serbia.

Following up-to-date initiatives of the Stockholm Convention, its global monitoring plan, and the International Cooperative Programme on Natural Vegetation and Crops (ICP Vegetation 2015) under the convention on long-range transboundary air pollution, this study examined 17 polychlorinated biphenyls (PCBs) and seven organochlorine pesticides (OCPs) in the moss Hypnum cupressiforme Hedw. and topsoil sampled across Serbia. In the topsoil, OCPs ranged from 0.0158 to 9.6804 ng g-1 while concentrations of individual PCB congeners were in the range between 0.0185 and 0.3107 ng g-1. The levels of OCPs and PCBs in the moss H. cupressiforme ranged from 2.7785 to 23.9501 ng g-1, and from 0.4325 to 15.8013 ng g-1, respectively. POP relationships between topsoil and moss investigated by fugacity model equations indicated that the moss POP enrichment was a result of atmospheric long-range transport rather than secondary reemissions from soil.

Protein Proximity Observed Using Fluorogen Activating Protein and Dye Activated by Proximal Anchoring (FAP-DAPA) System.

The development and function of tissues, blood, and the immune system is dependent upon proximity for cellular recognition and communication. However, the detection of cell-to-cell contacts is limited due to a lack of reversible, quantitative probes that can function at these dynamic sites of irregular geometry. Described here is a novel chemo-genetic tool developed for fluorescent detection of protein-protein proximity and cell apposition that utilizes the Fluorogen Activating Protein (FAP) in combination with a Dye Activated by Proximal Anchoring (DAPA). The FAP-DAPA system has two protein components, the HaloTag and FAP, expressed on separate protein targets or in separate cells. The proteins function to bind and activate a compound that has the hexyl chloride (HexCl) ligand connected to malachite green (MG), the FAP fluorogen, via a poly(ethylene glycol) spacer spanning up to 28 nm. The dehalogenase protein, HaloTag, covalently binds the HexCl ligand, locally concentrating the attached MG. If the FAP is within range of the anchored fluorogen, it will bind and activate MG specifically when the bath concentration is too low to saturate the FAP receptor. A new FAP variant was isolated with a 1000-fold reduced KD of ∼10-100 nM so that the fluorogen activation reports proximity without artificially enhancing it. The system was characterized using purified FRB and FKBP fusion proteins and showed a doubling of fluorescence upon rapamycin induced complex formation. In cocultured HEK293 cells (HaloTag and FAP-expressing) fluorescence increased at contact sites across a broad range of labeling conditions, more reliably providing contact-specific fluorescence activation with the lower-affinity FAP variant. When combined with suitable targeting and expression constructs, this labeling system may offer significant improvements in on-demand detection of intercellular contacts, potentially applicable in neurological and immunological synapse measurements and other transient, dynamic biological appositions that can be perturbed using other labeling methods that stabilize these interactions.

Short- and Medium-Chain Chlorinated Paraffins in Foods from the Sixth Chinese Total Diet Study: Occurrences and Estimates of Dietary Intakes in South China.

Food consumption has been identified as a major pathway for human exposure to short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs), but evaluations of SCCP and MCCP intake from major dietary sources are limited. We used the sixth Chinese Total Diet Study to perform a comprehensive investigation of SCCPs and MCCPs in cereals, vegetables, potatoes, legumes, eggs, milk, meats, and aquatic foods from nine southern provinces. The geographical distribution of CP concentrations showed higher levels in Jiangsu, Hubei, and Zhejiang provinces. The CP concentrations in most animal-origin foods were higher than those in foods of plant origin. The total estimated daily intakes (EDIs) of SCCPs and MCCPs, with average values of 7.0 × 102 and 4.7 × 102 ng kg-1 day-1, respectively, were mostly contributed by cereals, vegetables, and meats. Risk assessment indicated the EDIs of CPs posed no significant risk to residents in South China.

Bioremediation of typical chlorinated hydrocarbons by microbial reductive dechlorination and its key players: A review.

Chlorinated hydrocarbon contamination in soils and groundwater has a severe negative impact on the human health. Microbial reductive dechlorination is a major degradation pathway of chlorinated hydrocarbon in anaerobic subsurface environments, has been extensively studied. Recent progress on the diversity of the reductive dechlorinators and the key enzymes of chlororespiration has been well reviewed. Here, we present a thorough overview of the studies related to bioremediation of chloroethenes and polychlorinated biphenyls based on enhanced in situ reductive dechlorination. The major part of this review is to provide an up-to-date summary of functional microorganisms which are either detected during in situ biostimulation or applied in bioaugmentation strategies. The applied biostimulants and corresponding reductive dechlorination products are also summarized and the future research needs are finally discussed.

[Advances in microbial degradation of chlorinated hydrocarbons].

Chlorinated hydrocarbons (CAHs) threaten human health and the ecological environment due to their strong carcinogenic, teratogenic, mutagenic and heritable properties. Heterotrophic assimilation degradation can completely and effectively degrade CAHs, without secondary pollution. However, it is crucial to comprehensively understand the heterotrophic assimilation process of CAHs for its application. Therefore, we review here the characteristics and advantages of heterotrophic assimilation degradation of CAHs. Moreover, we systematically summarize current research status of heterotrophic assimilation of CAHs. Furthermore, we analyze bacterial genera and metabolism, key enzymes and characteristic genes involved in the metabolic process. Finally, we indicate existing problems of heterotrophic assimilation research and future research needs.

Bioaccumulation of persistent organic pollutants in the gonads of Barbus barbus (Linnaeus, 1758).

Maps with grey or even white spaces are still present in spite of the fact that persistent organic pollutants (POPs) are at the forefront of research in aquatic toxicology and environmental safety. This is also the case for the Mureș River basin. The intensive use of industrial substances such as polychlorinated biphenyls (PCBs) and pesticides such as organochlorine compounds (OCPs) has caused global contamination of the aquatic environment. In our study we have found very high concentrations of both PCBs (2110-169,000 ng/g lipid weight ΣPCB, 1950-166,000 ng/g lipid weight ΣPCB7) and OCPs (1130-7830 ng/g lipid weight ΣDDT, 47.6-2790 ng/g lipid weight ΣHCH, 5.53-35.6 ng/g lipid weight ΣChlordane, and 6.74-158 ng/g lipid weight HCB) in the gonad tissue of Barbus barbus (Linnaeus, 1758) males and females. Contrary to most studies where the weight, length, and lipid percentage are positively correlated with the concentration of POPs from different tissue types, we observed a downward trend for the lipid normalized concentrations of some pollutants in gonads while these indices were actually increasing. The decrease of lipid normalized POPs with the increase of CF and lipid percentage may be due to the fact that individuals are eliminating hard and soft roes every year during reproduction which could mean that some quantities of pollutants are also eliminated along with the hard and soft roes. The high POPs concentrations found in our study should be a needed wakeup call for environmentalists and a starting point in developing monitoring and management measures for these pollutants.