Tissue-Specific Distribution and Maternal Transfer of Persistent Organic Halogenated Pollutants in Frogs.

Persistent organic pollutants pose a great threat to amphibian populations, but information on the bioaccumulation of contaminants in amphibians remains scarce. To examine the tissue distribution and maternal transfer of organic halogenated pollutants (OHPs) in frogs, seven types of tissues from black-spotted frog (muscle, liver, kidney, stomach, intestine, heart, and egg) were collected from an e-waste-polluted area in South China. Among the seven frog tissues, median total OHP concentrations of 2.3 to 9.7 µg/g lipid weight were found (in 31 polychlorinated biphenyl [PCB] individuals and 15 polybrominated diphenyl ether [PBDE], dechlorane plus [syn-DP and anti-DP], bexabromobenzene [HBB], polybrominated biphenyl] PBB153 and -209], and decabromodiphenyl ethane [DBDPE] individuals). Sex-specific differences in contaminant concentration and compound compositions were observed among the frog tissues, and eggs had a significantly higher contaminant burden on the whole body of female frogs. In addition, a significant sex difference in the concentration ratios of other tissues to the liver was observed in most tissues except for muscle. These results suggest that egg production may involve the mobilization of other maternal tissues besides muscle, which resulted in the sex-specific distribution. Different parental tissues had similar maternal transfer mechanisms; factors other than lipophilicity (e.g., molecular size and proteinophilic characteristics) could influence the maternal transfer of OHPs in frogs. Environ Toxicol Chem 2024;00:1-12. © 2024 SETAC.

Tetrabromobisphenol-A/S and their derivatives in surface particulates from workshop floors of three representative e-waste recycling sites in China.

Surface particulates collected from the workshop floors of three major e-waste recycling sites (Taizhou, Qingyuan, and Guiyu) in China were analyzed for tetrabromobisphenol A/S (TBBPA/S) and their derivatives to investigate the environmental pollution caused by e-waste recycling activities. Mean concentrations of total TBBPA/S analogs in surface particulates were 31,471-116,059 ng/g dry weight (dw). TBBPA, TBBPA-BGE, and TBBPA-BDBPE were the most frequently detected in particulates with average concentration ranges of 17,929-78,406, 5601-15,842, and 5929-21,383 ng/g dw, respectively. Meanwhile, TBBPA, TBBPA-BGE, and TBBPA-BDBPE were the most abundant TBBPA/S analogs, accounting for around 96% of the total. The composition profiles of TBBPA/S analogs differed significantly among three e-waste sites. Similarly, principal component analysis uncovered different pollution patterns among different sites. The discrepancy in the profiles of TBBPA/S analogs largely relied on the e-waste types recycled in different areas. E-waste recycling led to the release of TBBPA/S analogs, and TBBPA/S analogs produced differentiation during migration from source (surface particulates) to nearby soil. More researches are necessary to find a definite relationship between pollution status and e-waste types and study differentiation behavior of TBBPA/S analogs in migration and diffusion from source to environmental medium.

Comprehensive characterization and prioritization of halogenated organic compounds in fish and their implications for exposure.

Fish are an important pollution indicator for biomonitoring of halogenated organic compounds (HOCs) in aquatic environments, and HOCs in fish may pose health threats to consumers. This study performed nontarget and comprehensive analyses of HOCs in fish from an e-waste recycling zone by gas chromatography-high-resolution mass spectrometry, and further prioritized their human exposure risks. A total of 1652 formulas of HOCs were found in the fish, of which 1222, 117, and 313 were organochlorines, organobromines, and organochlorine-bromines, respectively. The total concentrations of HOCs were 15.4-18.7 µg/g (wet weight), and organobromines were the predominant (14.1-16.8 µg/g). Of the HOCs, 41 % were elucidated with tentative structures and divided into 13 groups. The estimated total daily exposures of HOCs via dietary consumption of the fish for local adult residents were 3082-3744 ng/kg bw/day. The total exposures were dominated by several groups of HOCs with the following contribution order: polyhalogenated biphenyls and their derivatives > polyhalogenated diphenyl ethers > halo- (H-)alkanes/olefines > H-benzenes > H-dioxins > H-polycyclic aromatic hydrocarbons > H-phenols. The comprehensive characterization and prioritization results provide an overview of the species and distributions of HOCs in edible fish, and propose an inventory of crucial HOCs associated with high exposure risks.

A comprehensive assessment of external exposure to persistent halogenated organic pollutants for residents in an e-waste recycling site, South China.

Human skin wipes from 30 participants, air, dust, and food items were collected from a former electronic waste site in South China to provide a comprehensive understanding of residents' exposure to halogenated flame retardants (HFRs) and polychlorinated biphenyls (PCBs). The total concentration of halogenated organic pollutants (HOPs) in the dust, air, food and skin wipes ranged 240-25000 ng/g, 130-2500 pg/m3, 0.08-590 ng/g wet weight, and 69-28000 ng/m2, respectively. Wild fish, vegetables, and air were dominated by PCBs, whereas dust, livestock, and poultry were dominated by HFRs. The HOP concentrations were several orders of magnitude higher in local foodstuffs than in market foodstuffs. The chemical composition on the forehead was remarkably different from that on the hand. The importance of different exposure routes depends on the residents' food choices, except decabromodiphenyl ethane (DBDPE). For residents who consumed a 100-foot diet (mainly egg) and local wild fish, diet ingestion overwhelmed other exposure routes, and PCBs were mainly contributed by fish and HFRs by egg. For residents who consumed market food, the dermal absorption of most PCB congeners and dust ingestion of highly brominated flame retardants were relatively prominent. Inhalation was found to be a crucial route for pentabromoethylbenzene (PBEB).

Multi-pathway exposure assessment of organophosphate flame retardants in a southern Chinese population: Main route identification with compound-specificity.

In this study, we conducted comprehensive organophosphorus flame retardant (PFR) exposure assessments of both dietary and non-dietary pathways in a rural population in southern China. Skin wipes were collected from 30 volunteers. Indoor and outdoor air (gas and particles), dust in the houses of these volunteers, and foodstuffs consumed by these volunteers were simultaneously collected. The total PFR concentrations in dust, gas, and PM2.5 varied from 53.8 to 5.14 × 105 ng/g, 0.528 to 4.27 ng/m3, and 0.390 to 16.5 ng/m3, respectively. The forehead (median of 1.36 × 103 ng/m2) and hand (median of 920 ng/m2) exhibited relatively high PFR concentrations, followed by the forearm (median of 440 ng/m2) and upper arm (median of 230 ng/m2). The PFR concentrations in the food samples varied from 0.0700 to 10.9 ng/g wet weight in the order of egg > roast duck/goose and vegetable > pork > chicken > fish. Tris(1-chloro-isopropyl) phosphate (TCPP) was the main PFR in the non-diet samples, whereas the profiles of PFR individuals varied by food type. Among the multiple pathways investigated (inhalation, dermal exposure, dust ingestion, and food ingestion), dermal absorption and dust ingestion were the predominant pathways for tris(2-chloroethyl) phosphate (TCEP) and bisphenol A-bis(diphenyl phosphate) (BDP), respectively, whereas dietary exposure was the most important route for other chemicals.

Nontarget Analysis and Comprehensive Characterization of Iodinated Polyfluoroalkyl Acids in Wastewater and River Water by LC-HRMS with Cascade Precursor-Ion Exclusions and Algorithmic Approach.

Poly- and perfluoroalkyl acids (PFAAs) are a large family of widespread contaminants of worldwide concern and well-known as "forever chemicals". Direct emission of PFAAs from the fluorochemical industry is a crucial source of PFAA pollutants in the environment. This study implemented nontarget analysis and comprehensive characterization for a category of new PFAA contaminants, i.e., iodinated PFAAs (IPFAAs), in fluorochemical industry wastewater and relevant contaminated river water by liquid chromatography-high-resolution mass spectrometry with a cascade precursor ion exclusion (PIE) strategy and in-house developed data extraction and processing algorithms. A total of 26 IPFAAs (including 2 isomers of an IPFAA) were found and identified with tentative molecular structures. Semiquantification of the IPFAAs was implemented, and the total concentrations of IPFAAs were 0.16-285.52 and 0.15-0.17 µg/L in wastewater and river water, respectively. The high concentrations in association with the predicted ecotoxicities and environmental behaviors demonstrate that these IPFAAs are worthy of more concern and further in-depth research. The cascade PIE strategy along with the data extraction and processing algorithms can be extended to nontarget analysis for other pollutants beyond IPFAAs. The nontarget identification and characterization outcomes provide new understanding on the environmental occurrence and pollution status of IPFAAs from a comprehensive perspective.

Trophic Transfer of Halogenated Organic Pollutants in a Wetland Food Web: Insights from Compound-Specific Nitrogen Isotope of Amino Acids and Food Source Analysis.

A trophic position (TP) model (TPmix model) that simultaneously considered trophic discrimination factor and ßGlu/Phe variations was developed in this study and was first applied to investigate the trophic transfer of halogenated organic pollutants (HOPs) in wetland food webs. The TPmix model characterized the structure of the wetland food web more accurately and significantly improved the reliability of TMF compared to the TPbulk, TPAAs, and TPsimmr models, which were calculated based on the methods of stable nitrogen isotope analysis of bulk, traditional AAs-N-CSIA, and weighted ßGlu/Phe, respectively. Food source analysis revealed three interlocking food webs (kingfisher, crab, and frogs) in this wetland. The highest HOP biomagnification capacities (TMFmix) were found in the kingfisher food web (0.24-82.0), followed by the frog (0.08-34.0) and crab (0.56-11.7) food webs. The parabolic trends of TMFmix across combinations of log KOW in the frog food web were distinct from those of aquatic food webs (kingfisher and crab), which may be related to differences in food web composition and HOP bioaccumulation behaviors between aquatic and terrestrial organisms. This study provides a new tool to accurately study the trophic transfer of contaminants in wetlands and terrestrial food webs with diverse species and complex feeding relationships.

Bioaccumulation, tissue distributions, and maternal transfer of perfluoroalkyl carboxylates (PFCAs) in laying hens.

Laying hens were exposed to feeds spiked with a series of perfluoroalkyl carboxylates (PFCAs) ranging from perfluorobutanoic acid (C4) to perfluorooctadecanoic acid (C18) to investigate their bioaccumulation, tissue distribution, and maternal transfer. We found that PFCAs with longer carbon chains (>8) were more efficiently absorbed in the gastrointestinal tract than those with shorter chains (≤8), and that the rate of depuration varied inversely with the carbon chain length in a U-shaped pattern. Moreover, bioaccumulation potential increased with increasing carbon-chain length, except for C4. Distinct affinities were observed for specific carbon-chain PFCAs across various tissues, evident from their differential accumulation during both uptake and depuration phases. Specifically, C9 showed a higher affinity for serum and liver, C12 was more prevalent in yolk, C14 was notably abundant in the brain, and C18 was predominant in other tissues. Furthermore, the egg-maternal ratio (EMR) increased with increasing carbon-chain length from C7 to C11 and reached a plateau phase for C12 to C18. Our study also confirmed the key role of phospholipids in the tissue distribution and maternal transfer of long-chain PFCAs. This study sheds light on the interaction between PFCAs and biological tissues and reveals the toxicokinetic factors that influence the bioaccumulation of PFCAs. Further research is needed to identify the specific proteins or components that mediate the tissue-specific affinity for different carbon-chain lengths of PFCAs.

Nontarget and Comprehensive Analyses of Halogenated Organic Additives in Electrical Product Plastics by GC-NCI-Q-Orbitrap-HRMS and Cl/Br-Screening Algorithms.

Halogenated organic additives (HOAs) are used in plastic components of various electrical products, potentially causing detrimental effects on the eco-environment and humans. Besides reported HOAs, many unknown HOAs may be present in electrical product plastics and urgently require identification and characterization. This study performed nontarget analysis and comprehensive characterization of HOAs in three typical electrical product plastics by nontarget analysis using gas chromatography-negative chemical ionization-high-resolution mass spectrometry in association with in-house-developed chlorine/bromine-specific data-processing algorithms. A total of 674 formulas of HOAs were identified in the plastics dismantled from three electrical products, among which 166, 362, and 146 were organochlorines, organobromines, and mix-chlorinated/brominated organic compounds, respectively. The identified HOAs were semiquantified, and the total concentrations of HOAs in individual plastics were 445-1549 ng/g. Organobromines showed the most species and the highest abundances in all of the plastics, of which the abundances accounted for 86.6-98.0% of the total HOAs. Partial HOAs (209 formulas) were tentatively structurally elucidated, which were classified into 13 groups, i.e., halogenated alkyl phenoxyethyls (H-alkyl phenoxyethyls), H-alkylbenzenes, H-benzenes, H-bisphenol A (H-BPAs), H-dioxins, H-diphenyl ethers, H-biphenyls/terphenyls, H-polycyclic aromatic hydrocarbons, H-phenols, H-phenyl esters, H-phenyl-aldehydes/ketones, H-quinones, and an undefined group containing the HOAs such as dechlorane plus and chlordane. H-BPAs were the predominant HOAs in the plastics, showing relatively high concentrations (13-281 ng/g), and tetrabromobisphenol A was the most abundant H-BPA, with the concentrations of 9-196 ng/g. The comprehensive characterization results represent a holistic picture on the species features and abundance distributions of HOAs in electrical product plastics and provide an inventory of crucial HOAs worthy of concern. HOAs may migrate from plastics and release into the environment and are possibly an important source of halogenated organic pollutants in the environment, thus calling for further investigation and proper regulation.

Sex-Specific Bioaccumulation, Maternal Transfer, and Tissue Distribution of Legacy and Emerging Per- and Polyfluoroalkyl Substances in Snakes (Enhydris chinensis) and the Impact of Pregnancy.

The effects of sex and pregnancy on the bioaccumulation and tissue distribution of legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Chinese water snakes were investigated. The bioaccumulation factor of PFASs showed a positive correlation with their protein-water partition coefficients (log KPW), and steric hindrance effects were observed when the molecular volume was > 357 Å3. PFAS levels in females were significantly lower than those in males. The chemical composition of pregnant females was significantly different from that of non-pregnant females and males. The maternal transfer efficiencies of perfluorooctane sulfonic acid were higher than those of other PFASs, and a positive correlation between the maternal transfer potential and log KPW was observed for other PFASs. Tissues with high phospholipid content exhibited higher concentrations of ∑PFASs. Numerous physiological changes occurred in maternal organ systems during pregnancy, leading to the re-distribution of chemicals among different tissues. The change in tissue distribution of PFASs that are easily and not-so-easily maternally transferred was in the opposite direction. The extent of compound transfer from the liver to the egg determined tissue re-distribution during pregnancy.

First Discovery of Iodinated Polyfluoroalkyl Acids by Nontarget Mass-Spectrometric Analysis and Iodine-Specific Screening Algorithm.

Per- and polyfluoroalkyl acids (PFAAs) including polyfluoroalkyl carboxylic acids and polyfluoroalkyl sulfonic acids are a large category of crucial environmental pollutants of global concern. Besides known PFAAs, numerous unknown species may exist in the environment, urgently needing discovery and characterization. This study implemented nontarget analysis for a group of novel PFAA pollutants, viz., iodinated PFAAs (I-PFAAs) in wastewater from a fluorochemical manufacturing park by liquid chromatography-high-resolution mass spectrometry in combination with an iodine-specific data-processing algorithm. The algorithm took into account the diagnostic fragment iodine ion (I-) together with carbon and sulfur isotopologue distributions. In total, 18 I-PFAA formulas involving 21 congeners were identified. Semiquantification was conducted, and the total concentrations of I-PFAAs were 1.9-274.7 µg/L, indicating severe pollution of I-PFAAs in the wastewater. The determined concentrations along with predicted environmental behaviors and toxicities demonstrate that I-PFAAs merit further in-depth investigation. The analytical method including the instrumental analysis and data-processing algorithm can be extended to screening and identification of I-PFAAs in other matrices. Furthermore, the analysis results for the first time provide recognition on the occurrence, distribution features, and pollution status of I-PFAAs in the environment.

A new insight into the emission source of DDT in indoor environment from rural area of South China and comprehensive human health exposure assessment.

Human exposure to dichlorodiphenyltrichloroethanes (DDTs) and the subsequent risk to human health remain an important concern due to the "new" input of DDTs in the environment, especially since exposure to DDTs in indoor microenvironments is often ignored. In this study, we identified a new source of DDT emission in indoor environments and evaluated the health risk from the exposure to DDTs by investigating DDTs in indoor and outdoor dust, air, and coatings of household items in rural areas of Qingyuan, South China. The concentrations of DDTs in house dust and air were < MQL (method quantification limit)-3450 ng/g (median 42.4 ng/g) and 22.7-965 pg/m3 (median 49.5 pg/m3), respectively, which were significantly higher than the outdoor DDT values. Dichlorodiphenyldichloroethylene (DDE) was the main isomer in air samples, while DDT was the dominant isomer in indoor dust. Significant correlations between different DDT isomers were observed in indoor samples but not in outdoor samples. Furniture coating was identified as a source of DDTs in the indoor dust. The total daily exposure dose of DDTs (1.75 × 10-2 ng/kg bw/day for adults and 1.28 × 10-1 ng/kg bw/day for toddlers) through inhalation, dust ingestion, and dermal contact was found unlikely to pose a health risk. Our findings provide new insights into the emission sources and health risks caused by DDT indoors, highlighting the need to further investigate the toxicity mechanisms of parent DDT compound.

Occurrence, spatial distribution, and risk assessment of short- and medium-chain chlorinated paraffins in sediment from black-odorous rivers across China.

Chlorinated paraffins (CPs) were massively produced for varied industrial purposes, of which improper handling and consequent environmental release resulted in worldwide contamination. The present study investigated the occurrence and spatial distribution of short- and medium-chain chlorinated paraffins (SCCP/MCCPs) in 171 sediment samples from black-odorous urban rivers across China. Total SCCP and MCCP concentrations ranged from 8.3 to 9.4 × 104 (median: 1.1 × 103) ng/g dw, and from not-detected-value to 1.0 × 106 (median: 1.3 × 104) ng/g dw, respectively. No clear spatial distribution of SCCPs and MCCPs was observed since black-odorous urban rivers were polluted by point-sources of the SCCP/MCCPs. Significant positive correlations were identified between SCCP/MCCPs and total organic carbon, and between SCCP/MCCPs and other persistent organic matter, including polybrominated diethyl ethers, polychlorinated biphenyls, antibiotics, and plasticizers. The average ratios of MCCPs to SCCPs in most samples were divided into 11 and 16, implying the manufacturing and use of at least two types of CP technical mixtures in China. The composition of SCCP/MCCPs were similar to that in their commercial products. Ecological risk assessments by two approaches, including the Federal Environmental Quality Guidelines and Risk Quotient, both revealed that SCCP/MCCP in surface sediments confer an ecological risk. ENVIRONMENTAL IMPLICATION: SCCPs and MCCPs can be considered "hazardous materials" because of their massive production and their potential persistence, long-distance transfer, bioaccumulation potential, and toxicity. This research conducted a comprehensive study on SCCP/MCCP in black-odorous urban river sediments across China and revealed their environmental risk, which may improve understanding of SCCP/MCCP contamination characteristics.

Bioamplification and Biomagnification of Polycyclic Aromatic Hydrocarbons and Halogenated Organic Pollutants in Moths from an Electronic Waste Recycling Site.

Samples of Asota caricae (larvae, pupae, and adults) and its host plant leaf (Ficus hispida), larvae of Aloa lactinea, and mixed adult moths were collected from an electronic waste (e-waste) recycling site in south China. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers were found to exhibit concentrations of 420-1300, 100-860, and 7.6-49 ng/g dry weight, respectively. The different chemical compositions among the samples of the three groups indicated that at least two exposure scenarios occurred among the moths in the study area. A complex relationship between bioamplification factors and the octanol-water partition coefficient (log KOW ) was observed during metamorphosis, in which a positive relationship was evident for 5 < log KOW < 7, whereas an inverse relationship occurred for log KOW values outside of this range. The biomagnification factors (BMFs) calculated from the larvae of Asota caricae to the host plant were negatively correlated with log KOW for all chemicals, differing completely from those obtained in previous studies. However, after metamorphosis, the correlation between BMF and log KOW was found to coincide with that in previous studies. These results indicate that the biotransformation of pollutants in organisms played a key role in determining whether or not biomagnification occurred in organisms and highlight the potential application of the metabolic rate of chemicals in screening-level risk assessments of new chemicals. Environ Toxicol Chem 2022;41:2395-2403. © 2022 SETAC.

Sex- and size-dependent accumulation of Dechlorane Plus flame retardant in a wild frog-eating snake Amphiesma stolata.

Despite several studies having addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, there is still a dearth of information for reptiles in general and for snakes in particular. Here, we report the residue levels and trophic transfer of syn-, anti-, and anti-Cl11-DP in a frog-eating snake-namely, the striped keelback snake Amphiesma stolata-from a DP hotspot in South China. The concentrations of syn-, anti-, and anti-Cl11-DP in A. stolata ranged from 1.06-21.2, 2.13-21.5, and 0.16-10.6 ng/g lipid weight, respectively, with significantly higher levels in males compared with females. Statistical analysis showed that the concentrations of these chemicals were negatively correlated with body sizes (length and mass) of the snake. The fractional abundance of anti-DP (fanti) did not significantly differ either between the sexes or between A. stolata and its diet (i.e., frogs). However, fanti showed positive correlations with the snake's body size and negative correlations with ∑DP concentrations (summed concentrations of syn- and anti-DP), indicating that body size and DP residue levels are important factors influencing DP isomeric profiles in these snakes. Biomagnification factors estimated based on the relationship between A. stolata and frogs were 0.49 ± 0.01 (mean ± SE), 0.44 ± 0.09, and 1.79 ± 0.54 for syn-, anti-, and anti-Cl11-DP, respectively, suggesting trophic dilution of syn- and anti-DP and a mild biomagnification of anti-Cl11-DP from frogs to snakes.

Bioaccumulation and maternal transfer of two understudied DDT metabolites in wild fish species.

While the secondary metabolites of DDT such as 2,2-bis(chlorophenyl)-1-chloroethylene (DDMU) and 2,2-bis(chlorophenyl)methane (DDM) have been detected in the environment for several decades, knowledge is extremely limited on their bioaccumulation characteristics. Here, we reported the bioaccumulation and maternal transfer of p,p'-DDMU and p,p'-DDM in two wild fishes, i.e., the northern snakehead (Channa argus) and crucian carp (Carassius auratus), from a DDT contaminated site in South China. The hepatic concentrations of p,p'-DDMU and p,p'-DDM in the fish were up to 549 and 893 ng/g lipid weight, contributing 5.3% and 3.2% in average to ΣDDXs (the sum concentrations of DDT and its 6 metabolites), respectively. The residues of p,p'-DDMU and p,p'-DDM in the fish exhibited interspecific and intraspecific variations, resulting from the differences in lipid content, sex, and body sizes (length and mass) between or within species. Both p,p'-DDMU and p,p'-DDM were consistently detected in the fish eggs, demonstrating their maternal transfer in female fish. The mean eggs to liver lipid-normalized concentration (E/L) ratios of p,p'-DDMU and p,p'-DDM were 0.98 and 1.77 in the northern snakehead, 0.35 and 0.01 in crucian carp, respectively; which were comparable to or even exceeded those of DDT and its major metabolites calculated in the same individual. Statistical analyses of the data showed that the E/L ratios were positively correlated with body sizes of the fish, but negatively correlated with the hepatic concentrations of p,p'-DDMU and p,p'-DDM in females; suggesting the influences of fish sizes and the mother body residues on their maternal transfer efficiencies.

Halogenated flame retardants in wild, prey-sized mud carp from an e-waste recycling site in South China, 2006-2016: Residue dynamics and ecological risk assessment.

The crude e-waste recycling has been regulated in China since the late 2000s; however, information on the recent levels and the ecological risks of e-waste derived contaminants such as halogenated flame retardants (HFRs) in the e-waste sites are limited. We therefore examined the concentrations of several HFRs in wild, prey-sized mud carps collected from a typical e-waste site in 2006, 2011 and 2016, to understand the exposure dynamics and ecological risk of these chemicals. Several ecological and biological parameters including δ15N, δ13C, body size and lipid content of the fish were also examined, to ensure an overall uniformity of the sample set among the sampling years. Among the HFRs measured, polybrominated diphenyl ethers (PBDEs) were detected at the highest concentrations (contributing >90% to ∑HFRs), followed by Dechlorane Plus (DPs), polybrominated biphenyls (PBBs), and alternative brominated flame retardants (ABFRs). The fish concentrations of ∑PBDEs, ∑PBBs and ∑DPs significantly dropped by 65%, 57% and 53% from 2006 to 2011, and 12%, 74% and 51% from 2011 to 2016, respectively; likely reflecting the positive impact of the environmental regulations on crude e-waste recycling. The ∑ABFRs concentrations were also decreased by 80% from 2006 to 2011, but increased by 127% from 2011 to 2016; suggesting possible fresh input of these novel HFRs in recent years. In addition to the changes in the HFR concentrations, contaminant profiles in the fish were also changed, possibly due to environmental degradation of the HFRs. Despite our conservative method of risk assessment, we found that PBDEs posed an important risk both for the mud carp and for piscivorous wildlife that inhabit the e-waste site.

Tissue-Specific Distribution of Legacy and Emerging Organophosphorus Flame Retardants and Plasticizers in Frogs.

Five types of tissues, including the liver, kidney, intestine, lung, and heart, were collected from black-spotted frogs and bullfrogs to study the tissue-specific accumulation of organophosphorus flame retardants (PFRs) and plasticizers. Thirteen PFRs and nine plasticizers were detected, with average total concentrations of 1.4-13 ng/g ww and 858-5503 ng/g ww in black-spotted frogs, 3.6-46 ng/g ww and 355-3504 ng/g ww in bullfrogs. Significant differences in pollutant concentrations among different tissues in the two frog species were found, indicating the specific selectivity distribution of PFRs and plasticizers. Overall, liver tissues exhibited significantly higher pollutant concentrations. The pollutant concentration ratios of other tissue to the sum of liver tissue and other tissues (OLR, Cother/(Cother + Cliver)) corresponding to male frogs were significantly greater than those of females, suggesting that male frogs could have higher metabolic potentials for PFRs and plasticizers. No obvious correlations between OLR and log KOW were found, indicating that the other factors (e.g., bioaccumulation pathway and metabolism) besides lipophicity could influence the deposition of PFRs and plasticizers in frog livers. Different parental transfer patterns for PFRs and plasticizers were observed in frogs when using different tissues as parental tissues. Moreover, the liver tissues had similar parental transfer mechanism with muscle tissues.

Legacy and alternative plasticizers in surface sediment of black-odorous urban rivers across China: Occurrence, spatial distribution, and ecological risk assessment.

In this study, surface sediment samples from 173 black-odorous urban rivers in 74 cities of China were investigated regarding the occurrence, spatial distribution, and ecological risk of legacy phthalates (LPs) and alternative plasticizers (APs). The total concentrations of Σ7LPs and Σ6APs ranged from 0.0035 to 522 µg/g dw (median: 33 µg/g dw; mean: 60 µg/g dw) and from 0.0015 to 16 µg/g dw (median: 16 µg/g dw; mean: 2.2 µg/g dw), respectively. Di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-iso-butyl phthalate (DiBP) were the dominant LPs, and di-iso-decyl phthalate and di-iso-nonylcyclohexane-1,2-dicarboxylate were the dominant APs. The concentrations and compositions of the LPs and APs varied among different sites and regions, implying location-specific use or production of LPs and APs. The pollutant concentrations in southern and central China were higher than those in northern China. Among the seven regions, Northwest China had the lowest concentrations of LPs and APs. This could be related to industry development level, municipal facilities, and population density. Total organic carbon (TOC) was significantly and positively correlated with the pollutant concentrations, implying that TOC could be an important influencing factor for the distribution of LPs and APs in sediments. The risk quotients of DiBP and DnBP in almost all sediment samples were above 1, indicating the high ecological risks to aquatic organisms. Nevertheless, DEHP, di-methyl phthalate, di-ethyl phthalate, and di-n-octyl phthalate showed low or moderate ecological risks for most sampling sites.

Determination of tetrabromobisphenol-A/S and their eight derivatives in abiotic (soil/dust) samples using ultra-high performance liquid chromatography-tandem mass spectrometry.

Tetrabromobisphenol-A and Tetrabromobisphenol-S (TBBPA/S) and their derivatives have attracted widespread attention owing to their environmental risks and adverse effects on human health. In this study, we developed an analytical method based on ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of TBBPA/S and their eight derivatives in soil samples. After ultrasonic extraction, TBBPA/S and their derivatives were purified using an LC-Si cartridge with 1 mL acetone and 30 mL dichloromethane/n-hexane (1/1, v/v) as the eluent. In the multiple reaction monitoring (MRM) mode, TBBPA and TBBPS were quantified with electrospray ionization (ESI), whereas their derivatives were quantified with atmospheric pressure chemical ionization (APCI). The proposed method was verified with blank spiking and matrix spiking experiments. All target compounds were recovered at the range of 78-124% and the average recoveries of surrogate standard 13C12-labeled TBBPA were 103% and 99% in spiked blank and soil samples, respectively. The method quantitative limits (MQLs) of TBBPA/S and their derivatives in soil samples ranged from 0.22 to 8.8 pg/g dw. These results indicated that an effective method was provided for the analysis of TBBPA/S and their derivatives in abiotic matrices.