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Electrical and electronic waste (e-waste) has become a global concern, especially in developing countries. In this review, we conducted a literature survey of e-waste management practices, processing activities, and adverse effects in Vietnam, an emerging country in Southeast Asia, by gathering data from peer-reviewed articles published between 2009 and 2021. This is the first review paper to comprehensively discuss management and research aspects regarding e-waste in an Asian developing country. Due to the lack of an effective management and recycling system, a certain portion of Vietnamese e-waste has been processed by informal sectors without appropriate recycling and pollution control technology, resulting in localized contamination and human exposure to toxic chemicals. Primitive processing activities, such as manual dismantling, open burning, and plastic recycling, have been identified as important contributors to the environmental emission and human exposure to toxic elements (notably As, Mn, Ni, Pb, Zn) and organic pollutants like flame retardants, PAHs, PCBs, and dioxin-related compounds. Informal e-waste processing from these small-scale workshops can release pollutants at similar levels compared to large-scale facilities in developed countries. This fact suggests an urgent need to develop management best practices for e-waste in Vietnam as well as other emerging and developing countries, in order to increase recycling efficiency and minimize their adverse impacts on environmental and human health.

In Asian developing countries, undeveloped and ineffective sewer systems are causing surface water pollution by a lot of contaminants, especially pharmaceuticals and personal care products (PPCPs). Therefore, the risks for freshwater fauna need to be assessed. The present study aimed at: i) elucidating the contamination status; ii) evaluating the bioaccumulation; and iii) assessing the potential risks of PPCP residues in surface water and freshwater fish from three Asian countries. We measured 43 PPCPs in the plasma of several fish species as well as ambient water samples collected from India (Chennai and Bengaluru), Indonesia (Jakarta and Tangerang), and Vietnam (Hanoi and Hoa Binh). In addition, the validity of the existing fish blood-water partitioning model based solely on the lipophilicity of chemicals is assessed for ionizable and readily metabolizable PPCPs. When comparing bioaccumulation factors calculated from the PPCP concentrations measured in the fish and water (BAF

This study was conducted to find out characteristics of trace element levels and those impacts to organisms at a former uranium (U) mining site. Concentrations of trace elements (Li, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Cs, Ba, Pb, Bi, and U) were determined in sediments, water, and three organism types (insects, frogs, and newts) from three zones in the former U mining site, Ningyo-toge in Japan. Concentrations of As and U in the sediments and water samples were the highest at the mill tailings pond (MP) site, where post-U extraction remnants have been accumulated. Additionally, among the organisms analyzed the highest concentrations of these elements/isotopes were found in newts from MP. Considering data analyses of the whole-body element concentrations, bioaccumulation factors, and δ

Hatchery-reared Atlantic salmon (Salmo salar) has been released to support the wild salmon stocks in the Baltic Sea for decades. During their feeding migration, salmon are exposed to organohalogen compounds (OHCs). Here, we investigated the OHC levels and transcriptome profiles in the liver of wild and hatchery-reared salmon collected from the Baltic main basin (BMB), the Bothnian Sea (BS), and the Gulf of Finland (GoF) and examined whether salmon origin and OHC levels contributed to the hepatic transcriptome profiles. There were no differences in the OHC concentrations between wild and reared fish but larger differences between areas. Several transcript levels were associated with non-dioxin-like polychlorinated biphenyls, polybrominated diphenylethers, chlordanes, and dichlorodiphenyltrichloroethane in a concentration-dependent manner. Between wild and reared salmon, lipid metabolism and related signaling pathways were enriched within the BMB and BS, while amino acid metabolism was altered within the GoF. When comparing the different areas, lipid metabolism, environmental stress and cell growth, and death-related pathways were enriched. Class coinertia analysis showed that the covariation in the OHC levels and the transcriptome were significantly similar. These results suggest that the hepatic transcriptomes in wild and hatchery-reared salmon are more affected by the OHC levels rather than the origin of salmon.

Estrogen, androgen, and glucocorticoid receptors (ER, AR, and GR) agonist activities in river water samples from Chennai and Bangalore (India), Jakarta (Indonesia), and Hanoi (Vietnam) were evaluated using a panel of chemical-activated luciferase gene expression (CALUX) assays and were detected mainly in the dissolved phase. The ER agonist activity levels were 0.011-55 ng estradiol (E2)-equivalent/l, higher than the proposed effect-based trigger (EBT) value of 0.5 ng/l in most of the samples. The AR agonist activity levels were 2.1-110 ng dihydrotestosterone (DHT)-equivalent/l, and all levels above the limit of quantification exceeded the EBT value of 3.4 ng/l. GR agonist activities were detected in only Bangalore and Hanoi samples at dexamethasone (Dex)-equivalent levels of 16-150 ng/l and exceeded the EBT value of 100 ng/l in only two Bangalore samples. Major compounds contributing to the ER, AR, and GR agonist activities were identified for water samples from Bangalore and Hanoi, which had substantially higher activities in all assays, by using a combination of fractionation, CALUX measurement, and non-target and target chemical analysis. The results for pooled samples showed that the major ER agonists were the endogenous estrogens E2 and estriol, and the major GR agonists were the synthetic glucocorticoids Dex and clobetasol propionate. The only AR agonist identified in major androgenic water extract fractions was DHT, but several unidentified compounds with the same molecular formulae as endogenous androgens were also found.

Persistent organochlorine chemicals (OCs), including chlordane compounds (CHLs), DDTs, PCBs, and chlorinated dioxins and related compounds (DRCs), were examined in the adipose tissue and liver from 33 specimens of habu (Protobothrops flavoviridis), a species of venomous pit viper endemic to the Japanese Southwest Islands. The median concentrations of CHLs, DDTs, and PCBs in adipose tissue of 22 habus collected from an urban area were 4400 ng g−1 lipid weight (lw), 610 ng g−1 lw, and 1600 ng g−1 lw, respectively. Their DDT and PCB concentrations were higher in comparison with the specimens from a rural area. Liver of 10 specimens from the urban area were subjected to DRCs analysis, and PCDDs, PCDFs, and DL-PCBs were detected with median values of 1300, 350, and 150,000 pg g−1 lw, respectively. Among PCDD/F congeners, octa-CDD was detected at the highest concentrations in seven liver samples, but considerable concentrations of penta- and hexa-CDD/Fs were found in two samples. Relatively higher concentrations of PCB, DDTs, and PCDD/Fs were found in habus collected within 1 km of the boundary of military facilities, suggesting that OCs from some unknown sources of these OCs inside and/or around some of the facilities accumulated in habus.

Recent screening surveys have shown the presence of unknown halogenated compounds in the marine environment at comparable levels to persistent organic pollutants (POPs). However, their exposure levels and profiles in marine organisms and bioaccumulative potentials remain unclear. The present study performed nontarget/target screening of organohalogen compounds (OHCs) in mussel and sediment samples collected from Hiroshima Bay, Japan, in 2012 and 2018 by using integrated analyses of two-dimensional gas chromatography-high resolution time-of-flight mass spectrometry (GC×GC-HRToFMS) and magnetic sector GC-HRMS. Nontarget analysis by GC×GC-HRToFMS revealed the detection of approximately 60 OHCs including unknown mixed halogenated compounds (UHC-Br3-5Cl) with molecular formulae of C9H6Br3ClO, C9H5Br4ClO, and C9H4Br5ClO in the mussel. Interestingly, UHC-Br3-5Cl concentrations in the mussel samples, which were semi-quantified by GC-HRMS, were comparable to or higher than those of POPs at all the locations surveyed, and their geographical distribution patterns differed from those of other OHCs. These results suggest that UHC-Br3-5Cl are ubiquitous in coastal waters of Hiroshima Bay and derived from a specific source(s). The biota-sediment accumulation factors (BSAFs) of UHC-Br3-5Cl, estimated for a paired sample set of mussel (ng/g lw) and sediment (ng/g TOC), were 1 order of magnitude higher than those for POPs with similar log Kow values, indicating their high bioaccumulative potential.

Several naturally occurring dioxins, including 1,3,7-tribromodibenzo-p-dioxin (1,3,7-TriBDD), synthesized by red algae, have been detected in the marine environment. As 1,3,7-TriBDD is accumulated in mussels and fish, predators, such as marine birds, are exposed to this congener, similar to anthropogenic dioxins (including 2,3,7,8-tetrachlorodibenzo-p-dioxin TCDD). However, little is known about the impact of 1,3,7-TriBDD exposure on the bird health. To understand the effects of 1,3,7-TriBDD on birds, the phenotypic effects and hepatic transcriptome were investigated in chicken (Gallus gallus) embryos treated with 27 μM (2.9 ng/g egg) and 137 μM (14.4 ng/g egg) 1,3,7-TriBDD. The blood glucose levels in the 1,3,7-TriBDD-treated groups were lower than those in the control group. The transcriptome analysis of 6520 sequences in the 27 and 137 μM 1,3,7-TriBDD-treated groups identified 733 and 596 differentially expressed genes (DEGs). Cytochrome P450 1A4 and 1A5 were also identified as DEGs, suggesting that the aryl hydrocarbon receptor is activated by this congener. Pathway and network analyses with DEGs suggested that 1,3,7-TriBDD may induce carcinogenic effects and metabolic alterations. These results were similar to the effects on TCDD-treated embryos. Nevertheless, the overall transcriptome results suggested that compared with TCDD, 1,3,7-TriBDD has a unique impact on insulin- and peroxisome-signaling pathways in chicken embryos. Differences in altered transcriptome profiles between 1,3,7-TriBDD- and TCDD-treated embryos may lead to different phenotypic effects: less severe effects of 1,3,7-TriBDD and more fatal effects of TCDD. Collectively, these findings warrant the further assessment of the hazard and risk of 1,3,7-TriBDD on marine animals, considering increased exposure due to climate change.

Reactive sulfur species (RSS), such as hydrogen per (poly)sulfide, cysteine per (poly)sulfide, glutathione per (poly)sulfide, and protein-bound per (poly)sulfides, can easily react with environmental electrophiles such as methylmercury (MeHg), because of their high nucleophilicity. These RSS are produced by enzymes such as cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) and are found in mammalian organs. Organs of wildlife have not been analyzed for hydrogen sulfide, cysteine, glutathione, and RSS. In this study, low molecular weight nucleophilic sulfur substances, including RSS, were quantified by stable isotope dilution assay-based liquid chromatography-mass spectrometry using β-(4-hydroxyphenyl)ethyl iodoacetamide to capture the target chemicals in the small Indian mongoose which species possesses high mercury content as same as some marine mammals. Western blotting revealed that the mongoose organs (liver, kidney, cerebrum, and cerebellum) contained proteins that cross-reacted with anti-CBS and CSE antibodies. The expression patterns of these enzymes were similar to those in mice, indicating that mongoose organs contain CBS and CSE. Moreover, bis-methylmercury sulfide (MeHg)

Thyroid hormones (THs) play a critical role in the regulation of biological processes, such as growth, metabolism, and development, in various animal species. Prohormone L-thyroxine (T4) is secreted from the thyroid gland and carried to peripheral tissues. T4 is then biotransformed to several metabolites which play different roles, mainly by iodothyronine deiodinases. Determination of deiodinated TH metabolites in key organs such as liver and brain would help to understand tissue-specific TH metabolism and homeostasis. In this study, we thus developed a highly sensitive method for the determination of six THs [T4, 3,5,3'-triodo-L-thyronine (T3), 3,3',5'-triiodo-L-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2), 3,3'-diiodo-l-thyronine (3,3'-T2), and 3-iodo-l-thyronine (3-T1)] in the brain and liver by using stored dog samples. The analytical method consisted of ultrasonic-assisted extraction in acetone acidified with formic acid, cleanup with a EVOLUTE® EXPRESS CX cartridge (reversed-phase combined with strong cation-exchange cartridge), and quantification with liquid chromatography-tandem mass spectrometry. Acceptable accuracy (internal standard-corrected recovery: 80%-120%) and intra- and inter-day precision (coefficient of variation:6% and15%, respectively) (n = 3/ batch, three days) were obtained for both brain and liver samples. In addition, low method detection limits were achieved for both brain (0.013-0.12 ng g

Measuring personal exposure to flame retardants (FRs) is crucial for assessing and controlling human health risks posed by FRs during the recycling of electronic waste (e-waste) and end-of-life vehicles (ELVs). Here, we examined the use of handwipes and silicone wristbands to measure personal FR exposure for e-waste and ELV recycling workers and their children in Vietnam. On the handwipes from the e-waste recycling workers, the predominant five FRs detected were TBBPA (median concentration: 3700 ng/wipe), BDE-209 (1700 ng/wipe), TPHP (500 ng/wipe), DBDPE (410 ng/wipe), and BPA-BDPP (360 ng/wipe). On the handwipes from ELV recycling workers, TPHP (60 ng/wipe), IPPDPP (47 ng/wipe), BIPPPP/DIPPDPP (33 ng/wipe), BDE-209 (26 ng/wipe), and TCIPP (23 ng/wipe) were detected as the five predominant FRs. On the wristbands from the e-waste recycling workers, the five predominant FRs detected were TBBPA (median concentration: 340 ng/g), BDE-209 (330 ng/g), DBDPE (65 ng/g), TPHP (50 ng/g), and TMPP (34 ng/g). On the wristbands from the ELV recycling workers, TPHP (34 ng/g), IPPDPP (18 ng/g), TCIPP (14 ng/g), TDMPP (13 ng/g), BIPPPP/DIPPDPP (9.3 ng/g) and TMPP (9.3 ng/g) were detected as the predominant FRs. The data obtained with the wristbands were comparable to those obtained with the handwipes. Similar FR profiles were found in between the workers and their children. The profiles indicate that the informal e-waste and ELV recycling caused FR exposure not only for workers but also for their children who live in the workshops. By using the handwipe and wristband sampling approaches, we determined types and concentrations of FRs to which the workers and their children were dominantly exposed. Silicone wristband- and handwipe-based assessment is expected to be effective means of measuring personal FR exposure for the informal e-waste and ELV recycling workers and their children.

Information about the co-occurrence of halogenated flame retardants (HFRs) and organophosphate esters (OPEs) in the environment of informal waste processing areas is still limited, especially in emerging and developing countries. In this study, OPEs and HFRs including polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and chlorinated flame retardants (CFRs) were determined in settled dust from Vietnamese e-waste recycling (WR) and vehicle processing (VP) workshops. Pollutant concentrations decreased in the order: OPEs (median 1500; range 230-410,000 ng/g) ≈ PBDEs (1200; 58-250,000) NBFRs (140; not detected - 250,000) CFRs (13; 0.39-2200). HFR and OPE levels in the WR workshops for e-waste and obsolete plastic were significantly higher than in the VP workshops. Decabromodiphenyl ether and decabromodiphenyl ethane are major HFRs, accounting for 60 ± 26% and 25 ± 29% of total HFRs, respectively. Triphenyl phosphate, tris(2-chloroisopropyl) phosphate, and tris(1,3-dichloroisopropyl) phosphate dominated the OPE profiles, accounting for 30 ± 25%, 25 ± 16%, and 24 ± 18% of total OPEs, respectively. The OPE profiles differed between WR and VP dust samples, implying different usage patterns of these substances in polymer materials for electric/electronic appliance and automotive industries. Human health risk related to dust-bound HFRs and OPEs in the study areas was low.

The environmental contamination by benzotriazole ultraviolet stabilizers (BUVSs) has received consider attention due to their long-term and widespread usage in various consumer and industrial products in accordance with solar UV radiation increase. The present study shows the baseline data of BUVSs in human breast milk from several areas in Japan, the Philippines, and Vietnam. Total concentrations of the 8 BUVSs in breast milk ranged fromMDL (method detection limit) to 1100 ng/g lipid wt. in present study. Among the 8 BUVS compounds targeted, the highest concentration of UV-9 was found in breast milk samples collected from Vietnam. The concentrations of BUVSs in human breast milk were significantly higher (p 0.01) in Vietnam (300 ± 240 ng/g lipid wt.) than in the Philippines (100 ± 130 ng/g lipid wt.) and Japan (28 ± 34 ng/g lipid wt.). The estimated daily intake of BUVSs by infants through breast milk was one or two orders of magnitude lower than the reference dose levels.

We evaluated the possibility of semi-automatic target and non-target screening by comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRToFMS) by using estuarine sediment samples. Two-way screening consisting of compound-based (target screening) and data-based (non-target screening) analyses was performed by using two original software programs, including mass-spectral deconvolution software based on non-negative matrix factorization, the NIST Mass Spectral Library, and an in-house accurate mass spectral library with a retention index (RI) for the 1st column. Target screening detected 47 organohalogen compounds, including polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides, in the sediment sample. Among about 54,000 peaks detected in the non-target screening, 53.6% showed match factors (MF) of ≥ 700 in an automatic mass spectral library search using the peak-top mass spectra. Both mass error of molecular ions and RI error were calculated automatically for the first-hit compounds in the library search; 0.03% of peaks passed all criteria, namely MF ≥ 700, mass error ≤± 20 ppm, RI error ≤ ± 20, and intensity of molecular ion ≥ 10,000. Two compounds—a phosphorus flame retardant and a brominated phenol—were tentatively identified in the non-target screening process. The advantages of semi-automatic GC×GC-HRToFMS data processing with the two original software programs is its simplicity, high reproducibility, and shortened time for processing a large volume data. The results suggest that an In-source HiRes search—i.e. library matching using accurate mass spectra—is useful and could be applied for non-target screening using high-resolution MS in the future.

Plastic pollution has become one of the most pressing environmental issues. Recycling is a potential means of reducing plastic pollution in the environment. However, plastic fragments are still likely released to the aquatic environment during mechanical recycling processes. Here, we examined the plastic inputs and effluent outputs of three mechanical recycling facilities in Vietnam dealing with electronic, bottle, and household plastic waste, and we found that large quantities of microplastics (plastics5 mm in length) are generated and released to the aquatic environment during mechanical recycling without proper treatment. Comparisons with literature data for microplastics in wastewater treatment plant effluents and surface water indicated that mechanical recycling of plastic waste is likely a major point source of microplastics pollution. Although there is a mismatch between the size of the microplastics examined in the present study and the predicted no-effect concentration reported, it is still possible that microplastics generated at facilities pose risks to the aquatic environment because there might be many plastic particulates smaller than 315 μm, as suggested by our obtained size distributions. With mechanical recycling likely to increase as we move to a circular plastics economy, greater microplastics emissions can be expected. It is therefore an urgent need to fully understand not only the scale of microplastic generation and release from plastic mechanical recycling but also the environmental risk posed by microplastics in the aquatic environment.

This review provides focused insights into the contamination status, sources, and ecological risks associated with multiple classes of antibiotics in surface water from the East and Southeast Asia based on publications over the period 2007 to 2020. Antibiotics are ubiquitous in surface water of these countries with concentrations ranging from

Striped dolphins (Stenella coeruleoalba) mass-stranded on 26 April 2013 at Minamisatsuma, Kagoshima Prefecture, in southern Japan (East China Sea). The diet of the mass-stranded striped dolphins was investigated to reveal their foraging pattern through analyses of the stomach contents and stable isotopes in muscle. Of 26 stomachs sampled, 25 contained hard parts of prey animals; no fleshy remains were found in any of the stomachs. The identified prey species represented four cephalopod families: Loliginidae, Onychoteuthidae, Histioteuthidae, and Ommastrephidae. Among these, ommastrephids had the highest abundance (42.4%) and frequency of occurrence (69.2%). A chi-square test revealed that the prey species consumed did not significantly differ between male and female dolphins, although deeper-water squids (Onychoteuthidae and Histioteuthidae) appeared only in the stomachs of females. The values of δ13C ranged from –20.4 to –17.0‰ (mean ± SD: –18.2 ± 0.9‰), and values of δ15N ranged from 10.2 to 12.5‰ (10.8 ± 0.5‰), with a significant difference in δ15N between sexes (P < 0.05).

Contamination levels and temporal trends of polybrominated diphenyl ethers (PBDEs) and some alternative brominated flame retardants (BFRs) were examined in a dated sediment core from the deepest part of the Beppu Bay, southwestern Japan. PBDEs were found in the upper layers of 0–15 cm depth at concentrations ranging from 5200 to 32,600 pg g−1 with the peak estimated at 1995. Decabromodiphenyl ether (BDE-209) was the most abundant congener, accounting for 96% in average of total PBDEs. The vertical profile of BDE-209 observed in our sediment core generally agreed with the historical pattern of domestic demand of commercial deca-BDE mixtures in Japan, and perfectly matched with maximum stock of these products (i.e., 42,000 tons in 1995). Among alternative BFRs, only decabromodiphenyl ethane (DBDPE), a replacement of deca-BDE, was found at significant levels with concentrations of 69–850 pg g−1 in sediment layers dated between 1991 and 2011. Ratios of DBDPE to BDE-209 gradually increased during this period, implying opposite trends of these two compounds and the role of DBDPE as a deca-BDE’s alternative. The occurrence of deca-BDE components in sediments may pose medium risk to benthic aquatic life, while the ecological risk of other PBDE homologs and DBDPE was negligible.

Previous studies have suggested that unidentified compounds constitute a large proportion of extractable organochlorine (EOCl) and extractable organobromine (EOBr) in the crude extracts without fractionation; however, the proportion of unidentified EOX (X = chlorine, bromine) associated with high-/low-molecular-weight compounds is still unknown. In this study, we applied gel permeation chromatography to fractionate extracts from archived liver samples of high-trophic marine and terrestrial mammals (striped dolphins, cats, and raccoon dogs), for which concentrations of legacy organohalogen contaminants (polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers [PBDEs]) had been previously reported. EOX in high- (1000 g/mol) and low- (≤1000 g/mol) molecular-weight fractions (EOX-H and EOX-L) were determined by neutron activation analysis. Comparison of EOCl and EOBr enabled the characterization among species. Despite small differences in the concentrations and molecular-weight profiles of EOCl among species, the contribution of chlorine in identified compounds to EOCl-L varied from 1.5% (cats) to 79% (striped dolphins). Considerable species-specific variations were observed in the concentrations of EOBr: striped dolphins exhibited significantly greater concentrations of both EOBr-H and EOBr-L than cats and/or raccoon dogs. Moreover, the contribution of bromine in PBDEs to EOBr-L was50% in two cats, while it was6% in other specimens. This is the first report on EOBr mass balance in cetaceans and on EOX mass balance in terrestrial mammals living close to humans. These results suggest the need for analysis of unidentified chlorinated compounds in terrestrial mammals and unidentified brominated compounds in marine mammals.

Food matrices are naturally complex and many ingredients such as lipids, proteins, pigments and others are co-extracted with PCBs. So, reliable and effective analytical techniques are needed to determine PCBs in foodstuffs at low concentration. This review is exploring and summarizes the current available techniques for extraction, clean-up, and separation techniques to quantify the PCBs in different foods. Several extraction approaches have been improved to overcome the issues associated with regular techniques involves large amount of solvent and time consuming. Accelerated solvent extraction is a promising and effective extraction technique using reasonable amount of solvents. Acidified silica gel alone or in combination with alumina is succeeded to purify most extract matrices. Besides, gel permission chromatography is widely used to eliminate large size molecules and other co-extracted impurities. As a reference technique GC-HRMS is the most effective technique for quantification of dioxins and dioxin-like PCBs. As alternative techniques, GC coupling with tandem MS is optimized to analysis dioxin and PCBs in foodstuffs and represent a cost effectiveness technique compared to GC-HRMS. GCxGC-HRTOF-MS is evaluated and validated to examine dl-PCBs and indicator PCBs and the obtained results were satisfactory well equivalent to those results obtained by GC-HRMS.

Contamination levels and profiles of mono- to deca-chlorinated biphenyls (PCBs) were characterized in a sediment core dated in 1954–2011 from Beppu Bay, southwestern Japan, providing a comprehensive and detailed picture on the environmental occurrence, temporal trends, and emission sources of these pollutants in the study area. Concentrations of total PCBs in the core ranged from 3.5 to 150 (median 15) ng g−1 dry weight and exhibited depth profile matching with Japanese PCB production and emission patterns (i.e., drastically increasing from the early 1960s, peaking in 1970, and then rapidly decreasing). Origin of PCBs in the studied samples largely associated with Kanechlor mixtures (e.g., KC-300 and KC-400), especially for sediment layers dated between the mid-1960s and early 1970s (i.e., the intensive PCB production period in Japan). In addition, dechlorination and weathering signals and emerging inputs of PCBs were also observed in deeper and shallower sediment segments with notable proportions of some unique congeners such as CB-47/48/51 and CB-11, respectively. Historical fluxes of PCBs in our samples showed quite similar vertical shape as concentrations. In the context of national implementation for complete treatment of PCB-containing waste until 2024, further investigations on spatiotemporal trends and environmental loads of PCBs in Japan are necessary.

Flame retardants (FRs) from electronic waste (e-waste) are a widespread environmental concern. In our study, in vitro physiologically based extraction tests (PBETs) for FRs were conducted in three different areas where dust remained after processing of e-waste to identify the bioaccessible FRs and quantify their bioaccessibilities of gastrointestinal tract for human as well as to assess the exposure via ingestion of workers in e-waste processing workshops. All 36 FRs were measured and detected in indoor dusts. Among the FRs, the mean concentrations of polybrominated diphenyl ethers (PBDEs) in the floor dust and settled dust were highest, 65,000 ng/g, and 31,000 ng/g, respectively. In contrast, phosphorus-containing flame retardants (PFRs) presented the highest mean concentration in the workplace dust samples, 64,000 ng/g. However, the highest bioaccessible concentrations in workplace dust, floor dust, and settled dust were observed for PFRs: 5900, 1600, and 680 ng/g, respectively. This study revealed that the higher bioaccessibility of PFRs versus other compounds was related to the negative correlation between FR concentrations and log KOW (hydrophobicity) values. The fact that hazard indices calculated using measured bioaccessibilities were less than 1 suggested that the non-cancer risk to human health by the FRs exposure via dust ingestion might be low.

Concentrations of 26 trace elements including essential (Mg, Ca, Cr, V, Mn, Fe, Co, Ni, Cu, Zn, Se, Sr and Mo) and toxic (As, Cd and Pb), were determined in the liver, kidney, brain, hair, muscle, and stomach contents of the small Indian mongooses inhabiting eight areas on three Hawaiian Islands, Oahu, Maui and Hawaii. There were significant differences in concentrations of some metals among the habitats. Cadmium concentrations in mongooses from the macadamia nut orchards on Island of Hawaii were relatively higher than those in populations from other seven areas. Lead concentrations in mongooses from the Ukumehame firing range were significantly higher than those from other areas. Compared to data reported in mongooses from other countries, Pb concentrations in the brain were higher in the animals from Hawaiian islands, but almost similar levels were observed in the liver and kidney. Intriguingly, brain concentrations of Pb in three specimens from the Ukumehame firing range exceeded 3.79 µg g−1 WW, which was the mean cerebral Pb level in rats that caused some toxic symptoms after administration in the previous study. Furthermore, two fetuses exhibited higher brain Pb concentrations than each of their dams. These results prompted us to consider the potential exposure and health effects of Pb derived from firing range operations on the small Indian mongoose and other animal species including human.

Thyroid hormones (THs), which mainly consist of 3, 3', 5-triiodo-l-thyronine (T3) and L-thyroxine (T4), play a critical role in regulating biological processes such as growth and metabolism in various animal species. Thus, accurate measurement of T3 and T4, especially physiologically active free (protein-unbound) forms, in serum/plasma is needed for the evaluation of TH homeostasis. However, such high-precision determination of free THs is lacking for non-human species. The present study aimed to develop a highly sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of six free THs in serum/plasma, which is applicable to not only humans but also non-human species. Two different physical separation steps, ultrafiltration (UF) and equilibrium dialysis (ED), were examined to obtain the free TH fraction. Several experimental conditions were carefully optimized and validated for UF or ED using the commercially available bovine serum. As a result, UF at 1100 × g and 37 °C for 30 min with a 30 kDa ultrafiltration device (Centrifree YM-30, Millipore) yielded excellent precision (CV:10%). The optimized ED step also yielded high precision (CV:10%) and the measurement values were approximately equal to those of UF, but at least 16 h were required to reach equilibrium. Thus, UF combined with LC-MS/MS was finally chosen, in terms of the time needed for the measurement. Acceptable accuracy (recovery: 70%-110%) and intra- and inter-day precision (CV:10% and12%, respectively) were obtained, when triplicate analyses in three different days were conducted using the bovine serum. The developed analytical method was successfully applied to the determination of free THs in serum/plasma samples of humans, cats, and dogs. Furthermore, comparison with free T4 concentrations measured by a common immunoassay method evidently indicated that the ultrafiltration-LC-MS/MS method developed in this study can increase the specificity and accuracy of TH measurement.

The development of highly selective and sensitive analytical methods for the nontarget screening of persistent organic pollutants such as halogenated compounds in environmental samples is a challenging task. Soft ionization mass spectrometry has emerged as a powerful technique for obtaining essential molecular information, and it is expected to reveal compounds that remain hidden with conventional fragmentation techniques such as electron ionization (EI). In this study, a soft ionization method based on electron capture negative ionization using an inert gas was developed for the nontarget screening of chlorinated aromatics in environmental samples and was applied to comprehensive two-dimensional gas chromatography–high-resolution time-of-flight mass spectrometry (GC × GC–HRToFMS). In particular, argon (Ar) and helium (He) were evaluated as inert moderating gases, and were compared against the conventional methane (CH4). The optimal ionization conditions, including the flow rate and ion source temperature, were investigated based on the molecular ion intensities of highly chlorinated aromatics decachlorobiphenyl and octachlorodibenzofuran. Ar-mediated soft ionization provided the best sensitivity to molecular ions among the three gases at a low flow rate (0.1 mL min−1) and low ion source temperature, and more selective detection of molecular ions (i.e., less fragmentation) was obtained with the inert gases than with CH4. This method is also applicable to other chlorinated aromatics such as tetra- to nonachlorobiphenyls, tetra- to heptachlorinated dibenzofurans, pentachlorobenzene, and hexachlorobenzene. To demonstrate the applicability of the proposed method to a wide range of chlorinated aromatics in environmental samples, both Ar-mediated soft ionization and conventional EI were applied to GC × GC–HRToFMS for analysis of a crude extract of house dust. Soft ionization enabled the selective and sensitive detection of molecular ions for minor amounts of chlorinated aromatics, even in complex matrices. Furthermore, the extracted ion chromatograms of halide anions (Cl− or Br−) were useful for screening other chlorinated or brominated compounds in the environmental samples. The results suggest that combining information on halide anions obtained by soft ionization and the structural information provided by EI would constitute a powerful approach for the comprehensive identification of chlorinated aromatics.

Cadmium (Cd) is a non-essential metal widespread in the environment, to which humans are exposed through different routes, being food consumption the most important one. It is considered an endocrine disruptor that is associated with estrogen-dependent diseases with women being particularly susceptible. In order to assess the exposure to this metal through diet intake in premenopausal women, levels of Cd were quantified in 7-days duplicate diet samples provided by 23 women working or studying at University of Aveiro , Portugal. Cd was detected in all analyzed samples with concentrations ranging between 0.007 and 0.21 μg g − 1 ww (median: 0.009 μg g − 1 ww). The estimated dietary weekly intakes varied from 1.4 to 48 μg kg-bw − 1 week − 1 (median: 2.3 μg kg-bw − 1 week − 1 ), and 35% of the participants exhibited dietary intakes of Cd higher than the tolerable weekly intake (2.5 μg kg-bw − 1 week − 1 ) set for this metal which suggest health risks for these women.

Monitoring data on organic pollutants published between the late 1960s and 2020 are reviewed to provide comprehensive and updated insights into their bioaccumulation characteristics, sources, and fate in snakes. Multiple organic pollutant classes including pesticides, polychlorinated biphenyls, chlorinated paraffins, dioxin-related compounds, alkanes, polycyclic aromatic hydrocarbons, flame retardants, plasticizers, etc., were detected in various aquatic and terrestrial snake species with concentrations and patterns varying between species and locations. In general, higher concentrations of organic pollutants were found in snakes collected from contaminated sites (e.g., densely populated, pesticide-treated, and waste processing areas), suggesting that snakes can serve as good biomonitors of environmental pollution caused by organic contaminants. Factors influencing concentrations and patterns of organic pollutants in snakes are discussed, providing an overview of current understanding about their accumulation, transformation, and elimination processes. Potential negative effects associated with organic pollutants in snakes and their predators are also considered. Based on such discussions, research gaps and future perspectives on the utilization of snake biomonitoring studies are addressed, heading towards an effective monitoring and assessment scheme for a variety of legacy and emerging organic pollutants in the environment.

The present study determined recent accumulation levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated diphenyl ethers (PCDEs), methoxylated-PBDEs (MeO-PBDEs) and 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1) in the blubber of melon-headed whales (Peponocephala electra) stranded along the Japanese coastal waters in 2015 and examined temporal trends of these organohalogen compound (OHC) levels by analyzing blubber samples of this species archived in the environmental specimen bank which were collected in 1982, 2001, 2002, 2006, 2010 and 2011. The median concentrations in melon-headed whales stranded recently were in the order of DDTs ≈ PCBs > HBCDDs > Q1 > CHLs > MeO-PBDEs > PBDEs > HCB > HCHs > PCDEs, indicating that considerable amounts of HBCDDs, in addition to DDTs and PCBs, have been transported to tropical and subtropical waters of the open ocean and pelagic whale species might be exposed to relatively high levels of these OHCs. Temporal trend analyses of OHC levels in the blubber of melon-headed whales revealed significant decrease for anthropogenic OCs such as DDTs, PCBs, HCB, HCHs and PCDEs, and significant increase for CHLs, PBDEs, HBCDDs, MeO-PBDEs and Q1 since 1982. Besides, the analyses from 2001 to 2015 showed no decreasing trends (unchanged) for some PCB congeners, p,p’-DDE, cis- and trans-nonachlors, Q1, BDE-47, -100 and −154, and significantly increasing trends for α-HBCDD and 6MeO-BDE47, suggesting their chronic exposure for this pelagic whale species.

Floor dusts from Vietnamese end-of-life vehicle (ELV)-processing households were investigated to elucidate the contamination levels and exposure risk of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and dioxin-related compounds (DRCs). The concentrations were in order of PBDEs (260–11,000, median 280 ng/g overall) > PCBs (19–2200, median 140 ng/g) > dioxin-like PCBs (8.8–450, median 22 ng/g) ≫ polybrominated dibenzo-p-dioxin/dibenzofurans (PBDD/Fs, 2000–28,000, median 8500 pg/g) > polychlorinated dibenzo-p-dioxin/dibenzofurans (PCDD/Fs, 440–4100, median 1800 pg/g) > MoBPCDD/Fs (1.9–1200, median 250 pg/g). Concentrations of PCBs and DRCs were higher than those reported for Vietnamese urban houses, indicating ELV processing as a significant source of these contaminants. Higher concentrations of PCBs relative to PBDEs suggest the abundance of old electrical capacitors/transformers in ELVs. The PBDD/F and PCDD/F profiles were indicative of DecaBDE-containing materials and combustion sources, respectively. PBDFs, PCDFs and DL-PCBs were the most important dioxin-like toxic equivalent (TEQ) contributors. The estimated PCB and TEQ intake doses from dust ingestion approached or exceeded the reference doses for children living in some ELV-processing households, indicating potential health risk. More comprehensive risk assessment of the exposure to PCBs and DRCs is required for residents of informal ELV recycling sites.

Detailed composition of chlorinated and brominated polycyclic aromatic hydrocarbons (Cl-PAHs and Br-PAHs) generated during informal recycling of e-waste and their toxic relevance are still poorly understood. This study investigated the occurrence of Cl-PAHs and Br-PAHs in surface soil samples from the Agbogbloshie e-waste recycling site (Accra, Ghana) using quantitative gas chromatography–mass spectrometry (GC–MS) and comprehensive two-dimensional GC–time-of-flight mass spectrometry (GC × GC–ToFMS) profiling. The results of GC–MS analysis showed elevated concentrations in open e-waste burning areas (160–220 and 19–46 ng/g dry weight for Cl- and Br-PAHs, respectively) with substantial contribution from unidentified compounds (respectively, more than 36 and 70%, based on the total areas of potential peaks). Cl- and Br-PAHs from e-waste burning had a distinctive composition dominated by ring–ring compounds. Several homologue groups not monitored with GC–MS were found using GC × GC–ToFMS: PAHs with up to 5Cl or 3Br, mixed halogenated PAHs and chlorinated methylPAHs. The dioxin-like toxic equivalents of the identified Cl-/Br-PAHs in soils, estimated from their in vitro AhR agonist potencies relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin, were much lower than the range reported for chlorinated and brominated dioxins. However, the toxicity of the unidentified halogenated PAHs remained unclear.

The distribution and toxic equivalents (TEQs) of brominated and chlorinated dibenzo- p-dioxins/dibenzofurans (PBDD/Fs and PCDD/Fs) in soils from Agbogbloshie e-waste site (Ghana) were investigated. The composition of brominated/chlorinated dibenzofurans (PXDFs) and diphenyl ethers (PBDEs, PCDEs, and PXDEs) was examined using two-dimensional gas chromatography-time-of-flight mass spectrometry to elucidate possible formation pathways of dioxins from e-waste recycling. The highest concentrations of PCDD/Fs and PBDD/Fs were found, respectively, in the open burning (1.3-380 ng/g dry weight) and dismantling areas (11-1000 ng/g dry weight) and were comparable to the highest reported for informal e-waste sites. PXDFs and PXDEs were detected at up to the range of hundreds of nanograms per gram. The homologue profiles suggest that PXDFs were formed mainly from PBDFs through successive Br-to-Cl exchange. However, monobromo-PCDFs were also derived from de-novo-generated PCDFs in open burning areas. PBDFs contributed similar or higher TEQs (7.9-5400 pg/g dry weight) compared with PCDD/Fs (6.8-5200 pg/g dry weight), whereas PXDFs were also substantial TEQ contributors in open burning areas. The high TEQs of PBDFs in the dismantling area (120-5200 pg/g dry weight) indicate the need to consider brominated dioxins besides chlorinated dioxins in future studies on health implications for e-waste workers and local residents.

Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) might disrupt thyroid function. However, there is no clear evidence of PCB exposure disrupting thyroid hormone (TH) homeostasis in dogs and cats. The present study conducted in vivo experiments to evaluate the effects of a mixture of 12 PCB congeners (CB18, 28, 70, 77, 99, 101, 118, 138, 153, 180, 187 and 202, each congener 0.5 mg/kg BW, i.p. administration) on serum TH levels in male dogs (Canis lupus familiaris) and male cats (Felis silvestris catus). In PCB-exposed dogs, the time courses of higher-chlorinated PCBs and L-thyroxine (T4)-like OH-PCBs (4-OH-CB107 and 4-OH-CB202) concentrations were unchanged or tended to increase, whereas those of lower-chlorinated PCBs and OH-PCBs tended to decrease after 24 h. In PCB-exposed cats, concentrations of PCBs increased until 6 h and then remained unchanged. The levels of lower-chlorinated OH-PCBs including 4′-OH-CB18 increased until 96 h and then decreased. In PCB-exposed dogs, free T4 concentrations were higher than those in the control group at 48 and 96 h after PCB administration and positively correlated with the levels of T4-like OH-PCBs, suggesting competitive binding of T4 and T4-like OH-PCBs to a TH transporter, transthyretin. Serum levels of total T4 and total 3,3′,5-triiodo-L-thyronine (T3) in PCB-exposed dogs were lower than in the control group at 24 and 48 h and negatively correlated with PCB concentrations, implying that PCB exposure enhanced TH excretion by increasing TH uptake and TH conjugation enzyme activities in the dog liver. In contrast, no obvious changes in TH levels were observed in PCB-exposed cats. This could be explained by the lower levels of T4-like OH-PCBs and lower hepatic conjugation enzyme activities in cats compared with dogs. Different effects on serum TH levels in PCB-exposed dogs and cats are likely to be attributable to species-specific PCB and TH metabolism.

There is concern that psychoactive drugs present in the aquatic environment could affect the behaviour of fish, and other organisms, adversely. There is considerable experimental support for this concern, although the literature is not consistent. To investigate why, fish were exposed to three concentrations of the synthetic opiate tramadol for 23-24 days, and their anxiolytic behaviour in a novel tank diving test was assessed both before and after exposure. The results were difficult to interpret. The positive control drug, the anti-depressant fluoxetine, produced the expected results: exposed fish explored the novel tank more, and swam more slowly while doing so. An initial statistical analysis of the results provided relatively weak support for the conclusion that both the low and high concentrations of tramadol affected fish behaviour, but no evidence that the intermediate concentration did. To gain further insight, UK and Japanese experts in ecotoxicology were asked for their independent opinions on the data for tramadol. These were highly valuable. For example, about half the experts replied that a low concentration of a chemical can cause effects that higher concentrations do not, although a similar number did not believe this was possible. Based both on the inconclusive effects of tramadol on the behaviour of the fish and the very varied opinions of experts on the correct interpretation of those inconclusive data, it is obvious that more research on the behavioural effects of tramadol, and probably all other psychoactive drugs, on aquatic organisms is required before any meaningful risk assessments can be conducted. The relevance of these findings may apply much more widely than just the environmental risk assessment of psychoactive drugs. They suggest that much more rigorous training of research scientists and regulators is probably required if consensus decisions are to be reached that adequately protect the environment from chemicals.

Brominated aromatic compounds are unintentionally generated during various thermal processes, including municipal solid waste incineration, electric-waste open burning, and secondary copper smelting. Copper (Cu) plays an important role in the formation of brominated aromatic compounds. In the present study, the thermochemical behaviors of Cu and Br in model samples, including copper bromide (CuBr2) and activated carbon, were studied using in situ X-ray absorption near-edge structure (XANES) and thermogravimetry. Quantification of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) was also conducted by gas chromatograph-high resolution mass spectrometer. Three key reactions were identified: (i) the reduction of CuBr2 to CuBr (room temperature to 300 °C), (ii) the generation of Br bonded with aromatic carbon (150-350 °C), and (iii) the oxidation of copper (>350 °C). Maximum amounts of PBDD/Fs were found in residual solid phase after heating at 300 °C. The analytical results indicated the direct bromination of aromatic carbon by the debromination of copper bromides (I, II) and that CuBr and CuO acted as catalysts in the oxidation of the carbon matrix. The bromination mechanisms revealed in this study are essential to the de novo formation of PBDD/Fs and other brominated aromatic compounds.

Although bioaccessibility testing is applied worldwide for appropriate chemical risk assessment, few studies have focused on the bioaccessibility of flame retardants (FRs), especially inhalation exposure. This study assessed inhalation exposure to FRs in indoor dust by workers at e-waste-dismantling workshops in northern Vietnam, by using modified simulated epithelial lung fluid (SELF) and artificial lysosomal fluid (ALF). The average mass concentrations of FRs were 130,000 ng/g for workplace dust (n = 3), 140,000 ng/g for floor dust (n = 3), and 74,000 ng/g for settled dust (n = 2), whereas the average bioaccessible concentrations of FRs were 1900, 1400, and 270 ng/g in the SELF condition and 2600, 770, and 490 ng/g in the ALF condition, respectively. Results clearly indicate that the bioaccessible concentrations of FRs are markedly lower than their mass concentrations. Tris(2-chloroethyl) phosphate (TCEP, ~19%), tris(2-chloroisopropyl) phosphate (TCIPP, ~35%), and tris(1,3-dichloroisopropyl) phosphate (TDCIPP, ~22%) showed comparably high bioaccessibility in both SELF and ALF conditions. In contrast, the bioaccessibility of tetrabromobisphenol A (TBBPA, ~20%) was high in the SELF condition, but not in the ALF condition. With regard to the test compounds' physicochemical properties, the inhalation bioaccessibility of FRs in both conditions increased as molecular weight or octanol–water partition coefficient decreased, and it decreased as water solubility decreased. Health risk assessment clearly indicated that the hazard quotient of FRs via inhalation exposure for workers in the e-waste-dismantling workshops was less than 1, suggesting that the inhalation exposure to FRs during indoor dismantling of e-waste at this site was negligible based on the current methodology of non-cancer health risk assessment used in this study.

The presence of antimicrobials, antimicrobial-resistant bacteria (ARB), and the associated antimicrobial resistance genes (ARGs) in the environment is a global health concern. In this study, the concentrations of 25 antimicrobials, the resistance of Escherichia coli (E. coli) strains in response to the selection pressure imposed by 15 antimicrobials, and enrichment of 20 ARGs in E. coli isolated from hospital wastewaters and surface waters were investigated from 2016 to 2018. In hospital wastewaters, clarithromycin was detected at the highest concentration followed by sulfamethoxazole and sulfapyridine. Approximately 80% of the E. coli isolates were resistant, while 14% of the isolates exhibited intermediate resistance against the tested antimicrobial agents. Approximately 61% of the examined isolates were categorized as multidrug-resistant bacteria. The overall abundance of phenotypes that were resistant toward drugs was in the following order: β-lactams, tetracycline, quinolones, sulfamethoxazole/trimethoprim, aminoglycosides, and chloramphenicol. The data showed that the E. coli isolates frequently harbored blaTEM, blaCTX-M, tetA, qnrS, and sul2. These results indicated that personal care products were significantly associated with the presence of several resistant phenotypes and resistance genes, implying their role in co-association with multidrug resistance. Statistical analysis also indicated a disparity specific to the site, treatment, and year in the data describing the prevalence of ARB and ARGs and their release into downstream waters. This study provides novel insights into the abundance of antimicrobial, ARB and ARGs in Sri Lanka, and could further offer invaluable information that can be integrated into global antimicrobial resistance databases.

The presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems has raised concern about their potential adverse effects on aquatic organisms. Considering the fact that the physiological/biological effects of PPCPs are triggered when their concentrations in the organism exceeds the respective threshold values, it is important to understand the bioconcentration and toxicokinetics of PPCPs in aquatic organisms. In the present study, we developed a convenient analytical method for the determination of 65 pharmaceuticals and 7 personal care products (log Kow = 0.14–6.04) in plasma and whole-body tissues of fish. The analytical method consists of ultrasound-assisted extraction in methanol/acetonitrile (1:1, v/v,) acidified with acetic acid-ammonium acetate buffer (pH 4), cleanup on a HybridSPE®-Phospholipid cartridge (zirconia-coated silica cartridge), and quantification with liquid chromatography-tandem mass spectrometry (LC–MS/MS). Acceptable accuracy (internal standard-corrected recovery: 70%–120%) and intra- and inter-day precision (coefficient of variation

The present study determined contamination levels of POPs, such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs), in oysters (Saccostrea mordax) collected throughout the seacoast of Okinawa, Japan and their geographic distribution. PCBs, DDTs, CHLs, PBDEs and HBCDs were detected in almost all the oyster samples analyzed and higher concentrations of PCBs, DDTs and CHLs were found in oysters from southwestern populated areas. On the other hand, HBCDs in oysters showed similar levels throughout Okinawa and the highest concentration in a northern rural site with less human and industrial activities, although oyster concentrations of PBDEs were relatively lower. When POPs in expanded polystyrene (EPS) buoys and polystyrene foam debris floated and drifted on coastal seawater were analyzed, extremely high concentrations of HBCDs were detected in some of these EPS buoys and polystyrene foam debris but other POPs were below the limit of detection in all the samples. To evaluate the specific exposure route of HBCDs for oysters, we further analyzed HBCD diastereomers, and PCB congeners by way of comparison, in seawater and sediment samples collected at an urban site and a rural site and estimated their biota (oyster)-sediment accumulation factors (BSAF) and bioaccumulation factors (BAF). Interestingly, the highest log BAF values were found for α-HBCD despite its lower log Kow than those of γ-HBCD and PCB congeners, although log BSAF values for HBCDs were lower than those for PCBs. Considering that α-HBCD was detected in a few polystyrene foam samples as the predominant diastereomer, oysters inhabiting the coastal region of Okinawa might be frequently exposed to micronized polystyrene foam particles containing HBCDs.

Triclosan (TCS), a commonly used antimicrobial compound, has recently been detected in the eggs of wild avian species. Exposure to TCS in rodents is known to interfere with thyroid hormone (TH), disrupt immune responses and cause liver disease. However, no attempt has been made to clarify the effects of TCS in avian species. The aim of this study is therefore to evaluate the toxic effects of in ovo exposure to TCS and explore the molecular mechanism by transcriptome analysis in the embryonic liver of a model avian species, chicken (Gallus gallus). Embryos were treated with graded concentration of TCS (0.1, 1 and 10 μg/g egg) at Hamburger Hamilton Stage (HHS) 1 (1st day), followed by 20 days of incubation to HHS 46. At the administration of 10 μg TCS/g egg, embryo mortality increased from 20% in control to 37% accompanied with 8% attenuation in tarsus length. While liver somatic index (LSI) in TCS treatments was enhanced, statistical difference was only observed at the treatment of 0.1 μg TCS/g egg in females. The up-regulation of several crucial differentially expressed genes (DEGs) in transcriptome analysis suggested that TCS induced xenobiotic metabolism (e.g. CYP2C23a, CYP2C45 and CYP3A37 in males; CYP2C45 in females) and activated the thyroid hormone receptor (THR) - mediated downstream signaling (e.g. THRSPB and DIO2 in males; THRSPB in females). In females, TCS may further activate the lipogenesis signaling (e.g. ACSL5, ELOVL2) and repress the lipolysis signaling (e.g. ABHD5, ACAT2). A battery of enriched transcription factors in relation to these TCS-induced signaling and phenotypes were found, including activated SREBF1, PPARa, LXRa, and LXRb in males and activated GLI2 in females; COUP-TFII was predicted to be suppressed in both genders. Finally, we developed adverse outcome pathways (AOPs) that provide insights into the molecular mechanisms underlying the alteration of phenotypes.

Recent species-extrapolation approaches to the prediction of the potential effects of pharmaceuticals present in the environment on wild fish are based on the assumption that pharmacokinetics and metabolism in humans and fish are comparable. To test this hypothesis, we exposed fathead minnows to the opiate pro-drug tramadol and examined uptake from the water into the blood and brain and the metabolism of the drug into its main metabolites. We found that plasma concentrations could be predicted reasonably accurately based on the lipophilicity of the drug once the pH of the water was taken into account. The concentrations of the drug and its main metabolites were higher in the brain than in the plasma, and the observed brain and plasma concentration ratios were within the range of values reported in mammalian species. This fish species was able to metabolize the pro-drug tramadol into the highly active metabolite O-desmethyl tramadol and the inactive metabolite N-desmethyl tramadol in a similar manner to that of mammals. However, we found that concentration ratios of O-desmethyl tramadol to tramadol were lower in the fish than values in most humans administered the drug. Our pharmacokinetic data of tramadol in fish help bridge the gap between widely available mammalian pharmacological data and potential effects on aquatic organisms and highlight the importance of understanding drug uptake and metabolism in fish to enable the full implementation of predictive toxicology approaches.

A fish plasma model (FPM) has been proposed as a screening technique to prioritize potential hazardous pharmaceuticals to wild fish. However, this approach does not account for inter- or intraspecies variability of pharmacokinetic and pharmacodynamic parameters. The present study elucidated the uptake potency (from ambient water), tissue distribution, and biological risk of 20 pharmaceutical and personal care product (PPCP) residues in wild cyprinoid fish inhabiting treated-wastewater-impacted streams. In order to clarify the uncertainty of the FPM for PPCPs, we compared the plasma bioaccumulation factor in the field (BAFplasma = measured fish plasma/ambient water concentration ratio) with the predicted plasma bioconcentration factor (BCFplasma = fish plasma predicted by use of theoretical partition coefficients/ambient water concentration ratio) in the actual environment. As a result, the measured maximum BAFplasma of inflammatory agents was up to 17 times higher than theoretical BCFplasma values, leading to possible underestimation of toxicological risk on wild fish. When the tissue-blood partition coefficients (tissue/blood concentration ratios) of PPCPs were estimated, higher transportability into tissues, especially the brain, was found for psychotropic agents, but brain/plasma ratios widely varied among individual fish (up to 28-fold). In the present study, we provide a valuable data set on the intraspecies variability of PPCP pharmacokinetics, and our results emphasize the importance of determining PPCP concentrations in possible target organs as well as in the blood to assess the risk of PPCPs on wild fish.