Fanti Values Research Articles

Dechlorane plus in dust, hair and urine: Exposure, excretion and level change

Dechlorane plus (DP) has been detected in a variety of environmental media and in human. Measurement of DPs in hair, urine, and house dust across different habitats allows for the assessment of short-term spatial changes in human exposure to DPs, as well as their excretion in urine. This offers a significant reference point for further research on the behavior of persistent pollutants within organisms. We measured and analyzed the concentrations of DP in the hair and urine of 32 students from a university in Beijing during school and home phases, and in indoor dust from dormitories and some home environments. The results indicated that the concentrations of DP in three types of samples were higher during the home phase compared to the school phase. We compared the fanti values and identified selective enrichment of syn-DP in hair, along with selective excretion of syn-DP in urine. Utilizing molecular docking technique, we simulated the binding effect between DP and the Megalin protein. The results demonstrated that the binding energy of anti-DP to Megalin was higher than that of syn-DP, suggesting that anti-DP has a greater propensity to bind to Megalin and be reabsorbed. This results in higher levels of syn-DP excretion in urine. Finally, we categorized students based on their participation in the organic exposure experiment and their BMI. The results indicated that the concentrations of DP in hair and urine were higher in the exposed group compared to the non-exposed group during the school year. After excluding the effect of exposure, habitat changes were more likely to affect the accumulation and excretion of DP in normal-weight students (BMI ≤24 kg/m2, n = 28), while overweight students (BMI >24 kg/m2, n = 4) were less affected by the effect of habitat because of their higher body fat percentage and their greater ability to accumulate DP.

Historical Occurrence and Composition of Novel Brominated Flame Retardants and Dechlorane Plus in Sediments from an Electronic Waste Recycling Site in South China.

Novel brominated flame retardants (NBFRs) and dechlorane plus (DP) have been widely used as alternatives to traditional BFRs. However, little is known about the temporal trends of NBFR and DP pollution in e-waste recycling sites. In the current study, three composite sediment cores were collected from an e-waste-polluted pond located in a typical e-waste recycling site in South China to investigate the historical occurrence and composition of NBFRs and DP. The NBFRs and DP were detected in all layers of the sediment cores with concentration ranges of 5.71~180,895 and 4.95~109,847 ng/g dw, respectively. Except for 2,3,5,6-tetrabromo-p-xylene (pTBX) and 2,3,4,5,6-pentabromoethylbenzene (PBEB), all the NBFR compounds and DP showed a clear increasing trend from the bottom to top layers. These results implied the long-term and severe contamination of NBFRs and DP. Decabromodiphenyl ethane (DBDPE) was the most abundant NBFR with the contribution proportions of 58 ± 15%, 73 ± 15%, and 71 ± 18% in three sediment cores, followed by 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) and pentabromobenzene (HBB). The ratios of BTBPE/Octa-BDEs and DBDPE/Deca-BDEs varied from 0.12 to 60 and from 0.03 to 0.49, respectively, which had no clear increase trends with a decrease in sediment depth. As for DP, the fanti values (the concentration ratios of anti-DP to the sum of anti-DP and syn-DP) in sediment cores ranged from 0.41 to 0.83, almost falling in the range of those in DP technical products, suggesting that DP degradation did not occur in sediment cores. The environmental burdens of DBDPE, BTBPE, HBB, PBT, PBEB, pTBX, and DP were estimated to be 34.0, 5.67, 10.1, 0.02, 0.02, 0.01, and 34.8 kg, respectively. This work provides the first insight into the historical contamination status of NBFRs and DP in the sediments of an e-waste recycling site.

Dechlorane Plus in environmental samples and human serum samples from new and old electronic waste dismantling areas in East China: Levels, composition profiles, and human exposure

The global presence of Dechlorane Plus (DP) in environmental and human samples highlights the need for further research into its ecological risks and health effects. This study determined DP concentrations in soil and air samples from an old electronic waste dismantling area (Fengjiang) and a new electronic waste dismantling area (Binhai) in Taizhou City, China. Both syn-DP and anti-DP isomers were found in all soil and air samples. The median concentrations of DP in soil and air were 90.5 ng/g and 48.4 pg/m3 in Fengjiang, and 6.69 ng/g and 28.8 pg/m3 in Binhai. DP were widespread in the local environment, and in general at moderate levels compared with reports from other electronic waste dismantling areas. The analysis of DP isomer profiles in different seasons and the calculation of related fugacity fraction showed that anti-DP perhaps easier than syn-DP to migrate from soil to air in summer. DP concentrations in serum of residents from Fengjiang (median 9.74 ng/g) were significantly higher than those from Huangyan (common control area, median 2.77 ng/g; p < 0.01), while the fanti value showed that Fengjiang was significantly lower than Huangyan (p < 0.05). This revealed that DP exposure levels in serum perhaps one of the crucial factors influencing fanti value. Moreover, DP concentrations in serum showed an increasing trend with increasing body mass index (BMI) or age. However, the relationship between DP and sex was not observed. The fanti values of serum samples were higher than those in soil and air samples, suggested that DP perhaps stereo-selectively absorbed into the body or stereo-selectively metabolised.

Current pollution status, spatial features, and health risks of legacy and emerging halogenated flame retardants in agricultural soils across China

Soil is a major reservoir and a secondary source of semi-volatile organic chemicals, while studies on the pollution status of halogenated flame retardants (HFRs) in agricultural soils are limited. In this study, a total of twenty-five chemicals including novel brominated flame retardants (NBFRs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DPs) was analyzed in the agricultural soils across China to investigate the occurrence, spatial distribution, potential sources, influencing factors and their associated human health risks. The results showed that BDE-209 (125–130,183 pg/g, dry weight, d.w.) was the most abundant flame retardant of PBDEs, followed by decabromodiphenyl ethane (DBDPE) (9.27–22,864 pg/g, d.w.). Meanwhile, the DPs (anti-DP plus syn-DP) were in the range of ND-1229 pg/g (d.w.), and the range of fanti values (the concentration of anti-DP divided by the sum of the concentrations of two isomers) in this study greatly matched those of commercial products, suggesting the effect of proximity to the source region. The higher levels of HFRs were found in Eastern and Southern regions of China. Spatial distribution implied that e-waste recycling activities and plastic processing have shown more importance in releasing legacy flame retardants (FRs) into the environment than the manufacturing process, while all are important for novel FRs. Correlation analysis between influencing factors and HFRs indicated that the distribution of most pollutants was more affected by anthropogenic source factors than environmental factors. The results of the principal component analysis demonstrated that deca-BDE and its alternative products were the major contributors to the sources of HFRs pollution. Human health risks assessment via oral intake and dermal contact pathways presented that the selected pollutants posed a no-carcinogenic risk to children and adults. It is worth noting that supervision of the disposal process of the NBFRs should be strengthened in the future.

Halogenated flame retardants in surface sediments from fourteen estuaries, South China

A total of seventy surface sediments were collected from fourteen estuaries of South China to investigate the distribution of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE) and dechlorane plus (DP). The concentrations of Σ16PBDEs, DBDPE, BTBPE and DP in estuarine sediments ranged from 0.39 to 81.2, 0.18 to 49.9, not detected to 0.62, and 0.025 to 1.66 ng/g dry weight, respectively. Significant differences for levels of Σ16PBDEs, DBDPE, BTBPE and DP were found among the sediments from fourteen estuaries. Sediments from the Pearl River Estuary had the highest concentrations of Σ16PBDEs, DBDPE and DP. PBDEs and DBDPE were the main halogenated flame retardants in estuarine sediments. BDE 209 was predominant congener of PBDEs with an average contribution of 88.1% to the total PBDEs. 32.9% sediment samples from South China had fanti values lower than 0.65, suggesting that stereoselective enrichment of syn-DP occurred in estuarine sediments.

Dechlorane Plus Biomagnification and Transmission through Prairie Food Webs in Inner Mongolia, China.

Dechlorane Plus (DP) is found widely in the environment. It is important to study DP enrichment and biomagnification in terrestrial ecosystems to improve our understanding of the possible effects of DP on the environment and human health. A total of 90 samples, including plant and animal tissues, were collected from Xilingol Prairie in Inner Mongolia, China. The DP concentrations in different species were assessed, and transmission of DP through food webs containing ectotherms and endotherms was assessed. The compound was detected in the biotic samples (plant; range 0.133-0.422 ng/g dry wt), in animal muscle (range: not dected-5.70 ng/g lipid wt), and in animal hair (range: not dected-2.03 ng/g dry wt), indicating that DP is present in remote environments such as Xilingol Prairie. These findings suggest that DP can undergo long-distance transport in the environment. Biomagnification factors (ectotherms: range 0.146-88.0, endotherms: range 0.866-17.2) and anti-DP/total DP concentration ratios (fanti values of 0.412-0.787) for the prairie animals were calculated. Ectotherms were found to selectively enrich syn-DP, and stereoselective enrichment increased moving up the food web. Lower-trophic-level endotherms strongly stereoselectively enriched syn-DP, and higher-trophic-level endotherms stereoselectively enriched anti-DP. Environ Toxicol Chem 2021;40:413-421. © 2020 SETAC.

Polybrominated diphenyl ethers, decabromodiphenyl ethane and dechlorane plus in aquatic products from the Yellow River Delta, China

Aquatic biota including fish, shrimp and bivalves were collected from the Yellow River Delta (YRD), China to investigate the levels, composition profile and dietary exposure of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and dechlorane plus (DP). The concentrations of PBDEs, DBDPE and DP in the organisms ranged from 5.3 to 149, not detected (nd) - 49, and 0.5–29 ng/g lipid weight, respectively. Higher levels of PBDEs and DP were found in mullet (Liza haematocheila).PBDEs were the major pollutants and BDE 209 was the predominant congener of PBDEs suggesting the great production and application of deca-BDE in YRD. The average fanti values for different species were similar to or a little lower than that of the commercial DP, suggesting syn-DP might be selectively accumulated by the organisms. The estimated daily intake values of HFRs suggested consuming fish was the main pathway for the exposure of halogenated flame retardants.

Alternative halogenated flame retardants (AHFRs) in green mussels from the south China sea

Restrictions of legacy brominated flame retardants, such as polybrominated diphenyl ether (PBDE) and polybrominated biphenyl (PBB), have resulted in increased usage of alternative halogenated flame retardants (AHFRs). Consequently, AHFRs contamination has caused a major concern in the scientific community. However, there is limited information on their presence in marine mussels. In this study, we investigated the occurrence and distribution of polybrominated biphenyls (PBBs), AHFRs and dehalogenated products in green mussels collected from 22 locations in the northern South China Sea (SCS). Our results revealed that ∑AHFRs were ubiquitous in green mussels with concentrations in the range of 1.08–7.71 ng/g lipid weight (lw). Among target AHFRs, hexabromobenzene (HBB), decabromodiphenyl (DBDPE) and dechlorane plus (DP) were predominant with their mean values of 1.19, 1.00 and 0.82 ng/g lw, respectively. There were negligible stereoisomer enrichments of DP in green mussels based on fanti values, indicating a limited bioaccumulation and metabolism of DP in green mussels. In comparison with other locations, concentrations of the AHFRs in green mussels determined here were at moderate levels. Additionally, there were significant linear relationships between some AHFRs (e.g., HBB and PBEB), suggesting their similar commercial applications and sources in the environment. The estimated daily intakes of AHFRs through consumption of green mussels by the local population in South China were 0.05–0.14 ng/kg body weight/day and 0.17–0.44 ng/kg body weight/day based on the mean and 95th concentrations, respectively. To the best of our knowledge, the present study is the first to report AHFRs and dehalogenated products in green mussels.

Pine needles as biomonitors of polybrominated diphenyl ethers and emerging flame retardants in the atmosphere of Shanghai, China: occurrence, spatial distributions, and possible sources.

In this study, pine needles were used as biomonitors to investigate the levels, spatial distributions, and possible sources of polybrominated diphenyl ethers (PBDEs) and four emerging halogenated flame retardants (HFRs) in the atmosphere of Shanghai, China. The four emerging HFRs were hexabromocyclododecane (HBCD), decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and dechlorane plus (DP), with the first 3 HFRs being non-polybrominated diphenyl ether brominated flame retardants (non-PBDE BFRs). The total concentrations ranged from 3.71 to 4020ngg-1 dry weight (dw) for 52 PBDE congeners (Σ52BDEs), < MDL (method detection limit) to 15.2ngg-1 dw for three non-PBDE BFRs (Σ3non-PBDE BFRs), and 0.815 to 1090pgg-1 dw for two DP isomers (ΣDP), respectively. High levels of PBDEs, three non-PBDE BFRs, and DP were found in pine needles from suburbs and Pudong, which was a consequence of industrial activities. The fraction of anti-DP isomer (fanti) in pine needles ranged from 0.515 to 0.939 with a mean value of 0.721, and most of the fanti values were consistent with those of technical DP formulations. Principal component analysis-multiple linear regression (PCA-MLR) model identified four sources of PBDEs in pine needles with the quantified contributions: degradation of technical PBDE formulations (49.5%), technical deca-BDE (6.9%), technical penta-BDE (25.1%), and technical octa-BDE (18.5%). These findings are expected to help understand the pollution level, fate, and possible sources of HFRs in the atmosphere of Shanghai and provide a basis for air pollution control and management in Shanghai.

Distribution Characteristics and Source of Dechloranes in Soil and Lichen of the Fildes Peninsula (Antarctica).

Dechloranes (Decs) have been widely found in the environment, even in the Tibetan Plateau and remote polar regions. However, the understanding of their regional distribution characteristics in polar regions is limited. To study the long-range atmospheric transport and fates of these emerging contaminants, Decs were analyzed in soil and lichen from the Fildes Peninsula in Antarctica. The concentrations of five Decs in soil and lichen ranged from 141.46 to 838.47 pg/g dw and 237.04 to 3599.18 pg/g dw, respectively. The mean fractions of anti-Dechlorane Plus (DP) (fanti) values estimated in the current soils (0.37) and lichen (0.24) were lower than those of commercial products (fanti = 0.64–0.80), which confirms that long-range atmospheric transport is a main source of DP, and the DP burdens could be driven by the accumulation of syn-DP. The average ΣDP concentration in soil in the coastal area was higher than that in the inland area and Ardley Island, while in lichen, the average DP concentration at the Ardley Island site was approximately three-fold higher than that in the coastal area and inland areas. This indicates that the distribution of DP was influenced by anthropogenic interference and animal activities in the Fildes Peninsula. The spatial variation of fanti of the three regions was clearer in soil than that in lichen. The fanti values were negatively correlated with DP concentrations in soil, suggesting that DP concentration levels play an important role in determining the isomeric composition of DP in the soil.

Dechlorane plus (DP) in indoor and outdoor air of an urban city in South China: Implications for sources and human inhalation exposure

ABSTRACTDechlorane Plus (DP) is a chemical of emerging concern due to the restrictions on brominated flame retardant formulations. However, very little information is known about the occurrence of DP in indoor and outdoor air and its associated health risk to the exposed human population. In this study, we examined the concentrations and isomer profiles of DP in archived air samples collected from 14 homes, 6 offices, and 10 public microenvironments in Guangzhou, China in 2004–2005. The average (median) value of atmospheric ΣDP (sum of anti-DP and syn-DP) concentration in the three indoor air was 5.73 ± 5.33 (3.62) for offices, 8.08 ± 5.17 (6.87) for homes, and 57.27 ± 83.08 (32.58) pg/m3 for public microenvironments, respectively. ΣDP concentration was significantly higher in the public microenvironments than those in homes and offices. The arithmetic mean and median concentrations of ΣDP in outdoor air were 36.00 and 28.76 pg/m3, respectively. Spatially and temporally consistent indoor and outdoor samples comparison suggested that outdoor air might be a relevant source of DP for indoor air. Average anti-DP fractional abundance (fanti = 0.65 ± 0.04) in all outdoor samples was similar to those reported in other studies and indistinguishable from that of the commercial mixture (fanti = 0.65). In contrast, a relatively large variation of fanti values was found in the indoor samples, suggesting a complex degradation process of DP existing in these microenvironments. The calculated average daily doses of ΣDP were in the range of 0.38–2.21 ng/day for people intake through air inhalation, which was in the same order of magnitude compared with other exposure pathways for the general publics.

Stereoselective bioaccumulation of syn- and anti-Dechlorane plus isomers in different tissues of common carp (Cyprinus carpio)

Common carps (Cyprinus carpio) were exposed to syn- and anti-Dechlorane Plus (DP) isomers to investigate absorption, tissue distribution, and stereoselective bioaccumulation of DP isomers. The absorption efficiencies of anti-DP in the gastrointestinal system were higher than those of syn-DP. A linear accumulation was found for both isomers in all fish tissues except for serum; and the liver and gill exhibited the highest and lowest DP assimilation efficiency, respectively. The elimination of DP isomers in all tissues followed first-order kinetics, with the fastest depuration rate occurring in the liver and serum. The biomagnification factors (BMFs) of both isomers were less than one in all tissues, except for serum. Anti-DP was preferably accumulated in the liver, gill, and serum, whereas syn-DP was selectively accumulated in the carcass and gastrointestinal tract. As a whole, fish did not show selective accumulation of the syn- or anti-DP isomer in the uptake stage, whereas a selective accumulation of syn-DP in fish was observed during the depuration period, which could be due to a selective excretion of anti-DP. Metabolism cannot be ruled out as a possible reason considering the high fanti values and the high elimination rate of DPs in the liver.

Habitat- and species-dependent accumulation of organohalogen pollutants in home-produced eggs from an electronic waste recycling site in South China: Levels, profiles, and human dietary exposure

Organohalogen pollutants (OHPs) including chlorinated paraffins (CPs), polybrominated diphenyl ethers (PBDEs) and other halogenated flame retardants (OHFRs) (dechlorane plus (DP), decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), hexabromocyclododecanes (HBCDs) and tetrabromobisphenol A (TBBPA)) originating from an e-waste recycling area in Guiyu, southern China were investigated in chicken and goose eggs. As expected, OHP concentrations were higher in chicken eggs collected from the location (site 1) approaching the e-waste recycling center than from the location (site 2) far from the e-waste recycling center. Also, much higher OHP levels were observed in goose eggs foraging in residential area (site 2) than that in agricultural area (site 1), suggesting a clear habitat dependent OHP bioaccumulation pattern both concerning distance from e-waste activities and type of foraging habitat. Goose eggs exhibited higher short chain chlorinated paraffins (SCCPs) concentrations but lower PBDE and OHFR levels than chicken eggs. The proportion of high brominated PBDEs (hepta-to deca-BDEs) was lower in goose eggs than that in chicken eggs and showed a clear decrease from site 1 to site 2. DP isomeric composition fanti values (the ratio of the anti-DP to the sum of the anti- and syn-DP) in goose eggs were significantly lower than those in chicken eggs (p < 0.001). These differences are likely a reflection of factors such as the species-specific differences in habitat preference and the differing environmental behaviors of the pollutants owing to their inherent properties (such as solubility and vapor pressure). Our findings suggested a high dietary intake of OHPs via home-produced eggs. For BDE99 there is a potential health concern with respect to the current dietary exposure via eggs.

Concentrations and distributions of Dechlorane Plus in environmental samples around a Dechlorane Plus manufacturing plant in East China

A comprehensive investigation into the occurrence of Dechlorane Plus (DP) in environmental samples around a DP manufacturing plant in East China was performed. The total syn-DP and anti-DP concentrations found in the soil, sediment, active air, and passive air samples were 0.50–2,315pg/g dry weight (dw), 0.32–20.5ng/g dw, 5.52–3,332pg/m3, and 1.00–4,560pg/m3, respectively. There were consistent trends in the spatial distributions of DP in the soil and air samples, with the DP concentrations decreasing dramatically as the distance from the plant increased. The mean anti-DP isomer fractional abundances (fanti) in the soil, sediment, active air, and passive air samples were 0.67, 0.68, 0.70, and 0.64, respectively. These fanti values were consistent with the fanti value for the technical DP produced in the DP manufacturing plant (0.68), meaning that the DP had been released during the local DP production activities.

Accumulation of Dechlorane Plus flame retardant in terrestrial passerines from a nature reserve in South China: The influences of biological and chemical variables

Although a number of studies have addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, few data are available on terrestrial organisms. This study examined the presence of DP isomers in the muscle tissue of seven terrestrial resident passerine species, i.e., the great tit (Parus major), the oriental magpie-robin (Copsychus saularis), the red-whiskered bulbul (Pycnonotus jocosus), the light-vented bulbul (Pycnonotus sinensis), the streak-breasted scimitar babbler (Pomatorhinus ruficollis), the long-tailed shrike (Lanius schach), and the orange-headed thrush (Zoothera citrina), from a national nature reserve located in South China. The ∑DP (sum of syn-DP and anti-DP) concentrations ranged from 1.2 to 104ng/g lipid weight, with significantly higher levels in insectivorous birds than in omnivorous birds. The overall exposure to DP isomers of the current passerines may be attributed to the intensive release of this pollutant from electronic waste recycling sites and industrial zones in the vicinity of the nature reserve. Species-specific DP isomeric profiles were also found, with significantly greater fanti values (the isomer fractions of anti-DP) in the red-whiskered bulbul and the oriental magpie-robin. Additionally, the fanti values were significantly negatively correlated to ∑DP concentrations for the individual bird samples, suggesting the influence of DP concentrations on the isomeric profiles.

Sources, gastrointestinal absorption and stereo-selective and tissue-specific accumulation of Dechlorane Plus (DP) in chicken

Dechlorane Plus (DP) isomers, along with two dechlorinated metabolites were measured in environmental matrices, chyme and digestive tract contents and tissues of chicken from an e-waste recycling site located in South China. Soil is proved to be the main source of DP in chicken rather than food because soil contributes more than 94% of total DP in chyme. In the gastrointestinal tract absorption processes, no selective absorption was observed for DP isomers during the ingestion processes. The tissue distribution of DP isomers in chicken exhibits complicated characteristics. The lipid contents in tissues are the main factors in the tissue distribution of DP, while the different blood perfusion state and the different tissue functions also seem to influence the tissue distribution of DP. The fat, brain, and liver exhibit higher fanti values (0.65, 0.64, and 0.64) than the other tissues (0.54–0.59). The elevated fanti values of DP from the contamination source (0.52 in soil) to chicken suggest stereoselective bioaccumulation of anti-DP in chicken. The similar ratios of anti-Cl11-DP to anti-DP between soil and chicken imply that anti-Cl11-DP mainly derives from the uptake from environment rather than in vivo dechlorination.

Gastrointestinal absorption, dynamic tissue-specific accumulation, and isomer composition of dechlorane plus and related analogs in common carp by dietary exposure

Dechlorane plus (DP) is a high-productive volume substance which had been identified as ubiquitous pollutant and has been widely detected in biota. In the present study, common carp (Cyprinus carpio) was exposed to known amounts of commercial DP-25 under laboratory conditions. The gastrointestinal absorption and tissue-specific bioaccumulation of DP and its dechlorinated analogs in common carp were investigated. The higher absorption efficiencies but lower assimilation efficiencies of anti-isomers indicated stereoselective metabolism of anti-isomers in fish. Linear uptake curves were seen in serum and muscle, but the depuration curves for all the four tissues (muscle, serum, liver and gonad) did not follow the first-order kinetics. The liver exhibited a high affinity for anti-isomers during the experiment. Other tissues, such as serum, muscle, and gonad, showed a selective accumulation of syn-DP in the early stages of the experiment, particularly the serum. However, the deviation of fanti between different tissues disappeared at late stages of the experiment, and the fanti values in all tissues were close to that in commercial mixtures. Our results suggest that the bioaccumulation of DP is a complex and multi-factorial process.

Accumulation and effects of 90‐day oral exposure to Dechlorane Plus in quail (Coturnix coturnix)

While a number of studies have addressed bioaccumulation of the flame retardant Dechlorane Plus (DP), little information is available regarding the adverse effects of DP on animals, especially on bird species. In the present study, male common quails (Coturnix coturnix) were consecutively exposed to commercial DP-25 by gavage for 90 d at 1-mg/kg/d, 10-mg/kg/d, and 100-mg/kg/d dosages. Concentrations of DP isomers in liver, muscle, and serum were determined after exposure. Liver enzyme activity involved in xenobiotic biotransformation processes and oxidative stress was measured, as well as glutathione and maleic dialdehyde content. The results showed that DP was more prone to accumulate in the liver than in muscle and serum in all exposed groups. In tested tissues, syn-DP dominated in the high-exposure groups (10 and 100 mg/kg/d), whereas anti-DP tended to accumulate in the low-exposure group (1 mg/kg/d). The concentration ratios of anti-DP to total DP (fanti values) in the tissues examined were close to commercial DP in the low-exposure group; however, the fanti values were significantly decreased in the high-exposure groups. Enzyme activity of 7-pentoxyresorufin-O-demethylase (PROD) decreased significantly in all exposed groups compared with the control group, whereas activity of erythromycin N-demethylase (ERND) and the antioxidant enzyme catalase significantly increased in high-exposure groups. The results implied that DP exposure levels influenced isomeric compositions in organs and that DP exposure altered hepatic alkoxyresorufin O-dealkylase (AROD) activity and contributed to the biological effects of DP.

Dechlorane Plus flame retardant in kingfishers (Alcedo atthis) from an electronic waste recycling site and a reference site, South China: Influence of residue levels on the isomeric composition

Dechlorane Plus (DP) isomers were examined in common kingfishers (Alcedo atthis) and their prey fishes collected from an electronic waste (e-waste) recycling site and a reference site in South China, to investigate the possible influence of DP residue levels on the isomeric compositions. ∑DP (sum of syn-DP and anti-DP) concentrations in kingfishers from the e-waste recycling site ranged from 29 to 150 (median of 58) ng/g lipid weight (lw), which were one order of magnitude greater than those from the reference site (median = 3.9 ng/g lw). The isomer fractions of anti-DP (fanti) in kingfishers from the e-waste recycling site (mean of 0.65) were significantly smaller than those from the reference site (0.76). Additionally, the fanti values were negatively correlated to logarithm of ∑DP concentrations in the kingfishers (r2 = 0.41, p < 0.0001). These results suggested that DP residue levels could influence its isomeric composition in the piscivorous bird.

Accumulation pattern of Dechlorane Plus and associated biological effects on rats after 90 d of exposure

Recent studies have indicated that Dechlorane Plus (DP) is widespread in the environments. However, different isomer-specific enrichment pattern of syn-DP and anti-DP was reported in biological samples from the field. In this study, Sprague–Dawley rats were consecutively exposed to commercial DP 25 by gavage for 90d at different doses (0, 1, 10, and 100mgkg−1d−1) to investigate the accumulation pattern of syn-DP and anti-DP in liver, muscle, and serum of rats. The possible biological effects of DP on rats were also examined. Results showed that DP preferentially accumulated in the liver rather than in muscle at all exposure levels. No significant stereoselectivity of anti-DP or syn-DP in tissues was observed in the low DP exposure groups (0 and 1mgkg−1d−1) with fanti values (defined as the concentration of the anti-DP divided by the sum of concentrations of anti- and syn-DP) ranging from 0.74 to 0.78. However, fanti values reduced (fanti ranged from 0.26 to 0.30) significantly in the high DP exposure groups (10 and 100mgkg−1d−1) and syn-DP was predominant in all tissues. Biochemical parameters in serum, the mRNA expression levels of certain enzymes and their activities in liver were detected. There was no observable-effect in histopathology and death during the experiment, although the mRNA expression levels of some genes in the low dosage group decreased significantly and enzyme activity of CYP 2B2 increased.