Debromination of polybrominated diphenyl ether-99 (BDE-99) in carp (Cyprinus carpio) microflora and microsomes

Based on previous findings in dietary studies with carp (Cyprinus carpio), we investigated the mechanism of 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) debromination to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) using liver and intestinal components. In vitro aerobic and anaerobic experiments tested the ability of carp intestinal microflora to debrominate BDE-99. No debromination of BDE-99 to BDE-47 was observed in microfloral samples; therefore, carp enzymatic pathways were assessed for debromination ability. After sixty-min incubation, intestine and liver microsomes exhibited 83+/-34% and 106+/-18% conversions, respectively, of BDE-99 to BDE-47; with no significant (p>0.05) difference between organ debromination capabilities. Microsomal incubations with BDE-99, enzyme cofactors and competing substrates assessed the potential mechanisms of debromination. The presence of NADPH in the microsomal assay did not significantly (p>0.05) affect BDE-99 debromination, which suggest that cytochrome P450 enzymes are not the main debrominating pathway for BDE-99. Co-incubation of BDE-99 spiked microsomes with reverse thyronine (rT3) significantly (p<0.05) decreased the debromination capacity of intestinal microsomes indicating the potential of catalytic mediation via thyroid hormone deiodinases. The significant findings of this study are that intestinal microflora are not responsible for BDE-99 debromination, however, it is an endogenous process which occurs with approximately equal activity in intestine and liver microsomes and it can be inhibited by rT3.     

一株五溴联苯醚(BDE-99)降解菌的分离、鉴定及降解特性

采用梯度压力驯化法从高海拔地区土壤样品中分离到1株能以BDE-99作为碳源生长的细菌菌株,命名为BHS-4,通过生理生化及对16S rDNA扩增,T/A克隆后测序鉴定,并进一步分析初始pH、温度、碳源、细胞表胞疏水性（MATH法）及共存重金属离子对菌株降解效果的影响。结果表明：菌株BHS-4与产碱杆菌属Alcaligenes cupidus同源性为99%。菌株降解BDE-99最适pH和温度分别为8.0、20 ℃,经11 d培养后,对浓度0.4 mg·L-1的BDE-99,降解率达86.1%,在15~20 ℃范围具有较高降解率。降解特性研究结果显示,乳糖、麦芽糖和葡萄糖的添加促进了BHS-4对BDE-99的降解,而淀粉和乙酸钠添加对降解率产生了显著抑制作用（P4NO3的添加,使细胞表面疏水率（CSH）增加了49.5%,CSH与降解率呈极显著正相关（r=0.99, P2+、Zn2+在0.1~0.3 mg·L-1浓度下促进BDE-99降解;Cr6+在0.1~0.6 mg·L-1范围内对降解作用影响表现为先抑制、再促进、最后抑制。菌株BHS-4能在较低温度下对BDE-99进行高效降解且对Cu2+、Zn2+、Cr6+具有一定的耐性,可应用于低温地区BDE-99的生物处理,同时可为进一步研究低温条件下BDE-99生物降解的代谢途径和机理提供一定的基础资料。     

Oxidative transformation of polybrominated diphenyl ether congeners (PBDEs) and of hydroxylated PBDEs (OH-PBDEs)

BACKGROUND, AIM, AND SCOPE: The historical and widespread use of polybrominated diphenyl ethers (PBDEs) as flame retardants in consumer products worldwide has caused PBDEs to now be regarded as pervasive environmental contaminants. Most recently, hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have emerged as environmentally relevant due to reports of their natural production and metabolism. An important parameter for assessing the environmental impact of a chemical substance is persistence. By formulating the concept that persistence is the result of the substance's physicochemical properties and chemical reactivity, Green and Bergman have proposed a new methodology to determine the inherent persistence of a chemical. If persistence could be predicted by straightforward methods, substances with this quality could be screened out before large-scale production/manufacturing begins. To provide data to implement this concept, we have developed new methodologies to study chemical transformations through photolysis; hydrolysis, substitution, and elimination; and via oxidation. This study has focused on adapting an oxidative reaction method to be applicable to non-water soluble organic pollutants. MATERIALS AND METHODS: PBDEs and one MeO-PBDE were dissolved in tetrahydrofuran/methanol and then diluted in alkaline water. The OH-PBDEs were dissolved in alkaline water prior to reaction. The oxidation degradation reaction was performed at 50 degrees C using potassium permanganate as described elsewhere. The pH was maintained at 7.6 with disodium hydrogen phosphate and barium hydrogen phosphate, the latter also serving as a trapping agent for manganate ions. The oxidation reactions were monitored by high-performance liquid chromatography and reaction rates were calculated. RESULTS: The OH-PBDEs have very fast oxidative transformation rates compared to the PBDEs. The reaction rates seem to be primarily dependent on substitution pattern of the pi-electron-donating bromine substituents and of bromine content. There are indications that further reactions of OH-PBDEs, e.g., methylation to the MeO-PBDEs, decrease the oxidation rates, and thereby generate more persistent substances. DISCUSSION: The resistance of PBDEs to oxidation, a major degradation pathway in air, should be further investigated, since these compounds do undergo long range transport. With slight modifications, the original method has been adapted to include a larger variety of chemical substances, and preliminary data are now available on the oxidative transformation rates for PBDEs and of OH-PBDEs. CONCLUSIONS: The original oxidation degradation method can now include non-water soluble compounds. This modification, using low concentrations of test chemicals, allows us to measure oxidative transformation rates, for some of the lower brominated DEs, data that can be used to assess their persistence in future model calculations. Oxidative transformation rates for PBDEs are slow compared to those for the OH-PBDEs. This suggests that OH-PBDEs, when released into the environment, undergo faster oxidative metabolism and excretion than the PBDEs. RECOMMENDATIONS AND PERSPECTIVES: To evaluate the modified method, more degradation reactions with non-water soluble compounds should be investigated. Recent studies show that OH-PBDEs are present in rats and in humans and, because of their activity as endocrine disruptors, determining their subsequent environmental fate is of importance. The resistance of PBDEs to oxidative degradation should be acknowledged as of possible future concern. Several other compound classes (such as polychlorinated biphenyls (PCBs), hydroxylated polychlorinated biphenyls (OH-PCBs), and pharmaceuticals) need to be subjected to this screening method to increase the database of transformation rates that can be used with this model.     

Tissue distribution of 2,2',4,4'-tetrabromo[14C]diphenyl ether ([14C]-PBDE 47) in pike (Esox lucius) after dietary exposure--a time series study using whole body autoradiography

In the present study, the tissue distribution of [14C]-labelled 2,2',4,4'-tetrabrominated diphenyl ether (PBDE 47) and its possible metabolites was investigated after dietary exposure in pike (Esox lucius) using whole-body autoradiography. The study is a time series with pike examined 9, 18, 36 and 65 days after exposure. PBDE 47 was efficiently absorbed from the food (>90%) and radioactivity remained in the body in considerable amounts even after the longest period examined. The results indicate that PBDE 47 is not rapidly metabolised to hydrophilic, but possible to hydrophobic metabolites and that PBDE 47 and possible hydrophobic metabolites are accumulated in the lipid rich tissues of the pike. Melanin binding of PBDE 47 and possible metabolite(s) is suggested. The levels of PBDE 47 and/or metabolite(s) declines with time in most tissues except for the most lipid rich, where no decline in radioactivity is observed even after the longest period studied. Signs of irreversible incorporation of PBDE 47-derived radioactivity were detected but considered as too uncertain to conclude that covalent binding of PBDE 47-metabolites to macromolecules occurs.     

Effects of repeated fumonisin B1 exposure on markers of oxidative stress in liver,kidneys, and lungs of C57BL/6 mice

Abstract

Fu monisin B₁ (FB₁) is a mycotoxin commonly found in maize and maize-based products. Ingestion of FB₁-contaminated causes a myriad of dose- and species-dependent toxic effects to human and animal health. In the present study we evaluated the effects of FB₁ (8?mg/kg, i.p. for 4?days) on body weight and oxidative stress parameters in the liver, kidney and lung of C57BL/6 male mice. No changes in the organ-to-body weight ratio, organ-to-adrenal gland weight ratio or organ-to-brain weight ratio were found. On the other hand, FB₁ exposure increased NPSH levels in liver and lungs whereas decreased FRAP content in liver and kidneys. Levels of TBARS, ascorbic acid and NOx content were not altered by FB₁. In summary, four days of FB₁ exposure are sufficient to disrupt antioxidant defenses in liver, kidneys and lungs of C57BL/6 male mice without concomitant changes in organs weight.     

Effect of Tween 80 and beta-cyclodextrin on degradation of decabromodiphenyl ether (BDE-209) by White rot fungi

The environmental safety of decabromodiphenyl ether (BDE-209), a widely used flame retardant, has been the topic of controversial discussions during the past several years. Degradation of BDE-209 into lower brominated diphenyl ether congeners, exhibiting a higher bioaccumulation potential, has been a critical issue. White rot fungi are known to degrade a wide variety of recalcitrant pollutants. In this work, white rot fungi were used to degrade BDE-209 in liquid culture medium, and the effects of Tween 80 and beta-cyclodextrin on BDE-209 degradation by white rot fungi were evaluated. On the basis of these results, it appears that BDE-209 could be degraded by white rot fungi, and Tween 80 and beta-cyclodextrin can both increase the biodegradation. The best result in Tween 80 experiments was obtained at a Tween 80 concentration of 500mgl(-1) within 10d, which showed 96.5% (w/w) BDE-209 transformed. Tween 80 at a high concentration will restrain the fungal growth and the degradation of BDE-209. However, beta-cyclodextrin had positive effects both on the BDE-209 degradation and the fungal growth.     

Behavior of decabromodiphenyl ether (BDE-209) in soil: effects of rhizosphere and mycorrhizal colonization of ryegrass roots

A rhizobox experiment was conducted to investigate degradation of decabromodiphenyl ether (BDE-209) in the rhizosphere of ryegrass and the influence of root colonization with an arbuscular mycorrhizal (AM) fungus. BDE-209 dissipation in soil varied with its proximity to the roots and was enhanced by AM inoculation. A negative correlation (P < 0.001, R² = 0.66) was found between the residual BDE-209 concentration in soil and soil microbial biomass estimated as the total phospholipid fatty acids, suggesting a contribution of microbial degradation to BDE-209 dissipation. Twelve and twenty-four lower brominated PBDEs were detected in soil and plant samples, respectively, with a higher proportion of di- through hepta-BDE congeners in the plant tissues than in the soils, indicating the occurrence of BDE-209 debromination in the soil-plant system. AM inoculation increased the levels of lower brominated PBDEs in ryegrass. These results provide important information about the behavior of BDE-209 in the soil-plant system.     

Elimination of 10 polybrominated diphenyl ether (PBDE) congeners and selected polychlorinated biphenyls (PCBs) from the freshwater mussel, Elliptio complanata

Mussel biomonitors are widely used as screening tools for polybrominated diphenyl ethers (PBDEs) in marine and aquatic environments. This study determined elimination rate coefficients (k(tot)) for eight PBDE and five PCB congeners in the freshwater mussel, Elliptio complanata, over a 120d depuration period. Elimination of BDE 15, 28, 47, 75 and 100 was similar to PCBs of equivalent hydrophobicity and negatively related to chemical K(OW). Rapid elimination of BDE 190 and an inferred rapid elimination of BDE 183 indicate mussels are capable of biotransformation of certain highly brominated PBDEs. Time to 90% steady state ranged from 48 to 66d for di- and tribromoDE congeners and from 91 to >250d for tetra- to hexabromoDE congeners. Given the long time periods required for steady state, mussel accumulated PBDE residues should be interpreted in the context of calibrated bioaccumulation models.     

Evaluation of HODE-15, FDE-15, CDE-15, and BDE-15 toxicity on adult and embryonic zebrafish (Danio rerio)

Diphenyl ether and its derivatives are widely used in the industry of spices, dyes, agrochemicals, and pharmaceuticals. Following the previous study, we selected 4,4′-dihydroxydiphenyl ether, 4,4′-difluorodiphenyl ether, 4,4′-dichlorodiphenyl ether, and 4,4′-dibromodiphenyl ether as research objects. The LC₅₀ (96 h) values for these compounds in adult zebrafish were determined with the acute test. Also, developmental toxicities of the four substances to zebrafish embryos were observed at 24, 48, 72, and 96 hpf. All the LC₅₀ (96 h) values of these compounds were between 1 and 10 mg/L, suggesting that they all had moderate toxicity to adult zebrafish. The embryonic test demonstrated that with increasing doses, 4,4′-dihydroxydiphenyl ether decreased the hatching rate, while 4,4′-difluorodiphenyl ether, 4,4′-dichlorodiphenyl ether, and 4,4′-dibromodiphenyl ether delayed the hatching time but had little effect on final hatchability at 96 hpf. All of these compounds inhibited larval growth, especially 4,4′-dihydroxydiphenyl ether. Exposure to these chemicals induced embryo yolk sac and pericardial edema. Spine deformation was visible in hatched larvae after 96 hpf 4,4′-dihydroxydiphenyl ether exposure, while tail curvature was observed for the halogenated compounds. The overall results indicated that 4,4′-dihydroxydiphenyl ether, 4,4′-difluorodiphenyl ether, 4,4′-dichlorodiphenyl ether, and 4,4′-dibromodiphenyl ether all had significant toxicity on adult and embryonic zebrafish.     

Hepatic and immune biological effect assays in C57BL/6 mice to measure polycyclic aromatic hydrocarbon bioavailability under laboratory exposures with increasing environmental relevance

Background Monitoring biological responses that are mediated via the aryl-hydrocarbon receptor (AhR) in animals exposed to environmental contaminants can indicate both the presence to chemicals that act through this biochemical pathway and whether these chemicals are bioavailable. Objectives The use of an ex-situ method that incorporated biological responsiveness monitoring in mice for determining the presence of ‘biologically active’ hydrocarbons in contaminated soils was investigated. Methods The use of C57BL/6 as a test organism was validated by determining hepatic and immune responsiveness to two polyaromatic hydrocarbons (PAHs): 3,4 benz[a]pyrene (B[a]P) and 1,2 benz (a)anthracene (BA) administered via intraperitoneal (i.p.) injection. The responsiveness of mice exposed to soils spiked with hydrocarbons or ex situ exposures to soil removed from two contaminated sites was also investigated. Results and Discussion Mice that were exposed to B[a]P via i.p. injections showed a 14-fold increase in liver microsomal ethoxyresorufin O-deethylase (EROD) activity compared to the control group. In contrast EROD activity following BA exposure at the same level was not significantly enhanced. Mouse immune response was significantly inhibited in a dose-dependent manner by i.p. injections of B[a]P. No significant inhibition occurred with the same doses of BA. Following i.p. exposure, the retention of B[a]P in mouse carcasses was greater than BA. Mice exposed to clean soils spiked with environmentally relevant concentrations of B[a]P and BA failed to show any significantly different hepatic or immune responses. Carcass residue data indicated a limited uptake of PAH from the soil. In contrast, EROD activity in mice exposed (ex situ) to hydrocarbon-contaminated soils removed from a fuel-loading depot and decommissioned gas works was significantly enhanced (4- and 2-fold respectively). However, this increase in EROD activity did not appear to correlate with either soil or carcass PAH concentrations. Conclusions and Outlook These results support the assumption that B[a]P has a higher affinity for the aryl hydrocarbon receptor (AhR) compared to BA. Soil parameters such as organic carbon content, structure and particle size distribution can modulate the bioavailability of contaminants to biological receptors. These factors are implicated in the lack of responsiveness demonstrated in the spiked soil experiments. However the responsiveness of EROD activity in mice exposed (ex situ) to soil contaminated with complex mixtures of hydrocarbon compounds confirms the potential usefulness of this model to determine the presence of ‘biologically active’ compounds in aged soils removed from contaminated sites.     

A technical mixture of 2,2',4,4'-tetrabromo diphenyl ether (BDE47) and brominated furans triggers aryl hydrocarbon receptor (AhR) mediated gene expression and toxicity

Polybrominated diphenyl ethers (PBDE) are found as ubiquitous contaminants in the environment, e.g., in sediments and biota as well as in human blood samples and mother's milk. PBDEs are neuro- and developmental toxins, disturb the endocrine system and some are even carcinogenic. Structural similarities of PBDEs with dioxin-like compounds, e.g., 2,3,7,8-tetrachloro-dibenzodioxin (TCDD), have raised concern about a possible "dioxin-like" action of PBDEs. TCDD exerts its toxicity via binding to and activation of the aryl hydrocarbon receptor (AhR). AhR ligands are in contrast to PBDEs usually coplanar compounds. Thus, PBDEs are not likely to be strong AhR agonists. The aim of this study was to analyze the effects of the most abundant PBDE congener, 2,2',4,4'-tetrabromo diphenyl ether (BDE47), on AhR activity and signaling. Initially, we measured cytochrome P450 1A1 (Cyp1A1) induction as a readout for AhR activation by BDE47. Low grade purified BDE47 increased CYP1A1 levels in transformed and primary rat hepatocytes and human hepatoma cells. Chemical analysis of the BDE47 sample identified trace contaminations with brominated furans such as 2,3,7,8-tetrabromo dibenzodioxin (TBDF), which most likely were responsible for the observed activation of AhR. Subsequently, the BDE47 mixture was studied for its effect on AhR mediated toxicity and global gene expression. Indeed, in rat hepatoma cells and in zebrafish embryos the BDE47 mixture provoked changes in gene expression and toxicity similar to known AhR agonists. In addition to the dioxin-like actions, the BDE47 sample enhanced Cyp2B and Cyp3A expression suggesting that commercial PBDE mixtures, which also often contain brominated furans, may disturb cellular homeostasis at multiple levels.     

Bioaccumulation of halogenated aromatic hydrocarbons in C57B1/6 and DBA/2 mice following consumption of Great Lakes coho salmon (Oncorhynchus kisutch)

A gradation of polychlorinated biphenyl isomer and congener levels were found in coho salmon from Lakes Erie, Michigan and Ontario. A similar bioaccumulation pattern was observed in mouse livers following consumption of Great Lakes fish and, in general, the levels were higher in C57B1/6 than in DBA/2 mice.     

Occurrence of organochlorine insecticides, PCBs and PCB congeners in waters and sediments of the Ebro River (Spain)

Complex mixtures extracted from air filters exposed for 24 h in two sessions (27 July and 02 August 1991) and at two locations (Merced, downtown, and Pedregal de San Angel, south-west) in Mexico City were analysed. The organic extracts were from airborne particles equal or smaller than 10 microns (PM10), and from total suspended particles (TSP). These organic extracts were assayed in the somatic mutation and recombination test (SMART) in wings of Drosophila melanogaster using two different crosses as well as in the Salmonella/microsome assay using strain TA98 with and without S9 fraction. The presence of polycyclic aromatic hydrocarbons (PAH) in the extracts was determined by gas chromatography. The genotoxic activities observed in the two test systems were comparable with the indirect mutagens producing greater response than the direct mutagens. The quantities of particulate matter as well as the genotoxic activities were higher on 02 August than on 27 July 1991 for both locations. The amounts of airborne particles and the resulting genotoxic activities were higher at Merced than at Pedregal. In both biological systems, PM10 were more genotoxic than TSP. These results demonstrate the sensitivity of the Drosophila wing SMART-which is an in vivo eukaryotic genotoxicity assay-as a biological monitor of environmental pollution related to airborne particles.     

Analysis of difference in vivo effects of TCDD between c-src +/+ mice, c-src deficient, -/+ and -/- B6, 129-Src(tm 1 sor) mice and their wild-type littermates

Toxicities of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were tested on two strains of c-src deficient B6, 129-Src(tm 1 sor) mice, c-src -/+ and c-src -/- and their matched wild-type littermates c-src +/+ mice along with another c-src +/+ mice, from the same genetic lineage, B6, 129-Fos(tm 1 Pa) mice. The most conspicuous effect of c-src deficiency on the toxicity of TCDD appears to be the reduced hepatotoxicity. TCDD-treated c-src deficient mice show only modest degrees of hepatomegaly and triglycerides accumulation as compared to treated wild-type mice.     

Accumulation, tissue-specific distribution and debromination of decabromodiphenyl ether (BDE 209) in European starlings (Sturnus vulgaris)

In this study we investigated the accumulation, tissue-specific distribution and possible debromination of BDE 209 in a terrestrial songbird species, the European starling, using silastic implants as a method of exposure. BDE 209 accumulated in the blood of the exposed starlings to a mean peak concentration of 16+/-4.1 ng/ml on day 10. After this peak, there was a decline to 3.3+/-0.4 ng/ml blood at the end of the exposure period of 76 days, which suggests elimination of BDE 209. In the exposed group, the muscle concentrations (461 ng/g lipid weight [lw], 430 ng/g lw) were about twofold those in liver (269 ng/g lw, 237 ng/g lw). In addition to BDE 209, other PBDE congeners, particularly octa- and nonaBDEs, were also present in the muscle and liver, suggesting bioformation from BDE 209. To our knowledge, these results are the first indications for the debromination of BDE 209 in birds.     

Effects of perinatal exposure to bisphenol A and di(2-ethylhexyl)-phthalate on gonadal development of male mice

Purpose

In this study, we investigated the effects of maternal transfer of bisphenol A (BPA) and di(2-ethylhexyl) phthalate (DEHP) during gestational and weaning periods on gonadal development of male offspring.

Methods

Pregnant CD-1 mice were administered by gavages in corn oil with 0.1, 1, or 10 mg/kg/day of BPA and DEHP from gestational days (GD1?C21) to the weaning period (postnatal days (PND) 1?C21).

Results

Our data indicated that the exposure significantly reduced the male-to-female sex ratio and the sizes of the gonads of male pups as recorded at PND15. The testes of the perinatally exposed male pups were developed less and the expression levels of testicular anti-mullerian hormone, androgen receptor, cyclin A, and StAR were significantly lesser than the control male pups. The less developed testes were accompanied with significant reductions in the expression levels of Gnrh and Fsh at the hypothalamic?Cpituitary levels. The negative effects were found to be persistent in the sexually mature pups at PND42.

Conclusion

Our data reveal that the maternal transfer of BPA and DEHP may impose negative influence on the development and functions of the reproductive system of male pups.     

Bioaccumulation, depuration and biotransformation of 4,4'-dibromodiphenyl ether in crucian carp (Carassius auratus)

Polybrominated diphenyl ethers (PBDEs) are extensively used as a class of flame retardants and have become ubiquitous environmental pollutants. Significant biotransformation of some PBDEs via reductive debromination has been observed. However, little is known about the fate of lower brominated BDEs in fish. In this study, the tissue distribution, excretion, depuration and biotransformation of 4,4′-dibromodiphenyl ether (BDE 15) were investigated in crucian carp (Carassius auratus) which were exposed to spiked water solution at different concentrations for 50 d, followed by a 14-d depuration period. Bioaccumulation parameters were calculated and the results showed that BDE 15 was mainly concentrated in the gill and liver. In particular, five biotransformation products of BDE 15 in carp were identified using GC-MS/MS. Besides two debrominated metabolites, three of the metabolites were mono-OH-BDE 15, diOH-BDE 15 and bromophenol. Our results unequivocally suggested that BDE 15 oxidation did occur via the formation of hydroxylated (OH-) metabolites in crucian carp exposed in vivo. These findings will be useful for determination of the metabolic pathways of PBDEs in freshwater fish, especially about their oxidation metabolism.     

Sources, distribution and behaviour of methyl tert-butyl ether (MTBE) in the Tamar Estuary, UK

Negligible information is currently available concerning levels of the fuel additive methyl tert-butyl ether (MTBE) in European estuaries or coastal environments. MTBE was measured at selected potentially contaminated harbours and marinas, and throughout an axial transect of the Tamar Estuary, UK. Headspace solid-phase microextraction was used in combination with GC-MS for its determination. MTBE was detected in water samples from all stations at concentrations ranging from a few ng/l to a maximum of 194 ng/l (in a semi-enclosed harbour). Elevated levels were generally associated with motor vehicle and boating activities. The Tamar road and rail bridges provided a major input to the lower estuary, downstream of which conservative mixing appeared depressed, probably through volatilisation and possibly through salting-out. The selected analytical system (using a Carboxen/PDMS fiber) proved both rapid and highly sensitive (with a detection limit of 6 ng/l). During method development, salinity was shown to have a major influence in controlling the extraction efficiency and it was found necessary to adjust salinity in all samples (to 75% saturation) prior to extraction. From these tests, we (for the first time) estimated the Setschenow ("salting-out") constant of MTBE to be 0.11 l/mol.     

Predicting bioconcentration factors (BCFs) of polychlorinated bornane (Toxaphene) congeners in fish and comparison with bioaccumulation factors (BAFs) in biota from the aquatic environment.

Polychlorinated bornanes, the main components of Toxaphene, are bioconcentrated in aquatic organisms to a high extent. However, up to this time no bioconcentration tests with individual chlorinated bornanes in aquatic organisms have been performed. Therefore, the bioconcentration factors (BCFs) of seven selected persistent chlorinated bornane congeners which are regularly found in aquatic organisms, were predicted from their n-octanol/water partition coefficients (log Kow). Furthermore, these BCF values were compared with the measured bioaccumulation factors (BAFs) in zooplankton and different fish species from the aquatic environment.