Environmental occurrence, analysis, and toxicology of toxaphene compounds

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011

BACKGROUND

In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies.

METHODS

One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization.

RESULTS

The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai.

CONCLUSIONS

Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

Evidence for cometabolic transformation of weathered toxaphene under aerobic conditions using camphor as a co-substrate

AIMS

Toxaphene is a persistent organic pollutant, composed of approximately 1000 highly chlorinated bicyclic terpenes. The purpose of this study was to evaluate if camphor, a structural analogue of toxaphene, could stimulate aerobic biotransformation of weathered toxaphene.

METHODS AND RESULTS

Two enrichment cultures that degrade camphor as the sole carbon source were established from contaminated soil and biosolids. These cultures were used to evaluate aerobic transformation of weathered toxaphene. Only the biosolids culture could transform compounds of technical toxaphene (CTTs) in the presence of camphor, while no transformation was observed in the presence of glucose or with toxaphene as a sole carbon source. The transformed toxaphene had lower concentration of CTTs with longer retention times, and higher concentration of compounds with lower retention times. Gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) showed that aerobic biotransformation mainly occurred with Cl₈ - and Cl₉ -CTTs compounds. The patterns of Cl₆ - and Cl₇ -CTTs were also simplified albeit to a much lesser extent. Seven camphor-degrading bacteria were isolated from the enrichment culture but none of them could degrade toxaphene.

CONCLUSION

Camphor degrading culture can aerobically transform CCTs via reductive pathway probably by co-metabolism using camphor as a co-substrate.

SIGNIFICANCE AND IMPACT OF THE STUDY

Since camphor is naturally produced by different plants, this study suggests that stimulation of aerobic transformation of toxaphene may occur in nature. Moreover plants, which produce camphor or similar compounds, might be used in bioremediation of contaminated soils.

The organochlorine pesticide toxaphene reduces non-mitochondrial respiration and induces heat shock protein 70 expression in early-staged zebrafish (Danio rerio)

Toxaphene is a restricted-use pesticide produced by reacting chlorine gas with camphene. It was heavily used as a pesticide for agricultural purposes in the 1960-1970s, but despite being banned >30 years ago, it can remain elevated in the soil due to its resistance to metabolic degradation; this has led to longstanding concerns about elevated levels of toxaphene and other organochlorine pesticides (OCPs) in the environment. The objective of this study were to determine the effects of waterborne exposure to toxaphene on early life stages of zebrafish. Based on the LC₅₀, zebrafish embryos were exposed to control (embryo rearing media or DMSO) or to one dose of toxaphene ranging between 0.011 and 111.1 μg/mL from 6 h post fertilization (hpf) up to 120 hpf. Significant mortality and hatch time delays were observed in embryos exposed to toxaphene (at or above 0.11 and 1.11 μg/mL, depending on the assay). Higher prevalence of deformities was noted at higher doses (≥0.011 μg/mL), and these included pericardial edema and skeletal deformities. As energy production is important for normal development, mitochondrial bioenergetics were assessed in embryos following toxaphene exposure. Embryos exposed to 11.1 or 111 μg/mL toxaphene for 24 h showed lower non-mitochondrial respiration (~30%) compared to both solvent and no treatment controls. Expression of transcripts related to oxidative damage responses and apoptosis were measured and heat shock protein 70 was significantly increased with 111 μg/mL toxaphene (14.5 fold), while the expression levels of caspase 3, caspase 9, and superoxide dismutase 1 were not changed. These data demonstrate that developmental deformities induced by toxaphene include pericardial edema and skeletal deformity, and that toxaphene can affect oxidative phosphorylation in early staged zebrafish.

Analysis and Characterization of Polychlorinated Hydroxybornanes as Metabolites of Toxaphene Using a Polar Bear Model

Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) deactivated and (iii) activated silica gel. Hence, up to 320 and 4350 μg/kg lipid weight of octa- and nonachlorinated CTTs were detected in four liver samples and adipose tissue of polar bears, respectively. Furthermore, the presence of one hexachlorinated OH-CTT isomer could be verified in the samples, which was about 1% of the octachlorinated CTTs determined in the liver samples.

Effects of common-use pesticides on developmental and reproductive processes in Daphnia

Daphnia magna were evaluated for use as a screen for pesticides that have been demonstrated to have estrogenic (o?p?-DDT, di-n-butyl phthalate, toxaphene), anti-androgenic (p?p-DDE, linuron), thyroid (acetochlor, alachlor, metribuzin), insulin (amitraz) or lutenizing hormone (2,4-D) activity in vertebrates, and to establish daphnid sensitivity to these compounds. Pesticides with unknown effects on vertebrate endocrine systems (chlorosulfuran, cyanazine, diflubenzuron, metolachlor, and diquat) were also evaluated. Compounds were assayed for six days at environmentally relevant concentrations ranging from 0.001 to 100 mg/L, using female Daphnia and their offspring. Sublethal endpoints included offspring sex (sex determination), clutch size (fecundity), and adult size (growth rate). Toxaphene was the only compound that affected sexual differentiation, increasing male production. Daphnia fecundity declined with exposure to toxaphene, and daphnid growth rates were reduced by acetochlor exposure. Diflubenzuron, o?p?-DDT, and p?p-DDE significantly reduced Daphnia survival. No correlation existed between affected reproductive or developmental processes and specific endocrine systems or subsystems. Results from this study indicate that Daphnia make a good screen for assessing potential environmental impacts but are not a useful indicator of pesticide hormonal activity in vertebrates. This assay consistently detected sublethal but ecologically relevant effects of these pesticides on Daphnia at environmentally relevant concentrations typically below their listed EC50 value.

Chiral xenobiotics bioaccumulations and environmental health prospectives

The chiral xenobiotics are very dangerous for all of us due to the different enantioselective toxicities of the enantiomers. Besides, these have different enantioselective bioaccumulations and behaviors in our body and other organisms. It is of urgent need to understand the enantioselective bioaccumulations, toxicities, and the health hazards of the chiral xenobiotics. The present article describes the classification, sources of contamination, distribution, enantioselective bioaccumulation, and the toxicities of the chiral xenobiotics. Besides, the efforts are also made to discuss the prevention and remedial measures of the havoc of the chiral xenobiotics. The challenges of the chiral xenobiotics have also been highlighted. Finally, future prospectives are also discussed.

Sorption and competition of two persistent organic pesticides onto marine sediments: Relevance to their distribution in aquatic system

Sorption is a key process in the distribution of substances between environmental compartments in marine ecosystems. Two persistent organic pesticides, also known as toxaphene congeners, namely B8-1413 (P26) and B9-1679 (P50), are of special interest because they are not detected in sediments while relatively concentrated in marine mammals. Sorption-desorption, entrapment and competition behaviors of these pesticides onto marine sediments were studied to explain their environmental distribution. Data obtained under marine experimental conditions were fitted to sorption models to evaluate sorption coefficients and to assess the degree of B8-1413/B9-1679 entrapment of the two toxaphene congeners in sediments. Carbon normalized sorption coefficients (Koc) of both congeners were similar under in cold (2°C) marine (30 psu) conditions with high values ranging from 1.53×10(5) to 3.28×10(5) mL g(-1)indicative of a strong affinity to marine sediments However, the sorption-desorption investigations indicate that B8-1413/B9-1679 were on average 2.5 times less entrapped in sediments compared to B7-1450, a toxaphene congener known to accumulate predominantly in sediments. These results suggest that the low entrapment of B8-1413 and B9-1679 favor their availability and transfer to biological matrices.

Toxaphene in the aquatic environment of Greenland

The octa- and nonachlorinated bornanes (toxaphene) CHBs 26, 40, 41, 44, 50 and 62 were analysed in Arctic char (Salvelinus alpinus), shorthorn sculpin (Myoxocephalus scorpius), ringed seal (Pusa hispida) and black guillemot eggs (Cepphus grylle) from Greenland. Despite their high trophic level, ringed seals had the lowest concentrations of these species, with a Σ6Toxaphene median concentration of 13-20 ng/g lipid weight (lw), suggesting metabolisation. The congener composition also suggests transformation of nona- to octachlorinated congeners. Black guillemot eggs had the highest concentrations (Σ6Toxaphene median concentration of 971 ng/g lw). Although concentrations were higher in East than in West Greenland differences were smaller than for other persistent organic pollutants. In a circumpolar context, toxaphene had the highest concentrations in the Canadian Arctic. Time trend analyses showed significant decreases for black guillemot eggs and juvenile ringed seals, with annual rates of -5 to -7% for Σ6Toxaphene. The decreases were generally steepest for CHBs 40, 41 and 44.

Sorption behaviors of a persistent toxaphene congener on marine sediments under different physicochemical conditions

Sorptive processes are important parameters affecting the mobility, availability and fate of persistent organic pollutants (POPs), such as toxaphene, in aquatic systems. The sorption and desorption behaviors of the B7-1450, a stable toxaphene congener in environment, on marine sediment was studied under different temperature and salinity conditions to better understand the B-1450 distribution in estuarine systems. The data were fitted to different sorption models to characterize sorption behaviors by evaluating sorption coefficients and sequestrated fraction of B7-1450 on sediments. High carbon-normalized sorption coefficients (Koc) of the B7-1450 were observed with values ranging from 3.2×104 to 6.0×104 mL g(-1) under experimental conditions. The data showed an increase of B7-1450 sorption coefficients with the salinity and a decrease with temperature. These investigations indicate that B7-1450 is three times more sequestred on sediments in cold (2°C, 30 psu) than in warm marine conditions (20°C, 30 psu). These results suggest that the mobility and bioavailable of B7-1450 or other POPs from the sediments could be less important in cold marine comparatively in warm marine and warm freshwater media. As a result of climate changes, the warming of mid and high latitudes coastal waters could enhance the mobility of POPs.

A genome-wide screen identifies yeast genes required for tolerance to technical toxaphene, an organochlorinated pesticide mixture

Exposure to toxaphene, an environmentally persistent mixture of chlorinated terpenes previously utilized as an insecticide, has been associated with various cancers and diseases such as amyotrophic lateral sclerosis. Nevertheless, the cellular and molecular mechanisms responsible for these toxic effects have not been established. In this study, we used a functional approach in the model eukaryote Saccharomyces cerevisiae to demonstrate that toxaphene affects yeast mutants defective in (1) processes associated with transcription elongation and (2) nutrient utilization. Synergistic growth defects are observed upon exposure to both toxaphene and the known transcription elongation inhibitor mycophenolic acid (MPA). However, unlike MPA, toxaphene does not deplete nucleotides and additionally has no detectable effect on transcription elongation. Many of the yeast genes identified in this study have human homologs, warranting further investigations into the potentially conserved mechanisms of toxaphene toxicity.

Using quantitative structural property relationships, chemical fate models, and the chemical partitioning space to investigate the potential for long range transport and bioaccumulation of complex halogenated chemical mixtures

Some substances are mixtures of very large number of constituents which vary widely in their properties, and thus also in terms of their environmental fate and the hazard that they may pose to humans and the environment. Examples of such substances include industrial chemicals such as the chlorinated paraffins, technical pesticides such as toxaphene, and unintended combustion side products, such as mixed halogenated dibenzo-p-dioxins and dibenzofurans. Here we describe a simple graphical superposition method that could precede a more detailed hazard assessment for such substances. First, partitioning and degradation properties for each individual constituent of a mixture are estimated with high-throughput quantitative structure-property relationships. Placed in a chemical partitioning space, i.e. a coordinate system defined by two partitioning coefficients, the mixtures appear as 'clouds'. When model-derived hazard assessment metrics, such as the potential for bioaccumulation and long range transport, are superimposed on these clouds, the resulting maps identify the constituents with the highest value for a particular parameter and thus potentially the greatest hazard. The maps also indicate transparently how the potential for long range transport and bioaccumulation is dependent on structural attributes, such as chain length, and the degree and type of halogenation. In contrast to previous approaches, in which the mixture is represented by a single set of properties or those of a few selected constituents, the whole range of environmental fate behaviors displayed by the constituents of a mixture are being considered. The approach is illustrated with three sets of chemical substances.

Comparative survey of levels of chlorinated cyclodiene pesticides in breast milk from some cities of China, Korea and Japan

Exposure of mothers to organochlorine pesticides (OCPs) was assessed by measuring the levels of 20 OCPs in 70 human breast milk samples pooled from 210 individuals from China, Korea and Japan. The OCPs were analyzed using gas chromatography/mass spectrometry (GC/MS) in electron capture negative ionization (ECNI) monitoring. The results showed that β-hexachlorocyclohexane and hexachlorobenzene were one order of magnitude higher in China than in the other nations, whereas chlordanes and polychlorinated biphenyl levels were highest in Japan. Heptachlor epoxide, dieldrin, endrin, toxaphenes and mirex were detected in most samples, and levels of these chemicals were significantly higher in Japan (0.8-4.5 ng g(-1) lipid), followed by Korea (0.2-4.7 ng g(-1) lipid), and lowest in China (less than 1.0 ng g(-1) lipid). α- and β-endosulfans were detected at a range of 0.9-1.5 ng g(-1) lipid levels in all samples analyzed, and their levels were higher in Korean than in Chinese samples.

Toxicological risks to humans of toxaphene residues in fish

A revised risk assessment for toxaphene was developed, based on the assumption that fish consumers are only exposed to toxaphene residues that differ substantially from technical toxaphene due to environmental degradation and metabolism. In vitro studies confirmed that both technical toxaphene and degraded toxaphene inhibit gap junctional intercellular communication that correlates with the mechanistic potential to cause tumor promotion. In vivo rat studies established the NOAEL for degraded and technical toxaphene at the highest dose tested in the bioassay. Toxaphene residue intakes from European fishery products were estimated and compared to the provisional tolerable daily intakes (TDIs) from various regulatory agencies including Canada, the United States, and Germany. The estimated intake was also compared to a new calculated provisional MATT pTDI. The MATT pTDI is based on new toxicological information (in vivo rat studies) developed on a model for environmental toxaphene residues rather than technical toxaphene. A MATT pTDI (1.08 mg total toxaphene for a person of 60 kg) for tumor promotion potency was adopted for use in Europe and is referred to here as the MATT pTDI. These new data result in a better estimate of safety and a higher TDI than previously used. Based on realistic fish consumption data and recent baseline concentration data of toxaphene in European fishery products, the toxaphene intake for the consumers of Germany, Ireland, Norway, and the Netherlands was estimated. For an average adult fish consumer, the average daily intake of toxaphene was estimated to be 1.2, 0.4, 0.5, and 0.2 µg for the consumers of Norway, Germany, Ireland, and the Netherlands, respectively. The toxaphene intake of these average fish consumers was far below the MATT pTDI of 1.08 mg/60 kg bw. In conclusion, based on the most relevant toxicological studies and the most realistic estimates of fish consumption and recent concentrations of toxaphene in European fishery products, adverse health effects are unlikely for the average European consumer of fishery products. In no case is the MATT pTDI exceeded.

Toxaphene affects the levels of mRNA transcripts that encode antioxidant enzymes in Hydra

We evaluated toxaphene-induced acute toxicity in Hydra magnipapillata. The median lethal concentrations of the animals (LC(50)) were determined to be 34.5 mg/L, 25.0 mg/L and 12.0 mg/L after exposure to toxaphene for 24 h, 48 h and 72 h, respectively. Morphological responses of hydra polyps to a range of toxaphene concentrations suggested that toxaphene negatively affects the nervous system of H. magnipapillata. We used real-time quantitative PCR of RNA extracted from polyps exposed to two concentrations of toxaphene (0.3 mg/L and 3 mg/L) for 24 h to evaluate the differential regulation of levels of transcripts that encode six antioxidant enzymes (CAT, G6PD, GPx, GR, GST and SOD), two proteins involved in detoxification and molecular stress responses (CYP1A and UB), and two proteins involved in neurotransmission and nerve cell differentiation (AChE and Hym-355). Of the genes involved in antioxidant responses, the most striking changes were observed for transcripts that encode GPx, G6PD, SOD, CAT and GST, with no evident change in levels of transcripts encoding GR. Levels of UB and CYP1A transcripts increased in a dose-dependent manner following exposure to toxaphene. Given that toxaphene-induced neurotoxicity was not reflected in the level of AChE transcripts and only slight accumulation of Hym-355 transcript was observed only at the higher of the two doses of toxaphene tested, there remains a need to identify transcriptional biomarkers for toxaphene-mediated neurotoxicity in H. magnipapillata. Transcripts that respond to toxaphene exposure could be valuable biomarkers for stress levels in H. magnipapillata and may be useful for monitoring the pollution of aquatic environments.

Historical trends in human dietary intakes of endosulfan and toxaphene in China, Korea and Japan

Recently, the Stockholm Convention prohibited the use of toxaphene and has been reviewing endosulfan. The historical use of these pesticides may contaminate food and tend to accumulate in the food chain. In this study, to evaluate the spatial and temporal trends of food contamination, the endosulfan and toxaphene levels were measured in pooled 24-h food composite samples from Chinese (n=10), Korean (n=10) and Japanese (n=40) adults in the 1990s and 2007-2009. Endosulfan was detected in 32 of 40 samples from Japan, but its levels (sum of α- and β-isomers) were low in both the 1990s and 2009 (range as geometric mean (geometric standard deviation) [GM (GSD)]: 0.96 (1.6)-1.42 (1.4) ng kg(-1)d(-1)). The dietary intakes of endosulfan in Seoul as GM (GSD) were 38.68 (1.3) ng kg bw(-1)d(-1) in 1994 and 92.17 (4.4) ng kg bw(-1)d(-1) in 2007, and significantly higher than those in Japan (p<0.05). The samples from Beijing showed a 50-fold increase in the endosulfan levels from 1993 (GM: 0.58 ng kg(-1)d(-1)) to 2009 (GM: 24.91 ng kg bw(-1)d(-1)) (p<0.05). Toxaphene was detected in 33 of 40 samples from Japan. The dietary intake of toxaphene in Japan (sum of Parlars #26, #50 and #62) was 0.32-1.21 ng kg bw(-1)d(-1) (range as geometric mean) and no temporal trend was observed. The dietary intake of toxaphene in Seoul increased significantly from 0.2 ng kg bw(-1)d(-1) (GM) in 1994 to 3.6 ng kg bw(-1)d(-1) (GM) in 2007 (p<0.05). Only one of 10 pooled samples from Beijing contained a detectable level of toxaphene (0.3 ng kg bw(-1)d(-1)). For the entire population, the risk of adverse health effects from dietary intakes of endosulfan and toxaphene is unlikely. However, the concentrations of endosulfan in several samples exceeded 10% of the acceptable daily intake limit value of 6 μg kg bw(-1)d(-1) set by the World Health Organization (WHO). It appears important to refine dietary intake estimates targeting food types and source identification to ensure safe food for consumers.

Transcriptional response of marine medaka (Oryzias javanicus) on exposure to toxaphene

Differential gene expression profiles were established from the head and liver tissues of the marine medaka fish (Oryzias javanicus) after its exposure to toxaphene, a persistent organic pollutant and insecticide, using differential display polymerase chain reaction. Twenty-seven differentially expressed genes were identified, which were associated with the cytoskeleton, development, metabolism, nucleic acid/protein binding, and signal transduction. Among these genes, those encoding molecular biomarkers known to be involved in metabolism, ATP hydrolysis, and protein regulation were strongly induced at the transcription level, and genes encoding one structural protein subunit or involved in lipid metabolism were strongly downregulated. The same trends in gene expression changes were observed with real-time PCR analysis of 12 selected clones. The genes identified could be used as molecular biomarkers of biological responses to polychlorinated camphene contamination in aquatic environments.

Modeling toxaphene behavior in the Great Lakes

Chlorinated camphenes, toxaphene, are persistent organic pollutants of concern in the Great Lakes since elevated concentrations are found in various media throughout the system. While concentrations have decreased since their peak values in the 1970s and 80s, recent measurements have shown that the rate of this decline in Lake Superior has decreased significantly. This modeling study focused on toxaphene cycling in the Great Lakes and was performed primarily to determine if elevated water and fish concentrations in Lake Superior can be explained by physical differences among the lakes. Specifically, the coastal zone model for persistent organic pollutants (CoZMo-POP), a fugacity-based multimedia fate model, was used to calculate toxaphene concentrations in the atmosphere, water, soil, sediment, and biota. The performance of the model was evaluated by comparing calculated and reported concentrations in these compartments. In general, simulated and observed concentrations agree within one order of magnitude. Both model results and observed values indicate that toxaphene concentrations have declined in water and biota since the 1980s primarily as the result of decreased atmospheric deposition rates. Overall the model results suggest that the CoZMo-POP2 model does a reasonable job in simulating toxaphene variations in the Great Lakes basin. The results suggest that the recent findings of higher toxaphene concentrations in Lake Superior can be explained by differences in the physical properties of the lake (primarily large volume, large residence time and cold temperatures) compared to the lower lakes and increased recent inputs are not needed to explain the measured values.

Organohalogen pollutants in herring from the northern Baltic Sea: concentrations, congener profiles and explanatory factors

Organohalogen contaminants were investigated in Baltic herring caught from three catchment areas in the Baltic Sea, off the coasts of Finland. Pools of both small and large herring were analysed for polychlorinated biphenyls (PCB), dibenzo-p-dioxins, dibenzofurans, naphthalenes, camphenes (toxaphene), polybrominated diphenyl ethers and the pesticide DDT and its metabolites. PCB concentrations per fresh weight in small herring were at the same level in all catchment areas, i.e. the Bothnian Bay, the Bothnian Sea and the Gulf of Finland, revealing no hot spots and reflecting most likely long term emissions and atmospheric deposition. Differences in the levels and/or congener profiles of other contaminants between catchment areas may be explained by point sources. Similar concentrations in small and large herring in the Gulf of Finland were possibly due to their common nutrition. In the other areas, differences between small and large herring most likely reflected their different food sources.

Evaluation of tumour promoting potency of fish borne toxaphene residues, as compared to technical toxaphene and UV-irradiated toxaphene

In this study the potential impact of food chain-based biotransformation and physico-chemical weathering of toxaphene on its tumour promoting potential was investigated in vitro and in vivo. Human exposure to toxaphene is mainly through consumption of contaminated fish, therefore fish-borne residues of toxaphene (cod liver extract, CLE) were prepared by exposing cod to technical toxaphene (TT) for 63 days. UV-irradiated toxaphene (uvT) was included to represent a physico-chemical weathered toxaphene mixture. In vitro, TT, uvT and CLE all showed a dose- and time-dependent inhibition of gap junctional intercellular communication (GJIC) with a relative potency of CLE>TT=uvT. Tumour promoting potency was further studied in vivo in a medium term two-stage initiation/promotion bioassay in female Sprague-Dawley rats, using an increase in altered hepatic foci positive for glutathione-S-transferase-P (AHF-GST-P) as read out. No increase in AHF-GST-P occurred following exposure to either TT, uvT, or CLE, except for the positive control group (2,3,7,8-TCDD). Based on this study the no observed adverse effect level (NOAEL) for tumour promoting potency is at least 12.5mg/kg/week, or higher for CLE. Considering current human exposure levels in Europe it is doubtful that consumption of fish at current levels of toxaphene contamination give rise to human health risk.

Toxaphene in minke whales (Balaenoptera acutorostrata) from the North Atlantic

Toxaphene contamination of minke whales (Balaenoptera acutorostrata) from North Atlantic waters was examined for the first time. Total toxaphene and SigmaCHB (sum of 11 chlorobornanes) concentrations in blubber samples ranged from 170+/-110 and 41+/-39 ng/g lipid weight (l.w.) for female minke whales from southeastern Greenland to 5800+/-4100 and 1100+/-780 ng/g l.w. for males from the North Sea, respectively. Very large variations in toxaphene concentrations among sampling areas were observed suggesting a spatial segregation of minke whales. However, much of the apparent geographical discrimination was explained by the seasonal fluctuation of animal fat mass. Patterns of CHBs in males revealed that recalcitrant CHBs were in higher proportions in animals from the more easterly areas than in animals from the more westerly areas. This trend may be influenced by the predominance of the US, over the European, input of toxaphene to North Atlantic waters.

Investigations on the sorption of a toxaphene model congener, the B7-1450, on marine sediments

Sorption is a natural process that takes place in sediments or soils and changes the mobility and availability of hydrophobic organic compounds, such as toxaphene pesticide in the environment. The sorption of the 2-exo,3-endo,5-exo,8,9,10,10-heptachlorobornane (B7-1450), used as a model compound of the toxaphene heptachlorobornane congeners found in sediments, was investigated for the first time through a series of batch sorption experiments. The losses of B7-1450 due to adsorption onto glass walls and to evaporation occurring during analytical treatment steps were corrected. The study showed that these specific losses ranged from 2% to 3.5% for the glass walls adsorption and can be as high as 15% for the evaporation treatment. The sorption coefficients, K(d) and K(oc), of B7-1450 could be overestimated by >30%, particularly for low-concentration samples, if the losses were not corrected. Loss correction equations were established, validated and applied to determine sorption coefficients for the B7-1450 congener. The K(oc) values for B7-1450 determined over a gradient of concentrations ranged from 3.5x10(4) to 6.5x10(4)mlg(-1), revealing a strong affinity of B7-1450 for marine sediments.

Neurochemical targets and behavioral effects of organohalogen compounds: an update

Organohalogen compounds (OHCs) have been used and still are used extensively as pesticides, flame retardants, hydraulic fluids, and in other industrial applications. These compounds are stable, most often lipophilic, and may therefore easily biomagnify. Today these compounds are found distributed both in human tissue, including breast milk, and in wildlife animals. In the late 1960s and early 1970s, high levels of the polychlorinated biphenyls (PCBs) and the pesticide dichlorodiphenyl trichloroethane (DDT) were detected in the environment. In the 1970s it was discovered that PCBs and some chlorinated pesticides, such as lindane, have neurotoxic potentials after both acute and chronic exposure. Although the use of PCBs, DDT, and other halogenated pesticides has been reduced, and environmental levels of these compounds are slowly diminishing, other halogenated compounds with potential of toxic effects are being found in the environment. These include the brominated flame retardants, chlorinated paraffins (PCAs), and perfluorinated compounds, whose levels are increasing. It is now established that several OHCs have neurobehavioral effects, indicating adverse effects on the central nervous system (CNS). For instance, several reports have shown that OHCs alter neurotransmitter functions in CNS and Ca2+ homeostatic processes, induce protein kinase C (PKC) and phospholipase A2 (PLA2) mobilization, and induce oxidative stress. In this review we summarize the findings of the neurobehavioral and neurochemical effects of some of the major OHCs with our main focus on the PCBs. Further, we try to elucidate, on the basis of available literature, the possible implications of these findings on human health.

Advances in the environmental analysis of polychlorinated naphthalenes and toxaphene

Recent advances in the analysis of the chlorinated environmental pollutants polychlorinated naphthalenes (PCNs) and toxaphene are highlighted in this review. Method improvements have been realized for PCNs over the past decade in isomer-specific quantification, peak resolution, and the availability of mass-labeled standards. Toxaphene method advancements include the application of new capillary gas chromatographic (GC) stationary phases, mass spectrometry (MS), especially ion trap MS, and the availability of Standard Reference Materials that are value-assigned for total toxaphene and selected congener concentrations. An area of promise for the separation of complex mixtures such as PCNs and toxaphene is the development of multidimensional GC techniques. The need for continued advancements and efficiencies in the analysis of contaminants such as PCNs and toxaphene remains as monitoring requirements for these compound classes are established under international agreements.

Determination of toxaphene enantiomers by comprehensive two-dimensional gas chromatography with electron-capture detection

Comprehensive two-dimensional gas chromatography with micro electron-capture detection (GC x GC-microECD) has been evaluated for the enantioseparation of five chiral toxaphenes typically found in real-life samples (Parlar 26, 32, 40, 44 and 50). From the two enantioselective beta-cyclodextrin-based columns evaluated as first dimension column, BGB-176SE and BGB-172, the latter provided the best results and was further combined with three non-enantioselective columns in the second dimension: HT-8, BPX-50 and Supelcowax-10. The combination BGB-172 x BPX-50 was finally selected because it provided a complete separation among all enantiomers. A satisfactory repeatability and reproducibility of the retention times in both the first and the second dimension were observed for all target compounds (RSDs below 0.8%, n = 4). Linear responses in the tested range of 10-200 pg/microl and limits of detection in the range of 2-6 pg/microl were obtained. The repeatability and reproducibility at a concentration of 100 pg/microl, evaluated as the RSDs calculated for the enantiomeric fraction (EF), was better than 11% (n = 4) in all instances. The feasibility of the method developed for real-life analyses was illustrated by the determination of the enantiomeric ratios and concentration levels of the test compounds in four commercial fish oil samples. These results were compared to those obtained by heart-cut multidimensional gas chromatography using the same enantioselective column.

Organochlorine levels in edible fish from the Marmara Sea, Turkey

Samples of 12 edible fish species from the Marmara Sea were analyzed for organochlorines (PCBs, DDTs, HCB, HCHs, toxaphene, etc.). The results showed that the total concentrations ranged from 329.41 ng/g fat to 1453.87 ng/g fat. DDT group components made up almost half or more of organochlorine contamination. Levels in red mullet were compared with those from neighbor seas. The sum of DDTs as well as HCHs concentrations were markedly lower than in the Black Sea but higher in the Aegean Sea and Mediterranean. Thus, inflow from the Black Sea might be considered as a contamination source for DDT and HCH contamination. On the other hand, total PCB concentration (sum of congeners 28, 52, 101, 118, 138, 153 and 180) detected in this study was comparable or lower than those from the Aegean Sea and Mediterranean. Toxaphene was a minor contaminant. Measured values were below maximum residue levels for human consumption.

Development of a reference dose for the persistent congeners of weathered toxaphene based on in vivo and in vitro effects related to tumor promotion

Toxaphene is a mixture of chlorinated camphenes and bornanes that was produced and used in the United States until 1982. 1.3 million tons of toxaphene have been released worldwide. "Technical" toxaphene (TT) consists of a mixture of up to 800 different chemicals, known as congeners. TT weathers in the environment by both biotic and abiotic processes. The human body burden of toxaphene consists of only five persistent congeners that are not metabolized; three of these occur in considerably greater amounts than the other two. Because of the rapid metabolism and excretion of the non-persistent congeners, the persistent congeners that make up the human body burden most likely play a role in eliciting any potential adverse effects. EPA's toxicity assessment for TT is based on the occurrence of liver cancer in rodents, and considerable doubt exists whether this assessment is applicable to weathered toxaphene (WT). Using experimental results from European Union scientists, a reference dose (RfD) was developed for WT based on the three most persistent congeners that comprise the human body burden. The critical effect chosen was tumor promotion and this endpoint is considered protective for other endpoints as well. Although RfDs are typically derived for non-carcinogenic effects, the endpoint of tumor promotion is appropriate for RfD development because the experimental data suggest a dose threshold. The RfD for weathered toxaphene represented by the sum of the three major persistent congeners ( summation 3PC) is 2E-05 mg/kg-day. To apply this reference dose to a particular WT mixture, information is needed regarding the percentage of summation 3PC in the mixture.

Levels of toxaphene congeners in white whales (Delphinapterus leucas) from Svalbard, Norway

This study reports concentrations of three pesticide toxaphene congeners (CHBs; CHB-26, -50 and -62) from the blubber of ten adult, male white whales (Delphinapterus leucas) from Svalbard, Norway. The CHB congeners that occurred at the highest levels in the blubber of the white whales were, as expected, CHB-26 (4636+/-1992 (SD) ng/g l.w.) and CHB-50 (6579+/-2214 ng/g l.w.); CHB-62 (232+/-231 ng/g l.w.) was also present, but at much lower concentrations. The mean level of the sum of the three CHBs (SigmaCHBs = 11,447+/-4208 ng/g l.w.) in this study is more than twice the mean concentrations of the well-known organochlorine (OC) pollutants SigmaDDTs (sum of pp'-DDT, pp'-DDE, pp'-DDD) and SigmaPCBs (sum of 27 PCB congeners) previously reported from the same individual white whales. The concentrations of CHBs in white whales from Svalbard are at the high end of the range for concentrations of these compounds compared to other Arctic white whale populations. Additionally, the contribution of CHBs to the overall OC burden is larger in white whales from Svalbard compared with their counterparts from other areas in the Arctic. Male white whales from Svalbard have several orders of magnitude higher concentrations of SigmaCHBs compared to seals and polar bears (Ursus maritimus) from the same area. The high levels of CHBs in these whales, and their dominance in the OC pattern, suggests that white whales in Svalbard are exposed to high levels of this group of contaminants. Further studies are needed to investigate possible effects of CHBs and other OC contaminants on the white whale population in Svalbard.

Very high concentrations of DDE and toxaphene residues in crocodiles from the Ord River, Western Australia: an investigation into possible endocrine disruption

Organochlorine pesticide concentrations, particularly those of the DDT family and of toxaphene, were measured by gas chromatography in samples of liver and body fat taken from Australian freshwater crocodiles Crocodylus johnstoni at three locations along the Ord River in Western Australia. The three sampling sites were the irrigation area, downstream of the irrigation area, and well upstream of the irrigation area; the last site serving as the control. DDT and toxaphene were applied in large and known quantities to cotton grown in the Ord Irrigation Area from 1964 to 1974. Thus the residues in the crocodile tissues are representative of the situation almost thirty years after the use of DDT and toxaphene ceased in the area. Very high concentrations of p,p'-DDE and toxaphene were found in the lipid-rich tissues that were examined. Livers and body fat from estuarine crocodiles Crocodylus porosus from the downstream site were also analysed. As p,p'-DDE and toxaphene are both known to be disruptive of endocrine systems, a range of blood parameters, including estradiol and testesterone concentrations, were also measured for all the animals studied. The ovaries and testes of the freshwater crocodiles were also examined histologically. There were no obvious effects on blood chemistry or gonad histology of the large burden of pesticides and their metabolites carried by exposed animals, although the limited number of samples and the variability of the breeding state of the animals examined may have masked possible effects. The isolation of the area, the accurately known applications of DDT and toxaphene, and the simplicity of the drainage system make the lower Ord River a unique natural laboratory for studying the long term breakdown and effects of pesticides applied in a tropical environment.

Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjørnøya (Bear Island) freshwater biota

Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjørnøya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjøen. In Lake Øyangen, located only 5 km north of Ellasjøen, levels of these contaminants were significantly lower. delta(15)N-values were 7-10 per thousand higher in organisms from Ellasjøen as compared to Øyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjøen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study.

Genotoxic activity of a technical toxaphene mixture and its photodegradation products in SOS genotoxicity tests

Toxaphene (CAS No. 800-35-2) is a complex mixture of several hundred components that was used worldwide primarily as an agricultural pesticide with insecticide effects in the second half of the 20th century. In vitro investigations of the genotoxicity and mutagenicity of toxaphene were generally described in the literature, but they provided somewhat equivocal results. We re-evaluated the genotoxicity of technical toxaphene in two prokaryotic systems. The SOS Chromotest showed high sensitivity to toxaphene: three concentrations (40, 20 and 10 mg/l) were clearly positive and the dose-response effect was evident. In the umuC assay, a dose-dependent increase in genotoxic activity was observed at toxaphene concentrations from 2.5 to 40.0 mg/l, but these results were found to be not significant. The genotoxicity of toxaphene and its photodegradation products after UV-irradiation (3-6-9 h) at concentrations ranging from 7.5 to 60.0 mg/l was also examined in this study. An irradiated solution of technical toxaphene after 3 h showed no significant evidence of bacterial growth inhibition. However, exposure of Salmonella to 6 h UV-irradiated toxaphene showed a toxic effect compared with the negative control. After 9 h irradiation, a decrease of bacterial growth was observed. Activity of beta-galactosidase in the presence of a toxaphene solution was significantly increased after 6 and 9 h irradiation, reaching values that were 2.4- and 3.1-fold higher, respectively, than the control, which exceeded the criteria of significant genotoxicity. These results show that while technical toxaphene is a weak, direct-acting mutagen in some bacterial tests, a dose-dependent toxicity and genotoxicity of its photoproducts could be conclusively demonstrated by the umuC test.

Comparative effects of technical toxaphene, 2,5-dichloro-3-biphenylol and octabromodiphenylether on cell viability, [Ca2+]i levels and membrane fluidity in mouse thymocytes

Flow cytometric studies of mouse thymocytes show that technical toxaphene (10-20 ppm) and 2,5-dichloro-3-biphenylol (PCB 9-OH) (5-10 ppm) kill cells and cause an increase in intracellular calcium concentration, [Ca2+]i, whereas commercial octabromodiphenylether (OBDE) has no effect. The cell death is not a result of the rise of [Ca2+]i, since the divalent cation ionophore, ionomycin, causes a large elevation in [Ca2+]i without cell death. We have studied effects of these compounds on membrane fluorescence polarization, a measure of membrane fluidity, using 1,6-diphenyl-1,3,5-hexatriene (DPH). We find that toxaphene causes a decrease in membrane fluidity in the concentration range associated with cell death, whereas PCB 9-OH causes an increase in fluidity and OBDE has no effect. These observations suggest that alterations of membrane fluidity of thymocytes, whether it be an increase or decrease, can cause cytotoxicity.

Toxaphene detoxification and acclimation in Daphnia magna: do cytochrome P-450 enzymes play a role?

Toxaphene is a persistent environmental contaminant that has been shown to alter male production in Daphnia magna and to induce P-450 activity in mammals. Cytochrome P-450-mediated metabolism may lead to xenobiotic detoxification resulting in acclimation. To determine if D. magna acclimate to toxaphene via P-450 pathways, chronic and acute toxicity tests were conducted with D. magna exposed to toxaphene in the presence and absence of piperonyl butoxide (PBO), an inhibitor of cytochrome P-450 enzymes. Toxaphene exposure increased male production in acute but not chronic assays, indicating that D. magna may acclimate to chronic toxaphene exposure. Upon co-administration of toxaphene and PBO in chronic tests, D. magna exhibited a decline in growth rate, fecundity and survival. The observed toxaphene acclimation in chronic tests, along with its increased toxicity in the presence of a P-450 suppressor, suggests that P-450 enzymes may contribute to detoxification and subsequent acclimation of D. magna to chronic toxaphene exposure. Additional chronic toxicity tests indicated that toxaphene acclimation occurs between 7 and 12 days following initial exposure, at which time sex determination is no longer affected. Thus, sublethal toxaphene toxicity effects such as reproductive impairments may be detectable with acute but not chronic tests, potentially due to the upregulation of P-450 isozymes.

Developments in the use of chromatographic techniques in marine laboratories for the determination of halogenated contaminants and polycyclic aromatic hydrocarbons

Chromatography has been an important tool in marine laboratories. Since the 1960s, marine laboratories have been involved in the analysis of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and brominated flame retardants (BFRs). Column chromatography and liquid chromatography (LC) techniques have been used, mainly in the clean-up phase, while gas chromatography (GC) has been used extensively in the final determination of these contaminants. Developments have been observed from the use of packed GC columns, via capillary columns to the use of heart-cut multi-dimensional GC and comprehensive multi-dimensional GC. The progress made in interlaboratory studies and the availability of certified reference materials are discussed.

A review of environmental toxicant analysis by using multidimensional gas chromatography and comprehensive GC

The purpose of this review is to highlight the developments in coupled-column gas chromatography methods for qualitative analysis of selected environmental toxicants such as dioxin, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), etc. In particular, the new technique of GC x GC will be introduced, and its role, and the promise it offers to this field is discussed. The benefits of enhanced separation to quantitative analysis will be considered. In order to perform an accurate risk assessment, both the dose and biological effects of environmental toxicants have to be determined with a high degree of certainty. This is most often achieved by using chromatographic methods. Given the complexity of most environmental sample extracts, single-column gas chromatography is unable to fully resolve all the components of interest frequently leading to a positive bias in the reported concentrations. Advanced separation tools, such as multidimensional gas chromatography (MDGC), were investigated quite early and demonstrated improvements in separation. However, limitations in the number of target analytes that could be analyzed in a single run as well as insufficient robustness lead to a continued interest in alternative solutions. The parallel development of mass spectrometric identification and quantification strategies proved useful in many cases, although it frequently failed to provide positive identification of chromatographically unresolved isomeric compounds. More recently, comprehensive two-dimensional gas chromatography (GC x GC) may offer a solution to that problem, especially because it offers enhanced resolution for complex mixtures containing trace level environmental toxicants.

Polychlorinated camphenes (toxaphenes), polybrominated diphenylethers and other halogenated organic pollutants in glaucous gull (Larus hyperboreus) from Svalbard and Bjørnøya (Bear Island)

The levels of polychlorinated camphenes (toxaphenes) were investigated in liver samples from 18 glaucous gulls (Larus hyperboreus) from Bjørnøya (74 degrees N, 19 degrees E) and four individuals from Longyearbyen (78 degrees N, 15 degrees E). Additionally brominated flame retardants (BFRs), PCBs and chlorinated pesticides were investigated in liver and intestinal contents of 15 of the glaucous gulls from Bjørnøya. Of the analysed BFRs only 2,2',4,4'-tetra- and 2,2',4,4',5-pentabrominated diphenylethers (PBDE 47 and 99) could be detected. The concentrations ranged between 2 and 25 ng/g ww. In addition, high resolution measurements with GC/HRMS revealed the existence of several, not quantified, PBDEs and polybrominated biphenyls (PBBs) congeners in the samples. B9-1679 and B8-1413 were the dominating toxaphenes with median concentrations of 8 and 15 ng/g ww. Concentrations of toxaphenes and PBDEs were up to 100-times lower than the concentrations of PCB and some of the pesticides. PCB and p,p/-DDE constituted 90% of the contaminants found.

Toxaphene, but not beryllium, induces human neutrophil chemotaxis and apoptosis via reactive oxygen species (ROS): involvement of caspases and ROS in the degradation of cytoskeletal proteins

Chemicals of environmental concern are known to alter the immune system. Recent data indicate that some contaminants possess proinflammatory properties by activating neutrophils, an area of research that is still poorly investigated. We have previously documented that toxaphene activates human neutrophils to produce reactive oxygen species (ROS) and accelerates apoptosis by a yet unknown mechanism. In this study, we found that toxaphene induces another neutrophil function, chemotaxis. Furthermore, we found that toxaphene induces both chemotaxis and apoptosis via a ROS-dependent mechanism, since these responses were blocked by the addition of catalase to the culture. In addition, toxaphene was found to induce the degradation of the cytoskeletal proteins gelsolin, paxillin, and vimentin during apoptosis, and this was reversed by the addition of z-VAD-FMK (caspase inhibitor) or catalase, demonstrating the importance of caspases and ROS in this process. In contrast to toxaphene, we found that beryllium does not induce superoxide production, and, this correlates with its inability to induce chemotaxis and apoptosis. We conclude that toxaphene induces chemotaxis and apoptosis via ROS and that caspases and ROS are involved in the degradation of cytoskeletal proteins.

Interactive dysmorphogenic effects of toxaphene or toxaphene congeners and hyperglycemia on cultured whole rat embryos during organogenesis

Both diabetes mellitus and exposure to environmental contaminants are becoming health hazards to many indigenous populations in the world. In earlier work, we established the embryopathy of the chlorinated pesticide, toxaphene technical mixture (TOX) and its two physiologically most important congeners, T(2) (2-exo,3-endo,5-exo,6-endo,8,8,10,10-octachlorobornane) and T(12) (2-exo,3-endo,5-exo,6-endo,8,8,9,10,10-nonachlorobornane). In this study, the combined effects of toxaphene or its two congeners and high glucose concentrations were studied using rat embryo culture in order to investigate the potential interactions between hyperglycemia and toxaphene exposure. Whole rat embryos (0-2 somite) were explanted and cultured into a normal (8 mM) or hyperglycemic 12.5 mM (12.5 G) or 18.75 mM (18.75 G) culture medium containing TOX, T(2), or T(12) at various concentrations (0, 100, 1000, 5000 ng/ml) for 48 h at 37 degrees C. All treatments, except mild hyperglycemic exposure (12.5 G), had significant adverse effects on the total morphological score, head and crown-rump length, yolk sac diameter and yolk sac circulation. Embryos exposed to 18.75 G did not show malformations but when hyperglycemia at 18.75 G was combined with higher doses of TOX or T(2) synergistic effects on the incidence of neural tube defects were observed. The embryos cultured with T(12) under severe hyperglycemic conditions of 18.75 G showed an inhibition of T(12)-induced neural tube defects, but there was a concurrent underdevelopment of forelimbs or hindlimbs at the highest T(12) dose. The results suggest that there is a site-specific and dose-related interactive dysmorphogenesis elicited by TOX or its congeners with high levels of glucose on rat embryonic development. Because of the relatively high TOX doses used in this study, the drastic growth retardation and malformation observed are unlikely to be observed in human populations. More subtle effects, however, may not be ruled out.

Organochlorines in egg samples from Norwegian birds of prey: congener-, isomer- and enantiomer specific considerations

The content of chlorinated persistent organic pollutants was determined in a total of 44 egg samples from 8 different raptor species collected throughout Norway in the period 1991-1997. The content of 8 chlorinated bornanes, 9 chlorinated pesticides, and 15 polychlorinated biphenyl congeners (PCB) were determined. The highest average concentrations for PCB were found for eggs from White-tailed Sea Eagle and Peregrine Falcon (average sum PCB concentration: 8.9 and 9.1 microg/g wet weight (w.w.), respectively). Merlin and Sparrowhawk eggs were the highest contaminated with chlorinated pesticides (average sum pesticide concentration: 3.0 and 4.3 microg/g w.w.). For the first time, the content of chlorobornanes was determined in Norwegian birds of prey eggs. However, only minor contamination compared to PCBs and conventional chlorinated pesticides was found. The highest sum concentration was determined for White-tailed Sea Eagle eggs (0.09 microg/g w.w.). No chlorobornane contamination was found in Osprey and Merlin eggs. No spatial and regional specific trends or pattern distribution were found for organochlorine contamination in the egg samples analysed. In order to gain information about enantiomer specific bioaccumulation and biotransformation capacity of the organism, enantioselective analyses was performed for the chiral contaminants trans-chlordane, oxy-chlordane and the chlorobornane B9-1679 (Parlar #50). Indications for species-dependent deviation from the racemic distribution (enantiomeric ratio = 1) were found. Peregrine Falcon and Merlin eggs were characterised with an extremely high enantiomeric excess of the (-)-trans-chlordane (enantiomeric ratio (ER) <0.01). For Golden Eagle, Goshawk and Sparrowhawk eggs, the ERs were between 0.1 and 0.22 demonstrating also here that the (-)-trans-chlordane was the most abundant enantiomer. For the distribution of oxy-chlordane and B9-1679 enantiomers no species-dependent differences were found. For all species the ER values between 0.3 and 0.8 were determined. Thus, also for oxy-chlordane and B9-1679, the (-)-enantiomers are the most dominating stereoisomers in the birds of prey eggs analysed.

Study of the enantioselective elimination of four toxaphene congeners in rat after intravenous administration by high resolution gas chromatography negative ion mass spectrometry

This study was performed to investigate the possible enantioselective metabolism of the four chlorinated bornanes: #26, #32, #50 and #62 (according to the Parlar nomenclature) by rats. Rats were exposed to a mixture of these toxaphenes by a single intravenous injection. Enantiomer ratios (ER) as well as the enantiomer fractions (EF) were determined in brain, adipose tissue and liver samples at six time intervals by high resolution gas chromatography (HRGC) coupled to negative ion chemical ionization (NICI) mass spectrometry (MS). Capillaries coated with heptakis-(2,3,6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (TBDMS-CD) or octakis-(2,3,6-tri-O-ethyl)-gamma-cyclodextrin (TEG-CD) were used for the enantioselective separations. Significant time-dependent changes of ER and EF were found in all the three tissues for #26, #50 and #62. Greatest deviations from racemic composition were found in the liver, which is known to be the major metabolizing organ for toxaphenes. #32 was metabolized the fastest, but showed no changes in ER. Brief information is also included about the possible reasons for the different behaviors of the four congeners in the studied tissues.

Man-made chemicals found in remote areas of the world: the experimental definition for POPs

Members of the United Nations Economic Commission for Europe (UN-ECE) signed a legally binding protocol on persistent organic pollutants (POPs) in February 1998 under the Convention on Long-Range Transboundary Air Pollution. A treaty that intends to control the production, import, export, disposal and use of toxic chemicals that persist for decades in the environment has been formally signed at a conference in May 2001 in Stockholm. The 2001 POP treaty, like the 1998 LRTAP POP protocol, contains a provision on adding further chemicals to the initial group of twelve or fifteen. The occurrence of a compound or a group of compounds in so called remote and pristine areas, e.g. in the Artic or in the Southern Hemisphere, proves its stability under the chemical and biological conditions of the environment. Compounds identified in this way, in samples taken primarily in very remote regions of the planet, are classified by their environmental fate and global distribution as persistent organic pollutants (POPs), regardless of any political assessments.