Total toxaphene and specific congeners in fish from the Yukon, Canada

Toxaphene is one of the major persistent organic pollutants with global environmental impacts. We have measured total toxaphene and specific congeners concentrations in 19 fish samples collected from the Yukon, Canada using gas chromatography coupled to ion trap MS/MS. The total toxaphene concentrations ranged from 42 to 242 ng/g (mean = 107+/-61 ng/g). The sum of the three specific congeners (Parlar 26, 50 and 62) was within 10-55 ng/g. The ratio of the sum of the three congeners to the total toxaphene varied between 8% and 25% in the fish samples but the ratio may be species specific. Our results suggest that consumption of these Yukon fish should have minimal risk of toxaphene exposure.     

Can seal eating explain elevated levels of PCBs and organochlorine pesticides in walrus blubber from eastern Hudson Bay (Canada)?

Walrus (Odobenus rosmarus) blubber samples from Inukjuak and Akulivik (East Hudson Bay), Foxe Basin (Igloolik and Hall Beach) and Loks Land (East Baffin Island) were analysed for PCB congeners (ortho and non-ortho substituted) and other persistent organochlorines (DDT, toxaphene, chlordanes, dieldrin, mirex), as well as chlorinated dioxins/furans, to document spatial trends in contaminants in Canadian Arctic marine biota. Samples from 19 of 53 individuals had concentrations of SigmaPCBs greater than 1000 ng g(-1) (wet wt); the remaining individuals had much lower concentrations (50-600 ng g(-1)). Highest concentrations were found in samples from Inukjuak where average concentrations in blubber of females (N = 9) were 1450 +/- 954 ng g(-1) toxaphene, 2750 +/- 1780 ng g(-1) SigmaCHLOR, 2160 +/- 925 ng g(-1) SigmaDDT and 4790 +/- 2380 ng g(-1) SigmaPCB. SigmaPCB and SigmaDDT concentrations greater than 1000 ng g(-1) were unexpected based on previous studies of walrus from Greenland and Alaska. Local contamination was ruled out because levels of all organochlorines were elevated in each animal from Inukjuak, and elevated levels were also found in animals from Akulivik and Loks Land. Walrus from Inukjuak had sigma13C and sigma15N values in muscle intermediate between those of ringed seals (Phoca hispida) and those of walrus from Akulivik with low organochlorine levels. There was a weak but significant correlation between and sigma15N and (log)SigmaPCB. The Inukjuak walrus also had higher proportions of highly chlorinated PCB congeners, and higher DDE/SigmaDDT ratios than walrus from Igloolik or Akulivik. The results suggest that the walrus with elevated organochlorines are feeding at a higher trophic level than those with low levels and are probably utilizing ringed seals for a portion of their diet.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in marine mammals in the Canadian North

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in pooled samples of ringed seal (Phoca hispida) blubber, beluga (Delphinapterus leucas) blubber and polar bear (Ursus maritimus) liver and fat from several areas throughout the Canadian north and compared to mean PCB and HCB levels in the same samples. All seal samples, and all but one polar bear sample, had detectable 2,3,7,8-TCDD at concentrations ranging from 2 to 37 ng/kg, but TCDD was not found in beluga blubber (< 2 ng/kg). All seal samples and one of three beluga samples contained 2,3,7,8-TCDF at levels of 2 to 7 ng/kg, but TCDF was not found in any bear sample. TCDF must therefore be cleared rapidly by polar bears. No other PCDF congeners were found at detection limits of 4 to 8 ng/kg. OCDD concentrations in seal blubber and polar bear samples ranged from not detected (< 8 ng/kg) to 43 ng/kg. No apparent biomagnification of TCDD, OCDD or TCDF occurred from seal to bear fat, similar to previous findings for DDT, and unlike SigmaPCBs and HCB which biomagnified 6- to 17-fold. Highest concentrations of 2,3,7,8-TCDD and OCDD in seals and bears were found in the central Canadian Arctic Archipelago, and lowest were found in Hudson Bay, the reverse of PCB concentration distribution. The reason for higher levels of TCDD and OCDD in the Arctic than in the sub-Arctic is suggested to be trans-polar movement of aerosols with combustion-related origins in Eurasia. Levels of 2,3,7,8-TCDF were more evenly distributed throughout the North, and were positively correlated with PCB, but not with HCB or 2,3,7,8-TCDD levels in seals.     

Organochlorine burdens in blood of ringed and bearded seals from north-western Svalbard.

Ringed seal (Phoca hispida) and bearded seal (Erignathus barbatus) are the main prey of polar bears (Ursus maritimus), and information on organochlorines (OCs) in these pinniped species is important to understand the transport, fate and effects of persistent organic pollutants in the Arctic ecosystem. Thus, OCs were analysed in blood samples of bearded and ringed seals from the coastal ecosystem of the north-western Svalbard archipelago (Kongsfjorden, 78.55degrees N). The relative contribution of OCs could be ranked as follows: Ringed seal females: sigmaPCB > sigma DDT > sigma CHL > sigma HCH > HCB > Mirex. Ringed seal males: sigma PCB > or = sigma DDT > sigma CHL > sigma HCH > or = HCB > Mirex. Bearded seal females: sigma PCB > sigma HCH > or = sigma CHL > sigma DDT > Mirex > HCB. Bearded seal males: sigma PCB > sigma DDT > or = sigma CHL > sigma HCH > Mirex > or = HCB. The concentrations of sigmaPCB and sigma DDT were higher in ringed seals than in bearded seals, whereas sigma HCH was higher in bearded than in ringed seals. In ringed seal females and males sigma PCB was 337 +/- 95 ng/g (n= 6) and 625 +/- 443 ng/g (n=6), whereas sigma DDT was 165 +/- 47 ng/g (n=6) and 621 +/- 559 ng/g (n = 6), respectively. In bearded seal females and males, sigmaPCB was 159 +/- 132 ng/g (n = 6) and 248 +/- 93 ng/g (n = 5), whereas sigmaDDT was 46 +/- 41 ng/g (n = 6) and 161 +/- 71 ng/g (n = 5), respectively. The inter-species differences are caused by a higher trophic position of ringed seals in the Svalbard ecosystem compared to bearded seals. OC levels in ringed seals at Svalbard are similar to those reported from the North-American Arctic and in the lower range compared to previously reported data from Svalbard.     

Levels of toxaphene congeners in fish from Danish waters

The levels of toxaphene congeners, in addition to PCB congeners and organochlorine pesticides, were determined in various fish samples from different Danish waters. While PCB-153 and p,p'-DDE show different levels depending on the fishing area, with highest levels in fish from the Western Baltic Sea, toxaphene was detected in all the samples investigated at a more constant level. The distribution of the three toxaphene congeners Parlar #26, #50 and #62 depends on the fishing area, with the Western Baltic Sea being different from the other waters by having almost equal levels of toxaphene congeners #26 and #50.     

Geographical variation of persistent organochlorine concentrations in blubber of ringed seal (Phoca hispida) from the Canadian Arctic: univariate and multivariate approaches

Geographical variation of organochlorine (OC) concentrations in ringed seal (Phoca hispida) in the Canadian Arctic was studied using univariate and multivariate statistical techniques. The dataset consisted of 80 individual OC components (58 PCB congeners plus DDT- and chlordane (CHL)-related compounds, toxaphene, hexachlorocyclohexanes (HCH), chlorobenzenes (CBz), and dieldrin) determined in 221 ringed seal blubber samples from 13 locations throughout the Canadian Arctic from the period 1983 to 1989. Mean concentrations of the major OC groups in ringed seal blubber (SigmaPCBs, SigmaDDT, SigmaCHL and toxaphene), adjusted for the age and sex of the seals, showed few significant geographical differences. Principal components analysis was used to examine geographical trends. Significant differences in mean factor scores for three of four principal components were found between sampling locations. Locations in the western and high Arctic could be distinguished from those in Hudson Bay by highest scores along principal component two which was associated principally with CBz. PCB congeners with six or more chlorine substitutions declined with increasing north latitude, whereas more volatile OCs (CBz, HCH, less chlorinated PCBs) increased in the proportion of total OCs with latitude. Proportions of less chlorinated PCBs also decreased with increasing longitude, whereas slopes of regressions for more highly chlorinated PCBs increased significantly. The results were generally consistent with the 'cold condensation' hypothesis of increasing proportions of more volatile OCs with increasing latitude and distance from sources.     

Persistent chlorinated pesticides and polychlorinated biphenyls in selected fish species from Lake Tanganyika, Burundi, Africa

Concentrations of selected organochlorine pesticides and PCBs in seven fish species (cichlids) from the north end of the Lake Tanganyika, Burundi, Africa were determined. Results were compared to previous work on the Lake Tanganyika and other water bodies and to the European Community maximum residue levels (MRLs) in edible fat. The analytical method included a hot Soxhlet extraction with a mixture of acetone: hexane (1:3, v/v), gravimetrically lipid determination, and a single step clean-up. For PCBs and stable pesticides, the clean-up was done on activated silica gel impregnated with concentrated sulfuric acid, while for non acid-stable pesticides superposed layers of alumina, silica and florisil impregnated with 15% methanolic solution of KOH were successively used. Recoveries of organochlorine pesticides from certified reference material (CRM 430) were ranging from 86% for p,p'-DDT to 107% for endrin, while recoveries from blank fat spiked fortified at three different levels were between 65% for alachlor at the lowest fortification level and 107% for mirex at the highest fortification level. The limits of detection for each analyte were ranging from 0.1 ng/g to 0.5 ng/g fat. All chlorinated pesticides were found in the analyzed species but at low concentrations. Boulengerochromis microlepis contained the highest concentrations of HCHs (288.2 +/- 15.5 ng/g fat) and DDTs (909.1 +/- 42.5 ng/g fat), while the highest PCB levels (166.7 +/- 37.4 ng/g fat for the sum of 12 congeners) were found in Oreochromis niloticus. However, there is no evidence that Lake Tanganyika is more contaminated with pesticides than other African water bodies.     

Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans and non-ortho substituted biphenyls in polar bear milk from Svalbard (Norway)

Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and non-ortho substituted biphenyls (PCB, CB) were determined in 6 polar bear milk samples from Svalbard (Norway). For these compounds, no data for polar bears have been reported before from this region. Most of the PCDD/PCDF congeners were found at detectable levels. Concentrations expressed as 2,3,7,8-TCDD equivalents (Nordic model) were in the order of 1–3 pg/g⁻¹ fat (0.2–1.6 pg ml⁻¹ milk) which is comparable with ringed and harp seal blubber from the same region. On whole milk basis, concentrations were similar to those found in human milk. An estimation of the daily uptake via milk showed that the intake is lower for polar bears compared to humans. As in human milk, relatively high levels of OCDD were found in some polar bear milk samples. The PCDD/PCDF congener pattern in the milk was different to that found in polar bear fat from the Canadian Arctic. Non-ortho substituted PCB levels in polar bear milk were similar to those found in polar bear fat from the Canadian North. However, CB 77 or 169 dominated in the milk while CB 126 was the most abundant congener in fat. PCDD/PCDF levels expressed as 2,3,7,8-TE were highly correlated with the fat content of the milk. No correlation between CB and PCDD/PCDF concentrations was found. Some data indicate that PCDD/PCDF concentrations in polar bear milk decrease with increasing time after delivery.     

Development and calibration of epiphytic lichens as saltfall biomonitors--dry-deposition modelling

Blubber collected from beluga whales and ringed seals during subsistence hunts in the southern Baffin Island region of the Canadian Arctic were analysed for polychlorinated naphthalenes and eight planar PCB congeners (mono-ortho PCBs: 105, 114, 118 and 156; non-ortho PCBs: 77, 81, 126, 169). SigmaPCN (3-7 Cl) concentrations in blubber ranged from 35.9-383 pg/g (lipid weight; lw) in beluga and 35.4-71.3 pg/g (lw) in ringed seal. These represent the first measurements of PCNs in marine mammals in the Canadian Arctic, mammals which are an important part of the traditional diet of the indigenous population. SigmaCoplPCB concentrations were much higher, ranging from 15.5-317 ng/g (lw) in beluga whale blubber and 16.5-40.9 ng/g (lw) in ringed seal blubber. PCNs and coplanar PCBs both exhibit dioxin-like toxicity. Although average sigmaPCN concentrations were less than 1% of sigmaCoplPCBs, PCNs contribute up to 11% of TEQ relative to the coplanar PCBs based on TEFs determined by H4IIE enzyme assays.     

Some heavy metals, essential elements, and chlorinated hydrocarbons in polar bear (Ursus maritimus) at Svalbard

During the period 1978-1989, samples of liver, kidney and subcutaneous fat from 24 polar bears, Ursus maritimus, from Svalbard were analysed for mercury, cadmium, lead, copper, zinc, selenium, arsenic, HCB, DDE, PCBs (as Aroclor 1260 or Phenoclor DP6). In a selected number of liver (seven) and fat (three) samples, the composition of individual PCB congeners was studied by comparison with 23 individual PCB congeners (IUPAC nos 28, 52, 74, 101, 99, 110, 149, 118, 114, 105, 153, 141, 138, 187, 128, 183, 156, 157, 180, 170, 194, 206 and 209). In the seven liver samples, the concentrations of o,p'- and p,p'-isomers of DDT, TDE, DDE, alpha-, beta- and gamma-HCH, oxychlordane, heptachlor, heptachlorepoxide, aldrin and dieldrin were also determined. The hepatic concentrations of mercury, cadmium and lead in animals of all ages were 0.4-6.0, <0.1-1.2, and <0.5-1.6 microg g(-1), respectively. This indicates a moderate exposure. Concentrations of mercury and selenium were correlated (r=0.80). The levels of copper and zinc represented normal physiological concentrations. The concentrations of HCB, DDE and PCBs in fat were <0.05-1.5, <0.1-3.4 and 2.9-90 microg g(-1), respectively. The corresponding results for liver were <0.01-0.11, <0.1-0.5 and 0.1-78 microg g(-1), respectively. Six PCB congeners, PCB-99, -153, -138, -180, -170, and, -194 accounted for about 99 and 87% of the total PCB content (sum of the 12 congeners, nos. 28, 99, 153, 138, 128 + 187, 156, 157, 180, 170, 194, 206 and 209) in liver and fat, respectively. PCB-153 represented 37+/-3 30+/-16% of the sum PCB (sum of 12 congeners) in liver and fat, respectively. The range of the hepatic concentration of oxychlordane was 5-19 microg g(-1). Quantifiable concentrations of heptachlor, heptachlorepoxide, beta-HCH and dieldrin were also found in all the liver samples analysed. Low concentrations of p,p'- and o,p'-DDT were found in two of seven liver and two of two fat samples. Comparisons are made with investigations from Canada and Greenland. Possible effects of PCBs, especially on reproduction, cannot be excluded. Ringed seal, Foca hispida, and to some extent bearded seal, Erignathus barbatus, are the main food of the polar bear. It is therefore likely that the exposure to environmental pollutants occurs via the consumption of these two species.     

Polychlorinated dibenzo-p-dioxins,dibenzofurans and polychlorinated biphenyls in polar bear,penguin and south polar skua

Concentrations of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (DFs) and non- and mono-ortho-substituted polychlorinated biphenyls (dioxin-like PCBs) were measured in livers of polar bears from the Alaskan Arctic and in eggs of Adelie penguin and south polar skua and weddell seal liver, fish and krill from Antarctica. This is one of the first reports to document the concentrations of PCDDs/DFs in polar bear livers from Alaska, and in penguin and skua eggs from Antarctica. Concentrations of total PCDD/DFs in livers of polar bears ranged from 8 to 66 (mean: 26) pg/g, on a lipid weight basis. Concentrations of total PCDD/DFs in Antarctic samples were in the increasing order on a lipid weight basis; weddell seal liver (8.9 pg/g) < fish (11-17 pg/g) < krill (27 pg/g) > penguin eggs (30 ng/g) > seal liver (57 ng/g) > fishes (6.2 ng/g) > krill (0.9 ng/g). Concentrations of 2378-tetrachlorodibenzo-p-dioxin equivalents (TEQs) calculated based on the WHO TEFs were higher in the eggs of polar skua (mean: 344: range: 220-650 pg/g, lipid wt.) from Antarctica than in polar bear livers from Alaska (mean: 120; range: 69-192 pg/g). In general, concentrations of PCDFs were greater than those of PCDDs in polar organisms. 23478-PeCDF is one of the dominant congener found in several samples. Concentrations of TEQs in polar bear livers and skua eggs were close to those that may cause adverse health effects. Dioxin-like PCBs, particularly, non-ortho coplanar PCBs were the major contributors to TEQ concentrations in penguin and skua eggs whereas mono-ortho PCBs accounted for a major portion of TEQs in polar bear livers.     

Levels and congener pattern of PCBs in arctic fox, Alopex lagopus, in Svalbard

Levels and congener pattern of polychlorinated biphenyls (PCBs) were determined in samples of subcutaneous fat and liver from 27 polar foxes, Alopex lagopus, caught in Svalbard during the winter 1983-1984. In all the samples analysed the composition of individual PCB congeners was studied by comparison with 12 individual PCB congeners (IUPAC nos. 28, 52, 101, 118, 138, 153, 170, 180, 183, 194, 206 and 209). In addition, the PCB congeners nos. 99, 105, 114, 156 and 157 were determined in the fat samples. In both liver and fat samples the sum PCB was calculated based on the concentrations of seven selected congeners, nos. 138, 153, 170, 180, 194, 206 and 209. These congeners were the same as those used in a corresponding investigation made on arctic fox from Svalbard 10 years earlier. The present study reveals that the PCB levels in arctic fox in Svalbard are high and essentially unchanged in the period from 1973-1974 to 1983-1984. The mean sum PCB levels in fat and liver were 8.3 +/- 11 and 0.4 +/- 0.4 microg g(-1), and the extractable fat was 81.2 +/- 8.4 and 4.5 +/- 1.7% for the two tissues, respectively. In fat, sum PCB ranged from 0.5 to 41.0 microg g(-1). PCB nos. 153 and 180 accounted for approximately 65% of sum PCB. The contributions of PCB nos. 138 and 153 to the sum PCB were found to increase from 1974 to 1984. The PCB congener pattern is similar to that found in polar bears, and is dominated by a few congeners (99, 138, 153, 170, 180 and 194). No significant differences in PCB levels were found between sexes or between age groups. However, significantly higher PCB levels were found in old animals (>/= 3 years) with less than 2 cm of fat on the ramp as compared with young animals (1-2 years) with more than 2 cm of fat on the rump. Effects on vital functions from the observed levels of PCBs cannot be excluded for the most contaminated foxes.     

First study of congener group patterns and concentrations of short- and medium-chain chlorinated paraffins in fish from the North and Baltic Sea

This study presents the first investigation of concentrations and congener group patterns of short- (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in fish from the North and Baltic Sea. North Sea dab, cod and flounder were studied. High resolution gas chromatography (HRGC) coupled to low resolution mass spectrometry (LRMS) in the electron capture negative ionization mode (ECNI) was employed. Good linearity (R2>0.993, 7 measuring points) was achieved between 1 and 100 ng/g of CP mixtures for SCCPs and MCCPs. The limits of detection were 0.5-1 ng/microl of CP mixture for the major congener groups of SCCPs and MCCPs. A clean-up comprising fat extraction, adsorption chromatography on silicagel impregnated with concentrated sulphuric acid and adsorption chromatography on Florisil was employed to avoid interferences from other polychlorinated compounds. Recoveries of CPs in spiked samples ranged between 80% and 100%. Accuracy was controlled with spiked samples and deviated not more than 10% from the expected values. Quantification was performed with standards of an average chlorine content as close as possible to that of the samples (SCCPs: 59-62%, MCCPs: 53-58%). SCCP concentrations ranged between 19 and 286 ng/g liver wet weight (ww), MCCP concentrations were comparable with a range of 25-260 ng/gww. Congener group patterns were also determined and discussed. In samples from the Baltic Sea the SCCP congener pattern was similar to that of commercial SCCP mixtures or C13 congeners were most abundant. In samples from the North Sea a higher relative abundance of C10 congeners was observed.     

Polychlorinated biphenyl (PCB) congeners and chlorinated pesticides in a cod liver oil reference material

A cod liver oil reference material, Standard Reference Material (SRM) 1588, which was issued by the National Institute of Standards and Technology (NIST) in 1989, has certified concentrations for five polychlorinated biphenyl (PCB) congeners and ten chlorinated pesticides. Recently, this SRM has been extensively characterized by additional analyses at NIST and by analyses at the Canadian Wildlife Service (CWS) where the SRM was used as a control sample during routine analyses of wildlife tissue specimens. In this paper the results from NIST and CWS are compared and the concentrations for over 40 PCB congeners and 20 chlorinated hydrocarbons are reported.     

Vertical fluxes and accumulation of PCBs in coastal sediments of the Río de la Plata estuary, Argentina

Settling particles and underlying sediments collected at 1, 2.5 and 4 km along offshore transects in the urbanized sector of the Río de la Plata were analyzed to evaluate the sources and accumulation of PCBs. Total PCB concentrations range from <0.1 to 100 ng g(-1) and include variability associated to North-South and offshore gradients reflecting the impact of coastal discharges. Highest concentrations were recorded in the industrialized Central area close to Buenos Aires (61+/-37 ng g(-1) at 1 km) relative to cleaner northern stations (3.6+/-2.2 ng g(-1)) and southward sites (37+/-2.8 ng g(-1)), affected by transport of particulate PCBs by coastal currents. Sediment traps deployed in the Central area revealed large depositional fluxes of total matter (361+/-124 gm(-2)day(-1)) and PCBs (26+/-19 microg m(-2)day(-1)) and high sedimentation rates (5.0+/-1.7 cm yr(-1)). Uniform PCB concentrations (66-89 ng g(-1)) down to 20 cm in sediment cores suggest continued PCB discharges during the last 4 years. PCB composition was dominated by hexa (43+/-6.4%), hepta (23+/-5.1%) and pentachlorobiphenyls (21+/-5.5%) with lower proportions tri-tetra (7.4+/-5.4%) and higher chlorinated congeners (5.1+/-3.3%). A consistent weathering pattern with loss of 3-5 chlorobiphenyls and enrichment in higher chlorinated PCBs corresponding to a shift from a 1:1 to a 1:3 1254:1260 Aroclor mixture, was observed offshore. A principal component analysis performed with the relative contribution of PCB congener classes confirmed the offshore weathering pattern indicating that transformer oils containing Aroclor 1254-1260 are the most probable sources. Sediment inventories, sediment trap fluxes and Fugacity II calculations indicate an accumulation approximately 500-800 kg PCB in superficial sediments of this coastal environment.     

The role of biotic and abiotic degradation processes during the formation of typical toxaphene peak patterns in aquatic biota.

Toxaphene residues in cod liver and fish oil samples from different countries have been analyzed by HRGC-ECD and HRGC-MS as well as with multidimensional gas chromatography. The results have been compared to patterns obtained by photolysis and microbial degradation of selected single chlorobornanes and technical toxaphene. Enantiomeric ratios of the components Parlar #44 and #62 showed significant deviations from 1, indicating metabolism in cod fish and perhaps other species at least for some congeners. Parlar #50 was found to be a racemate, which corresponds to its known stability under biotic and abiotic conditions.     

Pesticides and PCBs in sediments and fish from the Salton Sea, California, USA

The Salton Sea, the largest manmade lake in California, is officially designated by the State of California as an agricultural drainage reservoir. The purpose of this study was to determine organochlorine and organophosphorous pesticides, as well as polychlorinated biphenyl (PCB) concentrations in sediments and fish tissues in the Salton Sea and evaluate the relative ecological risk of these compounds. Sediment samples were taken during 2000-2001 and fish tissues (Tilapia mossambique, Cynoscion xanthulu) were collected in May 2001. All samples were analyzed for 12 chlorinated pesticides, 6 organophosphorus pesticides, and 55 polychlorinated biphenyl (PCB) congeners. SigmaDichlorodiphenyltrichloroethane (SigmaDDT) and total PCB concentrations observed in sediments ranged from 10 to 40 and 116 to 304 ng/g dry wt, respectively. DDT/DDD ratios in sediments and fish tissues of the northern Sea in 2001 indicated recent DDT exposure. Lindane, dieldrin, dichlorodiphenylethane (DDE) and total PCB concentrations detected in sediments exceeded probable effect levels established for freshwater ecosystems, and pp-DDE and total PCB concentrations were higher than effect range-median values developed for marine and estuarine sediments. In fish liver, concentrations of endrin and SigmaDDT exceeded threshold effect level established for invertebrates. SigmaDDT concentrations detected in fish tissues were higher than threshold concentrations for the protection of wildlife consumers of aquatic biota. DDE concentrations in fish muscles tissues were above the 50 ng/g concentration threshold for the protection of predatory birds. Dimethoate, diazinon, malathion, chlorpyrifos, disulfoton varied from < or = 0.15 to 9.5 ng/g dry wt in sediments and from < or = 0.1 to 80.3 ng/g wet wt in fish tissues. Disulfoton was found in relatively high concentrations (up to 80.3 ng/g) in all organs from Tilapia and Corvina. These results demonstrate continued contamination of specific organochlorine compounds in sediments and resident fish species of the Salton Sea.     

Serum PCBs and organochlorine pesticides in Slovakia: age, gender, and residence as determinants of organochlorine concentrations

We measured organochlorine concentrations of 15 polychlorinated biphenyl congeners and six organochlorine pesticides (PCB28, 52, 101, 123(+149), 118, 114, 153, 105, 138(+163), 167, 156(+171), 157, 180, 170, 189, alpha-, beta-, gamma-HCH, HCB, p,p'-DDT and p,p'-DDE) in 2047 subjects from contaminated and background areas of eastern Slovakia. Data were collected in 2001 and analyzed by high-resolution gas chromatography with electron capture detection in 2002-2003. Elevated levels persist in subjects from Michalovce district, site of former production facility, after almost 20-years since the end of the PCB manufacturing. Sum of 15 PCB congeners was 3105 ng/g of lipid in the Michalovce district versus 871 ng/g of lipid for subjects from the background districts of Svidnik and Stropkov. Relatively high concentration in children from the Michalovce district, sum PCB = 766 ng/g of lipid versus 372 ng/g of lipid in children from background area suggest ongoing exposure from environmental reservoirs and contaminated food. Consistent differences between genders in both contaminated and background areas are reported here. Levels in males are about 20% higher in both districts. Levels of organochlorine pesticides, particularly of DDT metabolite DDE and hexachlorobenzene are also elevated in the Michalovce district, reflecting intensive use of pesticides in agriculture in the past. About 30% decrease in serum organochlorine levels was observed in comparison with our earlier samples collected in 1998. These results suggest that contamination with PCBs still remains a source of relatively high environmental exposure for subjects in the Michalovce district.     

Discrimination and thermal degradation of toxaphene compounds in capillary gas chromatography when using split/splitless and on-column injection

Technical toxaphene and a 22-component Reference Mixture were analyzed using capillary gas chromatography with split/splitless injection (SSL) and on-column injection (OC). In both techniques, electron-capture, negative ionization mass spectrometry (ECNI-MS) was used for detection of chlorobornanes, chlorocamphenes and related compounds. Significant discrimination of highly chlorinated congeners was observed as a result of incomplete transfer of these compounds from the vaporizer to the analytical column when using SSL. This resulted in a much lower response for nona- and decachloro congeners than when using OC. In addition, several toxaphene components, especially the chlorobornanes with gem dichloro substitution on the six-member carbon ring, undergo thermal degradation when using SSL. Some of these congeners are major components of technical toxaphene, but generally are not present, except at low concentrations, in environmental and biological samples. Therefore, technical toxaphene may be discriminated and/or degraded differently than toxaphene compounds in environmental samples when using SSL. This results in significant bias of the quantitative data when using the technical material as a reference. OC suffers much less from these deficiencies and, therefore, is a preferable technique for toxaphene analysis.     

Distribution and levels of eight toxaphene congeners in different tissues of marine mammals, birds and cod livers

Levels and distribution of eight compounds of technical toxaphene (CTTs) were determined in different marine species (seals, cetaceans, birds, and fish). The eight CTTs included six commercially available and two chlorobornanes prepared in our lab. These congeners were present in all investigated samples. In agreement with earlier studies, the octachlorobornane B8-1413 (P-26) and the nonachlorobornane B9-1679 (P-50) were the most abundant congeners in most of the samples. In seal blubber, B8-1413 (P-26) and B9-1679 (P-50) contributed with up to approximately 80% (Weddell seal) to the sum of the eight CTTs. In seals from the northern hemisphere the nonachlorobornane was more abundant while in those from the southern hemisphere (Antarctic and Namibia), the octachlorobornane B8-1413 (P-26) usually appeared at higher concentrations. Depending on the species the contribution of the other congeners varied significantly. B9-1025 (P-62) ranged from 2-20%, B8-1412 was found at 4-25% with highest contribution in birds, and B8-2229 (P-44) was found at 5-15%. The remaining three congeners B7-1453, B8-1414 (P-40), and B8-1945 (P-41) were lower abundant except B8-1414 (P-40) which was found at high contribution in liver and kidney of birds. The sum of the eight CTTs ranged from 4 microg/kg to 1.4 mg/kg, depending on the species and region. In most of the seal blubber samples, PCBs and DDT were more abundant (factor 2-20) but Antarctic Weddell seals showed higher CTT levels than PCBs and DDT.