PCB Congeners Research Articles

Associations between vitamins A and E and legacy POP levels in highly contaminated Greenland sharks (Somniosus microcephalus)

The Greenland shark (Somniosus microcephalus) is a top predator in Arctic marine ecosystems, and the species bioaccumulates high levels of biomagnifying persistent organic pollutants (POP). In teleost fish, as well as in marine mammals and seabirds, legacy POP have been shown to interfere with the vitamin A and vitamin E homeostasis. Thus, there is the potential for negative health effects from these legacy compounds in Greenland sharks. In the present study we examined associations among plasma levels of legacy POP and plasma vitamin A (retinol [RET], retinyl palmitate [RPA]) and vitamin E (α-tocopherol [α-TOC]) in Greenland sharks from Svalbard, Norway. Plasma levels of POP were on average higher than the hepatic levels previously reported in Greenland sharks from Iceland and Davis Strait, Canada. Levels were also higher than the plasma levels reported in Arctic marine mammals. DDTs (mean 8069ng/g l.w., range: 900–59,707ng/g l.w.), PCBs (mean 5766ng/g l.w., range 1344–16,106ng/g l.w.) and chlordanes (mean 1551ng/g l.w., range: 323–5756ng/g l.w.) had the highest concentrations among the POP groups studied. There were significant inverse relationships between RET concentrations and the concentrations of the dioxin-like compounds PCB-118 and PCB-156/171, and the non-dioxin-like compounds PCB-99 and PCB-128. There were also significant inverse relationships between RPA and 18 of the 38 POP compounds measured. Furthermore, there were significant positive associations between α-TOC and 13 of the 27 PCB congeners. The study suggests that these vitamin systems can be affected by the relatively high POP concentrations exhibited by Greenland sharks at Svalbard. However, the present study is correlative and thus the potential interplay between POP and vitamin dynamics of Greenland sharks must be interpreted cautiously, pending further research on this issue among elasmobranchs.

Genetic susceptibility to dioxin-like chemicals’ induction of cytochrome P4501A2 in the human adult linked to specific AhRR polymorphism

BackgroundDioxin-like chemicals are known to exert their effect by binding to aryl hydrocarbon receptor (AhR), forming complexes with aryl hydrocarbon nuclear translocator (ARNT), and binding to dioxin responsive elements (DREs) in promoter region to regulate the transcription of specific genes. In a previous study of the Yucheng cohort of humans who were exposed to high toxic levels of dioxin-like chemicals (PCDFs and PCBs), we reported marked induction of cytochrome P450 1A2 (CYP1A2) activity and this induction was an excellent biomarker of the exposure and adverse human health effects seen in the Yucheng cohort. ObjectivesThe goal of this study was to determine the relationship between inducibility of CYP1A2 and genetic polymorphisms of AhR, ARNT, and AhRR in human. MethodsThe Yucheng victims who completed blood sample collecting in 1994–1995 for serum concentrations of PCB, PCDF, and PCDD congeners, and also completed the caffeine breath tests for CYP1A2 activity were identified. From the collected blood samples, six single nucleotide polymorphisms were selected for genotyping, including AhR (rs2066853), AhRR (rs2292596), ARNT (rs7517566), ARNT (rs3820541), ARNT (rs3768016), and ARNT (rs2228099). ResultsAhRR (rs2292596) polymorphism was significantly related to CYP1A2 inducibility (p=0.01). A linear trend test was observed between people with AhRR (rs2292596) GG, GC, and CC genotype (p=0.0014). ConclusionOverall, AhRR (rs2292596) genotypes predict the inducibility of CYP1A2 in people highly exposed to toxic dioxin-like chemicals. Future studies and analysis will determine to what degree these polymorphisms can predict a human’s susceptibility to dioxin-related adverse human health effects.

Passive Sampling to Measure Baseline Dissolved Persistent Organic Pollutant Concentrations in the Water Column of the Palos Verdes Shelf Superfund Site

Passive sampling was used to deduce water concentrations of persistent organic pollutants (POPs) in the vicinity of a marine Superfund site on the Palos Verdes Shelf, California, USA. Precalibrated solid phase microextraction (SPME) fibers and polyethylene (PE) strips that were preloaded with performance reference compounds (PRCs) were codeployed for 32 d along an 11-station gradient at bottom, surface, and midwater depths. Retrieved samplers were analyzed for DDT congeners and their breakdown products (DDE, DDD, DDMU, and DDNU) and 43 PCB congeners using GC-EI- and NCI-MS. PRCs were used to calculate compound-specific fractional equilibration achieved in situ for the PE samplers, using both an exponential approach to equilibrium (EAE) and numerical integration of Fickian diffusion (NI) models. The highest observed concentrations were for p,p'-DDE, with 2200 and 990 pg/L deduced from PE and SPME, respectively. The difference in these estimates could be largely attributed to uncertainty in equilibrium partition coefficients, unaccounted for disequilibrium between samplers and water, or different time scales over which the samplers average. The concordance between PE and SPME estimated concentrations for DDE was high (R(2) = 0.95). PCBs were only detected in PE samplers, due to their much larger size. Near-bottom waters adjacent to and down current from sediments with the highest bulk concentrations exhibited aqueous concentrations of DDTs and PCBs that exceeded Ambient Water Quality Criteria (AWQC) for human and aquatic health, indicating the need for future monitoring to determine the effectiveness of remedial activities taken to reduce adverse effects of contaminated surface sediments.

Polychlorinated biphenyls and their hydroxylated metabolites in wild fish from wheatley Harbour Area of Concern, Ontario, Canada

Whole-body polychlorinated biphenyls (ΣPCBs) and plasma hydroxylated PCBs (OH-PCBs) concentrations were determined in brown bullhead (Ameiurus nebulosus) from Wheatley Harbour, Ontario, Canada. Elevated ΣPCBs in Wheatley Harbour are suspected to have originated from industrial waste disposal and/or discharges from nearby fish processing through discarding of fish remains. Mean ΣPCB concentrations in brown bullhead from Wheatley Harbour were approximately 250 ng/g wet weight compared with approximately 40 ng/g wet weight for brown bullhead from the reference sites, Hillman Marsh and Turkey Creek (both in Ontario, Canada). A significant relationship was found between the concentrations of non-ortho and mono-ortho PCB concentrations (toxic equivalents) and liver mixed-function oxygenase in brown bullhead (r = 0.74, p < 0.001). Plasma OH-PCB concentrations were greater in Wheatley Harbour brown bullhead than in those from Hillman Marsh (3.6 vs 1.5 ng/g wet wt, p < 0.01), and were detected infrequently in those from Turkey Creek (0.1 ng/g wet wt, n = 2). The OH-PCB congeners most frequently detected were 4'-OH-CB172, 3'-OH-CB180, 4-OH-CB187, 4-OH-CB146, 3-OH-CB138, and 4-OH-CB130, which are structurally similar to the thyroid hormones. To test the hypothesis of fish waste as the cause of the observed PCB contamination of Wheatley Harbour brown bullhead, a principal component analysis (PCA) was used to compare the brown bullhead PCB congener data with equivalent data for Lake Erie walleye, Lake Erie sediment, and industrial Aroclor mixtures. The relative proportions of each Aroclor mixture were estimated using the conjugated gradient method. The high similarity between the congener signatures for Lake Erie walleye and Wheatley Harbour brown bullhead supports the hypothesis of contamination from the fish processing industry.

Three decades (1983–2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 1: Legacy organochlorine contaminants

Legacy organochlorine contaminants were determined in adipose tissues from 294 polar bears (Ursus maritimus) sampled in East Greenland in 23 of the 28years between 1983 and 2010. Of 19 major legacy contaminants and congeners (ΣPCB, 4 PCB congeners (CB153, 180, 170/190), ΣDDT, p,p′-DDE, p,p′ -DDD and p,p′-DDT, α- and β-hexachlorocyclohexane (HCH), HCB, octachlorostyrene, dieldrin, oxychlordane, cis- and trans-chlordane, cis- and trans-nonachlor, heptachlor epoxide and BB-153), 18 showed statistically significant average yearly declines of −4.4% (range: −2.0 to −10.8%/year) among subadult polar bears (i.e. females<5years, males<6years). For example, the ∑PCB concentrations declined 2.7 fold from 22730ng/g lw (95% C.I.: 12470–32990ng/g lw) in 1983–1986 to 8473ng/g lw (95% C.I.: 6369–9776ng/g lw) in 2006–2010. Similar but fewer statistically significant trends were found for adult females and adult males likely due to smaller sample size and years. Despite declines as a result of international regulations, relatively high levels of these historic pollutants persist in East Greenland polar bear tissues.

Historical Changes in Polychlorinated Biphenyls Contaminated Sediments

Problem statement: PCBs contamination continues to pose a health risk to aquatic environments due to their recalcitrance and bioaccu mulation. The Sangamo Weston/Twelvemile Creek/Lake Hartwell Superfund Site is an example of such a health risk as a result of PCBs discharged from a former capacitor manufacturing plant. We conducted a study in twelvemile creek (Clemson, SC, USA) to examine the temporal trend of PCB contaminated sediments. Approach: Surface sediments were sampled at four sites in fall 2008 t o compare with concentrations measured in past studies. Total PCBs and congener-specific analyses were performed on Gas Chromatography-Electron Capture Detector (GC-ECD). Results: Total PCB concentrations ranged from 0.026-0.18 �g g -1 , which were one order of magnitude lower than levels measured in 1987 (<0.20-10.23 �g g -1 ). Total PCBs in this study (based on more than 130 congener s) were similar to those observed in 2003-2004 (based on only 20 congeners). PCB congener patterns indicated that PCBs near the source were dominated by lower chlorinated congeners while heavy congeners were persistent further downstream. Conclusion: Physical and biochemical processes such as natural attenuation, mixing/dispersion and PCBs degradation are contributing to the decreasing concentrations after the discharge was eliminated in 1975. The congener pattern shift is likely attri buted to a loss via volatilization and export of contaminated sediment from the stream. Burial could be a potential means to prevent resuspension into the water column.

2,2′,3,5′,6-Pentachlorobiphenyl (PCB 95) and Its Hydroxylated Metabolites Are Enantiomerically Enriched in Female Mice

Epidemiological and laboratory studies link polychlorinated biphenyls and their metabolites to adverse neurodevelopmental outcomes. Several neurotoxic PCB congeners are chiral and undergo enantiomeric enrichment in mammalian species, which may modulate PCB developmental neurotoxicity. This study measures levels and enantiomeric enrichment of PCB 95 and its hydroxylated metabolites (OH-PCBs) in adult female C57Bl/6 mice following subchronic exposure to racemic PCB 95. Tissue levels of PCB 95 and OH-PCBs increased with increasing dose. Dose-dependent enantiomeric enrichment of PCB 95 was observed in brain and other tissues. OH-PCBs also displayed enantiomeric enrichment in blood and liver, but were not detected in adipose and brain. In light of data suggesting enantioselective effects of chiral PCBs on molecular targets linked to PCB developmental neurotoxicity, our observations highlight the importance of accounting for PCB and OH-PCB enantiomeric enrichment in the assessment of PCB developmental neurotoxicity.

Remobilization of polychlorinated biphenyls from sediment and its consequences for their transport in river waters

A laboratory experiment was performed to examine the remobilization of indicator polychlorinated biphenyls (iPCBs) from sediments and its results were applied to the real-world data for explaining the transport of PCBs in river. Seven PCB concentrations were determined in three series of model water–sediment systems (3 g of river sediment, three different volumes of distilled water (0.5, 0.25, and 0.15 ml), and 5 mg of biocide) after 11 days of incubation. Solid-phase extraction was used for separation of analytes from the aqueous phase and solvent extraction for isolation of analytes from the sediments, respectively. The extracts were analyzed for individual iPCB congeners using gas chromatography–mass spectrometry method. For each series of the experiment, the concentrations of PCBs in aqueous phase were similar. The average sediment/water partition coefficient value was 104 l/kg. The solubility of individual PCB congeners in water did not influence the desorption of PCBs from the sediment. Although the dominant form of PCBs in a water–sediment system occurs as suspended and colloidal fractions, these compounds are transported mostly in a dissolved form. Suspended and colloidal matter is a major sink for PCBs in low-energy aquatic environments. In contrast, the dissolved PCBs are readily transported in running waters. The mobilization of PCBs from sediments to aqueous phase, with respect to their solubility in water, seems to be limited, thus reducing the risk of secondary pollution.

Polychlorinated dibenzodioxins, dibenzofurans, and biphenyls in fresh water fish from Campania Region, southern Italy

Twenty-eight fish muscle specimens from the main water bodies of the Campania Region were analyzed in our laboratory. On average, results showed a low contamination by PCDDs+PCDFs and a relatively more important presence of DL-PCBs. All specimens were compliant with EU regulatory maximum levels. Cumulative PCDD+PCDF+DL-PCB concentrations (TEQTOT) were comprised in the range 0.223–11.4 pgWHO97–TEQg−1 fresh weight (fw). DL-PCB contribution to TEQTOT was on average greater than 86% (range, 50.2–97.1%). The cumulative concentrations of 30 non-dioxin-like PCB congeners (Σ30(NDL-PCBs)) and of the six indicators (Σ6(NDL-PCBs)) were respectively in the ranges 3.30–515 and 1.30–195ngg−1fw. The hybrid clustering approach adopted to analyze the sample-specific congener profiles indentified the main analytical patterns present in the database and, in particular, two main diverse exposure macro-areas that seem to exist north and south of the city of Naples. The distribution of PCDD and PCDF congeners among different species showed significant variations from chub (Leuciscus cephalus), characterized by a higher proportion of low-chlorinated congeners (e.g. 2,3,7,8-T4CDD), to eel (Anguilla anguilla), whose contamination consisted mainly of highly chlorinated congeners (e.g. O8CDD). To have a more complete perspective in relation to the contaminants present in the environment, the study suggestion is to use benthic as well as pelagic species to obtain an integrated characterization of fish tissue contamination.

POLYCHLORODIBENZODIOXINS (PCDDs), POLYCHLORODIBENZO-FURANS (PCDFs), AND DIOXIN-LIKE POLYCHLOROBIPHENYLS (DL-PCBs) IN MILK, MOZZARELLA CHEESE, WHEY, AND WHEY CHEESE FROM BUFFALOES RAISED IN THE CAMPANIA REGION

Dioxins (PCDDs and PCDFs) and PCBs are a group of and toxic organo-chlorinated chemicals comprising hundreds of structurally related compounds (congeners) classified as persistent organic pollutants (POPs). It is acknowledged that 17 PCDD and PCDF congeners are of major concern due to their toxicity; 12 PCB congeners are also recognized to express dioxin-like toxicity and are thereby identified as DL-PCBs. Due to their high persistence and lipophilic nature, dioxins and PCBs tend to accumulate in fat and their bio-accumulation through the food chain may pose the risk of causing adverse effects to human health. For the general population, dietary intake is the most important pathway of exposure to the aforesaid environmental contaminants: meat, milk and dairy products, and fish and other seafood products contribute to total daily intake for more than 90 %. To prevent excessive human exposure to dioxins and DL-PCBs, the European Commission established maximum levels for dioxins and the sum of dioxins and DL-PCBs in an array of food components mainly of animal origin (Regulation EC 1881/2006). In this study, dioxins and DL-PCB concentrations were measured in buffalo milk collected from three impounded Campania farms producing milk with different contamination levels. The fate of contaminants in mozzarella cheese, whey, and whey cheese was also investigated. Analyses were carried out by HRGC-HRMS using US EPA Method 1613. The results of this study show the carry-over of the contamination from milk to its dairy products.

Fractionation and current time trends of PCB congeners: evolvement of distributions 1950–2010 studied using a global atmosphere-ocean general circulation model

Abstract. PCBs are ubiquitous environmental pollutants expected to decline in abiotic environmental media in response to decreasing primary emissions since the 1970s. A coupled atmosphere-ocean general circulation model with embedded dynamic sub-models for atmospheric aerosols and the marine biogeochemistry and air-surface exchange processes with soils, vegetation and the cryosphere is used to study the transport and fate of four PCB congeners covering a range of 3–7 chlorine atoms. The change of the geographic distribution of the PCB mixture reflects the sources and sinks' evolvement over time. Globally, secondary emissions (re-volatilisation from surfaces) are on the long term increasingly gaining importance over primary emissions. Secondary emissions are most important for the congeners with 5–6 chlorine atoms. Correspondingly, the levels of these congeners are predicted to decrease slowest. Changes in congener mixture composition (fractionation) are characterized both geographically and temporally. In high latitudes enrichment of the lighter, less persistent congeners and more delayed decreasing levels in response to decreasing emissions are found. The delivery of the contaminants to high latitudes is predicted to be more efficient than previously suggested. The results suggest furthermore that the effectiveness of emission control measures may significantly vary among substances. The trends of decline of organic contaminant levels in the abiotic environmental media do not only vary with latitude (slow in high latitudes), but do also show longitudinal gradients.

Prenatal polychlorinated biphenyl exposure is associated with decreased gestational length but not birth weight: archived samples from the Child Health and Development Studies pregnancy cohort

BackgroundPolychlorinated biphenyls (PCBs), known endocrine disruptors, were banned in 1979 but persist in the environment. Previous studies are inconsistent regarding prenatal exposure to PCBs and pregnancy outcomes. We investigated associations between prenatal exposure to PCBs and gestational length and birth weight.MethodsIn a sample of 600 infants (born between 1960 and 1963) randomly selected from Child Health and Development Studies participants followed through adolescence we measured 11 PCB congeners in maternal post partum sera (within three days of delivery). Length of gestation was computed from the reported first day of the last menstrual period (LMP) and delivery date. Linear regression was used to estimate associations between PCB exposure and gestational age and birth weight, adjusting for potential confounders. PCBs were grouped according to hypothesized biological action (1b (sum of weak phenobarbital inducers), 2b (sum of limited dioxin activity), and 3 (sum of CYP1A and CYP2b inducers)) or degree of ortho- substitution (mono, di, tri). Secondary analyses examined associations between total PCB exposure and exposure to individual congeners.ResultsEach unit increase in mono-ortho substituted PCBs was associated with a 0.30 week decrease (95% confidence interval (CI) -0.59, -0.016), corresponding to a 2.1 (95% CI −4.13, -0.11) day decrease in length of gestation. Similar associations were estimated for di-ortho substituted PCBs, (1.4 day decrease; (95% CI −2.9, 0.1)) and group 3 PCBs (0.84 day decrease; (95% CI −1.8, 0.11). We found similar associations in congener specific analyses and for the sum of congeners.ConclusionsOur study provides new evidence that PCB exposure shortens length of gestation in humans. This may have public health implications for population exposures.

The occurrence and dynamics of polychlorinated hydrocarbons in brown hare (Lepus europaeus) in south-western Slovakia

This study aimed at obtaining the data on the occurrence, levels and correlations of organic pollutants present in game animals (n = 75, Brown hare, Lepus europaeus Pall.) in the region of south-western Slovakia. The analyses performed included dichlorodiphenyltrichloroethane (DDT), hexachlorobenzen (HCB), alpha- and beta hexachlorocyclohexane (α+β-HCH), gamma-hexachlorocyclohexane (γ-HCH), and polychlorinated biphenyls (PCB-delor, commercial mixture of PCB congeners). A gas chromatograph with an electron capture detector was used for the analysis. PCB-delor and DDT were accumulated significantly in the highest level (0.105±0.059 mg/kg; 0.070 mg/kg) in depot fat in brown hares; however maximum permissible limits for the observed pollutants were not exceeded. Significantly higher concentrations of DDT, HCB, γ-HCH, and PCB-delor were found in adult animals when compared with juvenile hares. Gender and season had no effect on the accumulation of observed pollutants. Moderately positive correlation was found between PCB-delor and DDT (r = 0.59). Monitoring of environmental pollution with polychlorinated hydrocarbons is important with regard to public health, as game animals constitute an important part of food chain also for humans.

METHOD OF ANALYSIS VALIDATION OF DIOXIN-LIKE PCB’S IN DAIRY PRODUCT

Dioxin like-polychlorinated biphenyls are unintentionally produced ubiquitous, persistent organic pollutants. The main source of human exposure to the compounds is food of animal origin because bioaccumulation in food chains. Extraction of dairy products by liquid-liquid extraction (LLE) technique for milk but extraction of other dairy products such as cheese was by soxhlet technique. In addition, clean samples after extracting the fat from dairy product samples by three - column chromatographyies, which include multi-layer silica, alumina column and then the third phase of the chromatographic column, is carbon. Method of analysis for determination of “dioxin-like PCBs” -show high toxicological properties that are similar to dioxins - in dairy products by high-resolution gas chromatography/ high-resolution mass spectrometry (HRGC/HRMS). Results were development of reliable and validated analytical method for dairy products, which recognized to be good indicator of environmental exposure for persistent organic pollutants. The method performance was tested for four non-ortho PCB congeners (PCB 77, 81,126, and 169) and eight mono-ortho PCB congeners (105, 114, 118, 123, 156, 157, 167, and 189) with good average recovery (via 13C12-labelled PCB internal standard) of the twelve PCB congeners for dairy products at level 40 ng/kg varies between 99-109 %. The trueness of a measurement method for dioxin like polychlorinated biphenyls in dairy product such as cheese where the results demonstrated satisfaction z-scores within range of ±2 for sum non-ortho-PCB was -0.85, and for sum mono-ortho-PCB -0.74. The reproducibility expressed as relative standard deviation percent was less than 22.6 % and the measured uncertainty including random and systemic error (on 95% confidence level) was less than 40%.

MAIN TRENDS OF CHANGE OF PERSISTENT TOXIC SUBSTANCES CONCENTRATIONS IN BLOOD OF ARCTIC REGION INDIGENOUS POPULATION

To address concerns arising from possible increased human exposure in the Arctic and possible effects of POPs, all circumpolar countries agreed in 1994 to monitor specific human tissues for contaminants in the Arctic under the Arctic Monitoring and Assessment Program. Indigenous volunteers in eight circumpolar countries contributed blood samples that were analyzed for 14 PCB congeners and 13 organochlorine pesticides. The blood concentrations of POPs from the cohort study 2001-2010 were compared. The indigenous people from Chukotka had significantly higher levels of PCBs, hexachlorobenzene, chlordane derivatives alpha-chlordane, beta-hexachlorocyclohexane and lead than the people from the Nenets Autonomous Area (NAA). The level of some DDT and 4.4 DDE concentrations were significantly lower in blood in the NAA after ten years of observations. These differences among groups may represent regional dietary preferences or different contaminant deposition patterns across the Arctic.

Air–soil exchange of PCBs: Seasonal variations in levels and fluxes with influence of equilibrium conditions

The variations in the occurrences of PCB congeners both in soil and air were investigated in conjunction with each other, and the changes in the fugacity fractions and flux levels were examined on a seasonal basis. Air and soil samples were collected concurrently two or three times in a month during a one-year monitoring at two different locations in Bursa, located in the northwestern Turkey. Fugacity fractions and net flux levels of PCB congeners were calculated.Air and soil PCB levels increased together as the soil temperature increased, suggesting the influence of instantaneous air–soil exchange towards the equilibrium conditions. The flux levels and fugacity fractions also showed a positive significant correlation with soil temperature. Flux levels were positive for the dates with fugacity fractions above 0.5, indicating volatilization from soil to air.

Organochlorine contaminants in coastal marine ecosystems of southern Alaska: Inferences from spatial patterns in blue mussels (Mytilus trossulus)

We measured the concentrations and chemical structures of persistent organochlorines (OCs) in blue mussels (Mytilus trossulus) from 44 sites across southwest and southeast Alaska in an effort to determine both the sources of these compounds and the extent to which this region might be contaminated. High PCB concentrations were detected at Amchitka, Adak, and Unalaska Islands (83, 430, and 2800μgkg−1 dry weight, respectively) in the Aleutians with relatively low concentrations elsewhere (7.1–51μgkg−1 dry weight). Heavy PCB congener profiles (indicative of localized point sources) characterized the high concentration sites whereas distinctly lighter congener profiles (indicative of atmospheric transport) characterized the lower concentration sites. Elevated PCB concentrations at Adak were restricted to a small area along the island’s eastern shore, suggesting either limited dispersion or rapid dilution of these compounds. More uniform chlorinated pesticide concentrations among the collection sites suggests that these compounds are entering the Aleutian ecosystem from distant sources. Pesticide concentrations correlated significantly with seabird density across the islands we sampled, thus identifying biological transport as a delivery mechanism of these compounds to the Aleutian archipelago. Our findings do not implicate persistent organochlorines as a significant factor in the recent pinniped and sea otter population declines across southwest Alaska.

Very high correlations between fresh weight and lipid-adjusted PCB-153 serum concentrations: Irrespective of fasting status, age, body mass index, gender, or exposure distributions

Background and aimPersistent organochlorine pollutants (POPs) have in epidemiological studies been associated with health hazards. The exposure window might be crucial and it is, accordingly, important to analyze exposure concentrations in samples collected at the window of interest. This makes the use of stored blood samples extremely interesting. However, small blood volumes from stored samples in biobanks means that the researchers in epidemiological studies most often have to select a limited number of biomarkers representing the POP exposure and abstain from analyses of lipid concentrations. This raises the question of the necessity of lipid adjustment. The aim of the present study was to evaluate the correlation between fresh weight and lipid adjusted concentrations. MethodsWe included data from studies were we have used the PCB congener 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) as a biomarker for POP exposure and where fresh weight as well as lipid adjusted PCB-153 concentrations are known (n=1628). The variety of the cohort members in the different studies gave us the possibility to better understand how well these measures correlate. ResultsWhen all individuals were included in the analyses a correlation coefficient of 0.95 between fresh weight and lipid adjusted serum concentrations was obtained. Restricting the analyses to specific subgroups (based on gender, fasting status, age and BMI) gave correlation coefficients between 0.85 and 0.97. ConclusionsThis study does strongly support the use of samples from biobanks in epidemiological studies for analyzing PCBs, at least regarding PCB-153, even though it is not possible to lipid adjust the results.

Bioaccumulation of six PCB indicator congeners in a heavily polluted water reservoir in Eastern Slovakia: tissue-specific distribution in fish and their parasites

Concentrations of six indicator PCB congeners (IUPAC nos. 28, 52, 101, 138, 153, and 180) were measured in several organs and adipose tissue of a freshwater predatory fishes (European perch, northern pike, pike perch, wels catfish) as well as in nonpredators (common carp, freshwater bream, goldfish, white bream) and in acanthocephalan Acanthocephalus lucii from the water reservoir Zemplínska šírava (Eastern Slovakia), which is considered to be one of the most PCB-contaminated places in Europe. Concentration of PCBs was determined by capillary gas chromatography in samples from May to September 2009. The two-way main-effect ANOVA confirmed that feeding habits of fish (P < 0.00001) and peculiarity of individual fish organs (P < 0.01) affect PCB bioaccumulation. The total amount of PCBs was significantly higher (P < 0.05) in predators compared to nonpredators. Tissue-specific differences were found in PCB accumulation in both fish groups. PCBs were predominantly accumulated in the liver and hard roe. Individual congeners were not distributed homogeneously within the investigated organs and adipose tissue. PCB 153 was present in higher concentrations than the other congeners in all fish organs as well as in adipose tissue comprising an average 31 and 34 % of ΣPCB in predators and nonpredators, respectively. Acanthocephalans, attached to the intestine of perch, absorbed significantly higher concentrations of PCBs (P < 0.001) than the muscles, liver, kidney, brain, and adipose tissue of their host. About 20 times lower amount of PCBs was detected in the liver and almost 3 times in muscles of infected perch. Data on PCB accumulation in perch infected with acanthocephalans demonstrated a decline of PCB values in all organs as well as in adipose tissue compared to noninfected fish. About 20 times lower amount of PCBs was detected in the liver and almost 3 times in muscles of infected perch. Present results could indicate that some parasitic organisms may influence positively their hosts in PCB-contaminated environment.

Influence of Smoking on Indicatory Congeners Residues Levels in Fish Slices

The aim of this study was do determine changes in concentrations of indicatory PCB congeners (IUPAC numbers: 28, 52, 101, 118, 153, 138, 180) during industrial hot smoking of mackerel (Scomber scombrus L.) and herring (Clupea harengus L.) slices and cold smoking of mackerel slices. PCB content in raw mackerel slices averaged from 1.32±0.29 ng/g wet w. for PCB 52 to 4.66±0.72 ng/g wet w. for PCB 153. In herring slices, PCB content ranged from 1.36±0.25 ng/g wet w. for PCB 28 to 16.50±1.94 ng/g wet w. for PCB 153. During hot smoking, losses of the examined compounds were observed - in herring slices by 15% (PCB 153) to 32% (PCB 52), while in mackerel slices by 3.7% (PCB 80) to 38% (PCB 28). Simultaneously, a slight increase in the content of PCB 180, PCB 118, PCB 153, PCB 138 and PCB 101 occurred during the proper smoking, between 1.5ᵗʰ and 2.5ᵗʰ hour of the smoking process. During cold smoking (26°C, 8 h), PCB concentrations increased significantly (p<0.05) by 26% (PCB 28, PCB 138) to 43% (PCB 180). In the final stage of smoking, PCB content in the alder sawdust and in the smoke had a significant effect on the levels of the analysed PCB congeners in the smoked slices. The main parameter determining the change of these compounds contents was their decrease in co-distillation with steam. In the final phase of the hot smoking a little increase of PCB compounds contents was a consequence of their penetration with smoke to the fish meat tissue.