Dioxin and dioxin-like PCB exposure of non-breastfed Dutch infants

The exposure of humans to PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like PCBs (dl-PCBs, i.e. polychlorinated non-ortho and mono-ortho biphenyls) occurs predominantly via the intake of food. Young children have a relatively high intake of these substances, due to their high food consumption per kilogram body weight. As the exposure of non-breastfed infants to these compounds has not been assessed before in The Netherlands, we studied the dietary intake of 17 PCDD/Fs and 11 dioxin-like PCBs in 188 Dutch non-breastfed infants between 4 and 13 months. The food intake of the infants was assessed by a 2-d food record. From these data PCDD/F and dioxin-like PCB intake was calculated using PCDD/F and dioxin-like PCB concentrations of food products sampled in 1998/1999 in The Netherlands. The long-term PCDD/F and dioxin-like PCB exposure of the infants was calculated using the statistical exposure model (STEM). For infants of 5 months the chronic exposure to PCDD/F and dioxin-like PCB was 1.1pg WHO-TEQ (toxic equivalents) per kilogram body weight (bw) per day (95th percentile: 1.7pg WHO-TEQ/kg bwxd), which mainly originated from infant formula and vegetables and increased to 2.3pg WHO-TEQ/kg bwxd (95th percentile 3.7pg WHO-TEQ/kg bwxd) for infants just over 1 year old eating the same food as their parents. The percentage of formula-fed infants with an exposure exceeding the TDI of 2pg WHO-TEQ/kg bwxd was 5% at 5 months, 49% at 9 months and 64% at 12 months.     

Effects of dietary wheat bran on absorption and accumulation of PCBs in rats

Polychlorinated biphenyls (PCBs) are toxic environmental contaminants, which tend to accumulate in the food chain. Since dietary intake is the most important exposure route, PCB body burden may be affected by taking proper dietary measures. In the present study, diets were supplemented with either wheat bran or its cellulose based placebo in order to study the effect of bran consumption on the absorption of dietary PCBs and the excretion of initially stored PCBs. During the period of PCB intake, faecal PCB excretion was elevated by consumption of wheat bran as compared to the placebo. Hence, apparent faecal PCB digestibilities as well as PCB retentions in the whole body were lower in the wheat bran consuming rats. After ending PCB consumption, dietary wheat bran had only a minor effect on faecal PCB output while accumulation in the body was not affected. When PCBs were consumed for a longer time, a small but significant reduction of apparent faecal PCB digestibility was found. However, PCB content in the body kept increasing while PCB retention as percent of intake remained almost constant. Furthermore, differences among individual PCB congeners in metabolic susceptibility and hydrophobic characteristics had an impact on their accumulation in the body.     

Digestibility, retention and incorporation of low-level dietary PCB contents in laying hens

Polychlorinated biphenyls (PCBs) are persistent and hazardous environmental contaminants, which tend to bioaccumulate in the food chain. In the present report the long-term effect of low-level dietary PCB concentrations was studied on performance, egg quality, apparent PCB digestibility, apparent PCB retention and PCB accumulation in laying hens that were fed experimental diets for 41 weeks. The tested dietary concentrations of supplemented PCBs, based on the sum of seven reference congeners, were 0, 1.5 and 6 ng/g. PCB ingestion did not significantly affect performance or egg quality parameters. The PCB concentration in egg yolk reached a nearly constant level after approximately 40 and 70 days of consumption of the diets containing 1.5 and 6 ng PCBs/g, respectively. Apparent faecal PCB digestibility and apparent retention were not influenced by dietary levels of added fat varying between 1.5% and 4.5%, but were significantly higher in hens fed diets containing added PCBs. Moreover, apparent PCB digestibility and retention increased significantly with age. Among the seven individual PCB congeners, no systematically significant differences with regard to apparent faecal digestibility were observed throughout the experiment. Accumulation of PCBs in the fat fraction of egg yolk, abdominal adipose tissue and thigh and breast muscle greatly depended upon PCB intake, but never exceeded the maximally allowed concentration of 200 ng/g. As PCBs 52 and 101 were hardly found in egg yolks and hen tissues, it was concluded that both congeners were greatly metabolised. Comparison of relative contents of individual PCB congeners revealed that PCBs 118, 138 and 153 were preferentially incorporated in yolk and body tissues.     

Background levels of non-ortho-substituted (coplanar) polychlorinated biphenyls in human serum of Missouri residents

This study characterizes the levels of polychlorinated biphenyls (PCB) congeners PCB 77, PCB 81, PCB 126, and PCB 169, in a group of 150 men and women with no documented exposure to PCBs. Its purpose is to provide current referent levels of coplanar PCBs in Missouri residents and to compare those levels to levels reported in the literature from the United States and other countries. Although this study used an extensive questionnaire assessing potential sources of exposure, no positive relations were found between these exposure sources and participants' PCB levels. The PCB levels for the four congeners measured were lower than any reported in the literature. PCBs 126 and 169 are only two of the dioxin-like congeners; however, their contribution makes up 11% of the total TEQ. Age was significantly related to PCB 126 and PCB 169. For every one-year increase in age, both PCB congeners increased by approximately 0.4 parts per trillion (ppt). There was no gender difference for PCB 126; however, PCB 169 levels were 3 ppt higher in males than females.     

Polychlorinated naphthalenes (PCNs) in Irish foods: Occurrence and human dietary exposure

The concentrations of selected polychlorinated naphthalene (PCN) congeners (PCNs 52, 53, 66/67, 68, 69, 71/72, 73, 74 and 75) were determined in 100 commonly consumed foods, in the first study on occurrence of these contaminants in the Republic of Ireland. Congener selection was based on current knowledge on PCN occurrence and toxicology, and the availability of reliable reference standards. The determinations were carried out using validated analytical methodology based on 13C10 labelled internal standardisation and measurement by HRGC-HRMS. The results showed PCN occurrence in the majority of studied foods--milk, fish, dairy and meat products, eggs, animal fat, shellfish, offal, vegetables, cereal products, etc. ranging from 0.09 ng kg(-1) whole weight for milk to 59.3 ng kg(-1) whole weight for fish, for the sum of the measured PCNs. The most frequently detected congeners were PCNs 66/67, PCN 52, and PCN 73. The highest concentrations were observed in fish, which generally showed congener profiles that reflect some commercial mixtures. The data compares well with other recently reported data for Western Europe. The dioxin-like toxicity (PCN TEQ) associated with these concentrations is lower than that reported for chlorinated dioxins or PCBs in food from Ireland. The dietary exposure of the Irish adult population to PCNs was calculated following a probabilistic approach, using the full dataset of occurrence and current consumption data. The estimates of dietary intakes at approximately 0.14 pg TEQ kg bw(-1) month(-1) for adults on an average diet, reflects the relatively lower occurrence levels.     

PCDD/Fs and dioxin-like PCBs in sediment and biota from the Mondego estuary (Portugal)

The concentrations of 17 polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in sediment and key species as an initial investigation on PCDD/Fs and dl-PCBs contamination in the Mondego estuary (Portugal). The results demonstrated that the values of the total PCDD/Fs (∑PCDD/Fs) concentrations were considerably lower than those of the sum of dl-PCBs (∑dl-PCBs) in all the studied samples. Regarding the contribution of individual congeners, OCDD was the predominant PCDD/F and the mono-ortho PCB 118 and PCB 105 were the dominant PCBs in the majority of the samples. Our results suggest that PCDD/Fs and PCBs behave quite differently along the aquatic food web: ∑PCDD/Fs concentrations were lower in higher trophic-level organisms with fish presenting a distinct PCDD/Fs congeners profile; on the contrary, the higher ∑dl-PCBs values were found in upper-level biota, although not exclusively, and quite similar dl-PCBs congener profiles were observed in nearly all the studied species.     

Dietary exposure to PCBs based on food consumption survey and food basket analysis at Taizhou, China--the world's major site for recycling transformers

The levels of PCBs in different types of food (fish, shellfish, meat, rice, vegetables, and fruits) were analyzed to determine the dietary intake of 37 PCBs for local residents and e-waste workers (all lactating mothers) at Taizhou (China), a major electronic waste scrapping center, in particular for recycling transformers. The exposure to PCBs through dietary intake in Taizhou was estimated at 92.79 ngkg(-1)d(-1), contributed by consumption of freshwater fish (28%), rice (28%), meat (17%), shellfish (9%), vegetables (8%), egg (4%) and marine fish (2%). With regards to WHO-PCB-TEQ values, freshwater fish (40%), shellfish (24%), duck liver (18%) and rice (12%) were the main dietary sources with total daily intake (9.78 pg WHO-PCB-TEQ kg(-1)d(-1)), exceeding the FAO/WHO Tolerable Daily Intake (70 pg TEQkg(-1)body(-1)wt(-1)month(-1)).     

Polychlorinated biphenyls (PCBs) in marine fishes from China: Levels, distribution and risk assessment

Muscle tissues of large yellow croakers (Pseudosciaena crocea) and sliver pomfret (Pampus argenteus) from nine coastal cities of East China including Dalian, Tianjin, Qingdao, Shanghai, Zhoushan, Wenzhou, Fuzhou, Quanzhou and Xiamen were analyzed for polychlorinated biphenyl (PCB) concentrations. Thirty-six PCB congeners were quantified in the fishes, of which 11 congeners were dioxin-like PCBs. The total PCB concentrations of the present study were at the low end of the global range, which may be related to the smaller usage and shorter consumption history of PCBs in China. PCBs 18, 29, 52, 66, 101, 104, 138, 153, 180 and 194 were the major constituents found in the fish samples. Regression analysis showed a strong positive correlation (R² = 0.800; p < 0.001) between total dioxin-like PCBs and total PCB concentrations, and that total PCB concentrations explain 80% of the variability in total dioxin-like PCB concentrations. Among the species investigated, significantly higher concentrations of total PCBs were found in croakers than in pomfrets, which may be attributed to their different feeding and living habits. No significant difference in total PCB concentrations among the cities was observed; principal component analysis (PCA) of PCB profiles indicated that PCB pollution came from similar sources in the sampling areas and that there may be other PCB sources in Dalian and Wenzhou. The calculated carcinogenic risks (CRs) from the two species based on a low consumption group and high consumption group were all greater than 10⁻⁶, suggesting that daily exposure to dioxin-like PCBs via fish consumption results in a lifetime cancer risk of greater than one in one million. In contrast, the hazard quotients (HQs) of noncancer risks were all less than unity.     

Polychlorinated biphenyls in broiler diets: their digestibility and incorporation in body tissues

The influence of dietary amounts of polychlorinated biphenyls (PCBs) was studied on performance, apparent PCB digestibility and PCB accumulation in broiler chickens that were maintained until 42 days of age. Dietary concentrations of supplemented PCBs, based on the sum of seven reference congeners, ranged from 0 to 12 ng/g, which was below the legal maximum of 200 ng PCBs/g fat in Belgian feeds. PCB ingestion did not significantly affect body weight and feed intake. Apparent PCB digestibility was not influenced by dietary levels of added fat varying between 4% and 8%, but was significantly higher in broilers fed diets containing added PCBs. Accumulation of PCBs in the fat fraction of abdominal adipose tissue and breast and thigh muscle greatly depended upon PCB intake. However, PCB contents in the various body fat fractions within the same animal differed, even within muscle tissues, indicating an unequal PCB distribution in body fats.     

The estimation of consumer health risk associated with organochlorine xenobiotics in hard smoked cheese in Poland

The aim of this study was to estimate the health risks associated with consumption of smoked cheeses, which are popular in Poland. The analysis covered polychlorinated biphenyl (PCB) indicator congeners (ndl-PCBs: PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, PCB 180), dioxin-like PCBs (dl-PCBs): non-ortho (PCB 77, PCB 81, PCB 126, PCB 169) and mono-ortho (PCB 105, PCB 114, PCB 118, PCB 156, PCB 157), as well as organochlorine pesticides (OCPs: αHCH, βHCH, γHCH, heptachlor, aldrin, heptachlor epoxid isomer B, dieldrin, pp'DDE op′DDD, pp′DDT, pp′DDD, op′DDT, endrin). The pesticide residues detected in the examined cheese were below the maximum residues levels. The estimated daily intake [lifetime average daily dose (LADD)] referring to the sum of the compounds varied within 4.21·10^?7–3.92·10^?6 mg·kg^?1·day^?1 and was significantly lower than the tolerable daily intake/acceptable daily intake (TDI/ADI) for individual compounds. The health hazard quotient, being the exact measure of the magnitude of exposure potential or a quantifiable potential for developing non-carcinogenic health effects after an averaged exposure period, was also very low, ranging from 2.87·10^?6 to 5.32·10^?5. The obtained results confirmed that the intake of rennet cheese does not pose any consumer health risk in Poland.     

Assessment of reference values for polychlorinated biphenyl concentration in human blood

A chemical factory which produced polychlorinated biphenyls (PCBs) operated in Brescia, North Italy, (about 200000 inhabitants) from the 1930s to the 1980s. High levels of PCBs were recently found in soil, food and people living in an area close to the factory. We performed a survey among the general population living in non-polluted areas of the town in order to define the reference values (RVs) of the non-exposed population. A random sample of subjects aged 20-79 years (50% males) was selected. Participants underwent PCB determination and were interviewed on their residential and occupational history and current diet. For RV determination, subjects who had resided in the polluted area or consumed any food produced in the area in their lifetime were excluded. Eight hundred and ninety-two subjects were contacted, 579 (65%) of whom agreed to participate; 311 of them were considered for RV determination (53% male, mean age=48.7 years). Total PCB serum levels, computed as the sum of the 24 congeners determined, were: mean=5.15ng/ml (SD=8.83), median=4.11ng/ml, range=0.4-34.12ng/ml, 95th centile=14.38ng/ml. Lipid-adjusted mean and median were 897 and 705ng/g lipid, respectively. PCB values showed positive correlations with age (Spearman's r=0.76) and with serum concentration of total cholesterol (r=0.40) and triglycerides (r=0.36). No association was found with gender, cigarette smoking, alcohol or diet. Seven PCB congeners, (PCB 180, 153, 138, 170, 194, 118, and 156), including those at higher chlorination, were present in more than 30% of the subjects and contributed 99% of the total PCB levels, with a modest role of dioxin-like congeners.     

Congener-specific egg contribution of polychlorinated biphenyls to nestlings in two passerine species

Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs.     

Estimation of 1999-2004 dietary daily intake of PCDDs, PCDFs and dioxin-like PCBs by a total diet study in metropolitan Tokyo, Japan

A study of the dietary intake of dioxins, consisting of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) through foods retailed in the metropolitan Tokyo area from 1999 to 2004 was carried out by the total diet-market basket method on the basis of food classification (14 groups) and the data on food consumption in the Tokyo region obtained from the Japan Nutrition Survey. The daily intake of dioxins per kg of body weight for a 50 kg average adult body was 2.18 pg TEQ/kg/day in 1999, 1.87 pg TEQ/kg/day in 2000, 1.25 pg TEQ/kg/day in 2001, 1.60 pg TEQ/kg/day in 2002 and 2003 and 1.55 pg TEQ/kg/day in 2004, respectively. These amounts were less than the tolerable daily intake (TDI) of 4 pg TEQ/kg/day for dioxins established in Japan. The dioxins taken daily through fish and shellfish (group 10) accounted for more than 50% of sum WHO-TEQs. In addition, more than 90% of the daily intake of dioxins was taken through fish and shellfish (group 10), meat and eggs (group 11), milk and dairy products (group 12). Also, this study clearly showed that the ratio of dioxin-like PCBs in the daily intake of dioxins was increasing yearly because the reduction rate of dioxin-like PCBs was lower than that of PCDDs and PCDFs in foods.     

Dietary uptake kinetics of polychlorinated biphenyls from sediment-contaminated sandworms in a marine benthic fish (Pseudopleuronectes yokohamae)

To evaluate the dietary uptake of polychlorinated biphenyls (PCBs) from live food, we investigated the dietary uptake and depuration kinetics of PCBs in a marine benthic fish (marbled sole, Pseudopleuronectes yokohamae) by using as food live sandworms (Perinereis nuntia) that were laboratory-exposed to field-collected PCB-contaminated sediment. Marbled sole were fed the PCB-contaminated sandworms for 28 d and then uncontaminated sandworms for 56 d. The assimilation efficiencies (AEs) of 84 PCB congeners via the gastrointestinal tract (GIT) to the muscle of the fish ranged from 0.21 to 0.78; whole-body AEs would be lower than those of muscle because of the lower PCB concentrations, on a lipid basis. The AEs determined in this study were lower than those in other studies that used PCB-spiked commercial pelletized food. The lower AEs found in this study might be attributable to differences in the food administered (live sandworms vs. commercial pellet food), possibly because of low digestibility of sandworm lipids by marbled sole. In addition, the AEs in this study tended to increase with increasing log octanol-water partition coefficients (K_OW) up to about seven, although AEs in the other studies using commercial pelletized food did not increase with increasing log K_OW. This result suggests the co-transport of highly hydrophobic PCB congeners along with lipids and fatty acids from the digested sandworms into the GIT epithelium cells. The growth-corrected half-lives of 26 PCB congeners in the muscle of fish ranged from 20 to 107 d.     

Polychlorinated biphenyl distribution and faecal excretion in rats fed wheat bran

Polychlorinated biphenyls (PCBs) are abundant and persistent environmental contaminants, which tend to accumulate through the food chain. Because of the toxic potential of these compounds, body burden should be kept as low as possible e.g. by taking dietary measures. In the present report, the effect of wheat bran consumption on absorption of dietary PCBs as well as on excretion of previously absorbed PCBs was investigated in rats. Moreover, the accumulation of 7 reference PCB congeners in liver and abdominal adipose tissue was studied. Faecal excretion of dietary PCBs was significantly higher in rats fed wheat bran compared to its placebo. As a result, apparent PCB digestibility was diminished, but not enough to significantly affect PCB accumulation in liver and abdominal adipose tissue. Furthermore, excretion of previously absorbed PCBs following switching of the rats to a control diet without added PCBs was enhanced by wheat bran fibre intake, although to a much lesser extent than excretion of PCBs originating directly from the diet. Consequently, stimulation of PCB clearance from liver and abdominal adipose tissue due to wheat bran consumption was not detectable. Although no preferential absorption of PCB congeners was observed, PCB patterns in tissues obviously differed from the dietary PCB pattern. This was mainly due to PCBs 52 and 101, which were metabolised in the body. Moreover, reduced levels of PCB 138 were found in liver, while PCB 28 and 138 were predominantly present in adipose tissue. The experiment also demonstrated that PCB redistribution from the liver to the adipose tissue occurs.     

Correlations between dioxin-like and indicators PCBs: Potential consequences for environmental studies involving fish or sediment

Among the numerous PCB congeners, most of the dioxin-like PCBs (DL-PCBs) need to be characterized by hyphenated techniques. It has been shown in several instances that these congeners are well related to the total PCB content in fish. We examined datasets collected mainly in France, on freshwater and marine fish and sediments. A statistical model linking DL- and indicator PCBs was developed for a dataset composed of freshwater fishes, and proved to predict well DL-PCBs from indicator PCBs in all other fish sets, including marine ones. Type II error rates remained low in almost all fish sets. A similar correlation was observed in sediments. Non-dioxin-like PCBs elicit various adverse effects and represent 95% of the total PCBs. A European guideline for them is needed; the correlation between DL- and indicator PCBs could help develop this standard in the future.     

Bioaccumulation of polychlorinated biphenyls in the eel (Anguilla anguilla) at the Camargue Nature Reserve - France

Fish consumption is a potential source of human exposure to pollutants. Here, we study residue levels of PCBs in the eel, Anguilla anguilla, from the Nature Camargue Reserve in southern France. Chromatographic analysis (GC-ECD) found seventy identifiable congeners, among which, 10 are considered as dioxin-like PCBs, such as the non-ortho PCB 81 and the mono-ortho chlorobiphenyls PCB105, 114, 118, 123, 156, 157, 167, 170, 180. Toxic Equivalents (TEQ, WHO 2005 TEF-Toxic Equivalent Factors) varied among sites with a maximum in eels from Mornès (29.6pgg(-1) dry weight). Indicator PCBs (28, 52, 101, 118, 138, 153 and 180) were 22% and 29% of the total PCBs in livers and muscles respectively. Greater homogeneous bioaccumulation in muscle than that in liver suggests an increase risk for humans due to fish consumption.     

Polychlorinated biphenyls (PCBs) and hydroxy-PCBs in adipose tissue of women in Southeast Spain

Polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCBs) were investigated in human adipose tissue samples collected from 20 women undergoing surgery. Mean sum of PCB and sum of OH-PCB levels were 737ng/g of lipid and 8pg/g of lipid, respectively. Among PCBs, congeners 180, 153, 138 and 170 were the most frequent and abundant, and together constituted 72% of the total amount of PCBs in adipose tissue. The PCB congener pattern and the frequencies and concentrations of non-dioxin-like and non-hydroxylated congeners observed in adipose tissue were similar in distribution and order of magnitude to the profile previously published in Spain but lower than that found in other European countries. Among OH-PCB congeners studied, 4-OH-PCB 107/118 was found at the highest concentrations followed by 3'-OH-PCB 180 and 3-OH-PCB 138. To date, no information on levels of PCB metabolites in the Spanish population is available for comparison. These three predominant OH-PCBs contributed 97% of all OH-PCBs. Twelve dioxin-like PCBs contributed around 8% of the total PCB exposure, and all were present in all study subjects. Further research is required to determine trends in human exposure to PCBs and OH-PCBs and how existing banning measures affect exposure.     

Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France)

The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp'-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed. The spider crab was the only species found in the five sampling sites, thus enabling comparison between areas. Specimens from Antifer were much more contaminated (summation operator 16 PCBs in hepatopancreas=2000-4000 ng g(-1) dry weight) than those from other sites (50-1000 ng g(-1) d.w.). Among all the three species, the spider crab appeared more contaminated by PCBs than the edible crab, by a factor 2-3, probably in relation with specific differences in their life cycle. There was no difference due to the gender of the species. Within the different analysed tissues, contamination levels increased from muscle to gonads and hepatopancreas in relation with the fat content. A very similar PCB composition was observed in all samples, PCB fingerprints being characterised by the relative importance of the more persistent PCB congeners: CB153, 138, 180, 187, and 118. Finally, these results were compared to recent food regulations first of maximum marker PCB intake and secondly of maximum dioxin-like PCB intake. By considering the muscle, all samples were far below the regulatory limits; for hepatopancreas and gonads, however, some samples were unfit for human consumption.     

NDL-PCBs in muscle of the European catfish (Silurus glanis): An alert from Italian rivers

The non-dioxin-like polychlorinated biphenyls (NDL-PCBs) highly contribute to the PCB dietary intake of total PCBs. Most of the NDL-PCBs are assumed through ingestion of contaminated fish and fishery products. Therefore, it is important to quantify their presence in aquatic organisms to evaluate human risks associated with fish consumption. The European catfish is a top food-chain predator and is considered a reliable bio-monitoring tool reflecting the state of the environmental organic pollution. From 2006 to 2009, 54 European catfish were captured in four sites covering the area of the Po River (North Italy), and their muscles were analysed to determine the levels of 18 PCBs congeners. All samples presented detectable levels of 18 congeners and, on average, results showed an important presence of NDL-PCBs. The sum of the six congeners (28, 52, 101, 138, 153, 180 IUPAC) was used as indicator of the total PCBs concentration. The 33% of the samples analysed exceeded the maximum levels of 125 ng g⁻¹ set by European regulations in fish. The values measured ranged from 19.7 to 1015.4 ng g⁻¹ (mean 135.6 ± 149.8 ng g⁻¹).