Sture Bergek

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in food samples collected in southern Mississippi, USA

In 1994, we analyzed 43 foodstuff samples from local supermarkets in southern Mississippi, USA, for PCDD/PCDF. 2,3,7,8-Cl4DD could be quantified in 31 of these samples. On a lipid basis, levels in meat (0.53-1.10 pg I-TEQ/g) and dairy products (0.42-1.10 pg I-TEQ/g) were slightly lower than those reported from other industrialized countries. While levels in dairy samples from the United States and Europe are comparable, there is a difference in the contribution of individual congeners to the I-TEQ: for example, in milk samples from Germany approximately 40% of the I-TEQ is due to the presence of 2,3, 4,7,8-Cl5DF while in the Mississippi samples this congener only contributes 16%. The highest concentrations of PCDD/PCDF in our study were detected in the farm-raised catfish (10.2-27.8 pg I-TEQ/g). A unique finding was that in addition to the 2,3,7,8-substituted PCDD/PCDF the catfish samples contained many non-2,3,7,8-substituted congeners. This is unusual because vertebrate animals selectively eliminate or metabolize the non-2,3,7,8-substituted congeners.

PCDD and PCDF contamination in catfish feed from Arkansas, USA

One combined catfish feed sample from Arkansas, USA, and its eight ingredients were analyzed for PCDDs and PCDFs. One of the ingredients, soybean meal, was highly contaminated by PCDDs, especially the toxic 2,3,7,8-substituted congeners, e.g., 7.3 pg/g dry weight or 370 pg/g lipid for the 2,3,7,8-tetra CDD. The I-TEQ value for the soybean meal was 11.4 pg/g dry weight or 576 pg/g fat. The corresponding values for the combined catfish feed concentrations were approximately 3 times lower. The congener pattern, the congener profile and the ratio sigma PCDDs/sigma PCDFs for the soybean meal were quite unique. We are not aware of any environmental sample or technical product with similar characteristics. As a result, natural formation of the PCDDs found in the soybean meal cannot be ruled out.

Dioxins in cod and herring from the seas around Sweden

Abstract The levels of PCDDs and PCDFs in pooled samples of cod, herring and whitefish from different fishing grounds in the seas around Sweden were determined by HRGC-HRMS. The results are expressed as TCDD equivalents, calculated according to the recently described Nordic model. The levels in pooled cod fillets were below or close to the limit of quantitation (ca 0.2 pg TCDD equivalents/g wet weight), whereas the levels in herring were 1.8–9.0 pg/g, the highest levels being found in Baltic herring. The levels in the two pooled samples of whitefish studied varied widely (2.3 and 19 pg/g).

Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzo-furans (PCDF) in seal blubber

Abstract Blubber samples from seals collected in waters around the Scandinavian peninsula and from the Antarctic have been analyzed for the presence of PCDD and PCDF. The results do not indicate any substantial species or spatial differences in levels for animals representing the northern hemisphere but lower levels were found in the samples collected in the Antarctic. Among marine mammals highly persistent organochlorines normally increase with increasing age. In our study no clear age or sex dependence in levels of PCDD and PCDF was found. The levels of PCDD and PCDF in seal blubber are of the same magnitude as the levels found in humans.

Biotransfer and bioaccumulation of PCDD/PCDFs from soil: Controlled exposure studies of chickens

Abstract Controlled exposure studies under laboratory and field conditions have been initiated to investigate the biotransfer and bioaccumulation of PCDD/Fs in soil, at low concentrations, to animals which have contact with soil. The chicken was chosen as a model for grazing animals. The accumulation over time of specific isomers is being tracked in eggs, blood, feces, liver, adipose, and edible flesh. Measurable increases of PCDD/F concentration in eggs of exposed chickens, as compared to controls, were seen after 30 days of exposure. The exposure characterization, as well as data on isomer specific biotransfer and bioaccumulation rates in eggs are discussed.

PCDD, PCDF, and PCB in Farm-Raised Catfish from Southeast United States - Concentrations, Sources, and CYP1A Induction

Nine catfish fillets, three catfish nuggets, two feed samples, and one pond sediment were analyzed for PCDD, PCDF, and PCB. Farm-raised catfish from Mississippi, Alabama, and Arkansas contained significant levels of 2,3,7,8-substituted PCDD and PCDF. In addition, a large number of non-2,3,7,8-substituted congeners were present in all samples. The catfish fillets and catfish nuggets also contained high concentrations of dioxin-like PCB, as well as a number of non-dioxin-like PCB. The TEQ based on PCDD and PCDF ranged from 9.5 to 43.0 pg/g lipid and the TEQ based on PCB ranged from 0.45 to 4.9 pg/g lipid for all catfish samples. The dioxin-like PCB contributed 4-16% to the total TEQ (PCDD/PCDF/PCB) for the catfish samples. The major source for the PCDD, PCDF, and PCB appears to be from feed and not from pond sediment. Immunoreactive CYP1A protein was elevated 2.5 fold in the pond-raised catfish compared to the aquarium-raised one. The results of this study suggest that the PCDD/PCDF are more important than the PCB in the CYP1A induction.

Biotransformation enzyme activities and PCDD/PCDF levels in pike caught in a Swedish Lake

Abstract Recently, analysis of organochlorines in sediment and in pike from Lake Vanern, Sweden, showed a north-south gradient of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In the present study, good correlations were found between muscle 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents and liver ethoxyresorufin-O-deethylase (EROD) activities (and P4501A levels) in pike caught at three sampling sites along the north-south gradient in the lake. This comparison between tissue levels of PCDD/PCDF and EROD activity (and P4501A) may indicate that TCDD or structural analogs could be responsible for the observed induction of the pike P450 system. It must, however, be taken into account that the analysed contaminants often do not appear alone but are, rather, accompanied by a range of other substances which may be inducers or antagonists.

Results from the first year of the Swedish dioxin survey

Abstract PCDD/F levels are presented for food baskets, raw and fried herring, wolf muscle and moose tallow collected from the same area, three burbot liver samples, a sediment core from the Baltic Sea and leach water from three garbage dumps. Levels in food baskets were at or below detection limits making the estimation of intake via the diet difficult. Frying herring produces no net change in PCDD/F levels. Moose have lower PCDD/F levels than wolf from the same area. Levels in burbot liver samples are much higher near industrial discharges than in a more undisturbed area. The top 4 cm of the sediment core contain the highest levels of PCDD/F. Thereafter the levels drop and reach a low level. This low level is probably caused by contamination during sampling and is not evidence of PCDD/F presence far back in time. Leach water from city dumps contains low levels of PCDD/F but that from a dump that takes industrial wastes had higher levels and a different congener pattern.

Levels and possible sources of PCDD/PCDF in sediment and pike samples from Swedish lakes and rivers. (Part one)

Abstract One goal of the Swedish survey project is to discover possible sources of PCDD/F. Bottom sediment and pike were sampled at various sites near different types of industries along the coast line of two lakes and one river. The results show background levels of PCDD/F in some lakes which can only be explained by atmospheric input. In some lakes paper mill emissions of chlorinated PCDD/F give high levels of local contamination (≈1 ng/g IG) within short distances (

Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran levels and patterns in fish and fish-eating wildlife in the Baltic Sea

Abstract PCDD/F patterns in different fish species collected at the same site are different from each other indicating species differences in bioaccumulation. There are higher levels of specific congeners in older/larger herring caught at the same site. There are geographical differences in PCDD/F levels and patterns in herring, pike and burbot which may be linked to specific point sources of PCDD/F. PCDD/F levels are much higher in fish-eating birds than in their major fish prey indicating biomagnification. PCDD/F levels in seals, however, do not indicate biomagnification. Levels of PCDD/F in homogenates of guillemot eggs collected at five-year intervals (1974, 1979, 1984, 1989) indicate a possible reduction in environmental PCDD/F levels during the 1980s.