Karin Wiberg

Science and policy on endocrine disrupters must not be mixed: a reply to a “common sense” intervention by toxicology journal editors

The “common sense” intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail. We call for a better founded scientific debate which may help to overcome a polarisation of views detrimental to reaching a consensus about scientific foundations for endocrine disrupter regulation in the EU.

Overview on environmental fate of chlorinated dioxins and dibenzofurans. Sources, levels and isomeric pattern in various matrices

Abstract Polychlorinated dioxins and dibenzofurans have been identified in technical products and pesticides, most of which are not very widely used today. Other sources are incinerators of various types like MSW incinerators, but also hazardous waste incinerators and industrial incinerators. PCDDs and PCDFs have also been identified in exhausts from cars running on leaded gasoline with halogenated additives. Background levels of PCDDs and PCDFs have been identified in fish and other aquatic organisms from the Great Lakes and the Baltic Sea, and also in human adipose tissue samples from USA, Canada, Sweden, Japan and Viet Nam as well as in samples of breast milk from Sweden, Denmark, West Germany, the Netherlands, Yugoslavia and Viet Nam. The isomeric pattern in all these biological samples is very similar.

Absorption of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans by breast-fed infants

The absorption of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans was studied in four breast-fed infants. The absorption was measured by comparing the estimated total intake and the excretion in faeces, during 48 hours, at three different time points; 1, 2 and 3 months post parta. The levels of the analysed compounds in the human milk are typical for Sweden, i.e approximately 20 ppt toxic equivalents for the dibenzo-p-dioxins and dibenzofurans and for the polychlorinated biphenyls approximately 16 ppt toxic equivalents. For most of the congeners the absorption is found to be over 95%. Higher excretion is noticed for heptachlorinated and octachlorinated dioxins.

Physical-Chemical Property Data for Dibenzo-p-dioxin (DD), Dibenzofuran (DF), and Chlorinated DD/Fs: A Critical Review and Recommended Values

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are of global concern due to their persistence, their tendency to bioaccumulate, and their extremely high toxicit ...

Bioturbation-Driven Release of Buried PCBs and PBDEs from Different Depths in Contaminated Sediments

Bioturbation can remobilize previously buried contaminants, leading to an increased exposure of aquatic biota. The remobilization of buried polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) from three different sediment depth layers (2.0-2.5 cm, 5.0-5.5 cm, and 10.0-10.5 cm) was studied in a laboratory experiment with two benthic macrofauna species, the amphipod Monoporeia affinis and the polychaete Marenzelleria spp. Remobilization of PCBs and PBDEs was significantly higher in the presence of Marenzelleria spp. than in M. affinis treatments and controls (without macrofauna). The highest remobilization occurred from the most shallow layers (2.0-2.5 cm > 5.0-5.5 cm > 10.0-10.5 cm), but contaminants were remobilized due to bioturbation from layers down to at least 10 cm. Congeners with lower hydrophobicity were remobilized to a higher extent than more hydrophobic congeners. The contaminant distribution between the particulate and the dissolved phase in the water column depended on hydrophobicity and burial depth of the contaminant, with congeners from deeper layers displaying an increased distribution to the particulate phase. Release fluxes and sediment-to-water mass transfer coefficients (MTCs) show that bioturbation by the polychaete Marenzelleria spp. can lead to a significant remobilization of buried contaminants from Baltic Sea sediments.

A model assessment of polychlorinated dibenzo-p-dioxin and dibenzofuran sources and fate in the Baltic Sea.

The contamination of the Baltic Sea with polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) has resulted in restrictions on the marketing and consumption of Baltic Sea fish, making this a priority environmental issue in the European Union. To date there is no consensus on the relative importance of different sources of PCDD/Fs to the Baltic Sea, and hence no consensus on how to address this issue. In this work we synthesized the available information to create a PCDD/F budget for the Baltic Sea, focusing on the two largest basins, the Bothnian Sea and the Baltic Proper. The non-steady state multimedia fate and transport model POPCYCLING-Baltic was employed, using recent data for PCDD/F concentrations in air and sediment as boundary conditions. The PCDD/F concentrations in water predicted by the model were in good agreement with recent measurements. The budget demonstrated that atmospheric deposition was the dominant source of PCDD/Fs to the basins as a whole. This conclusion was supported by a statistical comparison of the PCDD/F congener patterns in surface sediments from accumulation bottoms with the patterns in ambient air, bulk atmospheric deposition, and a range of potential industrial sources. Prospective model simulations indicated that the PCDD/F concentrations in the water column will continue to decrease in the coming years due to the slow response of the Baltic Sea system to falling PCDD/F inputs in the last decades, but that the decrease would be more pronounced if ambient air concentrations were to drop further in the future, for instance as a result of reduced emissions. The study illustrates the usefulness of using monitoring data and multimedia models in an integrated fashion to address complex organic contaminant issues.

Congener fingerprints of tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans in Baltic surface sediments and their relations to potential sources

Comprehensive congener fingerprints of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), including non-2,3,7,8-substituted congeners, in 142 surface sediment samples from the Baltic Sea were characterized by Principal Component Analysis (PCA). The pattern analysis revealed source specific indicators of chlorophenol use, high temperature processes, chlorine bleach/chloralkali production and a source signature suggested to originate from pulp/paper or related production. Congener patterns in sediments from offshore and pristine coastal areas showed strong resemblance to patterns of atmospheric deposition and flue gases, indicating that these sources have high impact in areas that are not affected by point sources. Prominent contributors to the patterns of hotspot areas along the Swedish coast included chlorophenol indicators and a source characterized by hexa-CDDs while the contribution of the traditional chlorine bleach pattern was weaker. This study demonstrates the importance of comprehensive PCDD/F congener analysis for identifying links to candidate sources.

Chiral pesticides as tracers of air–surface exchange

The enantiomers of chiral pesticides are selectively broken down in soil and water to yield residues and metabolites, which are non-racemic. The distinctive enantiomer signatures of residues are pr ...

PCDD/F Source Apportionment in the Baltic Sea Using Positive Matrix Factorization

Positive Matrix Factorization (PMF) was used to identify and apportion candidate sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) in samples of offshore and coastal surface sediments from the Baltic Sea. Atmospheric deposition was the dominant source in offshore and pristine areas, in agreement with previous studies. Earlier chlorophenol use and a source suggested origins from pulp and paper production and related industries were identified as important coastal sources. A previously presumed major source, chlorine bleaching of pulp, was of only minor importance for modern Baltic surface sediments. The coastal source impacts were mostly local or regional, but pattern variations in offshore samples indicate that coastal sources may have some importance for offshore areas. Differences between sub-basins also indicated that local and regional air emissions from incineration or other high-temperature processes are more important in the southern Baltic Sea compared to those in northerly areas. These regional differences demonstrated the importance of including offshore sediments from the Bothnian Bay, Gulf of Finland, and other areas of the Baltic Sea in future studies to better identify the major PCDD/F sources to the Baltic Sea.

Enantioselective Analysis of Organochlorine Pesticides in Herring and Seal from the Swedish Marine Environment

Abstract Factors influencing the changes of enantiomeric ratios (ERs) in herring ( Clupea harengus ), grey seal ( Halichoerus grypus ), harbour seal ( Phoca vitulina ) and ringed seal ( Phoca hispida ) collected along the Swedish coastline were studied by enantioselective high-resolution gas chromatography (HRGC). Three-year-old male and female herring individuals from different sampling sites were selected, whereas seal blubber and liver samples represented different species, sexes and geographical locations. Enantioselective analysis of α-hexachlorocyclohexane (α-HCH), chlordanes and chlordane metabolites were performed. In general, herring showed similar ERs within the Baltic Sea. Results indicate that species specific differences are important factors controlling the ERs of Baltic seals. Inverse ERs in seal blubber and liver, and a low deviation from the racemic ratio of some components in the liver, indicate that not only enantioselective degradation but also stereoselectivity of other processes are responsible for the changes of ERs in biota.