Bioassay-derived dioxin equivalent concentrations in gonads and livers of the Atlantic cod females from the Baltic Sea

Persistent organic pollutants and related biological responses measured in coastal fish using chemical and biological screening methods

The aim of this study was to investigate the spatial distribution, levels of dioxin-like compounds (DLC), and biological responses in two fish species. The viviparous eelpout (Zoarces viviparus) was collected from various locations in the Baltic Sea and in fjords of Kattegat and Skagerrak, while shorthorn sculpin (Myoxocephalus scorpius) was obtained at the polychlorinated biphenyl (PCB) polluted site in North West Greenland. Significant differences were detected both in contaminant levels and relative contributions from either polychlorinated dibenzodioxins (PCDD) or polychlorinated dibenzofurans (PCDF or furans) and mono-ortho- and non-ortho (coplanar) polychlorinated biphenyls (dl-PCB). Fish from the eastern Baltic Sea generally displayed higher contributions from PCDD/F compared to dl-PCB, whereas dl-PCB were generally predominated in fish from Danish, Swedish, and German sites. Levels of dl-PCB in muscle tissues were above OSPAR environmental assessment criteria (EAC) for PCB118, indicating a potential risk of adverse biological effects in the ecosystem, whereas levels of the total WHO-TEQs were below threshold for sea food suggesting limited risks for humans. No significant relationships between levels of DLC (expressed as WHO-TEQ), and biological responses such as the induction of CYP1A enzymatic activity and fry reproductive disorders were observed in eelpout. No marked relationship between WHO-TEQ and combined biological aryl hydrocarbon receptor-mediated transactivity (expressed as AhR-TEQ) was noted. However, there was a positive correlation between polycyclic aromatic hydrocarbon (PAH) metabolites and induction of CYP1A activity, suggesting that PAH exhibited greater potential than DLC to produce biological effects in eelpout from the Baltic Sea.

The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards

A major challenge for society is to manage the risks posed by the many chemicals continuously emitted to the environment. All chemicals in production and use cannot be monitored and science-based strategies for prioritization are essential. In this study we review available data to investigate which substances are included in environmental monitoring programs and published research studies reporting analyses of chemicals in Baltic Sea fish between 2000 and 2012. Our aim is to contribute to the discussion of priority settings in environmental chemical monitoring and research, which is closely linked to chemical management. In total, 105 different substances or substance groups were analyzed in Baltic Sea fish. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were the most studied substances or substance groups. The majority, 87%, of all analyses comprised 20% of the substances or substance groups, whereas 46 substance groups (44%) were analyzed only once. Almost three quarters of all analyses regarded a POP-substance (persistent organic pollutant). These results demonstrate that the majority of analyses on environmental contaminants in Baltic Sea fish concern a small number of already regulated chemicals. Legacy pollutants such as POPs pose a high risk to the Baltic Sea due to their hazardous properties. Yet, there may be a risk that prioritizations for chemical analyses are biased based on the knowns of the past. Such biases may lead to society failing in identifying risks posed by yet unknown hazardous chemicals. Alternative and complementary ways to identify priority chemicals are needed. More transparent communication between risk assessments performed as part of the risk assessment process within REACH and monitoring programs, and information on chemicals contained in consumer articles, would offer ways to identify chemicals for environmental analysis.

Distribution of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofurans in the Jukskei and Klip/Vaal catchment areas in South Africa

Comprehensive two dimensional gas chromatography (GCxGC)-μECD analysis was used to determine 2,3,7,8-substituted dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) distribution in the Jukskei and Klip/Vaal catchment areas from ten sites previously identified as persistent organic pollutant hotspots in major rivers in the Gauteng province of South Africa. Five sediment samples from the Jukskei River catchment area and five sediment samples from the Kilp/Vaal River catchment area were collected for analysis. The extracts were screened for dioxin-like activity using the DR-Luc bioassay prior to GCxGC-μECD analysis. All sediment samples tested positive for dioxin-like activity with total activity ranging from 16 to 37 pg toxic equivalents (TEQ) g(-1) dry weight (dw) for the Jukskei River catchment and 1.5-22 pg TEQ g(-1) dw for the Klip/Vaal River catchment, indicating that the Jukskei River catchment area had higher concentrations of total dioxin-like compounds. Confirmatory tests for the presence of the most potent seven PCDDs and ten PCDFs conducted using GCxGC-μECD revealed presence of 11 PCDD/Fs and 6 PCDD/Fs in the Jukskei and Klip/Vaal River catchments respectively. Total organic carbon (TOC) and particle size distribution analysis were conducted to understand the distribution of PCDD/Fs within the Jukskei and Klip/Vaal catchments.

Coupling passive sampling with in vitro bioassays and chemical analysis to understand combined effects of bioaccumulative chemicals in blood of marine turtles

Conventional target analysis of biological samples such as blood limits our ability to understand mixture effects of chemicals. This study aimed to establish a rapid passive sampling technique using the polymer polydimethylsiloxane (PDMS) for exhaustive extraction of mixtures of neutral organic chemicals accumulated in blood of green turtles, in preparation for screening in in vitro bioassays. We designed a PDMS-blood partitioning system based on the partition coefficients of chemicals between PDMS and major blood components. The sampling kinetics of hydrophobic test chemicals (polychlorinated dibenzo-p-dioxins; PCDDs) from blood into PDMS were reasonably fast reaching steady state in <96 h. The geometric mean of the measured PDMS-blood partition coefficients for PCDDs, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) was 14 L blood kg PDMS(-1) and showed little variability (95% confidence interval from 8.4 to 29) across a wide range of hydrophobicity (logKow 5.7-8.3). The mass transfer of these chemicals from 5 mL blood into 0.94 g PDMS was 62-84%, which is similar to analytical recoveries in conventional solvent extraction methods. The validated method was applied to 15 blood samples from green turtles with known concentrations of PCDD/Fs, dioxin-like PCBs, PBDEs and organochlorine pesticides. The quantified chemicals explained most of the dioxin-like activity (69-98%), but less than 0.4% of the oxidative stress response. The results demonstrate the applicability of PDMS-based passive sampling to extract bioaccumulative chemicals from blood as well as the value of in vitro bioassays for capturing the combined effects of unknown and known chemicals.