Polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls in fish from the Netherlands: concentrations, profiles and comparison with DR CALUX® bioassay results

Data analysis strategies for the characterization of chemical contaminant mixtures. Fish as a case study

Thousands of chemicals are potentially contaminating the environment and food resources, covering a wide spectrum of molecular structures, physico-chemical properties, sources, environmental behavior and toxic profiles. Beyond the description of the individual chemicals, characterizing contaminant mixtures in related matrices has become a major challenge in ecological and human health risk assessments. Continuous analytical developments, in the fields of targeted (TA) and non-targeted analysis (NTA), have resulted in ever larger sets of data on associated chemical profiles. More than ever, the implementation of advanced data analysis strategies is essential to elucidate profiles and extract new knowledge from these large data sets. Specifically focusing on the data analysis step, this review summarizes the recent progress in integrating data analysis tools into TA and NTA workflows to address the challenging characterization of chemical mixtures in environmental and food matrices. As fish matrices are relevant in both aquatic pollution and consumer exposure perspectives, fish was chosen as the main theme to illustrate this review, although the present document is equally relevant to other food and environmental matrices. The key features of TA and NTA data sets were reviewed to illustrate the challenges associated with their analysis. Advanced filtering strategies to mine NTA data sets are presented, with a particular focus on chemical filters and discriminant analysis. Further, the applications of supervised and unsupervised multivariate analysis methods to characterize exposure to chemical mixtures, and their associated challenges, is discussed.

Polychlorinated dioxins, furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food from Italy: Estimates of dietaryintake and assessment

Abstract

Dietary intake of polychlorinated dioxins and furans (PCDD/Fs) and dioxin‐like polychlorinated biphenyls (dl‐PCBs) from various foods (fish and seafood, meat and meat‐based products, milk and dairy products, hen eggs, olive oil and fats) was investigated for various sex/age groups of the Italian population. The concentrations of PCDD/Fs and dl‐PCBs and their contribution to total TEQ values varied depending on food matrix. Fish (0.50 pg WHO‐TEQ/g wet weight) and seafood (0.16 pg WHO‐TEQ/g wet weight) showed the highest mean concentrations of PCDD/Fs plus dl‐PCBs, followed by meat (1.70 pg WHO‐TEQ/g lipid weight), meat based products (1.03 pg WHO‐TEQ/g lipid weight), milk and dairy products (0.78 pg WHO‐TEQ/g lipid weight), hen eggs (0.71 pg WHO‐TEQ/g lipid weight), fats (0.27 pg WHO‐TEQ/g lipid weight) and olive oil (0.09 pg WHO‐TEQ/g lipid weight). In all samples WHO‐TEQ PCDD/F plus dl‐PCB concentrations fulfilled the European Union food law, except in pork loin samples (1.39 pg WHO‐TEQ/g lipid weight). Differences in exposure depending on the sex/age groups (children > teenagers > adults > elders) and hypotheses considered (lower bound and upper bound) were encountered. Non‐cancer risk values showed a low exposure. Carcinogenicity risk results revealed that highly exposed individuals were distributed over all sex/age groups, even though the proportion of individuals exceeding the safe limit was higher in children. These data once again underline the importance of trying to control the levels of these contaminants in fishery products, particularly in fish, who represents one of the main exposure sources for consumers.

Practical Application

This paper may help the consumer in making food choices to minimize the exposure risk to dioxins, furans and PCBs

Induction of AhR transactivation by PBDD/Fs and PCDD/Fs using a novel human-relevant, high-throughput DRhuman CALUX reporter gene assay

Polychlorinated dioxins and dibenzofurans (PCDD/Fs) are highly toxic contaminants that are strictly regulated and monitored in the environment and food to reduce human exposure. Recently, the increasing occurrence of polybrominated dioxins and dibenzofurans (PBDD/Fs) in the environment is raising concerns about the impact on human health by the combined exposure to chlorinated and brominated analogues of dioxins. Toxicological properties of PBDD/Fs relative to PCDD/Fs have not been firmly established, and brominated dioxins are not included in routine monitoring programs. In this study, we set out to determine human-relevant congener-specific potency values for a range of brominated and chlorinated dioxin congeners, based on their aryl hydrocarbon receptor (AhR)-mediated mode of toxic action. Transactivation of the AhR was measured using dioxin-responsive (DR) CALUX reporter gene assays. Because of known species-differences in dioxin-mediated toxicity, we developed and used a HepG2 human liver cell-based DR human CALUX assay that is a variant of the rodent-based DR CALUX. The assay was found to be highly inducible and stable, with low variations between independent measurements. Using both DR CALUX assays in an automated high-throughput mode we found that overall PBDD/Fs were as potent as PCDD/Fs in inducing AhR transactivation, but congener-specific differences were observed. We also observed species-specific differences in sensitivity and potency when comparing DR human REP values to those obtained in the rat-based DR CALUX. Finally, we observed significant differences between WHO-TEF values and DR human REP values, suggesting that actual WHO-TEF values may underestimate the hazards associated with exposure of humans to dioxins.

Dioxin and PCB residues in meats from Italy: Consumer dietary exposure

In order to investigate PCB and PCDD/F concentrations and potential human health risk a study has been conducted in meat samples (beef, pork, chicken and turkey) purchased from Italian supermarkets. PCBs were dominant (41.8-77.7 ng g^-1 l.w.) with respect to PCDD/Fs (20.1-91.1 pg g^-1 l.w.). The levels were variable and largely dependent upon the type of meat. Accumulation pattern showed a distribution typically reported for meat. PCBs tended to decrease from lowest to highest congeners, while for PCDD/Fs the concentration profile was dominated by highly chlorinated dioxins and furans. Concentrations of PCDD/Fs plus dl-PCBs and indicator PCBs exceeding the EU maximum permissible levels were found in 23.3% and 53.3% of the samples, respectively. Exposure estimates to PCDD/Fs plus dl-PCBs (0.08-4.16 pg WHO-TEQs kg^-1 b.w. w.^-1) were within the new limit proposed by the EFSA's expert panel, except for pork sausage, showing a twofold higher value. Concerning the exposure derived from indicator PCBs, the maximum level set by different European countries (10 ng kg^-1 b.w. d.^-1) was surpassed solely via consumption of pork sausage (17.22 ng kg^-1 b.w. d.^-1), thought also the estimated intake from hamburger consumption (6.88 ng kg^-1 b.w. d.^-1) merits attention being close to guideline limit.

PCBs and PCDD/Fs in Bluefin Tuna: Occurrence and Dietary Intake

Polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-furans (PCDD/Fs) were measured in Mediterranean bluefin tuna (Thunnus thynnus) to verify the compliance with the EU regulations for food commercialization. The estimated intakes were also evaluated. The analyses were performed by gas chromatography-ion trap tandem mass spectrometry (GC-MS-MS). The PCBs were dominant (1132.0 ng g^−1 l.w.), followed by PCDFs (23.2 pg g^−1 l.w.) and PCDDs (8.5 pg g^−1 l.w.). The pollutant levels (dl-PCBs: 0.7 pg TEQ/g w.w.; PCDD/Fs: 1.9 pg TEQ/g w.w.) and their sum expressed as TEQ values (2.6 pg TEQ/g w.w.) remained below the limits for human consumption proposed by the European Union. On the contrary, the sum of the six indicator non-dioxin-like PCBs (84.2 ng g^−1 w.w.) was slightly above the maximum level fixed by the in-force legislation. The estimated dietary intakes for PCDD/Fs plus dl-PCBs were below the toxicological reference values (TRVs) set by various international bodies, while non-cancer and cancer risk assessment revealed a safety concern. Additionally, the estimated intake of ndl-PCBs exceeded the maximum levels set by different European countries. These findings suggest caution in tuna consumption together with an active and frequent surveillance of the chemical quality of its flesh.

Accumulation of persistent organic pollutants in consumers of eel from polluted rivers compared to marketable eel

Globally, many river sediments are seriously contaminated with persistent organic pollutants (POPs) known to accumulate in aquatic food. In the Netherlands, toxicological risks of human exposure to dioxins and dioxin-like compounds led to a ban on eel fishing in the Rhine-Meuse delta. The aim of this study is to investigate differences in serum POP levels in consumers of eel from high-polluted areas and consumers of eel from low-polluted areas or aquaculture. In total 80 Dutch men were included, aged 40-70 years, with a habitual eel consumption of at least one portion (150 g) per month. Total levels of dioxins and dioxin-like compounds were measured in serum of all participants with the DR CALUX bioassay, validated with GC-MS. For a subgroup of 38 participants extensive POP measurements were performed. We revealed that consumption of eel from polluted rivers resulted in 2.5 and up to 10 times increased levels of dioxins and polychlorinated biphenyls (PCBs) respectively compared to controls. The highest PCB levels were detected for PCB 153, with a median level of 896 ng/g lipid and a maximum level of 5000 ng/g lipid in the high-exposed group. Furthermore, hydroxylated PCB metabolites (OH-PCBs: sum of 4-OH-CB107, 4-OH-CB146, 4'-OH-CB172, and 4-OH-CB187) were 8 times higher in men who consumed eel from polluted areas, and detected at levels (median 4.5 ng/g ww) reported to cause adverse health effects. Also, the majority of the perfluoroalkyl substances (PFASs) were significantly higher in consumers of eel from pullulated areas. In conclusion, this study is the first to reveal that (past) consumption of eel from polluted rivers resulted in high body burdens of dioxins, PCBs, OH-PCBs and PFASs. We confirmed the predictions made in a former risk assessment, and the high levels of dioxins and dioxin-like compounds as well as the OH-PCBs are of health concern.

Dioxin-like biological activity of organic extracts from sediments and fish livers sampled along the Israeli Mediterranean and Red Sea coasts

This study provides, for the first time, a baseline evaluation of dioxin-like biological activity in sediments and fish sampled in- and adjacent to anchorages along the Mediterranean and Red Sea coasts of Israel. It indicates the effect of past pollution, still present in the sediments of older Israeli harbors, with putative contribution of still existing sources of pollution. A commercial reporter gene bioassay was used to evaluate the biological activity of dioxin-like compounds extracted from the samples. HRGC/HRMS analysis of several samples contributed a profile of dioxin-like compounds in sediments and fish. The results point out 1,2,3,4,6,7,8-HeptaCDD, 2,3,4,6,7,8-HexaCDF, 1,2,3,4,6,7,8-HeptaCDF, РСВ-126 and РСВ-118 as major contributors to the dioxin-like activity in sediments. It indicates polychlorinated biphenyls non-selective absorption in fish livers, in contrary to a biased accumulation of poorly chlorinated and more potent dibenzodioxins and dibenzofurans.

A survey of dioxin-like contaminants in fish from recreational fishing

The dioxin and dioxin-like compounds are regarded as one of the most toxic group of environmental contaminants. Food for the commercial market is regularly monitored for their dioxin levels and the concentration allowed in food is strictly regulated. Less is known about locally caught fish from recreational fishing, which is often brought home for consumption. This can be fish caught from nearby lakes or streams or fish with marine origin close to industrial areas or harbours that are not regularly monitored for their dioxin levels. In this study, we established collaboration with schools in 13 countries. We received 203 samples of 29 different fish species of which Atlantic cod was the most abundant followed by brown trout and pollock. In general, the majority of samples from the participating countries had low concentrations (between 0.1 and 0.2 pg/g chemical-activated luciferase gene expression toxic equivalency wet weight (CALUX TEQ w.w.)) of dioxins and dioxin-like PCBs. Only 18 samples had concentrations above 1 pg/g CALUX TEQ w.w., and only 2 dab samples had concentration above maximum levels set by the European Commission. The Atlantic cod samples showed a significant reduction in the concentrations of dioxins with increasing latitude indicating less contamination of dioxin and dioxin-like compounds in the north of Norway. The results indicate that a moderate consumption of self-caught fish at presumed non-contaminated sites does not represent a major risk for exposure to dioxins or dioxin-like compounds at concentrations associated with adverse health effects. Recreational fishermen should, however, obtain knowledge about local fish consumption advice.

Dioxins, PCBs and heavy metals in Chinese mitten crabs from Dutch rivers and lakes

Chinese mitten crab is an invasive species in many European rivers and lakes. Data from the UK indicated high levels of dioxins and PCBs, in particular in the brown meat in the body. This was confirmed by studies in the Netherlands, showing average levels of dioxins and PCBs in the meat in the body of 43 pg TEQ g(-1) ww in crabs caught in the large rivers. Levels in crab of lakes in the Northern part of the Netherlands were on average 3.7-fold lower. Consumption of crabs from polluted areas results in a relatively high dose of dioxins and dl-PCBs and could significantly increase the intake above the TWI. However, in general consumption of these crabs is low, even in the Asian sub-population in the Netherlands. Cadmium and lead levels were higher in crabs from contaminated areas, but for mercury and arsenic there was no clear difference. Consumption of crabs would not result in significant risks for cadmium and mercury. For lead the daily intake could be raised above the BMDL01 for neurodevelopmental toxicity, but this would only occur on a limited number of days. For arsenic the exposure would exceed the lower end of the BMDL01 values for certain cancers, but again, the infrequent consumption by most consumers reduces this risk. Furthermore, speciation showed that most arsenic in crabs was probably not a toxic inorganic form, but likely to be in an organic form.

Characterization of organochlorine pesticides, brominated flame retardants and dioxin-like compounds in shellfish and eel from Fiji

This article gives an overview of a range of persistent organic pollutant chemical levels in shellfish (Batissa violacea and Anadara antiquata) species and eel (Gymnothorax flavimarginatus) from Fiji. As there is limited data in published literature to date, this paper reports first data on a range of persistent organic pollutants and highlights the more prominent POP chemicals present in marine biota in Fiji. A significant number of POP chemicals were detected (e.g. 17 PCDD/PCDF, 12dl-PCBs, organochlorine pesticides and brominated flame retardants), the concentrations found were generally low (e.g. parts per billion level). The low levels of contamination are indicative of a low input from long range and short-range transport as well as few local point sources. Also concentrations of POPs in eel and shellfish from Fiji are low in comparison to wild species in other regions and are within acceptable limits for POP chemicals in fish and fishery products set by the European Union. It describes also results of early studies on basic POPs levels in shellfish in several Pacific Island Countries, which generally show relatively low levels.

Screening for PCDD/Fs and dl-PCBs in local and imported food and feed products available across the State of Kuwait and assessment of dietary intake

A total of 318 local and imported meat, milk, eggs, fish, and animal feed samples collected in Kuwait were analyzed by cell-based reporter gene assay (Dioxin-Responsive Chemical Activated LUciferase gene eXpression DR-CALUX) for PCDD/Fs and dl-PCBs. The bioanalytical equivalents (BEQs) obtained by DR-CALUX bioassay were compared with the official maximum limits according to the European Commission (EC) regulations. Suspected and randomly chosen negative samples were analyzed by gas chromatography-high resolution mass spectrometry (GC-HRMS). The results showed that among suspected samples, one sample was confirmed to be non-compliant. The positive sample was of imported origin. The correlation coefficient of 0.98 between DR-CALUX and GC-HRMS was found. Moreover, the average daily intakes of PCDD/Fs and dl-PCBs for the Kuwaiti population were estimated. Results obtained in this study were discussed and compared with other published data.

Metabolic activation of nonpolar sediment extracts results in enhanced thyroid hormone disrupting potency

Traditional sediment risk assessment predominantly considers the hazard derived from legacy contaminants that are present in nonpolar sediment extracts, such as polychlorinated biphenyls (PCBs), dioxins, furans (PCDD/Fs), and polyaromatic hydrocarbons (PAHs). Although in vivo experiments with these compounds have shown to be thyroid hormone disrupting (THD), in vitro their THD potency is not observed in nonpolar sediment extracts. This is hypothesized to be due to the absence of in vitro biotransformation which will result in bioactivation of the lipophilic compounds into THD hydroxyl metabolites. This study reveals that indeed metabolically activated nonpolar contaminants in sediments can competitively bind to thyroid hormone transport proteins. Sediment fractions were incubated with S9 rat microsomes, and the metabolites were extracted with a newly developed method that excludes most of the lipids to avoid interference in the applied nonradioactive 96-well plate TTR competitive binding assay. Metabolic activation increased the TTR binding potency of nonpolar fractions of POP-polluted sediments up to 100 times, resulting in potencies up to 240 nmol T4 equivalents/g sediment equivalent (nmol T4-Eq/g SEQ). This demonstrates that a more realistic in vitro sediment THD risk characterization should also include testing of both polar and medium polar sediment extracts for THD, as well as bioactivated nonpolar sediment fractions to prevent underestimation of its toxic potency.

Spatial trends of dioxin-like compounds in Atlantic anguillid eels

Several temperate freshwater eel stocks have experienced unsustainable declines, yet to be explained. The decline of lake trout (Salvelinus namaycush) in Lake Ontario has been linked to aryl-hydrocarbon receptor agonists such as polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs), and the question remains whether eels are affected similarly by these compounds. Concentrations of PCDD/Fs, dl-PCBs, and PCNs were determined in eels collected at seven locations in eastern Canada including L. Ontario, one location in New York, USA, and one location in Flanders, Belgium. Concentrations varied greatly among origins, indicating dissimilar historic loadings to local areas. The risk to eel reproduction was evaluated with 2,3,7,8-TCDD toxic equivalents, and increased by 10-fold from the least to most contaminated site. The risk to eel recruitment from dioxin-like compounds in American eel using available guidelines is low. The development of a more comprehensive model for eel recruitment risk assessment due to dioxin-like compounds, using eel-specific guidelines, is recommended. Toxic equivalents were 5-fold higher when based on mammalian toxic equivalency factors compared to fish values. About half of the eels captured in L. Ontario exceeded the Canadian guideline for fish consumption (20pg TEQ g(-1) ww), but there were no other exceedances in Canada. The current risk to eel consumers in Canada is low overall, except for highly urbanized and industrialized areas.

Use of a highly sensitive recombinant hepatoma cell method to determine dioxin concentrations in samples of fish and crab from a hotspot area

A new and easy fast-screening test (the Ad-DR (adenoviral vector-dioxin response) bioassay) for dioxins in biological samples from highly dioxin-contaminated areas was developed. The aryl-hydrocarbon-receptor (AhR) reporter system was utilized to transport a dioxin-responsive-element (DRE) via an adenovirus vector into rat hepatoma (H4IIE) cells before each experiment; these DRE-H4IIE cells were utilized in the Ad-DR bioassay. Biological extracts were simultaneously analyzed by the Ad-DR bioassay and high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). A good correlation was found between the results of the HRGC/HRMS assay and those of the Ad-DR bioassay (R(2) = 0.920, p < 0.001). The bio-analytical equivalent (BEQ) value found in fish or crab caught in the abandoned pentachlorophenol plant (AP) was extremely high compared with the BEQ in fish or crab caught in two rivers nearby this abandoned plant. Dioxins were more heavily bioaccumulated in fish viscera than in fish muscles or in the whole fish. Two-way analysis of variance tests identified the significant effects of fish collection site, fish or crab tissue sample and the interaction between them on dioxin levels in the tissues of these aquatic animals. In conclusion, the Ad-DR bioassay is a useful tool to determine dioxin levels in samples of fish and crab. Compared with fish tissues, where a sample is taken (in the PCP plant or nearby rivers) is the most important factor to determine bioaccumulation of dioxins in fish.

The need and potential of biosensors to detect dioxins and dioxin-like polychlorinated biphenyls along the milk, eggs and meat food chain

Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS) and the chemical activated luciferase gene expression method (CALUX bioassay)), each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain.

Non-dioxin-like PCBs in ten different fish species from the Danube river in Serbia

This work has been developed to examine the level of non-dioxin-like (ndl) PCBs (28, 52, 101, 138, 153 and 180) in (a) ten different freshwater fish species from the Danube river, (b) two sampling points: up and downstream of the industrial zone of the city of Pancevo (ecological hot spot in Serbia) and (c) two time points i.e., in 2001 and 2006. Obtained results would serve to analyse spatial, temporal and congener profile characteristics of ndl PCBs cumulated in fish tissues due to environmental pollution. Sixty-four samples of the following species were collected: wels (Silirus glanus), pike (Esox lucius), bream (Abramis brama), crucian carp (Carassius carassius), pike pearch (Stizostedion lucioperca), barbel (Barbus barbus), tench (Tinca tinca), sterlet (Acipenser ruthenus L.), common carp (Cyprinus carpio) and bighead carp (Hypophthalmichthys nobilis). Gas chromatography coupled with electron capture detector was used for analysis of ndl PCBs. Total ndl PCBs content in upstream samples ranged from 2.7 to 98.1 ng/g and from 4.9 to 68.3 ng/g in 2001 and 2006, respectively. During the 5 years, ndl PCBs content increased significantly in downstream samples i.e., ndl PCBs varied from 13.7 to 46.1 ng/g and from 14.4 to 107.2 ng/g in 2001 and 2006, respectively. PCBs 138 and 180 were predominant congeners in 2001, while in 2006 the most abundant PCB congeners were 138 and 153. In 2006, the presence of PCB 28 and PCB 52 has indicated a recent contamination event. Data on continual monitoring of PCBs in all relevant environmental compartments together with appropriate biomonitoring data are expected to give comprehensive insight into the fate and behaviour profile of these contaminants.

Concentration of DL-PCBs in fish from market of Parma city (north Italy): estimated human intake

The concentrations of 12 congeners of non-ortho and mono-ortho dioxin-like polychlorinated biphenyls (ΣDL-PCB) were measured in 30 fish samples from Parma markets by GC/MS technique. The samples were randomly purchased, choosing the species commonly found in supermarkets. The concentration of DL-PCBs estimated remained under the fixed Italian limit of 4 pg g(-1)ww WHO-TEQ (World Health Organization-Toxic Equivalent) in the major part of the samples, so the situation seems to be not at a level sufficient to pose a risk to human health of the Parma population. The medium daily intake for DL-PCBs for Italian consumers (Parma) was also estimated. This value generally resulted minor than 2 pg g(-1) ww WHO-TEQ kg(-1) body weight, exceeding only in four cases: eel, smooth hound, starry smooth hound and tuna.

Maternal fish consumption, fetal growth and the risks of neonatal complications: the Generation R Study

Maternal fish consumption during pregnancy has been suggested to affect birth outcomes. Previous studies mainly focused on birth outcomes and did not study fetal growth during pregnancy. In a prospective cohort study from early pregnancy onwards in The Netherlands, we assessed the associations of first-trimester maternal total-fish, lean-fish, fatty-fish and shellfish consumption with fetal growth characteristics in the second and third trimesters, growth characteristics at birth and the risks of neonatal complications, including pre-term birth, low birth weight and small for gestational age. In total, 3380 mothers completed a 293-item semi-quantitative FFQ to obtain information about fish consumption during the first trimester of pregnancy. Head circumference, femur length and fetal weight were estimated in the second and third trimesters by ultrasound. Information about birth anthropometrics and neonatal complications was available from hospital and midwife registries. Maternal older age, higher educational level, folic acid supplement use, alcohol use and not smoking were associated with higher fish consumption (P < 0·01). After adjustment, we observed no consistent associations of maternal total-fish consumption or specific consumption of lean fish, fatty fish or shellfish with fetal growth characteristics in the second and third trimesters and at birth. Likewise, total-fish consumption or specific consumption of any type of fish was not consistently associated with the risks of neonatal complications. These findings suggest that in a population with a relatively low fish intake, consumption of lean fish, fatty fish or shellfish in the first trimester is not associated with fetal growth or the risks of neonatal complications.

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

The DR-H4IIE.Luc bioassay is based on the ability of dioxin and dioxin-like contaminants to activate the AhR and its signal transduction pathway, a mechanism through which these contaminants elicit their toxic effects. The bioassay was used to examine the total dioxin-equivalent (TEQ) toxicity in gonads and livers of cod females from the southern Baltic Sea. The bioassay-derived TEQ-luc was measured after 24-h and 48-h exposure periods. Mean concentrations in the 24-h bioassay were 95 and 35 pg TEQ-luc g(-1) lipid in gonads and livers, respectively, and 58 and 38 pg TEQ-luc g(-1) lipid in the 48-h bioassay, respectively. The 48-h TEQ-luc levels displayed significant relationships with ΣPCB(7) and selected PCB congeners but not with the TEQ(DLPCB-REP). Levels in gonads approached 10% of the LC50 for developing larvae of other marine fish, yet the impact on survival of the cod during its early life remains to be assessed in a future.

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.

Halogenated contaminants in farmed salmon, trout, tilapia, pangasius, and shrimp

Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane diastereomers (HBCDs), and perfluorinated compounds (PFCs) were analyzed in popular farmed fish such as salmon, trout, tilapia, and pangasius and in farmed shrimp. The samples originated from southeast Asia, Europe, and South America. Results show the following: (i) Carnivorous species contained higher contaminant concentrations than omnivorous species. (ii) Contaminant concentrations generally decreased per species in the following order of salmon > trout >> tilapia approximately equal to pangasius approximately equal to shrimp. (iii) Most contaminant concentrations decreased in the following order of PCBs approximately equal to dichloro-diphenyl-trichloroethanes (DDTs) >> hexachlorobenzene approximately equal to pentachlorobenzene approximately equal to dieldrin approximately equal to PBDEs approximately equal to alpha-HBCD approximately equal to perfluorooctane sulfonate (PFOS) >> World Health Organization toxic equivalents (WHO-TEQ) [PCDD/Fs and dioxin-like (dl)-PCBs]. (iv) Contaminant concentrations were very low (mostly <1 ng/g wet weight) and far below the European and Dutch legislative limits. (v) Contaminant concentrations in farmed shrimp, pangasius, and tilapia were lower than those in wild fish, whereas contaminant concentrations in farmed salmon and trout were higher than those in lean wild marine fish. From the five species investigated, salmon is predominantly responsible (97%) for human exposure to the sum of the investigated contaminants. The contribution of trout, tilapia, pangasius, and shrimp is small (3%) because contaminant concentrations and consumption volumes were much lower.

Prolonged ELS test with the marine flatfish sole (Solea solea) shows delayed toxic effects of previous exposure to PCB 126

The effect of the dioxin-like PCB 126 (3,3',4,4',5-pentachlorobiphenyl) on the early development of the marine flatfish sole (Solea solea) was tested in a newly developed early life stage (ELS) test that includes the metamorphosis of the symmetric larvae into an asymmetrical flatfish. Early life stages of sole were exposed to a concentration series of PCB 126 in seawater until 4, 8, 10 and 15 days post fertilisation (dpf). Subsequently the development of the larvae was registered under further unexposed conditions. The LC50s at the start of the free-feeding stage (12 dpf) ranged between 39 and 83 ng PCB 126/l depending on exposure duration. After the fish had completed the metamorphosis, the LC50 values ranged between 1.7 and 3.7 ng PCB 126/l for the groups exposed for 4, 8 and 10 dpf, respectively. Thus exposure for only 4 days, covering only the egg stage, was sufficient to cause adverse effects during a critical developmental phase two weeks later. The internal dosages of these larvae, determined by means of an in vitro gene reporter assay as dioxin-equivalent values (TEQ), revealed a LD50 of 1ng TEQ/g lipid, which is within the same order of magnitude as TEQ levels found in fish from highly polluted areas. This study indicates that ELS fish tests that are terminated shortly after the fish becomes free-feeding, underestimate the toxic potential of compounds with low acute toxicity such as PCBs. Our prolonged ELS with this native marine flatfish suggests that reproductive success of fish populations at contaminated sites can be affected by persistent compounds that are accumulated by the female fish and passed on to the eggs.

Brominated flame retardants in fish and shellfish - levels and contribution of fish consumption to dietary exposure of Dutch citizens to HBCD

In order to determine the contamination with brominated flame retardants (BFR) in fish regularly consumed by Dutch citizens, 44 samples of freshwater fish, marine fish, and shellfish were analyzed for polybrominated diphenyl ethers (PBDE), tetrabromobisphenol-A (TBBP-A) and its methylated derivative (me-TBBP-A), and hexabromocyclododecane (HBCD), including its alpha-, beta- and gamma-diastereomers. The highest BFR concentrations were found in pike-perch and eel from the highly industrialized and urbanized rivers Rhine and Meuse. The sum concentrations of BDE 28, 47, 99, 100, 153, 154, 183, 209, and brominated biphenyl (BB) 153 and HBCD (selection based on The European Food Safety Authority monitoring recommendation) ranged from below quantification limits to 17 ng/g wet weight (ww) in marine fish and in freshwater fish from 0.6 ng/g ww in pike-perch to 380 ng/g ww in eel. The BDE congener profile in all fish and shellfish samples is dominated by BDE 47, followed by BDE 99, except for eel in which BDE 100 is higher than BDE 99. BDE 209 was detected in two mussel samples, most likely due to BDE 209 contaminated particulate matter in their intestines. Total-HBCD (as determined by GC/electron capture negative ion (ECNI)-MS) was detected in 22 out of the 44 samples in concentrations between 0.20 ng/g in marine fish and 230 ng/g ww in eel. Three HBCD diastereomers were determined by HPLC/ESI-MS/MS. alpha-HBCD was the prevalent congener in most fish samples, followed by gamma-HBCD. beta-HBCD, TBBP-A and me-TBBP-A were only detected in a few samples and at low concentrations. A considerable difference was found between HBCD results obtained from GC/ECNI-MS and HPLC/ESI-MS/MS: the GC/ECNI-MS results were 4.4 times higher, according to regression analysis. There is hardly any data on human dietary exposure to HBCD available. We have estimated the fish-related dietary exposure of HBCD for the average Dutch population. The medium bound intake was estimated at 8.3 ng/day for a 70-kg person (0.12 ng/kg bodyweight/day). For this estimation, we relied mostly on HPLC/ESI-MS/MS data as we argue that these results are more accurate than those obtained by GC/ECNI-MS.

Modeling of DR CALUX bioassay response to screen PCDDs, PCDFs, and dioxin-like PCBs in farm milk from dairy herds

A recent issue in the EU legislation is the evaluation of the toxicologically-equivalent contribution of dioxin-like polychlorobiphenyls (DL-PCBs) in addition to that coming from polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) as contaminants in foods for a total of 29 congeners. This fact is determining the need to revise analytical criteria both for confirmatory and screening analysis. In this work, a modeling was developed to check the reliability of the outcomes of the DR CALUX bioassay when applied to farm milk samples characterized by large differences in congener patterns. To reproduce some field conditions where DL-PCB contributions up to 90% of total WHO-TEQs (HRGC-HRMS assessment) were recorded in dairy products, goat milk samples from a common bulk were fortified at different TEQ levels with mixtures containing either PCDDs and PCDFs or non-ortho substituted DL-PCBs. Fortification ranged approximately 4.5-15 pgWHO-TEQ/g fat. Based on the results, DR CALUX relative potency value (REP) of DL-PCB 126 was estimated 0.061 against the canonical WHO-TEF of 0.1. The value of 0.061 together with the other DR CALUX REPs from the literature for the remaining 28 congeners were used to model DR CALUX response (C-TEQs) in milk samples with different congener patterns. The theoretical underestimation of DR CALUX data could be mitigated by correcting the latter with the linear correlation experimentally obtained between C-TEQs and the WHO-TEQs. Under these conditions, the use as calibrants of reference samples with different analytical patterns could help those laboratories involved in a high throughput routine to set the most appropriate decision limits to optimize screening output.