Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

Insights into tissue accumulation, depletion, and health risk assessment of clopidol in poultry

Clopidol is extensively used in livestock farming and residues of this antibiotic can persist in animal tissues, posing a risk to humans and the environment. In this study, we investigated the depletion of clopidol in various edible tissues of chickens (muscle, liver, kidney, fat, and eggs) using liquid chromatography-tandem mass spectrometry after the administration of a clopidol-contaminated diet (at 250 mg kg-1 for the high (1x) dose). After 14 d of exposure, the clopidol concentrations were highest in eggs (median: 9.83 mg/kg), followed by liver (3.56 mg/kg), kidney (3.01 mg/kg), muscle (1.56 mg/kg), and fat (0.727 mg/kg) at low exposure group, indicating that clopidol accumulated primarily in eggs rather than the other edible tissues. In addition, the maternal transfer ratios were estimated, and the transfer efficiencies of clopidol in muscle (egg-to-tissue ratio, ETR:1.81) and fat (2.06-58.2) were higher than those in liver (0.731-31.1) and kidney (0.832-38.9). Furthermore, we conducted a cumulative risk assessment for clopidol in edible chicken tissues using the hazard quotient (HQ) method. This assessment revealed that the exposure levels for Korean consumers pose an acceptable risk. However, for eggs from the 1x dose exposure group, the HQ values were greater than 1 for all age groups, particularly for young children (<18 y), suggesting that the higher daily consumption of eggs combined with the higher clopidol residues in eggs resulted in higher HQ values, which requires further attention. The findings of this study can assist in the management and monitoring of clopidol residues in chicken tissues and eggs.

Co-contaminants of microplastics in two seabird species from the Canadian Arctic

Through ingestion and subsequent egestion, Arctic seabirds can bioaccumulate microplastics at and around their colony breeding sites. While microplastics in Arctic seabirds have been well documented, it is not yet understood to what extent these particles can act as transport vehicles for plastic-associated contaminants, including legacy persistent organic pollutants (POPs), trace metals, and organic additives. We investigated the occurrence and pattern of organic and inorganic co-contaminants of microplastics in two seabird species from the Canadian Arctic - northern fulmar (Fulmarus glacialis) and black-legged kittiwake (Rissa tridactyla). We found that fulmars had higher levels of plastic contamination and emerging organic compounds (known to be plastic additives) than kittiwakes, whereas higher concentrations of legacy POPs were found in kittiwakes than the fulmars. Furthermore, fulmars, the species with the much larger foraging range (∼200 km), had higher plastic pollution and overall contaminant burdens, indicating that birds may be acting as long-range transport vectors for plastic-associated pollution. Our results suggest a potential connection between plastic additive contamination and plastic pollution burdens in the bird stomachs, highlighting the importance of treating plastic particles and plastic-associated organic additives as co-contaminants rather than separate pollution issues.

Insights into the toxicokinetic, tissue distribution and maternal transfer of polychlorinated dibenzo-p-dioxins/dibenzofurans in laying hens fed with dioxin-associated dietary

A controlled feeding experiment was conducted to investigate the toxicokinetic of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in laying hens. The laying hens were fed with fly ash contaminated diets to replicate the typical environment-feed-chicken transfer chain in China. Levels of PCDD/Fs rapidly increased in the pectoralis, adipose tissue, liver and blood of laying hens with daily ingestion of dioxin-associated diets during the 14-days exposure period, and then a gradual decrease was observed in the 28-days depletion period. The depletion rates (k_d) of the toxic equivalent of PCDD/Fs (TEQ_PCDD/Fs) were 0.043, 0.031 and 0.030 day^-1 for pectoralis, liver and adipose tissue in the high-exposure group, respectively. The k_d of individual PCDD/Fs in liver increased with the numbers of chlorine and n-octanol/water partition coefficient (logK_OW), indicating that lower chlorinated congeners had higher half-lives in liver. Decreasing ratios of liver to adipose tissue for PCDD/Fs (L/AT) throughout the experiment suggested a tendency of equilibrium partitioning between liver and adipose tissue. Congener-specific sequestration of PCDD/Fs in liver was revealed by the positive correlation between L/AT ratios and logK_OW. Physiological bioconcentration factors of PCDD/Fs were estimated at the end of exposure, indicating the preferential accumulation of hexachlorinated congeners in most tissues. Furthermore, maternal transfer of PCDD/Fs was positively correlated with logK_OW, implying that more lipophilic congeners were transferred to egg along with the lipid circulation.

Comparison of Dechlorane Plus Concentrations in Sequential Blood Samples of Pregnant Women in Taizhou, China

To develop an appropriate sampling strategy to assess the intrauterine exposure to dechlorane plus (DP), we investigated DP levels in sequential maternal blood samples collected in three trimesters of pregnancy, respectively, from women living in Taizhou. The median concentration of DPs (sum of syn-DP and anti-DP) in all samples was 30.5 pg g−1 wet-weight and 5.01 ng g−1 lipid-adjusted weight, respectively. The trimester-related DP concentrations were consistently strongly correlated (p < 0.01), indicating that a single measurement of DP levels could represent intrauterine exposure without sampling from the same female repeatedly; however, the wet-weight levels significantly increased across trimesters (p < 0.05), while the lipid-adjusted levels did not significantly vary. Notably, whether lipid-adjusted weight or wet-weight levels, the variation extent of DP across trimesters was found to be less than 41%, and those for other persistent organic pollutants (POPs) reported in the literature were also limited to 100%. The limitation in variation extents indicated that, regardless of the time of blood collection during pregnancy and how the levels were expressed, a single measurement could be extended to screen for exposure risk if necessary. Our study provides different strategies for sampling the maternal blood to serve the requirement for assessment of in utero exposure to DP.

Sex- and size-dependent accumulation of Dechlorane Plus flame retardant in a wild frog-eating snake Amphiesma stolata

Despite several studies having addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, there is still a dearth of information for reptiles in general and for snakes in particular. Here, we report the residue levels and trophic transfer of syn-, anti-, and anti-Cl₁₁-DP in a frog-eating snake-namely, the striped keelback snake Amphiesma stolata-from a DP hotspot in South China. The concentrations of syn-, anti-, and anti-Cl₁₁-DP in A. stolata ranged from 1.06-21.2, 2.13-21.5, and 0.16-10.6 ng/g lipid weight, respectively, with significantly higher levels in males compared with females. Statistical analysis showed that the concentrations of these chemicals were negatively correlated with body sizes (length and mass) of the snake. The fractional abundance of anti-DP (f_anti) did not significantly differ either between the sexes or between A. stolata and its diet (i.e., frogs). However, f_anti showed positive correlations with the snake's body size and negative correlations with ∑DP concentrations (summed concentrations of syn- and anti-DP), indicating that body size and DP residue levels are important factors influencing DP isomeric profiles in these snakes. Biomagnification factors estimated based on the relationship between A. stolata and frogs were 0.49 ± 0.01 (mean ± SE), 0.44 ± 0.09, and 1.79 ± 0.54 for syn-, anti-, and anti-Cl₁₁-DP, respectively, suggesting trophic dilution of syn- and anti-DP and a mild biomagnification of anti-Cl₁₁-DP from frogs to snakes.

Risk Characterization and Benefit-Risk Assessment of Brominated Flame Retardant in Commercially Exploited Freshwater Fishes and Crayfish of Lake Trasimeno, Italy

Among brominated flame retardants (BFRs), polybrominateddiphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were the most widely used in past decades. BFRs not being chemically bonded to polymers means they can easily leach from the products into the environment and bioaccumulate. Humans are exposed to flame retardants mainly through food consumption, especially fish and fish products. In the present study, the occurrence of PBDEs and HBCDs in freshwater fishes and crayfish from Lake Trasimeno (Umbria region, central Italy) was assessed according to monitoring plans recommended by European competent authorities. The dietary exposure of the central Italian population to such molecules was calculated, and the risk characterization and the benefit–risk evaluation were also assessed. A total of 90 samples were analyzed by means of gas and liquid chromatography associated with triple quadrupole mass spectroscopy. A total of 51% of samples were found positive for at least one of the congeners; the most frequently found molecule was BDE-47. The data on dietary exposure ranged from 0.138 to 1.113 pg/kg body weight/day for ∑PBDE and from 0.805 to 0.868 pg/kg body weight/day for ∑HBCD. The data show no health risks for the central Italian population consuming freshwater fish products from Lake Trasimeno in relation to exposure to PBDE and HBCD.

Maternal transfer of polychlorinated biphenyls in Pacific sand lance (Ammodytes personatus), Puget Sound, Washington

We measured polychlorinated biphenyls (PCBs) in multiple age and size classes of Pacific sand lance (Ammodytes personatus), including eggs, young-of-the year, and adults to evaluate maternal transfer as a pathway for contaminant uptake and to add to the limited information on the occurrence of PCBs in sand lance in Puget Sound. Sampling was replicated at an urban embayment (Eagle Harbor) and a state park along an open shoreline (Clayton Beach), during spring and fall. Lipid-normalized concentrations of PCBs in sand lance at Eagle Harbor were 5-11 times higher than PCB concentrations in comparable samples at Clayton Beach. This was true for every life stage and size class of sand lance, including eggs removed from females. The same trend was observed in environmental samples. In Eagle Harbor, PCB concentrations in unfiltered water (0.19 ng/L), sieved (<63 μm) nearshore bed sediments (0.78 ng/g dw) and suspended particulate matter (1.69 ng/g dw) were 2-3 times higher than equivalent samples from near Clayton Beach. Sand lance collected in the fall (buried in sediment during presumed winter dormancy) had lower lipid content and up to four times higher PCB concentrations than comparably sized fish collected in the spring (by beach seine). Lipid content was 5-8% in spring fish and was reduced in fall fish (1-3%). Male sand lance had higher PCB concentrations than comparable females. All egg samples contained PCBs, and the lipid normalized egg/female concentration ratios were close to 1 (0.87-0.96), confirming that maternal transfer of PCBs occurred, resulting in sand lance eggs and early life stages being contaminated with PCBs even before they are exposed to exogenous sources. These life stages are prey for an even wider range of species than consume adult sand lance, creating additional exposure pathways for biota and increasing the challenges for mitigation of PCBs in the food web.

Changes in Cadmium Concentration in Muscles, Ovaries, and Eggs of Silver European Eel (Anguilla anguilla) during Maturation under Controlled Conditions

This study determined the contents of cadmium (Cd) in the muscles, ovaries, and eggs of silver female European eels. The analysis of cadmium content was performed on female European eels caught during commercial fishing in freshwater in Warmia and Mazury (Poland), and then subjected to artificial maturation and ovulation processing under controlled conditions. The content of cadmium (Cd) in the tissues was determined by flameless atomic spectrometry using an electrothermal atomizer. The analysis showed statistically significant differences between the cadmium content in the muscles, ovaries, and eggs (p < 0.05) of female European eels. The lowest cadmium content was found in the muscle tissue (0.0012 ± 0.0001 mg kg-1 wet weight) and the highest in eggs (after ovulation) (0.0038 ± 0.0007 mg kg-1 wet weight). Moreover, a relationship was found between the cadmium content in the muscle tissue and the ovaries (R = 0.673; p = 0.0117) in the same fish. The movement of cadmium from tissues to oocytes may indicate a significant problem concerning this heavy metal content in the reproduction of European eel.

Assessment of the quality of European silver eels and tentative approach to trace the origin of contaminants - A European overview

The European eel is critically endangered. Although the quality of silver eels is essential for their reproduction, little is known about the effects of multiple contaminants on the spawning migration and the European eel management plan does not take this into account. To address this knowledge gap, we sampled 482 silver eels from 12 catchments across Europe and developed methods to assess three aspects of eel quality: muscular lipid content (N = 169 eels), infection with Anguillicola crassus (N = 482), and contamination by persistent organic pollutants (POPs, N = 169) and trace elements (TEs, N = 75). We developed a standardized eel quality risks index (EQR) using these aspects for the subsample of 75 female eels. Among 169 eels, 33% seem to have enough muscular lipids content to reach the Sargasso Sea to reproduce. Among 482 silver eels, 93% were infected by A. crassus at least once during their lifetime. All contaminants were above the limit of quantification, except the 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), Ag and V. The contamination by POPs was heterogeneous between catchments while TEs were relatively homogeneous, suggesting a multi-scale adaptation of management plans. The EQR revealed that eels from Warwickshire were most impacted by brominated flame-retardants and agricultural contaminants, those from Scheldt were most impacted by agricultural and construction activities, PCBs, coal burning, and land use, while Frémur eels were best characterized by lower lipid contents and high parasitic and BTBPE levels. There was a positive correlation between EQR and a human footprint index highlighting the capacity of silver eels for biomonitoring human activities and the potential impact on the suitability of the aquatic environment for eel population health. EQR therefore represents a step forward in the standardization and mapping of eel quality risks, which will help identify priorities and strategies for restocking freshwater ecosystems.

Sex-Specific Bioamplification of Halogenated Organic Pollutants during Silkworm (Bombyx mori) Metamorphosis and Their Adverse Effects on Silkworm Development

A partial life cycle test was performed with silkworms (Bombyx mori) exposed to different levels of halogenated organic pollutants (HOPs). The aims were to investigate the fate of HOPs during metamorphosis and the adverse effects of HOP exposures on silkworm development. Contaminant exposures resulted in decreased body weights, increased development times, and reductions of fecundity in silkworms. Assimilation efficiencies of HOPs decreased with an increasing octanol-water partition coefficient (log K_OW). From the larvae to the pupae stage, bioamplification factors (BAmFs) exhibited concentration-dependent results, in which there was a positive correlation with the log K_OW at the high concentrations but no correlation at the low concentrations. From the pupae to the moth stage, BAmFs were linearly negatively correlated with the log K_OW for males, but a parabolic correlation with the log K_OW was more suitable for females. Regarding reproductive activities, female moths selectively transferred low log K_OW HOPs to eggs by the oviposition except for highly halogenated lipophilic pollutants. However, BAmFs of male moths during mating showed no correlation with the log K_OW, although highly halogenated lipophilic pollutants had the highest BAmF values. The sex-specific bioamplification processes and special behaviors of highly halogenated lipophilic pollutants deserve further research.

Legacy and emerging persistent organic pollutants in the freshwater system: Relative distribution, contamination trends, and bioaccumulation

In this study, a comprehensive investigation was performed to understand the overall occurrence, relative distribution, and bioaccumulation of seven different groups of POPs, comprising 27 polybrominated diphenyl ethers (PBDEs), 76 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), three hexabromocyclododecanes (HBCDs), and 13 perfluoroalkyl substances (PFASs) as legacy POPs, and 41 polychlorinated naphthalenes (PCNs) and 24 short-chain chlorinated paraffins (SCCPs) as emerging POPs, by monitoring crucian carp, sediment, and river water in the freshwater system. Among the targeted POPs, SCCPs were predominant in sediment and crucian carp (more than 95%), while a dominance of PFASs was observed in river water (92%). Principal component analysis revealed four different groups/patterns of POPs in all media: one for PBDEs, PCBs, and OCPs, another for HBCDs and PFASs, and the two others for PCNs and SCCPs. Also, sexually dimorphic growth-dependent accumulation of legacy POPs was observed in crucian carp such that POPs concentration increased with increasing fish size and males recorded significantly higher levels of POPs compared to females.

Occurrence, biomagnification and maternal transfer of legacy and emerging organophosphorus flame retardants and plasticizers in water snake from an e-waste site

Water snake and small common carp samples collected from a Chinese pond polluted with electronic waste (e-waste) were analyzed for organophosphorus flame retardants (PFRs), PFR metabolites, and plasticizers to investigate their occurrence, biomagnification, and maternal transfer in ovoviviparous species. Mean concentrations of total PFRs, PFR metabolites, and plasticizers were 2.2-16, 1.3-2.8 and 151-1320 ng/g wet weight (ww), respectively in analyzed organisms. Metabolites of PFRs were found in the same order of magnitude as or even higher than their parent compounds, indicating the importance of monitoring metabolites to evaluate the internal exposure of PFRs in organisms. Biomagnification factors (BMFs) were below 1 for all targeted chemicals and negatively correlated with metabolite/parent ratios (MPRs), suggesting a biodilution driven by metabolism. The lipid normalized concentrations were lower in eggs than in muscle for most of targeted chemicals. The maternal transfer potential was significantly and positively correlated with log K_OW (p < 0.05) when log K_OW was below 6.

Assessment of Dechlorane Plus and related compounds in foodstuffs and estimates of daily intake from Lebanese population

Dechlorane Related Compounds (DRCs), including Dechlorane Plus (syn/anti-DP or syn/anti-DDC-CO) and related compounds (Dec-601 or DDC-ID, Dec-602 or DDC-DBF, Dec-603 or DDC-Ant and Chlordene Plus or DDC-PDD), are a group of polychlorinated flame retardants of concern since they were first reported in various environmental and biota matrices about one decade ago. In this work, we investigated the dietary intake of the Lebanese population to these lipophilic environmental contaminants upon the evaluation of selected foodstuff contamination. Collected food samples (n = 58) were selected to be representative of the lipid fraction of the whole diet of the Beiruti population. The samples were analysed using pressurized liquid extraction, silica multilayer column followed by gel permeation chromatography for purification and GC-EI-HRMS for separation and detection. Detection frequency of at least one compound among Dechlorane Plus (syn-DP and anti-DP), Dechlorane 602, 603 and Chlordene Plus) was 91%. The mean concentrations of ∑₆DRCs, by food group, ranged from 4.7 to 29.5 pg g^-1 wet weight in lowerbound (LB) and from 6.7 to 76.9 pg g^-1 wet weight in upperbound (UB). Based on food habits, the dietary intake of Beiruti adults was estimated to be between 3.71 (LB) and 5.61 (UB) ng day^-1. Dechlorane Plus and Dechlorane 602 were the dominant compounds, contributing to 70 and 24% of the total intake (LB value), respectively. This study reports for the first time the occurrence of Dechloranes in Lebanese foods and proposes corresponding deterministic dietary exposure scenario.

Bone resorption and body reorganization during maturation induce maternal transfer of toxic metals in anguillid eels

During their once-in-a-lifetime transoceanic spawning migration, anguillid eels do not feed, instead rely on energy stores to fuel the demands of locomotion and reproduction while they reorganize their bodies by depleting body reserves and building up gonadal tissue. Here we show how the European eel (Anguilla anguilla) breaks down its skeleton to redistribute phosphorus and calcium from hard to soft tissues during its sexual development. Using multiple analytical and imaging techniques, we characterize the spatial and temporal degradation of the skeletal framework from initial to final gonadal maturation and use elemental mass ratios in bone, muscle, liver, and gonadal tissue to determine the fluxes and fates of selected minerals and metals in the eels' bodies. We find that bone loss is more pronounced in females than in males and eventually may reach a point at which the mechanical stability of the skeleton is challenged. P and Ca are released and translocated from skeletal tissues to muscle and gonads, leaving both elements in constant proportion in remaining bone structures. The depletion of internal stores from hard and soft tissues during maturation-induced body reorganization is accompanied by the recirculation, translocation, and maternal transfer of potentially toxic metals from bone and muscle to the ovaries in gravid females, which may have direct deleterious effects on health and hinder the reproductive success of individuals of this critically endangered species.

Bioaccumulation of Selected Halogenated Organic Flame Retardants in Lake Ontario

The trophic magnification of polybrominated diphenyl ethers (PBDEs) and selected nonlegacy halogenated organic compounds (HOCs) was determined in the food web of Lake Ontario (ON, Canada). In all, 28 Br₃ -Br₈ -PBDEs and 24 HOCs (10 of which had not been targeted previously) were analyzed. Average concentrations of Σ₂₈ PBDEs in fish ranged between 79.7 ± 54.2 ng/g lipid weight in alewife (Alosa pseudoharengus) and 815 ± 695 ng/g lipid weight in lake trout (Salvelinus namaycush). For invertebrates, concentrations were between 13.4 ng/g lipid weight (net plankton; >110 μm) and 41.9 ng/g lipid weight in Diaporeia (Diaporeia hoyi). Detection frequency (DF) for HOCs was highest for anti-Dechlorane Plus (anti-DDC-CO), 1,3-diiodobenzene (1,3-DiiB), tribromo-methoxy-methylbenzene (ME-TBP), allyl 2,4,6-tribromophenyl ether (TBP-AE), pentabromocyclododecene (PBCYD), α+β-tetrabromocylcooctane (TBCO), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE), and pentabromotoluene (PBT; DF for all = 100% in lake trout). Tetrabromoxylene (TBX), dibromopropyl 2,4,6-tribromophenyl ether (TBP-DBPE), and syn-DDC-CO were also frequently detected in trout (DF = 70-78%), whereas 2,3,4,5,6-pentabromoethyl benzene (PBEB) was detected only in plankton. Several HOCs were reported in aquatic biota in the Great Lakes (USA/Canada) for the first time in the present study, including PBCYD, 1,3DiiB, BATE, TBP-DBPE, PBT, α + β-TBCO, and ME-TBP. The Br_4-6 -BDEs (-47, -85, -99, -100, -153, and -154) all had prey-weighted biomagnification factors (BMF_PW ) values >6, whereas BMF_PW values for Br_7-8 -BDEs were <1. The highest BMF_PW values of non-PBDEs were for TBP-DBPE (10.6 ± 1.34) and ME-TBP (4.88 ± 0.60), whereas TBP-AE had a BMF_PW value of <1. Significant (p ≤ 0.05) trophic magnification factors (TMFs), both positive and negative, were found for Br_4-8- BDEs (BDE 196 = 0.4; BDE 154 = 9.5) and for bis(2,4,6-tribromophenoxy)ethane (BTBPE; 0.53), PBCYD (1.8), 1,3-DiiB (0.33), and pentabromobenzene (PBB; 0.25). Food chain length was found to have a significant influence on the TMF values. Environ Toxicol Chem 2019;38:1198-1210. © 2019 SETAC.

Dechlorane Plus flame retardant in a contaminated frog species: Biomagnification and isomer-specific transfer from females to their eggs

While flame retardant Dechlorane Plus (DP) and its dechlorinated analogs have been frequently detected in wildlife, knowledge is limited on their bioaccumulation and maternal transfer in amphibians. In the present study, the occurrence of syn- and anti-DP isomers and a DP dechlorinated compound, anti-Cl₁₁-DP, were investigated in frogs and insects collected from the paddy field of a highly contaminated site. The concentrations of ∑DP (the sum concentrations of syn- and anti-DP) in the frog muscle, liver, and eggs were 141 ± 24.7, 454 ± 73.9, and 184 ± 31.1 ng/g lipid weight, respectively; with significantly higher levels in the males than females. The syn-, anti- and anti-Cl₁₁-DP were all detectable in the frog eggs, demonstrating their maternal transfer in female frogs. The concentration ratios between eggs and liver pairs were 0.49 ± 0.01, 0.35 ± 0.01, and 0.53 ± 0.06 for syn-DP, anti-DP, and anti-Cl₁₁-DP, respectively. The values of f_anti (the concentration of anti-DP relative to the sum concentration of DP) differed significantly between frog tissues (0.33-0.79) and insects (0.71-0.74), indicating isomer-specific bioaccumulation of DP in the frogs. The concentration ratios of the frogs to the insects were greater than 1 for all the DP-related compounds, suggesting a possibility of biomagnification of these chemicals in the frogs.

Halogenated organic pollutants in aquatic, amphibious, and terrestrial organisms from an e-waste site: Habitat-dependent accumulation and maternal transfer in watersnake

Dichlorodiphenyltrichloroethanes (DDTs), Polychlorinated biphenyls (PCBs), and halogenated flame retardants (HFRs) were measured in aquatic, amphibious, and terrestrial wildlife collected from an e-waste contaminated pond and its surrounding region. The species-specific bioaccumulation and maternal transfer of chemicals in the watersnake were investigated. Total concentrations of target chemicals ranged from 1.3 × 10³ to 4.8 × 10⁵ ng g^-1 lipid weight. PCBs were the predominant (72-95%) contaminants, followed by polybrominated biphenyl ethers (PBDEs, 4-27%). The concentrations of PCBs and HFRs except decabromodiphenyl ethane (DBDPE) were higher in aquatic organisms and terrestrial birds than in amphibians and lizards. Relatively high DDT levels were observed in the terrestrial birds and toads, but high DBDPE was found in the aquatic species except for waterbird eggs. Species-specific congeners profiles for PCB and PBDE and isomeric composition for dechlorane plus were observed. These results indicated a habitat-dependent accumulation among different species. Maternal transfer examined by the ratio of egg to carcass for watersnakes indicated multi-linear correlations between maternal transfer potential and octanol-water partition coefficient (log K_OW) of chemicals. The same maternal transfer efficiencies were found for chemicals with log K_OW between 6 and 8, then the maternal transfer potential rapidly decreased with increasing of log K_OW.

Biotransformation of tetrabromobisphenol A dimethyl ether back to tetrabromobisphenol A in whole pumpkin plants

As the metabolites of tetrabromobisphenol A (TBBPA), tetrabromobisphenol A mono- and di-methyl ethers (TBBPA MME and TBBPA DME) have been detected in various environmental media. However, knowledge of the contribution of plants to their environmental fates, especially to the interactions between TBBPA DME and TBBPA, is quite limited. In this study, the metabolism and behaviors of TBBPA DME was studied with pumpkin plants through 15-day hydroponic exposure. The TBBPA were also studied separately using in-lab hydroponic exposure for comparison. The results showed that more TBBPA DME accumulated in pumpkin roots and translocated up to stems and leaves compared with TBBPA. Transformation of TBBPA DME occurred later and more slowly than that of TBBPA. Interconversion between TBBPA DME and TBBPA was verified in intact plants for the first time. Namely, TBBPA DME can be biotransformed to TBBPA MME (transformation ratio in mole mass, TRMM 0.50%) and to TBBPA (TRMM 0.53%) within pumpkin; and TBBPA can be biotransformed to TBBPA MME (TRMM 0.58%) and to TBBPA DME (TRMM 0.62%). In addition, two single benzene-ring metabolites, 2,6-dibromo-4-(2-(2-hydroxyl)-propyl)-anisole (DBHPA, TRMM 3.4%) with an O-methyl group and 2,6-dibromo-4-(2-(2-hydroxyl)-propyl)-phenetole (DBHPP, TRMM 0.57%) with an O-ethyl group, were identified as the transformation products in the TBBPA exposure experiments. The transformation and interconversion from TBBPA DME back to TBBPA is reported as a new pathway and potential source for TBBPA in the environment.

Transchem project - Part I: Impact of long-term exposure to pendimethalin on the health status of rainbow trout (Oncorhynchus mykiss L.) genitors

Pendimethalin is a herbicide active substance commonly used in terrestrial agricultural systems and is thus detected at high concentrations in the surface water of several European countries. Previous studies reported several histopathological changes, enzymatic antioxidant modulation and immunity disturbance in fish exposed to this pesticide. The objective of this work was to investigate the direct effects of long-term exposure to environmental concentrations of pendimethalin over a period of 18 months in rainbow trout (Oncorhynchus mykiss) genitors. To do so, an experimental system consisting of eight similar 400 L tanks with a flow-through of fresh river water was used to perform daily chemical contamination. Fish were exposed to 850 ng/L for one hour and the pendimethalin concentration was then gradually diluted during the day to maintain optimal conditions for the fish throughout the experiment and to achieve a mean theoretical exposure level of around 100 ng L^-1 per day. Every November, males and females were stripped to collect eggs and sperm and two new first generations of offspring were obtained. Kinetic sampling revealed differences in immune system parameters and antioxidative defences in the contaminated trout compared to the controls, due to pesticide exposure combined with seasonal changes related to gamete maturation. Moreover, reproductive capacity was significantly affected by exposure to the herbicide; a time lag of more than five weeks was observed for egg maturation in contaminated females and high bioconcentrations of pendimethalin were measured in eggs and sperm. Chemical transfer from genitors to offspring via gametes may affect embryo development and negatively impact the early stages of development.

Tissue-specific distribution and bioaccumulation potential of organophosphate flame retardants in crucian carp

The concentrations, distributions, and bioaccumulation of nine organophosphate flame retardants (OPFRs) were investigated in both abiotic and biotic media, comprising river water, sediment, and crucian carp. The highest concentrations were observed in liver (6.22-18.1 ng/g ww), and the levels in muscle (4.23-7.75 ng/g ww) and gonad (3.08-7.70 ng/g ww) were similar. In whole blood, tris(2-butoxyethyl) phosphate (TBOEP; 31.1-256 ng/mL) accounted for 90% of the total OPFR concentration. Distributions of OPFRs differed between biotic and abiotic media, as tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and TBOEP were dominant in abiotic media, whereas triethyl phosphate (TEP), tri-n-butyl phosphate (TNBP), TCEP, and TBOEP dominated in crucian carp. The TNBP had remarkable accumulation potential among nine OPFRs, which the TNBP concentrations in muscle increased with increased total length and body weight. The higher perfusion rate of TNBP to female eggs were observed rather than to male gonads as the concentrations were higher in males than in females, while the opposite results were observed in gonad. Moreover, the concentration of TNBP in female muscle began to decrease near maximum growth as a sexually dimorphic difference in crucian carp. This is the first study to simultaneously investigate the fate of OPFRs in biotic and abiotic media and to show sex differences.

Dechlorinated Analogues of Dechlorane Plus

Degradation products of the chlorinated additive flame retardant Dechlorane Plus (DP) have been discovered globally. However, the identity of many of these species remains unknown due to a lack of available analytical standards, hindering the ability to quantitatively measure the amounts of these compounds in the environment. In the present study, synthetic routes to possible dechlorinated DP derivatives were investigated in an effort to identify the environmentally significant degradation products. The methano-bridge chlorines of anti- and syn-DP were selectively replaced by hydrogen atoms to give six new hydrodechlorinated DP analogues. The identity and absolute configuration of all of these compounds were confirmed by GC-MS, NMR spectroscopy, and X-ray diffraction studies. These compounds were observed in sediment samples from streams and rivers in relatively rural areas of Ontario and are thus environmentally relevant.

Emerging brominated flame retardants and dechlorane-related compounds in European eels (Anguilla anguilla) from Latvian lakes

Fifteen halogenated flame retardants (HFRs) including seven emerging brominated flame retardants (EBFRs) and eight dechlorane-related compounds (DRCs) were analyzed in eels (Anguilla anguilla) sampled from five Latvian lakes. Out of the seven EBFRs, hexabromocyclododecane (HBCD) and decabromodiphenyl ethane (DBDPE) were found in eels in quantifiable concentrations, up to 6.58 and 33.0 ng g^-1 lipid weight (l.w.), respectively. The mean total concentration of DRCs (∑_DRC) in the samples was 0.62 ng g^-1 l.w. and the geographical distribution of DRC contamination was nearly uniform among the selected lakes. Dechlorane 602 (Dec 602) was the predominant component, whereas the composition of mixture containing syn- and anti-Dechlorane Plus (DP) stereoisomers showed a pronounced enrichment of the anti-DP isomer and was close to the composition of OxyChem^® DP commercial product. The determined concentrations of HFRs were lower than in other studies of aquatic biota from Europe and Asia, and the obtained results reflect the acceptable environmental status of Latvian lakes with regard to the total content of HBCD (∑_HBCD), considering the environmental quality standards (EQS) stated in the Directive 2013/39/EU. The highest ∑_HBCD levels were observed in eels from lakes corresponding to the industrialization of those areas, while the results of principal component analysis (PCA) showed that the concentration of HBCD depended on the particular sampling lake, reflecting non-uniform contamination of the Latvian environment with this EBFR.

Stereoselective bioaccumulation of syn- and anti-Dechlorane plus isomers in different tissues of common carp (Cyprinus carpio)

Common carps (Cyprinus carpio) were exposed to syn- and anti-Dechlorane Plus (DP) isomers to investigate absorption, tissue distribution, and stereoselective bioaccumulation of DP isomers. The absorption efficiencies of anti-DP in the gastrointestinal system were higher than those of syn-DP. A linear accumulation was found for both isomers in all fish tissues except for serum; and the liver and gill exhibited the highest and lowest DP assimilation efficiency, respectively. The elimination of DP isomers in all tissues followed first-order kinetics, with the fastest depuration rate occurring in the liver and serum. The biomagnification factors (BMFs) of both isomers were less than one in all tissues, except for serum. Anti-DP was preferably accumulated in the liver, gill, and serum, whereas syn-DP was selectively accumulated in the carcass and gastrointestinal tract. As a whole, fish did not show selective accumulation of the syn- or anti-DP isomer in the uptake stage, whereas a selective accumulation of syn-DP in fish was observed during the depuration period, which could be due to a selective excretion of anti-DP. Metabolism cannot be ruled out as a possible reason considering the high f_anti values and the high elimination rate of DPs in the liver.

Maternal transfer of dioxin-like compounds in artificially matured European eels

Several eel species of the genus Anguilla are considered endangered due to a severe decline in recruitment. Up to now, the reasons for this threatening development are not fully understood. The eel's highly specialized biology can lead to explicitly high accumulation of globally distributed organic lipophilic contaminants during its continental life. Because of this and due the particular toxicological sensitivity of early life stages of oviparous organisms towards dioxin-like compounds, it is crucial to improve our understanding concerning toxicokinetics and maternal transfer of organic contaminants in eels. This study presents analytical data on maternal transfer of dioxin-like (dl) compounds in relevant tissue samples taken from artificially matured and non-matured European silver eels (Anguilla anguilla) from German inland waters using gas chromatography coupled with mass spectrometry (GC/MS) and high-resolution mass spectrometry (GC/HRMS). Detected concentrations revealed a lipid-driven transfer of targeted compounds from muscle-fat-reserves to gonads and eggs respectively, with no distinct preferences concerning the chlorination degree of targeted compounds. Dl-PCBs were shown to contribute the major share of toxicity equivalents found in analysed eel tissues. Maternal muscle tissue to egg concentration ratios in wet weight-based samples had a mean of 6.95 ± 1.49 in accordance with the differences in total lipid content in the respective body matrices. Dioxins and furans in analysed samples were (from a toxicological point of view) of less relevance. Furthermore it was shown that muscle concentrations in silver eels could be used in future assessments to make conservative predictions for expected egg concentrations in female eels.

Evidence for High Concentrations and Maternal Transfer of Substituted Diphenylamines in European Eels Analyzed by Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry and Gas Chromatography-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Chemical pollution is hypothesized to be one of the factors driving the strong decline of the critically endangered European eel population. Specifically, the impact of contaminants on the quality of spawning eels and subsequent embryo survival and development has been discussed as crucial investigation point. However, so far, only very limited information on potential negative effects of contaminants on the reproduction of eels is available. Through the combination of nontargeted ultrahigh-resolution mass spectrometry and multidimensional gas chromatography, combined with more-conventional targeted analytical approaches and multimedia mass-balance modeling, compounds of particular relevance, and their maternal transfer in artificially matured European eels from the German river Ems have been identified. Substituted diphenylamines were, unexpectedly, found to be the primary organic contaminants in the eel samples, with concentrations in the μg g^-1 wet weight range. Furthermore, it could be shown that these contaminants, as well as polychlorinated biphenyls (PCBs), organochlorine pesticides, and polyaromatic hydrocarbons (PAHs), are not merely stored in lipid rich tissue of eels but maternally transferred into gonads and eggs. The results of this study provide unique information on both the fate and behavior of substituted diphenylamines in the environment as well as their relevance as contaminants in European eels.

Persistent organic pollutants in Baltic herring (Clupea harengus)-an aspect of gender

Persistent organic pollutants (POPs) are monitored regularly in water, sediment, and biota in the Baltic Sea. Lipophilic substances are measured in remarkable concentrations especially in the fatty parts of fish, such as herring (Clupea harengus). However, less lipophilic POPs, e.g. perfluorinated compounds (PFCs), can also be detected. For the first time to our knowledge, this study provides a broad range of contaminant concentrations simultaneously measured in filet, liver, and gonads of both sexes of Baltic herring. We analysed organochlorines, polybrominated diphenyl ethers (PBDEs), and PFCs in mature autumn-spawning individuals and found distinct organ pollutant pattern for all POPs in both sexes. POP concentrations found in the gonads of both sexes indicate that not only females but also males tend to reduce contaminants via reproduction. However, sex-dependent differences could be identified for hexachlorobenzene, PBDEs, and were most remarkable for PFCs. This transfer of contaminants to the gonads in both male and female herring is being underestimated, as it may directly affect the general reproduction success as well as the healthy development of the next generation. Hence, the accumulation of contaminants in the gonads should be considered one possible threat to a healthy wildlife as its achievement is stated by the Baltic Sea Action Plan. Inclusion of a periodic monitoring of POP concentrations in gonads of fish may be an important bioeffect measure to assess the environmental status of biota in the Baltic Sea.

Maternal transfer of dechloranes and their distribution among tissues in contaminated ducks

The tissue concentrations of dechlorane plus and its analogues were determined in ducks collected from several e-waste recycling villages of Taizhou, China. Compared with the published literature, the relatively high concentrations of these compounds were detected in ducks, indicating serious DP contamination. Since both the duck meat and eggs were important components for diet, this result reminded us of keeping a watchful eye on human dietary exposure to DP and its analogues in this study area. The wet-weight concentrations of DP and its analogues were significantly related to tissue lipid content (p < 0.05), indicating that the lipid pools predominantly impacted the distribution of DPs in ducks. On the basis of lipid adjustment, the significantly lower levels in brain than those in liver and blood, displayed the occurrence of liver sequestration and blood-brain barrier to DP and its analogues in the duck (p < 0.05). The maternal transfer of DP and Mirex was not obviously limited, and the transferring extent of Dec 602 was over one. The stereo-selected accumulation of two DP isomers occurred among tissues with preference to syn-DP in blood, and to anti-DP in brain. The values of lipid-adjusted monodechlorinated products mainly originated from the exterior environment in ducks.

Determination of Dechlorane Plus and related compounds (dechlorane 602, 603 and 604) in fish and vegetable oils

Dechlorane Plus (DP) is a flame retardant used as a substitute of Mirex since 1970s, but it was not detected in the environment until 2006. Since then, this compound and its main relatives, Dechlorane 602, 603 and 604, have been mainly studied in environmental matrices for monitoring purposes, but the dietary exposure to them has been hardly investigated so far. In the present study, we determined this family of compounds in fish and vegetable oil samples from Catalonia (Spain), most of them used as health supplements. Determination was carried out by gas chromatography-high resolution mass spectrometry (GC-HRMS), after a clean up in a multilayer silica column and preparative high performance liquid chromatography (HPLC) equipped with a pyrenyl(ethyl) column. Concentrations of Dechlorane compounds were between below the limit of detection and 384.2 pg g(-1). Although there are only few studies about the presence of these pollutants in food or feed, concentrations obtained indicated that these compounds are in the same order in fish and vegetable oil health supplements as the few other food and feed studies.

Cryopreservation in fish: current status and pathways to quality assurance and quality control in repository development

Cryopreservation in aquatic species in general has been constrained to research activities for more than 60 years. Although the need for application and commercialisation pathways has become clear, the lack of comprehensive quality assurance and quality control programs has impeded the progress of the field, delaying the establishment of germplasm repositories and commercial-scale applications. In this review we focus on the opportunities for standardisation in the practices involved in the four main stages of the cryopreservation process: (1) source, housing and conditioning of fish; (2) sample collection and preparation; (3) freezing and cryogenic storage of samples; and (4) egg collection and use of thawed sperm samples. In addition, we introduce some key factors that would assist the transition to commercial-scale, high-throughput application.

A question of origin: dioxin-like PCBs and their relevance in stock management of European eels

The stock of European Eel (Anguilla anguilla L.) has reached an all-time low in 2011. Spawner quality of mature eels in terms of health status and fitness is considered one of the key elements for successful migration and reproduction. Dioxin-like Polychlorinated Biphenyls (dl-PCBs) are known persistent organic pollutants potentially affecting the reproductive capability and health status of eels throughout their entire lifetime. In this study, muscle tissue samples of 192 European eels of all continental life stages from 6 different water bodies and 13 sampling sites were analyzed for contamination with lipophilic dl-PCBs to investigate the potential relevance of the respective habitat in light of eel stock management. Results of this study reveal habitat-dependent and life history stage-related accumulation of targeted PCBs. Sum concentrations of targeted PCBs differed significantly between life stages and inter-habitat variability in dl-PCB levels and -profiles was observed. Among all investigated life stages, migrant silver eels were found to be the most suitable life history stage to represent their particular water system due to habitat dwell-time and their terminal contamination status. With reference to a possible negative impact of dl-PCBs on health and the reproductive capability of eels, it was hypothesized that those growing up in less polluted habitats have a better chance to produce healthy offspring than those growing up in highly polluted habitats. We suggest that the contamination status of water systems is fundamental for the life cycle of eels and needs to be considered in stock management and restocking programs.