Screening of hydrophobic DNA adducts in flounder (Platichthys flesus) from the Baltic Sea

Neoplasia and other histopathological lesions in flounder (Platichthys flesus) liver have been investigated in several European sea areas, including the Baltic Sea. Several studies have been able to link neoplasm epizootics in fish with the exposure to genotoxins such as polycyclic aromatic hydrocarbons (PAHs). The level of hydrophobic DNA adducts in tissue DNA reflects the exposure of the organism to PAHs.Using hydrophobic DNA adduct levels as biomarkers, possible PAH exposure was assessed in flounder from 10 different sites in the Baltic Sea, collected during the years 1995–1997. The results show that the overall levels of hepatic DNA adducts were low and, in general, the chromatograms appeared clean. The highest levels of DNA adducts were found at two sites in the southern Baltic Sea. There were no statistically significant differences in adduct levels between the sites. Our results indicate that flounder from studied off shore sites of the Baltic Sea had not been exposed to a greater extent to large polycyclic hydrophobic hydrocarbons in their environment.     

Responses of the European flounder (Platichthys flesus) to a mixture of PAHs and PCBs in experimental conditions

A multibiomarker approach was developed to evaluate the juvenile European flounder responses to a complex mixture of 9 polycyclic aromatic hydrocarbons (PAHs) and 12 polychlorinated biphenyls (PCBs). Exposure was performed through contaminated food pellets displaying: (1) PAH and PCB levels similar to those detected in the heavily polluted Seine estuary, respectively in sediments and in flatfish and (2) ten times these concentrations. Several biomarkers of the immune system (e.g., lysozyme concentration and gene expression of complement component C3 and TNF-receptor), DNA damage (e.g., Comet assay), energetic metabolism (e.g.,?activity of cytochrome C oxidase), detoxification process (e.g., cytochrome P450 1A1 expression level: CYP1A1; betaine homocysteine methyl transferase expression level: BHMT) were investigated after 14 and 29 days of contamination, followed by a 14-days recovery period. After 29 days of contamination, the detoxification activity (CYP1A1 expression level) was positively correlated with DNA damages; the increase of the BHMT expression level could also be related to the detoxification process. Furthermore, after the recovery period, some biomarkers were still upregulated (i.e., CYP1A1 and BHMT expression levels). The immune system was significantly modulated by the chemical stress at the two concentration levels, and the lysozyme appeared to be the most sensitive marker of the mixture impact.     

Frequency of hepatocellular fibrillar inclusions in European flounder (Platichthys flesus) from the Douro River estuary,Portugal

Liver lesions in wild fish have been associated with xenobiotic exposure. Facing reports of pollution in the Douro River estuary (north of Portugal), we have been making field surveys using fishes and targeting histopathological biomarkers of exposure and effect. Herein, we intended to better characterize and report the rate of one poorly understood lesion—hepatocellular fibrillar inclusions (HFI)—found in European flounder (Platichthys flesus). With this report, we aimed to establish sound baseline data that could be viewed as a starting point for future biomonitoring, while offering the world's second only pool of field data on such a liver toxicopathic lesion, which could be compared with data available from the UK estuaries. Sampling was done in the Douro River estuary over 1 year. A total of 72 animals were fished with nets, in spring–summer (SS) and autumn–winter (AW) campaigns. Livers were processed for histopathology and both routine and special staining procedures (alcian blue, periodic acid Schiff (PAS), tetrazonium coupling reaction). Immunohistochemistry targeted AE1/AE3 (pan cytokeratins). The severity of the HFI extent was graded using a system with four levels, varying from 0 (absence of HFI) to 3 (high relative density of cells with HFI). Cells (isolated/groups) with HFI appeared in 35 % or more of the fish, in the total samples of each season, and over 40 % in more homogeneous sub-samples. There were no significant differences when comparing samples versus sub-samples or SS versus AW. When merging the data sets from the two seasons, the frequency of fish with HFI was ≈36 % for the total sample and ≈49 % for the sub-sample. The extreme group (biggest and smallest fish) revealed a HFI frequency of only 16 %, which differed significantly from the total and sub-sampled groups. Immunostaining and PAS were negative for the HFI, and alcian blue could, at times, faintly stain the inclusions. These were positive with the tetrazonium reaction. We showed the presence of HFI in European flounder from the Douro River estuary, proving that they are essentially protein in nature, that no seasonal changes existed in the HFI frequency, and that it was rarer in the smallest and biggest fish groups. Within the ranges of weight/size of our total sample, we estimate that the frequency of HFI in the local flounder is ≈35 %. That rate stands as a baseline value for future assessments, namely for biomonitoring purposes targeting correlations with the estuary pollution status.     

Mercury in flounder (Platichthys flesus L.) from estuaries and coastal waters of the north-east Irish Sea

This paper reports concentrations of mercury in muscle tissue of flounder (Platichthys flesus L.) from various estuaries and coastal waters of north Wales and north-west England that encompass the north-east Irish Sea. Mercury concentrations were highest within and offshore the Ribble Estuary (0.476 +/- 0.037 mg kg(-1)) but were also high within the Mersey (0.389+/-0.042 mg kg(-1)) and Dee Estuaries (0.295+/-0.065) and at coastal sites in the vicinity. Values for all three estuaries and their near coastal sites were significantly higher than for sites in the north and central sectors of the study area. Regressions of mercury concentration against fish length showed significant relationships and age accumulation for the majority of sites, particularly within or in close proximity to the Mersey, Dee and Ribble Estuaries.     

Responses of juvenile European flounder (Platichthys flesus) to multistress in the Vilaine estuary, during a 6-month survey

Physiological and genetic responses of age 0+ Platichthys flesus were investigated in the eutrophicated and moderately contaminated Vilaine estuary, during a 6-month survey. The main objective of this study was to explore the biological responses of fishes during their juvenile period in an estuarine system in order to detect a possible selective pressure induced by the environmental stress. Our results showed a general convergence in physiological responses along the survey: an increase in genotoxicity was associated with an increase in mRNA expression of ATPase and betaine homocysteine methyltransferase. These results could suggest an increase of cellular damage, energetic request, and detoxification rate related to the growing exposure time to stress. Considering the aging of the cohort, the genetic characteristics of the Vilaine flounder cohort came closer to the one observed in a highly stressed system, the Seine estuary, suggesting a potential selective pressure mainly induced by the chemical stress.     

Comparison of biomarker and pathological responses in flounder (Platichthys flesus L.) induced by ingested polycyclic aromatic hydrocarbon (PAH) contamination

This study investigated the response of biomarker measurements and histopathological indicators of polycyclic aromatic hydrocarbon (PAH) exposure in the flounder (Platichthys flesus L.). Flounder were fed food spiked with a mixture of four PAHs at an environmentally relevant range of concentrations for either one or six months. Ethoxyresorufin-O-deethylase (EROD) activity was elevated following 1 month exposure to PAH concentrations up to 50 mgkg(-1) in food. Bile metabolite concentrations were found to increase with PAH concentration, up to 500 mgkg(-1) PAH. By comparison, no DNA adducts were detected and there were no significant histopathological changes observed. After 6 months exposure, EROD levels were not elevated but bile metabolites showed a similar dose dependent relationship as in the 1 month experiment, while DNA adducts were only detected in the highest PAH exposure groups. No significant histopathological changes were observed. The results are discussed with respect to the implications for the use of these methods in environmental monitoring studies.     

Toxicity of analytically cleaned pentabromodiphenylether after prolonged exposure in estuarine European flounder (Platichthys flesus), and partial life-cycle exposure in fresh water zebrafish (Danio rerio)

Residues of polybrominated diphenylethers (PBDEs), extensively applied as flame retardants, are widely spread in the aquatic environment and biota. The present study investigates effects of the environmentally relevant lower brominated diphenylethers in two fish species in vivo under controlled laboratory conditions. Euryhaline flounder (Platichthys flesus) and freshwater zebrafish (Danio rerio) were exposed to a range of concentrations of a commercial pentabromodiphenylether mixture, DE-71. Chemical analysis of exposed fish showed a pattern of PBDE congeners that was very similar to that in wild fish. The resulting range included environmentally relevant, as well as higher levels. Animals were investigated histopathologically with emphasis on endocrine and reproductive organs. In zebrafish, hatching of embryos and larval development were assessed. Biochemical parameters were investigated in flounder as markers for suggested dioxin-like activity (ethoxyresorufin-O-deethylase=EROD), and activation of endogenous estrogen synthesis (gonad aromatase activity). Thyroid hormones were analyzed in plasma in both species. Benchmark analysis using internal PBDE concentrations showed a mild dose-dependent decrease of hepatic EROD and ovarian aromatase activities, and plasma thyroxin levels in flounder, and an increase of plasma thyroid hormone levels in zebrafish. These trends did not result in statistically significant differences from control fish, and major histopathological changes were not observed. Reproduction in zebrafish appeared to be the most sensitive parameter with statistically significantly reduced larval survival and non-significant indications for decreased egg production at internal levels that were more than 55 times the highest environmental recordings. The present results indicate limited risk for endocrine or reproductive effects of current environmental PBDE contamination in fish.     

Trace metals in flounder, Platichthys flesus (Linnaeus, 1758), and sediments from the Baltic Sea and the Portuguese Atlantic coast

Trace metals were examined in the muscle tissue of flatfish species of flounder, Platichthys flesus (Linnaeus, 1758), sediments from two southern Baltic Sea sites (Gdańsk Bay and Ustecko-?ebskie as a reference) and in two areas of the Portuguese Atlantic coast (Douro River estuary and Atlantic fishing ground as a reference) to evaluate spatial differences in trace metals. Additionally, the accumulation of trace metals in flounder of different length classes was assessed. Flounder from the Gdańsk Bay area contained twofold more cupper (Cu), lead (Pb) and mercury (Hg) than did flounder from the Douro River estuary, but zinc (Zn) and cadmium (Cd) were at similar concentrations. The sediments from Gdańsk Bay contained significantly more Zn and threefold more Cd, while concentrations of Cu and Pb were twofold lower. The concentrations of metals in the sediments did not correlate with those in the flounder. Spatial differences were noted in metal concentrations in flounder from the southern Baltic Sea and the Portuguese Atlantic coast as well as within these regions, with higher concentrations in the flounder from the Baltic Sea Gdańsk Bay. The flounder in length class 25–30 cm from Gdańsk Bay contained metal concentrations comparable to those of class 40–45 cm specimens from the Atlantic coast. The accumulation of metals in flounder length classes differed in the two regions.     

Low hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity and minor alterations in retinoid and thyroid hormone levels in flounder (Platichthys flesus) exposed to the polychlorinated biphenyl (PCB) mixture, Clophen A50

The effect of the polychlorinated biphenyl (PCB) mixture Clophen A50 on hepatic cytochrome P4501A1 dependent EROD (7-ethoxyresorufin-O-deethylase) activity, plasma thyroid hormone levels and plasma, kidney and liver retinoid concentrations of the euryhaline flatfish flounder (Platichthys flesus) was determined 2 and 10 days after i.p. (intraperitoneal) injection with 20, 100 and 500 mg Clophen A50/kg body weight. No effect of Clophen A50 on total cytochrome P450 content in flounder liver was observed at both time points. A six-fold, dose-dependent, significant increase in EROD activity was found at exposure day 10 in flounder receiving 100 or 500 mg Clophen A50/kg body weight. Plasma retinol concentrations were not altered at both time points after Clophen A50 administration, whereas renal retinol levels showed a minor dose-related increase at day 2 and day 10 of exposure. Significant alterations in hepatic retinoid concentrations were observed, which were not dependent on the dose of PCB administered. In addition Clophen A50 administration did not result in a dose-related alteration of total T4 concentrations in plasma. Total T3 concentrations in plasma were only significantly increased at day 2 after exposure, whereas free T4 concentrations were increased at both time points after Clophen A50 administration. These data indicate that with regard to the parameters investigated and in contrast to other fish species studied, the flounder is not a sensitive species to PCB exposure.     

Histopathological lesions and DNA adducts in the liver of European flounder (Platichthys flesus) collected in the Seine estuary versus two reference estuarine systems on the French Atlantic coast

An epidemiological survey was conducted in the Seine estuary and in two smaller and relatively preserved estuaries on the French Atlantic coast in order to estimate the occurrence of liver lesions in European flounder, Platichthys flesus, and also to seek putative risk factors for the recorded pathologies. Four hundred and seventy-eight fish of both sexes and of different size ranges were sampled in the three studied areas, 338 of which in the Seine estuary. All fish were examined for histopathological liver lesions, while DNA adducts and otoliths were analyzed on a subsample. Five categories of hepatic lesions were recorded with the following prevalence for the Seine estuary: 36.7 % inflammations, 8 % parasites (mainly encysted nematodes), 6.5 % foci of cellular alteration (FCA), 5.3 % foci of necrosis or regeneration (FNR), and 1.5 % tumors. Inflammation occurrence increased according to age, contrary to parasitic infestations and FCA which were more prevalent in young fish, notably those of <1 year old (group 0). Tumors were only observed in females of more than two winters. Females exhibited a higher prevalence of tumors (3.0 %) and FCA (6.5 %) than males (0 and 2.6 %, respectively). Parasitic and infectious lesions and FNR were equally distributed in males and females. The prevalence of FNR was also shown to vary according to sampling season, with significantly more occurrences of liver necrosis in the fish collected in summer than in spring. Spatial differences were observed with a higher occurrence of encysted parasites in flounders from the upper Seine estuary, while inflammations predominated in flounders living downstream. Temporal trends were also noted, with an increased prevalence of parasitic infestations, inflammations, and FCA in the 2002–2003 period in comparison to the 1996–1997 one. The three flounder populations from the Seine estuary (Normandy), Ster estuary (Brittany), and Bay of Veys (Normandy) showed different spectra of hepatic lesions. Flounders from the Bay of Veys had relatively few liver lesions as compared to flounders from the two other estuaries. Flounders from the Ster estuary exhibited the highest prevalence of parasites (37.2 %) and inflammations (51.1 %). Finally, FCA and liver tumors occurred at very similar levels in both flounder populations from the Seine and the Ster estuaries. Group 0 flounders inhabiting the upper Seine estuary were more prone to parasitic and pre-neoplastic hepatic lesions and had higher levels of liver DNA adducts than the older ones living downstream. It was postulated that group 0 European flounders may serve as valuable bioindicators for assessing the quality of estuarine waters and the health status of euryhaline fish populations.     

Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: the case of the European flounder (Platichthys flesus) in the Bay of Biscay

The objective was to describe and model variation patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty-seven adult European flounders were collected in two seasons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocarbons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration–tumour, steatosis, inflammation, abnormal glycogen storage). Canonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homogeneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contaminated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contamination. The links between the load of contaminants, the expression of several genes and the biomarkers were analysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary.     

PAH Metabolites in Bile Fluids of Dab (Limanda limanda) and Flounder (Platichthys flesus): Spatial Distribution and Seasonal Changes (7 pp)

Background, Aim and Scope Polycyclic aromatic hydrocarbons (PAH) are important environmental contaminants which may lead to increased levels of neoplastic aberrations or tumours in fish liver. Therefore, monitoring of PAH and their effects are part of several international environmental programmes. The aim of the present field study was to investigate the concentrations of the PAH metabolites in fish bile, to elucidate spatial, seasonal and species differences as well as to discuss different strategies of normalisation with regard to environmental monitoring. Materials and Methods: PAH metabolites were determined in the bile fluid of dab (Limanda limanda) and flounder (Platichthys flesus) caught in the North Sea and Baltic Sea between 1997 and 2004. After enzymatic deconjugation, two metabolites were determined by means of HPLC. The limit of detection and the limit of quantification were calculated. The accuracy of the method was tested with a standard reference material. Results were referred to bile volume as well as to biliverdin. Results: The main metabolite, 1-hydroxypyrene, was determined in concentrations from <0.7 to 838 ng/ml in bile of dab (Limanda limanda) and flounder (Platichthys flesus) caught between 1997 and 2004. The values for 1-hydroxyphenanthrene in fish bile were considerably lower (<0.4 – 87 ng/ml). Significant differences in the 1-hydroxypyrene levels were found between summer and winter surveys as well as between the sampling sites in the data set from 2004 (383 dabs and 62 flounders): Highest levels of PAH contamination were found in dab from the German Bight and in flounder from the Baltic Sea. Discussion: Spatial differences in 1-hydroxypyrene concentrations between North Sea and Baltic Sea were discussed, as well as differences in relation to season, sex and species. Three parameters of normalisation (biliary protein, biliverdin and bile pigments) were discussed. Biliverdin was identified as a suitable parameter for the normalisation of PAH metabolites in field samples. Conclusions: Spatial differences in 1-hydroxypyrene concentrations of dab demonstrate the usefulness of PAH metabolites in fish bile as a monitoring parameter in marine regions. Significant differences in 1-hydroxypyrene concentrations were found between summer and winter sampling campaigns. This may be linked to an annual cycle of 1-hydroxyprene in dab. It is also possible that bile synthesis/release in dab differs between the seasons. There is no indication for a time trend from 1997 to 2004. Recommendations and Perspectives: It is recommended to relate PAH metabolites in fish bile to biliverdin concentrations. Although the concentrations are low in offshore regions and bile volumes are small, the method presented here allows one to measure PAH metabolites on an individual level which is a crucial prerequisite for meaningful monitoring studies.     

Organochlorine contaminants in northeast Atlantic minke whales (Balaenoptera acutorostrata)

Blubber samples of 72 minke whales (Balaenoptera acutorostrata) were obtained from the northeast Atlantic in July and August 1992, and evaluated for organochlorine contamination. The following organochlorines were determined: the industrial chemicals PCBs (polychlorinated biphenyls), and the organochlorine pesticides DDTs (dichlorodiphenyltrichloroethanes), HCHs (hexachlorocyclohexaneb), HCB (hexachlorobenzene) and CHLs (chlordanes). The concentrations of SigmaPCB (sum of concentrations of 18 PCB congeners) and SigmaDDT (sum of concentrations of p,p'-DDT, p,p'-DDE, p,p'-DDD, o,p'-DDT and o,p'-DDD) ranged from 0.6-20.8 and 0.5-14.8 microg g(-1) lipid weight, with mean concentrations at 3.8 and 2.5 microg g(-1) lipid weight, respectively. The mean concentrations of HCB, the chlordane metabolites oxychlordane, cis-chlordane and trans-nonachlor, and the HCH isomers (alpha-, beta- and gamma-HCH) were all < 1 microg g(-1) lipid weight. Significantly higher concentrations of the three major pollutants (SigmaPCB, SigmaDDT and SigmaCHL) were found in mature males as compared to mature females and juveniles of both sexes. No such relationship was found for SigmaHCH and HCB. Stomach contents of northeast Atlantic minke whales indicate considerable heterogeneity in the diet when comparing different years, seasons and geographical areas. However, without knowing more about the minke whale migration pattern, or possible geographical segregation with age and sex, the interchemical variation of organochlorines between sampling areas may not reflect true geographical differences.     

Organochlorine contaminants in Morelet's crocodile (Crocodylus moreletii) eggs from Belize

Non-viable eggs of Morelet's crocodile (Crocodylus moreletii) were collected from Gold Button (GBL) and New River lagoons (NRL) in northern Belize and screened for organochlorine (OC) compounds using gas chromatography (GC) with electron capture detection (ECD). All egg samples from both lagoons (n = 24) tested positive for one or more OCs. Primary contaminants were p,p-DDE and methoxychlor, detected in 100% and 29% of the eggs examined, respectively. Concentrations of individual OC contaminants ranged from 1 ppb (ng chemical/g egg) to > 0.5 ppm (microgram chemical/g egg). Total concentrations of OCs (sum of all OCs) for one egg collected from a nest at GBL reached as high as 0.7 ppm. Sediment samples from both lagoons also tested positive for OCs (lindane, aldrin, methoxychlor, heptachlor epoxide, p,p-DDT, among others). Nest media (soil and plant material) collected from crocodile nests at GBL were positive for p,p-DDT, methoxychlor, aldrin, endosulfan II, and endrin aldehyde. Based on the 24 egg samples analyzed to date, crocodiles from both lagoons are being exposed to OCs. Such exposure may present a health threat to populations of crocodiles in Central America.     

Organochlorine contaminants in narwhal (Monodon monoceros) from the Canadian Arctic

Organochlorine pesticides (DDT, chlordane, polychlorinated camphenes (PCCs), dieldrin, hexachloroheclohexanes (SigmaHCH), mirex), polychlorinated biphenyl congeners (PCBs) and chlorobenzenes (SigmaCBz) were determined in blubber and liver of narwhal (Monodon monoceros) collected during 1982-1983 from Pond Inlet on northern Baffin Island in the Canadian Arctic. PCCs were the predominate organochlorines in narwhal blubber, ranging in concentration from 2990 to 13 200 ng g(-1) (wet wt) in males and from 1910 to 8390 ng g(-1) in females. PCCs consisted of two major components, an octachlorobornane and a nonachlorobornane with gas chromatographic retention times of 1.05 and 1.22, relative to 4,4'-DDE. SigmaPCB concentrations in blubber ranged from 2250 to 7290 ng g(-1) in males and from 894 to 5710 ng g(-1) in females. Seven PCB congeners (tetra-, penta- and hexachlorobiphenyls) accounted for 45% of total PCB (SigmaPCB) in narwhal blubber. Narwhal had 1.4- to 8.6-fold higher ratios of tetra- and pentachlorobiphenyls to PCB-153 (2,2',4,4',5,5'-hexachlorobiphenyl), lower 4,4'-DDE/SigmaDDT ratios and lower proportions of trans-nonachlor to total chlordane components than reported for odontocetes living in more contaminated environments. Mean SigmaPCB concentrations in narwhal were 6- to 15-fold lower than in dolphins from the Canadian east coast and belugas from the St Lawrence River estuary, respectively, while PCC levels were from 4- to about 2-fold lower, and SigmaHCH, dieldrin and SigmaCBz differed by <2-fold. The pattern of organochlorines in narwhal tissues suggests they are exposed to proportionally more volatile compounds, and may have less capacity to metabolize some of these compounds, relative to odontocetes living nearer sources of these contaminants.     

水体中17种持久性和可迁移有机污染物的检测

持久性和移动性有机污染物 (persistent and mobile organic contaminants, PMOCs) 在环境中降解缓慢,并且可以通过水体循环进行迁移。由于缺乏水体中PMOCs的高效富集和准确测定方法,导致关于PMOCs在水体中存在水平的可靠监测数据较少。通过优化固相萃取条件和高效液相色谱-串联质谱参数,建立了同时检测水中17种PMOCs的分析方法。采用HLB固相萃取柱对水样中的PMOCs进行富集,乙腈和含10 mmol·L⁻¹乙酸铵的水溶液作为流动相进行梯度洗脱,PMOCs检出限为0.04~0.35 ng·L⁻¹,定量限为0.13~1.16 ng·L⁻¹,回收率为65.01%~98.65%。在北京潮白河、广东北江和河北滹沱河进行布点采样,并测定其PMOCs的质量浓度。实验结果表明：17种PMOCs在潮白河、北江和滹沱河中均有检出,其ƩPMOCs平均质量浓度分别为604.69、740.45和505.11 ng·L⁻¹。潮白河地表水中安赛蜜、金刚烷胺和己内酰胺的质量浓度相对较高,分别高达261.75、143.84和153.71 ng·L⁻¹。北江中安赛蜜、磷酸三 (2-氯丙基) 酯和己内酰胺的质量浓度相对较高,分别高达433.14、444.46和108.76 ng·L⁻¹。滹沱河中金刚烷胺、己内酰胺和磷酸三 (2-氯丙基) 酯的质量浓度较高,分别高达218.10、101.14和222.60 ng·L⁻¹。本研究结果可为地表水和地下水水体中PMOCs的检测评价提供参考。     

Aquatic leeches (Hirudinea) as bioindicators of organic chemical contaminants in freshwater ecosystems

Freshwater leeches from an industrially polluted creek were found to contain very high residues of chlorophenols, when compared with fish, tadpoles and most other benthic invertebrates. Leeches are recommended as possible bioindicators of aquatic organic contamination.     

Organochlorinated contaminants in decapod crustaceans from the coasts of Brittany and Normandy (France)

The contamination and distribution of organochlorinated compounds were considered in three crustacean species (edible crab, Cancer pagurus; spider crab, Maja brachydactyla; velvet swimming crab, Necora puber) from five sites along the coasts of Brittany and Normandy (Western and North-Western France). PCBs (16 single congeners), pp'-DDE and HCB were measured in hepatopancreas, gonads and muscle: in all, 175 samples were analysed. The spider crab was the only species found in the five sampling sites, thus enabling comparison between areas. Specimens from Antifer were much more contaminated (summation operator 16 PCBs in hepatopancreas=2000-4000 ng g(-1) dry weight) than those from other sites (50-1000 ng g(-1) d.w.). Among all the three species, the spider crab appeared more contaminated by PCBs than the edible crab, by a factor 2-3, probably in relation with specific differences in their life cycle. There was no difference due to the gender of the species. Within the different analysed tissues, contamination levels increased from muscle to gonads and hepatopancreas in relation with the fat content. A very similar PCB composition was observed in all samples, PCB fingerprints being characterised by the relative importance of the more persistent PCB congeners: CB153, 138, 180, 187, and 118. Finally, these results were compared to recent food regulations first of maximum marker PCB intake and secondly of maximum dioxin-like PCB intake. By considering the muscle, all samples were far below the regulatory limits; for hepatopancreas and gonads, however, some samples were unfit for human consumption.     

Organochlorine contaminants in complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs from Belize

Seven complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs were collected in northern Belize and examined for organochlorine (OC) pesticide residues. The primary OC detected, p,p-DDE, was found in every egg analyzed (n=175). Other OCs detected included p,p-DDT, p,p-DDD, methoxychlor, aldrin, and endosulfan I. Concentrations of individual OCs ranged from 4 ppb (ng chemical/g egg wet weight) to greater than 500 ppb. A statistical evaluation of p,p-DDE levels in three complete clutches was used to derive the minimum number of eggs needed from a clutch to precisely determine the mean p,p-DDE concentration representative of that clutch. Sample sizes of 8 (80% confidence level) and 11 (90% confidence level) were determined to yield an accurate estimate of contaminant levels in a full clutch of eggs. The statistically recommended sample size of 11 eggs (at 90% confidence level) was successfully tested on the four additional clutches.     

Within- and among-clutch variation of organohalogenated contaminants in eggs of great tits (Parus major)

In this study we investigated the variation of organohalogenated compounds, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs), within and among clutches of a small insectivorous songbird, the great tit (Parus major), and determined whether egg laying order affects the concentrations of these compounds. PCBs were the major organohalogenated contaminants in the eggs of great tits (mean 4778 ng/g lipid weight), while PBDEs (mean 204 ng/g lipid weight) and DDTs (mean 601 ng/g lipid weight) were found at much lower concentrations. Within-clutch variability of PCBs, PBDEs, and DDTs residues in the egg samples was small (7%, 3%, and 22%, respectively) compared to among-clutch variability (93%, 97%, and 78%, respectively). The small within-clutch variability may be in part related to the small home range of great tits and low spatial heterogeneity of the contaminants. We found no laying order effects on the concentrations of PCBs, PBDEs, and DDTs. Our results show that random egg samples of great tits are suitable as a biomonitoring tool for contamination with persistent organohalogenated pollutants in terrestrial environments.