Bioaccumulation Profiles Research Articles

Investigation of bioaccumulation profile of oestrogens in zebrafish liver by hollow fibre protected liquid phase microextraction with gas chromatography–mass spectrometric detection

The applicability of hollow fibre protected liquid phase microextraction (HF-LPME) for the determination of three oestrogens, namely estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from individual zebrafish liver samples, in a bioaccumulation study on these organisms, is reported. The oestrogens were extracted from single, mechanically crushed and minced livers from fish that were heaved in tubes containing water spiked at low concentration of the analytes. Extraction was performed with ∼3μL of toluene contained in the hollow fibre. In order to achieve high extraction efficiency, the parameters that could affect the effectiveness of HF-LPME were optimized, i.e. the extracting organic solvent, extraction time, stirring speed and pH of the aqueous phase. For gas chromatography/mass spectrometry (GC/MS) analysis, injection port derivatization of the oestrogens with bis(trimethylsilyl)trifluoroacetamide was conducted. Under the most favourable extraction and derivatization conditions, enrichment factors of 158–279 were obtained. Linearity of the HF-LPME–GC/MS method was evaluated from 1 to 50μg/L and the coefficient of determination (r2) ranged from 0.9687 to 0.9926. The LODs were between 0.017 and 0.033μg/L (at a signal to noise ratio of 3) with relative standard deviations (RSDs, analytes spiked at 5μg/L) of between 15 and 17% (n=3).

Distinct bioaccumulation profile of pesticides and dioxin-like compounds by mollusk bivalves reared in polluted and unpolluted tropical bays: Consumption risk and seasonal effect

Mariculture activity has increased its production along the Atlantic Coast of Brazil over the last years. This protein source for human consumption may also represent risks due to the exposure to bioaccumulated contaminants in the tissues of organisms reared in polluted shallow waters. This study evaluated the bioaccumulation of pesticides and dioxin-like compounds in two commercial marine bivalve species reared at different sites along the Rio de Janeiro State coast (SE-Brazil). We observed distinct contamination profiles in bivalve tissues reared at each sampling site, which may be related to human activities historically developed in those areas. A pronounced tendency for higher contamination levels in animals sampled in the last month of winter (September) is discussed as being likely due to environmental issues, rather than biological factors. Based on Minimal Risk Level, Maximum Residue, Acceptable Daily Intake and Toxic Equivalent, bivalves are classified as safe for human consumption.

Organohalogen compounds in deep-sea fishes from the western North Pacific, off-Tohoku, Japan: Contamination status and bioaccumulation profiles

Twelve species of deep-sea fishes collected in 2005 from the western North Pacific, off-Tohoku, Japan were analyzed for organohalogen compounds. Among the compounds analyzed, concentrations of DDTs and PCBs (up to 23,000 and 12,400ng/g lipid wt, respectively) were the highest. The present study is the foremost to report the occurrence of brominated flame retardants such as PBDEs and HBCDs in deep-sea organisms from the North Pacific region. Significant positive correlations found between δ15N (‰) and PCBs, DDTs and PBDEs suggest the high biomagnification potential of these contaminants in food web. The large variation in δ13C (‰) values observed between the species indicate multiple sources of carbon in the food web and specific accumulation of hydrophobic organohalogen compounds in benthic dwelling carnivore species like snubnosed eel. The results obtained in this study highlight the usefulness of deep-sea fishes as sentinel species to monitor the deep-sea environment.

Profiles of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Fish Livers and Gills from Dongting Lake, China

Dongting Lake is located in the northeastern part of Hunan Province in the People’s Republic of China. The lake covers about 2,740 km 2 , making it the second-largest freshwater lake in China. The lake is an important source of freshwater fish. However, it is also an endemic region of schistosomiasis. Oncomelania hupensis gredler is the only lodging host of schistosome and plays a vital role in schistosomiasis spread. To kill Oncomelania hupensis gredler large amounts of sodium pentachlorophenate (NaPCP), which was found containing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) impurities, had been sprayed for over 30 years (Bao et al., 1995). PCDD/Fs are chemically stable, persistent hydrophobic organic chemicals and are thought to be biomagnified via the food chain. Those isomers with chlorinated substitutions in the 2, 3, 7, and 8 positions are thought to pose a risk to human health due to their toxicity, carcinogenic potency, and potential effects on animal reproductive and immunological systems. Although the spraying of Na-PCP has been prohibited in the region since 1996, recent studies have indicated that the sediments, soils, and breast milk around Dongting Lake area are contaminated by PCDD/Fs (Zheng et al., 1997; Gao et al., 2005; Zheng et al., 2003). Fish are usually used as bioindicators for the environmental medium and food webs, and can reflect the PCDD/ Fs contaminant status. Moreover, humans are consumers of fish, and exposure assessments now routinely consider fish ingestion as a potential route of human exposure to chemicals in the environment. Consequently, monitoring programs establish limits for the maximum content of these toxicants in a variety of foods. An important regulation is that the European Community (EC) has set a limit of 4 pg/g wet weight of toxic equivalents (WHOPCDD/F-TEQ) for the muscle meat of fish and fishery products (EC, 2001). As do most organic contaminants, PCDD/Fs accumulate in certain organs with the highest proportions found in the fish liver (Wu et al., 2001). This paper describes the levels and bioaccumulation profiles of PCDD/Fs in different fish species livers and gills from Dongting Lake region.

Polychlorinated biphenyl (PCB) exposure assessment by multivariate statistical analysis of serum congener profiles in an adult Native American population

The major determinants of human polychlorinated biphenyl (PCB) body burden include the source and route of exposure and the toxicokinetic processes occurring after uptake. However, the relative importance of each factor for individual subjects cannot currently be determined. The present study characterizes levels and patterns of PCB congeners in a large cohort of adult Akwesasne Mohawks with historical PCB exposure. Total serum PCB ranged from 0.29 to 48.32 ng/g and was higher in adult men than in women (median of 3.81 vs. 2.94 ng/g). The mean serum congener profile for the full cohort was dominated by persistent penta- to hepta-chlorinated biphenyls; several labile congeners were also prominent. In order to provide additional information on individual body burden determinants, multivariate exploratory data analysis techniques were applied to the congener-specific serum PCB data. A self-training receptor model, polytopic vector analysis (PVA), was employed to determine the number, composition, and relative proportions of independent congener patterns that contributed to the overall serum PCB profile for each Mohawk subject. PVA identified five such patterns, each of which was characterized by a unique mix of congeners. One pattern observed in a limited number of Mohawks was similar to those reported for air sampled near contaminated sediment deposits at Akwesasne and for volatilized Aroclor 1248 and is hypothesized to reflect recent inhalation exposure in these subjects. A second pattern was consistent with unaltered Aroclor 1254. A third pattern, resembling Aroclor 1262 but without labile congeners, was correlated with age and is interpreted as representing a lifetime PCB accumulation profile. The final two patterns were dominated by subsets of major persistent congeners and are hypothesized to reflect intermediate bioaccumulation profiles and/or differences in individual toxicokinetics. The results confirm the utility of a multivariate exploratory analysis approach to congener-specific PCB data and provide additional insight into the exposure and individual factors that determine PCB body burden in this population.

Bioaccumulation Profiles of Chemical Contaminants in Fish from the Lower Willamette River, Portland Harbor, Oregon

Twenty-five PCBs (polychlorinated biphenyls), 15 organochlorine (OC) pesticides, and mercury were determined in fish from the Willamette River in Oregon, including a Portland Harbor superfund site. Fish were collected during the summer of 2000 along a 20-mile stretch of the lower Willamette River. Concentrations of sumPCBs (sum of 25 individually determined PCB congeners) and sumDDTs (sum of p,p'-DDT, p,p'-DDE, and p,p'-DDD) in fish ranged from 14 to 530 and from 18 to 510 ng/g-wet weight, respectively. SumPCBs concentrations at all sites exceeded US EPA fish advisory's screening values. Hexachlorobiphenyl congener 153 was the most abundant of the PCBs detected and p,p'-DDE was the most abundant OC pesticide detected. Low levels of dieldrin were detected in fish at all sites with the highest concentration at the superfund site (4.6 ng/g-wet weight), while other OC pesticides tested were near or below detection limits (approximately 2 ng/g). In general, organic chemical contaminant concentrations were highest in fish from the superfund site and were lower further upriver. Smallmouth bass had the highest levels of OC compounds of three fish species examined. They also had the largest site-to-site variations whereas black crappie had little variation throughout the study area. Mercury levels in fish ranged from 13 to 520 ng/g. Historical fish residue data are limited from the Portland Harbor superfund site, what data is available is over a decade old, generally consisted of only a few fish (< or = 3) and analyses quantified only a few PCB congeners (< 3).

Bioaccumulation and toxic potencies of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in tidal flat and coastal ecosystems of the Ariake Sea, Japan.

Sediment and marine biota comprising several species of tidal flat and coastal organisms were analyzed for polychlorinated biphenyls (PCBs) including non- and mono-ortho coplanar congeners and polycyclic aromatic hydrocarbons (PAHs) to examine bioaccumulation profiles and toxic potencies of these contaminants. Concentrations of PCBs in tidal flat organisms ranged from 3.6 ng/g (wet wt) in clams to 68 ng/g (wet wt) in omnivore tidal flatfishes, a discernible trend reflecting concentrations and trophic levels. In contrast, PAHs concentrations were the highest in lower trophic organisms, such as crabs and lugworms from tidal flat, whereas those in coastal fishes, squid, and finless porpoises were less than detection limit. Greater bioaccumulation of PAHs was found in lugworms and crabs, which might be due to their direct ingestion of sediment particulates absorbed with PAHs. TCDD toxic equivalents (TEQs) were calculated for PCBs and PAHs in sediments and biota. PCBs accounted for a greater proportion of total TEQs (sum(TEQs): sum of TEQ(PCB) and TEQ(PAH)) in coastal and tidal flatfishes (>95%), while PAHs occupied a considerable portion of sum(TEQs) in sediment (>97%). Interestingly, TEQ(PAH) accounted for 37% and 81% of the sum(TEQs) in crabs and clams, respectively. Benzo[b]fluoranthene was the dominant contributor to TEQ(PAH) in both the species. Considering these observations, the environmental risks of PAHs may not be ignored in benthic tidal flat organisms due to their greater bioaccumulation through sediments.

Persistent organochlorine residues and their bioaccumulation profiles in resident and migratory birds from North Vietnam

Concentrations of persistent organochlorines (OCs), such as polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), and chlordane compounds (CHLs), were determined in whole-body homogenates of resident and migratory birds collected from the Red River estuary, North Vietnam, during March and October 1997. Contamination pattern was in the order of DDTs > PCBs > HCHs > CHLs > HCB in both resident and migratory birds. Residue concentrations, according to the feeding habit, showed little variability, which may reflect relatively similar trophic levels of the bird species analyzed. Resident birds accumulated greater concentrations of DDTs as compared to migrants. In contrast, HCH residues were greater in migratory species. Higher proportions of p,p'-DDT to total DDT concentrations were found in many species of residents and migrants, indicating recent exposure to technical DDT in northern Vietnam. Congener-specific PCB analysis showed the predominance of penta- and hexachlorobiphenyls in all the species analyzed. Estimation of hepatic microsomal enzyme activities suggested higher metabolic capacity for PCB congeners in shore birds from Vietnam as compared to higher-trophic predator birds and marine mammals. Comparison of OC residues in avian species in Asia-Pacific revealed that DDT residues in resident birds in North Vietnam are among the highest values reported for the countries surveyed, suggesting recent usage of DDT in Vietnam. Available data for birds, fish, and bivalves from the recent Asia-Pacific Mussel Watch Program suggested that Vietnam might be a potential source of DDT contamination in Asian developing countries. To our knowledge, this is the first study of the OC accumulation in avian species from Vietnam.

Bioaccumulation profiles of polychlorinated biphenyl congeners and organochlorine pesticides in Ganges river dolphins

AbstractIsomer‐specific concentrations of polychlorinated biphenyls (PCBs) including non‐, mono‐, and di‐ortho‐substituted congeners, DDT and its metabolites, hexachlorocyclohexane (HCH) isomers, chlordane compounds, and hexachlorobenzene (HCB) were determined in river dolphin blubber and prey fishes collected during 1993 through 1996 from the River Ganges in India. Concentrations of organochlorines were also measured in the milk and liver of dolphins, benthic invertebrates, and sediments. The DDTs and PCBs were the predominant compounds found in dolphin tissues and fish that comprise the diet of dolphins. Concentrations of DDTs and PCBs in the blubber of dolphins were in the range of 30 to 120 and 1.5 to 25 μg/g, lipid weight, respectively. Pentaand hexachlorobiphenyls collectively accounted for 68 to 80% of the total PCB concentrations in river dolphins. Hexachlorobiphenyl congener 138 (2,2′,3,4,4′,5′‐) was the most abundant in dolphin blubber and prey fishes. The isomer/congener pattern of PCBs and organochlorine pesticides suggested that there is less metabolism due to cytochrome P450 enzymes in Ganges river dolphins than in marine or terrestrial mammals. The mean 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin equivalents (TEQs) estimated in river dolphin blubber was greater than those that can cause adverse effects in mink. Comparison of organochlorine concentrations in river dolphins with those of the values reported for samples analyzed during 1988 through 1992 suggested that the contamination by these compounds has increased in the River Ganges.

Bioaccumulation profiles of polychlorinated biphenyls including coplanar congeners and possible toxicological implications in Baikal seal ( Phoca sibirica)

Isomer specific concentrations of individual polychlorinated biphenyls (PCBs) including toxic non- ortho (IUPAC 77, 126, 169), mono- ortho (105, 118, 156) and di- ortho (137, 138, 153, 180) coplanar congeners were determined in the blubber of 40 Baikal seals ( Phoca sibirica) and as their fish diet collected from Lake Baikal, Siberia. Residue levels of total PCBs in Baikal seals were noticeably high and comparable to those reported for seals from the North Sea, suggesting the recent usage of this compound in the watershed of Lake Baikal. Non-, mono-, and di- ortho coplanar congeners were also detected in Baikal seals and fish. An approach to estimate bioaccumulation profiles of PCB congeners revealed that the non- ortho PCBs, IUPAC 77, 126 and 169 seemed to be less persistent than other congeners. Furthermore, selective biotransformation of PCB congeners having either meta-para vicinal H atoms or both adjacent chlorinated meta-para and ortho-meta positions has been suggested. Comparison of 2,3,7,8-TCDD toxic equivalents (TEQ) of non-, mono- and di- ortho coplanar congeners in Baikal seals with those for other marine mammals suggested higher enrichment of mono- ortho congeners, particularly IUPAC 105 and 118, which contributed significantly to the total TEQs in Baikal seals. Results imply that the TCDD-like toxicity is relatively serious in Baikal seals, because of the enrichment of these toxic PCB congeners in tissues.

Biomonitoring aquatic pollution with feral eel ( Anguilla anguilla) I. Bioaccumulation: biota-sediment ratios of PCBs, OCPs, PCDDs and PCDFs

Samples of sediments and eel taken from six Amsterdam freshwater sites were analyzed for polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo- p-dioxins (PCDDs). Biota-sediment accumulation factors (BSAFs) were determined from levels in sediments [ng/g organic matter (OM)] and eel muscle tissues [ng/g lipid weight (LW)]. Bioaccumulation patterns were both site- and analyte-specific. Bioaccumulation of these persistent organic trace pollutants in eel is discussed, considering partitioning, uptake from contaminated water (bioconcentration) and food (biomagnification), clearance, and bioavailability. Trends in bioaccumulation profiles indicated the following. Levels of PCBs, DDTs, HCB, PCDFs and PCDDs in eel tissues appeared to be exposure related since they increased with increasing levels of pollution in sediments. High BSAF values indicated that biomagnification contributed significantly to the total bioaccumulation process for PCBs, DDTs and HCB. Higher BSAF values for the higher chlorinated PCBs might be due to a more efficient biomagnification of these congeners and to a selective metabolism of the lower chlorinated congeners. Bioaccumulation of HCHs, drins and heptachlor compounds was low in eel. Bioaccumulation of PCDF and PCDD congeners was extremely low in eel. BSAF values of these congeners decreased with increasing chlorine substitution. A large variation in BSAF values for most of the hydrophobic chemicals was observed between different sites. This suggests that bioaccumulation not only depends upon type of organism and analyte, but that site-specific factors should also be taken into account. This might be due to differences in bioavailability (including desorption kinetics) of the compounds or to differences in the diet of the fish when biomagnification is involved. Estimated PCB toxic equivalent values (TEQs) were higher than calculated PCDF/ D TEQs at the reference site. The opposite was found at the most polluted site.

Mechanisms of bioaccumulation in aquatic systems.

Bioaccumulation of contaminants in aquatic organisms occur via several routes, including absorption across the cuticle and respiratory surfaces and assimilation from ingested media. For many contaminants of environmental importance, bioaccumulation can be understood as a simple partitioning process in which contaminants accumulate in living organisms in proportion to their lipophilicity. However, there are a variety of biological and physical factors that can influence bioaccumulation and result in deviations from the expected steady-state distribution of contaminants. Key variables have been identified, although their influence alone and in combination on bioaccumulation have yet to be determined. Because risk assessment depends on having an accurate evaluation of contaminant fate and effects, it is imperative to understand how bioaccumulation profiles may be modified by these variables.