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1.
Persistent organic pollutants in remote freshwater ecosystems   总被引：3，自引：0，他引：3  
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2.
We quantified the seasonal changes in the zooplankton abundances collected from the Huetzalin Lake (Mexico City, Mexico) for two years (February 2003–January 2004 and then March 2005–February 2006). Selected physicochemical variables (Secchi depth, temperature, pH, conductivity, dissolved oxygen, phosphorus, nitrogen, carbon and chlorophyll a concentration) were also measured at the time of zooplankton collection. The data on zooplankton abundances and the physicochemical variables were subjected to multiple correlation analysis and we also derived Shannon–Wiener species diversity index. Secchi depth ranged from 9 to 65 cm. Generally the lake was alkaline (pH 7–12). The conductivity ranged from 500–1000 mS cm−1, while the mean water temperature was 20.5 °C. Dissolved oxygen levels were generally >3 mg L−1 and were higher in the winter than warmer months. Nitrates (90–95 μg L−1) and phosphates (.2–.5 mg L−1) indicated that the water was eutrophic. Chlorophyll a levels ranged from 143 to 696 μg L−1 during the study period. The zooplankton community was dominated by rotifers (46 species), followed by cladocerans (9 species) and there were only two copepod species. The dominant rotifer species were Brachionus angularis, Brachionus calyciflorus, Brachionus havanaensis, Brachionus quadridentatus, Lecane bulla and Polyarthra vulgaris. Rare rotifer species in Lake Huetzalin were Lecane ohioensis, Dicranophorus forcipatus, Lecane pyriformis, Lindia torulosa, Pleurotrocha petromyzon and Brachionus durgae. Highest densities (occasional peaks of 400 ind L−1) of B. quadridentatus occurred between April and December, while B. havanaensis reached peak densities, during June to October. B. calyciflorus reached densities higher than 1240 ind L−1 during May–September. Cladoceran and copepod densities in Lake Huetzalin were much lower than that of the rotifers. This study confirmed the earlier findings that Xochimilco system of canals is dominated by rotifers and the crustacean zooplankton have much lower abundances possibly due to predation from fish.  相似文献   

3.
Polyfluorinated compounds (PFCs) were investigated in waste water treatment plant (WWTP) effluents and surface waters of the River Elbe from samples collected in 2007. Concentrations of various PFCs, including C4–C8 perfluorinated sulfonates (PFSAs), C6 and C8 perfluorinated sulfinates, 6:2 fluorotelomer sulfonate, C5–C13 perfluorinated carboxylic acids (PFCAs), C4 and C8 perfluoroalkyl sulfonamides and 6:2, 8:2 and 10:2 unsaturated fluorotelomercarboxylic acids were quantified. ∑PFC concentrations of the river water ranged from 7.6 to 26.4 ng L−1, whereas ∑PFC concentrations of WWTP effluents were approximately 5–10 times higher (30.5–266.3 ng L−1), indicating that WWTPs are potential sources of PFCs in the marine environment. PFC patterns of different WWTP effluents varied depending on the origin of the waste water, whereas the profile of PFC composition in the river water was relatively constant. In both kinds of water samples, perfluorooctanoic acid (PFOA) was the major PFC, whereas perfluorobutane sulfonate (PFBS) was the predominant PFSA.  相似文献   

4.
The distributions of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the aqueous phase, suspended particulate matter (SPM), sediment, and pore water of the Daliao River Estuary in Liaodong Bay, Bohai Sea (China). Total PAH concentrations ranged from 139.16 to 1717.87 ng L−1 in surface water, from 226.57 to 1404.85 ng L−1 dry weight in SPM, from 276.26 to 1606.89 ng g−1 dry weight in sediments, and from 10.20 to 47.27 μg L−1 in pore water. PAH concentrations were at relatively moderate levels in water, SPM, sediment and pore water in comparison with those reported for other estuary and marine systems around the world. Sedimentary PAH concentrations decreased offshore owing to active deposition of laterally-transported river-borne particles. PCA analysis of the possible PAH source suggested petrogenic and pyrolytic PAH inputs in the studied region.  相似文献   

5.
The distributions of dimethylsulfide (DMS) and its precursor, dimethylsulfoniopropionate (DMSP), were examined in the surface microlayer and corresponding subsurface water of the Yellow Sea, China, in April 2006. The average concentrations of DMS and DMSP of dissolved (DMSPd) and particulate (DMSPp) forms were 5.42 (1.78–12.75), 9.22 (2.85–19.73) and 17.50 (4.33–36.09) nmol L−1 in the subsurface water, and those in the surface microlayer were 4.92 (1.69–10.66), 17.08 (3.13–38.82) and 22.54 (4.85–47.24) nmol L−1, respectively. The enrichment factor (EF) of DMS in the microlayer ranged from 0.47 to 2.24 with a mean of 0.98. In contrast, DMSPd and DMSPp appeared to be enriched in the microlayer with average EFs of 1.98 and 1.39, respectively. A close correlation of integrated DMS, DMSPp and chlorophyll a concentrations for compiled data from all stations in the microlayer and the subsurface water indicated that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. Moreover, a statistically significant relationship was found between the microlayer concentrations of DMS, DMSP and chlorophyll a and their subsurface water concentrations, suggesting a close linkage between these two water compartments. Interestingly, we observed higher biological production rates and consumption rates of DMS in the microlayer relative to the subsurface water. Furthermore, the DMS production rates were closely correlated both with DMSPd and chlorophyll a concentrations. Our study showed that the major sink of DMS in microlayer was escape into the atmosphere, which greatly exceeded its bacterial consumption. A preliminary estimate for average flux of DMS from the Yellow Sea to the atmosphere was 6.41 μmol m−2 d−1 during spring.  相似文献   

6.
Specimens of Nassarius nitidus were collected in seven stations of the Venice Lagoon to assess the levels of tributyltin (TBT) and its metabolites monobutyltin and dibutyltin in the tissues and monitor their effect on organisms, in particular the phenomenon of imposex (superimposition of male sexual characteristics on females). The following values of population indices were found: vas deferens sequence: 1.2 ± 0.7–4.0 ± 0.5; relative penis length: 6–47%. The least impacted station was situated in the northern part of the Lagoon, where females without imposex were found and Butyltin (BuTs) concentrations in the organisms (average sum of BuTs = 43 ± 14 ng Sn g−1 w.) were significantly lower than in the other stations (range of average sum of BuTs: 101 ± 22–217 ± 27 ng Sn g−1 d.w.). Population indices were found to be related to the TBT content in the tissues. In particular VDSI had a significant logarithmic correlation: r = 0.95, n = 8, p < 0.05.  相似文献   

7.
Sediment traps were deployed in the Gulf of Papua in June–July 1997, to determine fluxes of organic matter and inorganic elements from the photic zone to deeper waters at the base of the continental slope and in the northern Coral Sea. Three stations, ranging from 900 to 1500 m depth, had “shallow” traps at 300 m below the water surface and “deep” traps set 100 m above the bottom. Infiltrex II water samplers collected particulate and dissolved organic matter from the Fly, Purari and Kikori rivers, and near-surface water from the shelf of the Gulf of Papua. Samples were analysed for molecular organic biomarkers to estimate the sources of organic carbon and its cycling processes.Dry weight fluxes from the shallow traps ranged from 115 to 181 mg m−2 day−1 and particulate organic carbon (POC) fluxes ranged from 1.2 to 1.9 mM OC m−2 d−1 with molar organic carbon to particulate nitrogen ratios (C/N) ranging from 6.0 to 6.5. Fluxes in deep traps were likely influenced by both early diagenesis and entrapment of resuspended shelf sediments. Dry weight fluxes in deep traps ranged from 106 to 574 mg m−2 day−1 and POC fluxes ranged from 0.6 to 1.5 mM OC m−2 d−1, with C/N ratios ranging from 8.5 to 10.8. 13C/12C ratios were −20.2‰ to −21.7‰ in all trap samples, indicating that most of the settling POC was “marine-derived”. Shallow traps had δ15N values of 6.3‰ to 7.2‰ while the values in deep traps were 4.9–5.0‰, indicating the N-rich near-surface OC was less degraded than that in the deep traps. The biogenic lipids consisted of hydrocarbon, sterol and fatty acid biomarkers indicative of marine zooplankton, phytoplankton and bacteria. Sterol markers for diatoms and dinoflagellates were abundant in the water samples. Highly branched isoprenoid alkenes, usually attributable to diatoms, were also detected in both water and shallow traps. Traces of C26–C34 n-alcohols indicative of land–plant biomarkers, were found in river water samples and in the shallow sediment traps. A large unresolved complex mixture (UCM) of hydrocarbons, and a uniform distribution of n-alkanes, indicative of petroleum hydrocarbons, were also detected in the traps. Hopane and sterane biomarkers detected in the trap oil were characteristic of a marine carbonate source, and the aromatic hydrocarbon composition distinguished at least two different oil signatures.We concluded that mass and POC fluxes were similar to those reported for other continental shelves and marginal oceans in tropical and subtropical regions. There was a dramatic decrease in POC as particles sank, due to zooplankton repackaging and photochemical and bacterial decomposition. Carbon isotopic and biomarker patterns showed most of the POC in the sediment traps was marine-sourced with only traces of terrestrial input. There was a significant flux of petroleum, which may signal the existence of natural petroleum seeps in this region.  相似文献   

8.
Mercury deposition histories have been scarcely documented in the southern hemisphere. A sediment core was collected from the ecologically important estuarine floodplain of the Berg River (South Africa). We establish the concentration of Hg in this 210Pb-dated sediment core at <50 ng g−1 HgT throughout the core, but with 1.3 ng g−1 methylmercury in surface sediments. The 210Pb dating of the core provides a first record of mercury deposition to the site and reveals the onset of enhanced mercury deposition in 1970. The ratio of methylmercury to total mercury is relatively high in these sediments when compared to other wetlands.  相似文献   

9.
The purpose of this study was to establish the distribution, speciation and bioavailability of mercury in mangrove sediments. A systemic survey of surficial sediments from 13 mangrove wetlands of China was carried out. Hg concentrations ranged from 2.3–903.6 ng g−1, with an average value of 189.4 ng g−1. Of the 13 areas surveyed, the Hg content in sediments was similar to background levels in 6 areas but was much higher in the other seven areas. Hg levels were affected by natural and anthropogenic factors, including terrestrial pollutants, geomorphic properties, and indirectly by economic status. Hg levels were positively correlated with organic matter, pH, and silt and clay fractions, but Hg was negatively correlated with sand fraction. In most mangrove wetlands, Hg existed primarily in the form of volatile Hg. Hg is easily bioaccumulated in mangrove wetlands and may be the natural source of Hg emissions to the atmosphere.  相似文献   

10.
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediment is an attractive remediation technique and its success depends on biodegradation kinetics, and the optimal condition for the PAH-degrading isolates; however, information on this aspect is still scarce. The effects of multi-factors on biodegradation of phenanthrene, a 3-ring model PAH, in contaminated sediment slurry by Sphingomonas sp. a bacterial strain isolated from surface mangrove sediment, were investigated using the orthogonal experimental design (form L16(45)). The most significant factors were salinity and inoculum size, while the effects of phenanthrene concentrations, nutrient addition and temperatures were insignificant. The optimal biodegradation condition in contaminated mangrove sediment slurry was 30 °C, 15 ppt salinity, a carbon/nitrogen ratio of 100:1 (the background ratio in sediment) and an inoculum size of 106 most probable number g−1 sediment. The phenanthrene biodegradation could be best described by the first order rate model, C = C0e−kt, where k (the rate constant) is equaled to 0.1185, under the optimal condition. The kinetic model was verified and its validity in predicting biodegradation by Sphingomonas sp. at various phenanthrene concentrations was proved by experimental data.  相似文献   

11.
Since it is often difficult to estimate possible adverse effects due to contamination in selected ecosystems, multi-species biomonitoring may provide more information, taking into account different routes of exposure, ecological roles and metabolic capabilities of animals. In this context, we exposed for 7 days the mussel Mytilus galloprovincialis and the crab Carcinus aestuarii to 4-nonylphenol (NP), a well-known xenoestrogen. In mussels (0–0.2 mg NP l−1), we measured NP bioaccumulation in soft tissues and vitellogenin (Vg)-like protein levels in digestive glands from both males and females by the alkali-labile phosphate assay (ALP). As no reference data were available for crab exposure, the NP 96-h LC50 value was previously determined. Then, in sublethally exposed (0–1.0 mg NP l−1) male crabs, NP bioaccumulation and Vg levels were measured in hemolymph, gonads and digestive gland. Bioaccumulation of NP increased from 43 to 371 μg g−1 d.w. in mussels, and from 3.6 to 37 μg g−1 d.w. in crabs, depending on the NP concentration in water. Dose-dependent Vg-like protein induction was observed in both species, appearing to be related to NP bioaccumulation, although a partial decrease was recorded at the highest concentration tested. A similar trend was observed in both digestive gland and gonad of exposed crabs; Vg increased to a lesser extent, although significantly, in hemolymph. Results demonstrated that NP induces Vg synthesis both in male and female mussels, as well as in male crabs. On the basis of the responsiveness of both species investigated, a multi-species approach is indicated in biomonitoring programmes.  相似文献   

12.
After the Hebei Spirit oil spill incident (7th December, 2007) in the west coast of Korea, contamination of biliary PAH metabolite and hepatic biomarkers in a pelagic and a benthic fish was monitored for 1 year. Concentrations of 16 PAHs and alkylated PAHs in fish muscle were highest (22.0 ng/g d.w. for 16 PAHs and 284 ng/g d.w. for alkylated PAHs) at 5 days after the spill and then decreased rapidly to background levels at 11 months after the spill. Fish from the oiled site had elevated biliary PAH metabolite concentrations immediately after the spill; these declined steadily in both species, but were still above reference site concentrations 2 months after the spill. Oiled-site fish showed hepatic CYP 1A induction whose trend closely followed those of biliary PAH metabolite concentrations, implying continuous exposure to PAHs. Brain acetylcholinesterase activity was not related to oil exposure.  相似文献   

13.
Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the presence and nature of polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons. The region receives treated produced waters through a submarine outfall system serving the industrial district. The total dispersed/dissolved concentrations in the water column ranged from 10-50 ng L−1 for ∑16PAH and 5-10 μg L−1 for total aliphatic hydrocarbons. In the sediments, hydrocarbon concentrations were low (0.5-10 ng g−1for ∑16PAH and 0.01-5.0 μg g−1 for total aliphatic hydrocarbons) and were consistent with the low organic carbon content of the local sandy sediments. These data indicate little and/or absence of anthropogenic influence on hydrocarbon distribution in water and sediment. Therefore, the measured values may be taken as background values for the region and can be used as future reference following new developments of the petroleum industry in the Potiguar Basin.  相似文献   

14.
After 1990, external loads of Central European rivers with inorganic nutrients (nitrogen and phosphorus) and organic material were reduced because of changed environmental laws. However, in the eutrophic lowland River Warnow, North-Eastern Germany, nitrate concentrations remained high with 35–185 μmol l−1 without a significant decrease since 1992. In contrast, phosphate concentrations, varying between 0.3 and 5.2 μmol l−1 during the growth season 2002, decreased significantly over the years. However, its concentrations still exceeded 1 μmol l−1 regularly in the growth seasons. This load led to a substantial accumulation of organic matter additional to high terrestrial inputs. Despite the high organic load, the remineralising bacteria were mainly inactive in River Warnow. Therefore, the composition of the dissolved organic material, especially its bioavailability, were investigated during the growth season 2002 and discussed with other potential controlling factors. River Warnow carried a high load of dissolved organic carbon (14 mg l−1), especially of humic substances (5.5 mg C l−1). Bacterial abundance (12×106 ml−1) as well as production (1.7 μg C l−1 h−1) depended on temperature. During late spring and summer at constantly higher temperatures, bacterial production correlated positively to readily utilisable substrates and to humic compounds. Thus, the bacterial community in River Warnow may be well adapted or contain enough species using the available amino acids and carbohydrates as well as humic matter compounds. However, calculated from protozoan biomass, grazing may control bacterial biomass and perhaps community composition profoundly, what lead to the low percentages of active bacteria.  相似文献   

15.
The flow of carbon and nitrogen in sediments of the far northern and northern sections of the Great Barrier Reef continental shelf was examined. Most of the organic carbon (81–94%) and total nitrogen (74–92%) depositing to the seabed was mineralized, with burial of carbon (6–19%) and nitrogen (8–20%) being proportionally less on this tropical shelf compared with other non-deltaic shelves. Differences in carbon and nitrogen mineralization among stations related best to water depth and proximity to river basins, with rates of mineralization based on net ∑CO2 production ranging from 17 to 39 ( mean=23) mmol C m−2 d−1. The overall ratio of O2:CO2 flux was 1.3, close to the Redfield ratio, implying that most organic matter mineralized was algal. Sulfate reduction was estimated to account for ≈30% (range: 6–62%), and denitrification for ≈5% (range: 2–13%), of total C mineralization; there was no measurable CH4 production. Discrepancies between ∑CO2 production across the sediment–water interface and sediment incubations suggest that as much as 5 mmol m−2 d−1 (≈25% of ∑CO2 flux) was involved in carbonate mineral formation. Most microbial activity was in the upper 20 cm of sediment. Rates of net NH4+ production ranged from 1.6 to 2.7 mmol N m−2 d−1, with highly variable N2 fixation rates contributing little to total N input. Ammonification and nitrification rates were sufficient to support rapid rates of denitrification (range: 0.1–12.4 mmol N m−2 d−1). On average, nearly 50% of total N input to the shelf sediment was denitrified. The average rates of sedimentation, mineralization, and burial of C and N were greater in the northern section of the shelf than in the far northern section, presumably due to higher rainfall and river discharge, as plankton production was similar between regions. The relative proportion of plankton primary production remineralized at the seafloor was in the range of 30–50% which is at the high end of the range found on other shelves. The highly reactive nature of these sediments is attributed to the deposition of high-quality organic material as well as to the shallowness of the shelf, warm temperatures year-round, and a variety of physical disturbances (cyclones, trawling) fostering physicochemical conditions favorable for maintaining rapid rates of microbial metabolism. The rapid and highly efficient recycling of nutrients on the inner and middle shelf may help to explain why the coral reefs on the outer shelf have remained unscathed from increased sediment delivery since European settlement.  相似文献   

16.
The consequences of a coastal upwelling event on physical and chemical patterns were studied in the central Gulf of Finland. Weekly mapping of hydrographical and -chemical fields were carried out across the Gulf between Tallinn and Helsinki in July–August 2006. In each survey, vertical profiles of temperature and salinity were recorded at 27 stations and water samples for chemical analyses (PO43−, NO2−+NO3−) were collected at 14 stations along the transect. An ordinary distribution of hydrophysical and -chemical variables with the seasonal thermocline at the depths of 10–20 m was observed in the beginning of the measurements in July. Nutrient concentrations in the upper mixed layer were below the detection limit and nutriclines were located just below or in the lower part of the thermocline. In the first half of August, a very intense upwelling event occurred near the southern coast of the Gulf when waters with low temperature and high salinity from the intermediate layer surfaced. High nutrient concentrations were measured in the upwelled water – 0.4 μmol l−1 of phosphates and 0.6 μmol l−1 of nitrates+nitrites. We estimated the amount of nutrients transported into the surface layer as 238–290 tons of phosphorus (P)-PO43− and 175–255 tons of N-NOx for a 12 m thick, 20 km wide and 100 km long coastal stretch. Taking into account a characteristic along-shore extension of the upwelling of 200 km, the phosphate-phosphorus amount is approximately equal to the average total monthly riverine load of phosphorus to the Gulf of Finland. It is shown that TS-characteristics of water masses and vertical distribution of nutrients along the study transect experienced drastic changes caused by the upwelling event in the entire studied water column. TS-analysis of profiles obtained before and during the upwelling event suggests that while welled up, the cold intermediate layer water was mixed with the water from the upper mixed layer with a share of 85% and 15%. We suggest that the coastal upwelling events contribute remarkably to the vertical mixing of waters in the Gulf of Finland. Intrusions of nutrient-rich waters along the inclined isopycnal surfaces in the vicinity of upwelling front were revealed. The upwelling event widened the separation of phosphocline and nitracline which in turn prevented surfacing of nitrate+nitrite-nitrogen during the next upwelling event observed a week after the upwelling relaxation. A suggestion is made that such widening of nutricline separation caused by similar upwelling events in early summer could create favourable conditions for late summer cyanobacterial blooms.  相似文献   

17.
The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahía de La Paz, Gulf of California was investigated as part of the ichthyotoxic mechanism of this microalga. Two different kinds of erythrocytes, fish and human, were tested for the hemolytic assay. Since fatty acids have been associated with hemolytic activity in C. polykrikoides, the composition of fatty acids of this dinoflagellate was also analyzed. The concentration of C. polykrikoides causing 50% hemolysis (HE50) was 4.88 and 5.27 × 106 cells L−1, for fish and human erythrocytes, respectively. According to the standard curve of saponin, an equivalence between the hemolytic activity of saponin and the dinoflagellate concentration was found with 1 μg saponin mL−1 equivalent to 1 × 106 cells L−1 of C. polykrikoides. The polyunsaturated fatty acids: hexadecaenoic (16:0), docosahexaenoic (22:6 n3) and octadecapentaenoic (18:5 n3) were found in an abundance of 62% of total fatty acids.  相似文献   

18.
We investigated the response of phytoplankton and zooplankton to experimental alteration of nitrate and phosphate levels in outdoor enclosures. Experiments were conducted in summer and winter and in the absence and presence of a layer of soil. The tubs (12 in all) except the two plain water controls were manured initially with a mixture of fresh cowdung (50g 1−1), mustard oil cake (25 g l−1) and poultry wastes (25 g l−1; mostly excreta), prior to enrichment. Water samples were collected from the experimental tubs twice a week to measure selected physico-chemical and biological variables. Water temperature in the summer experiments ranged from 20–30 °C and during the winter experiments from 11–15 °C. The pH values ranged from 8.0 to 9.5 and the dissolved oxygen levels from 8.2–10.0 mg l−1. The levels of soluble reactive phosphorus and nitrate nitrogen ranged from undetectable levels to 1800 μg l−1 and 6000 μg l−1, respectively. The increase in chlorophyll-a following enrichment was rapid (3–7 days) during summer, but slower in winter (7–14 days). The predominant phytoplankton species observed in the tubs belong to the genera Sphaerocystis, Chlorella, Scenedesmus, Cosmarium, Ulothrix, Zygnema, Gonium and Pandorina. The rotifer species observed were Brachionus calyciflorus, Rotaria neptunia, Lecane bulla, L. luna, L. unguitata, Euchlanis dilatata, Asplanchna intermedia, Pseudoharringia spp., Eosphora spp., Lepadella ovalis, Epiphanes brachionus, Hexarthra mira and Cephalodella gibba. The cladocerans observed were Macrothrix spp. and Alona spp.  相似文献   

19.
Concentrations of 14 different dissolved free amino acids (DFAA), dissolved inorganic nitrogen (DIN), and chlorophyll a were determined in the surface microlayer and subsurface waters at 41 stations in the Yellow Sea, China in April 2006. The concentrations of DFAA in the subsurface water ranged from 0.13 to 1.62 μM, with an average of 0.57±0.05 μM, while those in the surface microlayer varied between 0.22 and 2.6 μM, with an average of 0.94±0.08 μM. Major constituents of DFAA present in the study area were glycine, alanine, glutamic acid, serine and histidine. One-way analysis of variance (ANOVA) showed no significant difference in average mol fractions of DFAA between microlayer and subsurface water (F=0.0440, P=0.8355). Hierarchical cluster analysis of the station similarity based on the DFAA composition in both the surface microlayer and subsurface water separated three clusters of stations at the 70% Bray–Curtis similarity level. The average concentrations of chlorophyll a and DIN were 1.18 (0.34–4.44) μg L−1 and 16.57 (3.98–49.59) μM in the subsurface water, and those in the surface microlayer were 1.30 (0.24–3.97) μg L−1 and 18.56 (5.77–48.93) μM, respectively. Our results showed that concentrations of chlorophyll a (r2=0.7940, n=41, p<0.0001), DIN (r2=0.6939, n=41, p<0.0001) and DFAA (r2=0.2416, n=41, P=0.0011) in the microlayer were, respectively, correlated with their subsurface water concentrations, implying that there was a strong exchange effect between the microlayer and subsurface water. The enrichment factor of DFAA in the microlayer ranged from 0.47 to 2.24 with a mean of 1.88±0.16.  相似文献   

20.
Dietary intake is one of the important routes of human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). The use of PBDEs may also result in exposure to polybrominated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs), as these compounds are impurities in technical mixtures of BFRs and can also be formed unintentionally by the same processes that generate chlorinated dioxins. This study determined the concentrations of polybrominated compounds in common seafood in Guangzhou and Zhoushan, and assessed the health risks of these chemicals via consumption of contaminated seafood. Seafood samples (fish, bivalves, shrimp, crab, and cephalopods) purchased from local markets in 2003 and 2004 were analyzed for PBDEs and PBDDs/DFs. The highest concentration of total PBDEs (46.3 ng g−1 lipid wt.) was detected in fish from Guangzhou, in which BDEs 47 and 209 were the two predominant congeners. The total daily intakes of PBDEs, PBDDs, and PBDFs were, 946, 6.39, and 6.54 pg kg−1 body weight (bw) in Guangzhou, and 489, 4.99, and 7.65 pg kg−1 bw in Zhoushan, respectively. The hazard ratios for PBDDs and PBDFs were both greater than unity, indicating that these compounds may pose some health risks to the local population.  相似文献   

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