首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
Copper, Zn, and Cd were analyzed in the soft tissues of the edible gastropod Hexaplex trunculus collected from seven localities along the Tunisian coast. The body concentration of these metals was significantly different depending on the gender and site. Copper and Zn varied, respectively, from 47.70 to 343.64 μg/g dry weight (dw) and 149.46 to 530.44 μg/g dw, being higher in males. Cadmium varied from 0.22 to 18.95 μg/g dw and was always higher in females. Overall, the highest concentrations of the three metals were all recorded in Gabès fishing harbor. Comparison of metal concentrations with the European standards compiled by the Food and Agriculture Organization showed that values exceeded standards in several localities. Imposex had been previously recorded in H. trunculus along the Tunisian coast; however, it does not seem to be related with Cu, Zn, and Cd pollution because the body concentration of these metals is not correlated with imposex degree. Nevertheless, interactive effects resulting from the combination of different pollutants and other stressors cannot be disregarded.  相似文献   

2.
In this paper, the concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in biota (reed, grass, mussel, fish, and red-crowned crane) and sediments collected from seven locations in the Zha Long Wetland. PAHs were recovered from the sediments and biota by ultrasonic extraction and then analyzed by means of gas chromatography-mass spectrometry. The total PAH concentrations were 244–713 ng/g dw in sediments, 82.8–415 ng/g dw in plants and 207–4,780 ng/g dw in animals. The total sediment PAH concentrations were categorized as lower to moderate contamination compared with other regions of China and the world. In the plant samples, the accumulation abilities of reed roots and stems for PAHs were higher than those of grass roots. In addition, the concentration of individual PAHs in mussel muscles was the highest in all of the animal samples, followed by fish, feeding crane fetuses, and wild crane fetuses. Compositional analysis suggests that the PAHs in the sediments from the Zha Long Wetland were derived from incomplete biomass combustion. Risk assessment shows that the levels of PAHs in sediments are mostly lower than the effects range mean value (effects range mean), whereas only naphthalene in all sample sites was higher than the effects range low value. It is worthwhile to note that benzo(b)fluoranthene, benzo(k)fluoranthene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were detected in crane fetal, which have potential carcinogenicity for organisms from the Zha Long Wetland.  相似文献   

3.
Some wetland plant species are adapted to growing in the areas of higher metal concentrations. Use of such vegetation in remediation of soil and water contaminated with heavy metals is a promising cost-effective alternative to the more established treatment methods. Throughout the year, composite industrial effluents bringing various kinds of heavy metals contaminate our study site, the East Calcutta Wetlands, a Ramsar site at the eastern fringe of Kolkata city (formerly Calcutta), India. In the present study, possible measures for remediation of contaminated soil and water (with elements namely, Ca, Cr, Cu, Pb, Zn, Mn, and Fe) of the ecosystem had been investigated. Ten common regional wetland plant species were selected to study their efficiency and diversity in metal uptake and accumulation. Results showed that Bermuda grass (Cynodon dactylon) had the highest total Cr concentration (6,601 ± 33 mg kg???1 dw). The extent of accumulation of various elements in ten common wetland plants of the study sites was: Pb (4.4?C57 mg kg???1 dw), Cu (6.2?C39 mg kg???1 dw), Zn (59?C364 mg kg???1 dw), Mn (87?C376 mg kg???1 dw), Fe (188?C8,625 mg kg???1 dw), Ca (969?C3,756 mg kg???1 dw), and Cr (27?C660 mg kg???1 dw) indicating an uptake gradient of elements by plants as Ca>Fe>Mn>Cr>Zn>Cu>Pb. The present study indicates the importance of identification and efficiency of metal uptake and accumulation capabilities by plants in relation to their applications in remediation of a contaminated East Calcutta Wetland ecosystem.  相似文献   

4.
Seawater may be contaminated by harmful substances, including toxic elements released by human activities. The present study evaluates the total mercury and methylmercury concentrations and their correlations to fish body size in longtail tuna and short-bodied mackerel from Chendring, Kuantan, at east coast and Kuala Perlis at west costs of Peninsular Malaysia during May to November 2007. Total mercury and methylmercury in muscle tissue of 69 samples of longtail tuna and short-bodied mackerel, ranged from 0.180 to 1.460 μg/g and 0.0.169–0.973 μg/g and 0.251–1.470 μg/g and 0.202–1.352, whereas the methylmercury to total mercury ratio ranged from 70% to 83%, respectively. Samples of both species from the east coast showed higher levels of mercury compared to those from west coast. In all of the locations, significant positive correlations were found between fish body weight and mercury content (R2?> 0.470). The estimated weekly intake of total mercury and methylmercury from the consumption 66.33 g/week of short-bodied mackerel and 18.34 g/week of longtail tuna (based on local dietry survey) was found to be lower than the maximum limit of 5 and 1.5 μg/kg bodyweight established by FAO/WHO and codex, respectively.  相似文献   

5.
Cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) were analyzed in the breast feather of white-fronted geese (Anser albifrons, n?=?15), mallards (Anas platyrhynchos, n?=?4), and spot-billed ducks (Anas poecilorhyncha, n?=?13) found dead in Gimpo, Korea. All of the mallards and eight of the 13 spot-billed ducks had embedded shot. Concentrations of Pb, Cr, Cu, Mn, Zn, and Fe were significantly different among waterfowl species. Mallards with embedded shot had relatively higher Pb, Cr, Mn, and Fe concentrations than the other species. Cd and Cr in feathers of waterfowl species were within the range reported for other birds, and no specimen exceeded the tentative threshold effect levels of Cd (2 μg/g dry weight (dw)) and Cr (2.8 μg/g dw) for birds. However, Pb in feathers of all four mallards and two spot-billed ducks exceeded the threshold for deleterious effects (>4 μg/g dw). Essential elements such as Cu, Mn, Zn, and Fe in the feather of waterfowl species were not at toxic levels and within the background or normal range for the homeostatic mechanisms.  相似文献   

6.
Sediments of the Elbe River have been extremely polluted by contaminants originating from previous large-scale hexachlorocyclohexane (HCH) production and the application of γ-HCH (lindane) in its catchment in the second half of the twentieth century. In order to gain knowledge on bioaccumulation processes at lower trophic levels, field investigations of HCHs in macroinvertebrates were carried out along the longitudinal profile of the Elbe and tributary. Among the sites studied, concentrations in macroinvertebrates ranged within five orders of magnitude (0.01–100 μg/kg). In general, lower values of HCH isomers were observed at all Czech sites (mostly <1 μg/kg) compared with those in Germany. At the most contaminated site, Spittelwasser brook (a tributary of the Mulde), extremely high concentrations were measured (up to 234 μg/kg α-HCH and 587 μg/kg β-HCH in Hydropsychidae). In contrast, the Ob?íství site, though also influenced by HCH production facilities, showed only negligibly elevated values (mostly <1 μg/kg). Results showed that fairly high levels of α-HCH and β-HCH compared to γ-HCH can still be detected in aquatic environments of the Elbe catchment, and these concentrations are decreasing over time to a lesser extent than γ-HCH. Higher HCH concentrations in sediments in the springtime are considered to be the result of erosion and transport processes during and after spring floods, and lower concentrations at sites downstream are thought to be caused by the time lapse involved in the transportation of contaminated particles from upstream. In addition, comparison with fish (bream) data from the literature revealed no increase in tissue concentrations between invertebrates and fish.  相似文献   

7.
Concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in 28 surface soils samples collected from Urumqi, northwest China, for examination of distributions, source contributions, and potential health effects. The results indicated that the sum of 16 PAHs concentration ranged from 331 to 15,799 μg?kg?1 (dw) in soils, with a mean of 5,018?±?4,896 μg?kg?1 (n?=?28). The sum of seven carPAHs concentration ranged from 4 to 1,879 μg?kg?1 (dw; n?=?28). The highest ∑PAHs concentrations were found at roadsides and industrial sites, followed by those at parks, rural areas, and business/residential areas. Coal combustion, emission of diesel and gasoline from vehicles, and petroleum source were four sources of PAHs as determined by PMF analysis, which contributed 51.19, 19.02, 18.35, and 11.42 % to the PAH sources, respectively. Excellent coefficients of correlation between the measured and predicted PAHs concentrations suggested that the PMF model was very effective to estimate sources of PAHs in soils. Incremental lifetime cancer risk values at the 95th percentile due to human exposure to surface soils PAHs in Urumqi were 2.02?×?10?6 for children and 2.72?×?10?5 for adults. The results suggested that the current PAHs levels in soils from Urumqi were pervasive and moderately carcinogenic to children and adults.  相似文献   

8.
The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53–128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21–610.45 ng/g dw at the Du Toit sampling site and 30.86–444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53–397.75 ng/g dw at the Msunduzi Town sampling site and 20.84–443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68–22.37 and 2.53–35.69 ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.  相似文献   

9.
In this study, we examined the bioavailability of arsenic through the mangrove oyster Crassostrea corteziensis sampled from seven coastal lagoons in SE Gulf of California during the rainy and dry seasons. As concentrations in soft tissue of oysters C. corteziensis fluctuated between 5.2 and 11.6 μg/g on dry weight; organisms from the control site presented the lowest As concentrations in the two sampling seasons. As speciation was evaluated in selected samples and indicated that arsenobetaine was the major arseno-compound accounting for 53.5–74.7 % of total As. Lower percentage contributions were obtained for nonextractable As (9.7–25.5 %) and other molecules such as arsenocholine and methyl-arsonate (<5 %). Inorganic As was detectable in only two samples, at concentrations lower than 0.1 μg/g. These As data are the first generated in NW Mexico and indicate that C. corteziensis is safe for human consumption in terms of arseno-compounds. It is evident that As bioavailability in these lagoons is low.  相似文献   

10.
Studies on the use of tree bark as biomonitors for environmental pollutants are still very scarce. We evaluated the reliability of using Jacaranda mimosifolia, a common tree in Tshwane City of South Africa, as a suitable biomonitor of atmospheric trace metals. Bark samples were collected from ten different locations during two sampling periods. The concentrations of the metals were determined by inductively coupled plasma mass spectrometry. The concentrations of the metals were 33.2–1,795 μg/g (Pb), 21.4–210 μg/g (Cu), 68.4–490 μg/g (Zn), 30.6–2,916 μg/g (Cr), 0.12–1.34 μg/g (Cd), and 6.04–68.0 μg/g (V), respectively. The differences obtained for the results from different sites were significant (p?< 0.05). A significant difference was also observed between the two sampling periods. The trace metals concentrations suggested that automobile emissions are a major source of these metals. The study also confirms the suitability of J. mimosifolia as a biomonitor of atmospheric deposition of these metals.  相似文献   

11.
Several agricultural fields show high contents of arsenic because of irrigation with arsenic-contaminated groundwater. Vegetables accumulate arsenic in their edible parts when grown in contaminated soils. Polluted vegetables are one of the main sources of arsenic in the food chain, especially for people living in rural arsenic endemic villages of India and Bangladesh. The aim of this study was to assess the feasibility of floriculture in the crop rotation system of arsenic endemic areas of the Bengal Delta. The effects of different arsenic concentrations (0, 0.5, 1.0, and 2.0 mg As L?1) and types of flowering plant (Gomphrena globosa and Zinnia elegans) on plant growth and arsenic accumulation were studied under hydroponic conditions. Total arsenic was quantified using atomic absorption spectrometer with hydride generation (HG-AAS). Arsenic was mainly accumulated in the roots (72 %), followed by leaves (12 %), stems (10 %), and flowers (<1 %). The flowering plants studied did not show as high phytoremediation capacities as other wild species, such as ferns. However, they behaved as arsenic tolerant plants and grew and bloomed well, without showing any phytotoxic signs. This study proves that floriculture could be included within the crop rotation system in arsenic-contaminated agricultural soils, in order to improve food safety and also food security by increasing farmer’s revenue.  相似文献   

12.
The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and organochlorine pesticides (OCPs) in surface sediments from the lower reaches of the Haihe River basin, northern China, were determined by high-resolution gas chromatograph–high-resolution mass spectrometer. The concentrations of 2,3,7,8-substituted PCDD/Fs, dl-PCBs, and total OCPs [sum of hexachlorobenzene, hexachlorocyclohexanes, and dichlorodiphenyltrichloroethane (DDTs)] in 17 sediment samples were in the ranges of 11.6–1,180,924 pg/g dry weight (dw), 18.7–50,017 pg/g dw, and 1.7–35,280 ng/g dw, respectively. The contamination levels in the samples varied significantly between the different sites. Abnormally high concentrations of PCDD/Fs, dl-PCBs, and some OCPs were found in sediments from the lower reaches of the main channel of the Haihe River and the Dagu Drainage River, which were attributed to the historical production of pentachlorophenol and other pesticides near these locations. High levels of DDTs were detected in the Yongding New River sediment, which were likely to have originated from the discharge of wastewater from a dicofol factory upstream. In samples taken from other sites, the concentrations of these pollutants were at levels comparable to those documented in other areas of China. This preliminary investigation suggests that historical pesticide production in the Haihe River basin has contributed significantly to the contamination of this aquatic ecosystem and that further attention to this issue is warranted.  相似文献   

13.
The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in Gomti River, a major tributary of the Ganga river (India). A total of 96 samples (water and sediments) were collected from eight different sites over a period of 2 years and analysed for 16 PAHs. The total concentrations of 16 PAHs in water and bed sediments ranged between 0.06 and 84.21 ??g/L (average (n?=?48), 10.33 ± 19.94 ??g/L) and 5.24?C3,722.87 ng/g dw [average (n?=?48): 697.25 ± 1,005.23 ng/g dw], respectively. In water, two- and three-ring PAHs and, in sediments, the three- and four-ring PAHs were the dominant species. The ratios of anthracene (An)/An + phenenthrene and fluoranthene (Fla)/Fla + pyrene were calculated to evaluate the possible sources of PAHs. These ratios reflected a pattern of pyrolytic input as a major source of PAHs in the river. Principal component analysis, further, separated the PAHs sources in the river sediments, suggesting that both the pyrolytic and petrogenic sources are contributing to the PAHs burden. The threat to biota of the river due to PAHs contamination was assessed using effect range low and effect range median values, and the results suggested that sediment at some occasions may pose biological impairment.  相似文献   

14.
The management of protected areas in karstic regions is a challenge because flooded cave systems form there and provide underground hydrological conducts that may link different zones. As a consequence, affectations to the protected areas can possibly occur as a consequence of human activities in remote areas and may therefore pass undetected. Thus, the monitoring of possible contaminants in these regions is becoming imperative. In this work, we analyze the concentration of essential (iron) and non-essential metals (cadmium and chromium) in the seagrass Thalassia testudinum that grows in Yalahau Lagoon, located in a near-to-pristine protected area of the Yucatán Peninsula, close to the rapidly developing touristic belt of the Mexican Caribbean. Salinity and silicate patterns show that Yalahau is an evaporation lagoon, where groundwater discharge is important. High iron (>400 μg/g), cadmium (>4 μg/g), and chromium (≈1 μg/g) concentrations were found in the area of highest groundwater input of the lagoon. High levels (5.1 μg/g) were also found near the town dump. In the rest of the sampling sites, metal concentrations remained near to background levels as estimated from other works. Temporal changes of concentrations in the seagrass tissues show also a local input and an input from the groundwater that could provoke an environmental problem in the Yalahau Lagoon in the near future.  相似文献   

15.
Annual trends of a group of 66 volatile organic compounds (VOCs), containing 20 ozone precursors, were the aim of a sampling campaign carried out for a year in air at urban and industrial areas from Tarragona region. VOCs were determined by active collection on multisorbent tubes, followed by thermal desorption and gas chromatography–mass spectrometry. The analytical method was developed and validated, showing good levels of detection and quantification, recoveries, precision, and linearity for all the compounds in the range being studied. All the industrial and urban samples taken during the sampling campaign were similar in their qualitative composition. The most abundant compound in all urban and industrial sites was i-pentane, with concentrations between 15.2 and 202.1 μg m???3 in urban sites and between 1.3 and 98.6 μg m???3 in industrial sites. In urban sites, the following compounds in order of abundance were toluene, n-pentane, m,p-xylene, and o-xylene, with maximum levels of 150.6, 45.8, 42.3, and 31.7 μg m???3, respectively. In industrial sites, the most abundant compounds depended on the sampled site.  相似文献   

16.
This study reports the level of total petroleum hydrocarbons (TPH) and trace heavy metals (lead, copper, and cadmium) in soil samples collected randomly from Iyana–Iba garage, Lagos State University bus stop, Adeniran Ogunsanya College of Education bus stop, and a control site off Lusada–Atan road, near Crawford University, Igbesa, Ogun state. TPH was estimated gravimetrically after Soxhlet extraction and column clean up, while soil metals were determined by atomic absorption spectrometry using mineral acid digestion. For TPH, the sites have mean values of 19.43 ± 1.27, 16.11 ± 1.85, and 11.43 ± 4.33 mg/g with a control mean value of 0.33 ± 0.16 mg/g. For trace heavy metals, cadmium was not detected. However, the mean levels of lead are 4.24 ± 3.10, 3.72 ± 0.60, and 3.70 ± 1.32 μg/g, respectively, whereas mean copper concentrations are 20.63 ± 9.02, 19.35 ± 3.61, and 16.76 ± 3.02 μg/g in all sites, respectively, compared to the control mean of 0.25 ± 0.13 and 5.99 ± 1.23 μg/g for lead and copper, respectively. Sites studied have higher levels of TPH and metals compared to the control soil samples. This is indicated by a statistically significant difference found between the concentration of analyzed elements in soils collected along Lagos–Badagry expressway and the control site.  相似文献   

17.
Polybrominated diphenyl ethers (PBDEs) were measured in soil and three plant species samples taken at different land use areas in Shenzhen China. The concentrations of ??7BDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) and BDE-209 in the surface soils ranged from 0.23 to 271 and 8.9 to 5,956 ng/g dry weight (dw), respectively. These figures are comparable to that in the soils of electronic waste dismantling sites. BDE-209 was the predominant congener (contributes 85?C99% of ??8PBDEs (??7PBDEs plus BDE-209)) in soils. The regression slopes of total organic carbon and individual BDE congeners were rather gentle, indicating that factors other than soil organic matter regulated the soil concentrations. Proximity to sources of deposition processes might be the major factors. In the plant leaves, ??7BDEs and BDE-209 concentrations ranged from 1.29 to 5.91 and 5.49 to 28.2 ng/g dw, respectively. BDE-209 is also the dominant component, but the contribution was much lower compared with that in soils. Bauhinia purpurea Linn. and Michelia alba DC. show some similarities on the uptake of PBDEs, while Ficus microcarpa var. pusillifolia is different from them. The correlations between plant leaf concentrations and predicted gaseous concentrations were moderate, indicating that gaseous concentration did not influence the leaf concentration significantly.  相似文献   

18.
Mae Moh is a risky area for arsenic contamination caused by the effluent from biowetland ponds in Mae Moh lignite-fuelled power plant. The objective of this study was to investigate the arsenic concentrations of Mae Moh biowetland ponds and determine the main factors which are important for arsenic phytoremediation in the treatment system. The result revealed that arsenic concentrations in the supernant were in the range of less than 1.0 μg As L???1 to 2.0 μg As L???1 while those in the sediment were in the range of 25–200 μg As kg soil???1. Both values were below the Thailand national standard of 0.25 mg As L???1 for water and 27 mg As kg soil???1 for the soil. Arsenic accumulation in the biomass of 5 aquatic plants at the biowetland ponds ranged from 123.83 to 280.53 mg As kgPlant???1. Regarding the result of regression analysis (R 2?= 0.474 to 0.954), high concentrations of organic matter and other soluble ions as well as high pH value in the sediment could significantly enhance the removal of soluble arsenic in the wetland ponds. From the regression equation of accumulated arsenic concentration in each aquatic plant, Eichhornia crassipes (Mart.) Solms. (R 2?= 0.954), Ipomoea aquatica Forsk. (R 2?= 0.850), and Typha angustifolia (L.) (R 2?= 0.841) were found to be preferable arsenic removers for wastewater treatment pond in the condition of low Eh value and high content of solid phase EC and phosphorus. On the other hand, Canna glauca (L.) (R 2?= 0.749) appeared to be favorable arsenic accumulator for the treatment pond in the condition of high Eh value and high concentration of soluble EC.  相似文献   

19.
We analyzed national data on blood lead levels (BLL) and blood cadmium levels (BCL) in residents living near 38 abandoned metal mining areas (n?=?5,682, 18–96 years old) in Korea that were collected by the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM) from 2008 to 2011. The geometric mean BCL and BLL were 1.60 μg/L (95 % CI?=?1.57–1.62 μg/L) and 2.87 μg/dL (95 % CI?=?2.84–2.90 μg/dL), respectively, notably higher than levels in the general population in Korea and other countries. We found significantly higher BLL and BCL levels in people living within 2 km of an abandoned metal mine (n?=?3,165, BCL?=?1.87 μg/L, BLL?=?2.91 μg/dL) compared to people living more than 2 km away (n?=?2,517, BCL?=?1.31 μg/L, BLL?=?2.82 μg/dL; P?<?0.0001) and to the general population values reported in the literature.  相似文献   

20.
Blue mussels (Mytilus edulis) and sediments collected from 1991 to 2005 from New Bedford Harbor (NBH), MA, were analyzed for two polycyclic musks (HHCB or Galaxolide® and AHTN or Tonalide®), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). HHCB and AHTN were found in mussel tissues at mean concentrations of 836 and 376 ng/g lipid weight (lw), respectively, which were two- to seven-fold higher than those found at a reference site. Mean concentrations of HHCB and AHTN in NBH sediments were 12 and 6.3 ng/g dry weight (dw), respectively. Four- and five-ringed PAHs, such as phenanthrene, anthracene, fluoranthene, and pyrene, collectively accounted for 61 % of the ∑PAHs concentrations in mussels from NBH. Mean ΣPCB concentrations in mussels from upper and lower NBH were 942 and 182 μg/g lw, respectively, and were dominated by tetra- and penta-chlorobiphenyl congeners, collectively accounting for 61 % of the ΣPCB concentrations. The mean concentration of ∑PBDEs in mussels from NBH was 277 ng/g lw, and no significant difference existed in the concentrations between upper and lower NBH. DDTs were the major OCP found in mussels, found at a mean concentration of 778 ng/g lw. The concentrations of HHCB, AHTN, ΣPBDEs, ΣPAHs, and DDTs in mussels decreased significantly (r 2?≥?0.56, p?≤?0.052) from 1991 to 2005. The concentrations of PCBs and chlordanes did not exhibit a decreasing trend in mussel tissues (r 2?<?0.50; p?>?0.076) from 1991 to 2005. Based on the temporal trends in the concentrations of HHCB, AHTN, ∑PAHs, and ∑PBDEs found in mussels from NBH, it was estimated that between 5.5 and 12 years were required for the concentrations of these compounds to decrease by half (i.e., environmental halving time) of the levels found in 1991.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号