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1.
The low Ebro River basin (NE Spain) represents a particular case of chronic and long-term mercury pollution due to the presence of an industrial waste (up to 436 μg/g of Hg) coming from a chlor-alkali plant Albeit high total mercury (THg) levels have been previously described in several aquatic species from the surveyed area, methylmercury (MeHg) values in fish individuals have never been reported. Accordingly, in order to investigate bioaccumulation patterns at different levels of the aquatic food web of such polluted area, crayfish and various fish species, were analysed for THg and MeHg content. At the hot spot, THg mean values of crayfish muscle tissue and hepatopancreas were 10 and 15 times, respectively, greater than the local background level. Higher mean THg concentrations were detected in piscivorous (THg=0.848 ± 0.476 μg/g wet weight (ww); MeHg=0.672 ± 0.364 μg/g ww) than in non-piscivorous fish (THg=0.305 ± 0.163 μg/g ww; MeHg=0.278 ± 0.239 μg/g ww). Although these results indicated that THg in fish increased significantly with increasing trophic position, the percentage of the methylated form of Hg was not strongly influenced by differences in relative trophic position. This is an important finding, since the fraction of THg as MeHg in the top fish predator was unexpectedly lower than for other species of the aquatic food chain. Moreover, mean THg concentrations in piscivorous fish exceed the maximum level recommended for human consumption. From our findings, it is clear that for this specific polluted system, speciation becomes almost mandatory when risk assessment is based on MeHg, since single measurements of THg are inadequate and could lead to an over- or under-estimation of contamination levels.  相似文献   

2.
Mercury levels in hair of a general population, 237 adults aged between 35-45, in Naples, Italy, were assessed. The subjects were asked to fill in a questionnaire about age, gender, body weight, height, body mass index (BMI), fish consumption, number, surface and area of dental amalgam fillings. Total mercury (THg) concentrations in human hair ranged from 0.221 to 3.402 microg/g and the mean value for the subjects under study was 0.638 microg/g. Study participants were divided into three groups in accordance with fish consumption and dental amalgam: ANF (amalgam and no fish); NAF (no amalgam but with fish) and AAF (amalgam and fish). Significant differences in THg were found in the three groups (p<0.05). A multiple linear regression analysis showed a weak but significant correlation of THg content in hair with respect to gender and age, but almost no association was found between THg and dental fillings. Conversely, a strong correlation was obtained between THg and fish consumption regardless of the group evaluated. Finally, mercury levels in hair exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 microg Hg/kg body weight per day (1 microg Hg/g hair) in 6% of the population (4% men and 2% women). However, the THg limits in our subjects were not exceeded according to the WHO guidelines, which use a benchmark dose of 0.23 microg Hg/kg bw/day (14 microg Hg/g maternal hair).  相似文献   

3.
Measurements of ambient radiation doses and determination of radionuclide concentrations in mining waste and soils were performed in 60 areas of former radium and uranium mining. In several places, mining waste and low-grade uranium ore left on the surface contain radioactivity above regional background. Most of the former mining sites present no enhanced radionuclide concentrations. However, in the mining facilities where the radioactive ore was chemically extracted, mill tailings contain materials with elevated levels of radioactivity, up to 200 times the levels in unaffected soils of the region. Mud from neutralization ponds used to treat acid mine waters contains also elevated radionuclide concentrations. Furthermore, depending on the type of waste, the radioelement composition varies. Environmental rehabilitation measures shall take these differences into account in order to prevent in the long term the radioactive contamination of agriculture soils and water resources, and to ensure adequate radiological protection to the public and to the environment.  相似文献   

4.
Total mercury concentrations were determined by cold-vapour atomic absorption spectroscopy (CV-AAS) in 117 samples of caps, 117 of stalks and 47 of whole fruiting bodies of 13 species of wild mushrooms and in 164 underlying soil substrate collected from Zaborski Landscape Park during 1997 and 1998. The study area is a background, forested site with rural landscape and no known local sources of mercury emission. Mean mercury concentrations in mushrooms varied widely (range: 50 +/- 20 to 3700 +/- 1700 ng/g, dry matter) depending on the site and mushroom species investigated. However, mercury concentrations in soil samples varied less (range: 3.0 +/- 3.0 to 43 +/- 17 ng/g dry matter). Fruiting bodies of Common Puffball (Lycoperdon perlatum) and King Bolete (Boletus edulis) contained the greatest concentrations of mercury of 3700 +/- 1700 and 2600 +/- 1200 ng/g dry matter, respectively. A positive correlation existed between mercury concentrations in the caps of Slippery Jack (Suillus luteus) and Fly Agaric (Amanita muscaria) (p < 0.01) and mercury concentrations in corresponding soils. However, concentrations of mercury in The Sickener (Russula emetica) was negatively correlated with its soil substrate (p < 0.01). Bioconcentration factors (BCFs: concentrations ratios of mercury in mushroom to soil) of total mercury in whole fruiting bodies or caps were greatest for Common Puffball (L. perlatum), Larch Bolete (Suillus grevillei) and King Bolete (B. edulis) and varied between 130 +/- 78 and 160 +/- 120, while for the other species BCFs were between 4.0 +/- 6.0 and 61 +/- 20 in caps, and 4.4 +/- 3.1 and 70 +/- 68 in stalks. The concentration ratios of Hg in cap to stalk were from 1.1 +/- 0.5 for Poison Pax (Paxillus involutus) to 2.7 +/- 1.7 in Larch Bolete (S. grevillei).  相似文献   

5.
Mercury mining was a large and thriving industry during the last century in Asturias (NW Spain). At Bra?alamosa, mining activity introduced significant quantities of wastes in spoil heaps located close to the mining operations. In these mining wastes, in addition to mercury, high concentrations of other potentially dangerous elements like As have been found. As a consequence, pollution and dereliction of the local environment occurred. This paper focuses on the environmental impact of these old mining operations and describes a preliminary assessment of the extent of contamination. This includes analytical data from systematic sampling of soils, stream sediments, wastes from spoil heaps, water and herbaceous plants in areas affected by mining activities. The potential risk that spoil materials imply for human health and the environment is documented on the basis of the application of EPA Risk Assessment methodology.  相似文献   

6.
采集了湘潭锰矿红旗分矿开采区、沙圹村恢复区的代表性当季蔬菜(莴笋叶Fruticicolidae、小白菜Brassica chinensis、香葱Allium schoenoprasum、空心菜Ipomoea aquatica)、废弃区的优势植物(商陆Phytolacca acinosa、野茼蒿Crassocephalum crepidioides、苍耳Xanthium sibiricum)和3个研究区的土壤,通过原子吸收分光光度法分析了Mn、Pb、Zn含量。结果表明:开采区蔬菜Mn含量(8.3~84.5 mg/kg)明显高于恢复区(2.7~55.6 mg/kg),开采区和恢复区蔬菜都明显受到Pb污染(0.6~33mg/kg),蔬菜Zn含量范围为1.9~6.5mg/kg;3个研究区域土壤重金属均明显超标,最严重的是Pb污染(1 993.5~2 213.5mg/kg)。商陆、野茼蒿和苍耳中重金属含量差异较大,对重金属的耐性强,其中商陆表现出最好的耐性与长势。研究结论对锰矿土地合理利用以及矿区土壤重金属治理提供一定的科学依据。  相似文献   

7.
Although the transfer of organo-metallic mercury (OrgHg) in aquatic food webs has long been studied, it has only been recently recognized that there is also accumulation in terrestrial systems. There is still however little information about the exposure of grazing animals to OrgHg from soils and feed as well as on risks of exposure to animal and humans.In this study we collected 78 soil samples and 40 plant samples (Lolium perenne and Brassica juncea) from agricultural fields near a contaminated industrial area and evaluated the soil-to-plant transfer of Hg as well as subsequent trophic transfer. Inorganic Hg (IHg) concentrations ranged from 0.080 to 210 mg kg 1 d.w. in soils, from 0.010 to 84 mg kg 1 d.w. in roots and from 0.020 to 6.9 mg kg 1 d.w. in shoots. OrgHg concentrations in soils varied between 0.20 and 130 μg kg 1 d.w. representing on average 0.13% of the total Hg (THg). In root and shoot samples OrgHg comprised on average 0.58% (roots) and 0.66% (shoots) of THg. Average bioaccumulation factors (BAFs) for OrgHg in relation to soil concentrations were 3.3 (for roots) and 1.5 (for shoots).The daily intake (DI) of THg in 33 sampling sites exceeded the acceptable daily intake (ADI) of THg of both cows (ADI = 1.4 mg d 1) and sheep (ADI = 0.28 mg d 1), in view of food safety associated with THg in animal kidneys. Estimated DI of OrgHg for grazing animals were up to 220 μg d 1 (for cows) and up to 33 μg d 1 (for sheep).This study suggested that solely monitoring the levels of THg in soils and feed may not allow to adequately taking into account accumulation of OrgHg in feed crops and properly address risks associated with OrgHg exposure for animals and humans. Hence, the inclusion of limits for OrgHg in feed quality and food safety legislation is advised.  相似文献   

8.
Twenty-one sediment samples in 11 sites along the Haihe River and Dagu Drainage River, Tianjin, China, were analyzed to investigate the pollution status and bioavailability of mercury (Hg). The results showed that the Haihe River was slightly polluted with Hg when flowing through Tianjin city. On the contrary, the sediments collected from Dagu Drainage River, an important drainage river in Tianjin, were found to have very high Hg concentrations and the highest concentration reached 8779.1 ng g(-1) (dry weight). The methylmercury (MeHg) concentrations accounted for 0.1-2.4% (average: 0.9%) of total mercury (HgT) and were strongly influenced by HgT (r=0.91, p=0.99, n=20) and total organic carbon (TOC; r=0.76, p=0.99, n=20) contents in sediments. Moreover, a five-step sequential selective extraction (SSE) procedure was used to study the bioavailability of Hg in sediments. The mercury in sediments existed mainly as element Hg and mercury sulfide, which accounted for 46.5% and 39.0% of HgT, respectively. The percentage of exchangeable Hg (defined as water soluble Hg plus 'human stomach acid' soluble Hg) was only 0.1-4.6%. The distribution of exchangeable Hg showed an obvious difference to that of HgT, indicating that the HgT concentrations were absolutely insufficient to evaluate the risk of Hg in sediments.  相似文献   

9.
Reuse of mining wastewater in agricultural activities in Jordan   总被引:1,自引:0,他引:1  
A pilot study was completed in the Al-Abyad area near phosphate mining activity in Jordan. Six plots of 50 m2 each were planted with two types of plant species (Zea mays spp. and Medicago lupulina spp.) and irrigated using three types of water (fresh groundwater, mine wastewater, and hydride water consisting of 50% fresh and 50% mine wastewater) to investigate the suitability of utilizing mine wastewater for food production in the area. Water, soil and plant sampling was completed for each plot over different time intervals and analyzed for heavy metal (Cr+6, Ni+2, Zn+2 and Pb+2) in addition to major ionic composition of the water used for irrigation. Crop yield was estimated at the end of the experiment. Plots irrigated with mine wastewater showed slightly higher heavy metals concentrations and soil salinity during the experiment period was higher for plots irrigated with mine wastewater compared to plots irrigated with fresh water, and it was uniform through the upper 45 cm of the soil profile due to the high amount of irrigation water used during the experiment. Crop yield was inversely proportional to salinity as an increase of salinity by 2-folds resulted in reducing yield by almost 50%. However, no risk of heavy metals contamination was found in plants and soil. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

10.
Environmental mercury contamination in China: sources and impacts   总被引:16,自引:0,他引:16  
This review article focused on the current status of mercury (Hg) contamination in different ecological compartments in China, and their possible environmental and health impacts, focusing on some major cities. Mercury emission from non-ferrous metals smelting (especially zinc smelting), coal combustion and miscellaneous activities (of which battery and fluorescent lamp production and cement production are the largest), contributed about 45%, 38% and 17%, respectively, to the total Hg emission based on the data of 1999. Mercury contamination is widespread in different ecological compartments such as atmosphere, soil and water. There is evidence showing bioaccumulation and biomagnification of Hg in aquatic food chains, with higher concentrations detected in carnivorous fish. In terms of human exposure to Hg, fish consumption is the major exposure pathway for residents living in coastal cities such as Hong Kong, but inhalation may be another major source, affecting human health in areas with severe atmospheric Hg, such as Guiyang City (Guizhou Province). The first case study indicated that after closure of the acetic acid plant 20 years at Songyuan City (Jilin Province), 16.7% of residents' hair still contained Hg concentration in excess of 1 mg/kg (the reference dosage value, RfD set by USEPA). The second case study indicated that the male residents of Hong Kong who consumed more than four or more meals of fish per week tended to contain higher Hg in their hair, which was linked to their subfertility. There is also increasing evidence showing that skin disorders and autism in Hong Kong children are related to their high Hg body loadings (hair, blood and urine), through prenatal methyl Hg exposure. There seems to be an urgent need to identify the sources of Hg, speciation and concentrations in different ecological compartments, which may lead to high body loadings in human beings. Adverse health effects of residents living in places with a higher background level of Hg, due to long-term exposure to chronic levels of Hg through oral intake should not be overlooked.  相似文献   

11.
Metal contamination of farming soils affected by industry   总被引:50,自引:0,他引:50  
The contents of nine elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb and Zn) have been assayed in the farming soils of Suszec commune (southern Poland). This area is affected by the main industrial centre of Poland (the Upper Silesian Industrial Region), the Czech Republic (Trzyniec smelter) and local contamination sources (coal mine). The contamination of the soils was assessed on the basis of geoaccumulation index, enrichment factor, contamination factor and degree of contamination. The tests revealed elevated contents of cadmium, lead, arsenic, antimony and mercury. The contents of the other elements were similar to the levels in the Earth's crust or pointed to metal depletion in the soil (EF<1).  相似文献   

12.

Mining has become one of the main causes of increased heavy metal loading of river systems throughout the world. There is however an evident gap between assessments of soil contamination and metal release at the mined sites and estimates of river pollution. The present work focuses on Zaamar Goldfield, which is one of the largest placer gold mines in the world, located along the Tuul River, Mongolia, which ultimately drains into Lake Baikal, Russia. It combines field observations in the river basin with soil erosion modelling and aims at quantifying the contribution from natural erosion of metal-rich soil to observed increases in mass flows of metals along the Tuul River. Results show that the sediment delivery from the mining area to the Tuul River is considerably higher than the possible contribution from natural soil erosion. This is primarily due to excessive mining-related water use creating turbid wastewaters, disturbed filtering functions of deposition areas (natural sediment traps) close to the river and disturbances from infrastructures such as roads. Furthermore, relative to background levels, soils within Zaamar Goldfield contained elevated concentrations of As, Sr, Mn,V, Ni, Cu and Cr. The enhanced soil loss caused by mining-related activities can also explain observed, considerable increases in mass flows of metals in the Tuul River. The present example from Tuul River may provide useful new insights regarding the erosion and geomorphic evolution of mined areas, as well as the associated delivery of metals into stream networks.

  相似文献   

13.
INTRODUCTION: A study was conducted as a result of concern about mercury absorption amongst residents of a peri-urban area in Cape Town, South Africa, in close proximity to waste disposal sites and an industrial area. STUDY METHODS: The study compared urine mercury concentrations in a random sample of adult residents and children in both the formal and informal housing settlements of the "exposure" area (n = 90) and a control area (n = 90). A short questionnaire elicited demographic, lifestyle and medical details and possible occupational, household and environmental mercury exposures. RESULTS: The two samples were comparable with respect to background and potential confounding variables. The prevalence of urinary mercury levels>or=the WHO reference range in the exposure area was also higher than that in the control area (13% vs. 0%). The median urinary mercury concentrations in both study areas were below the World Health Organisation (WHO) reference level of 5.0 microg/g creatinine. The median level in the exposure area was slightly, but statistically significantly, higher than in the control area (1.1 vs. 0.25 microg/g creatinine), and the excess persisted after controlling for known possible mercury exposures. CONCLUSIONS: This is to our knowledge the first study of community inorganic mercury absorption in a developing country setting, and where airborne mercury was the exposure of concern. It was concluded that the health risk associated with the urinary mercury levels of residents in the exposure area was very low. However, low level environmental exposure in the area of concern could not be excluded.  相似文献   

14.
The Swedish parliament has decided that the use of mercury (Hg) in society should be phased out by the target year 2000 and substituted with alternative, less harmful elements or compounds. This is to reduce exposure to the toxic heavy metal, levels of which have increased two to seven times in the Swedish environment during the last century. Mercury in products and goods in use in Sweden has been estimated at 100 tonnes Hg, which will slowly be released into the environment if no preventative measures are taken. To avoid handing over unsolved environmental problems and connected costs to future generations, the Swedish government commissioned the Swedish Environmental Protection Agency (EPA) to improve the efficiency of Hg collection and to find a solution for terminal storage of the waste. The result is that the Swedish EPA considers deep storage in rock, accompanied by technical measures to further reduce the risk of future Hg emissions to be the safest method. It has funded approximately 50 projects with the goal of spreading information about the Hg problem and removing Hg from society. The projects have focused on areas where there is a great risk of Hg in products and goods entering the environment. About 6 tonnes Hg has so far been collected in these projects – end of 1999 – and the cost of the Hg collected has varied between 70 and 1300 US$ kg–1 Hg. The projects were more cost-effective than traditional inspection by an official due to local participation, use of Hg-tracker dogs, and employment of professional electricians in the search for Hg. The involvement of school children and the public has resulted in an increased awareness of environmental matters, and, together with the emptying of water seals, reduced Hg levels in municipal sewage sludge. Electronic Publication  相似文献   

15.
The work presents the radioecological characterization of the new Brazilian uranium mining and milling site located in a semi-arid region of the country. The process characterization demonstrated that in heap leach plants most of the 226Ra remains in the leached ore. Despite the potential higher availability of radium isotopes in the soils of the studied region the lack of precipitation in that area reduces the leaching/mobilization of the radionuclides. High 226Ra and 228Ra concentrations were found in manioc while 210Pb was significant in pasture. It was suggested that a range from 10(-3) to 10(-1) may conveniently encompass most of the transfer factors (TF) values for soil/plant systems (i.e. involving different cultures, different soils and natural radionuclides). Impacts due to aerial transportation of aerosols and radon generated in the mining were proved to be minimal and restricted to an area not greater than 15 km2. Finally, uranium complexation by carbonates was shown to be the main mechanism responding for the elevated radionuclide concentration in groundwater.  相似文献   

16.
Mercury (Hg) in soils has increased by a factor of 3 to 10 in recent times mainly due to combustion of fossil fuels combined with long-range atmospheric transport processes. Other sources as chlor-alkali plants, gold mining and cement production can also be significant, at least locally. This paper summarizes the natural and anthropogenic sources that have contributed to the increase of Hg concentration in soil and reviews major remediation techniques and their applications to control soil Hg contamination. The focus is on soil washing, stabilisation/solidification, thermal treatment and biological techniques; but also the factors that influence Hg mobilisation in soil and therefore are crucial for evaluating and optimizing remediation techniques are discussed. Further research on bioremediation is encouraged and future study should focus on the implementation of different remediation techniques under field conditions.  相似文献   

17.
Sediment samples were analyzed for Cd, Cr, Cu, Pb, Hg and Zn by AAS. The highest concentrations (ppm) for Cu (26.1+/-4.8), Hg (0.2+/-0.05), Pb (30.7+/-5.6) and Zn (45.4+/-13.1) were found at approximately 25 m from the shoreline. Generally, heavy metals concentration in the sediment decreased with increasing distance from the shoreline except for Cd and Cr whose highest concentrations were found at approximately 2000 m from the shoreline.The data also indicated that sediment samples which were collected at the shores within the urban area of Mwanza showed elevated levels of Pb (54.6+/-11.1 ppm) and Zn (83.7+/-21.5 ppm). However, the highest concentrations of Cd (7.0+/-2.1 ppm), Cr (12. 9+/-1.0 ppm) and Hg (2.8+/-0.8 ppm) were recorded at sampling stations which were adjacent to river mouths.  相似文献   

18.
The northern aplomado falcon (Falco femoralis septentrionalis) disappeared from south Texas in the 1940s. Due to great success in the release of captive-reared aplomado falcons in south Texas, there are currently more than 40 established nesting pairs in the region. Addled eggs from aplomado falcons nesting in northern Chihuahua and south Texas were analyzed to determine organochlorine (OC) and inorganic element contaminant burdens and their potential association with egg failures and effects on reproduction. Among the OCs, DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] was present at the highest concentrations (range 262-21487 ng/g wet weight) followed by polychlorinated biphenyls (PCBs, range 88-3274 ng/g ww). DDE was greater (P=0.03) in eggs from El Sueco (Chihuahua, Mexico) than in those from Matagorda Island (Texas, USA). DDE concentrations in eggs of aplomado falcons from El Sueco were elevated; however, reproductive success in the two Chihuahuan populations did not seem to be affected by DDE. DDE and metals in potential avian prey of the aplomado falcon from Matagorda Island were very low and below levels in the diet at which some negative effects might be expected. Except for mercury (Hg), metal concentrations in eggs were fairly low and were not different among locations in Chihuahua and south Texas. Hg was somewhat elevated and was greater (P<0.001) in Texas than in the Chihuahua locations. Periodic monitoring of Hg concentrations in addled eggs of aplomado falcons in south Texas is recommended to continue evaluating potential negative effects on their recovery.  相似文献   

19.
We describe a three step process for the removal of uranium (U) from dilute waste waters. Step one involves the sequestration of U on, in, and around aquatic plants such as algae. Cell wall ligands efficiently remove U(VI) from waste water. Growing algae continuously renew the cellular surface area. Step 2 is the removal of U-algal particulates from the water column to the sediments. Step 3 involves reducing U(VI) to U(IV) and transforming the ions into stable precipitates in the sediments. The algal cells provide organic carbon and other nutrients to heterotrophic microbial consortia to maintain the low E(H), within which the U is transformed. Among the microorganisms, algae are of predominant interest for the ecological engineer because of their ability to sequester U and because some algae can live under many extreme environments, often in abundance. Algae grow in a wide spectrum of water qualities, from alkaline environments (Chara, Nitella) to acidic mine drainage waste waters (Mougeotia, Ulothrix). If they could be induced to grow in waste waters, they would provide a simple, long-term means to remove U and other radionuclides from U mining effluents. This paper reviews the literature on algal and microbial adsorption, reduction, and transformation of U in waste streams, wetlands, lakes and oceans.  相似文献   

20.
A field survey of herbaceous growing on lead-zinc mining area in Yunnan, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Zn and Cd in shoots. In total, 220 plant samples of 129 species of 50 families and 220 soil samples in which the plants were growing were collected. According to accumulation concentration in plant shoots and the concentration time levels compared to plants from non-polluted environments, 21 plant samples of 16 species were chosen as best-performing specimens, 11 plant samples of 10 species for Pb, 5 plant samples of 4 species for Zn and 5 plant samples of 5 species for Cd. Sonchus asper (L.) Hill in Qilinkeng had hyperaccumulation capacity to Pb and Zn. Corydalis pterygopetala Franch in Paomaping had hyperaccumulation capacity to Zn and Cd. All 5 Cd hyperaccumulators came from Lanping lead-zinc mining area. Out of 11 Pb hyperaccumulators, 7 came from Minbingying of Huice lead-zinc mining area. The average of the concentration time levels compared to plants from non-polluted environments were higher than 10 times in all plant samples, the concentration time levels changed from 203 times to 620 times for Pb, from 50 times to 70 times for Zn and from 145 times to 330 times for Cd. Out of 21 plant samples, translocation factor changed from 0.35 to 1.90, only translocation factor of 7 plant samples were higher than 1. Enrichment coefficients of all samples were lower than 1. These plant species were primarily heavy metal hyperaccumulator, and will be used in phytoremediation of the metallic pollutants in soils after further research in accumulation mechanism.  相似文献   

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