Alterations of reproductive parameters in the crab Carcinus maenas after exposure to metals

The objective of this study was to investigate the effects of acute exposure to copper, chromium and mixtures of these metals on reproductive parameters of female Carcinus maenas. The parameters studied were ovarian esterase, acid and alkaline phosphatase activity, ovarian protein content, gonadosomatic index (GSI) and hepatosomatic index (HSI). Metals induced significant decreases on ovarian alkaline phosphatase activity, esterase activity and protein content. Ovarian acid phosphatase activity significantly increased in crabs exposed to chromium, while only a slightly increase was found in females exposed to copper and to mixtures of these metals. Furthermore, a dose-dependent reduction of both GSI and HSI were observed in crabs exposed to metals. These observations suggest that copper and chromium may interfere with the ovarian cycle in Carcinus maenas and, therefore, with the reproduction of this species. In general, the mixture had more pronounced effects than individual metals. This subject requires further investigation because in polluted estuaries, crabs may be simultaneously exposed to several metals.     

Mercury Accumulation in Sediments of a Mangrove Ecosystem in SE Brazil

The Hg accumulation in sedimentary environments of a mangrove ecosystem in Sepetiba Bay, SE Brazil, was investigated. These environments include sediments of a mangrove forest, the main tidal creek that drains the forest, and the bare seaward-edge mud flat adjacent to forest and tidal creek. Maximum Hg concentration peaks in sediments from the mud flat (184 ng g^-1), tidal creek (98 ng g^-1), and mangrove forest (60 ng g^-1) correspond to enrichment factors of 6.1, 3.3, and 2.0 above the estimated average background level, respectively. Average inventories of Hg excess (background-corrected) concentrations were substantiallydifferent between environments, decreasing from mud flat sediments (5.2 mg m^-2) to creek sediments (3.3 mg m^-2)to mangrove forest sediments (0.9 mg m^-2). Mercury concentration profiles indicated a consistently higher accumulation of Hg in surface layers of mud flat and tidal creeksediments, whereas mangrove forest sediments showed a higher Hgaccumulation in root-rich subsurface layers, in agreement with an enrichment of Fe and organic matter contents. While Hg distribution in mud flat and tidal creek sediments appears to belargely affected by contamination, its distribution in mangrove forest substrate appears to be greatly affected by root-sedimentinteractions. Mercury levels in the study site were comparable tothose observed in coastal sediments under moderate Hg contamination at local and regional scales. Results indicate thatsedimentary environments surrounding the mangrove forest retain most of the anthropogenic Hg reaching the ecosystem. Since tidal waters have been previously demonstrated as the main source of metals to the site, it is suggested that the Hg retention in mudflat sediments precede and may avoid a higher Hg accumulation inlandward environments.     

大气沉降对萝卜地上和地下部分铅镉汞砷积累的影响

为评估大气沉降对蔬菜中重金属积累的潜在影响,选择非污染和污染2种土壤,分别在工业区、城区和农村等3种大气环境下开展露天与大棚种植对萝卜重金属积累的影响试验。结果表明,土壤是萝卜重金属的重要来源,污染土壤中生长的萝卜铅、镉、汞和砷积累明显高于非污染土壤,但试验区大气环境与种植条件对萝卜地上部分重金属含量也有很大的影响,萝卜地上部分重金属含量工业区城区农村,露天种植的萝卜地上部分重金属含量明显高于大棚;大气沉降对大气污染较为严重的工业区萝卜地下部分重金属积累有一定影响,对城区与农村的影响较小。通过清洗方式不能完全清除因大气沉降导致的蔬菜重金属积累,表明由大气沉降的重金属有较高比例已通过蔬菜叶片的气孔进入蔬菜组织内或被蔬菜组织紧密地吸附。研究证实了大气沉降对蔬菜地上部分中镉、铅和汞等重金属积累有直接的作用。     

Distribution and Accumulation of Mercury Derived from Gold Mining in Marine Environment and Its Impact on Residents of Buyat Bay, North Sulawesi, Indonesia

Buyat Bay (BB), North Sulawesi, Indonesia, was a submarine tailings disposal (STD) site for an industrial gold mine that extracted mercury (Hg)-containing ores from 1996 to 2004. To evaluate the distribution and influence of such a Hg release into the environment, particularly into BB, we quantified the total mercury (THg) and methyl mercury (MeHg) in the surface sediments (beach, river estuary, and marine) and biota of the bay, as well as the scalp hair of residents in the adjacent community. A nearby body of water, Totok Bay, polluted by Hg from artisanal gold mining, and a reference area of the Bajo Coast (Bajo) free of any anthropogenic sources of Hg were also sampled. Both THg and MeHg were detected in all samples measured showed concentrations to be highest at the artisanal mining site, intermediate at the STD site and at their lowest in the control area. THg and MeHg concentrations in marine biota and human hair increased with trophic levels and were significantly higher at the STD site than among the controls. Besides examining the source and distribution of Hg, its accumulation in biota, and its potential impact on humans, we also studied the role of the mine management so as to provide a recommendation for future actions.     

Variation in Copper Accumulation at the Tissue Level of Five Hybrid Poplars Subjected to Copper Stress

Heavy metal contamination causes significant environmental problems around the world and poses a threat to human health. Poplar hybrids present features for potential uses in phytoremediation systems in areas with heavy metal contamination. The purpose of this study was to assess the copper (Cu) accumulation level in five poplar inter-species hybrids [(Populus trichocarpa × Populus deltoides) × P. deltoides; P. deltoides × Populus nigra; P. trichocarpa × Populus maximowiczii; P. trichocarpa × P. nigra; and (P. trichocarpa × P. deltoides) × (P. trichocarpa × P. deltoides)] grown in a hydroponic system. The treatments entailed the application of low and high doses of Cu of 8.0 and 16.0 μM, respectively. Cu accumulation was observed in roots, stems, and leaves, which was determined using flame atomic absorption spectroscopy, prior acid digestion of each sample. The methodology was validated according to certified reference material (Cypress BIMEP 432). Significant differences in Cu accumulation were found among genotypes for both roots and leaves, but not for stems. In roots, the genotype P. deltoides × P. nigra had a Cu accumulation level of 169.8% higher than the average accumulation found in the other genotypes. The (P. trichocarpa × P. deltoides) × P. deltoides hybrid showed the least Cu accumulation in leaves. The results of this study can potentially be used for proper crossovers and hybrids selection within the genus Populus for phytoremediation of Cu contaminated land.     

Comparative Study on Trace Metal Accumulation in Liver of Mediterranean Deep-Sea Fish and Their Selenium/Mercury Molar Ratios

The objectives of this study were to determine and compare the concentrations of Hg, Cd, Pb, Zn, Cu, Ni and Se in the liver of macrourid fish as Trachyrinchus scabrus, Nezumia sclerorhynchus and Coelorhynchus coelorhynchus from the Mediterranean Sea, Italy. It was also carried out to evaluate the relationship between metal concentration and fish size and to explore selenium/mercury molar ratio. The highest concentrations were in T. scabrus, followed by N. sclerorhynchus and C. coelorhynchus. In all species, any element displayed significant correlation between metal body burden and fish size, except Hg. The mean selenium/mercury ratios were greater than one in all fish species indicating that Se antidotal effect in counteracting Hg occurred. This report represents one of the few surveys providing information on trace metal in deep-sea fish from Mediterranean Sea constituting, thus, an essential baseline work with which future levels may be compared.     

Kinetics of Mercury Accumulation and Its Effects on Ulva lactuca Growth Rate at Two Salinities and Exposure Conditions

The research on metals effect on macroalgae has been focused on Cd, Cu, Zn and Pb, and no study dealt with the effects of mercury on macroalgae growth rate. Also, the kinetic of accumulation is not well known. The main aim of this work was to assess the mercury accumulation kinetics of Ulva lactuca and its effects on growth rate. Three concentrations were tested: 5, 50 and 500???g?L^?1, under static and renewal conditions and at two salinities (15 and 35), during 72?h. The mercury accumulation kinetic patterns were different according to the exposure conditions and metal concentration, but were always a very fast process (hours). Three patterns were established based on the models substrate inhibition, linear regression and Michaelis?CMenten equation. Statistical differences in the mercury accumulated were recorded depending on the salinity values and exposure conditions, being higher at salinity 15 and at renewal tests, corresponding to the lower relative growth rates. The lowest mercury concentration did not have an effect on relative growth rate, while the others caused an accentuated inhibition at 24?h. The highest concentration was toxic to algae causing its death before 48?h. Under controlled conditions, the U. lactuca??s high and fast ability for mercury accumulation could be useful for phytoremediation and for industrial wastewaters treatment.     

Mercury Speciation in the Water of Minamata Bay, Japan

The speciation of mercury (Hg) in Minamata Bay (Japan) was studied over a 2-year period (2006?C2008). Concentrations of dissolved total Hg, dissolved methylmercury (MeHg), particulate total Hg, and suspended solids were 0.43?±?0.14 ng/l (mean?±?standard deviation), 0.10?±?0.06 ng/l, 3.04?±?2.96 ng/l, and 5.94?±?2.10 mg/l, respectively. Correlations between concentrations of particulate total Hg and suspended solids at four depths (surface: 0 m; mid-depth: ?6 m, ?10 m; and bottom +1 m layer) were only significant in the bottom +1 m layer. The mean dissolved MeHg concentration and the ratio of dissolved MeHg to dissolved total Hg were considerably higher in summer compared to other seasons. The data suggest that bottom sediment was not the sole source of MeHg, and that MeHg may be produced in the water column by the conversion of divalent Hg eluted from resuspended bottom sediment. The correlation between seawater characteristics such as salinity, temperature, dissolved oxygen (DO), and dissolved MeHg concentration indicates that Hg methylation could be influenced by the heterotrophic activity of microorganisms in the seawater. In particular, inverse correlations were observed between DO, salinity, and MeHg concentration. However, dissolved MeHg concentrations did not correlate with seawater characteristics such as pH or chlorophyll-a.     

Mercury transport,transformation, and bioaccumulation in the ecosystem of mercury — stibium geochemical province

A simple analytic technique — isotope dilution — was used for determination of the contents of total and methilated Hg in water, sediments, soils and biological objects collected in the basin of the river Katun. The inspected region is located on a territory of two mercury-stibium geochemical provinces. Evaluation of the Hg transport, transformation and bioaccumulation in aquatic and terrestrial ecosystems of the region showed that the main Hg transport occurs on suspended solids after Hg has been washed out from soil and bedrock by water of the river Katun and its tributaries and also by underground waters. Bottom sediments of some rivers of the basin content increased Hg concentrations. This effect is also noted in the sediments of a small reservoir formed on one of the tributaries. The investigations showed that Hg originating from natural sources differs considerably in its biochemical characteristics from Hg compounds coming from anthropogenic sources. So, natural Hg compounds have lower bioavailability for the water and terrestrial organisms of the region.     

Comparative Study of Lead Accumulation in Different Organs of the Freshwater Crab <Emphasis Type="Italic">Zilchiopsis oronensis</Emphasis>

Lead (Pb) is known as an important aquatic contaminant with different toxic effects on various organisms. Until now, only few quantitative investigations have been published comparing Pb content in different organs of adult freshwater crabs. Their capacity to bioaccumulate other heavy metals is already known, and they can potentially transfer Pb to the terrestrial systems, as they are frequent trophic items of reptiles and birds, even humans. The objectives of this study were to assess Pb accumulation in the gills, carapace, digestive gland, and quela muscle of the freshwater crab Zilchiopsis oronensis, and to correlate bioaccumulation with morphometric data and sex. The crabs were manually caught in unpolluted ponds of the middle Paraná River alluvial valley (Santa Fe, Argentina). After the acclimation period, they were individually and randomly exposed per quadruplicate to three Pb experimental doses: 20, 40, and 80 mg Pb/L, in plastic cages during 15 days. After dissecting the crabs, the tissues were analyzed for lead in a Perkin Elmer Analyst 800 atomic absorption spectrometer. We found significant differences (p < 0.05) between the control and each one of the treatments but not between treatments (p > 0.05) and highly significant differences (p < 0.0001) between Pb concentration in organs. The Tukey posttest showed significant differences (p < 0.05) between gills–carapace, gills–digestive gland, and gills–quela muscle. The weight of the crabs only showed a negative correlation with Pb in the quela muscle (r = −0.53; p = 0.03). Pb in the carapace (but not in the other tissues) was positively correlated with the width (p = 0.571) and length (p = 0.616). Males accumulated more Pb than females, though not significantly. The present paper is aimed to contribute to our knowledge on Pb accumulation in freshwater crabs and select the better indicator organisms for biomonitoring.     

Morphotype relationships in Lima bean (Phaseolus lunatus L.) deduced from variation of the evolutionary marker phaseolin

Summary Variation of the seed storage protein phaseolin was analysed in a collection of 100 accessions of Phaseolus lunatus L. using one-dimensional SDS/PAGE. Cultivated small-seeded genotypes belonging to Sieva and Potato morphotypes and intermediate Sieva-Potato and Sieva-Big Lima morphotypes showed the M (Mesoamerican) pattern, confirming their origin in the same gene pool. Cultivated Big Lima morphotypes showed the A (Andean) pattern, confirming that they belong to a distinct gene pool.     

Mercury distribution in humus and surficial sediments,Flin Flon,Manitoba, Canada

Regional humus and surficial sediments were collected in the vicinity of a base metal smelter in Flin Hon. Results of total mercury (Hg) analyses indicate that enrichment in humus is related to emissions from the smelter stack up to a distance of 40 km. In the immediate vicinity of the point source, total Hg values reach as much as 250 times the regional background (400 ppb). This enrichment is not reflected in the underlying surficial sediments. The Hg distribution pattern is similar for other known metal pollutants emitted from the smelter.     

贵州省万山汞矿区周围土壤中不同形态汞的空间分布特征

利用连续提取法对贵州省万山汞矿区周边土壤的形态与分布特征进行了测试分析。结果表明,研究区土壤中汞含量在1.34～291.71mg·kg-1之间,明显高于我国土壤汞背景值。表层土壤中汞含量在东部区域普遍较高,西部区域相对较低,并呈现随距污染源距离的增加逐渐降低的趋势。剖面土壤中的汞则表现出明显的表层富集规律。研究区土壤中汞的形态主要以残渣态、难氧化降解有机质及某些硫化物结合态和易氧化降解有机质结合态汞为主,且不同形态的汞含量与总汞含量具有较大的相关性。     

Mercury in plants,soil and atmosphere near a chlor-alkali complex

Data of atmospheric Hg concentrations measured near the chlor-alkali complex of Rosignano Solvay (Livorno, Italy) show that the impact of the industry on the terrestrial environment is restricted to a close area around; background values (3 to 5 ng m^?3) are reached within a radius of 4 to 5 km. Hg levels in plants (Poa sp. Pinus nigra and Solidago sp.) and in soil show the highest values in the sampling stations near the electrolytic cells.     

A mass Budget for Mercury in the Willamette River Basin, Oregon, USA

In Oregon’s Willamette River Basin (Basin), health advisories currently limit consumption of fish that have accumulated methylmercury. Under the Clean Water Act, these advisories create the requirement for a mercury Total Maximum Daily Load (TMDL), which, in turn, created the need to better characterize the cycling of mercury in the Basin. This paper presents: (a) a mass balance model relating the processes, reservoirs, and fluxes of the Basin’s mercury cycle, (b) first-approximation estimates of reservoir masses, flux rates, and turnover times, and (c) an assessment of the impact of anthropogenic mercury sources on this cycle. Deposition from the atmosphere to land is estimated to be the largest (587 kg yr^?1) single flux; with much (≈54%) of this deposited mercury returned to the atmosphere via volatilization. Combined local anthropogenic (360 kg yr^?1) and global emissions (390 kg yr^?1) substantially overshadow all other anthropogenic point-source inputs. Runoff of mercury from native soils (particulate and dissolved phases) was estimated as the largest (≈70%) single source of Hg to surface water; contributions from anthropogenic air emissions deposited on land and then transported as runoff were ≈17%. All other currently identified and quantifiable non-atmospheric anthropogenic point sources made a small (≈5%) contribution to total loadings. These first-approximation estimates suggest that management of soil erosion should have a higher priority than reductions in local anthropogenic air emissions, with the caveat, however, that the degree of linkage between any such reductions and that of methylmercury levels in fish is presently unclear. Additional work will be required to develop the better parameterized and calibrated model needed to predict the outcome of Hg loading reduction alternatives under consideration within the TMDL process.     

太湖地区河蟹“养殖-净化”复合系统氮磷循环模拟模型研究

以"养殖-净化"复合系统为对象,探讨河蟹养殖尾水达标排放(地表Ⅲ类水)的工程与技术措施。通过构建系统动力学模型,模拟河蟹养殖尾水达标排放的最佳养殖塘与净化塘的面积比,及不同饵料替代比例、水质调控技术与净化效率对养殖塘和净化塘水体TN和TP浓度的影响。模拟结果显示,在常规养殖条件下,要使净化尾水达到地表Ⅲ类水标准,养殖塘与净化塘的最佳面积比为20.5∶1。商品饲料代替5%、10%和15%时,养殖塘TN浓度分别降低3.1%、6.3%和10.0%,TP浓度分别降低4.2%、8.3%和8.3%;净化塘TN浓度分别降低4.5%、10.1%和14.6%。养殖塘水质调控技术对养殖塘和净化塘水体的TN和TP浓度无显著影响。与水葫芦收获1次相比,收获2次和3次的养殖塘TN浓度分别显著降低10.0%和10.0%,TP浓度降低11.1%和11.1%;净化塘TN浓度分别降低16.1%和17.2%。水葫芦收获2次与3次对养殖塘和净化塘水体TN、TP浓度变化无显著影响。以上结果表明,河蟹养殖工程可以按照养殖塘与净化塘的面积比为20.5∶1进行构建,二塘水体的TN、TP浓度随商品饲料替代比例增加而降低;净化塘水葫芦只需收获2次,净化水质即可达标地表Ⅲ类水。     

Mercury in soils of British Columbia,a mercuriferous region

Mercury concentrations in various horizons of British Columbia soils were determined to estimate natural background levels in soils from various geographical areas of the province. Highly enriched concentrations near the Pinchi Lake cinnibar deposit declined to background levels ranging from 10 to 310 ppb Hg in the district. In six other regions, concentrations in surface mineral horizons averaged 85 ppb and ranged to 490 ppb but surface horizons of peaty muck soils and those predominated by vegetative litter contained 164 ppb Hg on the average and as much as 741 ppb. Concentrations in subsurface horizons were lower than at the surface. A significant relationship between Hg concentration and organic matter content was observed. Comparison with soils from outside British Columbia indicated its location within a generalized mercuriferous belt accounted for the relatively high concentrations observed.     

Mercury in fish in the Smallwood Reservoir,Labrador, twenty one years after impoundment

The elevated mercury (Hg) levels in fish flesh found after impoundment of a reservoir, are predicted to decline as the reservoir ages. The length of time required for a return to background levels is dependent on among other things, the trophic status of the fish. Predictions for omnivorous species range between 15 and 20 years while for piscivorous species they vary from 20 to 30 years. Fish in the Smallwood Reservoir, Labrador, Canada, were sampled 6 years after impoundment when hg levels were found to be elevated in most species. Selected of the sites were re-sampled after 16 years and again after 21 years. Mercury in the flesh of omnivorous species such as lake whitefish (Coregonus clupeaformis) had returned to background levels after 16 years as predicted. However, hg in the flesh of piscivores such as northern pike (Esox lucius) and lake trout (Salvelinus namaycush) remained elevated even 21 years after impoundment. While the levels in lake trout have declined somewhat in that time, there is no evidence of decline in the northern pike either within the reservoir or at downstream stations. Models predicting decline in hg levels in piscivorous fish in reservoirs must be re-evaluated in light of this extended data set.     

Assessing the Influence of Different Atmospheric and Soil Mercury Concentrations on Foliar Mercury Concentrations in a Controlled Environment

This study vividly presents results from a seasonal particulate matter measurement campaign conducted at world’s largest ship-breaking yard i.e., Alang-Sosiya (Gujarat, India) at six locations and a reference station at Gopnath which is 30 km south of this ship-breaking yard. The collected suspended particulate matter (SPM) 24-h samples were critically analyzed for heavy metals (Pb, Cd, Co, Ni, Cr, Mn, Fe, Cu, Zn). The average concentration of SPM within the ship-breaking yard during the investigation was 287.5 ± 20.4 μg m^?3 and at reference station it was 111.13 ± 5.81 μg m^?3. These values are found to be in excess of the permitted national standards. The levels of heavy metals at Alang-Sosiya are very high as compared to US EPA and WHO guidelines. The mean concentrations of all metals are in the order: Fe >>Zn >Cu > Mn > Cd >Pb > Co >Ni >Cr. The results on enrichment factors (EF) suggest that most of the metals in the ship-breaking yard exhibit EF values of near or above 100 which must have been comprehensively affected by ship-breaking activities. Metal data was used to evaluate the role of spatial factors on their distribution characteristics. Thereafter, factor analysis was carried out to identify the main components liable for the variance of the data set.