Distribution of Mercury and Other Trace Metals in the Cockle Cerastoderma glaucum from the Mediterranean Lagoon Etang de Thau

The concentrations of Ag, Cd, Co, Cr, Cu, Ni, Pb, Zn, Mn, and Fe in the soft tissue of the cockle Cerastoderma glaucum from six sites along the Mediterranean Lagoon Etang de Thau were determined by AAS; Hg was determined by the cold-vapor technique. Significant spatial variations in metal concentrations within the lagoon were recorded. Elevated levels of tissue Pb, Cr, and Hg in the Etang des Eaux Blanches, an area adjacent to the harbor and highly industrialized region, are likely of anthropogenic origin. Seasonally dependent variations in the tissue concentrations of trace elements at Crique de l'Angle were observed. The highest levels of Cr and Pb in the tissue were identified in March 1992, of Hg, Co, and Fe in period August 1990–January 1991, of Mn in August 1992, and Ag in January 1991. The gills contained the maximum amounts of Co and Ni, the mantle the most Fe and Hg, and the digestive gland (hepatopancreas) had most Cu. Received: 10 February 1998/Accepted: 6 July 1998     

Distribution of heavy metals and their age-related changes in the eastern great white egret,Egretta alba modesta,in Korea

Organ and tissue distribution of eight metals (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Hg) and their age-related changes were investigated in the chick and adult eastern great white egret,Egretta alba modesta, collected in Korea. High concentrations of the metals were found in the liver, kidney, feathers, bone, and skin; low values were found in the muscle and brain. A majority of the metal burdens in the chick and adult egrets existed in the muscle, bone, and feathers; about 50% of the Hg was in the feathers. The concentrations of Fe, Mn, Zn, and Cu in organs and tissues of the chicks characteristically changed with age, and their accumulations depended upon the metabolic turnover. In contrast, the concentrations of Pb, Ni, Cd, and Hg increased with age, suggesting that age or exposure time is a dominant factor. However, the younger stage of the downy chicks showed a rapid accumulation plateau of Pb, Ni, Cd, and Hg, and a dilution effect of these metal concentrations by increased body weight with age also was observed. Furthermore, rapid decreases of the body burden of Mn, Cu, Ni, Pb, Cd, and Hg were found in the fledgling birds, indicating that the metals were excreted via the feathers by moulting. These results indicate that consideration of the growth stage of organs and tissues is necessary for understanding the bioaccumulation processes and the toxicological criteria of the metals.     

Anthropogenic Sources of Heavy Metals in the Indian Ocean Coast of Kenya

Water and surface sediment samples from Rivers Sabaki, Ramisi and Vevesi that flow into the Indian Ocean coast of Kenya were analysed for heavy metals. The sediment concentrations of exchangeable cations (in μg/g) for Co, Cu, Mn, Ni, Pb, Sn and Zn ranged from 0.10 to 506.75 (for Mn at Sabaki), constituting between 2% and 20% of the total metal concentrations obtained by digestion with strong acid. Cu, Mn, Ni, Pb and Zn were more leachable with 0.1 N HCl. The total dissolved metal in water and the total sediment concentrations for Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn and Zn are given in the text. For dissolved metals, the metal/Mn ratios indicated higher concentrations of Ag in Sabaki River, Cd in Ramisi, Ni in Sabaki and Pb in Ramisi, respectively. In sediments, the metal/Mn ratios showed higher enrichment of Ag in Ramisi, Cd in Sabaki and Vevesi, and Zn in Sabaki, respectively. Enrichment factors showed elevated levels of Cd, Pb and Zn in sediment in River Sabaki and River Vevesi that were due to anthropogenic inputs through Athi River. The total dissolved metal concentration ranges for the three rivers were comparable with those ranges reported in rivers in South Africa but the sediment concentrations were below those of rivers in Europe and Asia where anthropogenic addition of some of the toxic elements such as Cu, Pb and Cd is evidently higher.     

Heavy-Metal Concentrations in Female Laying Great Tits (Parus major)and Their Clutches

Egg laying may be an additional excretory pathway for heavy metals available to laying female birds. In this study, we examined the relationships between tissue concentrations (both internal organs and feathers) of 10 breeding female great tits (Parus major) and the concentrations in their eggs. We also investigated differences in metal concentrations (Ag, Al, As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) among eggs as a result of the laying order of the eggs. Heavy-metal concentrations in internal tissues were highest in bone (Cr, Ni, Pb, Zn), kidney (Cd), liver (Cu), blood (Al, As, Co, Hg), and intestine (Ag, Mn). In the egg contents, relatively high concentrations of the essential elements Cr, Co, Cu, Mn, Ni, and Zn were found. In eggshells, concentrations of Ag, Al, As, Co, Cr, and Ni were high compared with internal tissue concentrations. Metal concentrations in the egg contents and eggshells were poorly correlated with metal concentrations in internal tissues and feathers; significant positive correlations were found only for cadmium and lead. We found few significant differences in metal concentrations among eggs, and none were according to the laying order of the eggs. The egg volume tended to decrease significantly as egg laying progressed. Our results seem to suggest that no special sampling strategies (e.g., sampling the first egg or pooling eggs from one clutch) are required for most metals.     

Toxic element concentrations in the Razorbill Alca torda (Charadriiformes, Alcidae) in Portugal

The present study provides the first data on inorganic element levels (As, Cd, Co, Cr, Cu, Hg, Mn, Pb, Se, and Zn) in juvenile, immature, and adult razorbills (Alca torda) collected along the central coast of Portugal. Element concentrations were assessed by ICP-MS in kidney, liver, muscle, and feathers of 28 razorbills, including 4 juveniles, 17 subadults, and 7 adults. The effect of age and tissue on element accumulation was also assessed. The detected levels in razorbills may indicate a possible contamination risk by Hg and Cr. With respect to bird tissues, higher accumulation of Se and Cd was detected in kidney, Zn and Pb in feathers, and As and Mn in liver. Age was found to affect the accumulation of Cd, Cr, Cu, Hg, and Mn, juveniles presenting higher levels of Cu and Mn than older individuals. In razorbill kidney, Zn–Hg constituted the most significant relationship among metal concentrations. Liver presented the highest number of significant relationships (mostly involving Zn and Co). With regard to feathers, the most significant relationships involved Se, Zn, Cr and Cu concentrations. Positive linear relationships were detected among kidney, liver, and muscle, with emphasis on relationships involving Se and Hg, which may be indicative of similar accumulation/regulation mechanisms in those organs. Element concentrations are discussed in view of possible detoxification mechanisms in seabirds.     

Utilization of morphometric analysis in evaluating response ofPlectonema boryanum (Cyanophyceae) to exposure to eight heavy metals

The techniques of morphometric analysis were used to study the ultrastructural changes induced inPlectonema boryanum (Cyanophyceae) by heavy metal exposure. Four of the test metals (Mn, Zn, Hg, and Cd) produced no changes in overall cell dimensions. Two metals (Pb and Cu) produced significant increases in cell size and two other metals (Co and Ni) caused significant decrease in cell size. Mn, Pb, Co, Ni, and Cd caused significant increases in the surface area of the cell's thylakoids and Ni, Co, Zn, and Hg caused a significant reduction in the volume of the intrathylakoidal spaces. All tested metals except Pb and Mn caused the production of extra intracellular membrane whorls. Pb, Mn, Co, Zn, Hg, Cd, and Ni caused coalescence of cellular lipid while Cu caused a reduction in cellular lipid content. Co caused a reduction in the number of polyhedral bodies and Cd caused an increase in the volume of the cell's polyphosphate bodies. The physiological significance of these findings are discussed in terms of potential toxic action of cations and the cellular mechanisms for the detoxification of cations once they enter the cell. Common mechanisms of both procaryotic and eucaryotic algae are discussed and the utilization of stereological techniques for electron microscopic morphometric analysis is established in studies of metal toxicity at the cellular level.     

Distribution of 14 Elements in Tissues and Organs of Oceanic Seabirds

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 μg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 μg/g dry weight). Received: 30 October 1997/Accepted: 17 May 1998     

Distribution and Association of Trace Metals in Soft Tissue and Byssus of Mytilus edulis from the East Coast of Kyushu Island, Japan

Concentrations of Cd, Pb, Zn, Cu, Ag, Cr, Co Ni, Mn, and Fe in soft tissues and byssi of blue mussel (Mytilus edulis) from three sites along the east coast of Kyushu Island, Japan, were determined by AAS method. Large inter-regional differences in metal concentrations in both soft tissues and byssi (Cu, Cd, and Pb and Cu, Pb, Co, Ni, Mn, and Fe, respectively) were recorded. Highly significant correlations (p < 0.01) were observed between tissue and byssal concentrations of Pb, Cu, Zn, and Mn. The tissue concentrations of Cu, Cd, and Pb were two orders of magnitude greater in Mytilus edulis from expected to be the most contaminated locations compared to those from a nonindustrialized area. Intercomparison of the present study data with those published previously indicates that the soft tissue and especially byssus are useful in detecting some areas of some metallic contaminants. The high concentrations of Cd, and especially Pb and Cu, in Saganoseki mussels and moderately elevated concentrations of these metals in Akamizu mussels may be attributed to the anthropogenic emissions from a metallic refinery and an artificial fiber factory, respectively. It is evident that, compared to the soft tissue, the increase of Cu levels relative to Zn levels in the byssi of M. edulis are eight times higher, with a slope b (Cu/Zn) of 7.5 for byssus and 0.93 for soft tissue. This suggests that byssus, as compared to soft tissue, is a more sensitive bioindicator for Cu. From the data obtained, the soft tissue and especially byssi of M. edulis appear to be good bioindicators for identification of coastal areas exposed to metallic contaminants. Received: 29 January 1996/Revised: 19 June 1996     

Heavy metals in three lakes in West Poland.

Concentrations of heavy metals (Ni, Cr, Co, Zn, Mn, Pb, Cd, Cu, Hg, Fe) as well as macronutrients (P, Ca, Mg) were measured in water, bottom sediments, and plants of three lakes in West Poland (southwest of Poznan). The plants collected were Nymphaea alba, Nuphar luteum, Ceratophyllum demersum, Phragmites communis, Typha latifolia, and Schoenoplectus lacustris. These plants contained elevated levels of Co, Zn, Pb, Cd, Cr, and Hg. Analyses of water and bottom sediments indicated that the lakes were polluted with Zn, Cd, Cu, and Pb and partly with Ni and Hg. Strong positive correlations were found between concentrations of Cd in water and in plants, between concentrations of Cd in bottom sediments and in plants, between concentrations of Cr in water and in plants, between concentrations of Cr in bottom sediments and in plants, and between concentrations of Fe in water and in plants, indicating the potential of plants for pollution monitoring for these metals. A negative correlation was found between biomass production and Pb and Mn content in water and Pb and Mn content in bottom sediments. Cr and Cd accumulated in plants at a higher rate from bottom sediments than from water. The accumulation rate of Fe in plant tissues was higher with an increase in Fe in water than with an increase in Fe in bottom sediments.     

Observations on metal concentrations in tilapia (Oreochromis mossambicus) in reservoirs of south Sri Lanka

Samples of the muscle and liver of tilapia (Oreochromis mossambicus) obtained from the five reservoirs in four catchments in southern Sri Lanka in 1998 were analyzed for 16 elements: As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn by inductively coupled plasma emission spectrophotometry, and Hg by atomic absorption spectrophotometry. The concentrations of Cr, Ni, and Pb were below the detection limits of the instrumental techniques employed in all samples. The elements As, Ca, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Sr, and Zn were detected in the muscle and liver tissue, with Cd detected in some liver samples. There were no statistically significant differences between the individual concentrations of any of the metals and the site from which the tilapia were collected (P>0.05). Furthermore, no statistically significant correlations were found between total length of fish and metal concentration. No elements were found at concentrations of toxicological concern. However, a principal component analysis suggests that the populations of tilapia in the reservoirs may be exposed to different regimes of metals, possibly associated with different catchment land-use patterns.     

Heavy-metal contamination and solid-phase fractionation in street dust

Fourteen street-dust samples were collected from Hamedan, western Iran. Street-dust samples received different amounts of heavy-metal pollution. The samples were analyzed for total cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn), and binding forms of heavy metal were determined in five fractions. The results showed Cd was the only metal present appreciably, 25.21% and 25.92%, in the exchangeable and carbonates fractions, respectively, and Cu was the only metal predominantly associated, 31.77%, with organic fraction. Zn, 45.84%, was present mainly in the Fe–Mn oxide fraction, and the residual fraction was the most dominant solid phase pool of Ni and Pb, respectively, with 42.56% and 41.31%. The order of apparent mobility and potential metal bioavailability for these contaminated street-dust samples is Cd > Zn > Cu > Pb > Ni. The risk-assessment code results showed very high risk for Cd; medium risk for Cu, Pb, and Zn; and low risk for Ni.     

Metal distribution in the earthworm,Pheretima hilgendorfi,and their variations with growth

The concentrations and distribution of metals (Fe, Mn, Zn, Cu, Pb, Ni, Co, As, Hg, and Cd) in an earthworm,Pheretima hilgendorfi, and their variations with growth were investigated. Higher concentrations of the metals were found in the pre-clitellar regions of the earthworm compared with the post-clitellar ones; Cd, Cu, and Hg were relatively high in the gut wall. The body concentration of Pb and Hg decreased with increased body length (age) and weight, while the opposite was found for Cd and As. The accumulation of Fe, Mn, Zn, Cu, Ni, and Co in the earthworm depends primarily on the metabolic turnover, whereas the accumulation of Pb, Hg, Cd and As, is dependent upon the age or exposure time. Small earthworms showed faster uptake and excretion rates of Pb and Hg than the large ones, and the biological half-lives of Pb and Hg were relatively short compared with those of Cd and As. The large earthworms exhibited a decrease of Hg in the bodies, probably due to excretion of Hgvia spawning. Based upon these results, the sizes and parts of the earthworm suitable for purposes of research are discussed.     

Assessment of Heavy Metal Contents in Surface Soil in the Lhasa–Shigatse–Nam Co Area of the Tibetan Plateau,China

Eight important heavy metals (As, Cr, Cu, Ni, Pb, Zn, Mn, and Hg) were investigated in surface soil samples collected from the Lhasa–Shigatse–Nam Co region, Tibetan Plateau, China. The mean contents of As, Cr, Cu, Ni, Pb, Zn, Mn, and Hg in the samples were 39.5, 57.4, 28.5, 48.2, 15.7, 79.2, 637 and 0.0175 mg/kg, respectively. All metals were divided into three clusters by cluster analysis. The results of geoaccumulation index indicated that no samples were polluted by Cr, Pb, Zn, and Mn, and samples were polluted with As, Cu, Ni, and Hg to different degrees. All surface soils had a low ecological risk with potential ecological risk index below 150, indicating a low ecological risk. As, Pb, and Hg were the primary contributors to potential ecological risk.     

Tissue distribution of heavy metals and their variations with age,sex, and habitat in Japanese serows (Capricornis crispus)

Baseline data on heavy metal accumulations (Fe, Mn, Zn, Cu, Co, Ni, Pb, Cd, and Hg) in organs and tissues, and their variations with age, sex, and habitat in free-ranging Japanese serows were determined. The metal concentrations were high in liver and kidney and low in brain and muscle. Also, high accumulations of Mn and Ni in gastrointestinal organs may be due to an undeveloped excretory system for these metals by bile. About 40% of the Hg burden in the whole body was in the fleece, indicating that a major portion of Hg body burden is excreted by moulting. The metal concentrations varied widely with metal species and also with growth stage or age, especially during the fetal, fawn and puberty periods. Metal burdens of the fetus were very low compared with those of their mothers, so parturition did not change the whole-body burdens/concentrations of metals in the mothers. Iron in the muscle and liver, and Cu in the liver showed significantly higher concentrations in the males than in the females. A significant difference of Cd concentrations was found between habitats of the serow.     

Comparative studies on trace metal levels in marine biota : III. Typical levels and accumulation of toxic trace metals in muscle tissue and organs of marine organisms from different European seas

In 15 marine species of different trophic levels from the Mediterranean Sea, North Sea, and Baltic Sea (> 100 specimens) and selected tissue samples, Cd, Pb, Hg, and Cu, and in several species also Ni and As, have been determined. The routinely applied methods were several versions of atomic absorption spectrophotometry. Accuracy of the obtained data was checked by differential pulse anodic stripping voltammetry (Cd, Pb, Cu), by the application of working standards, Standard Reference Materials, and the participation in external intercomparison programs. Mussels (Mytilus galloprovincialis) and algae (Ulva lactuca) from the Gulf of La Spezia showed the expected efficient accumulation of Cd, Pb, Ni, Cu, and As, while Hg values were comparatively low. Muscle tissue from teleost fishes, which, particularly in certain pelagic organisms of the Mediterranean Sea, contains elevated Hg levels as methyl-Hg, shows in all specimens studied very low Pb levels, 0.01 μg/g (ppm) fresh wt, and Cd levels, 0.003 μg/g (ppm) fresh wt, i.e., below and close to the practically attainable determination limit, respectively. Muscle tissue of mollusks and crustaceans (e.g., Sepia officinalis and Portunus sp.) had considerably higher Cd and also Cu levels compared with those of teleost fishes. Cd values in the ppm range found in the liver of the pelagic fishes Atlantic mackerel (Scomber scombrus) and Atlantic horse mackerel (Trachurus trachurus) from the North Sea were only slightly reflected in muscle meat. Pb levels in organs of all specimens analyzed were quite moderate, even in bone; Hg levels in several liver samples showed roughly about the same order of magnitude as observed in muscle tissue and remained remarkably lower in the gastrointestinal tract and bone.     

Distribution and Accumulation of Metals in Tadpoles Inhabiting the Metalliferous Streams of Eastern Chalkidiki, Northeast Greece

The present study investigates the accumulation of heavy metals [copper (Cu), lead (Pb), zinc (Zn), magnesium (Mn), cadmium (Cd), nickel (Ni), and chromium (Cr)] in tadpoles inhabiting the metalliferous streams flowing within the Asprolakkas River basin (northeast Chalkidiki peninsula, Greece) and the effect of potentially harmful elements in stream water and sediment on the corresponding levels in their tissue. Animals were collected from six sampling sites influenced by a wide range of surface water and stream sediment trace element concentrations. The results of the chemical analyses showed that tadpoles accumulated significant levels of all of the examined metals. The range of whole-body mean measured concentrations were (in dry mass) as follows: Cu (46-182?mg/kg), Pb (103-4,490?mg/kg), Zn (494-11,460?mg/kg), Mn (1,620-13,310?mg/kg), Cd (1.2-82?mg/kg), Ni (57-163?mg/kg), and Cr (38-272?mg/kg). The mean concentrations of Pb, Zn, Mn, Ni, Cr, and Cd in Kokkinolakkas stream, which drains a currently active mining area, were the highest ever reported in tadpoles. Our results indicate that whole-body levels of Pb, Zn, Cu, and Cd increase with stream sediment concentrations and that these organisms tend to accumulate metals bound to Fe and Mn oxides. In addition, high dissolved concentrations and significant concentrations associated with more labile geochemical phases of sediments for specific metals were contributing factors determining whole-body levels. Given the observed bioconcentration factors, as well as the correlation with sediment concentrations, it is proposed that these organisms could be considered as bioindicators of environmental contamination and may be used for monitoring purposes within this metal-rich zone and, perhaps, within other rivers affected by metal mining.     

Redistribution of Fractions of Zinc,Cadmium, Nickel,Copper, and Lead in Contaminated Calcareous Soils Treated with EDTA

Effect of ethylene diamine tetraacetic acid (EDTA) on the fractionation of zinc (Zn), cadmium (Cd), nickel (Ni), copper (Cu), and lead (Pb) in contaminated calcareous soils was investigated. Soil samples containing variable levels of contamination, from 105.9 to 5803 mg/kg Zn, from 2.2 to 1361 mg/kg Cd, from 31 to 64.0 mg/kg Ni, from 24 to 84 mg/kg Cu, and from 109 to 24,850 mg/kg Pb, were subjected to EDTA treatment at different dosages of 0, 1.0, and 2.0 g/kg. Metals in the incubated soils were fractionated after 5 months by a sequential extraction procedure, in which the metal fractions were experimentally defined as exchangeable (EXCH), carbonate (CARB), Mn oxide (MNO), Fe oxide (FEO), organic matter (OM), and residual (RES) fractions. In contaminated soils without EDTA addition, Zn, Ni, Cu, and Pb were predominately present in the RES fraction, up to 60.0%, 32.3%, 41.1%, and 36.8%, respectively. In general, with the EDTA addition, the EXCH and CARB fractions of these metals increased dramatically while the OM fraction decreased. The Zn, Ni, Cu, and Pb were distributed mostly in RES, OM, FEO, and CARB fractions in contaminated soils, but Cd was found predominately in the CARB, MNO, and RES fractions. The OM fraction decreased with increasing amounts of EDTA. In the contaminated soils, EDTA removed some Pb, Zn, Cu, and Ni from MNO, FEO, and OM fractions and redistributed them into CARB and EXCH fractions. Based on the relative percent in the EXCH and CARB fractions, the order of solubility was Cd > Pb > Ni > Cu > Zn for contaminated soils, before adding of EDTA, and after adding of EDTA, the order of solubility was Pb > Cd > Zn > Ni > Cu. The risk of groundwater contamination will increase after applying EDTA and it needed to be used very carefully.     

Toxic Element Concentration in the Atlantic Gannet Morus bassanus (Pelecaniformes, Sulidae) in Portugal

The present study provides the first data on inorganic element levels in juvenile, subadult, and adult Atlantic gannets (Morus bassanus). Physiological and potentially toxic elements (As, Cd, Co, Cr, Cu, Hg, Mn, Pb, Se, and Zn) were assessed by ICP-MS in kidney, liver, muscle, and feathers of 31 gannets, including 18 juveniles, 7 subadults, and 6 adults. The effect of age and tissue on element accumulation was also assessed. Mercury was roughly above the minimum level for adverse effects in birds. A higher accumulation of Se and Cd was detected in kidney, Pb in feathers, and Mn in liver. Age was found to affect the accumulation of Cd, Co, Hg, Mn, Se, and Zn. Adults presented significantly lower levels of Mn, Se, and Zn than subadults. Linear positive relationships within tissues were detected involving Se-Cd and Se-Hg. Also, positive linear relationships were detected among kidney, liver, and muscle, with emphasis on relationships involving Cd, Hg, Se, and Zn, which may be indicative of analogous regulation mechanisms in those organs. Atlantic gannets occurring in the study area leave their reproduction sites as juveniles. During their development process, several molting cycles occur and thus the possible contamination risk by Hg should reflect levels in the development areas rather than contamination levels in reproduction areas. The present study provides basic information on multielement accumulation in Morus bassanus, which may help us to understand the behavior and toxicity of various elements in marine birds.     

北京市居民饮用水中16种金属元素暴露水平

目的了解北京市居民饮用水中16种金属元素(铅Pb、镉Cd、铜Cu、锌Zn、铁Fe、锰Mn、镍Ni、银Ag、锑Sb、硒Se、铝Al、钡Ba、铍Be、铊Tl、钼Mo和钠Na)暴露水平。方法采用多阶段整群抽样设计,在北京市18个区县随机抽取5个区的270户,采用电感耦合等离子体质谱法,对枯水期、丰水期居民饮用水中16种金属指标进行监测。结果居民饮用水中16种元素的暴露水平由低到高可以分为3层:Ag、Cd、Sb、Be和Tl暴露水平为:未检出～0.083μg/L,Mo、Pb、Ni和Se暴露水平为:0.06～100μg/L,Cu、Al、Zn、Mn、Fe、Na和Ba暴露水平为:0.00036～6.579mg/L。统计表明,11种元素(Pb、Se、Mo、Cu、Zn、Mn、Ni、Al、Ba、Fe和Na)暴露水平枯水期明显高于丰水期(P<0.05),以《生活饮用水卫生标准》GB5749—2006中的标准值为评价标准,枯水期Na、Al、Mn、Zn、Fe、Ba、Pb、Se的合格率为87.4%～98.9%;丰水期Mn、Ni、Zn、Fe、Pb和Se的合格率为95.2%～99.6%,其他元素合格率为100%。来自市政水源的饮用水中8种元素(Pb、Cu、Zn、Mn、Al、Ba、Fe和Na)的暴露水平明显低于来自自备水源的饮用水(P<0.05)。结论北京市居民饮用水中16种金属元素总体处于低暴露水平,大部分指标市政供水好于自备水源供水。     

Assessment of Metals Pollution on Agricultural Soil Surrounding a Lead–Zinc Mining Area in the Karst Region of Guangxi, China

Soil samples were collected on farmland in a lead-zinc mining area in the Karst region of Guangxi, China. The contamination of the soil by eight metals (Cd, Hg, As, Cu, Pb, Cr, Zn, Ni) was determined. Among all these metals, Cd is the most serious pollutant in this area. Zn, Hg as well asPb can also be measured at high levels, which may affect the crop production. All other metals contributed marginally to the overall soil contamination. Besides the evaluation of single metals, the Nemerow synthetic index indicated that the soil is not suitable for agricultural use.