Sources and pathways of environmental lead to children in a Derbyshire mining village

Garden soil and housedust samples, from households in a Derbyshire village closely associated with historic lead mining, have highly elevated lead levels. Handwipe samples from children also have relatively high lead concentrations suggesting that elevated levels of lead are transferred to the child by the soil-dust-hand-mouth pathway. However, this is not reflected in their blood lead concentrations which are within normal UK ranges and less than predicted by some lead exposure models. SEM analysis of soil grains has revealed that many are composed of pyromorphite [Pb₅(PO₄)₃Cl], a stable soil-lead mineral. This mineral is formed from the weathering of galena [PbS] but it is not clear to what extent weathering has occurred in the soil. Pyromorphite has an extremely low solubility which may contribute to a low human bioavailability of lead in these soils, resulting in the lower than expected blood lead concentrations.     

Antimony speciation and contamination of waters in the Xikuangshan antimony mining and smelting area,China

Water samples from Xikuangshan (China), the world largest antimony (Sb) mine with a Sb mining and smelting history of more than 200 years, were analyzed. These water samples ranged from stream water in the vicinity of the mining and smelting area that received seepage from ore residues to the underground mine-pit drainage. The concentrations of total Sb, Sb (III) and Sb (V) of the samples were determined by HPLC-ICP-MS. In addition, water pH and concentrations of major cations and anions were analyzed. All 18 samples demonstrated total Sb concentrations with ppm levels from 0.33 ppm to 11.4 ppm, which is two to three orders of magnitude higher compared to the typical concentration of dissolved Sb in unpolluted rivers (less than 1 ppb). This is probably the first time that such high Sb contents have been documented with complete environmental information. Distribution of total Sb and Sb species was investigated, taking into account the respective local environment (in the mining area or close to the smelter, etc.). Sb (V) was the predominant valence in all 18 samples. Only trace levels of Sb (III) were detected in 4 of the 18 samples. Geochemical speciation modeling showed the dominant species was Sb(OH)₆⁻. It is also probably the first time that such high Sb contents have been documented in the natural environment with Sb speciation distribution information. Several potential oxidation pathways are also discussed that might have facilitated the oxidation of Sb (III) in the natural environment. Signs of intoxication were observed among local mine workers with extensive exposure to different forms of Sb for a long period of time.     

Urban Geochemistry: A Multimedia and Multielement Survey of a Small Town in Northern Europe

The concentrations and distributions of chemical elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti, Tl, U, V, W and Zn) were studied in till, humus and urban soil in Jakobstad, a small town (20,000 inhabitants) in W. Finland. The analyses were performed with ICP-MS after aqua regia leaching of till (n = 37), urban topsoil (n = 32) and subsoil (n = 32), and HNO3 leaching of humus (n = 37). The till and humus samples, collected at the same sites, were divided into urban and rural samples. The urban till was not significantly enriched in metals. In contrast, a majority of the elements occurred in higher concentrations in the urban than the rural humus samples. Statistical and spatial interpretations of the humus data revealed that traffic (Pb, V and Ni), metal industry (Pb, Zn, Bi, Sb and Cr), an abandoned shooting range (Pb and Sb) and other sources contribute to higher metal levels in the urban humus. The urban soil samples were collected at parks, yards, abandoned industrial sites, roadsides, etc. The topsoil samples were enriched in most elements, also by elements not enriched in the urban humus (e.g. Cd). At several sites, the concentrations far exceeded the limit concentrations for contaminated soils in Finland. A large variety of sources were identified or indicated.     

Natural and synthesised iron-rich amendments for As and Pb immobilisation in agricultural soil

The immobilisation of heavy metals in contaminated soils is a promising alternative to conventional remediation techniques. Very few studies have focused on the use of iron-rich nanomaterials and natural materials for the adsorption of toxic metals in soils. Synthesised iron-rich nanomaterials (Fe and Zr–Fe oxides) and natural iron-rich materials (natural red earth; NRE) were used to immobilise As and Pb in contaminated agricultural soil. Total concentrations of As and Pb in the initial soil (as control) were 170.76 and 1945.11 mg kg^?1, respectively. Amendments were applied into the soil at 1, 2.5 and 5% (w/w) in triplicate and incubated for 150 days. Except for the NRE-amended soil, soil pH decreased from 5.6 to 4.9 with increasing application rates of Fe and Zr–Fe oxides. With addition of Fe and Zr–Fe oxides at 5%, the ammonium acetate (NHO₄Ac)-extractable Pb was greatly decreased by 83 and 65% compared with NRE addition (43%). All subjected amendments also led to a decrease in NHO₄Ac-extractable As in the soils, indicating the high capacity of As immobilisation. Soil amended with NRE showed a lower ratio of cy19:0 to 18:1ω7c, indicating decreased microbial stress. The toxicity characteristic leaching procedure produced results similar to the NHO₄Ac extraction for As and Pb. The NRE addition is recommended for immobilising heavy metals and maintaining biological soil properties.     

Tissue distribution of antimony (Sb) in piglets orally given graded levels of Sb (V)

The potential risks from oral intake of soil antimony (Sb) depends mainly on the amount of metal ingested and its bioavailability. Relative bioavailability may be determined by comparing Sb present in soil to a reference compound, taking into account accumulation in different target tissues or excretion. However, due to the lack of scientific knowledge concerning the fate of Sb in the organism, there is a need to study the absorption and distribution of Sb in order to select target tissues for assessment of bioavailability of Sb in soils. Thus, 45 piglets were exposed to a soluble pentavalent antimony salt (KSb(OH)₆), for 15 days at concentrations ranging from 0–1600 µg Sb/kg body weight (BW) per day. Following the exposure period, blood, plasma, liver, spleen, kidneys, hair, bone, bile and urine were obtained to measure Sb concentrations by ICP-MS. Results showed that tissue Sb levels were dose-related. Higher Sb concentrations were found in urine, kidneys, hair, bone and liver. Sb(V) was not detectable in blood and plasma. In the case of highly contaminated soil with soluble forms of Sb in concentrations ranging from 200–1600 µg Sb/kg BW, kidneys, liver and spleen are the most reliable compartments to determine Sb bioavailability from soil. However, for the soils with lower levels of contamination and a low Sb bioaccessibility, urine may serve as a relevant compartment.     

The selenium status of sheep in Britain as indicated by wool selenium concentration

A correlation between the selenium concentration in wool and blood erythrocyte glutathione peroxidase activity (GSHPx) from sheep in W. Derbyshire, a high selenium area and N. Wales and Romney Marsh, low/marginal selenium areas is reported.Soil and herbage selenium concentrations were significantly correlated with wool selenium levels and GSHPx activity.A significant difference was found between wool selenium concentrations and between GSHPx activities from sheep in W. Derbyshire and those animals sampled in N. Wales and Romney Marsh. 90% of wool samples from the low/marginal areas gave concentrations below 0.125 g Se/g. 6.125 g Se/g wool is suggested as a threshold value for selenium in wool from sheep grazing low/marginal areas.Seasonal peaks in wool selenium concentrations and GSHPx activities are found in March and June respectively. Supplementary feeds, which contain added selenium, given to livestock during the winter season may be responsible for these seasonal differences.GSHPx activity data reported in this study records higher sheep selenium levels than those reported in the 1979 survey by Andersonet al. This increase is attributed to the addition since 1979 of selenium to feeds and drenches.Wool is proposed as an accurate and less costly measure of sheep selenium status.     

Preliminary observations on the effect of heavy metals from mining and smelting on nitrogen-fixing bacteria in some British soils

Nitrogen fixation by free-living non-symbiotic bacteria has been qualitatively estimated in several surface soils and mine wastes from mineralised areas in Derbyshire and Cornwall, using a technique based on acetylene reduction. Fresh samples contaminated with varying amounts of one or more of the metals lead, zinc, cadmium and copper, together with appropriate controls, showed no ability to reduce acetylene, indicating an absence of nitrogen fixation. Addition of activeAzotobacter chroococcum resulted in acetylene reduction in the majority but not all of the samples. The effects of varying concentrations of lead, zinc, cadmium and copper on the growth ofAzotobacter chroococcum andBeijerinckia lactogenes were tested in laboratory culture.     

Natural concentrations and reference values for trace elements in soils of a tropical volcanic archipelago

Fernando de Noronha is a small volcanic archipelago in the Southern Atlantic, some 350 km NE of the city of Natal in NE Brazil. These remote volcanic islands represent a largely pristine environment, distant from sources of anthropogenic contamination. This study was carried out to determine the natural concentrations of Ag, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, V and Zn in the A and B horizons of soils of Fernando de Noronha. The aims of the study were twofold: determine whether there is a relationship between the bedrock geology and soils and to establish quality reference values for soils from Fernando de Noronha. Soil samples were subjected to acid digestion by the USEPA method 3051A, and metals were determined by inductively coupled plasma emission spectrophotometry. The results showed that the trace element distribution largely reflects the geochemistry of the underlying volcanic rocks of the Remedios and Quixaba Formations. The results demonstrate that the concentrations of Ba, Cr, Zn, Ni and Cu from the soils of the volcanic Fernando de Noronha archipelago are higher than those found in soils from continental Brazil. However, concentrations of Ni, Cu and Co are lower in soils of the archipelago as compared to other volcanic islands throughout the world. The elevated trace element concentrations of the volcanic parent material of Fernando de Noronha soils seem to be the main factor governing the relatively high natural concentrations of trace elements.     

Distribution and phytoavailability of antimony at an antimony mining and smelting area,Hunan, China

An investigation of the distribution, fractionation and phytoavailability of antimony (Sb) and other heavy metals in soil sampled at various locations in the vicinity of a Sb mine revealed elevated levels of Sb, most certainly due to the mining activities. The concentration of Sb in the soil samples was 100.6–5045 mg kg⁻¹; in comparison, the maximum permissible concentration for Sb in soil in The Netherlands is 3.5 mg kg⁻¹, and the maximum permissible concentration of pollutant Sb in receiving soils recommended by the World Health Organization is 36 mg kg⁻¹. The soil sampled near the Sb mine areas had also contained high concentrations of As and Hg. Root and leaf samples from plants growing in the Sb mine area contained high concentrations of Sb, with the concentration of Sb in the leaves of radish positively correlating with Sb concentrations in soil. The distribution of Sb in the soil showed the following order: strongly bound to the crystalline matrix > adsorbed on Fe/Mn hydrous oxides, complexed to organic/sulfides, bound to carbonates > weakly bound and soluble. Solvents showed varying levels of effectiveness in extracting Sb (based on concentration) from the soil, with , in decreasing order. The concentration of easily phytoavailable Sb was high and varied from 2.5 to 13.2 mg kg⁻¹, the percentage of moderately phytoavailable Sb ranged from 1.62 to 8.26%, and the not phytoavailable fraction represented 88.2–97.9% of total Sb in soils.     

废弃铅锌冶炼厂重金属污染场地的健康风险评价

通过对广西某废弃铅锌冶炼厂区进行布点采样、监测分析,选取Cu、Pb、Zn、Cd、Cr、As六种重金属元素作为评价因子,对污染场地进行健康风险评价.结果显示,指数评价法表明厂区污染状况为废渣＞＞建筑垃圾＞土壤,Cd ＞Zn ＞As ＞Pb ＞Cu＞ Cr,土壤受到中度污染,废渣和建筑垃圾受到重度污染.健康风险评价法表明土壤、废渣和建筑垃圾的危害商分别为2.032、13.891、2.975,非致癌危害废渣＞＞建筑垃圾＞土壤;Cu、Zn、Cr、Cd、As的危害商分别为0.053、0.118、0.184、7.001、11.542,非致癌危害As ＞Cd ＞Cr＞Zn ＞Cu.土壤、废渣和建筑垃圾的致癌风险分别为5.387E-04、7.954E-04、2.455E-04,致癌危害废渣＞土壤＞建筑垃圾;As、Cd、Cr的致癌风险分别为5233E-04、2.400E-05、1.032E-03,致癌危害Cr＞As ＞Cd.综上,人体健康危害废渣＞建筑垃圾＞土壤,主要危害元素为As、Cd、Cr.     

Metals and metalloids in PM10 in Nandan County,Guangxi, China,and the health risks posed

Intense mining, smelting, and tailing activities of polymetallic ore deposits have affected the environment in Nandan County, Guangxi, China. Samples of particulates with aerodynamic diameters low or equal 10 μm (PM₁₀) were collected in Nandan County to investigate the concentrations of and health risks posed by 17 metals and metalloids in the PM₁₀. The metal and metalloid concentrations were lower than those found in other industrial cities. The mean Cr concentration was 7.48 ng/m³. Significant higher metal and metalloid concentrations were found in PM₁₀ from mining areas (Dachang and Chehe) than from the control area (Liuzhai) (p < 0.05). Principal component analysis indicated that the main sources of Ba, Co, Cr, Fe, K, Mg, Mo, Na, and Sr were resuspension of the soil produced through mineral erosion, the main sources of As, Cd, Cu, Pb, Sb, and Zn were smelting and mining activities, and the main source of Ni was fossil fuel combustion. Higher non-carcinogenic and carcinogenic risks were posed in Dachang and Chehe than in Liuzhai. The non-carcinogenic risks posed to adults and children by individual metals and metalloids in PM₁₀ at all the sites were low, but the non-carcinogenic risks posed to children by all the metals and metalloids together exceeded the safe level (i.e., risk value > 1). The carcinogenic risks posed by Cd, Ni, and Pb were negligible at all sites, while As, Co, and Cr posed potential carcinogenic risks to the residents.

     

Assessment of bioaccessibility and exposure risk of arsenic and lead in urban soils of Guangzhou City,China

Soil ingestion is an important human exposure pathway of heavy metals in urban environments with heavy metal contaminated soils. This study aims to assess potential health risks of heavy metals in soils sampled from an urban environment where high frequency of human exposure may be present. A bioaccessibility test is used, which is an in vitro gastrointestinal (IVG) test of soluble metals under simulated physiological conditions of the human digestion system. Soil samples for assessing the oral bioaccessibility of arsenic (As) and lead (Pb) were collected from a diverse range of different land uses, including urban parks, roadsides, industrial sites and residential areas in Guangzhou City, China. The soil samples contained a wide range of total As (10.2 to 61.0 mg kg⁻¹) and Pb (38.4 to 348 mg kg⁻¹) concentrations. The bioaccessibility of As and Pb in the soil samples were 11.3 and 39.1% in the stomach phase, and 1.9 and 6.9% in the intestinal phase, respectively. The As and Pb bioaccessibility in the small intestinal phase was significantly lower than those in the gastric phase. Arsenic bioaccessibility was closely influenced by soil pH and organic matter content (r ² = 0.451, p < 0.01) in the stomach phase, and by organic matter, silt and total As contents (r ² = 0.604, p < 0.001) in the intestinal phase. The general risk of As and Pb intake for children from incidental ingestion of soils is low, compared to their maximum doses, without causing negative human health effects. The exposure risk of Pb in the soils ranked in the order of: industrial area/urban parks > residential area/road side. Although the risk of heavy metal exposure from direct ingestion of urban soils is relatively low, the risk of inhalation of fine soil particulates in the air remains to be evaluated.     

Health risk estimates for groundwater and soil contamination in the Slovak Republic: a convenient tool for identification and mapping of risk areas

We undertook a quantitative estimation of health risks to residents living in the Slovak Republic and exposed to contaminated groundwater (ingestion by adult population) and/or soils (ingestion by adult and child population). Potential risk areas were mapped to give a visual presentation at basic administrative units of the country (municipalities, districts, regions) for easy discussion with policy and decision-makers. The health risk estimates were calculated by US EPA methods, applying threshold values for chronic risk and non-threshold values for cancer risk. The potential health risk was evaluated for As, Ba, Cd, Cu, F, Hg, Mn, NO₃ ^?, Pb, Sb, Se and Zn for groundwater and As, B, Ba, Be, Cd, Cu, F, Hg, Mn, Mo, Ni, Pb, Sb, Se and Zn for soils. An increased health risk was identified mainly in historical mining areas highly contaminated by geogenic–anthropogenic sources (ore deposit occurrence, mining, metallurgy). Arsenic and antimony were the most significant elements in relation to health risks from groundwater and soil contamination in the Slovak Republic contributing a significant part of total chronic risk levels. Health risk estimation for soil contamination has highlighted the significance of exposure through soil ingestion in children. Increased cancer risks from groundwater and soil contamination by arsenic were noted in several municipalities and districts throughout the country in areas with significantly high arsenic levels in the environment. This approach to health risk estimations and visualization represents a fast, clear and convenient tool for delineation of risk areas at national and local levels.     

Arsenic (As), antimony (Sb), and lead (Pb) availability from Au-mine Technosols: a case study of transfer to natural vegetation cover in temperate climates

Soils from old Au-mine tailings (La Petite Faye, France) were investigated in relation to the natural vegetation cover to evaluate the risk of metals and metalloids (Pb, As, Sb) mobilizing and their potential transfer to native plants (Graminea, Betula pendula, Pteridium aquilinum, Equisetum telmateia). The soils are classified as Technosols with high contamination levels of As, Pb, and Sb. The single selective extractions tested to evaluate available fraction (CaCl₂, acetic acid, A-Rhizo, and DTPA) showed low labile fractions (<5 % of bulk soil contents), but still significant levels were observed (up to 342.6 and 391.9 mg/kg for As and Pb, respectively) due to the high contamination levels of soils. Even at high soil contaminations (considered as phytotoxic levels for plants), translocation factors for native plants studied are very low resulting in low concentrations of As, Sb, and Pb in their aerial part tissues. This study demonstrates the important role of (1) native plant cover in terms of “stabilization” of these contaminants, and (2) the poor effectiveness of extraction procedures used for this type of soil assemblages, i.e., rich in specific mineral phases.     

Investigation of correlativity between heavy metals concentration in indigenous plants and combined pollution soils

The accumulation of heavy metals (HMs) in soils is potentially hazardous to human, livestock and plant species. HMs in the combined pollution soils and indigenous plants were investigated in a non-ferrous metal-smelting area. The purpose of this study was to determine the HMs in the contaminated soil and different plant species found growing on it, as well as calculation of bioaccumulation coefficients (BACs). Representative sampling sites were identified according to the land-use types. A total of 12 surface soil samples and 32 plant samples were collected. HMs were analysed by inductively coupled plasma mass spectrometry. The levels of soil pollution were assessed using Nemerow’s synthetical contamination index method. The synthetical index was in the range of 16.81–198.11. This result indicated a heavy burden on local environment. HM concentrations in plants were directly related with soil concentrations. The average BACs of five metals were found in the order of Cd (0.309)?>?Zn (0.178)?≈?Pb (0.160)?>?Cu (0.105)?>?Sb (0.0672). Spontaneous weeds including Chenopodium album Linn, Kochia scoparia and trees of Leuce, Ulmus pumila were deemed HM accumulators. The results provided a practical basis for phytoremediation of HM-contaminated soils using accumulator species.     

Chemical availability of arsenic and antimony in industrial soils

Total concentrations and extractable fractionations of As and Sb were determined in soil samples from former mining sites in Scotland and Italy. Pseudo-total levels of As and Sb in the sample were between 50–17,428 mg/kg and 10–1,187 mg/kg (Scotland), and 16–691 mg/kg and 1.63–11.44 mg/kg (Italy). Between 0.001–0.63% and <0.001−8.82% of the total soil As and Sb, were extractable using, a single extraction bioavailability estimate. Data from an As-specific extraction procedure revealed that up to 60% of As was associated to amorphous Fe-Al oxyhydroxide phase in all soils. A non-specific-sequential extraction test also showed As to be strongly associated with Fe (and Al) oxyhydroxides at both locations. In the case of Sb, in addition to the crystalline Fe-oxide bound Sb the Al-silicate phase also appeared to be significant. At both sites Sb appears to be chemically more accessible than As with consistent availability despite the varied origin and host soil properties.     

南京城市土壤重金属含量及空间分布特征

研究了南京城市土壤重金属含量、来源及空间分布特征。结果表明,南京城市土壤中V、Mn、Co、Ni、Cr污染不明显,但受到了不同程度的Cu、Pb、Zn、Sb、Hg、Cd污染,其中Hg污染比较严重。V、Mn、Co、Ni、Cr含量之间均呈极显著正相父;Cu、Pb、Zn、Sb、Hg、Cd含量之间也均呈极显著正相关。南京城市土壤V、Mn、Co、Ni、Cr主要继承了原土物质;Hg、Cd、Pb主要来源于城市燃煤、机动车尾气及工厂排放粉尘;Sb主要来源于机动车尾气和工厂排放粉尘。南京城市土壤Hg、Cd、Pb、Sb含量空间分布规律非常相似,均表现为外围向市中心有逐渐增加的趋势,并且在新街口—鼓楼、梅山硫铁矿形成异常高值的岛状、环状区域。     

Heavy metal migration in soils and rocks at historical smelting sites

The vertical migration of metals through soils and rocks was investigated at five historical lead smelting sites ranging in age between 220 and 1900 years. Core samples were taken through metal-contaminated soils and the underlying strata. Concentration profiles of lead and zinc are presented from which values for the distances and rates of migration have been derived. Slag-rich soil horizons contain highly elevated metal concentrations and some contamination of underlying strata has occurred at all sites. However, the amounts of lead and zinc that have migrated from soils and been retained at greater depths are comparatively low. This low metal mobility in contaminated soils is partly attributed to the elevation of soil pH by the presence of calcium and carbonate originating from slag wastes and perhaps gangue minerals. Distances and rates of vertical migration were higher at those sites with soils underlain by sandstone than at those with soils underlain by clay. For sites with the same parent material, metal mobility appears to be increased at lower soil pH. The mean migration rates for lead and zinc reach maxima of 0.75 and 0.46 cm yr^–1 respectively in sandstone at Bole A where the elements have moved mean distances of 4.3 and 2.6 m respectively. There is some evidence that metal transport in the sandstone underlying Bole A and Cupola B occurs preferentially along rock fractures. The migration of lead and zinc is attenuated by subsurface clays leading to relatively low mean migration rates which range from 0.03 to 0.31 cm yr^–1 with many values typical of migration solely by diffusion. However, enhanced metal migration in clays at Cupola A suggest a preferential transport mechanism possibly in cracks or biopores.     

Is there a relationship between soil and groundwater toxicity?

Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.     

Heavy metal contamination of soils at old mining sites on Thasos Island,Greece

Thasos Island has a long history of metalliferous mining, the first mining activities having been initiated by the Phoenicians during the seventh century. The mineralogy of the mineralisation includes primary minerals (galena, sphalerite) and secondary oxidised minerals (smithsonite, cerussite). In the soils studied only secondary minerals were found. Clay minerals (kaolinite, illite, montmorillonite, mixed layer clays), plagioclase, calcite and dolomite are also present in the soils. Contamination derived from the old mining sites results in extremely high levels of Pb, Zn, Mn, Fe, As, Sb, Ag, Cd in soils in the vicinity of the old workings. Since many of the Thasos mining sites are in, or adjacent to, areas of agricultural land, plants growing on the polluted sous have increased concentrations of heavy metals. This may well have a possible effect on livestock.