A column leaching study, coupled with acid deposition simulation, was conducted to investigate the leaching of potentially toxic metals (PTM) from zinc smelting slag materials (SSM) after being incubated in an acid Alfisol for 120 days at room temperature. Two SSMs (SSM-A: acidic, 10 yrs exposure with moderate high PTM concentrations versus SSM-B: alkaline, 2 yrs exposure with extremely high PTM concentrations), were used for the incubation at 0.5, 1, 2.5, 5 wt% amendment ratios in triplicate. Five leaching events were conducted at day 1, 3, 7, 14, and 28, and the leaching of PTMs mainly occurred in the first three leaching events, with the highest PTM concentrations in leachate measured from 5 wt% SSM amendments. After leaching, 2.5, 12, 5.5, 14, 11, and 9 wt% of M3 extractable Pb, Zn, Cd, Co, Cr, and Ni could be released from 5 wt% SSM-A amended soils, being respectively 25, 12, 4, 2, 2, and 2 times more than those from 5 wt% SSM-B amended soils. In the leachates, the concentrations of PTMs were mostly affected by leachant pH and were closely correlated to the concentrations of Fe, Al, Ca, Mg and P with Cd, Pb, and Zn showing the most environmental concern. Visual MINTEQ 3.1 modeling suggested metallic ions and sulfate forms as the common chemical species of PTMs in the leachates; whereas, organic bound species showed importance for Cd, Pb, Cu, and Ni, and CdCl+ was observed for Cd. Aluminum hydroxy, phosphate, and sulfate minerals prevailed as the saturated minerals, followed by chloropyromorphite (Pb5(PO4)3Cl) and plumbogummite (PbAl3(PO4)2(OH)5·H2O) in the leachates. This study suggested that incubation of SSMs in acidic soil for a long term can enhance the release of PTMs as the forms of metallic ions and sulfate when subjected to acid deposition leaching.

Over the past few decades, zinc smelting activities in Guizhou, China have produced numerous slag dumps, which are often dispersed on roadsides and hill slopes throughout the region. During periods of acid rain, these exposed slags release heavy metals into surface water bodies. A column leaching study was designed to test the potential release of the heavy metals cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) under simulated acid rain events. Two slags with varying environmental exposure periods were packed in columns and subjected to leaching solutions of pH 3.5, 5.5, or DI H2O at intervals of 1, 7, 14, 28, 56d. Pulse concentrations of Cd in leachate were found above 5μg/L, Cr, Pb, and Zn >10μg/L, whereas, Cu reached 10μg/L. After five leaching events, the leachability (percentage of cumulative heavy metal leached after five leaching events as in its respective total concentration in slags) of Cd was 0.05 percent and 0.035 percent from the old and young slag, respectively. Cr (0.035 percent and 0.05 percent) was greater than Cu (0.002 percent and 0.005 percent) and Zn (0.006 percent and 0.003 percent), while the lowest leachability was observed for Pb (0.0005 percent and 0.0002 percent) from the old and young slags, respectively. Reaction rates (release amount of heavy metals in certain period of leaching) of heavy metals in the leachates demonstrated the sequence of Zn>Cr>Cd, Cu>Pb. Leaching release of heavy metals was jointly affected by the pH of leaching solution and mineral composition of slags (including chemical forms of Cd, Cr, Cu, Pb, and Zn). Environmental exposure period of slags, resulting in the alteration of minerals, could affect the release process of heavy metals in leaching as well.

Lead, Zn, and Cd in vegetables/crops were investigated in a zinc smelting region in China, and their daily dietary intake by local residents was estimated. It is observed that Pb, Zn, and Cd were in 34.7–91.1, 242–575, and 0.199–2.23 μg g−1 dry weight in vegetables/crops with their greatest concentrations in leafy vegetable. The daily dietary intake of Pb, Zn, and Cd by adult residents reached 3, 646, 59,295, and 186 μg day, respectively, and lettuce and cabbage together contributed 75% of the Pb, 50% of the Zn, and 70% of the Cd.

The geochemical characteristics of the hot spring waters in the Rehai and Ruidian geothermal fields, Teng-chong County, Yunnan Province, China, were described and their possible environmental impact was assessed. The results show that the alkaline spring waters contain high levels of K, Na, F, Cl, and SiO_2, whereas the only acidic spring water in Rehai geothermal field contains high levels of SO_4~(2-), Mn and Fe. As and Sb in the spring waters are in the ranges of 43. 6-687 μg/L and 0. 38-23. 8 μg/L, respectively. As (Ⅲ) occur s in most spring waters, and thefraction of As( Ⅲ) is up to 91% of total As. Fractions of geothermal As and Sb are trapped in the sinter deposits while most of them enter the environment The diffusion of As and Sb into groundwater and downstreams in crop fields constitutes a threat to the health of the local population.

Dust emissions from smelters, as a major contributor to heavy metal contamination in soils, could severely influence soil quality. Downwind surface soils within 1.5 km of a zinc smelter, which was active for 10 years but ceased in 2000, in Magu Town, Guizhou Province, China were selected to examine Pb, Zn, and Cd concentrations and their fractionation along a distance gradient from a zinc smelter, and to study the possible effects of Pb, Zn, and Cd accumulation on soil microorganisms by comparing with a reference soil located at a downwind distance of 10 km from the zinc smelter. Soils within 1.5 km of the zinc smelter accumulated high levels of heavy metals Zn (508 mg kg−1), Pb (95.6 mg kg−1), and Cd (5.98 mg kg−1) with low ratios of Zn/Cd (59.1–115) and Pb/Cd (12.4–23.4). Composite pollution indices (CPIs) of surface soils (2.52–15.2) were 3 to 13 times higher than the reference soils. In metal accumulated soils, exchangeable plus carbonate-bound fractions accounted for more than 10% of the total Zn, Pb, and Cd. The saturation degree of metals (SDM) in soils within 1.5 km of the smelter (averaging 1.25) was six times higher than that of the reference soils (0.209). A smaller soil microbial biomass was found more frequently in metal accumulated soils (85.1–438 μg C g−1)thanin reference soils (497 μg C g−1), and a negative correlation (P< 0.01) of soil microbial biomass carbon to organic carbon ratio (Cmic/Corg) with SDM was observed. Microbial consumption of carbon sources was more rapid in contaminated soils than in reference soils, and a shift in the substrate utilization pattern was apparent and was negatively correlated with SDM (R = −0.773, P< 0.01). Consequently, dust deposited Pb, Zn, and Cd in soils from zinc smelting were readily mobilized, and were detrimental to soil quality mainly in respect of microbial biomass.

Laowanchang gold deposit, located in Qinglong County, Guizhou Province. Southwest China, is the first-discovered laterite type gold deposit in Guizhou Province. Although most scholars are inclined to agree that ore-forming substance was closely correlated with "Dachangceng layer", it still remained controversial. Former researchers did not find existences of visible Au grains in limonite. clay minerals or pyrite under SEM observation: therefore, they considered Au occurrence mainly as micro-disseminated form.In this study, mineral composition, chemical components and chemical index of alteration of laterites indicated that three chemical weathering processes, including argillaceous, bauxitic and ferric process can be observed in Laowanchang laterization. Geochemically, such laterization can be attributed to early laterization stage. Components of K(2)O, Na(2)O, and CaO were highly leached during weathering indicating a strong chemical alteration.Concentrations of ore-forming elements (Au, As and Sb)varied greatly along laterite profiles. Concentrations of Aut were usually in the range of 40x 10(-9)-4551 x 10(-9): As in 0.1-0.9% with the highest value of 1.8%; Sb < 0.1%. Concentrations of Au, As and Sb in laterites were obviously higher than in silicalites of Dachanceng layer. During laterization, enrichment of Au and As were obviously related with enrichment of Fe. Au and As enriched in relatively reductive locations, while Sb in the relatively oxidized circumstances,Rare earth element (REE) contents were higher in laterite profiles with LREE/HREE ratios usually less than 10. REE had very similar distribution patterns in laterites, significantly differing from those of Dachanceng layer. Features of trace element pairs (including large ionic lithophile elements and incompatible elements) and ore-forming element pairs diagramed great differently between laterites and Dachanceng layer. These phenomena supported that laterites would not directly be developed from Dachanceng layer rocks, but mainly be related with Quaternary sediments. Ore-forming substances of Laowanchang gold deposit also connected less with Dachancenglayer.Au occurrences in laterites varied under TEM-EDX observations. Gold existed either as granular natural gold, or adsorbed by goethite and As-bearing goethite. or by siliceous matter and quartz, sometimes by illites. Reduction of Au(3+) to Au(0+) by Fe(2+) played an important role in enrichment of Au during laterization. (C) 2008 Elsevier B.V. All rights reserved.

The authors have reviewed some advances of the research on the pollution of heavy metals to areas around lead/Zinc mines in the world in the last decade.The distribution,states,accumulation,migration and transformation of heavy metals in soils,plants,and water and atmosphere system,due to the development of lead-zinc mines in the world have been comprehensively studied in the last decade.The temporal and special distribution characters,bioavailability,and influencing factors and mechanisms of heavy metals in lead-zinc mining areas have been summarized,reviewed and briefly discussed by this paper in order to understand deeply and systematically and to propose some constructive suggestions for the further study.

矿山开发过程产生的废石、废渣、矿坑排水及冶炼尾矿和炉渣等都或多或少地含有重金属.在长期的风化淋滤作用过程中某些重金属元素就迁移释放出来,从而污染周围的土壤和水体.重金属在地表环境中不能被微生物降解,具有累积效应.生物体通过食物链富集重金属,并把重金属转化成毒性更强的化合物;重金属就因这种隐蔽性、长期性和不可逆性而影响人类健康.

The geochemical characteristics of the hot spring waters in the Rehai and Ruidian geothermal fields, Tengchong County, Yunnan Province, China, are described and their possible environmental impact assessed. The results show that the alkaline spring waters contain high levels of K, Na, F, Cl, SiO2, whereas the only acidic spring water in Rehai geothermal field contains high levels of SO42−, Mn and Fe. As and Sb in the spring waters are in the range 43.6–687 μg/L and 0.38–23.8 μg/L, respectively. As(III) occurs in most spring waters, and constitutes up to 91% of the total As. A fraction of the geothermal As and Sb is trapped in the sinter deposits while most enters the environment. The diffusion of As and Sb into groundwater and downstream crop fields constitutes a threat to the health of the local population.

Zhijin Xinhua phosphate deposits is an important marine sedimentary phosphate deposits formed in Early Cambrian Epoch located in South-west edge of Yangtze Platform.For decades,the mineral composition of phosphate in Zhijin Xinhua phosphate deposits is considered to be Carbonatefluorapatite or low-Carbonatefluorapatite.Some researchers believe that almost all of the apatite formed in sedimentary rocks belong to Carbonatefluorapatite.In our study,by using of the technique of electron probe microanalysis(EPMA) and X-ray diffraction,we found that the mineral composition of the clastic phosphate in Zhijin phosphate deposits is fluorapatite.This results may provide some useful information for the study of metallogenesis of the Zhijin Xinhua phosphate deposits.

The Aha Reservoir is the drinking water source of Guiyang City.The waste water from coal mines was the main pollution source in the Aha Reservoir before 1990's.Afterwards,mine waste water was dealt with,so much progress has been made in controlling mine waste water pollution.Domestic sewage was the main pollution source in the Aha Reservoir.The concentrations of total mercury are 7.1～47.9 ng/L,those of methylmercury are 0.16～2.5 ng/L,and those of reactive mercury are 0.25～2.43 ng/L.Discernible seasonal variation of those mercury species were obtained during the sampling periods.Mercury in Aha Reservoir rivers was mostly associated with particulate mercury,total mercury was evidently correlated to particulate mercury.Now,the levels of different mercury species in the only output river — the Xiaoche River are lower than those of input rivers.It is shown that the effects of deposition and purge in the Reservoir are properly obvious.

The contamination of lead in soil induced by local zinc smelting activities in Hezhang County,Guizhou Province was studied.The total lead amount in adjacent soil ranges from 71.8～37247.4 mg/kg,and tends to increase with the smelting history.Generally,contamination level of Pb decreased with distance from the smelting area,though this trend differs somewhat in different smelting areas.The vertical distribution of Pb in the soil profile showed that lead was mainly concentrated in top soil(0-20 cm),however,in deep layer soil(20-50 cm) lead also increased to some extent and the Pb content of subsoil increased with the smelting history.In addition,the chemical fractions of Pb were extracted by 0.01 mol·L-1 CaCl2 and 0.005 mol·L-1 DTPA,and the results showed that the CaCl2 extractable and DTPA extractable fractions were very low in percentage(0.3%,5%)of the total content,but its contents are up to 6.4～1037 mg/kg,and tend to increase with increasing accumulated time of Pb in the soil,but their percentages decreased with increasing accumulated time of Pb in the soil.

A survey of soils and four flourishing plants was carried out in the polluted sites by zinc smelting in northwestern Guizhou Province.The fractions of heavy metals in the soils were distinguished as mobile fraction and residual fraction by a short sequential extraction procedure.Heavy metal contents in the plants were found linearly increasing with their concentrations in soils around the plant rhizosphere.The concentrations of Pb,Zn and Cd in the four plants increase in the order Zn>Pb>Cd.Sambucus Chinensis and Ixeris gracilis were proved to have good metal-enriching and transport abilities,and these plants would be useful to recover the ecological environment in these heavy metal polluted regions.

Total heavy metal (Cd, Cr, Cu, Pb and Zn) concentrations were evaluated in smelting waste, soil, crop and moss samples collected from the Hezhang artisanal zinc smelting areas, Guizhou, China. Soil samples from the cornfield near the smelting sites contained extremely high Cd (5.8-74 mg kg(-1)), Pb (60-14,000 mg kg(-1)) and Zn (260-16,000 mg kg(-1)) concentrations. Elevated heavy metal concentrations were also found in corn plants and total Pb (0.80-1.5 mg kg(-1)) and Cd (0.05-0.76 mg kg(-1)) concentrations in corn grain have totally or partially exceeded the national guidance limits for foodstuff. Thus, the soil-to-crop transfer of heavy metals might pose a potential health risk to the local residents. Similar to the high heavy metal levels in soil and corn, Cd, Cr, Cu, Pb and Zn concentrations in moss samples collected from the smelting sites ranged from 10 to 110, 10 to 55, 26 to 51, 400 to 1200 and 330 to 1100 mg kg(-1), respectively, exhibiting a local spatial pattern of metals deposition from the atmosphere. Based on examination of Zn/Cd and Pb/Cd ratios of the analyzed samples, we have distinguished between the flue gas dust derived and smelting waste derived metals in different environmental compartments.

Erjia gold deposit, located in Hainan province, was closely related with Gezhen shear zone activity. In this paper, tectono-geochemical method and tectono-geochemical simulating experiments were applied to studying the relations of Gezhen shear zone activity and gold ore-forming process. Evidences show that dynamic deformation resulted in the deformation of migmatitic rock and the formation of mylonite, and in this process normally accompanied by tectonic fluid activity, variation in mineral compositions and chemical components can be observed. Several deformation mechanisms could be distinguished in the deformation of Gezhen shear zone, of which the resilience mechanism could benefit most for gold enrichment in mylonites. Differential paleogeometor from recrystallizied grain size of quartz testified a significant positive relation of deformation strength to Au enrichment; its correlation coefficient could be as high as +0.5928. Trace element abundances in quartz formed in different dynamic deformation stages varied greatly; chemical compounds of fluid inclusion formed in different stages also varied obviously, this indicates a closer relation between differentiations of tectonic fluid activity and gold enrichment. Results listed as follows could be observed in tectono-geochemical simulating experiments: texture of tested samples was altered due to dynamic deformation, micro-shear zone was formed where cataclastic grain flow and apparent fluid activity were accompanied. These phenomena are connected closely with pressure dissolution. Furthermore, gold enrichment and precipitation could be observed during deformation, and it is found that chemical elements Si and Fe played key roles in this process.

A series of tectono-geochemical experimental tests on block rock and powder samples were carried out by stimulating the dynamic condition of the Erjia gold deposit, Hainan Province and the Hetai gold deposit, Guangdong Province. Significant mechano-chemical coupling in dynamic deformation can be observed for block rock and powder samples after experiments. Mica minerals were strongly deformed, ductilely deformed and directionally elongated. Biotites were commonly discolored, usually from brown color to hazel color, even to colorlessness, while muscovites were discolored on their interference color, from bright blue to yellowish, even to colorlessness. With the elevation of test temperature and pressure, the rocks and minerals were deformed from brittleness to ductility. Dynamic deformation also caused chemical migration and enrichment of elements, especially Au, in the rocks and minerals, for example, impurity capacity in mica minerals was decreased, which induced the release of Fe; the reflectivity of sulfide minerals was elevated, which induced the variance of ore-forming elements in their different parts. Natural gold grains were observed crystallized and purified with separation from Si and Fe. The migration and enrichment of ore forming elements, especially Au, during dynamic deformation was controlled and effected by pressure solution process.

镉对环境和人体健康有巨大的危害,但煤中镉的含量一般远低于它在地壳中的丰度,所以人们对于煤中镉的关注程度较低.笔者在研究黔西南高砷煤的过程中,发现有镉矿物,这对于认识镉在成煤过程中的行为和燃煤可能造成的镉污染具有积极的意义.

Lamprophyres are widely spread over the Laowangzhai gold orefield in northern Mt. Ailao structure zone, Yunnan Province. Lampmphyres in the orefield are temporally and spatially related to gold mineralization. Lampmphyren in the orefield have anomalous Sr and Nd isotopic compositions, e.g. the 87 Sr/ 86 Sr ratios (0.706 665–0.707 960, the 87 Sr/ 86 Sr ratio of sample YLW-44 is 0.709 041) are higher than the modern value of the original mantle (0.704 5), the 143 Nd/ 144 Nd ration (0.512 463–0.512 551) are lower than the modern value of the original mantle (0.512 638), and the calculated values ε Sr > 0 (28.1–63.7) and ε Nd < 0 (- 1.34- -3.07). The results of investigation inete that lampmphyres in the Laowangzhai gold orefield with anomalous Sr and Nd isotopic compositions would not be produced as a result of contamination of the primary magma with the isotopic features of MORB by the crust materials high 87 Sr/ 86 Sr ratios and low 143 Nd/ 144 Nd ratios in the ploeaws of rising or in the magma chamber, but the result of metasomatism of source mantle.