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| 1 | Geochemistry and environmental effect of cadmium in the super-large Jinding Pb-Zn deposit,Yunnan Province, China显示文摘The Jinding Pb-Zn deposit in Yunnan Province is the representative of a Cd-enriched area and mining activities lead to the release of Cd into the hypergenic ecosystem, resulting in Cd pollution. The concentrations of Cd vary greatly from one type to another type of rocks in the mining district. In the host rock, Cd concentrations range from 50×10-6 to 650×10-6 with an average of 310×10-6. In primary ores, Cd concentrations range from 14×10-6 to 2800×10-6 with an average of 767×10-6. However, in oxidized ores, Cd concentrations are highest, varying within the range of 110×10-6 to 8200×10-6 , averaging 1661×10-6. It is shown that the oxidized ores are the main carrier and environmental source of Cd. Leaching test showed that Pb/Zn ores are easy to oxidize and thereafter release Cd and other harmful elements. These leached elements in the leachate may be precipitated rapidly in the order of Zn>Pb>Cd. As for the concentration distribution of Cd in the Bijiang River, it is estimated to be 15.7 μg/L Cd in water, 49.3 mg/L in suspended substances, and 203.7 mg/L in sediments. The average value of Cd in soil from the polluted area is 83.0 mg/kg. Natural weathering of Cd-rich rocks and minerals imposes a potential environmental risk on the aquatic ecosystem of the Bijiang catchment. | LI Hang LI Dahua XIAO Tangfu HE Libin NING Zengping SUN Jialong ZHU Changsheng SHUANG Yan | 2008 | Chinese Journal Of Geochemistry2008，27，1： | 1 |
| 2 | Geochemical distribution, fractionation, and sources of heavy metals in dammed-river sediments: the Longjiang River, Southern China显示文摘In the present study, six sediment cores were collected from six river-dammed reservoirs to reveal the geochemical distribution of heavy metals(As, Cd, Pb, Sb,and Zn) in the Longjiang River, South China, which is highly impacted by nonferrous metal mining and smelting activities. The sediments were geochemically characterized, combining geochemical analysis, sequential extractions, and210 Pb chronology. The results indicated that the river sediments were severely polluted by heavy metals in the order of Cd [ Zn & Pb & Sb [ As. These heavy metals generally exhibited relatively low enrichment in the upstream sediments because of the limited anthropogenic impact, but their abundances drastically increased in the midstream sediments due to local smelting activities. In downstream sediments, the heavy metal concentrations(except for Cd) decreased, owing to the effect of dam interception and detrital inputs. Cadmium levels tended to increase in downstream sediments, which were attributed to the intensive discharge of Cd during the pollution event in 2012. The sedimentary records were traced back to1985, and a significant decrease of heavy metal enrichments could be found after the year 2000, suggesting the enhancement of environmental management in this period.The statistical results indicated that local metal smelting and mining activities were the main anthropogenic contributors for the enrichment of heavy metals in the dammed-river sediments. High enrichment factor and nonresidual fractions of heavy metals in local sediments may pose a direct threat to aquatic organisms. Cd presents significant danger because of its extreme enrichment and high labile fractions. | Xiaolong Lan Zengping Ning Yizhang Liu Qingxiang Xiao Haiyan Chen Enzong Xiao Tangfu Xiao | 2019 | Acta Geochimica2019，38，2： | 1 |
| 3 | Cadmium isotope compositions of Fe-Mn nodules and surrounding soils: Implications for tracing Cd sources显示文摘Cadmium (Cd) pollution in agricultural soils has become a severe threat to food security and human health in recent years. Stable Cd isotopes are a potentially powerful tool for identifying the sources of Cd in soils. However, many Earth surface processes, including adsorption, leaching, and biogeochemical cycles in plants, may generate Cd isotope fractionation, which can complicate the potential application of Cd isotopes in tracing the sources of Cd pollution in soils. In this work, the Cd isotope compositions of typical Fe-Mn nodules (FMNs) and surrounding soils in two different soil profiles are investigated. Our results show that the FMNs in lower layers (i.e., C and W horizons) are isotopically lighter than the surrounding soils by –0.114‰ to –0.156‰ (Δ114/110CdFMN-soil). We interpret this fractionation as the result of preferential adsorption of isotopically light Cd onto the surface of goethite. In the upper layers (i.e., P and A horizons), the Δ114/110CdFMN-soil values are more negative in the P horizon (–0.213‰ to –0.388‰) but more positive in the A horizon (0.061‰ to 0.204‰). We interpret these fractionations as the result of natural biogeochemical processes (i.e., leaching and biological cycling) during soil development. Soil leaching preferentially releases isotopically heavy Cd into the underlying soil (i.e., P horizon), shifting the topsoil towards lower δ114/110Cd values but the underlying soils towards higher δ114/110Cd values. Moreover, biological cycling contributes isotopically heavy Cd to the topsoil, probably shifting the topsoil towards higher δ114/110Cd values. Our study demonstrates that the formation of Fe oxyhydroxides, leaching, and biological cycling can considerably modify the soil Cd isotope signature, highlighting the need to consider natural biogeochemical processes when using Cd isotopes to trace heavy metal pollution in soils. | Ting Gao Yuhui Liu Yafei Xia Jian-Ming Zhu Zhengrong Wang Meng Qi Yizhang Liu Zengping Ning Qiqi Wu Wenpo Xu Chengshuai Liu | 2021 | Fundamental Research2021，1，3： | 1 |
| 4 | Exposure of children to heavy metals from artisanal gold mining in Nigeria:evidences from bio-monitoring of hairs and nails显示文摘In recent times,there had been reported cases of Pb poisoning in Anka gold mining area,Northwest Nigeria.Therefore,this study was carried out to determine the extent of bioaccumulation of heavy metals in the hairs and nails of children in the area.Forty samples(twenty nails and twenty hairs)samples were collected from ten boys and ten girls of ages 5–9 residing in the area.To ascertain the sources of heavy metals in children,15 soils samples,15 groundwater samples,5 samples of mine tailings,and 5 plants samples were collected.Hair and nails of the subjects were collected using internationally acceptable techniques.All samples were kept in uncontaminated ziplock bags prior to laboratory preparation and analysis.The samples were cleaned using nonionic detergent(triton X-100)and deionized water.The hairs and nails were digested with 10 mL of 6:1 mixture of nitric acid and perchloric acid.The soils,mine tailings,and plants were air-dried at room temperature,sieved,and chemically digested using the aqua regia method.The concentrations of metals in all the samples were determined using highperformance liquid chromatography–inductively coupled plasma–mass spectrometry.Statistical analysis was employed to unravel potential sources of metals in the media.Results showed that heavy metals in children of the area are above results from similar studies and pathological ranges for heavy metals in hairs and nails.Also,heavy metals in environmental media are above the recommended standards.Multivariate analysis showed that the metals are mainly from mining and other anthropogenic sources.Results of correlation between heavy metals in hairs and nails with those in geological samples revealed that heavy metal that bioaccumulates in the children of this area are mostly from contaminated environmental media.It is recommended that complete remediation and effective health education be carried out in the area. | Adeniyi JohnPaul Adewumi Temitope Ayodeji Laniyan Tangfu Xiao Yizhang Liu Zengping Ning | 2020 | Acta Geochimica2020，39，4： | 0 |
| 5 | Two-step calculation method to enable the ecological and human health risk assessment of remediated soil treated through thermal curing显示文摘The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site pollution.However,few studies have evaluated the ecological and human health risks of reusing these remediated soils.Considering Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal curing.The pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching periods.Furthermore,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction content.Moreover,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk value.Therefore,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated soil.In contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil. | Shaowen Xie Fei Wu Zengping Ning Manjia Chen Chengshuai Liu Qiang Huang Fangyuan Meng Yuhui Liu Jimei Zhou Yafei Xia | 2021 | Soil Ecology Letters2021，3，3： | 0 |
| 6 | Bioavailability of Tl in soils, uptake by crops and its environmental impact显示文摘 | Libin HE Tangfu XIAO Hang LI Jingquan PENG Zengping NING Jialong SUN Fei YANG | 2006 | Chinese Journal Of Geochemistry2006，25，B08： | 0 |
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