生态修复后某矿区下游农田土壤金属污染特征与风险评价

为研究广东省某矿区开展生态修复多年后下游农田土壤的金属污染状况，选取该矿区下游某村周边农田土壤及灌溉水渠作为研究对象，对该区域采集了40个土壤表层样本和8个水体样本，利用Arcgis软件对农田土壤样品中As、Cu、Cd、Pb、Zn、Mn和Fe₂O₃的质量分数进行克里金空间插值，解析该区域农田土壤金属的空间分布特征；采用综合污染指数法和潜在生态风险指数法对该区域耕作层土壤中As、Cu、Cd、Pb、Zn和Mn进行风险评价。结果表明，40个土壤样品中As、Cd、Cu、Zn和Pb的超标率分别为77.5%、70%、87.5%、27.5%和67.5%,说明调查区域农田土壤污染属于多金属复合污染，且对农作物的生产和安全产生巨大的威胁。部分土壤样品中As、Pb和Cd含量超过了中国农用地土壤污染风险管制值，需采取严格管控措施。通过分析土壤金属的空间分布，发现土壤金属含量超标点位主要位于灌溉口与受污染河流周边，且含量与离灌溉口距离成反比。结合目前灌溉水样中的金属均未超标的情况，得出该区域农田土壤污染是由该矿区生态环境修复前所产生的含金属灌溉水导致土壤中金属的积累...     

云南个旧土壤农作物重金属污染特征及潜在风险

在实地调查和实验室分析的基础上,对云南省个旧市大屯镇土壤农作物重金属污染状况进行了评价。结果显示:个旧市大屯镇调查区域土壤中Pb、Zn、Cd、As平均质量分数分别为943. 5、454. 8、3. 4、302. 1 mg/kg,分别为国家农用地土壤污染风险管控标准筛选值的7. 8、1. 8、11. 2、10. 1倍,土壤污染严重。土壤Cd的生态危害最强,As、Pb的生态危害次之,Zn表现为轻微的生态危害。从潜在生态危险指数来看,所采集的土壤样品皆表现为极强的生态危害。所采集农作物与食品安全国家标准对比,结果显示,大米中Pb、Cd和As的超标率分别为35%、55%和100%;玉米中Pb、Cd和As的超标率分别为13%、0%和0%;小苦菜Pb、Cd和As的超标率分别为100%、60%、100%;小米菜中Pb、Cd和As的超标率均为100%,蔬菜类的重金属超标情况相对于谷物类较为严重。研究区域土壤样品总量Pb、Zn与有效态皆呈极显著正相关关系,总量Cd与有效态呈弱正相关关系,总量As与有效态表现为相关性不显著。     

鞍山市大气尘和金属元素沉降通量及污染特征

通过采集鞍山市11个点位的降尘样品以及土壤样品,用ICP-MS分析了Cu、Mn、Zn、Pb等元素含量,并计算其沉降通量。结果表明,鞍山地区大气降尘的沉降通量为2.92～59.8g/(m2.month),其中鞍钢厂区沉降通量均值为31.6g/(m2.month),分别是周边地区和对照地区的4.72倍和10.5倍。重金属As、Cr、Pb和Cd的沉降通量分别为3.78、45.5、42.8、0.457g/(hm2.month)。降尘中各元素的富集系数为0.29～190,其中Cu、Fe、Zn、Mo、Cd、Pb和Se的富集系数大于10,说明这些元素主要来自于人为源。鞍钢厂区土壤中Cu、Pb、Mn、Zn、Mo、Cd、Ca、Fe和Se的含量较辽宁省土壤背景值高,说明其土壤环境已经受到了人类活动的影响。     

长沙市某集中式饮用水水源地周边土壤重金属污染特征和风险评价

以长沙某河库兼用型饮用水水源地一、二级保护区土壤为研究对象，于2018年8月采用网格布点法在一级和二级保护区分别布设3个和7个采样点，在水源地历史采样区布设5个采样点，探究土壤中Cd、Pb、Cr、Cu、Zn、Ni、Hg、As的含量分布及污染水平。结果表明：土壤中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的含量均值分别为46.56、4.90、81.87、46.64、0.19、30.11、75.11、237.93 mg/kg。重金属元素含量均值超过农用地污染风险筛选值的样品占比排序为Cd （86.7%）>Zn （60%）>As （53.3%）>Cu （6.7%）=Pb （6.7%）。土壤中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的单因子污染指数分别为1.55、16.34、0.41、0.47、0.08、0.30、0.63、0.95，主要为Cd、As污染。研究区土壤重金属综合污染指数为11.71，属重污染等级。水源地一级保护区、二级保护区、历史采样区2018年、历史采样区2014年土壤重金属综合污染指数分别为20.41、14.94、1.98、1.17。后期应加强对该饮用水水源地土壤中Cd、Pb、Cu、Zn、As的污染控制和治理。     

新疆焉耆县耕地土壤重金属的空间分布及来源解析

在新疆焉耆县采集53个耕地土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn的质量比,基于GIS技术研究其空间分布格局,运用多元统计分析法区分其主要来源。结果表明:焉耆县耕地土壤中Cd、Cr、Ni、Pb和Zn的质量比平均值分别超过新疆灌耕土背景值的0.50、0.40、0.33、1.63和3.92倍;在研究区内As、Cd、Pb质量比呈现由北向南逐渐升高趋势,Cr、Cu、Zn质量比呈现由北向南降低趋势,Mn和Ni质量比出现西部高值区;耕地土壤中As、Cd、Ni和Pb的来源主要受人类活动的影响,Cu和Mn的来源主要受土壤地球化学作用的控制,Cr和Zn的来源可能受人为污染与自然因素共同控制。     

苏州市南郊农田土壤和蔬菜中砷、铬、铅、镉的分布特征研究

通过对苏州市南郊农田土壤和蔬菜中砷(As)、铬(Cr)、铅(Pb)、镉(Cd)含量的监测分析,结果表明:土壤样品中,除As的总质量比平均值低于江苏省土壤背景值外,其余均高于背景值;而蔬菜样品中4种元素的总质量比平均值均低于《食品安全国家标准食品中污染物限量》(GB 2762—2012)中的限量值。聚类分析表明,土壤中Cd、Pb累积较多,Cr次之。同时,BCR连续提取法和相关性分析表明:土壤中As和Cr主要以残渣态为主;Pb以可还原态为主,弱酸提取态次之;Cd以弱酸提取态为主,可还原态次之。可见,土壤中Cd相对于其他3种元素具有较高的生物有效性和潜在危害性。     

典型铝塑厂周边土壤重金属分布特征与健康风险评价

为探究铝塑园区周边土壤重金属污染情况,选取山东省某城市塑料开发区为研究区,按照分层采样方式获取到80个土壤样品,分别测定土壤中As、Cd、Hg、Cr、Cu、Ni、Pb、Zn含量,运用统计分析法探讨土壤重金属等的分布特征和来源,并利用健康风险评价模型确定了土壤重金属对周边居民的健康风险。结果表明:As、Cd、Hg、Cr、Cu、Ni、Pb和Zn均超出山东省土壤背景值,其中Cd、Hg、Cu和Pb分别超出背景值48. 15%、106. 90%、62. 04%和39. 96%,表明土壤中存在一定程度的重金属积累,在周边140～210 m处最为严重,且受人类活动影响强烈,与风向关系不大;土壤重金属垂直分布特征大致呈现随着深度的增加不断增加,在20 cm深度附近达到最高值,其后不断降低并趋于平稳,Cd、Hg、Cu、Pb和Zn变异幅度大,受到人为干扰较大,As、Cr和Ni主要受成土母质控制,属于自然来源,变动幅度较小;研究区内8种元素不存在非致癌风险,Cr、As、Ni和Cd产生的致癌风险处在可接受范围内,但存在的潜在致癌风险应引起足够的重视。     

徐州城市表层土壤中重金属的富积、分布特征与环境风险

研究了徐州城市表层土壤的21个样品中30种元素的富集与分布特征。结果表明,与我国土壤元素的背景值(算术平均值)相比,表层土壤中Zn、Cd、As、Hg、Sb、Sn、Ag等元素富集大;Fe、Se、Sc、Ba、Bi、Pb、Cu、Ni、Cr、Mn、Mo、Be、Ti、Al、Ga、Li、Co等元素的富集较小。污染元素的空间分布特征显示了Zn、Cu、Pb、Cd等元素主要与交通运输等扩散污染源相关,而元素As、Sb的空间分布主要与工业污染源(点源)有关。环境风险指数的计算结果表明,表层土壤中重金属污染具有较大的环境风险,其中属于中等环境风险级别以上的样品占近40%,而且高风险区域主要集中在钢铁厂和化机厂等工业区范围内。     

典型铅蓄电池场地土壤污染识别与调查研究

以成都平原某废弃铅蓄电池污染场地为例,调查识别典型工业场地主要污染物空间分布特征和剖面迁移特征。结果表明:场地主要潜在Pb污染源有建筑垃圾、土壤及残留废水,潜在污染途径为大气降尘、含Pb废水排放;建筑垃圾中Pb、Cd、As等污染严重;场地内酸液暂存池和清洗池地表水中Pb、Cd超标严重,均为劣Ⅴ类;场地内及周边环境地下水中Cd、Cr污染较重;区内表层土壤中Pb、Cd污染严重,且呈面源性,距循环水池及酸液暂存池1.2 m处土壤中Pb含量远高于周边区域。     

粤北某离子吸附型稀土矿山土壤和地表水重金属分布及风险评价

对粤北某离子吸附型稀土矿24个土壤样品中的As、Cd、Cr、Cu、Mn、Ni、Pb、Zn和Hg,以及15个地表水样品中的As、Cd、Cu、Hg、Mn、Pb和Zn进行了检测,并以多元统计分析与土壤潜在生态风险指数法、地表水健康风险评价模型相结合的方式,研究了重金属的分布特征及风险水平。结果表明:在土壤中,Mn、Zn、Cd和Pb的平均含量均超过了背景值;Mn、Cr、Ni、Cu、Cd和Zn在采区有较明显集聚,As、Pb和Hg的高含量分布相对均匀;Cr、Ni、Cu和Pb含量主要受区域背景影响,Zn、As、Cd和Hg含量与矿区人类活动关系密切,Mn含量受自然和人为因素共同控制;重金属造成的土壤潜在生态风险整体处于轻微水平,Ⅱ采区和Ⅶ采区生态风险较高;Cd和Hg是造成土壤生态危害的主要重金属元素。在地表水中,Mn的平均浓度超过了《地表水环境质量标准》(GB 3838-2002)规定的限值,其余重金属的含量均满足该标准中的Ⅲ类水质要求;重金属浓度在靠近采区及位于河流中下游的位置偏高;Mn、Cd、Pb、Zn和Cu浓度受稀土开采影响较大,As、Hg浓度主要受自然因素影响;重金属产生的健康总风险(9.39×10^-7~1.01×10^-6 a^-1)低于国际辐射防护委员会推荐的参考标准(5×10^-5 a^-1),但儿童通过饮水途径受到的健康风险(1.01×10^-6 a^-1)略超过部分机构的推荐限值;Cd和As是地表水中产生健康风险的主要重金属元素。综上,研究区重金属污染风险管理的主要对象是Cd和Mn。     

Characteristics and distribution of analyzed metals in soil profiles in the vicinity of a postflotation waste site in the Bukowno region, Poland

The lead–zinc industry in the Bukowno region of southern Poland has polluted the surface layer of the surrounding soils mainly with lead (Pb), cadmium (Cd), zinc (Zn), arsenic (As), and thallium (Tl). Analysis of six soil profiles, taken on the east side of the postflotation waste site of the Mining and Metallurgical Plants ZGH "Boles?aw" in Bukowno, showed that they were podzol soils, taking form of loose sands with neutral pH and reducing conditions. Concentration of organic matter in the horizons ranged from 2 to 80 %. The main components of the mineral soil were quartz, carbonates, K-feldspars, plagioclases, and micas (sericite). The highest total concentrations of metals were found in the O, A, and B horizons. Over 90 % of the Cd content, 80 % of the Pb content, 60 % of the Zn content, ～60 % of the Tl content, and 20 % of the As content occurred as mobile forms. The corresponding total concentrations were 10 mg/kg Cd, 922 mg/kg Pb, 694 mg/kg Zn, <1 mg/kg Tl, and <5 mg/kg As. This can potentially be taken up from the soil and transported in the trophic chain. Comparing the total metal content with the legal limits in Poland, it is observed, that the investigated soils exceeded the permissible levels of Cd, Pb, and Zn for agricultural soils. Arsenic and Tl are not reflected in the chemical quality of soil classifications.     

鞍山市郊蔬菜基地土壤重金属污染状况调查

通过对鞍山市郊蔬菜基地土壤中重金属含量的分析表明,所采集的菜地土壤中Cd的超标率为44．4％,Cu、Pb、Cr、As、Hg无超标现象。大田菜菜地土壤中As、Hg、Pb含量比大棚菜菜地略高,Hg、Pb、Cu、Cr、Cd含量超背景值。     

Spatial distribution,temporal variation,and sources of heavy metal pollution in groundwater of a century-old nonferrous metal mining and smelting area in China

This study first presents the spatial distribution, temporal variation, and sources of heavy metal pollution in groundwater of a nonferrous metal mine area in China. Unconfined groundwater was polluted by Pb, Zn, As, and Cu, in order, while confined karst water in the mines showed pollution in the following sequence: Zn, Cd, Cu, Pb, and As. Pollution by Pb was widespread, while Zn, As, Cu, and Cd were found to be high in the north–central industrial region and to decrease gradually with distance from smelters and tailings. Vertically, more Pb, Zn, Cu, and Cd have accumulated in shallow Quaternary groundwater, while more As have migrated into the deeper fracture groundwater in the local discharge area. Zn, Cd, and Cu concentrations in groundwater along the riverside diminished owing to reduced wastewater drainage since 1977, while samples in the confluence area were found to have increasing contents of Pb, Zn, As, Cu, and Cd since industrialization began in the 1990s. Sources of heavy metals in groundwater were of anthropogenic origin except for Cr. Pb originated primarily from airborne volatile particulates, wastewater, and waste residues and deposited continuously, while Zn, Cd, and Cu were derived from the wastewater of smelters and leakage of tailings, which corresponded to the related soil and surface residue researches. Elevated As values around factories might be the result of chemical reactions. Flow patterns in different hydrogeological units and adsorption capability of from Quaternary sediments restricted their cross-border diffusion.     

铅冶炼企业周边大气降尘中铅、镉、砷量及其对土壤的影响

通过在2012年5月-2013年4月1个周期年内，对修复基地和对照点每月大气降尘中铅、镉、砷沉降量的监测，结果表明：修复基地大气降尘中铅、镉、砷含量明显较对照点高，年总沉降量分别是对照点的17．6倍、16．3倍和14．1倍，表明铅冶炼企业对基地大气降尘中铅、镉、砷含量影响显著；大气降尘中铅、镉、砷沉降量受位置和时间影响较大，在相距不到100 m的测点间，沉降量相差1倍以上，冬季主导风明显、地面植被少、二次扬尘大，使处于铅冶炼企业下风向的基地降尘中铅、镉、砷沉降量较大。沉降量时空不均匀与土壤污染不均匀现状一致，也验证了铅冶炼企业是基地大气和土壤重金属污染的主要来源。以降尘缸模拟土壤进行测算，结果表明大气降尘中镉对土壤污染速度最快，风险最大。     

Mobility of selected trace elements in Mediterranean red soil amended with phosphogypsum: experimental study

Soil amendment by phosphogypsum (PG) application becomes of increasing importance in agriculture. This may lead, however, to soil, plant, and groundwater contamination with trace elements (TEs) inherently present in PG. Monitoring of selected TEs (Pb, Zn, Cu, and Cd) distribution and mobility in a Mediterranean red soil profile has been performed in soil parcels applied with PG over a 16-month period. Concentrations were measured in soil and plant samples collected from various depth intervals at different points in time. TEs sequential extraction was performed on soil and PG samples. Results showed soil profile enrichment peaked 5 months after PG application for Cd, and 12 months for Pb, Zn, and Cu. Rainwater, pH, total organic carbon, and cationic exchange capacity were the main controlling factors in TEs accumulation in soils. Cd was transferred to a soil depth of about 20 cm. Zn exhibited mobility towards deeper layers. Pb and Cu were accumulated in around 20-55-cm-deep layers. PG increased the solubility of the studied TEs; PG-applied soils contained TEs bound to exchangeable and acid-soluble fractions in higher percentages than reference soil. Pb, Zn, and Cu were sorbed into mineral soil phases, while Cd was mainly found in the exchangeable (bio-available) form. The order of TEs decreasing mobility was Zn > Cd > Pb > Cu. Roots and leaves of existed plants, Cichorium intybus L., accumulated high concentrations of Cd (1-2.4 mg/kg), exceeding recommended tolerable levels, and thus signifying potential health threats through contaminated crops. It was therefore recommended that PG should be applied in carefully established, monitored, and controlled quantities to agricultural soils.     

Distribution and fractionation of cadmium, copper, lead, nickel, and zinc in a calcareous sandy soil receiving municipal solid waste

This study was conducted to evaluate the degree of mobility and fractionation of cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) after the addition of municipal solid sewage sludge (MSS) in a sandy calcareous soil. Treatments were (1) soil application of MSS, (2) soil application of enriched municipal solid waste compost (EMSS), and (3) control soil. The MSS application represented a dose of 200 Mg dry weight per hectare. Soil columns were incubated at room temperature for 15 days and irrigated daily with deionized water to make a total of 505 mm. At the end of leaching experiments, soil samples from each column were divided into 14 layers, each being 1 cm down to 10 and 2.5 cm below that and analyzed for diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, Ni, and Zn. The fractionation of the heavy metals in the top five layers of the surface soil samples was investigated by the sequential extraction method. All soil layers of the columns receiving MSS and EMSS had significantly higher concentrations of DTPA-extractable heavy metals than control soil. The maximum concentration of heavy metals in treated soil was in the surface layer and declined significantly with depth. Sequential extraction results showed that in the treated soil, a major proportion of Cd, Pb, and Ni was associated with organic matter (OM) and exchangeable (EXCH) fractions, and a major proportion of Cu and Zn was associated with residual (RES) and OM fractions. Based on relative percent, Pb, Cd, and Ni in the EXCH fraction was higher than Cu and Zn in soil leached with MSS and EMSS, suggesting that application of this MSS to a sandy calcareous soil, at the loading rate used here, may pose a risk in terms of groundwater contamination with Pb, Cd, and Ni.     

湖南省某冶炼厂周边农田土壤重金属污染及生态风险评价

利用野外采样与实验室分析相结合的方法,以湖南省某冶炼厂周边农田土壤(0~20 cm)为研究对象,监测了Cd、As、Pb、Cr、Cu、Zn、Hg等7种重金属的含量,并对重金属污染程度与潜在生态风险进行了评价。结果表明,7种重金属都存在不同程度的超标或污染,其中Cd、As、Pb等的污染较为严重。统计学分析结果表明,Pb、As、Hg、Zn、Cd等来源相同,可能主要都来自于人为污染,即冶炼作业造成的污染。7种重金属化学形态不尽相同:在重金属有效态中,Cd的水溶态和可提取态较高;Pb、Cu、Zn可还原态、可氧化态这两部分含量较高。而Hg、As、Cr的残渣态含量较高。风险评价代码评价结果表明,Cd的生态风险较高,4.5%的样点Cd为极高生态风险,52.8%的样点Cd为高生态风险,42.7%的样点Cd为中度生态风险;100%的样点Zn为中度生态风险;Cu有60.1%的样点属于低生态风险,39.9%的样点属于中度生态风险;As、Pb主要以低生态风险为主(所占比例分别为77.2%、80%);Hg主要以无生态风险为主(所占94.3%)。Hakanson潜在生态风险指数法计算的综合潜在生态风险指数(RI)的范围为46.4~1 627.5,表明研究区域农田土壤存在很高的生态风险。上述各项结果综合表明,研究区农田土壤受到了严重的重金属污染,由此引起的重金属生态风险应引起高度关注。     

高压密闭消解土壤砷、汞、铅、镉酸体系比较

采用高压密闭消解系统消解土壤,氢化物发生-原子荧光光谱法(HG-AFS)测定As和Hg,石墨炉原子吸收光度法(GF-AAS)测定Pb和Cd,对比了不同消解酸体系对国家土壤标准参考样中As、Hg、Pb、Cd的消解效果。结果表明,盐酸-硝酸体系对As、Hg、Pb和Cd的消解平均回收率分别为26.1%、100.6%、69.7%、87.3%;硝酸-高氯酸-氢氟酸体系中As、Hg、Pb和Cd消解平均回收率分别为109.9%、84.7%、87.5%、90.1%;硝酸-双氧水体系对Hg、Pb、Cd消解平均回收率分别为104.8%、95.1%、93.3%,对As的回收率虽只有69.2%,但数据精密度最好。此外,从简化试验步骤,减少误差,提高检测效率及减少试验危险性等方面综合评价,认为硝酸-双氧水消解体系是采用高压密闭系统消解土壤重金属的最理想酸体系。