葫芦岛锌厂周边农田土壤重金属浓度的空间变异及污染评价

以葫芦岛锌厂为中心在15 km范围内采集农田表层及剖面土,对Cr、Cu、Ni、Pb、Zn、Cd、Hg和As共8种重金属的含量和空间分布进行分析,采用单因子污染指数法、内梅罗综合污染指数法和富集因子法对其污染现状进行评价,分析重金属污染的特征,并通过主成分分析探究其污染源。结果表明,锌厂周围农田土壤重金属呈现不同程度的富集,其中Hg和Cd的污染程度最大,研究区总体处于重度污染水平。土壤重金属污染多以锌厂为中心,距锌厂越远,污染越小。主成分分析表明,第1主成分中Zn、Cd、Cu、As、Pb和Hg负荷较高,结合相关性分析结果,推断上述重金属主要受工业生产、交通运输等人为活动影响;第2主成分中Ni、Cr负荷最高,且Ni、Cr与土壤背景值接近,主要受成土母质及其风化物的影响。     

藏中矿区重金属污染土壤的微生物活性变化

微生物几乎参与土壤中的一切生物及生物化学反应,土壤微生物活性可较敏感地反映土壤中生化反应的方向和强度,是探讨重金属污染生态效应的有效途径之一。通过野外调查与采样和室内分析,研究了藏中矿区重金属污染对土壤酶活性、基础呼吸、代谢商(qCO2)和可矿化N的影响。结果表明,矿区土壤受重金属Cu、Zn、Pb、Cd不同程度污染,使得土壤酶活性、可矿化N受到抑制,基础呼吸和qCO2则受到刺激。逐步多元回归分析表明,在Cu、Zn、Pb、Cd复合污染条件下,矿区土壤重金属复合污染对土壤微生物活性的影响是复杂的;主成分分析表明,土壤总体微生物活性指标能较好地反映拉屋矿区土壤重金属复合污染状况,可作为藏中矿区土壤环境质量评价及量化分类的有效指标。     

贵州省丹寨县某铅锌矿区土壤重金属污染生态风险评价

对贵州省丹寨县某铅锌矿及周边土壤重金属污染进行调查,分析了铅锌矿区土壤中6种重金属的总量和形态,用潜在生态指数法、次生相与原生相比值法对重金属的生态风险进行评价。结果表明,0～10 cm土壤中Pb、Zn、Mn、Cu、Hg和Cd含量是贵州土壤背景值的5.69、3.91、0.80、0.58、9.64和1.50倍。与《土壤环境质量农田用地土壤污染风险管控标准(试行)》(GB 15168—2018)相比,尾矿堆积区土壤中Pb、Zn和Cd含量均高于风险筛选值; 10～20 cm土壤中Pb、Zn、Hg和Cd含量高于贵州省土壤重金属背景值,尾矿堆积区、尾矿堆积区的农田和尾矿附近河流区下游土壤中Zn和Cd含量超过风险筛选值。形态分布主要以残渣态为主,可交换态以Exc-Pb占比最高(20.9%);碳酸盐结合态以CARB-Zn占比最高(26.2%);铁锰氧化物结合态以RED-Mn占比最高(31.8%);有机结合态以OM-Mn占比最高(48.7%)。生物可利用态表现为ZnPbHgCdCuMn,潜在生物可利用态表现为MnPbCdHgZnCu。潜在生态指数评价表明,尾矿堆积区的农田、尾矿堆积区下游村寨和尾矿附近河流区下游的单项潜在生态风险处于高生态风险等级,Hg对潜在生态危害指数的贡献率达60.9%;次生相与原生相比值法评价显示,土壤中Mn和Cd的生态风险最大。     

玛曲高寒退化草甸土壤重金属污染风险评价

为了分析玛曲高寒草甸土壤重金属含量分布及重金属污染风险,采集玛曲高寒退化草甸土壤样品,分析研究区表层土壤(0—20 cm)中Cr、Ni、Cu、Zn、As、Cd、Hg、Pb等八种重金属含量,描述玛曲高寒草甸土壤重金属的空间分布特征,采用单因子污染指数、内梅罗污染指数、地累积指数评价重金属污染程度并分析重金属污染潜在生态风险,以相关性分析、主成分分析和聚类分析表征同源性重金属。结果表明:(1)研究区内As、Cd的质量分数高于背景值, Ni的质量分数偏低,变异系数大小为Cr> Hg> Cd> Cu> As> Ni> Zn> Pb;(2)Cd单因子污染指数为轻微污染,地累积指数反映As属于未受污染与轻微污染之间,各重金属元素均无潜在生态风险;以国标和土壤背景值为标准,内梅罗综合污染指数表明玛曲未受到重金属污染;(3)主成分和相关性分析表明玛曲土壤中Ni、Cu、Zn、As、Cd、Pb等元素具有相同或相似的来源, Ni和Pb的来源优先顺序最大, Cr和Hg含量呈现弱相关。     

长期重金属胁迫对农田土壤微生物生物量、活性和种群的影响

调查了沈阳张士灌区长期污水灌溉造成的原位农田土壤重金属污染状况,从土壤微生物生物量、微生物活性和微生物种群数量的角度评价了长期重金属污染对农田土壤生态系统的影响.结果表明,张士灌区土壤存在严重的Cd污染,土壤Cd含量达1.75～3.89 mg·kg ^-1,部分区域还伴有Cu、Zn复合污染.在目前污染程度下,土壤微生物生物量碳(C_mic)、微生物商(qM)、土壤脱氢酶活性以及自生固氮菌数量随土壤重金属含量增加呈下降趋势,代谢商(qCO₂)随土壤重金属含量增加显著升高,而底物诱导呼吸强度(SIR)、纤维素酶活性以及细菌、放线菌和真菌数量无明显变化.相关性分析表明,土壤Cd含量变化是影响微生物参数变化的主要因素,在微生物参数中微生物商和代谢商对重金属污染最敏感.     

铜陵铜尾矿凤丹种植基地重金属污染初探

通过对安徽铜陵凤凰山铜尾矿凤丹种植基地土壤和凤丹中重金属污染状况进行采样分析.结果表明,在尾矿空白地和凤丹种植地土壤中Cu、Cd、Pb、Zn元素含量、存在形态差异明显,说明凤丹对尾矿土壤的修复效果明显;尾矿土壤中的Cu、Cd元素总量分别是国家土壤环境质量二级标准的436～1443倍和3.67～3.86倍,凤丹种植地重金属元素的CPI指数达到5.607,表明尾矿土壤中重金属元素污染仍相当严重.研究发现,4种元素在凤丹各部位含量明显不同:叶和根心为Cu>Zn>Pb>Cd,茎和根皮为Zn>Cu>Pb>Cd,根皮中Zn含量最高;土壤中重金属元素各形态的变化与凤丹体内相应元素总量无显著相关;丹皮内Cu、Cd、Pb元素含量与丹龄之间相关系数分别为0.842、0.993、0.992,Cu、Cd元素在凤丹体内含量约是出口药用植物绿色行业限量指标的1.43～2.53倍和1.17～3.17倍,可见缩短栽种时间可有效减少重金属元素对丹皮药效的影响.     

五节芒对重金属污染土壤微生物生物量和呼吸的影响

选择3个五节芒在重金属污染地的定居点作为研究样地,其中两个为Pb/Zn矿尾矿砂堆积地（W：黄岩铅锌尾矿;Y：三门铅锌尾矿）,一个为冶炼厂附近污染农田（N）,分别测定其根围与根际土壤微生物基础呼吸、微生物量碳、微生物量氮、土壤理化特性和土壤重金属含量.结果表明：根际土壤微生物基础呼吸和微生物量氮均显著地高于根围土壤（P<0.05）,除了N样地外,微生物量碳在根围与根际之间差异不显著（P>0.05）.根际土壤有机碳、总氮（Y样地除外）和离子交换量（N样地除外）低于根围土壤.根际重金属（Pb、Zn、Cu、Cd）总量与DTPA（二乙三胺五乙酸）可提取量普遍低于根围土壤.冗余分析（RDA）表明,根围和根际土壤微生物与土壤理化特性呈不同程度的正相关,而与土壤重金属含量呈现不同程度的负相关.主分量及回归分析同样证明土壤微生物总体变化与土壤理化特性呈正相关（根围R²=0.653;根际R²=0.690）,而与重金属含量呈负相关（根围R²=0.610;根际R²=0.662）.     

长期灌溉含多环芳烃污水对稻田土壤酶活性与微生物种群数量的影响

以沈抚污水灌区为例,研究了长期灌溉含多环芳烃(PAHs)污水对稻田土壤酶活性、微生物种群数量的影响。结果表明,灌区稻田土壤PAHs含量在319.5～6362.8μg.kg-1。长期污水灌溉导致稻田土壤PAHs含量严重超过环境标准。随清水连续灌溉年限的增加,土壤PAHs总量不同程度降低直至低于土壤PAHs环境质量标准。相关性分析表明,在目前污染程度下,灌区稻田3大土壤微生物类群和主要功能群的种群数量主要受土壤理化性质的影响,受PAHs含量影响不明显。土壤全氮含量与细菌数量呈极显著正相关(P<0.01)。土壤酶活性受到土壤养分和PAHs污染的双重影响,土壤有机碳和全磷含量分别与脱氢酶、多酚氧化酶和脲酶活性呈极显著正相关(P<0.01),PAHs含量分别与脱氢酶和脲酶活性呈极显著正相关(P<0.01),与多酚氧化酶活性呈显著正相关(P<0.05)。     

铜川煤矿区重金属污染对土壤微生物群落代谢和酶活性的影响

研究了陕西省铜川煤矿矿区的重金属污染状况以及不同程度的重金属污染对土壤微生物代谢、微生物群落功能以及土壤酶活性的影响.结果表明： 铜川矿区土壤中重金属Cu、Zn、Cd、Pb全量及有效量均显著高于非矿区土壤,其中Cd污染最为严重.采用Biolog方法结合主成分分析和聚类分析发现,随着污染程度的增加,不同土壤微生物群落间的代谢特征发生显著变化,而且这种变化主要体现在糖类和氨基酸类碳源的利用差异.在轻度、中度污染情况下,土壤微生物群落对碳源的利用表现出激活效应;而在重度污染的情况下,土壤微生物群落对碳源的利用表现出抑制效应.随着污染程度的增加,脲酶、蛋白酶、碱性磷酸酶和过氧化氢酶的活性均呈现降低的趋势,矿区土壤脲酶、蛋白酶、碱性磷酸酶和过氧化氢酶活性分别是非矿区土壤中相应酶活性的50.5%～65.1%、19.1%～57.1%、87.2%～97.5%、77.3%～86.0%;蔗糖酶和纤维素酶在中等污染程度以下的土壤中表现为激活效应,而在重度污染的土壤中表现为抑制效应.     

贵州织金县贯城河上游煤矿区富硒高镉土壤重金属的分布特征及生态风险评价

通过对贵州省织金县贯城河上游煤矿区煤(矸石)、周边土壤Cd、Cr、Ni、Cu、Zn、Pb、As和Se含量进行测定,分析了煤(矸石)、土壤重金属及Se的含量特征,探讨了土壤重金属元素的来源,运用单因子污染指数、内梅罗综合污染指数、地积累指数和潜在生态风险指数4种方法评价了土壤重金属污染程度及潜在生态风险。结果表明:(1)煤(矸石)中Cr、Se、Pb含量均高于世界煤的平均含量,Ni、Cu、Zn、Cd含量均高于世界和中国煤的平均含量。(2)除Pb外,土壤样品中Cd、Ni、Cu、Cr、Zn、As、Se含量较高,其平均含量均高于贵州省土壤背景值,尤其以Se、Cd和Cu突出。(3)研究区土壤具有富硒高镉、局部酸化的特点,土壤Cd、Se、Cr、Ni和Zn的来源具有一定共性,这与长期的采煤活动有关。(4)研究区土壤重金属的单因子污染指数排序为:CdCuNiZnCrAsPb,土壤重金属综合污染处于重度污染水平;土壤Cr、Ni、Cu、Zn、As、Pb的环境风险等级属于轻微级别,Cd的环境风险程度总体上处于很强级别;4种方法的评价结果基本一致,Cd的单因子污染指数最大、地积累指数最高、污染情况和潜在生态危害程度最严重,对潜在生态风险指数贡献最大。     

节节草生长对铜尾矿砂重金属形态转化和土壤酶活性的影响

通过盆栽模拟栽培试验,研究了节节草生长对铜尾矿砂重金属形态转化和土壤酶活性的影响。结果表明,节节草生长显著提高了尾矿砂中有机物结合态重金属比例(P0.01),降低了交换态和残渣态重金属比例(P0.05)。土壤过氧化氢酶、脲酶、多酚氧化酶和蔗糖酶活性均随着节节草的生长而不同程度的升高,其中过氧化氢酶和脲酶活性均与植物生长时间呈显著正相关(r过氧化氢酶=0.911,P0.05;r脲酶=0.957,P0.01),多酚氧化酶和蔗糖酶活性在植物生长旺盛期达到峰值,分别是对照组的2.40和2.02倍,随后迅速下降;而磷酸酶活性却显著下降(r磷酸酶=-0.923,P0.05)。土壤酶活性与节节草地下部分干重的相关性大于地上部分;且与土壤有机物结合态重金属的含量呈显著正相关,与交换态和残渣态重金属含量呈显著负相关。节节草生长不仅促进了铜尾矿砂重金属朝螯合态方面转化,有效降低重金属的生物有效性,同时还显著地改善了铜尾矿砂的基质环境和土壤肥力。因此,节节草在铜尾矿废弃地恢复实践中具有较大的应用潜力。     

工矿区不同类型生物结皮对大气降尘重金属的富集规律及其影响因子

大气降尘是矿区土壤重金属的主要来源,而生物结皮对大气降尘重金属有显著的富集作用。为探究不同类型生物结皮对大气降尘重金属的富集规律及其影响因子,选取宁东典型火电厂周边生物结皮广布区作为试验样地,3类生物结皮作为研究对象,并以临近裸土作为对照,对比分析了生物结皮富集大气降尘过程中土壤理化性质、酶活性及重金属含量的变化,采用相关分析、冗余分析和方差分解方法探讨了不同类型生物结皮的结皮层(A层)和层下土壤(B层)重金属含量与其土壤物理、化学性质及酶活性之间的关系。结果表明：燃煤烟尘是矿区大气降尘重金属污染的主要来源,涉及重金属元素包括Cd、Cr、Hg、Pb、Zn、As。生物结皮对源自大气降尘的重金属元素均具有显著的富集作用,且在不同演替阶段生物结皮间的富集规律完全一致：藓结皮>混生结皮>藻结皮;重金属综合污染指数评价结果显示：生物结皮对重金属具有表层富集效应,表现为A层污染程度高于B层。不同类型生物结皮A、B层综合污染指数存在显著差异,排序为：藓结皮>混生结皮>藻结皮;和对照相比,三类生物结皮均能通过富集大气降尘增加其A、B层养分和细颗粒物含量并改善土壤质地。方差分解结...     

Red mud (RM)-Induced enhancement of iron plaque formation reduces arsenic and metal accumulation in two wetland plant species

Human activities have resulted in arsenic (As) and heavy metals accumulation in paddy soils in China. Phytoremediation has been suggested as an effective and low-cost method to clean up contaminated soils. A combined soil-sand pot experiment was conducted to investigate the influence of red mud (RM) supply on iron plaque formation and As and heavy metal accumulation in two wetland plant species (Cyperus alternifolius Rottb., Echinodorus amazonicus Rataj), using As and heavy metals polluted paddy soil combined with three rates of RM application (0, 2%, 5%). The results showed that RM supply significantly decreased As and heavy metals accumulation in shoots of the two plants due to the decrease of As and heavy metal availability and the enhancement of the formation of iron plaque on the root surface and in the rhizosphere. Both wetland plants supplied with RM tended to have more Fe plaque, higher As and heavy metals on roots and in their rhizospheres, and were more tolerant of As and heavy metal toxicity. The results suggest that RM-induced enhancement of the formation of iron plaque on the root surface and in the rhizosphere of wetland plants may be significant for remediation of soils contaminated with As and heavy metals.     

Environmental Monitoring of Heavy Metal Status and Human Health Risk Assessment in the Agricultural Soils of the Jinxi River Area,China

Soil contamination with heavy metals is one of the main environmental concerns in China, mainly owing to rapid industrialization and mining activities in certain areas. The current study aimed at monitoring the levels of heavy metals in soils of the industrial areas along the Jinxi River and surrounding Lake Qingshan. In addition, a health risk assessment for humans in contact with these soils was also conducted. The results revealed that the soils of the studied areas were contaminated with Cr, Cu, As, Se, Cd, Pb, and Zn and that the industrial activities were the main source of soil contamination therein. Furthermore, soils of the sites adjacent to Lin’an city exhibited higher levels of heavy metals than the upstream and Lake Qingshan sites. Most of the studied heavy metals tended to concentrate in the fine soil fractions (PM100, PM10, and PM2.5). Calculation of the hazard index (HI) revealed that humans, especially children, have potential health risks. Moreover, As was found to contribute to more magnitude of cancer risks. Thus, we concluded that the unmanaged development negatively affects the Chinese environment and human health. Furthermore, fine fractions of soil particles should be considered for risk assessment.     

根际圈在污染土壤修复中的作用与机理分析

根际圈以植物根系为中心聚集了大量的生命物质及其分泌物,构成了极为独特的“生态修复单元”。本文叙述了根在根际圈污染土壤修复中的生理生态作用,富集、固定重金属,吸收、降解有机污染物等功能;菌根真菌对根际圈内重金属的吸收、屏障及螯合作用,对有机污染物的降解作用;根际圈内细菌对重金属的吸附与固定,对有机污染物的降解作用以及根际圈真菌和细菌的联合修复作用等,同时对可能存在的机理进行了分析,认为根际圈对污染土壤的修复作用是植物修复的重要组成部分和主要理论基础之一,并指出利用重金属超富集植物修复重金属污染土壤具有广阔的应用前景;筛选对水溶性有机污染物高吸收富集及其根 发泌能力强的特异植物,同时接种利于有机污染物降解的专性或非专性真菌和细菌可能会成为有机污染土壤植物修复研究的重要方向之一。     

河岸带土壤重金属元素的污染及危害评价

测定了金水河流域河岸带土壤部分重金属的全量和土壤水溶液的离子含量,运用污染指数和生态风险评价法对流域内土壤重金属进行评价.不同土地利用类型中,漫滩V、Cr含量最高(130.89、363.29 mg·kg-1),草地Ni、Pb、Ti、Mn、Zn、Cu含量最高(32.52、24.61、4378.09、1289.62、91.44、29.71 mg·kg-1).这主要是因为草地、漫滩能够有效吸附和沉积重金属,同时人类活动明显增加重金属生态危害.金水河流域河岸带土壤Cr、Pb、Zn均超过土壤环境质量标准(GB 15618-1995).与此同时,河漫滩白浆化棕壤和钙质粗骨土碳酸钙含量高,对Pb、Zn有较强的吸附和固定作用,能够有效吸附和沉积重金属;河漫滩人类干扰较重,造成其重金属含量较高.评价结果表明,流域河岸带内重金属环境污染达到中、重度污染,生态危害等级为轻微到中等级别.提高土壤腐殖质含量是减轻污染危害及增强土壤自净能力的重要措施.     

Individual and combined effects of cadmium and polycyclic aromatic hydrocarbons on the phytoremediation potential of Xanthium sibiricum in co-contaminated soil

Soil contamination with heavy metals and organic pollutants continues to cause major ecological damage and human health problems. Phytoremediation offers a highly promising technology for the recovery of sites contaminated with mixed pollutants. In this study, we performed a greenhouse experiment to investigate the individual and combined effects of cadmium (Cd) and polycyclic aromatic hydrocarbon (PAH) contamination on the growth of Xanthium sibiricum, and also the ability of this species to accumulate and remove Cd and to reduce PAHs over a period of 75 days. Our results demonstrated that individual or combined contamination by Cd and PAHs showed no significant differences to the control treatment except in the high Cd treatment. The reduction of PAH concentration in the soil with the passage of time was similar in the presence or absence of plants. At higher levels of Cd, the removal of pyrene decreased in both planted and non-planted soils; however, this effect might be due to the higher Cd content. Soil dehydrogenase and polyphenol oxidase activities showed that soil contamination did not have a significant effect on the removal of PAHs. Overall, our results suggest that X. sibiricum might be a suitable species for use in the phytoremediation of contaminated soils.     

Effects of Cd or/and Pb on soil enzyme activities and microbial community structure

Heavy metals could have long-term hazardous impacts on the health of soil ecosystems and adverse influences on soil biological processes. A study of Cd or/and Pb effects on soil enzyme activities and microbial community structure was undertaken with brown soil in a greenhouse for a period of 10 weeks. The experiment results showed that urease, acid phosphatase and dehydrogenase activities were significantly lower (p < 0.05) in Cd or/and Pb treatments than in control. Three enzyme activities decreased with the increasing metal concentrations. The effects of Cd and Pb combined on enzyme activities were higher than Cd or Pb alone. The soil microbial populations were far lower in heavy metal treatments than in control, and soil microbial populations under different heavy metals levels showed a significant difference (p < 0.05). The PCR-DGGE banding patterns confirmed that the addition of metals had a significant impact on microbial community structure.     

Using Soil Available P and Activities of Soil Dehydrogenase and Phosphatase as Indicators for Biodegradation of Organophosphorus Pesticide Methamidophos and Glyphosate

The heavy use of organophosphorus pesticides in northeastern China strongly affects the ecological functions and the quality of the soil environment. In this work, a 30-day soil incubation experiment was conducted to evaluate the potential of using soil available P and the activities of soil dehydrogenase and acid phosphatase as indicators of the application of methamidophos and glyphosate. Two kinds of unpolluted soils, phaiozem and burozem, were selected as the test soils. The higher application rate of organophosphorus pesticide to the two soils caused more release of PO₄ ^3? which finally entered the soil available P pool, suggesting that soil available P is one of the effective chemical markers for biodegradation of organophosphorus pesticides. Methamidophos exhibited a significant inhibitory effect on the activity of soil dehydrogenase. The extent of enzyme inhibition was almost positively correlated with the insecticide concentration, and the enzyme activity was gradually restored after day 15. However, its effect on soil acid phosphatase activity (stimulation or inhibition) seemed to be indefinite, and varied with the application rate, soil type, and incubation time. In the case of glyphosate, soil acid phosphatase activity was depressed significantly and the depressing extent could be a function of herbicide concentration and incubation time, but soil dehydrogenase activity showed an irregular variation with the herbicide application rate and soil type. In general, dehydrogenase activity was a good biochemical indicator for the biodegradation of methamidophos, but for glyphosate biodegradation the indicator was acid phosphatase activity.