Heavy Metal Contamination in Farmland Soil and Bioremediation Measures: A Case Study of the Mining Area in Shaoguan

With the rapid development of mining,the soil heavy metal contamination is increasingly serious in Shaoguan,directly affecting the production of crops. This paper analyzes the farmland soil heavy metal contamination in the mining area of Shaoguan and the causes of heavy metal contamination in recent years,brings forward the bioremediation measures to control soil heavy metal contamination,and points out the development direction of bioremediation in farmland soil heavy metal contamination in the mining area.

Effects of heavy metal pollution on farmland soils and crops:A case study of the Xiaoqinling Gold Belt,China

This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to the geochemical analysis results of the soils observed in the gold belt,the soils are most highly enriched in Pb,followed by Cr,Cu,and Zn.Furthermore,they are relatively poor in Hg,Cd,and As.It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt.As for the crops(such as corn and wheat)in the gold belt,Zn and Cu are the most abundant elements,followed by Pb and Cr.Meanwhile,Hg,Cd,and As were found to have relatively low concentrations in the crops.The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general.Compared to the aeolian loess soils and the crops therein,heavy metals are more enriched in diluvial and alluvial soils and the crops therein.As shown by relevant studies,the Hg,Pb,Cd,Cu,and Zn pollution are mainly caused by mining activities.Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations.Furthermore,wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils.The Hg pollution in soils leads to Hg accumulation,increasing the risk of Hg uptake in crops,and further affecting human health.This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas.

Advances in Cotton Tolerance to Heavy Metal Stress and Applications to Remediate Heavy Metal-Contaminated Farmland Soil

Heavy metal-contaminated soil is one of the major environmental pollution problems of agricultural production and human health in the world.Remediation of heavy metals in soil is one of the most popular research subjects.Different remediation strategies have been reported to remove heavy metals from contaminated soil,among which phytoremediation is the most important one.Compared with other major crops,cotton shows the strongest and most widespread resistance to abiotic stresses,such as heavy metals.Although heavy metal stress adversely affects the growth and development of cotton,cotton possesses a set of sophisticated stress-resistance strategies.As the main product of cotton is nonedible fibers,which have a large biomass and strong heavy metal absorption and enrichment capacities,cotton is an ideal crop to restore heavy metal-contaminated soils and has unique advantages in terms of both ecological and economic benefits,with great application prospects.In this review,based on domestic and foreign research results in recent years,the effects of heavy metals on cotton growth and product quality were analyzed,the heavy metal absorption,accumulation,translocation and enrichment characteristics of cotton plants were summarized,and the adaptation and tolerance mechanisms of cotton to heavy metals were explored.Furthermore,the view that cotton is an effective crop to remediate heavy metal pollution in farmland soil has been proposed,and popularization and application suggestions for planting cotton to repair heavy metal pollution have been put forward to provide a reference for the comprehensive evaluation of the economic feasibility of cotton to repair heavy metal pollution in farmland soil.

Contamination and risk assessment of heavy metals in farmland soils of Baghrash County, Xinjiang, Northwest China

Soil pollution significantly reduces environmental quality.In this study,farmland soil samples were collected from 25 sites in Baghrash County,Northwest China;and the concentrations of eight heavy-metal elements(arsenic,As;cadmium,Cd;chromium,Cr;copper,Cu;manganese,Mn;nickel,Ni;lead,Pb;zinc,Zn)were determined by standard methods.The spatial distribution,contamination level,and ecological risk stature of heavy metals were analyzed based on GIS technology,the Geo-accumulation Index(Igeo),the Pollution Load Index(PLI),and the Potential Ecological Risk Index(RI).Results indicated that(1)The average concentrations of Cd exceeded 12.12 times the allowed national standard for soil environmental quality of China.The average concentrations of Cd,Cr,Ni,Pb,and Zn exceeded the background values of irrigation soils in Xinjiang by 60.58,1.25,1.50,4.95,and 5.10 times,respectively.(2)The pollution order of the average value of Igeo for heavy metals was ranked as Cd>Zn>Pb>Ni>Cr>Cu>As>Mn.The individual potential ecological risk index for heavy metals was ranked in the order of Cd>As>Ni>Cu>Pb>Cr>Zn.The average PLI for the study area showed a heavy pollution level,while the average RI showed a considerable ecological risk stature,as compared to the classification standard.(3)The spatial distribution patterns of eight heavy metal elements were substantially heterogeneous.The moderately polluted areas with moderate potential ecological risks were distributed in the southern parts of the study area,whereas the heavily polluted areas with considerable potential ecological risks were distributed in the northern parts.Overall,it was observed that Cd contributed most to the PLI and RI of the farmland soils in Baghrash County.The pollution risk of Cd should be a major concern,and human activities in the region should be cautious.

Farmland Soil Heavy Metal Pollution and Control Measures

Soil pollution has been considered as one of the main environmental problems in the world nowadays. The source of soil heavy metal pollution in farmland, the effect of heavy metal pollution on soil quality in farmland, growth of crops, quality of agricultural products and the effects of heavy metal pollution on human health were discussed in this paper. The heavy metal pollution control measures were introduced, including physical and chemical regulations, phytoremediation and agroecological restoration measures. The future research perspective was also discussed in this paper.

Preliminary Study on Heavy Metal Pollution Status of Farmland Soil at Two Sides of Cheng-Guan Expressway

The heavy metal content of the farmland soil at two sides of Cheng-Guan Expressway is measured to make a preliminary evaluation on its heavy metal pollution status.After digestion and volume fixation of the soil samples collected,measure the Cu,Zn,Cd,Pb and Cr content with atomic absorption spectrophotometry and evaluate the measured data according to Level Two of National Soil Environmental Quality Standard to obtain the contamination status.Cu,Zn and Cd content of the farmland soil for sections of Cheng-Guan Expressway goes beyond Level Two of National Soil Environmental Quality Standard,while the Pb and Cr content meets Level Two of National Soil Environmental Quality Standard.Pb and Cr content of the farmland soil at two sides of Cheng-Guan Expressway is in safe state,while the Cu,Zn and Cd content is in a mild contamination state.Cu,Zn and Cd are the main pollution elements.

Effects of Land Use Patterns on Soil Heavy Metal Contents

Through sampling in farmland and analysis in laboratory,the contents and the pollution level of Cr,Cu,As,Pb,Zn in different soils were studied. The comparative result showed that the As in all soil samples are lower than the mean value of Shaanxi and whole nation,the Cr in lower half soil samples are higher than the mean value of Shaanxi and whole nation,the Cu and Zn in majority soil samples are higher than the mean value of Shaanxi and whole nation,and the Pb in all soil samples is higher than the mean value of Shaanxi and whole nation. The single factor pollution index and multi-factor pollution index method were used to evaluate the soil pollution. According to Soil Environmental Quality Standard,the studied soils were at unpolluted degrees,the soils were clear,the quality of soil adapt to the crop growth,and not affect the quality of agricultural product.

Remediation Technology for Combined Pollution of Lead and Cadmium in Farmland Soil

At present,the problem of heavy metal pollution in farmland in southern China is serious. Especially,the cadmium and lead are two heavy metal elements with serious pollution and great harm to human body. This paper reviewed some common methods and materials used in the control of cadmium and lead pollution in farmland soil. Then,it discussed the problems in the repair of cadmium and lead pollution in farmland soil. It came up with the future research direction,to provide references for remediation of lead and cadmium pollution in farmland soil.

Distribution Characteristics of Pb and Its Ecological Risk in Different Farmland Soils of Changchun Suburb

Pb in the farmland surface soil of Changchun suburb was taken as the main research object. The field research and laboratory analysis were used to investigate Pb content, spatial distribution characteristics and its ecological risk in different farmland soils. The results showed that Pb content was during 18.85 - 41.34 mg/kg in farmland soil of Changchun suburb, and was higher than the background value of Jilin Province at 90% of the sampling sites. The spatial distribution of Pb content in farmland soil had obvious geographical features, and Pb content in southwest and northeast soils was higher. The high-content areas were relatively concentrated, and Pb content gradually reduced from the high-content island- shape center to its surrounding. The soil Pb contents in paddy field, dry field and vegetable field had insignificant difference with the background value, indicating that Pb accumulations in dry field, paddy field and vegetable field were not significant. The order of Pb content in different land use types was showed as follows： vegetable field 〉 dry field 〉 paddy field. Pb pollution of all samples belonged to light pollution. The average potential ecological risk of soil Pb in different land use types presented the following order： vegetable field 〉 dry field 〉 paddy field.

丹江口库区沿岸农田土壤重金属分布与来源解析

丹江口水库作为南水北调中线水源地,库区沿岸土壤重金属分布特征直接影响水库水质安全。为研究丹江口水库沿岸农田土壤重金属的污染特征及来源,测定了As、Cd、Cu、Pb、Hg、Ni、Zn和Cr等8种重金属。采用地质累积指数和富集因子对土壤污染状况进行评价,并运用相关性分析及主成分分析展开溯源。结果表明:研究区8种重金属(除2个样品的总As浓度外),其他样品重金属浓度均未超过《土壤环境质量农用地土壤污染风险管控标准(试行):GB 15618—2018》筛选值。Hg富集程度最高,均有4%采样点处于中度富集状态(1<I_(geo)≤2)和重度富集状态(2<I_(geo)≤3)。整个库区农田土壤重金属As、Cd、Cu、Pb、Hg、Ni、Zn和Cr的无污染至轻微污染区均>92%,As、Cd、Hg和Cr的中度以上污染区分别为4%、4%、6%和4%,仅Hg有2%区域属重度污染。空间上,8种重金属分布差异显著,库区农田土壤呈轻度富集趋势。来源解析发现,As、Cu、Ni和Zn主要受生活污染源和工业污染的混合影响,Pb以交通源为主,Cd主要来源于农业污染源,Hg受大气沉降源的污染,而Cr主要来源为成土母质自然源输入,其贡献率分别为44.655%、15.376%、13.093%、11.178%、8.386%。

中国农田土壤重金属污染的人体健康风险评估:研究进展与展望

农田土壤重金属污染对食品安全和人体健康构成巨大的威胁。重金属主要通过经口摄入土壤、吸入土壤颗粒、皮肤接触和食物链摄取等暴露途径进入人体,其中经口摄入重金属污染土壤和农产品是主要的暴露途径。人体健康风险评估在农田土壤质量分类和风险管控中起着重要作用。因此,梳理了中国农田土壤重金属污染的人体健康风险评估的发展状况,介绍了人体健康风险评估的基本流程和评估技术,论述了影响人体健康风险评价准确性的主要因素及优化措施。在农田土壤重金属健康风险评估中,应加强耦合污染源识别技术、重视食物消费暴露途径、精准识别不同敏感受体、本土化敏感受体的暴露参数、纳入重金属的生物可给性,同时提高农田土壤重金属健康风险评估的准确性。未来可从加强应对健康风险评估过程不确定性的技术方法、考虑各种饮食的暴露途径和建立本土化的重金属毒性标准数据等多方面深化农田土壤重金属健康风险评估,以期推动中国农田土壤重金属人体健康风险评估的理论和技术发展。

基于波谱响应特征的雄安新区农田土壤重金属含量反演

分析并监测雄安新区农田土壤污染状况,对于保障粮食安全、建设绿色雄安具有重要意义。该研究以雄安新区为研究区,基于多源遥感数据珠海一号(Zhuhai-1)OHS数据、哨兵二号(Sentinel-2)L2A级数据的波谱响应特征及实地测得的农田土壤重金属含量数据,在对土壤重金属含量单因子与多因子污染评价的基础上,筛选出3种超标的农田重金属元素铅(Pb)、铜(Cu)、锌(Zn),采用偏最小二乘回归方法(partial least squares regression,PLSR)建立农田土壤重金属含量反演模型。利用Zhuhai-1提取土壤样本点的原始光谱反射率以及4种变换后的光谱反射率,Sentinel-2提取7种对重金属胁迫敏感的植被指数,将其与3种土壤重金属含量作相关性分析,筛选出敏感波段与植被指数,即波谱响应特征,构建土壤重金属含量反演模型。结果表明,3种模型整体反演精度较为优良,Pb含量反演模型决定系数(determination coefficient,R^(2))为0.490,均方根误差(root mean squared error,RMSE)为4.66 mg/kg,平均绝对值误差(mean absolute error,MAE)为1.92 mg/kg;Cu含量反演模型R^(2)为0.491,RMSE为16.85 mg/kg,MAE为3.69 mg/kg;Zn含量反演模型R^(2)为0.664,RMSE为20.63 mg/kg,MAE为9.36 mg/kg。将该模型应用于雄安新区农田区域,得到大部分农田土壤中Pb含量均未超过风险筛选标准,在研究区西南部、西部部分区域Cu含量超过土壤污染风险筛选值,同时在研究区西部、西南部Zn污染较严重,雄安新区东南部部分农田有Zn零星分布,其他区域Cu和Zn含量未超过国家土壤污染风险管控值。因此,利用多源遥感数据波谱响应特征反演土壤重金属Pb、Cu和Zn含量,能够快速准确地实现对雄安新区土壤重金属污染情况的调查,同时为大面积土壤重金属含量监测提供解决方案。

农田土壤重金属污染现状与安全利用技术研究进展

重金属污染农田直接影响粮食安全和农业可持续发展。安全利用技术主要通过降低土壤中重金属的生物有效性,以减少作物对重金属的吸收累积和消减重金属进入食物链的风险,其对解决我国重金属污染农田有效利用和保障粮食安全生产具有重要意义。因此,本文首先分析了农田土壤重金属污染成因与现状,然后综述了不同安全利用技术,如农艺调控措施(包括低累积作物品种筛选、水肥管理及间作或轮作耕作方式)、原位钝化改良和叶面阻控技术的研究进展,最后提出了强化重金属污染农田土壤安全利用研究及应用的对策。

铜选冶厂周边农田土壤重金属污染特征及来源解析

为分析云南某铜选冶厂周边农田土壤重金属污染特征及来源,通过测定农田土壤中重金属(Cu、Zn、Cr、Ni、Pb、Cd、As、Hg)的含量,采用污染负荷指数、地累积指数及潜在生态危害指数法评价农田土壤重金属污染特征,并结合相关性分析和PMF模型对土壤重金属来源进行分析.结果表明:研究区土壤中Cr、As、Pb、Hg 4种重金属元素的平均含量均高于云南省土壤背景值;污染负荷指数处于轻微污染;地累积指数中As(0.92)>Hg(-0.05)>Cr(-0.41)>Pb(-0.52)>Cu(-1.05)>Zn(-1.20)>Ni(-1.21)>Cd(-3.23),As元素属于轻度累积,其余重金属均为无累积;潜在生态风险单项指数中除Hg元素达到中等生态风险,其余7种重金属元素均为轻微生态风险,研究区整体处于轻微生态风险.土壤重金属来源分析中PMF模型解析5个因子,贡献率分别为14.8%、16.1%、15.3%、26.6%和27.2%.其中As元素主要为工业活动源,Cu、Zn、Cr、Ni元素主要为土壤成土母质源、Cd元素主要为农业活动源、Pb元素主要为交通源、Hg元素主要为化石燃料源.

朔州东部农田土壤–农作物重金属富集及健康风险评价

为研究重金属在农田土壤-作物之间的累积性及人群健康风险,采用富集因子(EF)、地累积指数(I_(geo))和潜在生态危害指数(RI)等指标对山西省朔州市东部三县市(山阴县、应县、怀仁市)131个样点农田土壤-作物系统(玉米、高粱和大豆)中重金属的含量、来源及富集程度进行调查,并采用EPA推荐的风险评估模型对人群健康风险进行了评估.结果表明:1)研究区土壤中8种重金属(Cd、Cr、As、Hg、Pb、Cu、Zn、Ni)含量均未超过《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618—2018)中农用地土壤污染风险筛选值;而Cr、Hg、Pb的平均含量分别是研究区背景值的1.20倍、6.26倍和1.33倍.2)研究区土壤中Hg元素为显著富集,其余重金属无富集.地累积指数分级结果表明,土壤中Hg呈中度污染,其余为无污染.潜在生态危害指数结果表明研究区为中度污染水平.3)主成分分析结果表明,研究区Ni、Cr、Zn、Cu主要来源于“自然来源”,Hg主要来源于“直接工业源”,As、Pb主要来源于“大气沉降-工业源”,而Cd主要来自“农业来源”.4)8种重金属对儿童的非致癌风险高于成人.研究区Pb对儿童和成人均无致癌风险,Cd和As对儿童和成人的致癌风险均处于可接受范围内,而Cr、Ni是主要致癌风险因子.

农田土壤重金属外源识别及安全利用技术筛选——以宜宾市筠连县部分区域为例

【目的】基于农田土壤重金属污染外部来源途径的识别结果,筛选出钝化剂-低积累作物品种耦合的镉污染农田绿色修复与安全利用技术,以期为农田土壤重金属污染防控提供参考依据。【方法】以四川南部宜宾市筠连县部分乡镇为研究区域,监测该区域内大气沉降、肥料使用、灌溉水及底泥中重金属含量从而计算不同途径的农田土壤重金属输入通量,并选择具有代表性的JL镇利用大田试验开展钝化剂、重金属镉低积累蔬菜和水稻品种筛选。【结果】2019—2020年研究区域农田土壤中汞、砷、铅和锌的主要输入途径为大气沉降,所占比例分别为99.99%、75.88%、90.57%和84.82%;镉、铬和镍的主要输入途径为肥料,所占比例均为100.00%;铜的主要输入途径为灌溉水,所占比例为93.66%。JL镇镉污染农田土壤中施用铁锰肥钝化剂(硫酸亚铁750 kg/hm^(2)+硫酸锰75 kg/hm^(2))对降低水稻籽粒中镉的效果最佳,归因于土壤微量元素的补充对肥力的改善作用,而钝化剂复配(3000 kg/hm^(2))处理下水稻籽粒中镉含量最高。镉低积累蔬菜和水稻品种筛选结果表明九斤萝卜和川康优6276是该地区最适宜种植的蔬菜和水稻品种,收获后可食用部分重金属镉含量均符合食品安全国家标准。【结论】在研究区域除应选用符合国家标准的肥料并注意防控大气沉降污染外,同时建议推广使用铁锰肥、腐殖酸和磷肥钝化材料,并种植九斤萝卜蔬菜和川康优6276水稻品种以保障农产品质量安全。

油菜、龙葵、苎麻对镉、砷复合污染农田土壤的修复效果

以油菜、龙葵、苎麻为试材,采用室内盆栽试验研究了油菜、龙葵、苎麻对耕地土壤中Cd和As的吸附效果和富集转移效应,并施加沼泽红假单胞菌和黑曲霉两种微生物,探讨了微生物对油菜、龙葵和苎麻净化重金属污染土壤的应用潜力。结果表明,油菜和龙葵对土壤中重金属Cd的吸附效果较好,表现出富集特性,而苎麻植株对Cd的吸收效果较差。其中油菜植株体内Cd含量大小表现为油菜茎杆>油菜根>油菜子,龙葵植株体内Cd含量大小表现为龙葵茎>龙葵果>龙葵根;油菜、龙葵、苎麻对土壤中As吸附效果均较差;沼泽红假单胞菌和黑曲霉两种微生物对促进油菜、龙葵和苎麻吸收土壤中Cd和As的作用均较小。油菜更适宜用作Cd重金属污染土壤的修复植物。

自然复合污染条件下小白菜对镉汞吸收的品种差异研究

为探明自然轻度镉(Cd)、汞(Hg)复合污染对不同品种小白菜生长及重金属吸收的影响,采用盆栽和田间试验,测定小白菜可食部的生物量、维生素C含量、可溶性蛋白含量和Cd、Hg含量。结果表明,所测指标在21个品种间均存在显著差异,Cd含量为0.185~1.25 mg/(kg·DW),Hg含量为8.56~238µg/(kg·DW)。在盆栽和田间条件下,2个品种Cd富集系数小于1,而所有品种Hg富集系数均小于1。相关性分析显示,可食部生物量、可溶性蛋白含量、Cd含量以及Hg含量之间均无显著相关关系。供试21个品种在该轻度复合污染农田种植不存在安全风险,其中‘奶油小白菜’是安全性最高的品种。

珠三角典型重金属污染农田土壤调理剂筛选田间试验研究

为探究不同土壤调理剂对农田土壤和稻米中重金属含量的影响,筛选适宜的耕地污染修复治理方法,实现精准选用调理剂进行安全生产的目的,本试验分析了市售6种土壤调理剂在4种不同早晚造用量条件下对土壤pH值、土壤重金属总量、土壤有效态Cd含量、稻米重金属含量和稻米产量的影响。结果表明:施用6种调理剂均可提高土壤pH值,6种调理剂对土壤pH值的提升效果排序为金葵子>粤田>营养阻控剂>天象>铁基生物炭>铁改性木本泥炭,pH增幅为3.2%~24.3%。施用6种土壤调理剂不会额外增加土壤中各重金属总量,且均能降低土壤中有效态Cd含量,降低有效态Cd效果排序为粤田(3、2、1、4)>铁基生物炭(3)>天象(2、4、3)>营养阻控剂(1、3)>金葵子(1),降幅达25.0%~58.3%。6种土壤调理剂均能降低早造稻米中Cd含量,降Cd效果排序为天象(2)>天象(1)>天象(3)>铁改性木本泥炭(1)>铁改性木本泥炭(2)>天象(4)>铁基生物炭(4)>粤田(1),降幅为47.8%~67.5%,降低后稻米中Cd含量均低于《食品安全国家标准》(GB 2762—2022)中糙米Cd限量标准0.2 mg·kg^(-1)。施用6种土壤调理剂对水稻产量无显著影响,产量均未低于对照组的90%,满足安全生产要求。针对珠三角典型重金属污染农田,推荐按天象(2)的方式进行处理,即早造每公顷施加2250 kg天象调理剂、晚造每公顷施加2250 kg天象调理剂,该方式可显著提高稻田土壤pH值、降低稻田土壤中有效态Cd含量、降低稻米中Cd含量,且不影响稻米产量。

公路沿线农田重金属污染研究

随着公路里程的日益增加和公路网的加密,公路交通已成为公路两侧土壤重金属污染的重要来源。中国人均耕地面积较少,公路两侧仍存在着大量的农田,种植着不同的农作物。研究表明,公路交通已对公路两侧的农田土壤和农作物造成不同程度的污染,对农产品的质量和安全产生较大的威胁。该文系统阐述了公路沿线农田土壤和农作物的重金属污染现状,以及二者之间的关系,深入分析了影响公路沿线土壤重金属空间分布的因素,对公路沿线农田重金属污染的研究方向提出展望,以期为路侧农田土壤重金属的污染防治提供思路与方向。