摘要
根据全国土壤污染状况调查显示,全国土壤的环境状况总体不容乐观,耕地土壤环境质量令人担忧,已对粮食安全构成威胁。已有的研究工作多集中于土壤重金属的空间分布特征及污染源分析、重金属污染风险评估以及评估方法,但对于不同土壤深度重金属在耕地中的积累与剖面分布的变化及其生态风险分析相对较少。为研究四川省沐川县土壤剖面重金属分布特征和生态风险,本文在研究区选择三个不同地质背景区采集了土柱剖面样品开展相关工作。结果表明:样品中As、Cd、Hg、Pb、Ni、Cu、Zn七项指标中,除了Cu外,其余重金属元素含量都高于国家和四川省土壤背景值,表明这些元素在土壤中呈现不同程度地富集。土壤中7种重金属的浓度与土壤养分(氮、磷、钾),土壤有机碳和pH值存在相关性,如在玉米地剖面中,氮和磷与Cd呈显著正相关,相关系数分别为0.845、0.747。大量研究表明,磷肥中含有一定量的重金属。磷肥中重金属含量高低与磷矿及其来源有关,磷肥能够增加土壤Cd含量。土壤有机碳与Cd呈显著正相关,相关系数为0.934,其原因是土壤有机质对重金属的吸附作用,有机碳对土壤中重金属的保留起了重要作用。pH值与Cd呈显著负相关,相关系数为-0.964,随着pH值的增加,土壤对重金属离子的吸附会增加,从而导致土壤中活性重金属离子减少。土壤重金属之间存在显著的正相关关系,表明它们普遍存在同源性。采用地质积累指数(I_(geo))评价土壤重金属污染程度,并选取潜在生态风险指数(RI)评价其潜在生态风险,结果表明土壤中主要污染元素为Cd。生态风险指数显示,玉米地的潜在生态风险较大,其中Cd、Hg的生态风险较高,潜在生态风险指数(RI)随着剖面深度的增加而降低。当地应采取适当措施,加强对该地区污染的防治工作,避免对人体健康造成危害。
BACKGROUND:Soil is a precious resource for human survival and social development.The quality of the soil environment is impacted by a variety of issues due to the social economy’s rapid expansion,and the issue of heavy metal contamination in farmed land has garnered great attention globally.Heavy metals in soil pose a severe risk to the security of agricultural products and public health due to their persistence,latency,and ease of entry into the food chain.In recent years,many scholars have carried out research on soil heavy metal pollution and ecological risk assessment under different conditions such as natural conditions,industrial and mining industries and developed transportation in different regions.Zhou et al.[11]found that Xiong’an New Area was affected by the production activities of surrounding enterprises.The contents of As,Cd,Cu,Pb and Zn in some root soil samples exceeded the screening value standard for soil pollution risk of agricultural land(GB 15618—2018),and the exceeding ratios were 23.33%,96.67%,33.33%,33.33%and 10.00%,respectively.Song et al.[12]evaluated the characteristics of heavy metal pollution in the surface soil of Fuping County,Hebei Province,and found that As and Cd exceeded the acceptable carcinogenic risk level(As is 10−5,Cd is 10−6).Kumar et al.[10]collected data on heavy metalcontaminated soils in India from 1991 to 2018.The average Cd content of all soil types exceeded the limit values,and the potential ecological risk values of Cd were greater than 320,reflecting a higher ecological risk.For the heavily polluted soil,according to the different pollution situation in our country,the remediation measures are taken according to local conditions.However,due to the wide area of contaminated soil and the complex composition of pollution sources,the current soil remediation work still faces huge problems.OBJECTIVES:To study the vertical distribution characteristics of heavy metals in soil,the relationship between soil heavy metals and soil nutrient elements,as well as the d
作者
廖碧霞
沈文灵
贺灵
LIAO Bixia;SHEN Wenling;HE Ling(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China;Guilin University of Technology,Guilin 541006,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2023年第6期1203-1219,共17页
Rock and Mineral Analysis
基金
中国地质调查局地质调查项目(DD20190522-03,DD20221641-02)。
关键词
土壤
重金属
含量分布
污染评价
电感耦合等离子体质谱法
soil
heavy metals
content distribution
pollution assessment
inductively coupled plasma-mass spectrometry
