Ecological risk assessment of Cd and other heavy metals in soil-rice system in the karst areas with high geochemical background of Guangxi,China

查看全文 作　　者：Qiong [1]YANG;Zhongfang [1]YANG;Qizuan [2]ZHANG;Xu [1]LIU;Xiaoxiong [3]ZHUO;Tiansheng [3]WU;Lei [4]WANG;Xueji [5]WEI;Junfeng [6]JI

机构地区：[1]School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;[2]Guangxi Bureau of Geology&Mineral Prospecting&Exploitation,Nanning 530023,China;[3]Guangxi Institute of Geological Survey,Nanning 530023,China;[4]Geology Team No.4 of Guangxi Zhuang Autonomic Region,Nanning 530031,China;[5]Guangxi Geophysical Investigation Institute,Liuzhou 545005,China;[6]Key Laboratory of Surficial Geochemistry,Ministry of Education,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China

出　　处：《Science China Earth Sciences》索引2021年第64卷第7期,共14页

基　　金：supported by the National Key R&D Program of China(Granted No.2017YFD0800300);the Project of Geochemical Study on Selenium and Heavy Metal Elements in Central-Eastern Area of Guangxi,China(2015–2016);Study on the Genesis and Ecological Effect of Se,Ge and Cd in Soil of Guangxi,China(2017–2019);Ecological and Geochemical Survey and Study on the Heavy Metals in Typical Soil of Guangxi,China(2018–2019);Pollution Identification and Ecological Risk Assessment on Heavy Metals of Soil in the Area with High Geological Background in Guangxi,China(2017–2018);Geological Survey Achievement Conversion Foundation of China University of Geosciences(Beijing)。 摘　　要：Karst areas are widely distributed in China,and the soil derived in these areas is enriched with trace elements and has the typical characteristics of high geochemical background.Therefore,soil ecological risk has gradually attracted extensive attention.In this study,1090 sets of rice grains and paired rhizosphere soils were collected as research objects from the outcropped karst areas of carbonate rocks in Guangxi,and the concentration characteristics and influencing factors of heavy metals,such as Cd and As,in rice grains and the corresponding soils were studied.According to the Chinese Soil Environmental Quality Standard(GB 15618-2018),the proportion of karstic soil samples in Guangxi with heavy metal(As,Cd,Cr,Cu,Hg,Ni,Pb and Zn)concentrations that exceed the standard risk screening values was generally greater than that of surface soils in China or non-karstic soils in Guangxi.Notably,Cd and As were the most prominently enriched heavy metals in soils.According to the Chinese Food Safety Standard(GB 2762-2017),Pb in rice grains from the studied area did not exceed the standard;the exceedance rates of Cr,Hg,and inorganic As were only about 1%;and the exceedance rate of Cd was 12.5%.Soil Cd concentration increased gradually whereas the concentration and exceedance rate of Cd in rice grains decreased gradually with the increase of soil pH.Specifically,the exceedance rate of Cd in rice grains was only 4%when soil pH>6.5.The results indicated that the risk screening values of Cd element in the Chinese Soil Environmental Quality Standard are not satisfactorily applicable to the ecological risk assessment of Cd in karstic soils.Therefore,the recommended threshold values for the safe utilization and risk control of Cd in karstic soils was proposed so as to provide a basis for soil environmental quality hierarchization,pollution risk control and land safety zoning of agricultural land in karst areas in China. 关键词：Heavy metals SOIL Rice grain Ecological risk assessment Karst area in Guangxi High geochemical background

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Ecological risk assessment of Cd and other heavy metals in soil-rice system in the karst areas with high geochemical background of Guangxi,China

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