土壤湿度对重金属污染物的生物有效性和生态毒性影响  

Impact of Soil Moisture on the Bioavailability and Ecotoxicity of Heavy Metals

作　　者：龚冰 王徐鹏 应蓉蓉 仇浩 GONG Bing;WANG Xupeng;YING Rongrong;QIU Hao(State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control,Nanjing 210042,China;School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Nanjing Institute of Environmental Sciences,MEE,Nanjing 210042,China)

机构地区：[1]国家环境保护土壤环境管理与污染控制重点实验室,南京210042 [2]上海交通大学环境科学与工程学院,上海200240 [3]生态环境部南京环境科学研究所,南京210042

出　　处：《生态毒理学报》2025年第1期48-61,共14页Asian Journal of Ecotoxicology

基　　金：国家自然科学基金青年项目(42407377);国家环境保护土壤环境管理与污染控制重点实验室开放课题;中国博士后科学基金(2021M702119)。

摘　　要：土壤湿度的波动可能通过改变土壤的物理、化学和生物学性质显著影响重金属在土壤中的形态、转化及归宿,对农产品安全、动物和人体健康产生潜在风险。本研究以多重金属污染土壤为介质,典型土壤岗哨动物线蚓(Enchytraeus crypticus)为受试生物,探究了不同土壤湿度下,线蚓对污染土壤中Cd、Cr、Cu和Zn的动态累积和毒性响应过程。结果显示,土壤湿度改变了土壤中重金属的有效态浓度及线蚓对重金属的累积速率,进而影响了线蚓的存活率与繁殖率。具体而言,与较高的土壤湿度(80%田间持水量)相比,较低的土壤湿度(50%田间持水量)条件下土壤中Cd、Cr、Cu和Zn的有效态浓度含量普遍更低,这可能和不同土壤湿度条件下土壤中CO_(2)浓度有关。线蚓体内重金属累积量与暴露时间呈正相关关系,在不同土壤湿度下,线蚓体内Cd和Zn含量差异明显,在50%田间持水量下,线蚓体内Cd和Zn的浓度分别为17.2 mg·kg^(-1)和458 mg·kg^(-1),而在80%田间持水量下则高达39.5 mg·kg^(-1)和601 mg·kg^(-1),即土壤湿度越大体内累积的重金属含量越多,但土壤湿度对线蚓体内Cr和Cu影响不大。线蚓的存活率和繁殖率随土壤湿度的增加而降低,这与体内重金属浓度的增加有关。研究结果增进了对土壤重金属在湿度变化条件下形态转化规律及其内在机制的认识,对评估全球变暖背景下农田土中重金属复合污染风险具有重要意义。Soil moisture fluctuations can significantly affect the speciation,transformation,and fate of heavy metals in soil by altering its physical,chemical,and biological properties.This poses potential risks to the safety of agricultural products as well as animal and human health.Herein,the dynamic accumulation and toxic response of a typical soil sentinel species,Enchytraeus crypticus,to heavy metals in composite heavy metal-contaminated soil were investigated under different soil moisture conditions.The results indicated that soil moisture affected the bioavailable concentration of metals in the soil and the accumulation rate of heavy metals by E.crypticus,which subsequently affected their reproductive rates.Specifically,compared to higher soil moisture(80%field water holding capacity),lower soil moisture(50%field water holding capacity)generally resulted in reduced concentrations of bioavailable cadmium(Cd),chromium(Cr),copper(Cu),and zinc(Zn)in the soil.This may be related to variations in CO_(2)concentration in the soil under different soil moisture conditions.Furthermore,there was a positive correlation between exposure time and heavy metal concentrations in E.crypticus.Significant differences were observed in the concentrations of Cd and Zn in earthworms under different soil moisture levels.Under 50%field water holding capacity,the concentrations of Cd and Zn in E.crypticus reached up to 17.2 mg·kg^(-1)and 458 mg·kg^(-1),respectively;whereas under 80%field water holding capacity,they increased to 39.5 mg·kg^(-1)and 601 mg·kg^(-1),respectively.However,there were no significant differences in Cr and Cu concentrations under the two soil moisture conditions.As soil moisture levels increased,the reproductive rates of E.crypticus in both types of soil decreased,attributed to higher soil moisture resulting in higher concentrations of heavy metals in the organisms.The results deepen our understanding of the speciation transformation and mechanisms of heavy metals in soils under varying moisture contents.This resear

关 键 词：湿度变化 重金属复合污染 线蚓 生物有效性 动态毒性 

分 类 号：X171.5[环境科学与工程—环境科学]