摘要
采集弱碱性污灌区玉米地土壤,分析了土壤重金属含量特征,综合比较EDTA、NH4OAc、DTPA、CaCl2等4种不同提取剂对弱碱性土壤重金属有效态的提取能力,采用改进的BCR法测定了土壤重金属各形态含量,并分析不同提取剂浸提的重金属有效态含量与土壤理化性质、重金属全量以及各形态之间的相关关系.结果表明,调查区土壤pH值为7.70—8.52,属于弱碱性土壤.采用地累积指数与Hakanson潜在生态危害指数综合评价发现,土壤重金属Cd污染程度较为严重,具有很强的潜在生态风险,而Cu、Zn、As属轻度污染,生态风险程度较低.不同提取剂对弱碱性土壤重金属浸提能力存在明显差异,最高为EDTA,依次是DTPA、NH4OAc和CaCl2.土壤Cd、Zn可交换态和可还原态比例较高,具有一定的潜在生物有效性,而重金属Cu、As赋存状态主要以残渣态和可氧化态为主.不同提取剂浸提的重金属有效态含量与重金属全量和各形态含量之间的关系较为密切,其中DTPA提取态重金属含量与土壤重金属全量均呈显著(P<0.05)或极显著正相关关系(P<0.01).
Weakly alkaline maize soils in wastewater irrigated areas of Tianjin were collected to analyze the concentration of heavy metals. 4 extractants such as EDTA, NH4OAc, DTPA and CaCl2 were applied to determinate the extracted efficiency of heavy metals. A modified BCR sequential extraction procedure was used to study the speciation distributions of heavy metals. Correlation relationships among the content of available heavy metals by different extractants and soil physicochemical properties, the total content of heavy metals, and fraction of heavy metals were investigated. The results showed that the pH value of the test soil was 7.70—8.52, being weakly alkaline soil. The results of geo-accumulation index and Hakanson potential ecological index demonstrated that soil was seriously contaminated by Cd, and the potential ecological risk was higher, while for the contamination of Cu, Zn, and As, it was lightly and lower levels of potential ecological risk. The extracted efficiency of heavy metals by different extractants was significantly different, the highest extraction ability was EDTA, followed by DTPA, NH4OAc and CaCl2. The proportion of exchangeable and reducible fraction of Cd and Zn in soils was higher, showing a certain potential bioavailability. However, Cu and As were mainly associated with the oxidizable and residual fraction. A close relationship was found among the extracted content of heavy metals by different extractants and the total content of heavy metals, and the speciation distributions of heavy metals. There was an extremely(P<0.01) or obviously(P<0.05) positively correlation between the extracted content of heavy metals by DTPA and the total amount of heavy metals.
作者
孙彤
纪艺凝
李可
马文艳
谢厦
孙约兵
SUN Tong;JI Yining;LI Ke;MA Wenyan;XIE Sha;SUN Yuebing(College of Resources and Environment,Northeast Agricultural University,Harbin,150030,China;Key Laboratory of Original Agro-Environmental Pollution Prevention and Control,Ministry of Agriculture and Rural Affairs,Tianjin Key Laboratory of Agro-Environment and Agro-Product Safety,Agro-Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin,300191,China)
出处
《环境化学》
CAS
CSCD
北大核心
2020年第9期2469-2478,共10页
Environmental Chemistry
基金
国家重点研发计划项目(2018YFD0800305)
天津市自然科学基金重点项目(17JCZDJC34200)资助
关键词
重金属
弱碱性
有效态
提取剂
生态风险评价
heavy metals
weakly alkaline
available state
extractants
ecological risk assessment
