典型沼肥灌施农田重金属的时间多尺度特征分析

作者	单位
马武生	扬州职业大学生物与化工工程学院, 江苏扬州 225009 江南大学环境与土木工程学院, 江苏无锡 214122 扬州市农产品智能测控与清洁生产工程技术研究中心, 江苏扬州 225009
李霖	扬州职业大学生物与化工工程学院, 江苏扬州 225009
薛梅	扬州职业大学生物与化工工程学院, 江苏扬州 225009
张占军	扬州职业大学生物与化工工程学院, 江苏扬州 225009

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中文摘要:

长期对农田进行沼肥灌施对土壤养分及重金属累积、迁移产生何种影响,尚缺乏系统的调查和研究。选取7—10年灌施沼肥的农田为研究对象,分析耕层土壤中Cu、Zn、Cr、Cd、Pb、Ni、Hg和As的全量及Cu、Zn各形态含量,并对污染水平及生态风险进行评价和预测。结果表明:持续灌施沼肥改变土壤的EC、pH等理化性质,造成P、K等营养元素和重金属Cu、Zn的显著累积。Cu、Zn平均积累速率分别为5.70~6.15、12.13~18.7 mg/(kg·年)。Cu和Zn含量之间具有显著相关性,表明它们同源。外源输入的稀释作用及形态转化使原土壤Cu、Zn赋存形态发生改变。综合污染指数法研究结果表明,养殖场土壤重金属均处于警戒水平。潜在生态风险指数法研究结果表明,养殖场土壤重金属危害程度整体表现为轻微生态危害。Cu、Zn年积累通量分别为10.26~11.07、21.83~33.66 kg/(hm²·年)。预测土壤中Cu、Zn浓度超出风险筛选值时间分别为10.19~11.01、9.16~14.14年。连续多年灌施沼肥将对土壤生态环境造成潜在风险。

英文摘要:

The effects of long-term farmland irrigation of biogas manure on soil nutrients and the accumulation and migration of heavy metals are still lacking in systematic investigation and research.The total amount of Cu,Zn,Cr,Cd,Pb,Ni,Hg and As and the contents of various species of Cu and Zn in the surface soil were analyzed with the farmland of 7-10 years irrigation with biogas manure as the research object.Moreover,the pollution level of the farmland soil was evaluated,and the ecological risk was predicted.The results showed that continuous irrigation of biogas manure changed soils physical and chemical properties,including EC and pH,which resulted in a significant accumulation of soil nutrients such as P,K and heavy metals such as Cu and Zn.The average accumulation rates of Cu and Zn reached 5.70-6.15 and 12.13-18.7 mg/(kg·a) respectively.The significant correlation between the concentrations of Cu and Zn indicated that they were homologous.The dilution of exogenous input and species transformation changed the morphological composition of Cu and Zn in the original soil.The comprehensive pollution index indicated that the sampling points of heavy metals in the farm were all at the alert level.The potential ecological risk index indicated that the hazard degree of heavy metals in farms was a slight ecological hazard (GB 15618-2018).The annual cumulative fluxes of Cu and Zn were 10.26-11.07 and 21.83-33.66 kg/(hm²·a) respectively.At this rate,the Cu and Zn concentrations in soil exceeded the risk sieving values by 10.19-11.01 and 9.16-14.14 years.Continuous irrigation of biogas manure for years will pose potential risks to the soil ecological environment.

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