陕西农田土壤烟碱类农药污染现状及风险评估

Pollution status and risk assessment of nicotine pesticides in farmland soil in Shaanxi

对陕北、关中和陕南70个土壤样品进行4种烟碱类农药(吡虫啉、噻虫嗪、噻虫胺和啶虫脒)的残留测定,研究不同地区污染残留特征,并利用风险商值法进行生态风险评估。结果表明:(1)陕北农田土壤中噻虫胺的检出率(94.4%)较高,其生态风险主要以中等风险为主(占88.9%);关中农田土壤中吡虫啉的检出率(85.0%)较高,其生态风险主要以高风险为主(占80.0%);陕南农田土壤中噻虫胺的最大检出均值(184.32μg/kg)较高,吡虫啉和噻虫胺的高生态风险(分别占37.5%、18.8%)问题较突出,但土壤烟碱类农药实际生态风险还需考虑采样时间及作物生长状况的影响。(2)陕西农田土壤烟碱类农药含量与土壤pH、有机质、阳离子交换量等存在不同的显著相关性。

The residues of four nicotinic pesticides(imidacloprid,thiamethoxam,clothianidin and acetamiprid)were determined in 70 soil samples from northern,central and southern Shaanxi to study the characteristics of pollution residues in different regions,and their ecological risk assessment was conducted using risk quotient method.The results showed that:(1)the detection rate of clothianidin in farmland soil in northern Shaanxi was high(94.4%),and its ecological risk was mainly moderate(88.9%).Detection rate of imidacloprid in farmland soil in central Shaanxi(85.0%)was high,and its ecological risk was mainly high risk(80.0%).The maximum detection mean of clothianidin in farmland soil in southern Shaanxi(184.32μg/kg)was high,and high ecological risks of imidacloprid and clothianidin(accounting for 37.5%and 18.8%respectively)should be pay more attention.However,the actual ecological risks of soil nicotine pesticides need to consider the impact of sampling time and crop growth.(2)The content of nicotine pesticides in Shaanxi farmland soil had different significant correlations with soil pH,organic matter,cation exchange capacity,etc.