污灌区盐分累积对外源汞在土壤中甲基化的影响

发布时间：2018-06-01 21:27

本文选题：污灌区 + 汞　；参考：《中国环境科学》2017年11期

【摘要】：将汞同位素示踪剂~(199)Hg~(2+)(土壤背景含量的80%)加入不同盐分和盐度处理的盐渍化土壤中,利用多重标记稳定同位素示踪技术,研究盐分累积对外源汞在土壤中甲基化的影响.盐分种类为NaCl和Na_2SO_4,设置的盐度梯度为7个,添加质量分数为0%~5%.结果表明,外源199Hg2+加入土壤后,在培养期间,土壤中CH_3~(199)Hg~+生成量变化趋势总体呈S型曲线,表现出迟缓-最大速率-稳定3个阶段,用Logistic方程可以理想拟合盐处理下外源汞添加入土壤后生成甲基汞的动力学过程.在未添加盐分处理的对照土壤中,甲基汞最大生成量为0.698μg/kg,最大甲基化速率为0.217μg/(kg·d).NaCl处理下,随着盐度的增长,外源Hg进入土壤后汞甲基化程度总体呈现先增长后降低的趋势.0.2%~0.6%盐度下,甲基化程度显著提高,0.4%盐度下最高,最大生成量和最大甲基化速率分别达到3.589μg/kg和0.415μg/(kg·d).盐度在1%~2%时汞甲基化程度与对照比较接近,高盐度(5%)对汞甲基化有明显的抑制作用.Na_2SO_4处理下,当盐度水平超过0.2%时,会显著抑制外源汞加入土壤后甲基汞的生成.
[Abstract]:The mercury isotopic tracer (Hg2) (80% of soil background content) was added to the salinized soil treated with different salinity and salinity. The effect of salt accumulation on the methylation of exogenous mercury in soil was studied by means of multi-label stable isotope tracer technique. The salt species are NaCl and Na2SO4, the salinity gradient is 7, and the added mass fraction is 0%. The results showed that, after the addition of exogenous 199Hg2 to soil, the variation trend of Hg~ production in soil was S-shaped, showing three stages of slow-maximum rate-stability. The kinetic process of methylmercury formation by adding exogenous mercury into soil under salt treatment can be fitted perfectly by Logistic equation. The maximum yield of methylmercury was 0.698 渭 g / kg and the maximum methylation rate was 0.217 渭 g/(kg d).NaCl in the control soil without salt treatment. When exogenous Hg entered the soil, the methylation degree of Hg increased first and then decreased. Under the salinity of 0.6%, the degree of methylation was the highest under the salinity of 0.4%, and the maximum yield and the rate of methylation reached 3.589 渭 g/kg and 0.415 渭 g/(kg dl, respectively. The degree of mercury methylation was close to that of the control at the salinity of 1 ~ 2, and high salinity (5%) had obvious inhibitory effect on the methylation of mercury. Under the treatment of "Na _ 2SO _ 4", when the salinity level exceeded 0.2%, the formation of methylmercury was significantly inhibited after the addition of exogenous mercury to the soil.
【作者单位】：农业部农业生态与资源保护总站;农业部环境保护科研监测所;农业部资源循环利用技术与模式重点实验室;
【基金】：国家自然科学基金资助项目(41203084,41371463) 国家水体污染控制与治理科技重大专项(2015zx07103-007) 国家重点研发计划(2016YFD0201306,2016YFD0201200,2017YFD0801401)
【分类号】：X53

【相似文献】