污灌区盐分累积对污染土壤汞释放通量的影响  

A simulation study of mercury release fluxes from soils under different salinity levels in the wastewater-irrigated area

作　　者：郑顺安 习斌[1,2] 吴泽嬴 周玮 黄宏坤 郑向群 

机构地区：[1]农业部农业生态与资源保护总站,北京100125 [2]农业部资源循环利用技术与模式重点实验室,北京100125 [3]农业部环境保护科研监测所,天津300191

出　　处：《中国环境科学》2018年第3期1047-1053,共7页China Environmental Science

基　　金：国家自然科学基金项目(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;2017YFD0801401)

摘　　要：采用优化设计的动态通量箱,对不同盐分(Na Cl和Na_2SO_4)和盐度(0~5%)的盐渍化土壤土-气界面的汞交换通量进行动态监测,研究盐渍化对污灌区土壤汞和大气释放的影响.结果表明:(1)两种盐分类型对土壤Hg释放的影响呈相反趋势.与未发生盐渍化的对照土壤相比,随着Na Cl盐度梯度的上升,土壤Hg释放通量呈现上升趋势,5%盐度处理下,Hg通量均值与对照相比提高了48.94%;而随着Na_2SO_4盐度梯度的上升,土壤Hg释放通量呈现下降趋势,5%盐度处理下,Hg通量均值与对照相比降低了20.62%.(2)土壤盐分含量与土壤汞释放通量均值之间呈线性关系.对于Na Cl,含量x(g/kg)与汞通量y[ng/(m^2·h)]之间的模型为y=0.8258x+86.709(R^2=0.9734),对于Na_2SO_4,模型为y=-0.3354x+85.997(R^2=0.9581).从研究结果来看,高浓度的Na Cl环境对土壤汞释放通量有显著影响,土壤的盐渍化趋势会使汞释放及作物吸收风险更趋严重.This research was design to study the effects of salinity on mercury release from soils. Atmospheric mercury（Hg） was measured by using the optimized dynamic flux chamber to monitor the air/soil exchange of mercury from soilsspiked with NaCl and Na2SO4 at 0-5% level, respectively. The results manifested that, compared with the control soil （noexogenous salt spiked）, soil Hg emission flux showed a rising trend with the increase of NaCl salinity level which the Hgflux increased by 48.94% at the 5% salinity treatments, while soil Hg flux showed a decline trend with the increase ofNa2SO4 salinity level which the Hg flux decreased 20.62% at the 5% salinity treatments. Furthermore, there was a linearrelationship between the soil salt content and the mean soil Hg emission flux. The model between the content of x （g/kg ）and the Hg flux of y [ng/（m2·h）] is y = 0.8258x ＋ 86.709 （R2 = 0.9734） for NaCl, and the model is y = -0.3354x ＋ 85.997（R2 = 0.9581） for Na2SO4. The results illustrate that soil Hg emission flux can significantly affected by NaCl with highconcentration. The trend of salinization of soil will lead to more serious risk of Hg emission and crop absorption.

关 键 词：土壤 汞 盐分 释放 通量 

分 类 号：X53[环境科学与工程—环境工程]