广东大宝山矿区附近农田土壤镉元素输入通量研究

Cadmium Input Flux in Farmland Soil Near the Dabaoshan Mining Area of Guangdong Province

为了解大宝山矿区附近农田土壤镉元素的污染来源及其特征,计算获取了该区大气干湿沉降、化肥和灌溉水输入通量。结果表明,研究区输入通量总量平均为5.92 g/(hm^2·a)。镉元素的三种输入途径中,灌溉水的输入通量最高,平均值为3.88 g/(hm^2·a);大气干湿沉降输入通量次之,平均值为1.97 g/(hm^2·a);化肥输入通量最少,为0.07 g/(hm^2·a),三者对土壤镉污染贡献率分别为65.53%、33.27%和1.21%。研究区农田土壤镉污染的主要来源是灌溉水。在不考虑农田土壤Cd输出的情况下,当前外源输入镉的平均通量可引起表层土壤镉的质量分数每年升高2.63μg/kg。

In order to understand the sources and characteristics of cadmium pollution in farmland soil near Dabaoshan Mining Area,Guangdong Province,the atmospheric dry and wet deposition,chemical fertilizer and irrigation water input fluxes were calculated.The results show that the total input flux in the study area is 5.92 g/(hm^2·a)on average.Among the three ways of cadmium input,irrigation water has the highest input flux,with an average of 3.88 g/(hm^2·a);atmospheric dry and wet deposition has the second,with an average of 1.97 g/(hm^2·a);chemical fertilizer has the lowest input flux,with an average of 0.07 g/(hm^2·a),and their contribution rates to soil cadmium pollution are 65.53%,33.27%and 1.21%,respectively.The main source of cadmium pollution in farmland soil in the study area is irrigation water.Without considering the output of cadmium from farmland soil,the current average flux of exogenous cadmium can increase the cadmium content of surface soil by 2.63μg/kg per year.