我国东北地区地表水酸化现状

Current Status of Surface Water Acidification in Northeast China

2011年8月对我国东北地区东部的溪流进行采样调查,以评价地表水的酸化现状.通过对采集的33个水体pH值和酸中和容量(ANC)的分析发现,只有长白山上少数溪流的pH值低于6.0,而所有采样水体的ANC均高于0.2 meq.L-1,说明该地区尚未大面积发生地表水酸化问题.离子浓度分析结果表明,HCO3-是水体中最主要的阴离子,而SO24-浓度往往小于150μeq.L-1,NO3-浓度更是远低于SO24-,这说明该地区酸沉降污染较轻.但是,东北地区广泛分布着风化速率较低的酸性森林土壤,导致一些水体缓冲酸沉降的能力较弱,水体酸化的可能性仍然存在.以此类推,东北亚目前的酸沉降水平尚不足以产生严重的地表水酸化问题,周边国家不应过分夸大我国排放酸性气体的越境输送导致的环境影响.

In order to evaluate the status of surface water acidification in Northeast China,chemical composition of 33 small streams was investigated in August,2011.It was found that only a few waters located in Changbai Mountain had pH of lower than 6.0,and all waters had acid neutralizing capacity（ANC） of higher than 0.2 meq·L-1.This indicated that surface water acidification was not a regional environmental issue in Northeast China.HCO-3 was the major anion,with SO2-4 concentration mostly below 150 μeq·L-1 and even much lower NO-3 concentration.Low concentration of SO2-4 and NO-3 means no serious acid deposition in this area.However,the distribution of acidic forest soils,with low base cation weathering rate,could only provide limited buffering capacity for surface water to acidification in Northeast China,and the potential risk of water acidification still existed.Currently,acid deposition in Northeast Asia could hardly cause severe acidification of surface water.The neighboring countries should therefore not amplify the environmental impact by transboundary air pollutants from China.