四川盆地地表水酸化现状与趋势
摘要
A regional survey of surface water acidification in Sichuan Basin was carried out during 2009–2011. Analysis of more than 90 samples revealed high pH and acid neutralizing capacity (ANC) in most surface waters, indicating that surface water acidification might not be a serious environmental issue in Sichuan Basin. However, some acidified surface water systems were present. Comparison of the results with a survey conducted 20 years ago revealed a significant decrease in ANC and increasing sulfate (SO42 ) and nitrate (NO3) concentrations. Rapid increases in sulfur dioxide (SO2 ) and nitrogen oxides (NOx ) emissions were likely the primary cause of surface water acidification, while high weathering of the purple soil in Sichuan Basin likely enabled strong buffering against acidification of surface water. However, low weathering occurred in areas of yellow earth and yellow-brown earth in the surrounding mountains, indicating that serious acid deposition could lead to acidification of surface water in these areas.