森林对污染物湿沉降过滤作用的研究

研究了四川乐山市沙湾区德胜钢铁公司附近的马尾松林、香樟林这两种森林生态系统的大气降水、穿透雨和树干径流以及土壤渗透水的污染物离子浓度并和裸地相对比,以期了解这3种生态系统对酸沉降的过滤作用。研究结果如下:①大气降水的SO42-、NO3-、Cl-和F-浓度分别为30.36 mg/L,3.56 mg/L,1.41 mg/L,0.75 mg/L,表明SO2是该区的最主要酸性污染物质。②马尾松、香樟林群落的穿透雨和树干径流中污染物质含量显著高于大气降水,表明森林对大气污染物具有显著的截留作用。马尾松林的穿透雨和树干径流的污染物离子的总量高于香樟林,表明马尾松林对酸性污染物质的截留作用高于香樟林。③两种林型的土壤渗滤水的污染物质含量比起树干径流有比较明显下降,这表明土壤对酸性污染物具有明显的截持和吸附作用。④对输入和输出不同生态系统的污染物各离子含量比较,并与裸地相对照发现,森林生态系统均对污染物起到了明显的拦截和积蓄作用。综上,森林生态系统对酸沉降具有明显的过滤作用。

Study on the function of forest in filtering wet deposition of pollutants

This paper examines the ionic concentrations of pollutants in the precipitation,throughfall,stem flow and underflow of two forest ecosystems in Shawan of Sichuan in contrast to bare field.The results indicate that:(1) the concentrations of SO_4~(2-),NO~-_3,Cl~-and F~-were 30.36?mg/L,3.56?mg/L,1.41?mg/L,and 0.75?mg/L respectively,suggesting a higher contribution of SO_2 to acid deposition;(2) the ionic concentrations of the throughfall and stem flows of forest communities are significantly higher than those in the precipitation;(3) in both types of forests,the pollutant concentrations in the underflows are significantly lower than those in stem flows;(4) by comparing the input and output system of the ionic concentrations of pollutants,we found that the forests play a significant role in intercepting and accumulating wet deposition of air pollutants.These observations support the supposition that "forests are filters of acid deposition pollutants".