Abstract:

This study was conducted in the Huoditang naturally-regenerated forest, which is located at the center of the natural forest region across the southern-slope of the Qinling Mountains. Rainwater and stream water samples were collected mainly in rainy seasons in the area. The sample pH values and chemical concentrations were measured. The response of stream water chemistry to rainwater acidification in the region was studied. The results showed that long time rainwater acidification could result in reduction of pH value, Ca²⁺ and Mg²⁺ concentration in the strean water. The changes of K⁺, Na⁺ concentration of stream water were not correlated with the rainwater acidification. There was no response of Zn, Pb and Cd concentration of the stream water to rainwater acidification. The acidified rainwater did not result in the release of the heavy metals enriched in the forest soil.

Key words: Qinling Mountains, forest, water chemistry, rainwater acidification