辽河流域土壤酸化与作物籽实镉生物效应的地球化学预警

摘要

土壤酸化及其引发的生态安全问题是公众广泛关注、全球研究的热点.辽河流域多目标区域地球化学调查结果显示:当土壤中的w (CaO+K2O)≥3.86％时,土壤对酸性沉降物具有缓冲能力；当w(CaO+K2O)＜3.86％时,则土壤对酸性沉降物的缓冲能力显著下降.利用土壤酸化缓冲能力的地球化学预测模型,对全流域土壤酸化的缓冲能力进行了预测,指出辽河流域东部,即营口—鞍山—辽阳—沈阳—抚顺—铁岭—开源的广大区域内既是土壤酸化的脆弱区,也是作物籽实Cd超标的预警区,辽河流域土壤酸化区域将进一步扩大.%The impact of acidified soil and the subsequent effects on terrestrial ecosystems has raised public concern and become a hot research topic over the past decade. From 2002 to 2004, a systematic soil geochemical survey was conducted with the aim of studying the changing trend of the soil chemical elements in the catchment area of Liaohe in Liaoning Province. The results showed that the pH is unaffected by acid inputs when CaO+K2O concentration in soil is more than 3. 86%, which may buffer against the acidity inputs, whereas the soil pH drops rapidly when CaO + K2O concentration in soil is lower than 3. 86%. A map of buffering ability was developed, and it predicted that the soil in the eastern region of Liaohe catchment is much more vulnerable to further acidification. We then discuss the effects of increased Cd leaching upon soil acidic processes, biogeoehemieal processes, areas susceptible to Cd in rice and maize seeds are manifested.