模拟酸雨对太湖地区水稻土铜吸附—解吸的影响

EFFECT OF SIMULATED ACID RAIN ON ADSORPTION AND DESORPTION OF COPPER BY PADDY SOILS IN TAIHU LAKE REGION

以太湖地区三种典型的水稻土 (黄泥土、白土、乌泥土 )为例 ,利用模拟—培养试验 ,着重研究模拟酸雨对土壤的铜吸附解吸能力的影响。研究结果表明 :与未淋溶土壤相比 ,经模拟酸雨淋溶的三种土壤对铜的吸附量有所增加 ,随着淋溶液 pH的降低 ,增幅减小 :易解吸态铜的解吸量则随淋溶液 pH的降低而增大 ,模拟酸雨降低了土壤对重金属污染的缓冲能力 ;虽然黄泥土、乌泥土对铜的吸附量远大于白土 。

Three typical paddy soils, hydragric paddy soil, bleached paddy soil and gleyed paddy soil, collected from the Taihu Lake region were used to investigate effect of acid rain on adsorption and desorption of copper by soils by using simulatio n and incubation approaches. Results indicated that when soils were leached with simulated acid rain, copper adsorption capacity of all three soils increased as compared to that of the un-leached control soils. Lower pH of leaching solution tended to bring about smaller increment in adsorption capacity. The amount of Cu released from the fraction of the KNO 3-extractable Cu was increased with the decrease in pH of the leaching solution, suggesting that soils suffering from ac id rain leaching decreased their capability to buffer the heavy metals pollution . Soils with large adsorption capacity such as hydragric paddy soil and gleyed p addy soil were more heavily affected by simulated acid rain than the soils with small adsorption capacity ( e.g. bleached paddy soil).