模拟酸雨对灰潮土中铅、镉的浸出特性研究

为了研究酸雨作用下灰潮土铅、镉的释放规律。通过对采自田河村(S1)及河口大桥(S2)灰潮土样品进行模拟酸雨淋溶试验,研究了湖北省孝感地区灰潮土中铅、镉的浸出特性。720 ml的模拟酸雨淋洗后,pH值4.5的模拟酸雨使供试灰潮土镉累积浸出比正常降水增加19.5%(S1)和60.9%(S2),使铅的浸出增加87.7%(S1)和12.9%(S2);pH值3.5的模拟酸雨使灰潮土镉累积浸出比正常降水增加45.6%(S1)和80.3%(S2),使铅的浸出增加183.7%(S1)和424.7%(S2);土样S2的总镉和总铅的含量都要比S1土样高,pH值3.5下呈现出镉和铅累积浸出量也较大。镉的浸出随着淋洗液pH值降低淋出量逐渐增加,铅的浸出则在pH值3.5时出现显著增加。镉与铅都随着酸度增加和淋溶量的增加而逐渐浸出。

Effect of the Simulative Acid Rain on the Leaching Characteristics of Pb and Cd in Calcareous Alluvial Soil

The releasing law of Pb and Cd in calcareous alluvial soil under the action of acid rain was studied.Through simulative acid rain leaching experiment in calcareous alluvial soil samples from Tianhe village(S1) and estuarine bridge(S2),the leaching characteristic of Pb and Cd in calcareous alluvial soil in Xiaogan district of Hubei province was studied.Compared with the normal rainfall,after leached by simulative acid rainfall of 720 ml,simulative acid rain with pH 4.5 enhanced the cumulative leaching amount of Cd 19.5%(S1) and 60.9%(S2),Pb 87.7%(S1) and 12.9%(S2) in calcareous alluvial soil;simulative acid rain with pH 3.5 enhanced the cumulative leaching amount of Cd 45.6%(S1) and 80.3%(S2),Pb 183.7%(S1) and 424.7%(S2) in calcareous alluvial soil.Total Cd content and total Pb content were higher in soil sample S2 than that in soil sample S1,and the cumulative leaching amount was quite large at pH 3.5.The cumulative leaching amount of Cd increased gradually along with reducing pH value of rainfall and that of Pb increased significantly at pH 3.5.Cd and Pb were gradually leached along with the acidity and leaching amount increasing.