【摘要】 老化是指有机污染物进入土壤后,随着时间的增加,其生物有效性、毒性和可浸提性会逐渐下降的现象.采用室内培养法研究了外加多环芳烃芘在2种水稻土乌栅土(潜育型水稻土)和黄泥土(潴育型水稻土)及其不同粒组团聚体中的老化现象,并采用二氯甲烷提取和蚯蚓吸收试验比较了培养老化后外加多环芳烃芘的可浸提性和生物有效性的变化.结果表明,培养90d后芘的浸提率下降了15%~23%,蚯蚓的摄食量也下降了37%~67%,说明外加有机污染物进入水稻土后发生了显著的老化现象,从而降低了其环境移动性和生物有效性.但不同粒径团聚体中老化程度没有差异,不过对蚯蚓的生物有效性存在差异.因此,并不能根据土壤中有机污染物的含量来预测其环境风险和生物有效性.更多还原

【Abstract】 Effect of aging on bioavailability and extractability of persistent organic pollutants has recently been paid much attention in environmental studies. This study deals with aging of spiked pyrene,a four-ring polycyclic hydrocarbon,in two paddy soils and their particle-size fractions under laboratory incubation and change in its extractability and bioavailability.The bioavailability of aged pyrene was tested by an assay of exposure to earthworms(Eisenia foetida).The extractability of spiked pyrene was decreased by 15% to 23%,and the bioavailability to earthworm was decreased by 37% to 67% after incubation for 90 d compared to under no incubation.Meanwhile,there was no significant difference in the pyrene extractability between incubation with different size fractions of a single soil.Soil incubation resulted in lower extractability and,thus,lower environmental risk of the organic pollutants after incorporation in paddy soils and their aggregates.The different size fractions of paddy soils may exert different bioavailability when exposure to soil fauna.Thus,content and chemical extractability may not be appropriate index for assessing the potential environmental risk and bioavailability to soil fauna for persistent organic pollutants in paddy soils.更多还原