采用土壤多次叠加污染与一次污染的方法研究B[a]P对赤子爱胜蚓组织细胞谷胱甘肽-S-转移酶（GST）的毒性效应。结果表明，随着土壤中B[a]P培养时间的延长，土壤中B[a]P含量和蚯蚓组织细胞GST活力呈现初期下降速率较快，尔后下降速率减小的趋势；蚯蚓组织细胞GST活力与蚯蚓体内B[a]P富集量之间呈极显著正相关(P＜0.01)。在整个培养时间内(1~56 d)，多次累积污染土壤中B[a]P的Tenax提取含量和蚯蚓体内B[a]P富集总量比一次污染显著降低13.34%~27.98% ( P＜0.05)与22.58%～46.81%( P＜0.05)。B[a]P多次累积污染条件下蚯蚓组织细胞GST活力比一次污染低3.01%~33.07%(P＜0.05)。这表明土壤中B[a]P多次累积污染对蚯蚓的毒性低于一次污染。研究结果为蚯蚓在土壤B[a]P叠加污染条件下的生态毒性效应评价提供理论依据。
Benzo(a)pyrene (B[a]P), one of the most persistent organic pollutants, is gradually accumulating in the soil and becoming a serious threat to soil environment. However, the long-term toxic effects of B[a]P on soil organisms including earthworms remains unknown. Responses of earthworms to the one-time or multiple-time superimposed B[a]P pollution are still unclear. Using multiple-time superimposed and one-time pollution methods, the effect of B[a]P on glutathione-S-transferease(GST) activity in earthworms was investigated. Results showed that the content of the available B[a]P in the soil and the B[a]P quantity in earthworms sharply declined in the first 28 d (0-28 d) and then slowly decreased between 28 and 56 d in both the multiple-time and one-time addition methods. The GST activity in earthworms sharply declined in the first stage (1-28 d) and then slowly decreased between 28 and 56 d in both addition methods. A significantly positive correlation (p<0.01) between the quantity of B[a]P accumulated and the GST activity in earthworms was detected. Moreover, the available B[a]P in soil and the B[a]P accumulated in earthworms in multiple-time addition treatment were ranged from 13.34% to 27.98% and from 22.58% to 46.81%, respectively, which was lower than those in the one-time pollution treatment. The activity of GST in earthworm’s tissue cells under multiple-time superimposed pollution was 3.01% to 33.07% lower than that in one-time pollution treatment during the whole incubation time. This results indicated that the soil available B[a]P and it’s toxicity to earthworms in the multiple-time polluted soil was lower than that in the one-time polluted soil.