中文摘要：

Benzo（a）pyrene （B[a]P）作为典型具有＂三致＂效应的持久性有机污染物,在土壤中逐步累积,对土壤生态安全造成潜在威胁.通过一次与多次污染的方法,研究B[a]P在土壤中的有效性特征及其对蚯蚓（Eisenia fetida）体腔细胞染色体畸变及溶酶体膜完整性的毒性效应.结果显示：随着培养时间的延长,土壤中B[a]P含量及蚯蚓体内B[a]P富集量、蚯蚓体腔细胞微核变率均呈现初期（28 d）下降速率较快,尔后（28-56 d）下降速率减小的趋势;而蚯蚓体腔细胞中性红保留时间（NRRT）升高速率呈先快后慢的趋势.土壤中B[a]P的Tenax法提取含量与蚯蚓体内B[a]P富集量呈极显著正相关（R2=8614,P〈0.01）;蚯蚓体腔细胞NRRT和微核变率分别与土壤中B[a]P的Tenax法提取含量和蚯蚓体内B[a]P富集量呈显著正相关（P〈0.05）.相同培养时间内,多次叠加污染土壤中B[a]P的Tenax提取含量和蚯蚓富集量显著低于一次污染26.00%（P〈0.05）;蚯蚓体腔细胞NRRT平均比一次污染高13.00%（P〈0.05）;体腔细胞微核率比一次污染低36.10%（P〈0.05）.本研究表明土壤B[a]P多次叠加污染对蚯蚓的毒性效应低于一次污染,结果可为土壤PAHs类污染物的生态毒性效应评价提供理论基础.

英文摘要：

In order to understand Benzo（a）pyrene （B[a]P） bioavailability in soil and its accumulation in earthworms, it is necessary to study B[a]P fate in soil and its toxic effect on earthworms. This study investigated the effects of multiple and one-time addition of B[a]P in soil on its availability and the neutral red retention time （NRRT） as well as the micronucleus rates in earthworm coelomocytes. By using multiple and one-time addition methods, exposure experiments with different aging times of B[a]P （1, 7, 14, 28, and 56 days） were conducted to analyze the contents of B[a]P in soil by chemical solvent （accelerated solvent extraction, ASE） and Tenax-TA extractive methods. Earthworms were exposed to soils with different aging time of B[a]P. After exposure for 7 days, earthworms were collected for analysis of B[a]P enriched, neural red retention time and micronucleus rates in coelomocytes. The contents of ASE and Tenax extractable B[a]P in soil and the amounts of B[a]P enriched in earthworms sharply declined in the first 28 d （0-28 d）, and then slowly decreased between 28 d and 56 d for both the multiple and one-time addition methods. The micronucleus rates in earthworms sharply declined, while the NRRT in earthworm coelomocytes greatly increased in the first stage, and then slowly decreased in the following incubation time for both addition methods. The results showed a very significantly positive correlation （R2 = 0.8614, P 〈 0.01） between the amounts of B[a]P accumulated in earthworms and the contents of B[a]P extracted from soil by Tenax. The available contents of B[a] P in soil and the amounts of B[a]P enriched in earthworms in multiple addition were 26.00% and 36.04% lower than that in the one-time pollution treatment. The NRRT and mieronucleus rate in earthworm coelomoeytes in the multiple addition was 13.00% higher and 36.10% lower than those in the one-time addition, respectively. To sum up, this study provides important data for assessing ecological toxicity of multiple addition