蚯蚓生物积累表征土壤中芘的生物有效性研究

Prediction of Pyrene Bioavailability in Soil by Earthworm (Eisenia Foetida) Bioaccumulation

利用蚯蚓作为测试生物,引入蚯蚓-土壤积累因子(Earthworm-SoilAccumulationFactor,ESAF),就不同土壤中芘对蚯蚓的生物有效性进行了考察和研究。试验结果表明,蚯蚓在土壤中培养10d,体内积累芘的浓度达到平衡,积累浓度与土壤初始染毒浓度成显著正相关;土壤性质对土壤中芘的生物有效性具有非常重要的影响,土壤有机质、粘土矿含量越高,对芘的吸持能力越强,ESAF越小。

Earthworms (Eisenia Foetida) were used as test organisms in this study to reveal bioavailability of pyrene in soil. Earthworm- soil accumulation factor (ESAF) was introduced to express the bioavailability of pyrene in different soils to the earthworms. ESAF was expressed as accumulated concentration of pyrene in the earthworm at steady- state divided by its concentration in the soil. Bioaccumulation dynamic suggested that pyrene concentration in the earthworm tissues reached bioaccumulation steady- state as earthworm was incubated in a period of 10 days. The accumulated concentration of pyrene in the earthworm tissues reached to 0.42～ 71.50 mg· kg- 1. FW and was positively proportional to the initial concentrations of pyrene in the studied soils (R2, 0.888～ 0.996). The calculated ESAF was 0.052～ 0.451. ESAF was negatively proportional to organic matter content in the studied soils (R2, 0.982). For 1# soil with 186.8 g· kg- 1 of organic matter, the percentage of pyrene accumulated in earthworm tissues was only in a range of 1.27% ～ 2.52% , whereas the accumulation percentage in worm tissues was in 14.30% ～ 22.70% for 5# soil with 6.0 g· kg- 1 of organic matter. For the rest soils, the percentages of pyrene accumulated were in athe range of that between 1# and 5# . It should be noticed that, although the 3 g· kg- 1 of organic matter in 6# clay sample was lower than 6 g· kg- 1 in 5# sandy loam, the percentage of accumulated from 6# was lower than that of 5# which indicated that besides to the organic matter content, clay may exert great effect on the behavior of the organic pollutants. On the whole, the results suggested that the capacity for preserving pyrene increased as the organic matter and clay contents in soil increased, and hence the value of ESAF decreased.