水溶性有机物和非离子表面活性剂对土壤中芘生态毒性的影响

Effects of dissolved organic matter and nonionic surfactants on the ecotoxicity of pyrene in the soil

采用生物培养和物理化学试验研究了水溶性有机物(DOM)和非离子表面活性剂对土壤中芘生态毒性的影响。结果表明,水溶性有机物具有表面活性。水稻根的芘毒害敏感区间为0～200 mg/kg,100mg/kg是土壤中芘对水稻根伸长最大抑制率质量比。DOM的存在会降低芘的生态毒性,且芘生态毒性的降低程度随DOM质量浓度的增大而增大。在试验条件下,DOM和表面活性剂单一作用对芘生态毒性均有减轻的趋势;当DOM和表面活性剂共存时,芘的生态毒性则比DOM单独作用时的结果弱,而强于表面活性剂单独作用的结果。

The present paper is concerned about our study findings of the effects of dissolved organic matter（DOM） and nonionie surfactants on ecotoxicity of pyrene in the soil. The results of our experiments show that DOM is a kind of surfaetant. With the increase of its concentration, the surface tension of DOM solution would decrease more tardily by 14.9 mN/m in the range of test concentration. However, the surface tension of surfaetant Tween - 80 and Triton X - 100 tends to decrease at the test concentration range on a big margin by 24.7 mN/m and 22.6 mN/m, respectively. The sensitive range of pyrene inhibiting root elongation of Oryza sativa stands from 0 to 200 mg/kg, while its maximal inhibition concentration is 100 mg/kg. At the presence of DOM, it would be possible for the eco-toxicity of pyrene to get alleviated with the inhabited degree related to surface activity. Such effects could he strengthened with increase of the concentration of DOM. In our experiment, we managed to alleviate the eeo-toxieity of pyrene of Oryza sativa by adding DOM to the pyrene-contaminated soil, for example, by adding Tween - 80 and Triton R X - 100 to it. Joining DOM, and the surfactant Triton and Tween, the inhibition rate of pyrene root elongation is likely to get significantly reduced with increase of concentration of DOM and the surfaetants, on the contrary, the seed germination index could be found increased with the rising concentration The results also indicated that, when DOM added to soil together with Tween - 80 or TritonR X - 100, the eco-toxicity of pyrene of Oryza sativa was weaker than that effected by adding DOM to soil singly, and strengthener than that effeeted by adding Tween - 80 or TritonR X - 100 singly. Comparing the DOM treatment individually, it would be possible to reduce the inhibitory effect of pyrene significantly on the root elongation of Oryza sativa, but the trend still turns to be declining with the increase of DOM mass fraction. To be sure, its inhibition rate is likely to drop by 8.26% to 15.47% （Tween-80） and 4.93%to 11.20% （Triton X-100） in the test concentration.