长期灌溉含多环芳烃污水对稻田土壤酶活性与微生物种群数量的影响

Effects of long-term PAHs-containing wastewater irrigation on lowland rice soil enzyme activities and microbial populations

以沈抚污水灌区为例,研究了长期灌溉含多环芳烃(PAHs)污水对稻田土壤酶活性、微生物种群数量的影响。结果表明,灌区稻田土壤PAHs含量在319.5～6362.8μg.kg-1。长期污水灌溉导致稻田土壤PAHs含量严重超过环境标准。随清水连续灌溉年限的增加,土壤PAHs总量不同程度降低直至低于土壤PAHs环境质量标准。相关性分析表明,在目前污染程度下,灌区稻田3大土壤微生物类群和主要功能群的种群数量主要受土壤理化性质的影响,受PAHs含量影响不明显。土壤全氮含量与细菌数量呈极显著正相关(P<0.01)。土壤酶活性受到土壤养分和PAHs污染的双重影响,土壤有机碳和全磷含量分别与脱氢酶、多酚氧化酶和脲酶活性呈极显著正相关(P<0.01),PAHs含量分别与脱氢酶和脲酶活性呈极显著正相关(P<0.01),与多酚氧化酶活性呈显著正相关(P<0.05)。

A case study was conducted in the Shenfu irrigation area to investigate the eUects ot long-term PAHs-containing wastewater irrigation on the activities of dehydrogenase, polyphenol oxidase and urease and on the microbial populations in lowland rice soil. The results showed that after a long-term PAHs-containing wastewater irrigation, the PAHs content in test soil ranged from 319.5 to 6 362.8 μg.kg-^1, which surpassed the environmental standard seriously. With the increasing year of freshwater irrigation, soil PAHs content decreased to different degrees, up to the level below environmental standard. Correlation analysis indicated that the quantities of soil microbial and main functional populations were mainly affected by soil physical and chemical properties, and less affected by soil PAHs content. The numbers of soil bacteria had very significantly positive correlations with soil total N, positively correlated with the contents of soil while the test enzyme activities were significantly organic C, total P and PAHs.