扑草净对鲫鱼(Carassius auratus)生长的影响及其导致的水体营养盐变化

Laboratory experiments on the effect of prometryn on the growth process of crucian carp(Carassius auratus)and the variation of nutrient concentrations

为评价扑草净在水环境中造成的生态风险,以扑草净作为目标污染物,以鲫鱼作为受试生物,于实验室内水族箱中进行试验。持续监测鲫鱼体质量体长及水体营养盐浓度,考察扑草净对鲫鱼生长的影响,及其导致的水体营养盐浓度变化特征。结果表明:鲫鱼体质量生长率、体长生长率及营养盐浓度随时间的变化可利用Logistic方程描述(R^2=0.959~0.997);有扑草净组鲫鱼体质量生长率等比无扑草净组低8.7%~50.3%。无鱼时扑草净对水体中氮磷营养盐浓度、营养盐比例及总氮/总磷比例无显著影响;有鱼时,有扑草净组的总颗粒氮和总颗粒磷浓度分别比无扑草净组低41.4%及33.8%,有无扑草净组各形态磷营养盐浓度与总磷的比例以及总氮/总磷浓度比例差异显著。研究表明扑草净对鲫鱼的毒性效应可间接影响水体营养盐浓度。

In order to evaluate the ecological risk of prometryn in the water environment,prometryn and crucian carp(Carassius auratus)were chosen respectively as the target pollutant and target organism to investigate the effect of prometryn on the growth of crucian carp and the variations of nutrient concentrations in the water.To this end,the weight and length of crucian carp raised in the aquariums in the laboratory and the concentrations of nutrients in the water were continuously monitored.The results showed that variations of fish weight gain rates,length gain rates,and nutrient concentrations with time could be described well with Logistic equation(R^2=0.959-0.997),and the weight gain rate and protein efficiency ratio of fish in groups with prometryn was 8.7%-50.3%(P<0.05)lower than those in groups without prometryn.In fishless groups,no significant effect of prometryn on nutrient concentrations and ratios of TN/TP concentration was observed;whereas when there was fish in the aquariums,TPN and TPP concentrations with prometryn were 41.4%and 33.8%(P<0.05)lower than those without prometryn respectively.In addition,prometryn also had a significant effect on the proportion of various nutrients and total TN concentration/total TP concentration(P<0.05).It was shown that the toxic effect of prometryn on crucian carp could indirectly affect the concentrations of nutrients in the water.