微塑料对大型溞的急性毒性研究

为了解微塑料对淡水生态环境的影响, 选择了大型溞作为受试生物, 研究了聚氯乙烯(PVC)对其产生的急性毒性效应与恢复试验。研究设置了7个 PVC浓度梯度, 范围是0—400 mg/L, 等比系数为2, 对其进行急性毒性处理, 测定96h LC₅₀, 并对大型溞心率变化和抗氧化指标进行测定。同时, 对其进行清水21d恢复实验。96h LC₅₀为130.132 mg/L, 95%置信区间为82.864—234.989 mg/L。处理组与对照组相比, 高浓度组心率具有显著性差异(P<0.05), 低浓度组无显著性差异(P>0.05); 高浓度组摄食率具有极显著差异(P<0.01), 低浓度组无显著性差异(P>0.05); 高浓度组SOD、GSH值具有显著性差异(P<0.05), 低浓度组并不显著(P>0.05)。处理组与对照组相比, 处理组的生育力明显提高, 首次产幼时间提前, 但后代体长变短, 出现畸形个体; 处理组的后代死亡数高于对照组, 母溞体长缩短, 但并不显著。结果表明, PVC的暴露对大型溞具有一定的毒性效应, 短期暴露会对其后续生长和繁殖产生不利影响。

STUDY ON ACUTE TOXICITY OF MICROPLASTIC TO DAPHNIA MAGNA

In order to understand the impact of microplastics on the ecological environment of freshwater,we choose Daphnia magna as test organisms and studied the acute toxicity of PVC and recovery test of PVC.Seven groups of PVC concentration gradient and four repetition groups were set up.The range was 0—400 mg/L and the equivalence coefficient was 2.After 96h acute toxic exposure,the LC₅₀,heart rate and antioxidant index were determined.The recovery experiment without PVC for 21 days was also conducted.The 96-hour LC₅₀ was 130.132 mg/L,and the 95% confidence interval from 82.864 to 234.989 mg/L.Compared with the control group,the heart rate of the high concentration groups(50—200 mg/L)were significantly different(P<0.05),while the low concentration group had no significant difference(P>0.05);the ingestion rate of the high concentration groups(25—200 mg/L)had a significant difference(P<0.01),and the low concentration group had no significant difference(P>0.05);the SOD and GSH values of the high concentration group(200 mg/L)had significant differences(P<0.05),but the low concentration group had no significant difference(P>0.05).The first reproduction time was advanced,but the body length of the offspring became shorter and deformed.The number of deaths in the offspring of the treatment group was higher than that of the control group.The body length of the female was shortened than the control group.These results showed that D.magna exposed to PVC caused itself toxic injury,and short-term exposure would lead to adverse effects on the growth and reproduction of D.magna.