城镇污水处理厂进出水对日本青鱂早期阶段亚慢性毒性效应

采用日本青鳉胚胎及幼鱼暴露评估污水处理厂进出水的综合毒性效应。水样采自广州市3个污水处理厂的进水口和出水口。96 h青鳉幼鱼急性毒性试验表明:6个水样均没有对青鳉幼鱼产生急性毒性效应。14 d胚胎暴露试验结果:3个污水处理厂的进水及1号和3号污水处理厂的出水均引起胚胎死亡,胚胎孵化率均低于70%且均与对照组产生了显著性差异(p0.05)。3个厂的进水和1号、2号厂出水的鱼苗畸形率与对照组也有显著差异(p0.05),其中3号厂进水鱼苗畸形率高达(33.73±8.94)%。而6个水样的胚胎孵化时间均与对照组无显著差异(p0.05),均在9 d左右。7 d鱼苗暴露试验结果:1、2、3号3个水厂进水的鱼苗死亡率分别是(30.16±2.75)%,(24.07±1.60)%,(37.90±4.77)%,与对照组产生明显差异(p0.05)。出水对鱼苗的致死效应明显低于进水,但出水对鱼苗的致死效应相对于对照组仍有显著差异(p0.05)。

Subchronic Toxicity Effect of the Wastewater and Effluent from Municipal Sewage Treatment Plants on Early Life Stage Japanese Medaka (Oryzias latipes)

The comprehensive toxicity effect of the wastewater and effluent from three sewage treatment plants was evaluated making use of the embryo and fry of Japanese medaka (Oryzias latipes). Three sewage treatment plants included two plants dealing with the sewage from domestic sewage (No. 1 and 2), while the rest sewage mainly dealt with the dyeing wastewater in Guangzhou. The results of 96-h acute toxicity test showed that six water samples had no acute toxicity effect to juvenile fish. The results of 14-d embryonic exposure test showed that the wastewater of three sewage treatment plants and the effluent of No.1 and 3 plants caused death of embryos, and the embryo incubation rates were all less than 70% and had significant difference with control groups(p<0.05). Fry's deformity rate of all wastewater and effluent of No.1 and 2 plants also had significant difference with control groups (p<0.05), including fry's deformity rate of the wastewater of No. 3 reaches as high as (33.73±8.94)%. But there was no obvious difference in embryo incubation time of six water samples with control groups (p>0.05), all about 9 d. The results of fish fry's 7-d exposure test showed that fish fry's mortality of the wastewater of No. 1, 2, 3 plants respectively were (30.16±2.75)%, (24.07±1.60)%, (37.90±4.77)%, and had significant difference with control groups (p<0.05). The lethal effect of the effluent to fish fry were significantly lower than the wastewater, however the lethal effect of the effluent to fry still had obvious difference compared with control groups (p<0.05).