摘要
腐植酸(HA)是水环境中一类重要的溶解性有机质,它能影响有机污染物对生物的急性毒性。以除草剂扑草净(Prometryn)作为目标污染物,模式生物斑马鱼(Danio rerio)作为受试生物,研究了扑草净对斑马鱼的96 h急性毒性以及HA存在下其对斑马鱼的毒性变化情况。结果显示,扑草净对斑马鱼的96 h半致死浓度(96 h LC50)为7.448 mg·L-1,95%置信区间为(7.032~7.971)mg·L-1。5 mg·L-1的HA对扑草净的毒性没有显著影响,但当扑草净浓度为8.5 mg·L-1时,15 mg·L-1的HA增加了其对斑马鱼的96 h累积死亡率,较同样扑草净浓度下无HA组高出40%。研究表明在较高扑草净浓度下,15 mg·L-1HA能增加其对斑马鱼的急性毒性,这可能是由于较高浓度(大于LC50值)的扑草净与HA共存时,减少污染物毒性的络合机制被其他能够引起毒性增加的机制所掩盖。
Humic acid(HA) is a principal component of dissolved organic matters in all aquatic ecosystems. It comprises of a variety of molecular structures and functional groups and can bind pollutants in the water, thereby affecting the pollutant toxicity to aquatic organisms.In this study, a triazine herbicide prometryn, commonly present in the surface and ground water, was chosen as the target pollutant and a model organism zebrafish(Danio rerio) as the target organism. The aim of this study was to investigate the acute toxicity of prometryn to Danio rerio at 5 and 15 mg·L-1HA concentrations. Under single prometryn exposure, the 24 h, 48 h, 72 h, and 96 h median lethal concentrations(LC50)of prometryn to Danio rerio were 9.143, 8.432, 7.645, and 7.448 mg·L-1and 95% confidence intervals were 8.635~9.861,7.408~9.934, 7.041~8.310, and 7.032~7.971 mg·L-1, respectively. Based on these acute toxic experiment results, prometryn had the high toxicity to Danio rerio. In addition, 96 h cumulative mortality rate of Danio rerio did not change obviously with 5 mg·L-1HA when the concentrations of prometryn were 6.5, 7.5, and 8.5 mg·L-1. In contrast, the same toxicological parameter became 40% higher at 15 mg·L-1HA than HA-free when prometryn concentration was 8.5 mg·L-1. It was shown that HA can increase the acute toxicity under higher prometryn concentrations. This might be explained by a hypothesis that the association of prometryn with DOM reducing its toxicity might be overshadowed by other mechanisms actually enhancing its toxicity in water.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2015年第4期653-659,共7页
Journal of Agro-Environment Science
基金
国家水体污染控制与治理科技重大专项(2012ZX07501-003)
关键词
腐植酸
扑草净
急性毒性
斑马鱼
humic acid(HA)
prometryn
acute toxoticy
zebrafish(Danio rerio)
