封闭群稀有鮈鲫对几种常见化学品的敏感性

采用96h急性毒性试验检测了稀有鮈鲫封闭群和野生群对重铬酸钾、五氯酚、氯化汞、对氯苯胺、氯化镉等几种常见化学品的敏感性差异,并通过7d亚慢性毒性试验以及胚胎-卵黄囊吸收阶段毒性试验检测了对氯苯胺、氯化镉对稀有鮈鲫封闭群的亚慢性毒性.急性毒性试验结果表明,Cr6+、五氯酚、Hg2+、对氯苯胺和Cd2+对稀有鮈鲫封闭群的96h LC50分别为69.0mg/L,111.4,56.9μg/L,35.5,12.2mg/L;Cr6+对封闭群的96h LC50低于野生群(99.8mg/L)(P0.05).胚胎-卵黄囊吸收阶段和7d亚慢性毒性测试结果表明,Cd2+和对氯苯胺暴露后封闭群在孵化率、畸形率、死亡率、生长等方面均表现出毒性效应,其中生长指标更为敏感.以生长为观测指标,2种试验的结果无显著差异,对Cd2+的NOEC均为0.1mg/L,胚胎-卵黄囊吸收阶段试验中对氯苯胺的NOEC为2mg/L,7d亚慢性毒性试验中对氯苯胺的NOEC为4mg/L.本研究证明了稀有鮈鲫封闭群对化学药品的敏感性高,可作为化学品生态毒理学测试的种源.

Sensitivity of rare minnow (Gobiocypris rarus,IHB) to several common chemicals

We performed waterborne exposures of several chemicals on adult and embryo-larvae stage rare minnow and compared the sensitivity between the wild group (WG) and closed colony (IHB). Adult rare minnows were acutely exposed to lethal concentrations of the chemical agents (K2Cr2O4, pentachlorophenol, HgCl2, p-Chloroaniline and CdCl2) in order to determine the 96 h LC50 (96 h lethal median concentration). For the closed colony, the 96h LC50was 69.0mg/L, 111.4, 56.9 μg/L, 35.5and12.2mg/L for Cr6+, pentachlorophenol, Hg2+, p-Chloroaniline and Cd2+, respectively. For the wild colony, the 96h LC50was 99.8mg/L, 105.6and 65.8 μg/L for Cr6+, pentachlorophenol, Hg2+, respectively. A significant difference was observed in the exposure to K2Cr2O4between the two colonies (P<0.05). Then the embryos (8hours post-fertilization) and larvae (1day post-hatching) from closed colony were exposed to p-Chloroaniline and CdCl2for 7days and the exposure caused toxic effects on hatching, malformation, survival and growth, and among these, growth was the most sensitive parameter to the toxicants stress. For p-Chloroaniline, the obtained none-observable effect concentration (NOEC) for growth were 2and 4mg/L in the embryos and larvae, respectively; while for CdCl2, the NOEC was 0.1mg/L in both the embryos and larvae. Our results suggested that the closed colony rare minnow is sensitive to chemical exposure and can serve as a reliable model organism for testing chemical toxicity.