三峡库区水样中重金属含量及其对斑马鱼胚胎发育的毒性评价  

ANALYSIS OF HEAVY METALS IN THE SURFACE WATER FROM THE THREE GORGES RESERVOIR AND ITS TOXIC EFFECTS ON THE EMBRYONIC DEVELOPMENT OF THE ZEBRAFISH

作　　者：郭勇勇[1] 华江环[1] 杨丽华[1] 周炳升[1] 

机构地区：[1]中国科学院水生生物研究所淡水生态与生物技术国家重点实验室,武汉430072

出　　处：《水生生物学报》2015年第5期885-892,共8页Acta Hydrobiologica Sinica

基　　金：中国长江三峡集团公司科研项目(CT-12-08-01)资助

摘　　要：三峡库区水体污染对库区鱼类生存的影响尚不明晰,因此测试库区水体中污染物含量及其对鱼类早期发育的影响对于库区生态渔业的安全发展具重要意义。研究于三峡库区坝前段典型区域设置3个采样点,用ICP-MS分析了原水中13种重金属的含量,并将斑马鱼胚胎暴露于纤维膜过滤后的水样中,测试其内分泌及发育毒性效应。结果表明,三峡库区水样中13种重金属的浓度均低于地表水环境标准规定的限值,且3号采样点重金属浓度普遍比1号和2号采样点高。经7d暴露后,处理组和对照组中斑马鱼胚胎的孵化率、相对成活率和畸形率(畸形指标包括原肠胚终止、心跳/心率、脊柱畸形、心包囊水肿)均无明显差异;但幼鱼体内生殖相关基因(如α型雌激素受体,雄激素受体和芳香化酶)、甲状腺相关基因(如甲状腺激素受体、甲状腺激素释放激素、Ⅱ型脱碘酶)和神经发育相关基因(如α1微管蛋白、突触蛋白、生长相关蛋白)的转录水平较之对照组(曝气24h的自来水)均显著下降。上述结果表明,三峡库区水体中13种重金属的含量仍处于较低水平,且在此污染水平下不会对斑马鱼胚胎发育过程产生显著影响。此外,污染水体导致的分子水平上的变化是否会引起鱼类生长发育过程中的长期影响尚有待进一步研究。It has been obscure whether the pollution in the Three Gorges Reservoir （TGR） has impacts on the survival of fish that inhabit in the upstream of TGR, thus it is very important to monitor the pollution level and to investigate the toxic effects on fish early development. In this study, we collected surface water samples from three typical areas of the TGR, and employed the ICP-MS method to determine the concentrations of 13 typical heavy metals. We also evaluated the toxic effects by exposing zebrafish embryos （2h post-fertilization, hpf） to filtrated water samples until 168 hpf. The concentrations of 13 heavy metals in the TGR were all under the limits set by the environmental quality standards for surface water. We then examined the developmental endpoints, the transcription of several key genes in reproduction, in the synthesis of thyroid hormone, and in the neural development of fish. There were no significant differences in hatch- ing, survival, and deformity rates between embryos exposed to the TGR water and the control group. However, zebrafish larvae exposed to TGR surface water showed reduced transcription of genes involved in reproduction （er a, at, and cyp19b）, in the synthesis of thyroid hormone （trα, tsh β, and dio） and in the neural development （a1-tubulin, syn2a, and gap43）, and the water from site 3 had the most profound effects. Our results suggested that there might not be consi- derable heavy metal pollution in the surface water of the TGR, and that the early development of fish might not be af- fected at this pollution level. Further study is needed to test whether the molecular-level alteration may have long-term effects on the development of individual fish.

关 键 词：三峡库区 重金属 斑马鱼 发育毒性 

分 类 号：X171.5[环境科学与工程—环境科学]