摘要:
有毒化学物质排放引起的水质污染可以用暴露后水生生物的生物学响应来监测预警。本文利用2013年7月份广东某水源流域发生的一次突发污染物事件作为案例分析,讨论在线生物预警技术在实际应用中的效果及存在的问题。研究结果表明,采用发光菌抑制和鱼类行为改变的生物预警技术均能够有效判别突发性污染事件。结合预警后的采样和化学分析,18种金属元素和114种有机污染物监测指标中,所有指标的浓度均低于国家地面水水质II类标准(GB3838-2002)。在能够检出的金属元素和有机污染物中,超出检出限最大的金属元素是钡,达到检出限的870倍;超出检出限最大的有机物是二氯甲烷,是检出限的145倍。根据文献发表的毒性数据和毒理学证据,推测本次案例研究中的二氯甲烷是潜在的污染因子;二氯甲烷通过其神经毒性和较强烈的嗅味影响到青鳉鱼的运动行为、导致报警。另外,文章分析了生物监测技术的优点和缺陷,以期为进一步开发水源污染生物预警系统提供基础数据。
Abstract:
Water pollution incident caused by toxic chemicals could be monitored by biological responses of toxic substances when exposed to aquatic organism. In this paper, a case study using biological early warning device for toxic pollution was carried out based on a real field observation of pollution incident happened in July, 2013. Through this case analysis, we demonstrated that both of the device based on bioluminescentinhibition of photobacteria (TOXcontro,Netherlands) or that based on behavior change of fish (BEW, China) could detect the pollution event. Our results showed that both toxic devices based on luminescent inhibition and behavior changes of fish could detect the chemical incident effectively. With chemical analysis of 18 metals and 114 organic contaminants for samples taken after pollution events,we found that all measured pollutants were in concentration levels lower than the Type-II Surface water thresholds of the National Standard for Chemicals (GB3838-2002). Among the detectable chemicals, barium exceeded the detection limit by 870 folds and dichloromethane was 145 times of the detection limits. Based the literature survey, we suggested that dichloromethane could be the cause for this pollution event due to its neurotoxicity and lower smell threshold. Dichloromethane may induce abnormal behavior of fish through stimulation of its nerve system or result in the avoidance. Advantage and weakness of the biological monitoring technology were discussed on experiences of the case study, as to provide the data base for further exploration of biological early-warning system.
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