Function of a landscape lake in the reduction of biotoxicity related to trace organic chemicals from reclaimed water

• Published in: Journal of hazardous materials 2016-11, Vol.318, p.663-670
• Main Authors: Ma, Xiaoyan Y., Wang, Xiaochang C., Wang, Donghong, Ngo, Huu Hao, Zhang, Qiuya, Wang, Yongkun, Dai, Dinan
• Format: Article
• Language: English
• Subjects: Animals; Biological Oxygen Demand Analysis; Biotoxicity; Ecological safety; Ecology; Ecosystem; Lakes; Landscapes; Mutagenicity Tests; Mutagens - toxicity; Open storage; Organic Chemicals - toxicity; Organic chemistry; Reclaimed water; Reclamation; Reduction; Reuse; Risk Assessment; Toxicity; Trace organic chemicals; Water Microbiology; Water Pollutants, Chemical - toxicity; Water Pollution, Chemical - adverse effects; Water Purification; Zebrafish
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.07.050

[Display omitted] •The lake is a buffer zone in between reclaimed water production and reuse.•Biotoxicity of reclaimed water decreased during open storage in a landscape lake.•The dominating chemicals contributing to the biotoxicity were identified.•The lake provided a favorable seminatural condition for micropollutants decay. The storage of water in a landscape lake can act as a buffer zone between reclaimed water production and reuse, but there is still uncertainty about the variation of water quality and toxic effects during the open-storage process. In this study, long-term sample collection, chemical analyses and biotoxicity assessments were conducted on reclaimed water before and after open storage in a landscape lake. The organic contents, in terms of chemical oxygen demand and total organic carbon, were found to be slightly higher in the lake water than that in the reclaimed water, but substantial reduction of the total concentration of 52 trace organic chemicals was obtained and microorganism toxicity, phytotoxicity, aquatic vertebrate toxicity and genotoxicity, were significantly weakened after open storage. Furthermore, the total risk quotient (RQTotal) decreased from 5.12 (potential ecological risk level) in the reclaimed water to 0.18 (negligible ecological risk level) in the lake water. The removal of chlorpyrifos, dichlorphos and tetracycline was identified as the main reason for biotoxicity reduction after open storage. The seminatural environment of the landscape lake would have provided a favorable condition for the decay of toxic trace organic chemicals so that the stored water turned to be safer for further reuse.