Recovery of fish populations in response to major infrastructure investments at municipal wastewater treatment plants

点击翻译按钮获取中文摘要

Concern over the potential impacts of wastewater across Canada has been heightened by recent reports of a variety of emerging contaminants of concern being released into the environment. These diverse chemicals have the potential to disrupt the normal function of endocrine systems and impair reproduction and development in fish and other organisms. Although considerable research has been focused on this issue worldwide, the chemicals and mechanisms responsible for the effects observed downstream of wastewater water treatment plant outfalls remains mostly undetermined. This proposal will examine the impact of major process upgrades at wastewater treatment plants in the Grand River, Ontario, on a sentinel fish species. Previous studies on rainbow darter (Etheostoma caeruleum) in this watershed have identified adverse biological impacts including altered gene expression, the occurrence of intersex (testis-ova), alterations in reproductive physiology (e.g. reduced gonad size and steroid production), reproductive performance (e.g., fertilization success) and community assemblages. Thus there is a multiyear baseline from which to make comparisons as upgrades are implemented over the next several years. This research will compare the responses in fish across these multiple levels of biological organization after process changes at several wastewater treatment plants within the same watershed. This will allow assessment of how various endpoints respond temporally and spatially to major changes in effluent quality. It will advance our understanding of the fate of contaminants (including endocrine disrupting compounds) and the linkages among various levels of biological organization leading to adverse outcomes that are key endpoints in assessing risk. Understanding of these processes and linkages are central to the development of predictive cumulative effects assessment frameworks for watersheds. The research will apply and assess the validity of emerging monitoring tools/approaches (e.g. next generation sequencing) that will allow water managers in many sectors to assess and prioritize stressors and remedial options for the future.