Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, ON, Canada.
Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, ON, Canada.
Environ Pollut. 2017 Jun;225:460-468. doi: 10.1016/j.envpol.2017.03.010. Epub 2017 Mar 18.
Global human population and urbanization continually increase the volume of wastewater entering aquatic environments. Despite efforts to treat these effluents, they contribute a diverse suite of substances that enter watersheds at concentrations that have the potential to elicit adverse effects on aquatic organisms. The relationship between wastewater treatment plant (WWTP) effluent exposure and biological responses within aquatic ecosystems remains poorly understood, especially at the population level. To examine the effect of WWTP effluents on sentinel invertebrates, freshwater mussels were assessed in the Grand River, Ontario, in populations associated with the outfall of a major WWTP. This watershed, within the Laurentian Great Lakes basin, has a diverse community of twenty-five species of mussels, including nine Species at Risk, and is representative of many habitats that receive WWTP effluents regionally as well as globally. Surveys were conducted to assess the presence and species richness of freshwater mussels. In total, 55 sites downstream of the WWTP were examined using timed visual searches with one or 2 h of effort spent searching 100 m segments. Although seven species of mussels were found in moderate abundance (mean of 8 mussels per hour of searching across 2 sites) upstream of the WWTP outfall, no live mussels were observed for 7.0 km downstream of the WWTP. Long-term water quality monitoring data indicate that ammonia and nitrite concentrations along with large seasonal declines in diel dissolved oxygen were associated with the extirpation of mussels downstream of the WWTP. The first live mussels found downstream were below the confluence with a major tributary indicating that in addition to an improvement in water quality to a state that enables mussels (and/or their fish hosts) to survive, a nearby mussel refuge may have facilitated the recolonization of the depauperate WWTP-impacted zone.
全球人口和城市化进程不断增加进入水生环境的废水总量。尽管人们努力处理这些废水，但它们仍会带来各种物质，这些物质以可能对水生生物产生不利影响的浓度进入流域。污水处理厂 (WWTP) 废水暴露与水生生态系统内生物反应之间的关系仍知之甚少，尤其是在种群水平上。为了研究 WWTP 废水对指示无脊椎动物的影响，在安大略省格兰德河上评估了淡水贻贝，这些贻贝存在于一个主要 WWTP 的出水口相关的种群中。该流域位于大湖流域的劳伦斯大湖区内，拥有 25 种贻贝的多样化社区，包括 9 种濒危物种，并且代表了许多接收 WWTP 废水的栖息地，无论是在区域内还是全球范围内。进行了调查以评估淡水贻贝的存在和物种丰富度。总共检查了 WWTP 下游的 55 个地点，使用定时视觉搜索，在 100 米的片段上花费 1 或 2 小时进行搜索。尽管在 WWTP 出水口上游发现了七种贻贝的中等丰度（在 2 个地点每小时搜索 8 只贻贝），但在 WWTP 下游 7.0 公里处没有观察到活贻贝。长期水质监测数据表明，氨和亚硝酸盐浓度以及昼夜溶解氧的大幅季节性下降与 WWTP 下游贻贝的灭绝有关。在 WWTP 与主要支流汇合处下游发现的第一批活贻贝表明，除了水质改善到使贻贝（和/或其鱼类宿主）能够生存的状态外，附近的贻贝避难所可能促进了贫化 WWTP 影响区的再殖民化。
