Risks of hypoxia and acidification in the high energy coastal environment near Victoria, Canada's untreated municipal sewage outfalls

MARINE POLLUTION BULLETIN

卷:133

Article

Krogh, Jeremy^1,3  Ianson, Debby^1,2  Hamme, Roberta C.¹  Lowe, Christopher J.³ 

[1] Univ Victoria, Sch Earth & Ocean Sci, Victoria, BC V8W 2Y2, Canada

[2] Fisheries & Oceans Canada, Inst Ocean Sci, Sidney, BC, Canada

[3] Capital Reg Dist, Victoria, BC, Canada

关键词: Hypoxia;    Sewage outfall;    Ocean acidification;    Dissolved oxygen;    Victoria BC;   

DOI  :  10.1016/j.marpolbul.2018.05.018

来源: Elsevier

【 摘 要 】

Wastewater disposal often has deleterious impacts on the receiving environment. Low dissolved oxygen levels are particularly concerning. Here, we investigate the impacts on dissolved oxygen and carbon chemistry of screened municipal wastewater in the marine waters off Victoria, Canada. We analyzed data from undersea moorings, ship-based monitoring, and remotely-operated vehicle video. We used these observations to construct a two-layer model of the nearfield receiving environment. Despite the lack of advanced treatment, dissolved oxygen levels near the outfalls were well above a 62 mu mol kg(-1) hypoxic threshold. Furthermore, the impact on water column oxygen at the outfall is likely < 2 mu mol kg(-1). Dissolved inorganic carbon is not elevated and pH not depressed compared to the surrounding region. Strong tidal currents and cold, well-ventilated waters give Victoria's marine environment a high assimilative capacity for organic waste. However, declining oxygen levels offshore put water near the outfall at risk of future hypoxia.

【 授权许可】

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