Spatiotemporal trends for polychlorinated biphenyls (PCBs) were examined in surface and suspended sediments collected between 1994 and 2018 from over twenty nearshore stations on the Canadian side of Lake Ontario and the St. Lawrence River. In 2018, PCB concentrations ranged over an order-of-magnitude in surface (<10 ng/g−357 ng/g) and suspended sediments (<10 ng/g–330 ng/g), illustrating the presence of legacy hotspots as well as diffuse urban inputs. PCB concentrations in both surface and suspended sediments were consistently highest in Hamilton Harbour, but were also elevated at other stations around the perimeter of the Niagara basin as well as near Trenton and Kingston, Ontario. Generally, higher PCB concentrations were found in surface sediment relative to paired suspended sediment samples suggesting temporal improvements in nearshore sediment quality. However, many stations demonstrated temporal variability in PCB concentrations, a likely factor in the lack of an overall nearshore declining trend. Given that PCBs are listed as a consumption-limiting contaminant for all fish sampling blocks in the Canadian waters of Lake Ontario and are responsible for 78% of restricted advisories, sediment quality benchmarks that account for bioaccumulation potential should be considered over toxicologically-derived guidelines to gauge severity of PCB contamination of nearshore sediments. Relatively higher TOC-normalized PCB concentrations in the western end of Lake Ontario suggests additional research on PCB bioavailability from nearshore sediment would be beneficial in understanding basinwide trends of PCBs in fish, and that an adaptive approach to sediment management may be needed in the context of consumption advisories.

研究了 1994 年至 2018 年间从安大略湖加拿大一侧和圣劳伦斯河的 20 多个近岸站收集的地表和悬浮沉积物中多氯联苯 (PCB) 的时空趋势。2018 年，地表（<10 ng/g-357 ng/g）和悬浮沉积物（<10 ng/g-330 ng/g）的 PCB 浓度范围超过一个数量级，说明遗留热点的存在以及分散的城市投入。汉密尔顿港表面和悬浮沉积物中的 PCB 浓度一直最高，但在尼亚加拉盆地周边以及安大略省特伦顿和金斯敦附近的其他站点也有所升高。一般来说，相对于成对的悬浮沉积物样品，在表层沉积物中发现了更高的 PCB 浓度，这表明近岸地区的时间有所改善沉积物质量. 然而，许多站点表现出多氯联苯浓度的时间变化，这可能是缺乏整体近岸下降趋势的一个因素。鉴于多氯联苯被列为加拿大安大略湖水域所有鱼类采样区的消费限制污染物，并负责 78% 的限制性建议，因此应考虑考虑生物累积潜力的沉积物质量基准，而不是毒理学衍生的准则测量近岸沉积物 PCB 污染的严重程度。安大略湖西端相对较高的 TOC 归一化 PCB 浓度表明，对近岸沉积物中 PCB 生物有效性的进一步研究将有助于了解全流域鱼类中 PCB 的趋势，