In this study, we conducted a retrospective analysis of the spatio-temporal trends of fish contamination in the Canadian Great Lakes. We subsequently formulated consumption advisories that explicitly account for all sources of uncertainty, such as model error, sampling bias, and natural variability of fish assemblages. Our analysis generated exceedance frequency maps of the tolerable daily intakes (TDIs), which showed that mercury (Hg) concentrations are generally at a safer level for consumption, whilst polychlorinated biphenyls (PCBs) continue to result in restrictive advisories. Specifically, the initial decline in PCBs has transitioned into a steady state, possibly due to the combined effects of external contamination sources and internal abiotic and biotic factors. Our assessment of the PCB decline rates required to comply with TDI thresholds over the next twenty years suggest that a small degree of reduction is needed for Walleye (Sander vitreus) across all sampled sites, whereas much faster decay rates are needed for Lake Trout (Salvelinus namaycush), especially in lower Lake Huron, Lake Erie, and Lake Ontario. We also detected a distinct Hg gradient whereby the southernmost waterbody, Lake Erie, had the lowest average concentrations, whereas the highest levels amongst the fish species sampled were registered in St. Lawrence River. Finally, we show the ability of our Bayesian approach to fish consumption advisories to produce time-specific, highly customizable, risk-assessment statements that account for the inherent variability in natural fish communities and the variant degree of empirical evidence about the contamination history in different locations around the Great Lakes.

在这项研究中，我们对加拿大五大湖鱼类污染的时空趋势进行了回顾性分析。我们随后制定了明确说明所有不确定性来源的消费建议，例如模型误差、抽样偏差和鱼类组合的自然变异性。我们的分析生成了每日可耐受摄入量 (TDI) 的超标频率图，表明汞 (Hg) 浓度通常处于更安全的消费水平，而多氯联苯 (PCB) 继续导致限制性建议。具体而言，多氯联苯的最初下降已经过渡到稳定状态，这可能是由于外部污染源和内部非生物和生物因素的综合影响。Sander vitreus ) 在所有采样地点，而鳟鱼湖 ( Salvelinus namaycush )需要更快的衰减率，尤其是在休伦湖下游、伊利湖和安大略湖。我们还检测到明显的 Hg 梯度，最南端的水体伊利湖的平均浓度最低，而采样的鱼类中最高浓度记录在圣劳伦斯河。最后，我们展示了我们的贝叶斯方法对鱼类消费建议的能力，以产生特定时间、高度可定制的风险评估陈述，这些陈述解释了天然鱼类群落的固有变异性和不同程度的污染历史经验证据的变异程度。五大湖周边地区。