Patmont Clay, Healy Rob
Anchor QEA, LLC, Seattle, Washington, USA.
Port of Tacoma, Tacoma, Washington, USA.
Integr Environ Assess Manag. 2024 Sep;20(5):1355-1365. doi: 10.1002/ieam.4890. Epub 2024 Jan 31.
The monitoring of completed large-scale sediment remediation projects has revealed mixed effectiveness at reducing risks, thus highlighting uncertainties regarding whether and which remedial measures are necessary to achieve protective goals. To support valid statements about changes over time and the overall effectiveness of sediment remedial action, robust pre- and postremediation monitoring is required with sufficient time points, reference sites, and biological metrics. The five completed Puget Sound sediment remediation case studies reviewed here (Bellingham Bay, St. Paul Waterway, Eagle Harbor, Hylebos Waterway, and Sinclair Inlet) employed particularly robust remedy effectiveness monitoring programs that spanned decades, revealing common lessons for improving remediation outcomes. First, although sediment remediation can play an important role in reducing contaminant exposure in areas with higher sediment concentrations, at lower levels, sediment links with fish tissue concentrations diminish. As water column exposure from diverse sources becomes predominant, remediating sediments with lower concentrations yields proportionately less risk reduction. Second, timely monitoring of effective source controls achieving substantial (i.e., >80%) contaminant source load reductions as well as large-scale capping projects have revealed rapid changes in Puget Sound surface sediment concentrations and biological recovery metrics with an average recovery half-time of 1.6 ± 0.8 years. The weight of evidence suggests that natural recovery of Puget Sound surface sediments is significantly accelerated by exchange across the sediment-water interface from benthic organism feeding behaviors, porewater flux, and tide-generated currents. As a result, effective source controls in Puget Sound have rapidly improved surface sediment quality and achieved more significant risk reductions than broadscale sediment remediation. Going forward, comprehensive Puget Sound source control efforts that incorporate robust monitoring in an adaptive management framework are the best way to achieve protective remediation objectives. These lessons may apply more broadly across similar complex urban aquatic ecosystems. Integr Environ Assess Manag 2024;20:1355-1365. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
对已完成的大规模沉积物修复项目的监测显示，在降低风险方面效果不一，这凸显了在实现保护目标方面是否需要以及哪些修复措施存在不确定性。为了支持关于随时间变化以及沉积物修复行动总体效果的有效陈述，需要进行强有力的修复前和修复后监测，要有足够的时间点、参考地点和生物学指标。这里回顾的五个已完成的普吉特海湾沉积物修复案例研究（贝灵汉湾、圣保罗水道、鹰港、海莱博斯水道和辛克莱湾）采用了特别强有力的修复效果监测计划，这些计划跨越了数十年，揭示了改善修复结果的共同经验教训。首先，尽管沉积物修复在降低沉积物浓度较高地区的污染物暴露方面可以发挥重要作用，但在较低水平时，沉积物与鱼类组织浓度之间的联系会减弱。随着来自各种来源的水柱暴露变得占主导地位，修复浓度较低的沉积物所带来的风险降低幅度相应较小。其次，对实现大幅（即>80%）污染物源负荷减少的有效源控制以及大规模覆盖项目的及时监测表明，普吉特海湾表层沉积物浓度和生物恢复指标迅速变化，平均恢复半衰期为1.6±0.8年。证据表明，底栖生物摄食行为、孔隙水通量和潮汐产生的水流在沉积物 - 水界面的交换显著加速了普吉特海湾表层沉积物的自然恢复。因此，普吉特海湾的有效源控制迅速改善了表层沉积物质量，并比大规模沉积物修复实现了更显著的风险降低。展望未来，在适应性管理框架中纳入强有力监测的全面普吉特海湾源控制努力是实现保护性修复目标的最佳途径。这些经验教训可能更广泛地适用于类似的复杂城市水生生态系统。《综合环境评估与管理》2024年；20:1355 - 1365。© 2024作者。《综合环境评估与管理》由威利期刊有限责任公司代表环境毒理学与化学学会（SETAC）出版。
