Passive Sampling-Based versus Conventional-Based Metrics for Evaluating Remediation Efficacy at Contaminated Sediment Sites: A Review

Passive sampling devices (PSDs) are increasingly usedat contaminatedsites to improve the characterization of contaminant transport andassessment of ecological and human health risk at sediment sites andto evaluate the effectiveness of remedial actions. The use of PSDsafter full-scale remediation remains limited, however, in favor ofevaluation based on conventional metrics, such as bulk sediment concentrationsor bioaccumulation. This review has three overall aims: (1) identifysites where PSDs have been used to support cleanup efforts, (2) assesshow PSD-derived remedial end points compare to conventional metrics,and (3) perform broad semiquantitative and selective quantitativeconcurrence analyses to evaluate the magnitude of agreement betweenmetrics. Contaminated sediment remedies evaluated included capping,in situ amendment, dredging and monitored natural recovery (MNR).We identify and discuss 102 sites globally where PSDs were used todetermine remedial efficacy resulting in over 130 peer-reviewed scientificpublications and numerous technical reports and conference proceedings.The most common conventional metrics assessed alongside PSDs in thepeer-reviewed literature were bioaccumulation (39%), bulk sediments(40%), toxicity (14%), porewater grab samples (16%), and water columngrab samples (16%), while about 25% of studies used PSDs as the solemetric. In a semiquantitative concurrence analysis, the PSD-basedmetrics agreed with conventional metrics in about 68% of remedy assessments.A more quantitative analysis of reductions in bioaccumulation afterremediation (i.e., remediation was successful) showed that decreasesin uptake into PSDs agreed with decreases in bioaccumulation (withina factor of 2) 61% of the time. Given the relatively good agreementbetween conventional and PSD-based metrics, we propose several practicesand areas for further study to enhance the utilization of PSDs throughoutthe remediation of contaminated sediment sites.