Monitoring chemical and biological recovery at a confined aquatic disposal site, Oslofjord, Norway

Abstract

The recovery of the confined aquatic disposal (CAD) facility located at Malmøykalven in Oslofjord, Norway, has been assessed using an array of field measurement techniques. These methods were used prior to the disposal of dredged sediments as well as during 3 annual postdisposal monitoring campaigns. Traditional sampling to assess chemical recovery indicates that an immediate reduction in total sediment concentrations and surface sediments can be characterized as having good quality. Deposition of new material indicates that the quality of depositing material at the CAD is stabile and representative of the natural background quality in the area. Continued deposition of this material will improve the long-term chemical recovery of the CAD. A positive biological recovery of the benthic community has been observed and is expected to continue along a typical benthic succession pattern. To supplement traditional sampling, passive samplers were deployed at the CAD. Results suggest that the flux and concentrations of polycyclic aromatic hydrocarbon 16 and polychlorinated biphenyl 7 released from the CAD will continue to decrease over time. The combined results from these multiple lines of evidence indicate that the CAD and capping layer function as predicted 3 yr after the construction was completed. There is not only an improvement in the efficacy of the CAD itself but also a general improvement of the area, compared with the situation prior to disposal. Environ Toxicol Chem 2017;36:2552-2559. © 2017 SETAC.

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

“…Minick and Anderson used a rugged stainless-steel probe to encase PRC-loaded LDPE samplers and drive them into a sand and organoclay isolation cap topped with armoring stone at the McCormick and Baxter Creosote Superfund Site within the larger Portland Harbor Superfund Site (Oregon, USA). Oen et al used benthic flux chambers equipped with SPMD as an infinite sink and also deployed POM samplers in the water column for 77–86 days to investigate the long-term chemical stability of a capped CAD in Oslo Harbor, Norway. They also collected bulk sediment and overlying sediment from sediment traps prior to and after disposal and capping.…”

Tailored Leaching Tests as a Tool for Environmental Management of Mine Tailings Disposal at Sea

“…There are, however, historical examples of particle dispersion [20], pollutant leaching [21,22] and bioaccumulation [23] outside the disposal areas. In order to limit these effects, actions are often taken to stabilize pollutants and particles in confined aquatic disposal of polluted dredge sediment, e.g., by capping with a clean material [24]. Upon cessation of mine tailings disposal, actions to stabilize particles and pollutants have not been a common practice.…”