Superfund Research Program
Improving Ecological Risk Assessment: Development and Application of Methods to Determine the Bioavailability of Contaminants in Aquatic Sediments - New Bedford SF Site
Project Leader: James P. Shine
Grant Number: P42ES005947
Funding Period: 1995 - 2006
The objectives of this project are two-fold – to improve our understanding of the mechanisms controlling the fate and effects of contaminants released to aquatic ecosystems, and to develop analytical tools that provide appropriate data to test the ability of these models to assess risk.
With respect to metals, Dr. Shine’s primary activity has been to develop and test a sampler that can directly measure metal speciation in aquatic ecosystems. The sampler, termed the “Gellyfish”, consists of a thin film of polyacrylamide gel impregnated with a metal binding resin (Tosohaas toyopearl). Dr. Shine has conducted field studies using these devices to examine spatial and temporal variability of free copper ion concentrations in Boston Harbor.
In addition, Dr. Shine’s research group is also measuring aquatic chemical parameters such as total dissolved copper, chlorophyll, salinity, and dissolved organic carbon (DOC) to determine the extent that these may be predictors of free metal ion concentration. Over the course of the last year, the researchers have taken approximately 250 measurements of free copper at 5 stations in Boston Harbor. Their results show that the concentration of free copper ion is negatively correlated with DOC, and that the variability seen over time at one station is approximately equal to the variability between different stations sampled at the same time. In total, this data can be used to assess the amount of sampling (in both time and space) required to adequately assess metal stress in a coastal estuary such as Boston Harbor.
A second application has been to examine the ability of the Gellyfish samplers to mimic the uptake of metals into aquatic organisms. Dr. Shine’s group has completed a large study in which they co-deployed Gellyfish with mussels (Mytilus edulis) at various locations in Boston Harbor and Massachusetts Bay. The results of the study indicate that for metals such as lead, copper, and zinc, the amount of metal accumulated by the Gellyfish is significantly correlated with metal concentrations in mussels. Because Gellyfish deployments are much less expensive than deployment of live mussels, they are therefore a valuable substitute for mussels when financial resources for monitoring are limited. Dr. Shine’s team has created a model that guides environmental decision makers on the optimal design strategy (use of mussels, Gellyfish, or a combination of the two) to best capture spatial and temporal changes in coastal marine pollution. When applied to data from current monitoring programs, it is often the case the optimal strategy is to use mostly the inexpensive Gellyfish rather than live organisms.