Project 9:

Improving Ecological Risk Assessment: Development and Application of Methods to Determine the Bioavailability of Contaminants in Aquatic Sediments

Project leader: James Shine
Project co-leaders: Timothy Ford, P. Barry Ryan

Background:

The amount of contaminants in an environment cannot predict the potential harmful effects for animals and plants in the environment or for human health. The contaminants undergo many interactions within the environment. An understanding of how contaminants move through the environment and are taken-up by plants, animals, and humans (the processes referred to as fate and transport) helps us understand their toxicity and potential impact in ecological and human health.

Specific aim:

The goal of this project is to improve our understanding of 1) what determines the fate of contaminants in aquatic environments, and 2) their potential to impact human health. As a result of this research, we hope to develop better tools for determining the risk posed by these contaminants.

Methods:

This study is being conducted at seven sites: three locations in New Bedford Harbor, (New Bedford, MA, a U.S. EPA Superfund site); one location in Boy’s Creek (Fairhaven, MA, a U.S. EPA Superfund site); and three locations in Boston Harbor (Boston, MA).

The researchers are evaluating the effectiveness of an approach called equilibrium partitioning to estimate the degree to which polycyclic aromatic hydrocarbons (PAHs) in sediment can be absorbed by biological systems. To accomplish this evaluation, we will test to determine the following:

• Total PAHs in the sediment
• PAHs taken up by semi-permeable membrane devices (SPMDs)
• PAHs taken up by the test organisms
• The amounts of organic and soot-phase carbon in sediment
• The ratio of PAHs present from combustion sources vs. spill sources

The researchers are also testing the importance of organic carbon and sulfides as factors that control the degree to which metals in sediment can be absorbed by plants, animals, and humans. They are developing and employing a device similar to the SPMD that will function to absorb metals in a controlled manner, in the same way that the SPMDs absorbs PAHs.

Results:

• We have developed new models to demonstrate the behavior of PAHs in aquatic environments and the risks that they pose. We have determined the importance of the presence of black carbon in determining the ability of PAHs to be taken up by biological organisms.
• We have determined that polyethylene devices (PEDs) can mimic the uptake of PAHs by organisms living at the bottom of water bodies.
• We have developed a tool to measure metal absorption called the “Gellyfish.” The Gellyfish can take up metals in correlation to mussel uptake of metals.

Recent publications:

• Senn, D.B., S. Griscom, C. Lewis, J. Galvin, M. Chang, and J. Shine, J. 2004. Equilibrium sampler for determining copper free metal ion concentration. Env. Sci. Technol. 38): 3381-3386.

• Vinturella, A.E., R.M. Burgess, B.A. Coull, K.M. Thompson, and J.P. Shine. 2004. The use of passive samplers to mimic uptake of PAHs by benthic polychaetes. Env. Sci. Technol. 38:1154-1160.

• Vinturella, A.E., R.M. Burgess, B.A. Coull, K.M. Thompson, and J.P. Shine. 2004. The importance of black carbon in equilibrium partitioning models of PAHs in contaminated marine sediments. Env. Toxicol. Chem. 23: 2578-2586.