Research Programs: Contaminated Sediments
Research Areas: Benthic Recovery

Contaminated Sediments

How to assess benthic status at contaminated sediment Superfund sites?

Background

Photo of EPA scientist sorting animals from a sediment core

Counting and identifying organisms collected in sediment cores is labor intensive but highly informative.

EPA needs cost-effective, rapid methods to assess benthic status before and after remedial actions and to separate the effects of chemical contamination from other stressors on the benthic community. Two methods are commonly used to assess the status of the benthic community, each with its own advantages and disadvantages. The traditional method, benthic organism enumeration, requires the collecting and sieving of sediment followed by identifying and counting the retained organisms. While this method yields detailed information on species richness and biomass, it is labor intensive, slow, and comparatively expensive. Remote sensing of the benthos using sediment profile image (SPI) cameras provides a rapid spatial assessment of the benthic community in situ and is relatively inexpensive, but does not provide quantitative or comprehensive species counts.

Problem

Sediment Profile Imaging camera (SPI). View a photo taken by SPI. (large photo - 104 kb)

Widespread skepticism concerning the SPI approach exists among many benthic ecologists who conduct studies using the traditional sediment collection/sieving approach. In addition to standardization and quality assurance work on the SPI approach, the following questions need to be addressed:

Do the speed, increased spatial coverage, and reduced costs associated with the SPI approach provide enough information to assess adequately remedial effects and effectiveness compared with the traditional enumeration procedures?
What is the most appropriate use of SPI images at Superfund sites? and
Which metrics/indices to calculate from the data and how best to utilize both methods (e.g., alone or in combination) and their metrics?

Approach

The research will:

Evaluate the SPI camera as a rapid and cost-effective tool to assess the short-term effects on and recovery of the benthic community after dredging at a Superfund site;
Evaluate and compare benthic community data obtained using SPI with more traditional collect/sieve metrics; and
Investigate interactions between sediment contaminants and near-bottom dissolved oxygen concentrations and their relative influence on benthic community recovery.

View a time-lapse SPI movie and learn more about SPI