Ecological Risk Assessment Process For the Ashland Harbor Site

The information below was presented by Wisconsin Department of Natural Resource's Jamie Dunn, and Mary Balcer of the Lake Superior Research Institute, on April 13, 2000, at the Our Lady of the Lake Church, in Ashland. It was prepared by W-DNR's Tom Janisch.

Contents:

Assessment and Measurement Endpoints
Measurement Endpoints (survival and growth)
Contaminants Of Concern (COC)
Consideration of Bottom Type or Substrates
Field Collections Performed
Toxicity Testing Performed
Laboratory Toxicity Testing
Sediment Chemical Concentrations and Bioassay Results
Ecological Relevance
Bioassay Results For Fathead Minnow
Photoactivation of PAHs
Bioassay Results From Exposure of Test Organisms to Ultraviolet Light
Comparison of Population Indices
Field and Laboratory Water Column Concentrations
Water Concentrations of Total PAHs
Analysis in Fillets and Whole Fish Collected

• The purpose of the ecological risk assessment (ERA) was to estimate the current and future risks and impacts from contaminants of concern present in the surface waters and sediments of the site to benthic macroinvertebrates, fish and other aquatic organisms that normally occupy or use the site habitats and birds and wildlife that may utilize the habitats as part of their foraging base.


• A weight-of-evidence approach was used to examine the biological impacts of the co-occuring coal tar contaminants (e.g. PAHs, VOCs, and heterocyclic aromatic compounds) originating in coal tar oils and residuals and characterize site risks. Several types of data were developed to provide supporting information for the risk assessment that included:

1. Fish, water column, and benthic test organisms were exposed to sediments and water collected from contaminated harbor sites and clean sites in a series of laboratory toxicity tests.
2. Bottom sediments were collected from the contaminated sites and clean sites and examined in the laboratory to look at the number and diversity of bottom-dwelling species present.
3. The results of studies in the literature conducted at other contaminated sediment sites with the same types of contaminants as the Ashland site were reviewed and applicability determined.
4. Published guidelines or criteria that relate sediment and water concentrations of the contaminants to effects to benthic organisms, fish, and other aquatic organisms were compared with the measured concentrations of contaminants in the sediments and water found at the Ashland site.

The results of each of the above study components contributes lines of evidence, that when integrated and weighted for certainty, contributes to the weight-of-evidence that allows arriving at conclusions about the ecological risks present at the site.