Assessment and Management of Historical Pulp Mill Releases to a Marine Embayment - How Toxic are the Sediments and What Makes Them Toxic?, 1999 Environmental Conference Proceedings

Lucinda Jacobs & Scott Becker

Exponent

John A. Maloy

Ketchikan Pulp Company

As required by the U.S. Environmental Protection Agency, a sediment investigation was conducted in Ward Cove, Alaska, for the Ketchikan Pulp Company to determine the potential threat to human health and the environment posed by sediment adjacent to the mill. Historical releases of pulping by-products and log handling activities in Ward Cove resulted in a complex mixture of chemicals and partially digested organic matter in sediments near the mill. Based on an integrated analysis of site-specific data on sediment chemistry and sediment toxicity, it was concluded that the natural degradation products of organic matter were likely responsible for the observed toxicity to benthic organisms. Measurable toxicity was limited and could be explained largely by the life histories and behavioral patterns of the organisms tested. An analysis of case studies of similar, organically enriched environments suggests that natural recovery is a viable remedial alternative for organic-rich sediment and that active remediation, if conducted at all, should be limited to thin capping. Conclusions regarding sediment toxicity are also relevant to log handling facilities, which are coming under increasing regulatory scrutiny.