A STUDY OF THE POLLUTION LEVELS AND DEPTHS WITHIN SUBSURFACE CORES COLLECTED DURING PRELIMINARY INVESTIGATIONS FOR THE PROPOSED ARROWHEAD BRIDGE

Abstract

In a study completed in December 1973 by National Biocentric, Inc.· of Saint Paul for the U.S. Army Corps of Engineers, sediments collected during the preceding summer within the Duluth-Superior harbor at the water-sediment interface were declared polluted as measured against then, and still, existing Environmental Protection Agency guidelines regulating dredge spoil material. The location of sample sites used in the Corps study and a comparative sche­matic of analysis results, where EPA standards exist (along with a comparison to the Ashland, Wisconsin harbor), are presented on the following two pages.