facility were the chief sources of the pollution.

According to the report,"substantial economic injury results from the inability to market shellfish or shellfish products in interstate commerce because of pollution caused by sewage and industrial wastes discharged to the Penobscot River and upper Penobscot Bay area and action of state authorities." The WPCA noted that "accordingly the pollution of these navigable waters is subject to abatement under procedures described in Section 10 of the Federal Water Pollution Control Act,