The U.S. Geological Survey is making a river-quality assessment of the Schuylkill River basin in Pennsylvania from October 1978 to March 1981. It is part of a continuing program designed to demonstrate the effectiveness of river-quality studies for basin planning and water-resource management. Study objectives include determining (1) presence of selected trace metals and organic substances in the water and sediments of the Schuylkill River between Berne and Philadelphia; (2) source, distribution, and transport of selected trace metals and organic substances in the river from Berne to Philadelphia; (3) frequency of occurrence of selected trace metals and organic substances in the river at Pottstown and Manayunk; (4) effects of low dams on the distribution and transport of selected trace metals and organic substances in the river between Pottstown and Philadelphia.