Roof Runoff as a Diffuse Source of Metals and Aquatic Toxicity in Storm Water

Results are reported on the concentrations of dissolved and total copper, lead, and zinc, hardness, and pH value of the first flush of run-off from roofs at a sawmill during a storm following 8 d of dry weather. The percentage survival from acute toxicity tests on rainbow trout is also tabulated. Details of sampling locations and sampling procedures are included. Galvanized metal roofs were a major source of zinc in the storm water, and run-off from these roofs was highly toxic to the fish. Tar-covered roofs were a source of copper, and plastic rain gutters were a source of lead. The concentrations of dissolved metals and the toxicity were high in a run-off sample collected 3 h after the storm began. Materials that did not leach metals should be used in replacement of new roofs, to reduce the polluting effect of run-off.