This report is based on research and progress addressing concern that copper released from copper roofs enters the groundwater, rivers, lakes and causes harm to fish and other aquatic organisms. Most metals are of natural origin and a fundamental component of the earth's crust. Copper is no exception, and in addition, is essential to the health of all living organisms.
All life forms have a requirement for copper.
The essential question is not whether copper is toxic but whether the copper runoff from roofs can increase concentration of copper in lakes, streams and groundwater to such high levels as to become a hazard. Newly installed copper roofs immediately begin to weather and oxidize. This weathering process actually produces a self protective coating on the copper called a patina. It is complex, very durable and extremely stable. It is the chemistry of the atmosphere and particularly of dew, especially its degree of acidity, that determines if any of the patina surface is dissolved.