From time to time, concern is expressed about the possible detrimental effects of copper in rainwater run-off, particularly in countries where copper roofs, cladding, gutters and flashings are widely used.
Of the very small amounts of copper material carried in rainwater run-off, more than 95% are insoluble compounds held in suspension (rather than solution). These are not bio-available and become increasingly diluted in drains and watercourses, coming to rest in a mineral state as part of the earth’s natural background of copper material, continuing the extraction/mineralisation cycle.
The remaining available copper is taken up by organic matter in soil or at sewage treatment plants, or by other chemicals to form compounds with minimal, if any, amounts ultimately joining the natural background presence of copper in aquatic environments.
In any event, copper does not bio-accumulate, unlike some other metals such as lead, and it is well known that no harmful effects have occurred with the extensive use of copper plumbing in homes throughout the world.