Human and ecological health risks from heavy metals and other substances released to the environment from metal shredders

The Minnesota Pollution Control Agency performed a first of its kind screening level human health and ecological risk assessment for a 100 ton per hour metal shredding facility. The results indicated that potential shredder emissions and releases of metals, in the form of particulates, could pose potentially unacceptable cancer and non-cancer risks to exposed humans and potentially unacceptable ecological risks to exposed plants and animals. Several air pollutants, particularly hexavalent chromium, lead, arsenic and beryllium, were found to be of potential human health and ecological concern. Increasing the automobile derived scrap metal component of the Kondirator feedstock increased the potential that health and ecological risks could be underestimated because of risks posed by coatings and other substances not evaluated in the risk assessments. This work has demonstrated that a facility initially represented as a minor risk to the environment may, because of its feedstock and location, be a potential significant risk to human health and the environment that must be mitigated by means of stringent pollution control permit conditions.