The Risk To Health of Chemicals in Sewage Sludge Applied To Land

Abstract

A Working Group organized by the World Health Organization, Regional Office for Europe, considered the risk the health of chemicals in sewage sludge applied to land. Cadmium appears to be the most important contaminant because it can be accumulated from the soil by certain food plants. Other metals in sludge are unlikely to cause health problems if sludge applications do not exceed the nitrogen requirements of the crops. Organic pollutants such as pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons are not significantly absorbed by plants through their roots but may be ingested with soil by some grazing animals. The total human intake of identified organic pollutants from sludge application to land is minor and is unlikely to cause adverse health effects. The influence of soil properties on plant uptake of cadmium is reviewed since current limits for cadmium in soils and sludge vary greatly between different countries.