Heavy metal contamination of fresh water: implications for pollution control policy

Abstract

Persistent toxic substances have been identified as a problem in the aquatic environment because of their unique chemical characteristics. Heavy metals are a good example of persistent toxic substances. The presence of heavy metals in fresh water poses a threat to human health, the viability of certain industries, and the stability of aquatic ecosystems. This Master's Degree Project examines the ability of institutional frameworks to control the pollution of fresh water by heavy metals, given their unique characteristics as persistent toxic substances and their release from both point and non-point sources. The metals examined are cadmium, lead, and mercury. The institutional frameworks of the federal government and the provincial governments of Alberta, Manitoba, and Ontario are reviewed with respect to policy instruments and management approaches. This review is based on the issues identified from an examination of the chemical characteristics of cadmium, lead, and mercury in fresh water and aquatic ecosystems, and of the point and non-point sources of metals to the aquatic environment. The review identifies the following issues as important to the management of persistent toxic substances: a lack of policy specific to persistent toxic substances; limited ecosystem monitoring; misapplication of assimilative capacity; a need for zero discharge and ecosystem management approaches; and the need to integrate human health issues into water quality management frameworks.