Inputs and concentrations of metals in water

Heavy metals such as mercury, cadmium and lead are toxic to marine organisms in relatively low concentrations. Inputs of heavy metals to the marine environment from riverine sources and direct discharges (sewage and trade effluent) are estimated as total annual inputs using information of river flow and metal concentrations. Monitoring of contaminant concentrations in coastal and transitional (estuaries) waters is a requirement of the Water Framework Directive (2000/60/EC) where data from water bodies are compared against contaminant concentrations known to impact on the marine environment (environmental quality standards).