Emissions of heavy metals to surface water by companies

Metals are non-degradable and (bio)accumulate in the aquatic environment. Some of them are essential for various biochemical processes in organisms. At higher concentrations, they can become toxic to aquatic organisms. Gross emissions are discharges at the site. Net emissions take into account any treatment at a public sewage treatment plant.Companies account for a small share of net emissions to surface water for most metals.Both gross and net emissions of heavy metals by companies have decreased.