This trend is likely to continue, albeit at a low rate for many substances. This is due to their extremely slow degradation and ability to be transported far from initial sites of emissions and releases. Many substances can be released from products even during their use and long after their disposal. Awareness of the environmental impacts of substances released by human activities is much higher today than it was just a few decades ago. Future concentrations of contaminants in the environment and biota are highly dependent on human activities. Restrictions, substitutions and bans can, in the long term, reduce concentrations of many substances. It should be kept in mind that for some contaminants, especially those easily transportable over long distances, restrictions should be made globally in order to achieve the objectives of