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The water system provides many services to society; industries, municipalities and agriculture all withdraw, use and return water and demand a water quality fit for the intended purposes. Both global production of chemicals and global water withdrawal grow faster than human population. This implies increased chemical threats to water, and creates a strong driver for mitigation to protect human health, ecosystem integrity and ecosystem services. Here we connect the perspectives of the water cycle and the chemical life cycle and review possible mitigation options. We categorize mitigation options in various stages of the chemicals' life cycle, taking various sectors and environmental pathways into account. More technologically oriented versusother types of mitigation options are discerned, and their relevance on spatial and temporal scale is discussed. We review various water treatment techniques in relation to physical–chemical properties of chemicals. Finally we discuss how a mitigation database can be used to assess the effectiveness of interventions, by coupling them to regional or global hydrological models. A solution-focused and systems-oriented perspective combined with a mitigation database offers a common perspective amongst actors on the effects for water quality of possible mitigation options throughout the chemical's life cycle, in various sectors and at various places in the water system. This can stimulate coherent implementation of effective mitigation options, cross-sectoral learning and further innovations to improve water quality.

AbstractSeveral measures are available for reducing mercury emissions; however, these measures differ with regard to emission control efficiency, cost, and environmental benefits obtained through their implementation. Measures that include the application of technology, such as technology to remove mercury from flue gases in electric power plants, waste incinerators, and smelters, are rather expensive compared with nontechnological measures. In general, dedicated mercury removal is considerably more expensive than a co-benefit strategy, using air pollution control equipment originally designed to limit emissions of criterion pollutants, such as particulate matter, sulfur dioxide, or oxides of nitrogen. Substantial benefits can be achieved globally by introducing mercury emission reduction measures because they reduce human and wildlife exposure to methyl mercury. Although the reduction potential is greatest with the technological measures, technological and nontechnological solutions for mercury emissions and exposure reductions can be carried out in parallel.