Halting emissions of pollutants to soils and waters

Diffuse emissions of pollutants from land and urban sources, including atmospheric depositions, are a major stress factor for terrestrial and aquatic ecosystems, threatening the quality of surface waters and aquifers, and affecting soil quality and all water-dependent sectors that require a holistic understanding of the pollution sources, key vectors and pathways

While recognising its essential role in aquatic ecosystems functioning and services, the sediments originating mostly from run-off and erosion are likely the major source of physical pollution of water bodies  and contribute to a large extent to chemical and biological pollution of receiving waters. Beside land use practises, the increasing intensity and variability of precipitation will exacerbate erosion risks, affect the deposition and transport of sediments and could lead to a remobilisation of legacy contaminants and further deteriorate the quality of soils and water bodies, including aquifers, estuaries and coastal areas, and of their ecosystem function and services.

Keeping nitrogen (N) and phosphorus (P) cycles in balance is another crucial challenge. N and P flows from anthropogenic sources, mostly from excessive or inefficient input of fertilisers in agriculture, currently exceed planetary boundaries. Their leaching and run-off negatively affect soil biodiversity, pH, organic matter concentration and carbon sequestration capacity, and cause the eutrophication of water bodies while ammonia and nitrous oxide emissions affect air quality and climate.

As all environmental media are concerned, a systemic approach is necessary to limit N/P emissions from different sources, for example through the deployment of alternative fertilising products, and considering regional conditions (geography, climate zones, economy activities, soil properties, eco-system condition, agricultural practices, governance structures etc.), and to bring N/P flows back within safe ecological boundaries