Nutrient pollution

Environmental and economic impacts (Add more in depth paragraphs for the impacts of nutrient pollution rather than bullet points) Excess nutrients have been summarized as potentially leading to: • Excess growth of algae (harmful algal blooms); and biodiversity loss; • Species composition shifts (dominant taxa); • Food web changes, light limitation; • Excess organic carbon (eutrophication); dissolved oxygen deficits (environmental hypoxia); toxin production; Health impacts Human health effects include excess nitrate in drinking water (blue baby syndrome) and disinfection by-products in drinking water. Swimming in water affected by a harmful algal bloom can cause skin rashes and respiratory problems. == Reducing nutrient pollution ==

Nutrient trading Nutrient trading is a type of water quality trading, a market-based policy instrument used to improve or maintain water quality. The concept of water quality trading is based on the fact that different pollution sources in a watershed can face very different costs to control the same pollutant. Water quality trading involves the voluntary exchange of pollution reduction credits from sources with low costs of pollution control to those with high costs of pollution control, and the same principles apply to nutrient water quality trading. The underlying principle is "polluter pays", usually linked with a regulatory requirement for participating in the trading program. A 2013 Forest Trends report summarized water quality trading programs and found three main types of funders: beneficiaries of watershed protection, polluters compensating for their impacts and "public good payers" that may not directly benefit, but fund the pollution reduction credits on behalf of a government or NGO. As of 2013, payments were overwhelmingly initiated by public good payers like governments and NGOs. Where water quality is impacted by excess nutrients, load source apportionment models can support the proportional and pragmatic management of water resources by identifying the pollution sources. There are two broad approaches to load apportionment modelling, (i) load-orientated approaches which apportion origin based on in-stream monitoring data and (ii) source-orientated approaches where amounts of diffuse, or nonpoint source pollution, emissions are calculated using models typically based on export coefficients from catchments with similar characteristics. For example, the Source Load Apportionment Model (SLAM) takes the latter approach, estimating the relative contribution of sources of nitrogen and phosphorus to surface waters in Irish catchments without in-stream monitoring data by integrating information on point discharges (urban wastewater, industry and septic tank systems), diffuse sources (pasture, arable, forestry, etc.), and catchment data, including hydrogeological characteristics. Nature-based solutions Various nature-based solutions exist to tackle nutrient solution. For instance, farms can create artificial wetlands, which help remove nutrient run-off. These can also have a waterbody included. Farms can also create buffer zones, to capture nutrients in groundwater or run-off. Finally, by vegetating drainage ditches, there is another opportunity for excess nutrients to be captured. == Country examples ==

United States Based on surveys by state environmental agencies, agricultural nonpoint source (NPS) pollution is the largest source of water quality impairments throughout the U.S. NPS pollution is not subject to discharge permits under the federal Clean Water Act (CWA). EPA and states have used grants, partnerships and demonstration projects to create incentives for farmers to adjust their practices and reduce surface runoff. In 1998, the agency published a National Nutrient Strategy with a focus on developing nutrient criteria. Between 2000 and 2010, the EPA published federal-level nutrient criteria for rivers/streams, lakes/reservoirs, estuaries, and wetlands; and related guidance. "Ecoregional" nutrient criteria for 14 ecoregions across the U.S. were included in these publications. While states may directly adopt the EPA-published criteria, the states need to modify the criteria to reflect site-specific conditions in many cases. In 2004, EPA stated its expectations for numeric criteria (as opposed to less-specific narrative criteria) for total nitrogen (TN), total phosphorus (TP), chlorophyll a(chl-a), and clarity, and established "mutually-agreed upon plans" for state criteria development. In 2007, the agency stated that progress among the states on developing nutrient criteria had been uneven. EPA reiterated its expectations for numeric criteria and promised support for state efforts to develop their criteria. After the EPA had introduced watershed-based NPDES permitting in 2007, interest in nutrient removal and achieving regional Total Maximum Daily Load (TMDL) limitations led to the development of nutrient trading schemes. In 2008, the EPA published a progress report on state efforts to develop nutrient standards. Most states had not developed numeric nutrient criteria for rivers and streams; lakes and reservoirs; wetlands and estuaries (for those states with estuaries). In the same year, EPA also established a Nutrient Innovations Task Group (NITG), composed of state and EPA experts, to monitor and evaluate the progress of reducing nutrient pollution. In 2009 the NTIG issued a report, "An Urgent Call to Action", expressing concern that water quality continued to deteriorate nationwide due to increasing nutrient pollution, and recommending more vigorous development of nutrient standards by the states. In 2011 EPA reiterated the need for states to fully develop their nutrient standards, noting that drinking water violations for nitrates had doubled in eight years, that half of all streams nationwide had medium to high levels of nitrogen and phosphorus, and harmful algal blooms were increasing. The agency set out a framework for states to develop priorities and watershed-level goals for reductions of nutrients. Discharge permits Many point source dischargers in the U.S., while not necessarily the largest sources of nutrients in their respective watersheds, are required to comply with nutrient effluent limitations in their permits, which are issued through the National Pollutant Discharge Elimination System (NPDES), under the CWA. Some large municipal sewage treatment plants, such as the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C. have installed biological nutrient removal (BNR) systems to comply with regulatory requirements. Other municipalities have made adjustments to the operational practices of their existing secondary treatment systems to control nutrients. NPDES permits also regulate discharges from large livestock facilities (CAFO). Surface runoff from farm fields, the principal source of nutrients in many watersheds, is classified as NPS pollution and is not regulated by NPDES permits. Specifically, Section 303 of the Act requires each state to generate a TMDL report for each body of water impaired by pollutants. TMDL reports identify pollutant levels and strategies to accomplish pollutant reduction goals. EPA has described TMDLs as establishing a "pollutant budget" with allocations to each pollutant source. For many coastal water bodies, the main pollutant issue is excess nutrients, also termed nutrient over-enrichment. A TMDL can prescribe the minimum level of dissolved oxygen (DO) available in a body of water, which is directly related to nutrient levels. (See Aquatic Hypoxia.) TMDLs addressing nutrient pollution are a major component of the U.S. National Nutrient Strategy. TMDLs identify all point source and nonpoint source pollutants within a watershed. Wasteload allocations are incorporated into their NPDES permits to implement TMDLs with point sources. NPS discharges are generally in a voluntary compliance scenario. In Long Island Sound, the TMDL development process enabled the Connecticut Department of Energy and Environmental Protection and the New York State Department of Environmental Conservation to incorporate a 58.5 percent nitrogen reduction target into a regulatory and legal framework. Urbanization and agriculture have contributed to nutrient pollution most notably, the practice of discharging of manure where animal manure is treated as waste and is discharged into water. ==See also==