There is strong evidence that nutrient pollution leading to eutrophication eutrophication is the largest water pollution problem worldwide.[1-3]
Smith, V. & Schindler, D. W. (2009). Eutrophication science: where do we go from here? Trends in Ecology & Evolution (Amsterdam), 24(4), 201–207, p. 201. [“Cultural eutrophication (excessive plant growth resulting from nutrient enrichment by human activity) is the primary problem facing most surface waters today.”]
Eutrophication: Causes, Consequences and Control Volume 2 (Ansari & S. S. Gill, Eds.; 1st ed. 2014). Springer Netherlands. [“On the hydrological map of the world eutrophication has become the primary water quality issue.” p. 1.1]
Kleinman, P.J.A., et al., (2020). “Managing Animal Manure to Minimize Phosphorus Losses from Land to Water” In Animal Manure (eds H.M. Waldrip, P.H. Pagliari and Z. He), p. 201. https://acsess.onlinelibrary.wiley.com/doi/abs/10.2134/asaspecpub67.c12 [“Eutrophication is the most pervasive concern to freshwater and estuarine water bodies worldwide, with phosphorus (P) pollution continuing to expand the extent of eutrophication, its impacts on aquatic life and its disruption of the benefits of ecosystems to humankind.”]
Yes. In a widely cited model, nine planetary boundaries have been identified, including proposed limits for nitrogen and phosphorus discharge. [1-4]
According to the latest update of the planetary boundaries framework, “six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity.”[5] Nutrient pollution boundaries are the most definitively transgressed due to excessive nitrogen and phosphorus discharges into the environment.[6] Some scientists are pleading for a full reckoning of the damages, saying, “Many are aware of nitrogen as one of the most transgressed ‘planetary boundaries’. What is less widely understood is that nitrogen also affects the exceedance of all of the other planetary boundaries.”[7] Current usage of both nitrogen and phosphorus is estimated at about 2 to 3 times the proposed global limits.[8]
Global agriculture’s role in this transgression is estimated at ~80-90%.[9,10] The U.S. is one of a handful of regions in which nitrogen and phosphorus overuse is concentrated.[11]
Rockström, J., et al., (2009). A safe operating space for humanity. Nature (London), 461(7263), 472–475. [Note: This is the first of 3 reports assessing the status of the planetary boundaries. The reports were published in 2009, 2015, and 2023, along with a 2024 overview. The other assessed boundaries are for climate, ozone, ocean acidification, biodiversity, land use, freshwater, novel entities, and aerosols.]
Steffen, W., et al., (2015). Planetary boundaries: Guiding human development on a changing planet. Science, 347(6223), 1259855.
Richardson, K., et al., (2023). Earth beyond six of nine planetary boundaries. Science advances, 9(37), eadh2458.
Rockström, J., et al., (2024). Planetary Boundaries guide humanity’s future on Earth. Nature Reviews Earth & Environment, 5(11), 773-788.
Richardson, K., et al., (2023). Abstract.
Richardson, K., et al., (2023), p. 4, figure 1. [Showing N and P deep into the “high risk zone.”]
Sutton, M. A., et al., (2021). The nitrogen decade: mobilizing global action on nitrogen to 2030 and beyond. One Earth, 4(1), 10-14. p. 10. [“By massively increasing the supply of nitrogen compounds, humans are worsening air and water quality, contributing to climate change and stratospheric ozone depletion, and thereby threatening health, biodiversity, and livelihoods.”]
Richardson, K., et al., (2023), p. 5, Table 1. [The P boundary set at 11 Tg with current use at 22.6 Tg. The N boundary at 62 Tg, with current use at 190 Tg. ]
Sutton, M. A., et al., (2021), Figure 1, p. 11.
Campbell, B., et al., (2017). Agriculture production as a major driver of the Earth system exceeding planetary boundaries. Ecology and Society, 22(4), 8, p. 4. [“We estimate agriculture’s role in the PB (transgression of planetary boundary) as being greater than 90%.”]
Steffen, W., et al., (2015), Figure 2, p. 3.
Briefly, the major impacts are[1]:
Diminished water quality of fresh waterways, groundwater, coastal waters, and oceans. Scarcity of clean drinking water and negative health impacts of impure water. Unhealthful air quality due to ammonia, particulate matter, and ozone. Biodiversity loss and ecosystem degradation. Greenhouse gas emissions. Impaired soil quality. Potential food insecurity from phosphorus overuse leading to global or regional shortages or price spikes.[2,3]
Sutton, M. A., et al., (2013). Our nutrient world. The challenge to produce more food & energy with less pollution. Centre for Ecology & Hydrology. [Experienced researchers present a good overview of the global environmental impacts of nutrient pollution. See, pp. 32-51]
W.J. Brownlie, et al., (eds.) (2022) Our Phosphorus Future. Towards global phosphorus sustainability. UK Centre for Ecology & Hydrology, Edinburgh, doi: 10.13140/RG.2.2.17834.08645, p. 24. [“Five countries hold around 85% of known phosphate rock reserves, with 70% found in Morocco and Western Sahara alone. Most countries do not have any phosphate rock reserves and are reliant on imports to supply their phosphorus demands to maintain food security. China, Morocco and Western Sahara, the USA and Russia currently produce around 80% of the planet’s phosphate rock supply.” at p. 22]
Brownlie, W. J., et al., (2023). Phosphorus price spikes: A wake-up call for phosphorus resilience. Frontiers in Sustainable Food Systems, 7, 1088776, Abstract. [“Phosphorus vulnerability can be described as the degree to which people/systems are susceptible to harm due to the physical, geopolitical and socio-economic dimensions of global phosphorus scarcity and pollution.”]
Yes, almost certainly. Nutrient pollution is acknowledged by the EPA as “the most widespread stressor” in the nation’s lakes, rivers and streams.[1-3]
The agency has further stated that, “The finding that nutrient pollution is the leading cause of use impairment in U.S. waters is supported by data from states’ water quality assessment reports, National Aquatic Resources Surveys, and associated reports to Congress…”[4] And it has specifically acknowledged high nutrient levels as “the leading problem” for the nation’s lakes.[5]
More broadly, the EPA calls nutrient pollution “one of America’s most widespread, costly and challenging environmental problems,”[6] and “a continuing and growing challenge with profound implications for public health, water quality, and the economy.”[7]
U.S. EPA (2024) National Lakes Assessment: [For lakes, “Nutrient pollution was the most widespread stressor measured.”]
U.S. EPA (2023) National Rivers and Streams Assessment: The Third Collaborative Survey. EPA 841-R-22-004. [For rivers and streams, “Nutrients (phosphorus and nitrogen) were the most widespread stressors.”]
U.S. EPA (2021) National Coastal Condition Assessment: A Collaborative Survey of the Nation’s Estuaries and Great Lakes Nearshore Waters, EPA 841-R-21-001, p. 53. [For Great Lakes near-shore areas, “Similar to findings from other assessments, the NCCA found that elevated nutrient levels are widespread stressors.”]
U.S. EPA (2015) A Compilation of Cost Data Associated with the Impacts and Control of Nutrient Control of Nutrient Pollution, EPA 820-F-15-096, see, Introduction, p. I.1.
U.S. EPA (2017) National Water Quality Inventory: Report to Congress, EPA 841-R-16-011, p. 10.
U.S. EPA (2024) Nutrient Pollution, The Problem. https://www.epa.gov/nutrientpollution/problem (Accessed 2/6/25)
Radhika Fox (EPA Assistant Administrator) to State Environmental Secretaries, Commissioners, and Directors State Agriculture Secretaries, Commissioners, and Directors Tribal Environmental and Natural Resource Director (April 5, 2022) Memorandum: Accelerating Nutrient Pollution Reductions in the Nation’s Waters, Washington, D.C., p. 1. https://www.epa.gov/system/files/documents/2022-04/accelerating-nutrient-reductions-4-2022.pdf
Nutrient pollution contributes to:[1] The degradation of rivers, lakes, wetlands, and coastal zones.[2] Algae blooms, oxygen depletion, invasive species.[3] Coastal dead zones and deoxygenation of the oceans.[4] Loss of biodiversity, extinctions, shrinking populations.[5] Clean-water scarcity for humans, plants, and animals.[6] Human health impacts via toxins and nitrates.[7] Greenhouse gas emissions.[8] Air pollution, PM2.5, and the nitrogen cascade.[9] Loss of use for recreation, swimming, and enjoyment of nature.[10]
Note: Each of these subjects is covered or will be covered at length in various pages on the site or in the following pages in this category. We offer a single reference for each with the understanding that they are all important, complex, and interconnected. None of these points are controversial.
U.S. EPA (2024). National Water Quality Inventory: Report to Congress, EPA 841-R-16-011, Figure 1, p. 4.
Munn, M.D., et al., 2018, Understanding the influence of nutrients on stream ecosystems in agricultural landscapes: U.S. Geological Survey Circular 1437, 80, p. 17. [“A major problem associated with excessive nutrient concentrations in streams is eutrophication, which occurs when excessive nutrients stimulate the growth of aquatic vegetation. Excessive vegetation can result in the depletion in dissolved oxygen, which can have a detrimental influence on aquatic biota.”]
Diaz, R. J., & Rosenberg, R. (2008). Spreading Dead Zones and Consequences for Marine Ecosystems. Science (American Association for the Advancement of Science), 321(5891), 926–929, p. 928. [“In the northern Gulf of Mexico, the occurrence and extent of the dead zone are tightly coupled with freshwater discharge from the Mississippi River, which delivers large quantities of nutrients from U.S. agricultural activities.”]
U.S. EPA (2023). National Rivers and Streams Assessment: The Third Collaborative Survey. EPA 841-R-22-004. [“Poor biological condition was more likely when rivers and streams were in poor condition for nutrients.”]
Wang, M., et al., (2024). A triple increase in global river basins with water scarcity due to future pollution. Nature Communications, 15(1), 880–880, p. 2. [“We find that current and future water scarcity becomes a substantially more severe issue globally when implementing our clean-water scarcity assessment… Due to their high nitrogen pollution levels, many sub-basins in South China, Central Europe, North America, and Africa become water scarcity hotspots.”]
Ward, M. H., et al., (2018). Drinking water nitrate and human health: an updated review. International journal of environmental research and public health, 15(7), 1557, p. 20. [“Populations with the highest exposure to nitrate from their drinking water are those living in agricultural regions, especially those drinking water from shallow wells near nitrogen sources (e.g., crop fields, animal feeding operations).”]
U.S. EPA (2024) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022, EPA 430-D-24-004, Figure 5-4, p. 5-29 [“Sources and Pathways of Nitrogen that Result in N2O Emissions from Agricultural Soil Management”]
Wyer, K. E., et al., (2022). Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health. Journal of Environmental Management, 323, 116285–116285, p. 7. [“There is currently a chain that exists between NH3 emissions, the formation of PM2.5, and the subsequent impacts that this PM2.5 has on human health.”]
Environmental Integrity Project (EIP) (2022) The Clean Water Act at 50: Promises Half Kept at the Half-Century Mark, Table 1, p. 4. [Based on state water quality assessments, “about half of the river and stream miles and lake acres that have been studied across the U.S. are so polluted they are classified as “impaired.” That means they are too polluted to meet standards for swimming and recreation, aquatic life, fish consumption, or as drinking water sources.”]