How Food Production Impacts Water Quality

by Mindy Selman, via the World Resources Institute

Our water systems are currently being threatened by the crops we grow and food we produce. In many countries, agriculture is the leading source of nutrient pollution in waterways—a situation that’s expected to worsen as the global population increases and the demand for food grows.

So it’s timely that next week’s World Water Week, an annual conference organized by the Stockholm International Water Institute, is focusing on water and food security.

WRI’s water quality team will be in Stockholm next week to discuss this very topic at a side event entitled, “Securing Water Quality While Providing Food Security: The Nutrient Question,” an event co-organized by Water Environment Federation and Environmental Defense Fund. This session, which takes place on August 29th, will build on the work WRI’s water quality team has done with its partner, Dr. Bob Diaz at the Virginia Institute of Marine Science, to evaluate the scale and scope of global nutrient-related water quality challenges, including how these issues are driven by agriculture.

Eutrophication: A Growing Problem

Nutrient pollution in water, or eutrophication, is a problem that’s grown exponentially in the past 50 years. While nutrients like nitrogen and phosphorus are needed to grow food and maintain healthy ecosystems, too many of these substances can cause havoc in freshwater and coastal ecosystems. Fertilizers and manure from agricultural fields, as well as sewage and runoff from our urban centers are increasingly making their way into waterways, polluting these bodies of water with excessive amounts of nutrients.

Too many nutrients in the water can fuel large algae blooms, including toxic algae. This algae can smother the coral reefs and sea grasses that provide valuable habitat for aquatic species, result in fish kills, and shift the structure of aquatic ecosystems. Plus, when algae blooms die, they suck oxygen out of the water. Under the right conditions, these die-offs create hypoxic areas or dead zones, areas where fish and other aquatic creatures cannot survive. Globally, eutrophication of coastal systems has risen from fewer than 75 systems in 1960 to more than 800 systems today. Of these, more than 500 have experienced hypoxia.

In many nations–including the U.S.–agriculture is the largest source of nutrients to our aquatic systems. Beginning in the early 20th century, people perfected a process for converting non-reactive forms of nitrogen into reactive forms that can be used as fertilizers. This spurred the Green Revolution, leading to a boom of fertilizer use and greatly increased crop yields.

But agricultural intensification had many unintended environmental consequences. Over the past 100 years, human activities have tripled the levels of phosphorus and doubled the levels of reactive nitrogen in the environment compared to natural levels. However, much of the nitrogen and phosphorus used to grow crops washes into rivers and streams during rainstorms or gets released into the atmosphere. Only 20 percent of the nitrogen used in agricultural production is actually consumed as food–the rest is lost to the environment, eventually making its way into our lakes, rivers and estuaries.

Eutrophication’s Financial Impacts

Eutrophication’s impacts have been felt financially as well. Symptoms of eutrophication—like algae blooms and fish kills—oftentimes result in economic losses to tourism and recreation industries, capture fisheries, and aquaculture operations. In 2009 for example, a massive toxic algae bloom off the coast of Maine led to the closure of commercial shellfish beds, crippling a $50 million industry and prompting the state to request disaster relief funds.

Eutrophication can also increase water treatment costs—or in some cases, render freshwater sources unfit to drink. A recent study by the Environmental Working Group estimated that the United States spends $4.8 billion annually to treat drinking water contaminated by too much nitrogen, while additional treatment for drinking water affected by nutrient-fueled toxic cyanobacterial blooms was estimated to cost between $12 million and $66 million for a town of 100,000 people.

Feeding a Growing Population Without Killing Water Systems

As the global population marches towards 9 billion in 2050, we must consider how feeding those people will impact water quality. Producing food for a greater number of people will likely lead to increases in fertilizer use—the Millennium Ecosystem Assessment predicts that human-created nitrogen inputs will rise by nearly another 50 percent by 2050. In addition, there is a risk that natural landscapes like forests and wetlands, which naturally trap and filter nutrients and prevent them from flowing into waterways, will increasingly be converted to agricultural uses as food demands rise. In order to protect and maintain our water resources for future generations, it will be important to focus on developing sustainable agricultural policies that can help achieve food security without compromising our water quality.

Mindy Selman is a senior associate in the People and Ecosystems Program of the World Resources Institute. She leads WRI’s Eutrophication and Hypoxia project, which focuses on nutrient pollution in coastal waters. This piece was originally published at WRI Insights and was reprinted with permission.

11 Responses to How Food Production Impacts Water Quality

  1. BillD says:

    As someone who studies lake food chains, I can say that this is a very good overview of a big problem for lakes, rivers and coastal waters. Farmers are often paid for not farming ‘conservation areas” which are often fields that are especially vulnerable to runnoff and erosion. Congress is exacerbating the problem by eliminating money for conservation areas.

  2. SecularAnimist says:

    It is amazing that someone could write such are article without a SINGLE MENTION of the enormous impact on water quality from meat production.

    According to the UN Food & Agriculture Organization:

    “Livestock production also impacts heavily the world’s water supply, accounting for more than 8 percent of global human water use, mainly for the irrigation of feed crops. Evidence suggests it is the largest sectoral source of water pollutants, principally animal wastes, antibiotics, hormones, chemicals from tanneries, fertilizers and pesticides used for feed crops, and sediments from eroded pastures. While global figures are unavailable, it is estimated that in the USA livestock and feed crop agriculture are responsible for 37 percent of pesticide use, 50 percent of antibiotic use, and a third of the nitrogen and phosphorus loads in freshwater resources. The sector also generates almost two-thirds of anthropogenic ammonia, which contributes significantly to acid rain and acidification of ecosystems.”

  3. Merrelyn Emery says:

    Here we see another aspect of our destruction of the planetary system, again exemplifying our utter disrespect for the laws of nature. So with our mechanistic, linear thinking which results in reductionist science and solutions, we solve the last problem, e.g. feed more people, by creating many more problems, e.g. synthetic fertilizer, eutrophication. At this stage, Selman’s last sentence is pie in the sky and the thought that we will feed 9 billion people or even get to that number is a pure fantasy, ME

  4. Mulga Mumblebrain says:

    Precisely. There are two types of ecological denialism. The rabid Rightwing (if you’ll pardon the tautology)type, that simply refutes every catastrophe if acting to prevent it threatens profit-making, and the Panglossian ‘Centrist’ version, that outlines some horror, then with practised Pollyanaism, pretends that everything will be hunky-dory when we ‘do the right thing’. The fact that we have almost never ‘done the right thing’ on our history, and that the Right will fight it tooth and nail, is happily forgotten. In a way I find this latter denialism even more pernicious, it pretending that things are still basically alright, and a little tweaking will see us through. The truth, that we are careering towards oblivion, and only centuries of dedicated struggle and single-minded effort, and much sacrifice, can save our civilization, is, apparently thought to be too confronting, too threatening to be politically appealing to the masses, struggling as they are under the system’s other hammer blows of austerity, falling standards of living, precarious work conditions etc. When the reality finally hits home, it will be way too late for anything but a vicious struggle for survival.

  5. Rabid Doomsayer says:

    Not only is the runoff from agriculture extremely damaging for the natural environment, it is also a huge waste of resources.

    There have been promising developments, but they have been small scale and not copied.

    Look at the small farmers who recycle everything. What is waste in industrial agriculture, is valued inputs for the small farmer.

  6. Peter Maier says:

    Food production does impact water quality, but so does the sewage after eating the food. Sadly when EPA implemented the Clean Water Act, by using an essential water pollution test incorrectly,it ignored 60% of the pollution in sewage Congress intended to treat under the Act. Among the waste ignored was and still is all the nitrogenous (urine and protein) waste, while this waste, besides exerting an oxygen demand (like fecal waste) also is a fertilizer for alga, thus contributes to excess alga growth, causing eutrophication often resulting in dead zones, red tided and the destruction of coral reefs, i.e. the same type of water quality deterioration caused by the described production of food. Sadly EPA refuses to correct this essential test, while EPA already in 1978 officially acknowledged that not only much better sewage treatment, including nitrogenous waste, was available, but that such facilities actually could be build and operated at much lower cost than conventional sewage treatment plants. The latest attempt to correct this is a petition asking members of Congress to force EPA to correct this test and finally, after 40 years, implement the CWA as was intended. To read the petition click on

  7. Greatgrandma Kat says:

    Hear! Hear! without big profit as the only goal that is exactly right. Nothing goes to waste or is wasted on a small farm. They are small ecosystems run on the value of nature.

  8. Leif says:

    I dropped this on an earlier post but it is relevant here as well.
    “A modest proposal: The Fossil industry should finance a no interest loan to all farmers, with suitable resources, the ability to build out wind and solar PV energy and other green energy sources as a backup cash stream. In addition the Nation should make Medicare health coverage coverage available to all green energy workers to help lower the costs to companies and consumers attempting to compete with the heavily subsidized ecocide fossil industry. A cash cow on every farm could [help] allow each farmer the ability to steward their land in a sustainable manor.”

    Farms would have access to green energy to help lower production costs of fuel and fertilizer. They would not be pressured to exploit every available square inch for production. Perhaps have room for buffer zones. Afford help for labor intensive transition help.

  9. Lionel A says:

    As the global population marches towards 9 billion in 2050

    Don’t think so, more like bottle-necks down to 2 billion or less if BAU isn’t dumped faster than a typhoon’s rain.

    Do they not realise that the Arctic is telling us we are deep in ‘The Lagoons of Pig Faeces‘, echoing Al Franken in ‘Lies (and the Lying Liars Who Tell Them)‘.

  10. Carol says:

    Mulga and others,

    Would you say the state of the earth (health wise) is similar to stage 4 cancer?

    If yes, than human induced ecological collapse is imminent and we humans are on our way out. Our life support system is dying and obviously we will go down with its demise.

    So, what is the healthiest response at this point?

    There will be people that deny until the end (such as those you vividly describe above), some that will fight to the end and sadly, some that will fall into immobilizing depression.

    Clearly for people who are cognizant of the crisis upon us, for those who love the planet and its inhabitants, for those that have children, grandchildren . . . there is overwhelming grief over what humans have done to the earth and to ourselves.

    We are entering a new realm of grief here. The traditional “stages of grief” don’t apply because they end with acceptance ——- and some with “hope and moving on”.

    Moving through grief is usually accompanied by a sense of renewal. If our planet is dying, how can we find renewal and a sense of “moving on”?

    What to do with the foreboding statement: When the reality finally hits home, it will be way too late for anything but a vicious struggle for survival.

    A story:

    I —-and others—–fought for years to try and protect a watershed that, within its boundaries, contained some of the rarest woodlands, prairies and wetlands remaining in the Midwest.
    Through local government regulations, pressure on neighbors, endless meetings,educational tours and more—- we managed to “save” thousands of acres from development. We then embarked on a massive endeavor called “restoration ecology”.
    In essence trying to restore the remaining prairies, woodlands, wetlands in the watershed to pre-settlement conditions.

    With the removal of invasive species, prescribed burns, re-seeding —- the results were spectacular! Rare species of orchids returned to wetlands, diversity of all flora and fauna skyrocketed in the prairies and woodlands.

    Now —–15 years later—– in spite of the temporary recovery of the ecosystems, the notion of “restoration ecology” seems absurd. Due to AGW (in conjunction with habitat destruction, depletion and pollution of groundwater) I realize the “pre-settlement” beauty and diversity that existed can never return as it was.

    A wise biologist/author (elder, if you will) came to visit one of the most spectacular sites in the watershed many years ago. At the time I was young, brimming with hope and felt I could really make a difference in the world (embodying the phrase, “think globally, act locally)!
    The biologist marveled over the existence of this rare wetland that was virtually the same as it was when hunter gatherers lived there thousands of years ago. At the end of his visit his suggestion to me was baffling and infuriating: he told me to “keep journals describing all that lived there, to take pictures and compile as much as I could as a keepsake of what existed so that those in the future could see it”.

    At the time, I thought he was either a bit senile or, at a minimum way too pessimistic. Here we were, working literally day and night to “save” this land . . . this watershed . . . from the ravages of humans and all he had to say was; “take lots of pictures and write about what you see before it’s gone”.

    I was devastated —— clearly in denial at the time. So I shrugged it off and carried on. I did keep journals and took pictures because it was fun to do so!

    Fast forward 2012: turns out, he was right to react as he did. He was, at the time, more aware of climate change than I AND he had many more years of experience dealing with human behavior.

    So . . . I have the journals and thousands of slides/pictures as proof that these prairies, woodlands, wetlands exist. In boxes, they are devoid of the sensorial delights that these places bring to the human brain/soul/spirit along with the fact that they are necessary components to the web of life. But . . . will anyone care . . . and more pressingly, will anyone be here to notice when the wetlands have dried up?

    As I look out the window while I write, the wetlands are ailing due to drought/invasive species and the oaks/hickories/hazelnuts are dying.
    When one is in the field doing environmental work, it truly feels like hospice care.

  11. Gail says:

    Carol I would love to talk to you about your wetlands offline if you have time? witsendnj at yahoo