How Much Nitrate Is in Rural America’s Water?

John Collins

The drinking water in Pretty Prairie, Kan., population 672, is unsafe to drink due to excessive levels of nitrate from fertilizer runoff. Pregnant and nursing mothers receive free bottled water.

On July 26, the Envi­ron­men­tal Work­ing Group (EWG) announced the launch of the their Tap Water Data­base: Start­ing today, the vast major­i­ty of Amer­i­cans can learn about every poten­tial­ly harm­ful chem­i­cal in their drink­ing water and what sci­en­tists say are the safe lev­els of those contaminants.”

Unfor­tu­nate­ly for us, there are a lot of poten­tial­ly harm­ful” chem­i­cals to learn about and sci­en­tists don’t always agree on the def­i­n­i­tion of safe.”

As the largest nation­al effort of its kind, EWG’s data­base aggre­gates water qual­i­ty tests from near­ly 50,000 pub­lic water util­i­ties in all 50 states (and the Dis­trict of Colum­bia) going back to 2010. Of the 500 con­t­a­m­i­nants these tests were look­ing for, 267 were detect­ed in our drink­ing water. These include:

  • 93 linked to an increased risk of cancer
  • 78 asso­ci­at­ed with brain and ner­vous sys­tem damage
  • 63 con­nect­ed to devel­op­men­tal harm to chil­dren or fetuses
  • 45 linked to hor­mone disruption
  • 38 that may cause fer­til­i­ty problems

This week, EWG pub­lished Trou­ble in Farm Coun­try—a report based on the database’s find­ings that focus­es specif­i­cal­ly on nitrate con­t­a­m­i­na­tion in rur­al America.

Aside from nat­ur­al process­es, nitrates enter our drink­ing water via runoff from fields treat­ed with indus­tri­al fer­til­iz­er and from fac­to­ry farms. In addi­tion to cre­at­ing tox­ic algae blooms that suf­fo­cate water­ways, drink­ing water with unsafe lev­els of nitrate is known to increase a person’s risk of colon, kid­ney, ovar­i­an and blad­der can­cers. The cost of treat­ing water to remove nitrates is often far more than the most affect­ed com­mu­ni­ties can afford. (Note: Can­cer is expen­sive too.) Craig Cox, the author of the report and EWG’s senior vice pres­i­dent for agri­cul­ture and nat­ur­al resources puts it this way: Rur­al Amer­i­cans are bear­ing the brunt of the health risks and eco­nom­ic costs of unchecked farm pollution.”

Below are some impor­tant take­aways from the report, but first:

The Haber – Bosch process, an arti­fi­cial nitro­gen fix­a­tion process, is the main indus­tri­al pro­ce­dure for the pro­duc­tion of ammo­nia today. It is named after its inven­tors, Ger­man chemists Fritz Haber and Carl Bosch, who devel­oped it in the first half of the 20th cen­tu­ry. (Video: BASF / YouTube)

The nat­ur­al nitro­gen cycle. (Image: Wiki­me­dia)

Trou­ble in farm country

The 672 res­i­dents of Pret­ty Prairie, Kan., are sur­round­ed by crop­land — more than 12,000 acres of win­ter wheat, corn, soy­beans and sorghum with­in a four-mile radius of the Farmer’s Co-op grain ele­va­tor. Each year, those crops are sprayed with hun­dreds of thou­sands of pounds of fer­til­iz­er — the main cause of pol­lu­tion in the town’s tap water, which has one of the nation’s high­est lev­els of a chem­i­cal sus­pect­ed to cause cancer.

The prob­lem is nitrate, a chem­i­cal that comes from com­mer­cial fer­til­iz­er and manure. For more than 20 years, the lev­el of nitrate in Pret­ty Prairie’s tap water has exceed­ed the Envi­ron­men­tal Pro­tec­tion Agency’s legal lim­it. In 2014 and 2015 the lev­el was twice the legal limit.

The lim­it — 10 parts per mil­lion, or ppm — was set in 1962 to pro­tect against blue baby syn­drome, a poten­tial­ly fatal con­di­tion that starves infants of oxy­gen if they ingest too much nitrate. But up-to-date sci­ence indi­cates that’s not the only con­cern, and that the legal lim­it is at least twice too lax. Stud­ies by the Nation­al Can­cer Insti­tute have found that drink­ing water with just 5 ppm of nitrate increas­es the risk of colon, kid­ney, ovar­i­an and blad­der can­cers. In Pret­ty Prairie, par­ents with infants under 6 months old, and nurs­ing or preg­nant women can get free bot­tled water, but that does noth­ing to pro­tect oth­er res­i­dents from can­cers that may not show up for years or decades.

Nitrate pol­lu­tion, which can also come from sep­tic sys­tems, afflicts towns and cities in farm coun­try across the Unit­ed States. And it’s just one of the threats indus­tri­al agri­cul­ture pos­es to tap water:

  • Fer­til­iz­er and manure also con­tain phos­pho­rus, which can trig­ger mas­sive blooms of algae in lakes and oth­er drink­ing water sources. A type of algae called cyanobac­te­ria pro­duce tox­ins that can end up in drink­ing water.
  • When util­i­ties treat water with chlo­rine to remove algae, fecal bac­te­ria and oth­er farm pol­lu­tants, it cre­ates chem­i­cal byprod­ucts called tri­halomethanes, or TTHMs, linked to can­cer and repro­duc­tive harm.
  • Fed­er­al poli­cies do lit­tle to keep farm pol­lu­tion from get­ting into tap water in the first place. The expen­sive treat­ment need­ed to remove these con­t­a­m­i­nants can bank­rupt small rur­al communities.

Pret­ty Prairie is in Reno Coun­ty, where eight oth­er small towns have nitrate lev­els at or above the increased can­cer risk lev­el of 5 ppm. Nation­wide, 97 per­cent of pub­lic drink­ing water sys­tems with nitrate at or above that lev­el serve 25,000 peo­ple or less. Just like Pret­ty Prairie, those 1,683 com­mu­ni­ties are sur­round­ed by mil­lions of acres of crop­land on which nitro­gen-rich fer­til­iz­ers and manure are applied every year. In 2014 and 2015, aver­age nitrate con­t­a­m­i­na­tion in 463 of these com­mu­ni­ties was at or above 7.5 ppm, well above the lev­el of nitrate that Nation­al Can­cer Insti­tute stud­ies say increas­es the risk of can­cer, and 118 had con­t­a­m­i­na­tion at or above the EPA’s legal limit.

Two-thirds of com­mu­ni­ties with nitrate lev­els at or above 5 ppm are in 10 states where agri­cul­ture is big busi­ness. Almost three-fourths of com­mu­ni­ties whose drink­ing water is at or above the legal lim­it are found in just five states — Ari­zona, Cal­i­for­nia, Kansas, Okla­homa and Texas. Even a cur­so­ry look at the map above shows that these com­mu­ni­ties are clus­tered in some of the most heav­i­ly farmed coun­ties in the nation.

The mil­lions of rur­al Amer­i­cans who get drink­ing water from their own wells may be at even greater risk. Between 1991 and 2004, the U.S. Geo­log­i­cal Sur­vey test­ed pri­vate domes­tic wells for nitrate. In areas dom­i­nat­ed by agri­cul­ture, at least 7 per­cent of the wells test­ed exceed­ed the legal lim­it for nitrate. One-fourth of shal­low wells under inten­sive­ly farmed land were con­t­a­m­i­nat­ed above the legal limit.

The cost of remov­ing nitrate can be crippling

Last year, the EPA ordered Pret­ty Prairie to build a new water treat­ment sys­tem to low­er nitrate lev­els. The sys­tem could cost $2.4 mil­lion — well over $3,000 for every per­son in town. Eighty-five per­cent or more of the com­mu­ni­ties with ele­vat­ed lev­els of nitrate have no treat­ment sys­tems in place to remove the con­t­a­m­i­nant. Like Pret­ty Prairie, many have long­stand­ing con­t­a­m­i­na­tion prob­lems, but have balked at the high cost of treatment.

Ion exchange and reverse osmo­sis sys­tems are the most com­mon tech­nolo­gies used to get nitrate out of drink­ing water. Ion exchange sys­tems pass water through a resin to remove nitrate. In a reverse osmo­sis sys­tem, pres­sur­ized water is pushed through a mem­brane that removes nitrate and oth­er con­t­a­m­i­nants. Treat­ment costs will vary for each util­i­ty and con­t­a­m­i­na­tion prob­lem. But a range of costs cit­ed in a 2012 report from the Cen­ter for Water­shed Sci­ences at the Uni­ver­si­ty of Cal­i­for­nia at Davis can be used to make rough esti­mates. A com­mu­ni­ty of just under 5,000 peo­ple could incur annu­al costs rang­ing from $195,000 to $1.1 mil­lion to build and oper­ate an ion exchange sys­tem. A reverse osmo­sis sys­tem would be even more expen­sive, rang­ing from $1.1 mil­lion to $4 mil­lion a year.

Nitrate is just the tip of iceberg

When it rains, the runoff from poor­ly pro­tect­ed farm fields car­ries not only nitro­gen, but phos­pho­rous and organ­ic mat­ter like manure, mud and crop residues into streams. Phos­pho­rous from fer­til­iz­er trig­gers blooms of algae, which mul­ti­ply the amount of organ­ic mat­ter in the stream. This puts water util­i­ties in a bind.

Drink­ing water con­t­a­m­i­nat­ed with fecal bac­te­ria or pathogens makes peo­ple sick and can lead to poten­tial­ly fatal dis­eases such as dysen­tery and cholera. To pro­tect peo­ple in the short term, util­i­ties must dis­in­fect the water with chlo­rine or oth­er chem­i­cals. But those chem­i­cals react with algae and oth­er organ­ic mat­ter in the water to pro­duce oth­er chem­i­cals with long-term health haz­ards — dis­in­fec­tion byprod­ucts called tri­halomethanes, or TTHMs.

Drink­ing tap water con­t­a­m­i­nat­ed with TTHMs increas­es the risk of devel­op­ing blad­der can­cer in humans. In ani­mal stud­ies, TTHMs are also asso­ci­at­ed with liv­er, kid­ney and intesti­nal tumors. Stud­ies sug­gest that TTHMs increase the risk of prob­lems dur­ing preg­nan­cy as well, includ­ing mis­car­riage, car­dio­vas­cu­lar defects, neur­al tube defects and low birth weight. The EPA has set a legal lim­it of 80 ppb for TTHMs in drink­ing water. The lim­it was based on the tech­ni­cal fea­si­bil­i­ty of remov­ing TTHMs from drink­ing water after dis­in­fec­tion and did not con­sid­er their long-term tox­i­c­i­ty. In 2010, Cal­i­for­nia state sci­en­tists esti­mat­ed that expo­sure to 0.8 ppm of TTHMs — 100 times low­er than the fed­er­al legal lim­it — would pose a one-in-a-mil­lion life­time risk of cancer.

Most com­mu­ni­ties with high lev­els of TTHMs in tap water rely on sur­face water sup­plies that are more vul­ner­a­ble to pol­lut­ed runoff from farm fields. The Tap Water Data­base shows that water sup­plies in 1,647 com­mu­ni­ties, serv­ing 4.4 mil­lion peo­ple, are con­t­a­m­i­nat­ed with TTHMs in amounts at least 75 times high­er than California’s one-in-a-mil­lion can­cer risk lev­el. Between 2014 and 2015, 411 of those com­mu­ni­ties had TTHMs at or above the EPA’s legal limit.

As with nitrates, high lev­els of TTHM con­t­a­m­i­na­tion are con­cen­trat­ed in major farm­ing states. About 56 per­cent of com­mu­ni­ties with TTHM lev­els between 60 ppb and the legal lim­it of 80 ppb are in 10 states. Five states — Cal­i­for­nia, Louisiana, Mis­souri, Okla­homa and Texas — cov­er almost two-thirds of com­mu­ni­ties with TTHM con­t­a­m­i­na­tion above the legal lim­it. Three of those states are also in the top 10 nation­wide for high nitrate contamination.

Pre­ven­tion is the key to keep­ing TTHMs and oth­er tox­ic dis­in­fec­tion byprod­ucts out of drink­ing water. Get­ting TTHMs out of drink­ing water once they have formed can be com­pli­cat­ed and expen­sive. Also, dis­in­fec­tion is com­mon­ly the last step in water treat­ment, which makes it even hard­er to remove TTHMs once they have formed. Dif­fer­ent dis­in­fec­tion process­es can decrease TTHM lev­els, yet pro­duce oth­er, sim­i­lar­ly tox­ic byprod­ucts, and even increase the leach­ing of lead from pipes.

Util­i­ties can use enhanced coag­u­la­tion, gran­u­lar acti­vat­ed car­bon or nanofil­tra­tion to remove algae and oth­er sources of organ­ic mat­ter out of the water before it is dis­in­fect­ed. In the Tap Water Data­base, EWG only has data about exist­ing treat­ment sys­tems for a lit­tle more than half of the small com­mu­ni­ties with high lev­els of TTHMs. But of those for which we have infor­ma­tion, only about one in eight have treat­ment sys­tems specif­i­cal­ly for TTHMs and oth­er dis­in­fec­tion byproducts.

Act now before it’s too late

For Pret­ty Prairie and oth­er com­mu­ni­ties with extreme­ly high con­t­a­m­i­na­tion lev­els, it may be too late to stave off the prob­lem. Expen­sive new treat­ment facil­i­ties may be the only option because these water sup­plies are just too pol­lut­ed. But more than 80 per­cent of com­mu­ni­ties with ele­vat­ed nitrate lev­els are still below 75 per­cent of the legal lim­it. Aggres­sive action now to cut pol­lu­tion and clean up the rivers, streams and aquifers that rur­al Amer­i­cans depend on for drink­ing water could pro­tect fam­i­lies and avoid poten­tial­ly crip­pling costs. Sim­ple and famil­iar con­ser­va­tion prac­tices, if applied in the right places, can often improve water qual­i­ty dramatically.

The Iowa Nutri­ent Reduc­tion Strat­e­gy, for exam­ple, iden­ti­fied three con­ser­va­tion prac­tices that are high­ly effec­tive in keep­ing nitrate out of water sup­plies. At the top of the list is keep­ing fields cov­ered with grass­es, or cov­er crops, after the com­mer­cial crop is har­vest­ed. Prac­tices that improve the fer­til­iz­er man­age­ment, and that cut ero­sion and runoff from fields, are also effec­tive ways to reduce nitrate pol­lu­tion and keep TTHMs out of drink­ing water.

States and coun­ties could and should act on their own. But the upcom­ing fed­er­al farm bill is a remark­able oppor­tu­ni­ty to help local com­mu­ni­ties secure clean and safe drink­ing water by keep­ing nitrates and oth­er con­t­a­m­i­nants out of the water in the first place.

The list on the left also includes Bro­mate and N‑nitrosodimethylamine. (Image: ewg​.org)

For more infor­ma­tion about how the 2018 Farm Bill could address water con­t­a­m­i­na­tion, check out the full report. To enter your zip­code into EWG’s Tap Water Data­base, click here.

John Collins is the edi­tor of Rur­al Amer­i­ca In These Times. He lives between Min­neapo­lis and La Pointe, Wis­con­sin, a vil­lage on Made­line Island in Lake Superior.
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