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Pouring It On

Nitrate Contamination of Drinking Water

Thursday, February 1, 1996

Pouring It On

Nitrate Contamination of Drinking Water

Nitrate in drinking water at levels greater than the Federal standard of 10 parts per million (ppm) can cause methemoglobinemia, a potentially fatal condition in infants commonly known as blue-baby syndrome. According to Dr. Burton Kross, of the University of Iowa's Center For International Rural and Environmental Health, nitrate poisoning via drinking water contamination "certainly contributes to national infant death rate statistics" (Johnson and Kross 1990). Agriculture is the primary source of nitrate contamination.

An Environmental Working Group review of nearly 200,000 water sampling records found that over two million people -- including approximately 15,000 infants under the age of four months -- drank water from 2,016 water systems that were reported to EPA for violating the nitrate standard at least once between 1986 and 1995 (Table 1). All of these water systems were termed "significant non-compliers" by EPA and 60% were repeat violators. The ten largest water systems that violated the federal nitrate standard between 1986 and1995 were Columbus, OH; Scottsdale and Chandler, AZ; Decatur, IL; Upland, CA; Bloomington, IL; Peoria, AZ; Manteca, CA; Rialto, CA; and Gilbert AZ.

Table 1: 2.1 million people drank water from systems that violated federal nitrate standards at least once since 1985

State Number of Systems
in Violation
Population Affected
Ohio 36 413,441
Arizona 42 400,765
California 112 380,670
Illinois 156 274,332
Pennsylvania 456 154,877
Kansas 103 86,130
Washington 39 67,325
Oklahoma 132 66,938
Iowa 137 52,970
Nebraska 116 44,513
Texas 60 41,685
Colorado 22 39,707
Connecticut 8 21,142
Delaware 85 19,142
Michigan 74 18,435
Maryland 59 15,983
New Jersey 59 10,511
New York 16 10,323
Wisconsin 63 6,015
Florida 36 4,964
Minnesota 44 4,440
Indiana 35 3,798
Kentucky 5 3,428
North Carolina 19 2,720
South Dakota 13 2,619
West Virginia 6 2,303
New Mexico 12 1,938
Virginia 10 1,889
Oregon 8 1,820
Vermont 2 1,680
Idaho 4 1,530
Rhode Island 8 1,240
Montana 8 963
Alaska 7 850
Missouri 4 634
South Carolina 10 395
Maine 5 365
Georgia 1 200
North Dakota 3 155
Massachusetts 1 25
     
Total 2,016 2,162,860

Water utilities in Decatur, Bloomington, Streator, and Pontiac, Illinois all violated the nitrate standard in eight years out of the ten. Danville, Illinois was close behind with seven violations during the same time period. Columbus, Ohio violated the standard five years in a row from 1985 through 1989, at which time they were granted a special "waiver" from subsequent violations. Under this deal with the state, the utility can serve water that exceeds that standard without being cited for violating the standard as long as the community is warned about it (Evans 1995).

An additional 3.8 million people drink water from private wells that are contaminated above the 10 ppm nitrate standard. In seven states -- California, Pennsylvania, New York, Illinois, Wisconsin, Minnesota, and Iowa -- more than 100,000 people are exposed to nitrate above the federal standard via private drinking water wells (Table 2).

 

Table 2: In ten states, more than 10% of all drinking water wells are contaminated with nitrate above federal health standards

 

State Population Above
EPA Standards
% Contamination Above
EPA Standards
Delaware 48,311 35.0%
Kansas 69,944 28.0%
Iowa 124,771 18.3%
California 428,301 15.0%
New York 239,685 15.0%
Nebraska 52,870 14.0%
Arizona 37,612 14.0%
Illinois 164,510 12.0%
Colorado 29,800 12.0%
Wisconsin 148,582 10.0%
Texas 80,404 9.4%
Minnesota 134,365 9.3%
Pennsylvania 245,241 9.0%
Connecticut 55,412 9.0%
Maryland 67,437 8.0%
Maine 43,100 8.0%
New Jersey 61,936 6.8%
South Dakota 9,428 6.7%
Virginia 96,205 6.4%
Wyoming 6,899 6.4%
Missouri 51,330 5.0%
Oregon 27,477 5.0%
North Dakota 7,170 4.6%
Indiana 69,900 4.5%
Kentucky 42,289 4.2%
Idaho 9,536 4.0%
Nevada 3,215 4.0%
Arkansas 22,341 3.9%
Ohio 66,474 3.8%
Montana 7,342 3.8%
North Carolina 59,926 3.2%
Alaska 4,763 3.2%
New Mexico 6,165 2.0%
Utah 1,140 2.0%
Washington 13,533 1.5%
New Hampshire 5,809 1.4%
Vermont 3,213 1.4%
Michigan 20,234 1.2%
Oklahoma 5,762 1.2%
Florida 17,099 1.0%
Georgia 13,141 1.0%
Massachusetts 5,118 1.0%
Tennessee 8,175 0.9%
West Virginia 5,396 0.9%
Louisiana 4,855 0.8%
South Carolina 9,579 0.7%
Mississippi 1,316 0.2%

Over twelve million people in the United States drink water from nearly 1,000 water systems where some or all of the drinking water supply is contaminated by nitrate at levels above the EPA's 10 ppm standard (Table 3); 8.7 million of these people are in California (Table 4). While the majority of these systems are still able to provide drinking water that meets the 10 ppm standard, often this comes at significant cost to water utilities and ratepayers.

Table 3: Drinking water supplies for many U.S. cities are contaminated with nitrate above the federal health standard

 

Rank System City State Population Served Date of most recent sample
over federal nitrate standard
Percent of samples over
federal nitrate standard.
Number of Samples Taken Maximum Test Result
 
1 Phoenix Munic. Water System Phoenix AZ 1,000,000 10/26/94 7.3% 82 17.4
2 El Paso Water Utilities El Paso TX 620,000 5/26/93 2.0% 49 13.47
3 Mesa, Munic. Water Dept. Mesa AZ 302,000 8/10/94 2.4% 41 11
4 Scottsdale Scottsdale AZ 174,170 10/20/94 1.0% 105 10
5 Glendale Munic. Water CC Glendale AZ 150,000 3/1/95 10.5% 57 16
6 Chandler, Munic. Wtr Dept. Chandler AZ 120,000 10/12/94 5.0% 60 13.9
7 Janesville Water Utility Janesville WI 52,133 12/5/94 100.0% 1 11
8 Peoria, City Of Peoria AZ 50,618 10/6/94 13.3% 15 12.6
9 State College Boro. Water Auth. State College PA 47,000 2/18/93 3.2% 31 10.4
10 Newark, City Of Newark OH 46,000 11/10/94 2.8% 36 41
11 Gilbert, Town Of Gilbert AZ 45,000 6/24/94 7.1% 14 19.4
12 Utility Parkway Cedar Falls IA 34,298 4/10/95 1.4% 71 10.6
13 Richland, City Of Richland WA 32,600 6/27/95 19.3% 942 19
14 Friendswood, City Of Friendswood TX 27,108 6/12/95 5.0% 20 30.07
15 AZ Water Co., Casa Grande Casa Grande AZ 26,121 1/11/94 8.3% 24 12.1
16 Pasco Water Department Pasco WA 25,465 8/30/94 33.3% 36 17.4
17 Citizens Util., Mohave Bullhead City AZ 25,000 6/13/95 31.3% 16 15
18 SACWSD - Shallow Well #18 Commerce City CO 22,400 6/7/95 8.5% 59 12.3
19 Avondale, City Public Works Avondale AZ 22,000 6/16/93 22.2% 9 14
20 Kearney, City Of Kearney NE 21,751 7/14/93 25.0% 8 16.4
21 Dodge City, City Of Dodge City KS 21,294 2/8/95 17.8% 45 16.2
22 Bonney Lake Water Department Bonney Lake WA 18,586 5/10/94 14.3% 14 27
23 Great Bend PWS/Central KS Utils Great Bend KS 15,427 3/1/95 7.1% 28 10.41
24 Spanaway Water Company Spanaway WA 14,613 9/22/94 7.7% 26 27
25 Brighton, City Of Brighton CO 14,500 5/25/93 15.4% 26 18.5
26 Ephrata Joint Authority Ephrata PA 14,300 7/14/93 2.9% 35 11
27 Shippensburg Boro. Water Shippensburg PA 13,500 5/20/94 5.3% 19 10.2
28 Horsham Water Authority Horsham PA 13,304 1/26/93 2.3% 44 101.7
29 Beatrice, City Of Beatrice NE 12,891 7/14/94 36.4% 22 252.9
30 Sterling, City Of Sterling CO 12,500 7/11/94 23.5% 34 13.1

 

Table 4: Drinking water supplies for many California cities are contaminated with nitrate above the federal health standard

Rank System City Population Served Date of most recent sample over federal nitrate standard Percent of samples over federal nitrate standard Number of Samples Taken Maximum Test Result
1 Los Angeles Los Angeles 3,600,000 6/15/95 1.1% 190 12.5
2 City Of Santa Ana Santa Ana 293,700 11/22/95 24.0% 146 12.9
3 Eastern MWD San Jacinto 253,705 5/9/95 3.7% 54 12.2
4 City Of Riverside Riverside 245,000 11/30/95 6.6% 457 35.6
5 Glendale-City, Water Dept. Glendale 184,000 11/7/95 5.4% 331 11.9
6 California Water Service Bakersfield 182,670 7/13/95 3.6% 357 13.1
7 City Of Modesto Modesto 180,320 10/7/94 7.7% 260 13.9
8 City Of Pasadena Pasadena 153,217 6/23/93 8.3% 24 12.8
9 San Gabriel Valley Water Co. El Monte 150,105 3/13/95 3.2% 317 12.3
10 City Of Garden Grove Garden Grove 148,000 1/12/93 1.3% 77 14.5
11 City Of Ontario Ontario 143,285 1/25/94 1.1% 179 10.2
12 Pomona- City, Water Dept. Pomona 136,525 12/4/95 38.0% 739 22.5
13 Cucamonga CWD Rancho Cucamonga 128,000 11/22/95 11.3% 160 15.5
14 Desert Water Agency Palm Springs 125,000 1/27/93 1.6% 61 11.8
15 City Of Corona Corona 104,000 8/9/95 50.0% 44 26.7
16 San Gabriel Valley WC Fontana 102,599 11/7/95 9.2% 295 18.3
17 California Water Service Salinas 100,300 9/8/94 5.3% 114 13.3
18 Suburban Water Systems San Jose 93,758 11/15/95 17.9% 563 30.9
19 Daly City MWU Daly City 92,311 10/19/95 50.0% 18 15.1
20 City Of Alhambra Alhambra 86,300 6/8/94 5.7% 35 12.7
21 California Water Service Visalia 82,300 4/8/93 0.5% 182 10.0
22 Cal-Water Service Co. Chico 73,220 12/15/94 2.3% 177 13.6
23 Palmdale WD Palmdale 70,000 2/2/95 4.9% 41 12.3
24 Redlands City MUD Redlands 69,300 5/16/95 4.0% 430 36.0
25 City Of Upland Upland 66,383 5/31/94 1.7% 59 17.5
26 Casitas Municipal WD Oakview 60,000 2/21/95 50.0% 2 12.0
27 California Water Service South San Francisco 56,200 12/29/94 40.0% 25 18.4
28 East Valley WD San Bernardino 55,000 10/12/95 6.3% 573 16.7
29 Calif Water Service Los Altos 53,740 3/21/94 1.3% 80 10.0
30 City Of Chino Chino 52,130 10/26/95 35.3% 85 19.2

Unlike virtually all other contaminant standards, the 10 ppm federal drinking water standard for nitrate contains no safety factor. This means that several days' worth of infant formula mixed with water contaminated with nitrate at levels over 10 ppm can easily cause methemoglobinemia in infants under four months of age. Repeated consumption of this water over a period of days or weeks can cause severe blue baby syndrome, and even death.

320 "water systems to watch" serving 2.8 million people in the 21 states have had at least one nitrate sample between nine and ten parts per million. Infants are at significant risk in these communities because prolonged exposure to nitrate at levels extremely close to the 10 ppm standard typically occurs with no efforts to warn the population or reduce nitrate levels in drinking water (Table 5).

Table 5:  Cities with "Water to Watch." 33 large water systems reported at least one tap water or well water sample contaminated

Rank System City State Population Served Highest Sample Date of Highest Sample Number of Samples Taken % Over Int'l Standard
1 Waterloo Water Works Waterloo IA 66,467 9.9 8/10/94 113 25.7%
2 East Hempfield Water Authority Landisville PA 13,493 9.9 9/15/93 73 58.9%
3 Harford County Dpw Bel Air MD 63,000 9.9 7/26/93 20 10.0%
4 Westminster Westminster MD 22,766 9.9 2/18/93 18 77.8%
5 City Of Wasco Wasco CA 13,774 9.8 2/14/95 7 42.9%
6 Northern Il Wtr Corp-Pontiac Pontiac IL 11,200 9.8 3/26/95 63 50.8%
7 City Of Lancaster Authority Lancaster PA 108,000 9.8 2/8/94 18 38.9%
8 Cal. Water Service Co. - East L.A. San Jose CA 152,970 9.8 7/13/93 21 23.8%
9 Morro Bay City Water Dept Morro Bay CA 15,000 9.8 7/5/95 25 28.0%
10 City Of Manteca Manteca CA 44,500 9.8 3/5/93 24 41.7%
11 City Of Chino Hills Chino Hills CA 49,000 9.8 11/10/93 17 35.3%
12 Chippewa Falls Waterworks Chippewa Falls WI 12,989 9.7 8/30/93 1 100.0%
13 Hillcrest Wc-1,2,3&4 Yuba City CA 10,062 9.6 7/25/95 6 33.3%
14 City Of Fresno Fresno CA 390,350 9.6 8/31/94 312 17.6%
15 Garden City, City Of Garden City KS 24,097 9.5 5/9/94 27 22.2%
16 Ottumwa Water Works Ottumwa IA 24,488 9.5 5/1/95 14 50.0%
17 Lca-Wlsa Central Division Wescosville PA 17,285 9.4 6/21/94 244 95.9%
18 Bucks Co Water And Sewer Auth Warrington PA 16,200 9.4 12/26/93 3 33.3%
19 LaCrosse Waterworks La Crosse WI 51,000 9.4 12/15/93 1 100.0%
20 Decatur Decatur IL 83,885 9.4 6/6/95 134 43.3%
21 Cuc-Suburban Sacramento CA 32,000 9.3 2/16/95 69 14.5%
22 City Of Davis Davis CA 48,250 9.3 7/26/95 116 13.8%
23 City Of Bakersfield Bakersfield CA 57,740 9.3 10/3/94 62 8.1%
24 West San Bernardino Cwd Rialto CA 41,454 9.3 3/6/95 34 50.0%
25 Bloomington Bloomington IL 52,000 9.3 5/30/95 63 41.3%
26 City Of Downey Downey CA 91,000 9.2 2/17/93 53 3.8%
27 Northampton Bucks Co. Mun Auth Richboro PA 30,000 9.2 9/8/94 40 2.5%
28 Metropolitan Water Co Tucson AZ 36,250 9.2 12/23/93 109 6.4%
29 City Of Rialto Rialto CA 48,418 9.1 12/7/93 131 27.5%
30 Oxnard Wd Oxnard CA 146,571 9.1 6/22/95 23 17.4%
31 Del Este Modesto CA 11,851 9.1 5/12/93 8 37.5%
32 Chester Water Authority Chester PA 110,000 9.1 1/21/94 11 45.5%
33 City Of Anaheim Anaheim CA 286,680 9.0 8/9/95 136 22.8%
34 Penn State Univ. University Park PA 37,000 8.9 7/13/94 45 37.8%
35 Il American Wtr Cmpny - Pekin Pekin IL 39,000 8.9 7/19/94 34 11.8%
36 San Jose Water Company San Jose CA 921,000 8.9 5/17/93 264 11.4%
37 City Of Ceres Ceres CA 28,988 8.9 2/2/95 8 50.0%
38 City Of Delano Delano CA 29,944 8.9 8/10/93 47 53.2%
39 US Army Fort Irwin Fort Irwin CA 16,000 8.8 2/14/95 42 26.2%
40 Security W & SD Colorado Springs CO 10,007 8.8 4/3/95 80 93.8%

 

Role of Water Utilities

To their credit, water suppliers with nitrate contamination problems frequently solve problems before they are officially considered to be in violation of EPA standards. In some cases individuals in these communities, including vulnerable infants were likely served water with unsafe concentrations of nitrate, even as water suppliers took aggressive measures to ensure that citizens in these communities could drink water that met EPA standards. Based on published estimates of the cost to fix nitrate problems in California and Iowa (Huber 1992, Anton et al. 1988), we estimate that nationwide, ratepayers spend more than $200 million per year to protect infants from nitrate contaminated water. Polluters, of course, pay none of these costs.

Solutions on the Farm

Farmers will, and must, continue to use nitrogen fertilizer. They do not, however, have to overuse it. Each year, there are 8 billion pounds more nitrogen available in farm fields than can be used by the crops growing on this land (NRC 1993). This excess nitrogen has to go somewhere, and much of it ends up in drinking water supplies (NRC 1989, NRC 1993, Hallberg 1989). Other sources such as sewage treatment plants, septic tanks, and atmospheric deposition pale in comparison to the farm contribution.

By following a few simple guidelines -- accounting for all sources of nitrogen in a field (manure and nitrogen fixing crops), timing applications properly, using nitrogen soil tests, and setting realistic yield goals -- farmers can dramatically reduce nitrogen application rates, while maintaining profits and high yields (NRC 1989; NRC 1993; Hallberg and Keeney, 1993; Hallberg, et al. 1991). In Iowa, farmers have successfully implement such a plan and reduced their use of nitrogen-based fertilizers while maintaining high yields (Hallberg et al 1991, Iowa State University 1993).

In the four years from 1991 through 1994, Iowa farmers used eighteen percent less fertilizer per acre of corn than farmers in other Corn Belt states -- and had a corn yield that matched those same Corn Belt farmers. In fact, statewide, Iowa corn growers achieved record yields in 1992 and 1994.

Recommendations

Congress is rewriting laws that regulate nitrate and other contaminants in drinking water. Amendments to the Safe Drinking Water Act passed by the Senate in November 1995, would make nitrate contamination problems even worse. The new legislation would give states and communities no new powers to prevent polluters from fouling tap water supplies, and would prevent them from taking action until it is too late: when contaminants have already exceeded standards. In the House, many members seem poised to support a weaker Safe Drinking Water Act. A Clean Water Act rewrite that passed the House in 1995 would roll back basic water quality protections.

To protect the tens of thousands of infants exposed to unsafe nitrate contamination in drinking water, we recommend that the EPA and the Congress:

  • Immediately establish a new drinking water standard for nitrate of 5 ppm. This new standard -- which would be comparable to standards already established in Germany and South Africa -- would provide a modest two fold safety factor for the infant population.
  • Adopt tough source water protection provisions when amending the Safe Drinking Water Act and the Clean Water Act, giving water suppliers and public health officials clear authority to stop pollution at its source and avoid the danger and expense caused by nitrate contamination of water supplies.
  • Provide technical and financial assistance to farmers to help them improve the efficiency and consistency of their nutrient use to reduce nitrate contamination of source water.
  • Require states to report cases of methemoglobinemia to the Centers for Disease Control.

We believe Congress and the EPA should take steps to protect against nitrates in drinking water, including:

  • Establishing a more protective standard for nitrate in drinking water,
  • Adopting tough source water protections in the Safe Drinking Water Act and Clean Water Act,
  • Providing technical and financial assistance to farmers to help them reduce nitrate contamination of source water.
Key Issues: