Project title: Investigation of Sources of Nutrients and Bacteria in Water from Selected Wells near Confined Animal Feeding Operations in Oklahoma

Figure 1. Location of swine CAFO's in Oklahoma (Oklahoma Department of Agriculture, 2001)

Leader: Mark Becker Cooperator: Oklahoma Department of Agriculture Products: A USGS Water-Resources Investigation Report Begin Date: April 2001 End Date: May 2002

Objective:

Background and Problem

Seventy-nine of 790 monitoring wells near about 120 Confined Animal Feeding Operations (CAFO's) for swine sampled by the Oklahoma Department of Agriculture have elevated concentrations of nitrate (oral commun. Dan Parrish, Oklahoma Department of Agriculture, 2001). Nitrate (NO₃^-) is derived from the natural breakdown of fertilizers, soils, and animal wastes. Nitrate concentrations greater than 3 milligrams per liter in ground water are most commonly associated with agricultural land use (Madison and Brunett, 1984). Drinking water with nitrate concentrations greater than recommended drinking-water limit of 10 milligrams per liter (U.S. Environmental Protection Agency, 1996) can cause "blue-baby" syndrome (methemoglobinemia), a condition that prevents blood from carrying oxygen), and has been tentatively linked to increased rates of stomach cancer, birth defects, miscarriage, leukemia, Non-Hodgkin's lymphoma, reduced body growth and slower reflexes, and increased thyroid size (Dorsch and others, 1984; Forman and others, 1985; Fan and others, 1987; National Research Council, 1985). In addition to causing deleterious health effects on humans and livestock, ground water containing elevated concentrations of nitrate and phosphorus can cause eutrophication of streams and lakes into which ground water discharges. Elevated concentrations of nitrate can also be accompanied by counts of fecal-indicator bacteria, which may indicate the presence of pathogenic bacteria, viruses, and protozoa.

Wastewater lagoons, which hold solid and liquid wastes and washwater prior to application on cropland, may seep to ground water or overflow due to storms or mismanagement. Total nitrogen concentration in a swine wastewater lagoon in Oklahoma has been reported to be about 300 milligrams per liter (written commun., Joseph Downey, 2000), indicating a substantial potential to contribute nitrogen compounds to ground water. Officials with the Oklahoma Department of Agriculture wish to obtain additional data to assist in determining the source of contamination of these wells adjoining CAFO's.

Objectives and Scope

The objective of the proposed project is to determine what the types of sources of nutrients and bacteria may be in water from 79 monitoring wells installed at swine CAFO's in Oklahoma. Constituents to be analyzed in water from the well include: water properties (specific conductance, pH, temperature, dissolved oxygen concentration, and turbidity), major nutrients (orthophosphate-phosphorus, nitrite+nitrate-nitrogen, ammonia+organic-nitrogen, nitrite-nitrogen, and ammonia-nitrogen), nitrogen-isotope ratios in nitrate, trace organic compounds (table 1), and ribotyping of E. coli. bacteria (where available), to determine sources of nitrate and other nutrients and potentially pathogenic microorganisms in water.

Relevance and Benefits

The proposed project would provide the Oklahoma Department of Agriculture with: (1) information about the extent of contamination by nutrients and bacteria in ground water in the vicinity of swine CAFO's, (2) an evaluation of possible sources of nutrient and bacteria contamination in ground water near swine CAFO's, and (3) new information about the occurrence of man-made organic chemicals in ground water near CAFO's.

The proposed monitoring would provide information which would better define a major potential water-quality problem, providing knowledge to water-resource managers, assist in determining effects of land use practices on surface and ground water, in evaluation of the effectiveness of nonpoint source pollution management practices, as described in Hirsch (1999).

Approach

Figure 2. Determinative matrix for sources of contamination.

Sources of nitrate in water may be qualitatively determined from the ratio of the nitrogen isotopes ¹⁴N and ¹⁵N in nitrate molecules relative to the ratio of those isotopes in the atmosphere. Because most synthetic nitrogen fertilizers are derived from atmospheric nitrogen by the Haber-Bosch process, nitrate leached from synthetic fertilizers has a similar isotopic ratio as atmospheric nitrogen (d ¹⁵N=-3 to +2 ppt) (Krietler, 1975). Nitrate leached from soils is typically enriched with ¹⁵N (d ¹⁵N=+2 to +8 ppt) (Krietler, 1975). Nitrate derived from animal wastes has even greater amounts of ¹⁵N(d¹⁵N=+10 to +20 ppt) (Krietler, 1975).

The primary limitation of the use of nitrogen-isotope ratios to determine nitrate sources is that the majority of nitrate in ground water typically ranges from +2 to +8 ppt, which means that results are often indeterminate. For instance an isotopic ratio of +5 could indicate that the nitrate is from soils, or from a mixture of soils, synthetic fertilizers and animal wastes (fig. 2).

To help resolve questions posed by mid-range nitrogen-isotope ratios, analysis of trace organic compounds associated with detergents and food additives such as triclosan and caffeine are useful in determining whether human wastewater is a source of elevated concentrations of nutrients or counts of fecal-indicator bacteria in water (table 1, fig. 2).

Ribotyping of genetic patterns of RNA in E.coli. bacteria may be useful in determining sources of nutrient and bacterial contamination from animal wastes (Werblow, 1997). These techniques have been used for several years to determine sources of outbreaks of food-borne illnesses. This method may be particularly useful in ground water near wastewater sources or in highly permeable karstic aquifers, which have relatively fast flow of ground water. Microbial viability may be limited in aquifers with low permeabilities and slow flow rates, which may limit the usefulness of this method. For instance, if the source of much of the nitrate in a ground-water flow system is a dairy farm in an upland recharge area, bacteria from those farms may not survive transport in ground water to reach a lowland, downgradient sampling well.

Historic land use will be mapped near the wells using the Multi-Resolution Land Characterization (MRLC) coverages developed from Landsat images taken from 1988-1992. These maps will provide land use information for the period prior to installation of most of the CAFO's, assisting in the delineation of possible historic sources of contaminants.

Table 1. Wastewater constituents analyzed by USGS National Water Quality Laboratory schedule 8033.
[compound uses in parentheses]

Procedures

To determine possible sources of elevated nitrate in ground-water quality near swine CAFO's in Oklahoma, 79 existing monitoring wells on CAFO's would be sampled for water characteristics (depth to water (if accessible), specific conductance, pH, temperature, dissolved oxygen concentration, and turbidity), nutrients (USGS-NWQL schedule 25), and counts of fecal coliform and bacteria. Water samples will be collected from many of the wastewater lagoons to culture fecal coliform bacteria for ribotyping. Water characteristics would establish the physical conditions of the water, dissolved oxygen in particular would reveal the likelihood of redox reactions such as denitrification. Nutrient concentrations and bacteria counts would establish the degree of contamination (if any) of the water. Nutrient analyses would be conducted by the National Water-Quality Laboratory of the U.S. Geological Survey in Lakewood, Colorado. Nitrate+nitrite-nitrogen analyses would be conducted by cadmium reduction-diazotization and colorimetry using automated-segmented flow (USGS Watstore code 00631; Fishman and Friedman, 1989), with a reporting limit of 0.047 mg/L. Nitrite-nitrogen analyses would be conducted by automated ion-exchange chromatography (USGS Watstore code 00613 (Fishman and Friedman, 1989), with a reporting limit of 0.006 mg/L. Orthophosphate analyses would be conducted by the phosphomolybdate colorimetry method (USGS Watstore code 00671; Fishman and Friedman, 1989), with a reporting limit of 0.018 mg/L.

Nitrogen-isotope ratio analyses of nitrate also would be conducted to determine if the source of elevated nitrate is fertilizers, animal wastes, or soils/mixed. Nitrogen-isotope ratios will be analyzed at the USGS Isotope Laboratory of the stable isotope laboratory of the Department of Biology at Boston University. Nitrogen-isotope ratios will be analyzed by reduction to dinitrogen gas and analysis by GC/MS.

Ribotyping of RNA in E. coli. bacteria isolates (if such isolates can be obtained) would be done to determine sources of elevated bacteria counts. Bacteria from animal wastes collected in the area would be cultured and ribotyped to compare with those cultured from water samples. RNA ribotyping woud be undertaken at the University of Washington, under the direction of Dr. Mansour Samadpour.

Analyses of organic chemicals and pharmaceuticals at detection limits in the tens of parts per trillion (table 1) would be undertaken to determine if human wastewater is contributing to bacterial and nutrient contamination of water from the well. Trace-organic compound analysis would be conducted at the USGS National Water-Quality Laboratory in Lakewood, CO, using Lab Code 8033.

Land uses within one mile of the CAFO's would be determined from coverages based on Landsat images (MRLC) to determine possible sources of nutrients and bacteria pre-dating the construction of most of the CAFO's.

Quality-Assurance

All aspects of the project would be conducted in accordance with "A Quality-Assurance Plan for District Ground-Water Activities of the U.S. Geological Survey" (Brunett and others, 1997), which addresses methods of collection, processing, analysis, storage, review, and publication of ground-water data. All ground-water-quality samples would be collected according to the guidelines provided in "National Field Manual for the Collection of Water-Quality Data, Book 9".

Nutrient and organic-compound concentrations in ground-water samples would be analyzed using quality-assurance and quality-control practices of the National Water-Quality Laboratory in Arvada, Colorado, which includes routine analyses of replicates, spikes, and blind reference samples. In addition to the standard quality control and quality assurance activities (Pritt and Raese, 1995), 5-6 duplicate nutrient samples, 5-6 field blanks, and 1 source water blank would be analyzed for nutrient concentrations and would be collected and analyzed.

Ribotyping would be conducted using standard microbiological analytical methodology, including comparison of replicate samples, and comparison of strains and ribotyping patterns with those of bacteria cultured from locally-obtained animal wastes.

The results of all analyses would be reviewed upon receipt to determine any questionable results; verification of data would be requested from the appropriate laboratory when necessary. Data would be managed in accordance with the Oklahoma District policy established by the Database Process Action Team, Quality Improvement Council.

Selected References

Bingham, R.H., and Bergman, D.L., 1980, Reconnaissance of the water resources of the Enid Quadrangle north-central Oklahoma: Oklahoma Geological Survey, Hydrologic Atlas 7, 4 sheets.

Brunett, J.O., Barber, N.L., Burns, A.W., Fogelman, R.P., Gillies, D.C., Lidwin, R.A., and Mack, T.J., 1997, A quality-assurance plan of district ground-water activities of the U.S. Geological Survey: U.S. Geological Survey Open-File Report 97-11, 21 p.

Dorsch, M.M., and others, 1984, Congenital malformations and maternal drinking water supply in rural South Australia—A case-control study: American Journal of Epidemiology, v. 119, p. 473-480.

Fan, A.M., Wilhite, C.C., and Book, S.A., 1987, Evaluation of the nitrate drinking water standard with reference to infant methemoglobinemia and potential reproductive toxicity: Regulatory Toxicology and pharmacology, v. 7, p. 135-137.

Farrar, J.W., 1997, Results of the U.S. Geological Survey's Analytical Evaluation Program for Standard Reference Samples: T-147 (Trace Constituents), T-149 (Trace Constituents), M-142 (Major Constituents), N-53 (Nutrient Constituents), N-54 (Nutrient Constituents), P-28 (Low Ionic Strength Constituents), GW-1 (Ground-water Constituents), and Hg-24 (Mercury) Distributed in April 1997: U.S. Geological Survey Open-File Report 97-553, 184 p.

Fishman, M.J., and Friedman, L.C., eds., 1989, Methods for determination of inorganic substances in water and fluvial sediments: U.S. Geological Survey Techniques of Water-Resources Investigations, book 5, chap. A1, 545 p.

Forman, D., Al-Dabbagh, S., and Doll, R., 1985, Nitrates, nitrites, and gastric cancer in Great Britain: Nature, v. 313, p. 620-625.

Hinton, M., 2001, Tests planned for water wells near hog sites: Sunday Oklahoman, v. 110, no. 13, p. 1-A and 5-A.

Hirsch, R.M., 1999, Priority issues for the Federal-State Cooperative Program, fiscal Year 200: U.S. Geological Survey Water-Resources Division Memorandum No. 99.30, 3 p.

Madison, R.J., and Brunett, J.O., 1984, Overview of the occurrence of nitrate in ground water of the United States, in National Water Summary, 1984: U.S. Geological Survey Water Supply Paper 2274., p. 93- 104.

Mueller, D.K., and Helsel, D.R., 1996, Nutrients in the Nation's waters--too much of a good thing?: U.S. Geological Circular 1136, 24 p.

Myers, D.N. and F. D. Wilde, editors, 1997, National Field Manual for the Collection of Water Quality Data: U.S. Geological Survey Techniques of Water-Resources Investigations Book 9.

National Research Council, 1985, The health effects of nitrate, nitrite, and N-nitroso compounds: National Academy Press, Washington, D.C., 723 p.

Parkhurst, D.L., Christenson, S.C., and Schlottmann, J.L., 1989, Ground-water-quality assessment of the Central Oklahoma Aquifer, Oklahoma--Analysis of available water-quality data through 1987: U.S. Geological Survey, Open-File Report 88-728, 80 p.

Pritt, J.W., and Raese, J.W., 1995, Quality assurance/quality control manual--National Water Quality Laboratory: U.S. Geological Survey Open-File Report 94-26, 15 p.

U.S. Environmental Protection Agency, 1996, Drinking water regulations and health advisories, EPA 822- 8-96-002, 11 p.

Werblow, S., 1997, DNA whodunit--microbiologists use genetic fingerprinting to identify sources of pollution: Conservation Technology Information Center, Lafayette, Indiana, CTIC Newsletter, October/November 1997, p. 15-16