Dairy Feedlot Contributions to Groundwater Contamination - A Preliminary Study in New Mexico.
Editor's note Editor's Note (foaled in 1993 in Kentucky) is an American thoroughbred Stallion racehorse. He was sired by 1992 U.S. Champion 2 YO Colt Forty Niner, who in turn was a son of Champion sire Mr. Prospector and out of the mare, Beware Of The Cat.
Trained by D. :
This paper is the second in a two-part series about the environmental health impact that dairies have on local communities. Part I, published in the July/August 1999 issue of the Journal, focused on health concerns resulting from groundwater contamination, odor, flies, and dust. Part II addresses the specific problem of groundwater contamination from nearby dairy feedlots and wastewater lagoons.
New Mexico New Mexico, state in the SW United States. At its northwestern corner are the so-called Four Corners, where Colorado, New Mexico, Arizona, and Utah meet at right angles; New Mexico is also bordered by Oklahoma (NE), Texas (E, S), and Mexico (S). ranks 12th in the nation in amount of milk produced. Growth of this industry has been phenomenal in the last decade - especially in New Mexico. In 1970, milk production in New Mexico totaled 304 million pounds; by 1995 it had increased to 3,623 million pounds (1).
Concern is growing about contamination from dairy feedlots as an environmental point-source pollutant in groundwater. Large dairy herds concentrate organic waste in a relatively small land area. Wastewater from the dairy milking center, including wastes from the milking parlor and wash pens (urine, manure, feed solids, hoof hoof, horny epidermal casing at the end of the digits of an ungulate (hoofed) mammal. In the even-toed ungulates, such as swine, deer, and cattle, the hoof is cloven; in the odd-toed ungulates, such as the horse and the rhinoceros, it is solid. dirt) and from the milk house (bulk tank rinse water and cleaning detergents) can be a threat both to groundwater and to surface water (2). The water use of a 100-cow free-stall operation can range from 100 to 1,000 gallons per day. Wastewater is typically collected in a settling lagoon until conditions are suitable for land application or until the liquid evaporates. Lagoons usually are lined with clay, concrete, or a synthetic material; in some cases they are unlined. The collection of wastewater in a lagoon provides an opportunity to apply best management practices to address environmental contamination.
Many of southern New Mexico's milking operations are located in an established dairy center, called "the dairy belt," which runs along the Rio Grande Rio Grande, city, Brazil
Rio Grande (rē` grän`dĭ), city (1991 pop. River to the north and south of the City of Las Cruces Las Cruces (läs kr`sĭs), city (1990 pop. 62,126), seat of Dona Ana co., SW N.Mex., on the Rio Grande, in a farm area irrigated by the Elephant Butte system; founded 1848, inc. 1907. in Dona Ana County. The threat of contamination in this dairy belt is significant because the depth to groundwater in the aquifer of the Rio Grande Valley is unusually shallow, ranging from 5 to 25 feet; the alluvial materials are generally permeable and allow relatively rapid movement of contaminants from the surface to the underlying aquifer; and the shallow groundwater serves as a domestic water source (3).
TABLE 1 Summary of Contaminant Concentrations for all Dairies and All Wells Contaminant Mean Value Range Standard (mg/L) (mg/L) (mg/L) Ammonia .44 0.01 to 1.44 0.2(*) Chloride 975 65 to 2,820 250(**) Nitrate 17.8 0.10 to 179 10(***) Total dissolved solids 3,170 672 to 6,944 500(**) Total Kjeldahl nitrogen 1.7 0.07 to 16.8 - * New Mexico Water Quality Standard (6) ** National Secondary Drinking Water Regulation (5) *** National Primary Drinking Water Regulation (5)
Pursuant to Section 3-104 of the New Mexico Water Quality Control Commission (WQCC WQCC Water Quality Control Commission ) Regulations, all dairies in New Mexico are required to apply for and maintain a groundwater discharge Groundwater discharge is the volumetric flow rate of groundwater through an aquifer. Groundwater discharge, Q
Total groundwater discharge, as reported through a specified area, is similarly expressed as:
a management system in which naturally grazing animals are confined to a small area which produces no feed and are fed on stored feeds. See also dry lot.
backgrounding feedlot dairies must collect water samples from each monitoring well on a quarterly basis and submit the samples to an independent laboratory for analysis of nitrate, ammonia, total Kjeldahl nitrogen Total Kjeldahl Nitrogen or TKN is the sum of organic nitrogen; ammonia, NH3 and ammonium, NH4+ in biological wastewater treatment.
TKN is determined in the same manner as organic nitrogen, except that the ammonia is not driven off before the (TKN TKN Total Kjeldahl Nitrogen
TKN Takanini (suburb of Auckland, New Zealand) ), chloride, and total dissolved solids Total dissolved solids (often abbreviated TDS) is an expression for the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or micro-granular (colloidal sol) suspended form. (TDS TDS
total dissolved solids. ).
The purpose of this preliminary study is twofold:
1. to report on the analysis of groundwater samples that have been collected from dairy feedlot monitoring wells in southern New Mexico and
2. to assess the relative impacts herd sizes and lagoon linings have on groundwater contaminant contaminant /con·tam·i·nant/ (kon-tam´in-int) something that causes contamination.
something that causes contamination. levels.
This study analyzed the results of 313 groundwater samples collected from 26 monitoring wells around seven wastewater lagoons on seven dairies located in southern New Mexico over a six-year period. Water samples were analyzed for nitrate, ammonia, TKN, chloride, and TDS. All data in this study were obtained from the Groundwater Quality Bureau, of the New Mexico Environment Department. Water samples from each dairy previously had been submitted to independent laboratories for analysis of ammonia, nitrate, TKN, chloride, and TDS. Each dairy then reported these data to the state of New Mexico to comply with groundwater discharge permitting requirements. Data were extracted from these reports and entered into SPSS A statistical package from SPSS, Inc., Chicago (www.spss.com) that runs on PCs, most mainframes and minis and is used extensively in marketing research. It provides over 50 statistical processes, including regression analysis, correlation and analysis of variance. [R] Version 8.0 for Windows for statistical analysis. Figure 1 indicates the layout of a typical dairy in southern New Mexico, including the relative location of monitoring wells around wastewater lagoons.
As indicated in Table 1, all mean contaminant levels exceeded water quality standards for nitrate, ammonia, chloride, and TDS at all dairies and all wells (5,6). When organic nitrogen and ammonia nitrogen forms are found together, they are measured as Kjeldahl nitrogen. Free ammonia represents the first product of decomposition of organic matter; thus, appreciable concentrations of free ammonia usually indicate "fresh pollution" of sanitary significance. The following values may be of general significance in appraising free ammonia content in groundwater:
* low - 0.015 to 0.03 mg/L,
* moderate - 0.03 to 0.10 rag/L, and
* high - 0.10 mg/L or greater.
In the treatment of drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. , the goal is a concentration less than 0.1 mg/L; however, less than 0.5 mg/L is acceptable (7).
TABLE 2 Mean Contaminant Levels by Type of Lagoon Lining and ANOVA Results Lining Types Nitrate Ammonia TKN Chloride TDS Clay 28.7(*) .49 1.78 1046 3319 Cement 14.7 .58 1.43 916 3119 Synthetic 7.2 .24(*) 2.13(*) 944 3037 F-tests 25.0 8.2 4,405 1.78 1.42 p-values .0000 .0000 .0130 .1710 .2440 * Tukey honestly significant difference (HSD) post hoc significant at alpha = .05
One-way analysis of variance (ANOVA anova
see analysis of variance.
ANOVA Analysis of variance, see there ) was performed for each contaminant by type of lagoon lining. Nitrate levels were significantly higher for clay linings. Ammonia levels were significantly lower for synthetic linings, but TKN was significantly higher for synthetic linings. No significant effect was found for chloride and TDS concentrations (Table 2).
One-way ANOVA was performed for each contaminant by the number of cows at each dairy. Nitrate, ammonia, chloride, and TDS levels varied significantly by feedlot size, with smaller contaminant concentrations usually exhibited at smaller dairy herd sizes. TKN did not vary significantly by dairy herd size (Table 3).
No trends in contaminant concentrations were evident for depth of monitoring well or depth to water. Nitrate was the only groundwater contaminant that exhibited an increasing trend over the sampling period (1992 to 1997), as illustrated in Figure 2. Concentrations of the other contaminants showed no meaningful trends over time, remaining relatively stable. No significant correlation was found among contaminant concentrations, except for chloride and TDS (r = 0.89, p = .000).
Despite significant progress in reducing water pollution, serious water quality problems persist throughout the country (8). Animal feeding operations (AFOs) can pose a number of risks to water quality and public health, mainly because of the amount of animal manure and wastewater they generate (8). Manure and wastewater from animal feeding operations have the potential to contribute pollutants such as nutrients (e.g., nitrogen, phosphorus), sediment, pathogens, heavy metals heavy metals,
n.pl metallic compounds, such as aluminum, arsenic, cadmium, lead, mercury, and nickel. Exposure to these metals has been linked to immune, kidney, and neurotic disorders. , hormones, antibiotics, and ammonia to the environment. Excess nutrients in water can result in or contribute to eutrophication eutrophication (ytrō'fĭkā`shən), aging of a lake by biological enrichment of its water. In a young lake the water is cold and clear, supporting little life. and anoxia Anoxia Definition
Anoxia is a condition characterized by an absence of oxygen supply to an organ or a tissue.
Anoxia results when oxygen is not being delivered to a part of the body. (i.e., low levels of dissolved oxygen); in combination with other circumstances, excess nutrients have been associated with outbreaks of microbes such as Pfiesteria piscicida (8).
Approximately 450,000 agricultural operations nationwide confine animals (9). U.S. Department of Agriculture (USDA USDA,
n.pr See United States Department of Agriculture. ) data indicate that the vast majority of farms with livestock are small. About 85 percent of these farms have fewer than 250 animal units (AUs) (10). An AU is equal to roughly one beef cow; therefore, 1,000 AUs is equal to 1,000 beef cows or an equivalent number of other animals. In 1992, about 6,600 farms had more than 1,000 AUs and were considered to be large operations (8).
The goal of USDA and United States Environmental Protection Agency "EPA" redirects here. For other uses see EPA (disambiguation) and Environmental Protection Agency.
The Environmental Protection Agency (EPA or sometimes USEPA (U.S. EPA EPA eicosapentaenoic acid.
n.pr See acid, eicosapentaenoic.
n. ) is for AFO AFO Ankle-foot orthosis owners and operators to minimize water pollution from confinement facilities by means of land application of manure. To accomplish this goal, a unified strategy has been established as a national performance expectation: All animal feeding operations should develop and implement technically sound and economically feasible comprehensive nutrient management plans (CNMPs) to minimize impacts on water quality and public health (8).
USDA and U.S. EPA agree that the following minimum components should be included in a CNMP CNMP Comprehensive Nutrient Management Plan (USDA)
CNMP Collectif National de Mobilisation en Psychiatrie
CNMP Centro Nordestino de Medicina Popular (Brasil) :
* feed management,
* manure handling and storage,
* diversion of clean water,
* prevention of waste containment leakage,
* provide adequate storage of dry manure,
* manure treatment,
* management of dead animals,
* land application of manure,
* nutrient balance,
* timing and methods of application,
* land management, and
* adequate record keeping (8).
In southern New Mexico, discharge options for milking-center wastewater include sprinkler application and slow surface irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. on neighboring agricultural fields. To maximize nitrogen uptake, the effluent is usually applied to a cropping system that involves both cool and warm season crops. New Mexico regulations limit the amount of nitrogen that may be applied to crops. The maximum is 200 pounds of nitrogen per acre per year or the amount that the crop will take up plus 25 percent, whichever is greater. Forage crops grown year round and harvested regularly may take up more than 200 pounds of nitrogen per acre. Applying milking-center wastes to fields at rates that do not exceed crop needs for nitrogen is least problematic for groundwater contamination from effluent or from solid manure. Phosphorous phos·pho·rous
Of, relating to, or containing phosphorus, especially with a valence of 3 or a valence lower than that of a comparable phosphoric compound. may accumulate to levels that will harm crops, but in New Mexico's typically phosphorous-deficient soils, high phosphorus levels usually are not a problem (2).
TABLE 3 Mean Contaminant Levels by Number of Cows and ANOVA Results Number of Cows Nitrate Ammonia TKN Chloride TDS 1,000 11.2 .46 1.55 598(*) 2,217(*) 1,200 15.2 .73 1.77 1,266 4,097 1,500 7.8 .17(*) 1.98 1,118 3,487 2,100 49.4(*) .52 1.44 1,206 3,837 3,600 25.1 .52 1.51 1,133 3,393 F-tests 32.1 6.7 .93 27.3 35.2 p-values .0000 .0000 .4480 .0000 .0000 * Tukey HSD post-hoc significant at alpha = .05.
New Mexico farmers are working with state agencies to develop guidelines that allow each dairy farmer to submit a single discharge plan. This effort is new, and guidelines are not yet finalized. The single discharge plan must comply with the technical discharge plan requirements of New Mexico Water Quality Control Commission Regulations (WQCC), requirements of the National Pollutant Discharge Elimination System general permit for Concentrated Animal Feeding Operations (CAFO CAFO
see AFO/CAFO. ), the New Mexico Environment Department (NMED NMED New Mexico Environment Department
NMED Nuclear Materials Event Database
NMED National Maritime Event Database ) Policy for Storage and Disposal of Dairy Wastes, and the Water Quality Act (11).
Analysis of data from this study yielded the conclusions listed below. It is important to emphasize that these are preliminary conclusions based on a fairly small study (313 groundwater samples collected from 26 monitoring wells around seven wastewater lagoons on seven dairies over a six-year period).
1. Mean contaminant concentrations exceeded groundwater quality standards for nitrate, ammonia, chloride, and TDS at all dairies and all wells.
2. Mean nitrate levels were significantly the highest for clay-lined lagoons. Mean TKN, chloride, and TDS levels were slightly higher for clay linings than for cement or synthetic linings. These results suggest that among the three types of linings, clay linings are the least effective at reducing groundwater contamination.
3. Mean ammonia levels were significantly the lowest for synthetic linings. Nitrate and TDS levels were slightly lower than for cement and clay lagoon liners. These results suggest that among the three types of linings, synthetic linings are the most effective at reducing groundwater contamination.
4. Nitrate, ammonia, chloride, and TDS levels varied significantly by feedlot size, with smaller contaminant concentrations exhibited for smaller dairy herd sizes. TKN showed no significant variation by dairy herd size.
5. Mean nitrate concentrations increased during the sampling period; all other contaminant concentrations remained relatively stable.
Acknowledgements: The following people reviewed the manuscript and are gratefully acknowledged: Marcy Leavitt, chief, New Mexico Groundwater Quality Bureau; Tim Kelley, assistant professor, Illinois State University ISU is recognized in the prestigious US News rankings as a "National University", that is, a university which grants a variety of doctoral degrees and strongly emphasizes research. ; Kitty Richards, environmental specialist, New Mexico Border Health Office; Clay Chesney, geologist, U.S. EPA, Region 6.
1. Office of the Director/Secretary (1995), New Mexico Agricultural Statistics, Santa Fe, N.M.: U.S. Department of Agriculture.
2. Ruynon, C. (1998), "Farm*A*Syst [Farmstead Assessment System] Fact Sheet #10," <http://www.cahe.nmsu.edu/pubs/farmasyst/>.
3. Environmental Improvement Division (1984), Seepage Rates and Ground Water Quality Impacts from Manure-Lined Dairy Waste Lagoons, Santa Fe, N.M.: New Mexico Ground Water and Hazardous Waste Hazardous waste
Any solid, liquid, or gaseous waste materials that, if improperly managed or disposed of, may pose substantial hazards to human health and the environment. Every industrial country in the world has had problems with managing hazardous wastes. Bureau.
4. New Mexico Water Quality Control Commission Regulations (1996), Santa Fe, N.M.: New Mexico Water Quality Control Commission.
5. U.S. Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and (1998), Current Drinking Water Standards, www.epa.gov/OGWDW/wot/appa.html.
6. U.S. Environmental Protection Agency (1988), State Water Quality Standards Summary: New Mexico, Available from National Technical Information Service, Springfield, Virginia, NTIS NTIS - National Technical Information Service order number PB89-141998.
7. Salvato, J.A. (1992), Environmental Engineering and Sanitation, 4th ed., New York New York, state, United States
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : John-Wiley and Sons, Inc.
8. U.S. Department of Agriculture and U.S. Environmental Protection Agency (1998), Draft Unified National Strategy for Animal Feeding Operations, <http://www.epa.gov/cleanwater/afo/>.
9. Animal Agriculture: Information on Waste Management and Water Quality Issues (June 1995), Washington, D.C.: General Accounting Office.
10. Farm Costs and Returns Survey (1992), Washington, D.C.: U.S. Department of Agriculture
11. Questions and Answers About CAFO Regulations (1997), Santa Fe, N.M.: New Mexico Environment Department.
Corresponding Author: Stephen D. Arnold, Ph.D., New Mexico State University New Mexico State University, at Las Cruces; land-grant and state supported; coeducational; chartered and opened 1889 as a college. It became New Mexico State Univ. of Engineering, Agriculture, and Science in 1958 and adopted its present name in 1960. , Department of Health Science, MSC (1) (MSC.Software Corporation, Santa Ana, CA, www.mscsoftware.com) Founded in 1963 by Richard H. MacNeal and Robert G. Schwendler, MSC is the world's largest provider of mechanical computer aided engineering (MCAE) strategies, simulation software and services. 3HLS (Hue Lightness Saturation) A color space that is closely related to HSB, except that Brightness is called Lightness and is measured from 0 to 1 rather than from 0 to 100%. See HSB. , P.O. Box 30001, Las Cruces, NM 88003-8001. E-mail: <firstname.lastname@example.org>.