Ground Water Bacterial Investigation for Milford Valley
In the fall of 1998, DEQ and the Southwest Public Health Department began receiving complaints from residents of the Milford Flats area that bacteria were present in private drinking water wells. Milford Flats is located south of the town of Milford in Beaver County. In response to these complaints, DEQ formed a Ground Water Steering Committee comprised of federal, state, and local agencies, and Milford Flat residents. The objective of the Ground Water Steering Committee was to determine the extent of contamination and other factors concerning ground water in the Milford Flats area.
In December 1998 and January and February 1999, water samples were collected from the following: 25 private wells; the Beaver River and associated canals; Circle Four Farms swine wastewater lagoons; Circle Four Farms shallow monitoring wells; and Circle Four Farms deep water supply wells. Six different analytical approaches were conducted for the water samples. The first analysis identified coliform bacteria isolates from 20 of the 25 private water wells. After wellhead decontamination by sodium hypochlorite, a second analysis was conducted for the 20 private wells that tested positive for bacteria in the first round of sampling. A third analysis was to perform molecular fingerprinting on the coliform isolates from the first analysis. The fourth analysis looked at the antibiotic resistance of fecal strep, with the assumption that if the organisms were from the same source, they would be equally or similarly resistant to antibiotics. The fifth analysis was to identify caffeine and surfactants in the private wells to determine if ground water contamination was from septic systems. The sixth and final analysis compared total nitrogen values for the wells sampled in January 1999 to total nitrogen values reported by the USGS with the assumption that increasing total nitrate levels indicate an animal waste source.
The following conclusions and recommendations were drawn from the investigation:
- There is no compelling data to support the contention that the ground water is contaminated with bacteria, but the data strongly suggest that the bacterium stems from pipes of the well apparatus.
- There is no data to support the contention that the bacteria in the private wells originated at the Circle Four Farms wastewater lagoons or the result of the back siphoning event.
- There is no data to support the contention that the Beaver River/canal system is the source of bacteria in the pipes of the private wells.
- The limited caffeine and surfactant data do not indicate septic tank seepage as the bacteria source.
- Data are insufficient to rule out a transient or very low level of bacteria in ground water that led to the contamination of the pipes in the private wells.
- DEQ and the Southwest Utah Public Health Department recommend that private well owners test their wells at least annually for total coliform.
- If positive for total coliform, the water should be considered a health risk and should not be consumed unless it is boiled first. Resample as soon as possible.
- If retest is positive for coliform, disinfect the water system after consulting the Southwest Public Health Department on the latest chlorination procedures.
This investigation was important because it investigated a potential health risk and indicated that ground water was not the source of the bacteria in the private wells, and provided recommendations to private well owners for sampling and disinfecting their wells. Information from this investigation was applied to the January 2005 flood event in the Escalante Desert where infiltration of contaminated surface waters into earth fissures prompted a private drinking water well test advisory from DWQ on April 7, 2005.
|Ground Water Bacterial Investigation in the Milford Valley – http://www.waterquality.utah.gov/documents/milford.pdf
An Evaluation of Health Concerns in Milford, Utah and the Possible Relationship to Circle Four Farms to those Concerns – http://www.waterquality.utah.gov/documents/Milfdrpt_2-2001.pdf
Beaver County Wells Weren’t Tainted by Hog Farms: Salt Lake Tribune – http://archive.li.suu.edu/docs/ms122/PP/water10.pdf