Colorado State University Cooperative Extension, in cooperation with the Colorado Department of Agriculture, collected water samples last year to evaluate how the use of pesticides and nitrates commonly used in agriculture are affecting shallow groundwater. They tested 49 wells.In a news release, CSU stated, ìin general, the survey found that the groundwater quality in El Paso County is very good.î CSU Director Gary Hall later admitted the statement should have been better qualified. Unfortunately, local newspapers reported the original statement. In Jennifer Wilsonís March 28 Gazette article, ìMost of county wells are safe,î her first sentence reads, “Tests on a sampling of El Paso County wells show most rural residents have safe drinking water, state officials said Wednesday.”Hall presented the sampling results in a public meeting March 7. He said wells were selected to include the most shallow wells in the areas of greatest concern, namely along stream channels down gradient of agricultural activities. The news release stated, “These (alluvial wells) are shallower wells, 100 feet or less, that could be more easily affected by surface activities.” However, Hall said they did not evaluate the well depth, construction, or measure the depth to water. Evaluating well construction is important in determining what the analysis represents.Karl Mauch of the Colorado Department of Agriculture said nine of the 49 wells sampled are from the Denver Basin Bedrock Aquifers. The map showing sample locations shows 10 of the 49 wells are in the Upper Black Squirrel Designated Basin.There are two essential questions to answer: Does the absence of pesticides and the low levels of nitrates detected in the 49 wells imply the water at those locations is “safe to drink?î Do the results from water samples collected at 49 locations suggest that well water from the remaining 22,000-plus wells in El Paso County is safe as well?The Safe Drinking Water Act passed in 1974 gives the EPA the authority to set drinking water standards. These standards are divided into two broad categories: primary standards and secondary standards. Primary standards protect drinking water quality by limiting the levels of contaminants that can adversely affect public health and are known or anticipated to occur in water. There are nearly 100 chemical and biological primary drinking water standards. There are also secondary drinking water standards established for aesthetic effects. EPA regulates municipal water supplies having 15 or more taps or serving 25 or more individuals. For private wells, the well owner must ensure the safety of his or her well water. CSU stated they tested for 47 pesticides in addition to nitrates. It can be claimed with reasonable certainty that at 49 locations, pesticides were not detected and at 48 of the 49 locations, nitrates were detected and within EPA drinking water standards. Incidentally, the significance that nitrates were detected at 48 locations and should be monitored on an annual basis was not addressed. And, what of the metals, volatile organic compounds (VOCs) or microbiological agents? Even El Paso County Health requires new homeowners to check for coliform. It cannot be stated that metals, VOCs or coliform are at acceptable levels without testing for them. The answer to whether the water is “very good” or “safe to drink” without a complete analysis is a firm “No.” Likewise, it would be nothing short of irresponsible to draw conclusions from the results at 49 locations and apply it to all 22,000-plus wells or even one well at a different location.Using EPA drinking water standards as a basis for testing well water is a logical approach when evaluating drinking water quality. Indeed, water testing can be costly. Comprehensive regulatory-compliance water tests can run into the thousands. Since well owners do not fall under regulatory requirement, a complete drinking water analysis with less stringent controls can be obtained for under $300. This analysis will include not just pesticides and nitrates, but also include volatile organic compounds, metals, general physical parameters and coliform.It’s your drinking water; your health is certainly worth the investment.Julia Murphy is a hydrogeologist who spent 10 years in groundwater sampling and analysis for compliance to Environmental Protection Agency drinking water regulatory requirements.
