On August 3, the Albany County / Laramie Environmental Advisory Committee received the results of US Geological Survey sampling (USGS 8_3_17 slides) of two monitor wells on the east side of town drilled as part of the 2015 Laramie Monitor Well Program. The “Imperial Heights Park South” well is off the northwest corner of the Sherman Hills Subdivision; the “Triangle” well is at the intersection of Vista Dr. and Grand Ave. These wells were not located within areas served by septic systems, but were sited to monitor groundwater quality between such areas and the City’s Turner Wellfield.
Consistent with the City report, but including a much larger set of chemicals, the USGS sampling found nothing in excess of EPA-established maximum contaminant limits for drinking water.
Nitrates, sodium, and chlorides were described as “elevated” relative to other Casper Aquifer wells in the area. Isotopic analysis of nitrates ruled out fertilizer and precipitation sources, but could not distinguish between septic waste and natural soil contributions.
The samples were also analyzed for 65 different “wastewater compounds” that are “common in septic system effluent”, like caffeine and birth-control hormones. None were detected. Thus, the information from these two wells indicates these contaminants that may be present within the areas of septic systems are not making their way toward the city wells at detectable concentrations.
Tritium analysis indicates the groundwater at these locations recharged the aquifer later than the 1950s.
