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Nitrates, arsenic found in local wells Monday Jan 23, 2017 at 6:25 PM Jan 24, 2017 at 3:18 PM Mark Freeman Mail Tribune @MTwriterFreeman A new study shows pockets of groundwater outside of Medford and Central Point contain high levels of nitrates and arsenic but that only a handful of wells tested in the study revealed unhealthy levels of contaminants. The new state Department of Environmental Quality program echoes similar studies over the past few decades as well as recent data collections on wells during rural home sales that collectively wave a red flag for rural residents to have their water tested regularly, authorities said. While 21 percent of wells tested had higher levels of nitrates than considered "background," just 4 percent had higher than recommended health levels, and that's actually lower than data in previous studies as well as collected during rural home sales, according to the DEQ. "I was a little bit surprised that we didn't see too many nitrate levels above the maximum," said Aaron Borisenko, water-quality monitoring manager at DEQ's lab in Hillsboro. "I thought we'd get something more in line with other work that's been done there." Nitrates are found in fertilizers and other agricultural products. Presence of nitrates in drinking water can cause a variety of chronic and acute effects, according to the Oregon Health Authority. Infants are at a particularly strong risk for blue baby syndrome, which can cause death, according to the OHA. Twenty-two percent of the wells tested contained arsenic, which is found naturally in areas with volcanic activity. But 6 percent had unhealthy levels, exposure to which can cause health problems in infants, pregnant women and others, according to the report. In almost all of those cases, the landowners already knew their wells had issues with arsenic and were already treating their water for it, Borisenko said. Long-term exposure to arsenic can lead to skin lesions, damage to the circulatory and nervous systems and can cause some forms of cancer, according to the OHA. The DEQ data is considered baseline and can be used as a benchmark for future testing to measure changes in groundwater contamination, but the DEQ currently has no plans to do that testing, Borisenko said.   "We definitely don't have the data to talk about trends," he said. The study does not investigate sources of the contamination nor does it assess health risks, according to the report. Also, no geology or hydrology study accompanied the sampling study, according to the DEQ. The study is based on two sets of samples collected in 2015 as part of the DEQ's launch of its new Statewide Groundwater Monitoring Program created to establish the status of what it calls "ambient groundwater conditions" in some of Oregon's more vulnerable aquifers. The findings were based on samples from 107 mostly private wells from volunteer owners who received full reports on their well water in exchange for participation. The study area stretched along the Rogue River from Shady Cove to Grants Pass and along the Bear Creek Basin from Central Point to areas southeast of Ashland. Among some of the findings: At least one pesticide or chemical resulting from the breakdown of a pesticide was detected in 38 percent of the wells. However, all the readings were "well below" levels considered a threat to human health, according to the DEQ. Coliform bacteria were detected in 43 percent of wells tested, which could indicate contamination of the aquifer but most commonly is associated with individual well construction or sealing. Bacteria can enter a well if the well sealing is broken or the well is poorly constructed or failing. Reach Mail Tribune reporter Mark Freeman at 541-776-4470 or [email protected]. Follow him on Twitter at www.twitter.com/MTwriterFreeman.   Arsenic levels found in sampling of Jackson County wells by Mail Tribune on Scribd   Nitrate levels found in sampling of Jackson County wells by Mail Tribune on Scribd