Much of Idaho suffers from groundwater pollution by nitrates.
Ada and Canyon counties are listed as the second-worst polluted area in the state by the Idaho Department of Environmental Quality. Twin Falls is the worst and Weiser is listed as the third-worst.
DEQ is asking private well owners in the Weiser area who receive sampling request letters to participate in a nitrate well sampling project this spring.
DEQ has established criteria for determining which wells to sample based on location, age and depth of the well, and whether a complete well log is available. Letters seeking permission to sample will be sent within the next three weeks.
Nitrate is a chemical form of nitrogen found in soil and water. In elevated levels, nitrates can present a risk to human health. Nitrate priority areas are areas where 25% of the sampled wells contain water with nitrate levels of 5 milligrams per liter or greater. The drinking water standard is 10 mg/L.
Short-term exposure to even fairly large amounts of nitrate produces no immediate health effects. However, babies, people in poor health and the elderly can be susceptible to problems from short-term nitrate exposure. Infants younger than six months of age are especially sensitive to nitrate poisoning, which reduces the amount of oxygen in their blood, causing shortness of breath and blueness of the skin. This condition, often called blue baby syndrome, can cause the baby’s health to deteriorate rapidly over a period of days.
Nitrate comes from a variety of sources, including plants and other organic matter that return nitrate to the soil as they decompose. Septic sewer systems, waste from animal feedlots and nitrogen-based fertilizers also discharge nitrates to the environment.
Nitrate that is not used by plants can build up in and move through the soil. Precipitation, irrigation and sandy soils allow nitrate to move around and find its way into surface water and groundwater.
While nitrate is just one of the potential groundwater contaminants in Idaho, more is known about nitrate in groundwater in Idaho than other contaminants. In addition, the presence of nitrate is a good indicator of other potential water quality problems.