WHY TEST?
Although Idaho’s ground water quality is generally good, monitoring shows that water has been significantly degraded in specific areas. Three more commonly found constituents in Idaho’s ground water include nitrate, arsenic, and uranium.
DEFINITIONS AND SIDE EFFECTS:
NITRATE
Nitrate is an inorganic chemical contaminant common to drinking water systems in Idaho. High levels of nitrate can cause serious health effects, especially for young children. Nitrate comes from septic and sewer systems, waste from animal feedlots, nitrogen-based fertilizers, and natural deposits. Runoff from irrigation, flooding, and precipitation often leads to seasonal peaks in drinking water nitrate levels. Nitrate is one of the most widespread ground water contaminants in Idaho. Nitrate is a compound containing nitrogen, an element which is avital component of foods and fertilizers. It’s also an essential nutrient for plant growth. Nitrate comes from a variety of sources such as 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 release nitrate to the environment. Health Effects – Nitrate exposure can have serious health effects, but certain groups are particularly vulnerable, including people with pre-existing health conditions, pregnant women, and young children under the age of six months. Infants who drink water containing nitrate above the MCL can become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome, also known as Methemoglobinemia. This condition can occur rapidly, over the course of just a few days. Do not attempt to remove nitrate from drinking water by boiling it. This will concentrate nitrate levels. Private Wells – It is the well owner’s responsibility to maintain the well and ensure that the water is safe to drink. Private well owners should test for nitrate at least annually. Livestock, such as cattle and sheep, also can be poisoned by high levels of nitrate (over 100 mg/L).
ARSENIC
Arsenic is a naturally occurring element found in the earth’s crust. Trace amounts are found in all living matter, including rocks, soil, water, air, plants, and animals. Arsenic is a well-known chemical element used in the manufacturing of agricultural chemicals such as pesticides, weed killers, and rodenticides. It is also used to produce paints, dyes, metals, drugs, soaps, and semiconductors. Approximately 90% of industrial arsenic in the United States is used as a wood preservative. Arsenic can be released into the environment through natural activities such as volcanic action, erosion, forest fires, or through human activities such as pesticide application, improper disposal of arsenic-containing waste chemicals, agricultural applications, mining, and smelting. Arsenic Standard – EPA’s drinking water standard for arsenic is 10 parts per billion (ppb). The standard applies to all community water systems and non-transient non-community water systems in Idaho. Arsenic and Drinking Water – Most arsenic in drinking water comes from natural rock formations. Water that encounters rock formations can dissolve arsenic and carry it into underground aquifers, streams, and rivers that may be used as drinking water sources. Arsenic deposited on the ground from industrial or agricultural uses tends to persist in the top few feet of soil and is not likely to have a significant impact on most aquifers. When dissolved in water, arsenic has no smell, taste, or color, even at high concentrations. Health Impacts of Arsenic Exposure – Arsenic is associated with more than 30 different adverse health effects, including cardiovascular disease, diabetes mellitus, skin changes, nervous system damage, and various forms of cancer. Although a very high dose (60,000 micrograms) of arsenic can be lethal, the amount of arsenic in drinking water is very small, and any drinking water-related health effects are the result of prolonged exposure over time. People may have different responses to the same arsenic exposure depending on dose, duration, general health, age, and other factors. Reducing the amount of arsenic in drinking water will lessen exposure and reduce the risk of adverse health effects. Incidence of Arsenic – Western states have higher arsenic levels as compared to the rest of the United States. Parts of the Midwest and New England also have areas where arsenic levels are elevated. While many areas may not have detected arsenic in their drinking water above 10 ppb, there may be geographic hot spots with higher levels of arsenic than in surrounding areas. Arsenic is a problem in some parts of Idaho. Data compiled by the Idaho Department of Water Resources show that concentrations of arsenic in ground water are highest in the southwestern Idaho counties of Elmore, Gem, Owyhee, and Washington; Kootenai County in northern Idaho; and Jefferson County in eastern Idaho. Other counties have moderate or only trace amounts of arsenic in historic ground water samples. All community water systems are required to include health information and arsenic concentrations in their annual drinking water Consumer Confidence Report to DEQ for water that exceeds 5 ppb.
URANIUM
Uranium is a radioactive element (radionuclide) that occurs naturally in rock, soil, and water, usually in low concentrations. Radionuclides are unstable atoms with excess energy that emit radiation as radionuclides decay. The uranium decay sequence also includes other radionuclides of concern such as radium and radon. Long-term exposure to elevated levels of uranium in drinking water can result in kidney damage. Individual risk depends on many factors, including the concentration of uranium in the water, the duration and volume of consumption, and the age and health of the individual. The drinking water standard for public water systems is 30 parts per billion (ppb). The standard applies to public water systems, but private well owners should adhere to it as well. There is currently no Idaho ground water quality standard for uranium. It is recommended that testing for uranium be done once every 3 to 5 years.
LEAD
Lead is a toxic metal that was commonly used in consumer products such as gasoline and paint before it was discovered that it is harmful to human health. We now know that, if inhaled or swallowed, lead can build up in the body over time and cause serious damage to the brain, kidneys, nervous system, and red blood cells. The problem of airborne lead exposure has been largely resolved in the United States as a result of the phase-out of leaded gasoline. Today, exposure is more likely to come from lead-contaminated soil or dust and drinking water through the corrosion of plumbing. Impacts of Lead Exposure – Exposure to lead is most dangerous for young children under the age of six and infants. A dose of lead that would have little effect on an adult could have a big effect on a small body. The primary sources of lead exposure for most children are deteriorating lead-based paint, lead-contaminated dust, and lead-contaminated residential soil. On average, it is estimated that lead in drinking water accounts for 10% to 20% of total lead exposure in young children. Lead exposure in drinking water may be as high as 60% in infants whose diet consists mostly of liquids made with lead-contaminated water. Lead and Drinking Water – Certain drinking water plumbing, older fixtures, or solder may contain lead. The most common cause of lead in drinking water is corrosion, a reaction between water and lead pipes or solder. Lead may be present in your drinking water if your home has faucets or brass fittings that contain lead, or if your home or water system (service line and internal plumbing) has lead or copper pipes with solder that contains lead. Lead can be present in school drinking water as well, particularly when water sits overnight, over a weekend, or during a vacation. The lead concentration depends on the plumbing materials and the corrosivity of the water.
FLUORIDE
Fluoride is a naturally occurring compound derived from fluorine—the earth’s 13th most abundant element. It is found in many rocks and minerals and can enter drinking water as water passes through soil. Fluoride is naturally present in almost all foods and beverages, including water. Few public water systems in Idaho add fluoride to the drinking water—a process known as fluoridation. Fluoride Regulation – Fluoride has been shown to prevent tooth decay, but too much fluoride at an early age can cause discoloration and pitting of the teeth. This condition is known as dental fluorosis. Overexposure to fluoride over a lifetime can lead to certain bone diseases.
COLIFORM BACTERIA
Coliform bacteria are organisms that are present in the environment and in the feces of all warm-blooded animals and humans. Coliform bacteria will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system. Most pathogens that can contaminate water supplies come from the feces of humans or animals. Role of Coliforms in Detecting Contamination – Testing drinking water for all possible pathogens is complex, time-consuming, and expensive. It is relatively easy and inexpensive to test for coliform bacteria. Total coliform testing is used as an indicator of potential contamination. Total Coliform, Fecal Coliform, and E. Total Coliform Circle Graphic: outer circle is total coliform, second layer is fecal coliform, and the core it E. colicoli – Total coliform bacteria are commonly found in the environment (e.g., soil or vegetation) and are generally not harmful. However, if environmental contamination can enter the system, there may also be a way for pathogens to enter the system. Fecal coliform bacteria are a sub-group of total coliform bacteria. They appear in great quantities in the intestines and feces of people and animals. The presence of fecal coliform in a drinking water sample often indicates recent fecal contamination, meaning that there is a greater risk that pathogens are present than if only total coliform bacteria is detected. E. coli is a sub-group of the fecal coliform group. The presence of E. coli in a drinking water sample almost always indicates recent fecal contamination, meaning there is a greater risk that pathogens are present. Responses to Coliform Detection – When coliform bacteria are found, water systems investigate to find out how the contamination got into the water. They collect additional, or “repeat,” water samples for testing, and often inspect the entire system. Taking repeat samples helps determine whether an actual problem exists in the system. If any of the repeat samples detect coliform bacteria, the initial findings are considered confirmed. If total coliform bacteria are confirmed in your drinking water, your water system should be inspected to find and eliminate any possible sources of contamination. Once the source is identified, it can usually be resolved by making system repairs, flushing, and adding chlorine for a short period of time. Confirmation of fecal coliform bacteria or E. coli in a water system indicates recent fecal contamination, which may pose an immediate health risk to anyone consuming the water.