Nitrates are chemical compounds containing nitrogen and oxygen that can dissolve in water. While naturally present at low levels, elevated concentrations in drinking water can indicate contamination. Understanding how to test for these compounds is a practical step for assessing water quality.
Why Test for Nitrates in Water
Nitrate contamination in water often stems from agricultural runoff (including fertilizers and manure) or failing septic systems, allowing nitrates to seep into groundwater and surface water. Consuming water with high nitrate levels can pose health risks, particularly for infants under six months old. It can interfere with the blood’s ability to carry oxygen, a condition known as “blue baby syndrome” or methemoglobinemia. Excessive nitrates also contribute to environmental issues like eutrophication, which harms aquatic ecosystems.
Home Water Testing Kits
Home water testing kits offer a convenient initial assessment for nitrate levels. These kits typically come in two main forms: test strips and colorimetric kits. Test strips involve dipping a treated strip into a water sample, and the strip changes color based on the nitrate concentration. Colorimetric kits often require adding specific reagents to a water sample, which then react to produce a color intensity proportional to the nitrate content, often compared against a color chart.
To perform a test, collect a water sample according to the kit’s instructions, usually from a cold water tap after letting it run for a few minutes. Carefully follow the manufacturer’s directions for adding reagents or dipping the test strip. Note the kit’s specified reaction time; reading results too early or too late can lead to inaccurate readings. Common pitfalls include using expired kits, improper storage that degrades reagents, or failing to read results in appropriate lighting. While home kits provide a quick indication, their accuracy can vary, generally offering a range rather than a precise measurement.
Professional Water Testing Services
For precise, comprehensive water quality analysis, submitting samples to a certified laboratory is a reliable option. Individuals choose professional testing for higher accuracy, especially if they suspect contamination or require results for legal or property transactions. The process involves finding an environmental testing laboratory certified by a state or national accreditation body, such as the EPA’s Environmental Laboratory Accreditation Program (ELAP). The laboratory provides a sterile sample collection kit and specific instructions for collecting and preserving the water sample, crucial for maintaining integrity during transport.
Once the sample is collected, it must be shipped to the lab within a specified timeframe, often within 24-48 hours, to ensure accurate results. Laboratories use advanced analytical methods, such as ion chromatography or spectrophotometry, to detect nitrate concentrations with high precision. The turnaround time for results can vary, usually ranging from a few days to a couple of weeks, depending on the lab’s workload and the specific tests requested.
Interpreting Nitrate Levels
Interpreting results from home kits or professional reports involves recognizing units of measurement. Nitrate concentrations are commonly expressed in parts per million (ppm) or milligrams per liter (mg/L), equivalent units. The primary reference point for drinking water safety in the United States is the Environmental Protection Agency’s (EPA) maximum contaminant level (MCL) for nitrates. The EPA has set the MCL for nitrates at 10 mg/L (or 10 ppm) as nitrogen (N), meaning the concentration refers to the nitrogen component of the nitrate molecule.
If a test result indicates nitrate levels at or above the 10 mg/L MCL, the water is considered unsafe for consumption, especially for infants. Even levels below the MCL might warrant ongoing monitoring, particularly if there are known sources of contamination nearby or if the levels show an increasing trend over time. Regular testing helps to track changes and identify potential risks before they reach concerning levels.
Managing High Nitrate Concentrations
If water tests reveal high nitrate concentrations, immediate action is necessary to protect health. For drinking and cooking, using an alternative water source, such as bottled water, is a practical interim solution. For long-term management, various treatment options can effectively reduce nitrate levels. Point-of-use filtration systems, installed at a single tap, are a common choice.
Reverse osmosis systems are effective at removing nitrates, forcing water through a semi-permeable membrane that blocks larger nitrate molecules. Ion exchange is another effective method, using a resin to swap nitrate ions for other ions, such as chloride. Addressing the source of contamination is also important. This might involve improving septic system maintenance, adjusting fertilizer application practices, or implementing wellhead protection measures to prevent surface runoff from entering the well. Consulting with local health authorities or water quality experts can provide tailored advice and guidance for specific situations.