Nitrate and Nitrite are found worldwide as water and wastewater pollutants. Whether results are expressed in their ionic form (NO3– and NO2-), or expressed as nitrogen (NO3-N & NO2-N respectively), these molecules are considered ‘acute’ contaminants in drinking water. Excessive levels of nitrate in drinking water have caused serious illness and sometimes death, especially in young infants. In addition to causing blue-baby syndrome (methemoglobinemia) in infants, nitrate and nitrite are also linked to hypertension and cancer. Nitrates are converted into nitrites in the body, which is why both can be dangerous. The US EPA has set a maximum contaminant limit (MCL) for NO3-N at 10 mg/L and 1 mg/L for NO2-N. Additionally, the summation of Nitrate and Nitrite (as nitrogen) cannot exceed 10 mg/L in a sample.
The EPA and States require water purveyors to monitor nitrate annually, and at least once every nine years for nitrite, in both surface and groundwater sources. All new sources must initially be monitored for four consecutive quarters for nitrate after start of operation. Increased monitoring for these pollutants is required if analytical results exceed half the MCL for either compound.
The Rule Manager in SAMSWater is an excellent tool to help water utilities manage their nitrate (and nitrite) test results and remain compliant with monitoring schedules. Algorithms test every analytical result uploaded into SAMSWater for compliance status. For Nitrate/Nitrites results, the rule tests to see if any exceedance has occurred to include:
- Does the initial analytical result exceed the MCL?
- Does the result equal or exceed half the MCL?
- Does the initial four-quarter running annual average exceed the MCL?
- Does the initial four-quarter samples equal or exceed half the MCL?
- Does the average of the initial and confirmation sample exceed the MCL?
- Is the average of the initial and confirmation sample below the MCL?
If the rule detects any regulatory ‘exceedance,’ action text is generated and designated SAMS users are notified immediately by E-mail and/or alerts posted on the User’s Dashboard. Alerts generated by the Rule Manager are very specific and often site the EPA/State requirements per regulation. For example, a sample result exceeding half the nitrate MCL (I.E. greater >= 5 mg/L), the following action E-mail would be sent:
A nitrate sample has equaled or exceeded 50% of the MCL, therefore you need to start a quarterly monitoring frequency for at least one year. After four consecutive quarterly samples are less than the MCL, you may request that the State Board reduce monitoring frequency to annual sampling.
While Rules are tailored to meet EPA and/or State regulatory requirements, there are no limitations to how they may be used. Rules can be customized to include internal limits, or conditions with customized alerts sent to staff to meet your needs.
Rules in SAMSWATER have been created for Inorganic (IOC), Volatile Organic (VOC), Synthetic Organic (SOC), Radiological (RAD), Perchlorate, Asbestos, Lead & Copper, Coliform, and others. The Rule Manager is accessed through Admin Management found on the tool bar. User permissions are needed to access this module so that saved rules are protected. Contact SAMS staff to learn more about this powerful tool. We would be happy to discuss your specific needs.