What is nitrate? It is a chemical made up of one part nitrogen and three parts oxygen that goes by the symbol NO3.
Nitrate can be present in water, in food, or in the air, and comes from sources like fertilizer, septic systems and animal waste. It isn’t usually found naturally in B.C.’s groundwater, so it is a sign of human impacts.
Nitrate is generally non-toxic, but in young babies high concentrations in water or food can reduce their blood’s ability to transport oxygen, sometimes causing “blue baby syndrome” and in extreme cases death can occur.
Residents of Grand Forks and the surrounding rural areas have been concerned about nitrate since testing in the 1980s showed high levels in certain areas.
Last year new studies revealed that nitrate levels are decreasing in Grand Forks’ municipal wells and do not pose a health risk. This was reassuring for city officials as they work to develop and safeguard our water supply.
In the rural area surrounding Grand Forks, nitrate levels are stable or gradually declining, according to a 2011 study by the Province of B.C. (http://a100.gov.bc.ca/pub/acat/public/viewReport.do?reportId=23602).
However, a number of wells have nitrate levels above drinking water quality guidelines, especially in the Darcy Road and Nursery areas, and along Carson Road.
High levels of potassium are also found at these wells, which means the nitrates are probably related to fertilizer use.
Little information is available on levels of nitrates in other aquifers in the region.
Well owners can monitor nitrate levels by testing wells at least annually. More information on testing is available from Interior Health Authority.
Prevention is the best way to protect groundwater sources from contamination by nitrates and other chemicals. Shallow sand and gravel aquifers such as those in Grand Forks, Midway and Beaverdell are particularly at risk from intensive agricultural and septic system contamination.
There are several ways landowners can protect groundwater.
For instance, reducing fertilizer use, conserving water, managing manure properly and building soil health can reduce leaching of chemicals and nutrients.
Siting wells properly and making sure that they are properly closed can also reduce the chance that contamination on the surface reaches the aquifer.
Land use planning that restricts residential development in rural areas can reduce the risk of contamination by septic systems.
These and other strategies will be the topic of future columns.
Do you get your well tested regularly? What steps have you taken to find out about or protect your drinking water supply?
– Contact Graham Watt (plan@kettleriver.ca) about this or any other watershed questions. Figures and footnotes are included online at http://kettleriver.ca – look for the menu item “Kettle River Q&A.” Watt is Kettle Watershed Management Plan project co-ordinator for the RDKB.