Oregon's Groundwater Quality Protection Act
The Oregon Groundwater Quality Protection Act says that if widespread groundwater contamination is believed to have resulted from non-point source pollution, DEQ must take certain steps to assist the community in reducing this contamination. These steps included:
- Research to help the community better understand the causes of the contamination,
- Education & Public Outreach to share what is known about groundwater and how to protect it for the future, and
- Community Involvement to assist local leaders in identifying the public's needs and desires related to the groundwater resource.
What is non-point source pollution?
Non-point source pollution comes from many individual activities rather than a single point such as a factory. Farms, forests, gardens, and city streets all contribute non-point source pollution.
According to the law, DEQ must declare a Groundwater Management Area (GWMA) if it is confirmed that the groundwater contains nitrate at 7 ppm (parts per million) as a result of non-point source pollution.
Once a Groundwater Management Area has been announced, DEQ must establish a local GWMA committee made up of affected citizens and other interested parties. The committee advises state agencies who are required to develop and implement an action plan that will reduce groundwater contamination in the area.
There are currently two other GWMAs in Oregon: One in the Hermiston area and one in the Ontario area.
Nitrate in the Southern Willamette Valley Groundwater
Nitrate is a common contaminant of shallow groundwater in areas with well-drained soils. It comes from fertilizers, septic systems, and animal manure. The US EPA has set 10 ppm (parts per million) as the maximum allowable level of nitrate in water delivered by public drinking water systems. There are no requirements for individual private wells.
Nitrate concentrations above the accepted background level of 2 ppm have been recorded in the Southern Willamette Valley since the 1930s, with level above 10 ppm not uncommon.
These elevated levels of nitrate in groundwater prompted scientists from DEQ and Oregon State University to take a closer look at the connections between groundwater and activities that may be causing widespread contamination from nitrate. (Browse Research page for reports).
Southern Willamette Valley Groundwater Study Area (2000-2002)
In 2000, to determine if there was a need to declare a groundwater management area, DEQ identified a groundwater study area that included all of the valley floor between Eugene and Albany.
DEQ staff sampled about 500 wells from Fall 2000 through Summer 2001. Of these, 100 had nitrate levels at or above 7 ppm. Most of those 100 wells were resampled during Summer 2002, with additional test done for pesticides and bacteria.
Generally, the nitrate levels were similar the second year. Pesticides were found at very low levels.
Nitrate Health Effects
The federal drinking water standard of 10 ppm of nitrate in drinking water was set half a century ago because there was evidence that a rare type of blue-baby syndrome called methemoglobinemia was associated with high levels of nitrate in drinking water. Since that time, a considerable amount of research has been done looking at health effects from drinking water with nitrate. Unfortunately, the evidence is mixed and no clear conclusions can be drawn at this time. The methemaglobinemia connection is being questioned and new conditions associated with high levels of nitrate are being suggested. Some evidence suggest that there may be adverse health effects from consuming water with nitrate below 10 ppm, other studies conclude that the 10 ppm standard is overly protective.