Nitrate and nitrite
City of Wilsonville
Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 0.508 ppm | 4 | 4 | 0.270 ppm - 0.810 ppm |
| 2019 | 0.555 ppm | 4 | 4 | 0.300 ppm - 0.780 ppm |
| 2020 | 0.475 ppm | 4 | 4 | 0.230 ppm - 0.920 ppm |
| 2021 | 0.593 ppm | 3 | 3 | 0.320 ppm - 1.10 ppm |
| 2022 | 0.665 ppm | 2 | 2 | 0.630 ppm - 0.700 ppm |
| 2023 | 0.910 ppm | 1 | 1 | 0.910 ppm |
ppm = parts per million
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.14 ppm
The EWG health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.
EPA Maximum Contaminant
Level (MCL): 10 ppm
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-10 | 201712040042-I | 0.810 ppm |
| 2018-04-11 | 201803050004-I | 0.680 ppm |
| 2018-07-18 | 201807190944-I | 0.270 ppm |
| 2018-10-10 | 201809030044-I | 0.270 ppm |
| 2019-01-09 | 201812030009-I | 0.710 ppm |
| 2019-04-10 | 201904110241-I | 0.780 ppm |
| 2019-07-10 | 201907110430-I | 0.430 ppm |
| 2019-10-08 | 201910090408-I | 0.300 ppm |
| 2020-01-02 | 202001030119-I | 0.920 ppm |
| 2020-04-15 | 202004160157-I | 0.470 ppm |
| 2020-07-15 | 202007160188-I | 0.280 ppm |
| 2020-10-14 | 202010150105-I | 0.230 ppm |
| 2021-01-06 | 202101070374-I | 1.10 ppm |
| 2021-04-14 | 202104150878-I | 0.360 ppm |
| 2021-08-02 | 202108030084-I | 0.320 ppm |
| 2022-02-02 | 202202030907-I | 0.700 ppm |
| 2022-04-13 | 202204140832-I | 0.630 ppm |
| 2023-01-11 | 380-34174-2-I | 0.910 ppm |