Nitrate and nitrite
St. Charles County PWSD 2
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.
16
Samples
0
Samples exceeding legal limit (MCL)
6
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.0190 ppm | 1 | 1 | 0.0190 ppm |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | 0.247 ppm | 3 | 2 | ND - 0.730 ppm |
| 2017 | 0.0885 ppm | 4 | 2 | ND - 0.320 ppm |
| 2018 | 0.843 ppm | 4 | 3 | ND - 1.61 ppm |
| 2019 | 0.0798 ppm | 4 | 3 | ND - 0.280 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EWG Health Guideline 0.14 ppm
The 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 |
|---|---|---|
| 2014-06-09 | AC27108 | 0.0190 ppm |
| 2016-09-20 | AC84404 | ND |
| 2016-09-20 | AC84402 | 0.730 ppm |
| 2016-09-20 | AC84403 | 0.0120 ppm |
| 2017-09-07 | AD06775 | 0.320 ppm |
| 2017-09-07 | AD06777 | ND |
| 2017-09-07 | AD06776 | ND |
| 2017-09-07 | AD06778 | 0.0340 ppm |
| 2018-09-18 | AD33435 | ND |
| 2018-09-18 | AD33436 | 0.940 ppm |
| 2018-09-18 | AD33437 | 0.820 ppm |
| 2018-09-18 | AD33438 | 1.61 ppm |
| 2019-09-24 | AD55696 | 0.0260 ppm |
| 2019-09-24 | AD55697 | 0.280 ppm |
| 2019-09-24 | AD56582 | 0.0130 ppm |
| 2019-09-24 | AD56583 | ND |