Chromium (total)
Mitchell County Rural Water District 2
Chromium is a naturally occurring metal, but industrial uses can elevate its levels in water. One form, hexavalent chromium, causes cancer. Total chromium is not a good indicator of the amount of hexavalent chromium in drinking water.
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 | 2.10 ppb | 1 | 1 | 2.10 ppb |
| 2019 | 3.10 ppb | 1 | 1 | 3.10 ppb |
| 2020 | 2.10 ppb | 1 | 1 | 2.10 ppb |
| 2021 | 1.10 ppb | 1 | 1 | 1.10 ppb |
| 2022 | ND | 1 | 0 | ND |
| 2023 | ND | 1 | 0 | ND |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EPA Maximum Contaminant
Level (MCL): 100 ppb
The legal limit for total chromium, established in 1991, was based on a 1958 toxicity study in laboratory animals, and applies to both the less-toxic trivalent chromium and the more-toxic hexavalent chromium forms of this compound. This limit does not protect against the risk of cancer from ingestion of hexavalent chromium.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-04-17 | 937706 | 2.10 ppb |
| 2019-04-22 | 1138154 | 3.10 ppb |
| 2020-04-13 | 1356556 | 2.10 ppb |
| 2021-04-12 | 1816200 | 1.10 ppb |
| 2022-04-19 | 2239682 | ND |
| 2023-04-04 | 2477929 | ND |