Chromium (total)
North Castle Water District #5
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 | 6.40 ppb | 1 | 1 | 6.40 ppb |
| 2019 | 1.000 ppb | 1 | 1 | 1.000 ppb |
| 2020 | ND | 2 | 0 | ND |
| 2021 | ND | 2 | 0 | ND |
| 2022 | 0.600 ppb | 2 | 1 | ND - 1.20 ppb |
| 2023 | ND | 3 | 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 |
|---|---|---|
| 2018-07-24 | AU15719-INP | 6.40 ppb |
| 2019-08-05 | AV16475-INP | 1.000 ppb |
| 2020-02-25 | AW03851-INP | ND |
| 2020-07-21 | AW13838-INP | ND |
| 2021-03-02 | AX04050-INP | ND |
| 2021-07-06 | AX130091-INP | ND |
| 2022-03-01 | AY03628-INP | 1.20 ppb |
| 2022-07-20 | AY12577-INP | ND |
| 2023-03-21 | AZ05019-INP | ND |
| 2023-07-10 | AZ12339-INP | ND |
| 2023-09-12 | AZ16819-INP | ND |