Chromium (total)
North Castle 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 | 6.60 ppb | 1 | 1 | 6.60 ppb |
| 2019 | 2.50 ppb | 1 | 1 | 2.50 ppb |
| 2020 | 0.250 ppb | 4 | 1 | ND - 1.000 ppb |
| 2021 | ND | 4 | 0 | ND |
| 2022 | 0.525 ppb | 4 | 2 | ND - 1.10 ppb |
| 2023 | ND | 4 | 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 | AU15715-INP | 6.60 ppb |
| 2019-08-05 | AV16473-INP | 2.50 ppb |
| 2020-02-25 | AW03849-INP | 1.000 ppb |
| 2020-02-25 | AW03859-INP | ND |
| 2020-07-21 | AW13840-INP | ND |
| 2020-07-29 | AW14500-INP | ND |
| 2021-03-02 | AX04048-INP | ND |
| 2021-03-03 | AX04220-INP | ND |
| 2021-07-06 | AX13095-INP | ND |
| 2021-08-04 | AX15708-INP | ND |
| 2022-03-01 | AY03626-INP | ND |
| 2022-03-01 | AY03624-INP | 1.000 ppb |
| 2022-07-19 | AY12488-INP | 1.10 ppb |
| 2022-07-21 | AY12752-INP | ND |
| 2023-03-21 | AZ05013-INP | ND |
| 2023-03-21 | AZ05021-INP | ND |
| 2023-07-10 | AZ12340-INP | ND |
| 2023-08-28 | AZ15886-INP | ND |