Chromium (total)
North Castle Water District #4
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 | 7.55 ppb | 2 | 2 | 7.30 ppb - 7.80 ppb |
| 2019 | 2.30 ppb | 2 | 2 | 2.00 ppb - 2.60 ppb |
| 2020 | 0.333 ppb | 6 | 2 | ND - 1.000 ppb |
| 2021 | ND | 6 | 0 | ND |
| 2022 | 0.417 ppb | 6 | 2 | ND - 1.40 ppb |
| 2023 | ND | 6 | 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 | AU15716-INP | 7.80 ppb |
| 2018-07-24 | AU15718-INP | 7.30 ppb |
| 2019-08-05 | AV16474-INP | 2.60 ppb |
| 2019-08-05 | AV16471-INP | 2.00 ppb |
| 2020-02-25 | AW03861-INP | ND |
| 2020-02-25 | AW03855-INP | 1.000 ppb |
| 2020-02-25 | AW03853-INP | 1.000 ppb |
| 2020-07-13 | AW13180-INP | ND |
| 2020-07-29 | AW14499-INP | ND |
| 2020-08-27 | AW16635-INP | ND |
| 2021-03-02 | AX04052-INP | ND |
| 2021-03-03 | AX04226-INP | ND |
| 2021-03-03 | AX04224-INP | ND |
| 2021-07-06 | AX13097-INP | ND |
| 2021-08-03 | AX15569-INP | ND |
| 2021-08-03 | AX15556-INP | ND |
| 2022-03-01 | AY03618-INP | 1.10 ppb |
| 2022-03-01 | AY03622-INP | 1.40 ppb |
| 2022-03-01 | AY03616-INP | ND |
| 2022-07-19 | AY12490-INP | ND |
| 2022-07-20 | AY12624-INP | ND |
| 2022-07-21 | AY12753-INP | ND |
| 2023-03-21 | AZ05017-INP | ND |
| 2023-03-21 | AZ05015-INP | ND |
| 2023-03-22 | AZ05102-INP | ND |
| 2023-07-10 | AZ12341-INP | ND |
| 2023-07-10 | AZ12342-INP | ND |
| 2023-07-25 | AZ13469-INP | ND |