Chromium (total)
U.s.n., San Nicolas Island
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 | ND | 2 | 0 | ND |
| 2019 | ND | 2 | 0 | ND |
| 2020 | 10.00 ppb | 2 | 1 | ND - 20.0 ppb |
| 2021 | ND | 3 | 0 | ND |
| 2022 | 5.00 ppb | 2 | 1 | ND - 10.00 ppb |
| 2023 | ND | 2 | 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 |
|---|---|---|
| 2018-04-03 | CA5610702_001_001-201804030545 | ND |
| 2018-04-03 | CA5610702_002_002-201804030530 | ND |
| 2019-04-09 | CA5610702_002_002-201904090500 | ND |
| 2019-04-09 | CA5610702_001_001-201904090425 | ND |
| 2020-04-14 | CA5610702_001_001-202004140530 | 20.0 ppb |
| 2020-04-14 | CA5610702_002_002-202004140530 | ND |
| 2021-04-06 | CA5610702_001_001-202104060630 | ND |
| 2021-04-06 | CA5610702_002_002-202104060645 | ND |
| 2021-04-06 | CA5610702_002_002-202104060645 | ND |
| 2022-04-05 | CA5610702_001_001-202204050400 | 10.00 ppb |
| 2022-04-05 | CA5610702_002_002-202204050430 | ND |
| 2023-04-11 | CA5610702_002_002-202304110645 | ND |
| 2023-04-11 | CA5610702_001_001-202304110615 | ND |