Chromium (total)
North Wales Water Authority
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 | 10 | 0 | ND |
| 2019 | ND | 1 | 0 | ND |
| 2020 | ND | 1 | 0 | ND |
| 2021 | 0.500 ppb | 8 | 4 | ND - 1.000 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 |
|---|---|---|
| 2018-02-06 | 8021845-01 | ND |
| 2018-03-05 | 8032061-02 | ND |
| 2018-03-05 | 8032061-03 | ND |
| 2018-03-05 | 8032061-04 | ND |
| 2018-03-05 | 8032061-05 | ND |
| 2018-03-05 | 8032061-06 | ND |
| 2018-03-05 | 8032061-07 | ND |
| 2018-03-05 | 8032061-08 | ND |
| 2018-03-05 | 8032061-09 | ND |
| 2018-03-05 | 8032061-01 | ND |
| 2019-02-05 | 9021904-01 | ND |
| 2020-02-04 | 21669190.00 | ND |
| 2021-02-04 | 23890621.00 | ND |
| 2021-03-01 | 24062455.00 | ND |
| 2021-03-01 | 24062456.00 | ND |
| 2021-03-01 | 24062460.00 | 1.000 ppb |
| 2021-03-01 | 24062457.00 | 1.000 ppb |
| 2021-03-01 | 24062458.00 | 1.000 ppb |
| 2021-03-01 | 24062459.00 | 1.000 ppb |
| 2021-03-01 | 24062454.00 | ND |
| 2022-02-01 | 26119361.00 | ND |
| 2023-02-07 | 28351349.00 | ND |