Chromium (total)
Twin Lakes Water Works Corporation
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 | 5.30 ppb | 1 | 1 | 5.30 ppb |
| 2019 | N/A | 0 | 0 | N/A |
| 2020 | 0.367 ppb | 3 | 1 | ND - 1.10 ppb |
| 2021 | 0.825 ppb | 4 | 3 | ND - 1.20 ppb |
| 2022 | 1.15 ppb | 2 | 2 | 1.10 ppb - 1.20 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 |
|---|---|---|
| 2018-02-22 | AU03751-INP | 5.30 ppb |
| 2020-06-02 | AW10200-INP | 1.10 ppb |
| 2020-06-02 | AW10202-INP | ND |
| 2020-10-14 | AW19900-INP | ND |
| 2021-05-21 | CI37078-INP | ND |
| 2021-06-09 | AX11168-INP | 1.10 ppb |
| 2021-06-09 | AX11166-INP | 1.000 ppb |
| 2021-10-06 | AX20390-INP | 1.20 ppb |
| 2022-06-07 | AY09590-INP | 1.10 ppb |
| 2022-10-04 | AY17875-INP | 1.20 ppb |
| 2023-03-20 | AZ04882-INP | ND |
| 2023-05-10 | AZ08444-INP-1 | ND |
| 2023-05-10 | AZ08442-INP | ND |
| 2023-12-13 | AZ22568-INP | ND |