Chromium (total)
Cross Timbers Water Supply 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 | ND | 2 | 0 | ND |
| 2019 | 0.240 ppb | 5 | 1 | ND - 1.20 ppb |
| 2020 | 0.850 ppb | 2 | 1 | ND - 1.70 ppb |
| 2021 | ND | 2 | 0 | ND |
| 2022 | 1.12 ppb | 6 | 2 | ND - 5.40 ppb |
| 2023 | 2.80 ppb | 1 | 1 | 2.80 ppb |
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 |
|---|---|---|
| 2019-03-07 | Q1909909004 | ND |
| 2019-03-07 | Q1909909009 | 1.20 ppb |
| 2019-06-05 | Q1932306007 | ND |
| 2019-06-05 | Q1932306008 | ND |
| 2019-06-05 | Q1932306009 | ND |
| 2022-02-17 | Q2205965002 | 1.30 ppb |
| 2022-02-17 | Q2205965003 | 5.40 ppb |
| 2022-09-22 | Q2228542004 | ND |
| 2022-11-29 | Q2235312008 | ND |
| 2022-11-29 | Q2235312009 | ND |
| 2022-11-29 | Q2235312010 | ND |
| 2023-03-02 | Q2308488013 | 2.80 ppb |