Chromium (total)
Tryon Road Special Utility District
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 | 1 | 0 | ND |
| 2019 | ND | 1 | 0 | ND |
| 2020 | ND | 2 | 0 | ND |
| 2021 | ND | 1 | 0 | ND |
| 2022 | ND | 1 | 0 | ND |
| 2023 | 1.25 ppb | 2 | 1 | ND - 2.50 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 |
|---|---|---|
| 2019-03-21 | Q1911930006 | ND |
| 2020-05-26 | Q2020608021 | ND |
| 2020-05-26 | Q2020608022 | ND |
| 2022-10-24 | Q2231972008 | ND |
| 2023-07-19 | Q2328456004 | ND |
| 2023-08-10 | Q2333267007 | 2.50 ppb |