Chromium (total)
Groton Utilities
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 | ND | 2 | 0 | ND |
| 2021 | ND | 2 | 0 | ND |
| 2022 | ND | 3 | 0 | ND |
| 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 |
|---|---|---|
| 2018-11-29 | 28467IOCR | ND |
| 2018-11-29 | 28430IOC1 | ND |
| 2019-11-20 | 30564IOCR | ND |
| 2019-11-20 | 30566IOC1 | ND |
| 2020-12-01 | 32781IOCR | ND |
| 2020-12-01 | 32783IOC1 | ND |
| 2021-10-27 | 34806IOCR | ND |
| 2021-10-27 | 34812IOC1 | ND |
| 2022-09-15 | 36588IOCR | ND |
| 2022-09-15 | 36587IOCR | ND |
| 2022-09-15 | 37093IOC1 | ND |
| 2023-09-14 | 38748IOCR | ND |
| 2023-09-14 | 38742IOC1 | ND |