Chromium (total)
Mountain Water District #1 Marrow Bone
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.
14
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.156 ppb | 5 | 3 | ND - 0.270 ppb |
| 2015 | 0.200 ppb | 5 | 4 | ND - 0.320 ppb |
| 2016 | 1.000 ppb | 1 | 1 | 1.000 ppb |
| 2017 | ND | 1 | 0 | ND |
| 2018 | ND | 1 | 0 | ND |
| 2019 | ND | 1 | 0 | ND |
ppb = parts per billion
State and national drinking water standards and health guidelines
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 |
|---|---|---|
| 2014-04-16 | 201405316001 | ND |
| 2014-09-24 | 201410020495AM | ND |
| 2014-09-24 | 201410020497AM | 0.270 ppb |
| 2014-12-10 | 201412160719AM | 0.240 ppb |
| 2014-12-10 | 201412160721AM | 0.270 ppb |
| 2015-03-11 | 201503140125AM | 0.220 ppb |
| 2015-03-25 | 201503270363AM | 0.230 ppb |
| 2015-04-15 | 201504441001 | ND |
| 2015-06-17 | 201506230971AM | 0.230 ppb |
| 2015-06-17 | 201506230973AM | 0.320 ppb |
| 2016-04-13 | 201605178001 | 1.000 ppb |
| 2017-04-05 | 201704917001 | ND |
| 2018-04-19 | 201804541001 | ND |
| 2019-04-10 | 201904704001 | ND |