Cobalt
City of Mercer Island
NOTE: City of Mercer Island purchases water from Seattle Public Utilities which is required to test for cobalt. Sample information shown below was taken by Seattle Public Utilities.
Cobalt is a metal found throughout the environment; people may be exposed to cobalt in air, food and 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 |
|---|---|---|---|---|
| 2013 | ND | 8 | 0 | ND |
| 2014 | N/A | 0 | 0 | N/A |
| 2015 | ND | 16 | 0 | ND |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 70 ppb
The EWG Health Guideline of 70 ppb for cobalt was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against change in blood chemistry.
ppb = parts per billion
All test results
NOTE: City of Mercer Island purchases water from Seattle Public Utilities which is required to test for cobalt. Sample information shown below was taken by Seattle Public Utilities.
| Date | Lab ID | Result |
|---|---|---|
| 2015-01-13 | 201501140525AM | ND |
| 2015-01-13 | 201501140512AM | ND |
| 2015-01-13 | 201501140623AM | ND |
| 2015-01-13 | 201501140778AM | ND |
| 2015-04-06 | 201504070229AM | ND |
| 2015-04-06 | 201504070416AM | ND |
| 2015-04-06 | 201504070341AM | ND |
| 2015-04-06 | 201504070359AM | ND |
| 2015-07-22 | 201507230343AM | ND |
| 2015-07-22 | 201507230341AM | ND |
| 2015-07-22 | 201507230482AM | ND |
| 2015-07-22 | 201507230496AM | ND |
| 2015-10-13 | 201509280095AM | ND |
| 2015-10-13 | 201509280094AM | ND |
| 2015-10-13 | 201509280091AM | ND |
| 2015-10-13 | 201509280090AM | ND |