Diquat
City of Caldwell
Diquat is a herbicide used on potato crops and aquatic weeds.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | ND | 4 | 0 | ND |
2015 | ND | 3 | 0 | ND |
2016 | ND | 5 | 0 | ND |
2017 | N/A | 0 | 0 | N/A |
2018 | N/A | 0 | 0 | N/A |
2019 | ND | 9 | 0 | ND |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 6 ppb
The EWG Health Guideline of 6 ppb for diquat was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cataracts.
EPA Maximum Contaminant
Level (MCL) 20 ppb
The legal limit for diquat, established in 1992, was based on a toxicity study in laboratory animals conducted in the 1980s.
ppb = parts per billion
All test results
Date | Lab ID | Result |
---|---|---|
2014-02-26 | S1407039 | ND |
2014-06-18 | S1422594 | ND |
2014-09-29 | S1438512 | ND |
2014-11-13 | S1445335 | ND |
2015-03-10 | S1509143 | ND |
2015-05-06 | S1517379 | ND |
2015-09-24 | S1541055 | ND |
2016-09-06 | S1640377 | ND |
2016-09-06 | S1640374 | ND |
2016-09-06 | S1640375 | ND |
2016-09-06 | S1640376 | ND |
2016-09-06 | S1640378 | ND |
2019-08-06 | S1938593 | ND |
2019-08-06 | S1938591 | ND |
2019-08-06 | S1938594 | ND |
2019-08-06 | S1938601 | ND |
2019-08-06 | S1938599 | ND |
2019-08-06 | S1938597 | ND |
2019-08-19 | S1941179 | ND |
2019-08-19 | S1941172 | ND |
2019-08-19 | S1941181 | ND |