Diquat
San Francisco City Water System
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 |
---|---|---|---|---|
2013 | N/A | 0 | 0 | N/A |
2014 | N/A | 0 | 0 | N/A |
2015 | N/A | 0 | 0 | N/A |
2016 | N/A | 0 | 0 | N/A |
2017 | N/A | 0 | 0 | N/A |
2018 | ND | 16 | 0 | ND |
2019 | N/A | 0 | 0 | N/A |
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 |
---|---|---|
2018-01-11 | 9590-007-1115 | ND |
2018-03-06 | 9590-004-1031 | ND |
2018-03-06 | 9590-008-0914 | ND |
2018-03-08 | 9590-006-0925 | ND |
2018-04-17 | 9590-007-1055 | ND |
2018-06-12 | 9590-004-1058 | ND |
2018-06-12 | 9590-006-1012 | ND |
2018-06-12 | 9590-008-0930 | ND |
2018-07-17 | 9590-007-0519 | ND |
2018-09-18 | 9590-004-0855 | ND |
2018-09-18 | 9590-006-0945 | ND |
2018-09-18 | 9590-008-1025 | ND |
2018-10-17 | 9590-007-0730 | ND |
2018-12-11 | 9590-004-0845 | ND |
2018-12-11 | 9590-006-0915 | ND |
2018-12-11 | 9590-008-1045 | ND |