Diquat
City of Beaverton
NOTE: City of Beaverton purchases water from Joint Water Commission which is required to test for diquat. Sample information shown below was taken by Joint Water Commission.
Diquat is a herbicide used on potato crops and aquatic weeds.
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 | 2 | 0 | ND |
| 2023 | ND | 3 | 0 | ND |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
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
NOTE: City of Beaverton purchases water from Joint Water Commission which is required to test for diquat. Sample information shown below was taken by Joint Water Commission.
| Date | Lab ID | Result |
|---|---|---|
| 2018-02-07 | 1809141-S | ND |
| 2018-11-05 | 1884309-S | ND |
| 2019-04-24 | 1928990-S | ND |
| 2019-11-04 | 1981259-S | ND |
| 2020-04-01 | 2021410-S | ND |
| 2020-07-01 | 2041305-S | ND |
| 2020-11-04 | 2074464-S | ND |
| 2021-04-07 | 2123196-S | ND |
| 2021-11-03 | 2180746-S | ND |
| 2022-03-31 | 2221620-S | ND |
| 2022-11-02 | 22-71086-S | ND |
| 2023-04-10 | 23-19659-S | ND |
| 2023-11-06 | 23-67462-S | ND |