Diquat
City of Lewiston
Diquat is a herbicide used on potato crops and aquatic weeds.
23
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 |
|---|---|---|---|---|
| 2018 | ND | 4 | 0 | ND |
| 2019 | ND | 4 | 0 | ND |
| 2020 | ND | 6 | 0 | ND |
| 2021 | ND | 5 | 0 | ND |
| 2022 | ND | 3 | 0 | ND |
| 2023 | ND | 1 | 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
| Date | Lab ID | Result |
|---|---|---|
| 2018-02-21 | S180221045-001 | ND |
| 2018-02-22 | S180223004-001 | ND |
| 2018-12-13 | S181213011-002 | ND |
| 2018-12-13 | S181213011-001 | ND |
| 2019-01-24 | S190124017-001 | ND |
| 2019-04-23 | S190423067-001 | ND |
| 2019-04-23 | S190423067-002 | ND |
| 2019-08-14 | S190814080-001 | ND |
| 2020-02-19 | S200219035-001 | ND |
| 2020-07-28 | SMAG0811-08 | ND |
| 2020-07-28 | SMAG0811-07 | ND |
| 2020-07-28 | SMAG0811-05 | ND |
| 2020-07-28 | SMAG0811-03 | ND |
| 2020-07-28 | SMAG0811-01 | ND |
| 2021-06-29 | SMBF0852-03 | ND |
| 2021-06-29 | SMBF0852-01 | ND |
| 2021-06-29 | SMBF0852-07 | ND |
| 2021-06-29 | SMBF0852-06 | ND |
| 2021-06-29 | SMBF0852-04 | ND |
| 2022-06-28 | SMCF0954-01 | ND |
| 2022-09-21 | SMCI0682-01 | ND |
| 2022-11-21 | SMCK0693-01 | ND |
| 2023-01-18 | SMDA0450-01 | ND |