Diquat
City of Safford
Diquat is a herbicide used on potato crops and aquatic weeds.
30
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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | ND | 10 | 0 | ND |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | 0.0350 ppb | 16 | 1 | ND - 0.560 ppb |
| 2018 | ND | 4 | 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 |
|---|---|---|
| 2014-05-20 | 550-24920-9S | ND |
| 2014-05-20 | 550-24920-7S | ND |
| 2014-05-20 | 550-24920-5S | ND |
| 2014-05-20 | 550-24920-3S | ND |
| 2014-05-20 | 550-24920-1S | ND |
| 2014-10-14 | 550-33356-9 | ND |
| 2014-10-14 | 550-33356-7 | ND |
| 2014-10-14 | 550-33356-5 | ND |
| 2014-10-14 | 550-33356-3 | ND |
| 2014-10-14 | 550-33356-1 | ND |
| 2017-02-08 | 550-77226-1S | ND |
| 2017-02-08 | 550-77231-1S | ND |
| 2017-02-08 | 550-77229-1S | ND |
| 2017-02-08 | 550-77228-1S | ND |
| 2017-02-08 | 550-77227-1S | ND |
| 2017-02-08 | 550-77225-1S | ND |
| 2017-03-13 | 550-79141-1 | ND |
| 2017-06-05 | 550-83847-1 | ND |
| 2017-08-30 | 550-89048-1SOC | ND |
| 2017-09-28 | 550-90609-1SOC | ND |
| 2017-09-28 | 550-90605-1SOC | ND |
| 2017-10-09 | 550-91194-1SOC | 0.560 ppb |
| 2017-10-09 | 550-91192-1SOC | ND |
| 2017-10-09 | 550-91187-1SOC | ND |
| 2017-11-02 | 550-92615-1 | ND |
| 2017-11-13 | 550-93144-1 | ND |
| 2018-02-21 | 550-98383-1SOC | ND |
| 2018-05-16 | 550-103092-1 SOC | ND |
| 2018-08-01 | 550-107260-1 | ND |
| 2018-11-19 | 550-113702-1 | ND |