Diquat
Guilford Water Authority
Diquat is a herbicide used on potato crops and aquatic weeds.
16
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 |
|---|---|---|---|---|
| 2014 | ND | 4 | 0 | ND |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | ND | 8 | 0 | ND |
| 2018 | ND | 3 | 0 | ND |
| 2019 | ND | 1 | 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 |
|---|---|---|
| 2014-06-16 | 14062126-001 | ND |
| 2014-06-16 | 14062126-003 | ND |
| 2014-09-12 | 14091536-001 | ND |
| 2014-09-12 | 14091536-003 | ND |
| 2017-04-17 | 16214716 | ND |
| 2017-04-17 | 16052893 | ND |
| 2017-04-17 | 16214680 | ND |
| 2017-04-17 | 16052857 | ND |
| 2017-07-21 | 16686267 | ND |
| 2017-07-21 | 16526351 | ND |
| 2017-07-21 | 16686303 | ND |
| 2017-07-21 | 16526387 | ND |
| 2018-05-29 | 8055384-01 | ND |
| 2018-09-04 | 8091925-01 | ND |
| 2018-12-11 | 8122846-01 | ND |
| 2019-03-05 | 9032320-01 | ND |