Diquat

Ozark Utilities Board

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	Range of results
2014	ND	3	ND
2015	N/A	0	N/A
2016	ND	16	ND
2017	N/A	0	N/A
2018	N/A	0	N/A
2019	ND	16	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
2014-04-17	AC89206	ND
2014-04-17	AC89207	ND
2014-04-17	AC89208	ND
2016-02-18	AB10061	ND
2016-02-18	AB10063	ND
2016-02-18	AB10071	ND
2016-02-18	AB10067	ND
2016-06-13	AB12393	ND
2016-06-13	AB12394	ND
2016-06-13	AB12396	ND
2016-06-13	AB12395	ND
2016-08-03	AB14008	ND
2016-08-03	AB14009	ND
2016-08-03	AB14010	ND
2016-08-03	AB14011	ND
2016-12-27	AB17042	ND
2016-12-27	AB17041	ND
2016-12-27	AB17040	ND
2016-12-27	AB17039	ND
2019-02-07	AB32886	ND
2019-02-07	AB32887	ND
2019-02-07	AB32885	ND
2019-02-07	AB32884	ND
2019-06-19	AB36109	ND
2019-06-19	AB36110	ND
2019-06-19	AB36108	ND
2019-06-19	AB36107	ND
2019-08-27	AB37953	ND
2019-08-27	AB37952	ND
2019-08-27	AB37951	ND
2019-08-27	AB37950	ND
2019-11-21	AB40300	ND
2019-11-21	AB40299	ND
2019-11-21	AB40298	ND
2019-11-21	AB40297	ND