Diquat

Kalaheo-Koloa

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
2013	N/A	0	N/A
2014	N/A	0	N/A
2015	N/A	0	N/A
2016	N/A	0	N/A
2017	ND	1	ND
2018	ND	2	ND
2019	ND	24	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
2017-05-16		ND
2018-01-29	201801310036	ND
2018-01-29	201801000000	ND
2019-01-30	201901310193	ND
2019-03-20	201903220416	ND
2019-03-20	201903220488	ND
2019-03-20	201903220303	ND
2019-03-20	201903220415	ND
2019-03-20	201903220302	ND
2019-03-22	201903260283	ND
2019-03-22	201903260247	ND
2019-03-22	201903260250	ND
2019-03-22	201903260219	ND
2019-03-22	201903260218	ND
2019-06-18	201906200462	ND
2019-08-20	201908220600	ND
2019-08-20	201908220601	ND
2019-08-20	201908220544	ND
2019-08-20	201908220543	ND
2019-08-21	201908230494	ND
2019-08-21	201908230483	ND
2019-08-21	201908230361	ND
2019-08-21	201908230362	ND
2019-08-21	201908230493	ND
2019-08-21	201908230482	ND
2019-08-26	201908280583	ND
2019-10-15	201910170567	ND