2,4-D

Regional Water Authority

2,4-D (2,4-dichlorophenoxyacetic acid) is a herbicide that can be applied directly to GMO corn and soy plants engineered to withstand this toxic chemical. Americans' exposures to 2,4-D from food and drinking water will likely increase in years to come as farmers plant more of these GMO crops. Read More.

2,4-D is an endocrine disruptor that interferes with thyroid hormones. The International Agency for Research on Cancer classifies 2,4-D as possibly carcinogenic to humans. In occupational studies, farmers exposed to 2,4-D tended to have higher incidences of damaged and malformed sperm. Laboratory animals exposed to 2,4-D during gestation are born underdeveloped and are more likely to have birth defects.

MORE ABOUT THIS CONTAMINANT

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	4	ND
2015	ND	5	ND
2016	ND	23	ND
2017	ND	4	ND
2018	ND	4	ND
2019	ND	26	ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 20 ppb

The EWG Health Guideline of 20 ppb for 2,4-D 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 harm to internal organs.

EPA Maximum Contaminant
Level (MCL) 70 ppb

The legal limit for 2,4-D, established in 1991, was based on toxicity studies in laboratory animals conducted in the 1980s. This limit may not fully protect against harm to the nervous system, harm to the thyroid, and hormone disruption.

ppb = parts per billion

All test results

Date	Lab ID	Result
2014-12-09	SOCR 200409186	ND
2014-12-09	SOCR 200409185	ND
2014-12-09	SOCR 200409203	ND
2014-12-09	SOCR 200409202	ND
2015-03-03	SOCR 200412990	ND
2015-03-03	SOCR 200412991	ND
2015-03-03	SOCR 200412906	ND
2015-03-04	SOCR 200413024	ND
2015-06-25	SOC 200419193	ND
2016-02-29	SOCR 200434389	ND
2016-02-29	SOCR 200434374	ND
2016-02-29	SOCR 200434388	ND
2016-02-29	SOCR 200434373	ND
2016-05-16	SOC 200439620	ND
2016-05-16	SOC 200439628	ND
2016-05-16	SOC 200439627	ND
2016-05-16	SOC 200439619	ND
2016-05-16	SOC 200439623	ND
2016-05-16	SOC 200439625	ND
2016-05-16	SOC 200439626	ND
2016-05-16	SOC 200439622	ND
2016-08-29	SOC 200448465	ND
2016-08-29	SOC 200448473	ND
2016-08-29	SOC 200448472	ND
2016-08-29	SOC 200448466	ND
2016-08-29	SOC 200448468	ND
2016-08-29	SOC 200448469	ND
2016-08-29	SOC 200448470	ND
2016-08-29	SOC 200448471	ND
2016-08-30	SOC 200448554	ND
2016-09-28	SOC 200451204	ND
2016-11-22	SOC 200455270	ND
2017-02-27	SOCR 200461303	ND
2017-02-27	SOCR 200461318	ND
2017-02-27	SOCR 200461319	ND
2017-06-22	SOCR 200470146	ND
2018-03-05	SOCR 200489131	ND
2018-03-05	SOCR 200489130	ND
2018-03-05	SOCR 200489152	ND
2018-11-29	SOCR 200514127	ND
2019-03-04	SOCR 200523153	ND
2019-03-04	SOCR 200523178	ND
2019-03-04	SOCR 200523152	ND
2019-03-04	SOCR 200523177	ND
2019-05-08	SOC 200531300	ND
2019-05-28	SOC 200533659	ND
2019-05-28	SOC 200533660	ND
2019-05-28	SOC 200533804	ND
2019-05-28	SOC 200533719	ND
2019-05-28	SOC 200533720	ND
2019-05-28	SOC 200533803	ND
2019-05-29	SOC 200533881	ND
2019-05-29	SOC 200533880	ND
2019-05-29	SOC 200533867	ND
2019-05-29	SOC 200533868	ND
2019-08-26	SOC 200546200	ND
2019-08-26	SOC 200546198	ND
2019-08-26	SOC 200546197	ND
2019-08-27	SOC 200546267	ND
2019-08-27	SOC 200546268	ND
2019-08-27	SOC 200546302	ND
2019-08-27	SOC 200546303	ND
2019-08-28	SOC 200546738	ND
2019-08-28	SOC 200546737	ND
2019-08-28	SOC 200546736	ND
2019-08-28	SOC 200546553	ND