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EWG's Tap Water Database — 2021 UPDATE

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2,3,7,8-TCDD (Dioxin)

Montara Water and Sanitary District

Dioxins are contaminants released from chemical manufacturing, pulp and paper bleaching, and incineration of products that contain chlorine. 2,3,7,8-Tetrachlorodibenzodioxin (2,3,7,8-TCDD) is the most toxic chemical in the group of dioxins. Read More.

Dioxins are among the most toxic known environmental pollutants. As a class, dioxins are extremely toxic, persistent and bioaccumulative; these contaminants build up and are stored in fatty tissues and fluids, such as breast milk, and pass from the mother to the child. Most people are exposed to dioxins through the food they eat, primarily from meat, dairy, fish and eggs. In humans, dioxins are associated with cancer, birth defects, damage to the nervous and immune systems, altered metabolism, thyroid disruption, altered menstrual cycling and damage to the cardiovascular system.

 

36

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015ND90ND
2016ND90ND
2017ND50ND
2018ND70ND
2019ND60ND

ppt = parts per trillion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.0002 ppt

The EWG Health Guideline of 0.0002 ppt for 2,3,7,8-TCDD was defined by the Environmental Protection Agency as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

EPA Maximum Contaminant
Level (MCL) 0.03 ppt

ppt = parts per trillion

All test results

Date Lab ID Result
2015-10-192116-032-1015ND
2015-10-192116-031-1050ND
2015-11-090013-001-1130ND
2015-11-090013-014-1150ND
2015-11-090013-012-1120ND
2015-11-090013-010-1140ND
2015-11-230013-003-1020ND
2015-11-230013-015-1125ND
2015-11-230013-008-1345ND
2016-01-280013-011-0930ND
2016-03-100013-011-1125ND
2016-03-140013-001-0840ND
2016-03-140013-015-0850ND
2016-03-140013-014-0905ND
2016-03-140013-012-0822ND
2016-03-140013-010-0845ND
2016-03-140013-008-0935ND
2016-03-140013-003-0855ND
2017-07-201228-001-0930ND
2017-07-201228-003-1120ND
2017-11-081228-003-0940ND
2017-11-081228-014-0920ND
2017-11-081228-001-1105ND
2018-02-081228-014-0845ND
2018-11-131228-015-0840ND
2018-11-151228-032-0835ND
2018-11-151228-031-0815ND
2018-11-151228-030-0900ND
2018-12-211228-010-1310ND
2018-12-211228-008-1300ND
2019-02-121228-015-0935ND
2019-02-191228-030-0940ND
2019-02-191228-031-0910ND
2019-02-191228-008-1115ND
2019-02-191228-010-1045ND
2019-02-191228-032-1000ND