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EWG's Tap Water Database — 2021 UPDATE

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

North Wales Water Authority

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.

 

40

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND200ND
2015N/A00N/A
2016N/A00N/A
2017ND200ND
2018N/A00N/A
2019N/A00N/A

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
2014-04-0714030700-01ND
2014-04-0714030711-01ND
2014-04-0714030702-01ND
2014-04-0714030710-01ND
2014-04-0714030703-01ND
2014-04-0714030704-01ND
2014-04-0714030709-01ND
2014-04-0714030706-01ND
2014-04-0714030708-01ND
2014-04-0714030707-01ND
2014-07-147538078ND
2014-07-147538092ND
2014-07-147538090ND
2014-07-147538091ND
2014-07-147538088ND
2014-07-287553892ND
2014-07-287553889ND
2014-07-287553891ND
2014-07-287553890ND
2014-07-287552133ND
2017-04-0415939284ND
2017-04-1015939842ND
2017-04-1015939986ND
2017-04-1015939754ND
2017-04-1015939784ND
2017-04-1015939813ND
2017-04-1015939898ND
2017-04-1015939957ND
2017-04-1015939928ND
2017-05-2216258958ND
2017-07-0616415625ND
2017-07-2416567970ND
2017-07-2416568192ND
2017-07-2416567826ND
2017-07-2416567742ND
2017-07-2416567686ND
2017-07-2616567798ND
2017-07-2616567770ND
2017-07-2616567942ND
2017-07-2616567714ND