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EWG's Tap Water Database — 2019 UPDATE

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Chromium (total)

Contra Costa Water District

Chromium is a naturally occurring metal, but industrial uses can elevate its levels in water. One form, hexavalent chromium, causes cancer. Total chromium is not a good indicator of the amount of hexavalent chromium in drinking water.

 

20

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND10ND
20130.108 ppb134ND - 0.500 ppb
2014ND20ND
2015ND10ND
2016ND10ND
2017ND20ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 100 ppb

The legal limit for total chromium, established in 1991, was based on a 1958 toxicity study in laboratory animals, and applies to both the less-toxic trivalent chromium and the more-toxic hexavalent chromium forms of this compound. This limit does not protect against the risk of cancer from ingestion of hexavalent chromium.

ppb = parts per billion

All test results

Date Lab ID Result
2012-07-092473-003-0800ND
2013-03-12201303130365AM0.500 ppb
2013-03-12201303130386AM0.400 ppb
2013-03-20201303210135AM0.240 ppb
2013-06-11201306120211AMND
2013-06-12201306130200AMND
2013-06-12201306130196AM0.270 ppb
2013-07-159590-003-1345ND
2013-09-10201309110439AMND
2013-09-11201309120291AMND
2013-09-11201309120475AMND
2013-12-10201312120835AMND
2013-12-11201312120652AMND
2013-12-11201312120837AMND
2014-07-079590-003-1455ND
2014-07-219590-019-1330ND
2015-07-069590-003-0815ND
2016-07-119590-003-1350ND
2017-07-109590-003-1450ND
2017-12-199590-003-1330ND