Chromium (total)

City of Laredo

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.

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Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	0.0723 ppb	6	2	ND - 0.220 ppb
2014	ND	1	0	ND
2015	ND	5	0	ND
2016	ND	5	0	ND
2017	ND	5	0	ND
2018	ND	5	0	ND
2019	ND	5	0	ND

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
2013-05-21	Q1301326003	ND
2013-05-21	Q1301326001	ND
2013-08-20	Q1305820003	0.214 ppb
2013-08-20	Q1305820001	0.220 ppb
2013-11-18	Q1313650003	ND
2013-11-18	Q1313650001	ND
2014-02-19	AC43511	ND
2015-03-16	AC84345	ND
2015-11-17	AD13753	ND
2015-11-18	AD13972	ND
2015-11-18	AD13971	ND
2015-12-14	AD16711	ND
2016-02-16	AD23582	ND
2016-06-20	AD41291	ND
2016-06-20	AD41290	ND
2016-07-21	AD45134	ND
2016-07-21	AD45137	ND
2017-02-21	AD71199	ND
2017-02-21	AD71206	ND
2017-09-05	AD94689	ND
2017-09-05	AD94690	ND
2017-12-05	AE06723	ND
2018-03-05	AE16575	ND
2018-07-16	AE33485	ND
2018-10-16	AE43559	ND
2018-10-16	AE43558	ND
2018-10-16	AE43560	ND
2019-03-11	AE57783	ND
2019-03-11	AE57784	ND
2019-06-06	AE69376	ND
2019-08-20	AE79751	ND
2019-08-20	AE79750	ND