Know Your Environment. Protect Your Health.

Cyanide

Harris County Fresh Water Supply District 1a

Cyanide is a toxic chemical that causes central nervous system and thyroid toxicity. Water contamination is generally the result of metal mining and chemical industry waste, runoff from agriculture and road salts used for melting ice.

 

23

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20185.00 ppb41ND - 20.0 ppb
2019ND40ND
2020ND40ND
2021ND40ND
2022ND40ND
202343.3 ppb32ND - 120.0 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 150 ppb

The EWG Health Guideline of 150 ppb for cyanide 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 the brain and nervous system.

EPA Maximum Contaminant
Level (MCL): 200 ppb

The legal limit for cyanide, established in 1992, was based on a 1955 toxicity study conducted in laboratory animals. This limit does not include any additional consideration of children’s health.

ppb = parts per billion

All test results

Date Lab ID Result
2018-01-24AE1008120.0 ppb
2018-04-11AE21974ND
2018-08-03AE35754ND
2018-11-27AE46939ND
2019-01-11AE49477ND
2019-04-05AE61284ND
2019-07-18AE74956ND
2019-11-19AE89714ND
2020-01-21AE94243ND
2020-04-15AF06779ND
2020-07-22AF20175ND
2020-10-26AF32039ND
2021-03-08AF45591ND
2021-05-26AF55498ND
2021-08-02AF64170ND
2021-10-14AF73486ND
2022-01-31AF82445ND
2022-04-25AF94155ND
2022-09-30AG15617ND
2022-10-03AG15619ND
2023-06-14AG4442510.00 ppb
2023-07-25AG49938ND
2023-11-27AG64355120.0 ppb