Know Your Environment. Protect Your Health.

Hexachlorocyclopentadiene

St John Water District 1

Hexachlorocyclopentadiene was historically used for the manufacture of currently banned pesticides, such as endrin, dieldrin and chlordane. It’s still used for production of flame retardants, resins and plastics.

 

15

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND40ND
2019ND40ND
2020ND10ND
2021ND20ND
2022ND20ND
20230.0425 ppb21ND - 0.0850 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 2 ppb

The EWG Health Guideline of 2 ppb for hexachlorocyclopentadiene 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 stomach and intestines.

EPA Maximum Contaminant
Level (MCL): 50 ppb

The legal limit for hexachlorocyclopentadiene, established in 1992, was based on a toxicity study in laboratory animals conducted in the 1980s.

ppb = parts per billion

All test results

Date Lab ID Result
2018-05-1435392327001ND
2018-05-1435392327001ND
2018-07-1735405084001ND
2018-07-1735405084001ND
2019-01-2235444040001ND
2019-01-2235444040001ND
2019-07-2535485228001ND
2019-07-2535485228001ND
2020-10-2235587106001ND
2021-01-2835608068001ND
2021-11-1835679380001ND
2022-02-0235694871001ND
2022-09-1535747517001ND
2023-03-20357876030010.0850 ppb
2023-11-2835844327001ND