Know Your Environment. Protect Your Health.

Chloroform

City of Dorchester

Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.

In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.

Click here to read more about disinfection byproducts.

 

18

Samples

0

Samples exceeding legal limit (MCL)

10

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20182.22 ppb32ND - 3.76 ppb
20194.02 ppb32ND - 10.2 ppb
20201.29 ppb32ND - 2.86 ppb
20211.19 ppb31ND - 3.58 ppb
20220.867 ppb32ND - 1.54 ppb
20230.723 ppb31ND - 2.17 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.

ppb = parts per billion

All test results

Date Lab ID Result
2018-07-05Q18266280093.76 ppb
2018-07-05Q1826628010ND
2018-07-05Q18266280012.89 ppb
2019-08-13Q195423500210.2 ppb
2019-08-13Q1954235004ND
2019-08-13Q19542350101.87 ppb
2020-09-15Q20365410021.02 ppb
2020-10-15Q2040499003ND
2020-11-23Q20464500012.86 ppb
2021-09-20Q21255980033.58 ppb
2021-09-20Q2125598009ND
2021-12-13Q2134947004ND
2022-06-29Q2218370001ND
2022-06-29Q22183700061.06 ppb
2022-10-19Q22318290031.54 ppb
2023-05-23Q2319370002ND
2023-08-23Q2335730001ND
2023-11-13Q23484300012.17 ppb