Chloroform
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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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 0.195 ppb | 4 | 2 | ND - 0.400 ppb |
2015 | 0.363 ppb | 3 | 2 | ND - 0.590 ppb |
2016 | 0.170 ppb | 3 | 1 | ND - 0.510 ppb |
2017 | 0.167 ppb | 3 | 1 | ND - 0.500 ppb |
2018 | ND | 4 | 0 | ND |
2019 | 0.263 ppb | 3 | 1 | ND - 0.790 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.4 ppb
The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.
ppb = parts per billion
All test results
Date | Lab ID | Result |
---|---|---|
2014-08-29 | 51342 | 0.400 ppb |
2014-08-29 | 51400 | 0.380 ppb |
2014-12-15 | 55830 | ND |
2014-12-15 | 55831 | ND |
2015-11-09 | 67948 | ND |
2015-11-30 | 68398 | 0.500 ppb |
2015-11-30 | 68393 | 0.590 ppb |
2016-06-06 | ND | |
2016-08-09 | 0.510 ppb | |
2016-09-07 | ND | |
2017-07-18 | ND | |
2017-08-21 | 0.500 ppb | |
2017-10-10 | ND | |
2018-04-10 | ND | |
2018-07-25 | ND | |
2018-08-08 | ND | |
2018-10-31 | ND | |
2019-04-08 | ND | |
2019-06-11 | ND | |
2019-08-05 | 0.790 ppb |