Chloroform
Saint Louis Park
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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.430 ppb | 9 | 8 | ND - 1.20 ppb |
| 2015 | 0.585 ppb | 6 | 6 | 0.330 ppb - 1.50 ppb |
| 2016 | 0.280 ppb | 18 | 11 | ND - 0.800 ppb |
| 2017 | 0.166 ppb | 15 | 7 | ND - 0.800 ppb |
| 2018 | 0.764 ppb | 7 | 7 | 0.230 ppb - 1.30 ppb |
| 2019 | 0.481 ppb | 8 | 7 | ND - 1.000 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 |
|---|---|---|
| 2014-03-19 | 14C0829-02 | ND |
| 2014-03-19 | 14C0829-01 | 0.240 ppb |
| 2014-05-29 | 14E3054-02 | 0.610 ppb |
| 2014-05-29 | 14E3056-01 | 0.350 ppb |
| 2014-05-29 | 14E3054-01 | 0.270 ppb |
| 2014-08-25 | 14H2269-01 | 0.500 ppb |
| 2014-08-25 | 14H2269-02 | 1.20 ppb |
| 2014-08-26 | 14H2350-01 | 0.390 ppb |
| 2014-12-17 | 14L0719-01 | 0.310 ppb |
| 2015-03-30 | 15C1168-01 | 0.340 ppb |
| 2015-06-10 | 15F0705-01 | 0.410 ppb |
| 2015-08-03 | 15H0096-01 | 0.600 ppb |
| 2015-08-03 | 15H0096-02 | 1.50 ppb |
| 2015-09-24 | 15I1305-01 | 0.330 ppb |
| 2015-11-19 | 15K1031-01 | 0.330 ppb |
| 2016-01-14 | 16A0523-02 | 0.130 ppb |
| 2016-01-14 | 16A0523-01 | ND |
| 2016-01-14 | 16A0522-01 | 0.340 ppb |
| 2016-02-17 | 16B0917-01 | 0.250 ppb |
| 2016-02-17 | 16B0917-02 | 0.640 ppb |
| 2016-02-17 | 16B0917-03 | ND |
| 2016-02-17 | 16B0917-04 | 0.720 ppb |
| 2016-06-01 | 16F0030-01 | 0.260 ppb |
| 2016-06-01 | 16F0032-01 | ND |
| 2016-08-23 | 16H2430-01 | 0.700 ppb |
| 2016-08-23 | 16H2430-02 | 0.800 ppb |
| 2016-08-25 | 16H2589-01 | 0.120 ppb |
| 2016-08-25 | 16H2590-01 | 0.580 ppb |
| 2016-08-25 | 16H2593-01 | ND |
| 2016-11-08 | 16K0369-01 | 0.500 ppb |
| 2016-11-08 | 16K0370-01 | ND |
| 2016-12-05 | 16L0214-01 | ND |
| 2016-12-05 | 16L0214-02 | ND |
| 2017-01-05 | 17A0039-01 | ND |
| 2017-01-05 | 17A0039-02 | ND |
| 2017-01-05 | 17A0040-01 | 0.240 ppb |
| 2017-04-11 | 17D0599-01 | 0.330 ppb |
| 2017-08-01 | 17H0064-01 | 0.280 ppb |
| 2017-08-01 | 17H0064-02 | ND |
| 2017-08-01 | 17H0064-03 | ND |
| 2017-08-14 | 17H1171-01 | ND |
| 2017-08-14 | 17H1171-02 | 0.800 ppb |
| 2017-11-01 | 17K0062-02 | ND |
| 2017-11-01 | 17K0062-01 | ND |
| 2017-11-01 | 17K0061-01 | ND |
| 2017-11-01 | 17K0059-04 | 0.230 ppb |
| 2017-11-01 | 17K0059-01 | 0.130 ppb |
| 2017-11-01 | 17K0060-01 | 0.480 ppb |
| 2018-01-19 | 18A0639-01 | 0.710 ppb |
| 2018-04-10 | 18D0389-01 | 0.230 ppb |
| 2018-07-12 | 18G0516-01 | 0.520 ppb |
| 2018-07-12 | 18G0518-01 | 0.990 ppb |
| 2018-08-07 | 18H0579-01 | 1.000 ppb |
| 2018-08-07 | 18H0579-02 | 0.600 ppb |
| 2018-10-17 | 18J0842-01 | 1.30 ppb |
| 2019-02-13 | 19B0557-01 | 0.450 ppb |
| 2019-05-16 | 19E1269-01 | ND |
| 2019-05-16 | 19E1270-01 | 0.150 ppb |
| 2019-05-21 | 19E1637-01 | 0.510 ppb |
| 2019-08-07 | 19H0616-01 | 0.820 ppb |
| 2019-08-14 | 19H1358-01 | 0.700 ppb |
| 2019-08-14 | 19H1358-02 | 1.000 ppb |
| 2019-10-29 | 19J1574-01 | 0.220 ppb |