Chloroform
City of Jamestown
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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.690 ppb | 14 | 13 | ND - 0.920 ppb |
| 2015 | 0.285 ppb | 8 | 4 | ND - 0.670 ppb |
| 2016 | 0.555 ppb | 8 | 7 | ND - 0.730 ppb |
| 2017 | 0.554 ppb | 8 | 7 | ND - 0.720 ppb |
| 2018 | 0.726 ppb | 8 | 8 | 0.570 ppb - 0.870 ppb |
| 2019 | 0.788 ppb | 8 | 8 | 0.500 ppb - 1.11 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 |
|---|---|---|
| 2014-01-21 | 14-S63 | 0.810 ppb |
| 2014-01-21 | 14-S62 | 0.680 ppb |
| 2014-01-21 | 14-S61 | 0.720 ppb |
| 2014-01-21 | 14-S60 | 0.790 ppb |
| 2014-04-22 | 14-S673 | 0.830 ppb |
| 2014-04-22 | 14-S671 | 0.740 ppb |
| 2014-04-22 | 14-S670 | 0.660 ppb |
| 2014-04-22 | 14-S672 | 0.670 ppb |
| 2014-07-21 | 14-S1645 | 0.920 ppb |
| 2014-07-21 | 14-S1643 | 0.760 ppb |
| 2014-07-21 | 14-S1642 | 0.740 ppb |
| 2014-07-21 | 14-S1644 | 0.750 ppb |
| 2014-10-21 | 14-S2671 | 0.590 ppb |
| 2014-10-22 | 14-S2670 | ND |
| 2015-01-21 | 15-S51 | 0.510 ppb |
| 2015-01-21 | 15-S50 | 0.510 ppb |
| 2015-04-21 | 15-S577 | 0.590 ppb |
| 2015-04-22 | 15-S576 | 0.670 ppb |
| 2015-07-20 | 15-S1316 | ND |
| 2015-07-20 | 15-S1312 | ND |
| 2015-10-19 | 15-S2367 | ND |
| 2015-10-19 | 15-S2368 | ND |
| 2016-01-19 | 16-S42 | 0.730 ppb |
| 2016-01-19 | 16-S43 | 0.710 ppb |
| 2016-04-19 | 16-S784 | 0.650 ppb |
| 2016-04-19 | 16-S785 | 0.670 ppb |
| 2016-07-18 | 16-S1630 | ND |
| 2016-07-18 | 16-S1629 | 0.540 ppb |
| 2016-10-18 | 16-S2683 | 0.600 ppb |
| 2016-10-18 | 16-S2684 | 0.540 ppb |
| 2017-01-17 | 17-S23 | 0.680 ppb |
| 2017-01-17 | 17-S22 | 0.700 ppb |
| 2017-04-17 | 17-S594 | 0.650 ppb |
| 2017-04-24 | 17-S621 | 0.540 ppb |
| 2017-07-24 | 17-S1289 | 0.540 ppb |
| 2017-07-24 | 17-S1288 | 0.600 ppb |
| 2017-10-16 | 17-S2301 | 0.720 ppb |
| 2017-10-16 | 17-S2302 | ND |
| 2018-01-17 | 18-S77 | 0.670 ppb |
| 2018-01-17 | 18-S78 | 0.570 ppb |
| 2018-04-16 | 18-S525 | 0.850 ppb |
| 2018-04-16 | 18-S524 | 0.840 ppb |
| 2018-07-18 | 18-S1193 | 0.590 ppb |
| 2018-07-18 | 18-S1194 | 0.680 ppb |
| 2018-10-15 | 18-S2262 | 0.740 ppb |
| 2018-10-15 | 18-S2261 | 0.870 ppb |
| 2019-01-15 | 19-S44 | 0.500 ppb |
| 2019-01-15 | 19-S45 | 0.610 ppb |
| 2019-04-16 | 19-S435 | 0.600 ppb |
| 2019-04-16 | 19-S436 | 0.800 ppb |
| 2019-07-15 | 19-S1129 | 0.680 ppb |
| 2019-07-15 | 19-S1128 | 0.930 ppb |
| 2019-10-14 | 19-S2322 | 1.11 ppb |
| 2019-10-14 | 19-S2323 | 1.07 ppb |