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 |
|---|---|---|---|---|
| 2018 | 0.726 ppb | 8 | 8 | 0.570 ppb - 0.870 ppb |
| 2019 | 0.788 ppb | 8 | 8 | 0.500 ppb - 1.11 ppb |
| 2020 | 0.679 ppb | 8 | 8 | 0.570 ppb - 0.800 ppb |
| 2021 | 0.864 ppb | 8 | 8 | 0.680 ppb - 1.34 ppb |
| 2022 | 0.790 ppb | 8 | 8 | 0.520 ppb - 1.04 ppb |
| 2023 | 0.900 ppb | 8 | 8 | 0.710 ppb - 1.18 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 |
|---|---|---|
| 2018-01-17 | 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-S1194 | 0.680 ppb |
| 2018-07-18 | 18-S1193 | 0.590 ppb |
| 2018-10-15 | 18-S2262 | 0.740 ppb |
| 2018-10-15 | 18-S2261 | 0.870 ppb |
| 2019-01-15 | 19-S45 | 0.610 ppb |
| 2019-01-15 | 19-S44 | 0.500 ppb |
| 2019-04-16 | 19-S436 | 0.800 ppb |
| 2019-04-16 | 19-S435 | 0.600 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 |
| 2020-01-13 | 360270 | 0.640 ppb |
| 2020-01-13 | 360269 | 0.660 ppb |
| 2020-04-13 | 363076 | 0.740 ppb |
| 2020-04-13 | 363075 | 0.640 ppb |
| 2020-07-21 | 368566 | 0.800 ppb |
| 2020-07-21 | 369616 | 0.570 ppb |
| 2020-10-13 | 372362 | 0.780 ppb |
| 2020-10-13 | 372361 | 0.600 ppb |
| 2021-01-12 | 375910 | 1.34 ppb |
| 2021-01-12 | 375909 | 0.740 ppb |
| 2021-04-13 | 378787 | 0.740 ppb |
| 2021-04-13 | 378786 | 0.740 ppb |
| 2021-07-20 | 383414 | 0.810 ppb |
| 2021-07-20 | 383413 | 0.680 ppb |
| 2021-10-11 | 389102 | 1.01 ppb |
| 2021-10-11 | 389101 | 0.850 ppb |
| 2022-01-11 | 391189 | 0.760 ppb |
| 2022-01-11 | 391192 | 0.820 ppb |
| 2022-04-11 | 394226 | 0.520 ppb |
| 2022-04-11 | 394225 | 0.530 ppb |
| 2022-07-19 | 398432 | 1.04 ppb |
| 2022-07-19 | 398434 | 1.01 ppb |
| 2022-10-04 | 402561 | 0.780 ppb |
| 2022-10-04 | 402560 | 0.860 ppb |
| 2023-01-10 | 405840 | 1.02 ppb |
| 2023-01-10 | 405841 | 1.18 ppb |
| 2023-04-19 | 410088 | 0.710 ppb |
| 2023-04-19 | 410089 | 0.870 ppb |
| 2023-07-25 | 415064 | 0.760 ppb |
| 2023-07-25 | 415063 | 0.990 ppb |
| 2023-10-10 | 418632 | 0.780 ppb |
| 2023-10-10 | 418633 | 0.890 ppb |