trans-1,2-Dichloroethylene
San Francisco Regional Water System
1,2-Dichloroethylene, a neurotoxic solvent, exists in two different forms: trans-1,2-dichloroethylene and cis-1,2-dichloroethylene. A mixture of the two forms is used to manufacture other solvents and chemical products.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2012 | ND | 1 | 0 | ND |
| 2013 | ND | 3 | 0 | ND |
| 2014 | ND | 2 | 0 | ND |
| 2015 | ND | 2 | 0 | ND |
| 2016 | ND | 3 | 0 | ND |
| 2017 | ND | 3 | 0 | ND |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 60 ppb
The EWG Health Guideline of 60 ppb for trans-1,2-dichloroethylene was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against harm to internal organs.
EPA Maximum Contaminant
Level (MCL) 100 ppb
The legal limit for trans-1,2-dichloroethylene, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1980s.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2012-06-13 | 9590-001-1045 | ND |
| 2013-06-18 | 9553-016-0936 | ND |
| 2013-06-18 | 9553-001-1110 | ND |
| 2013-10-07 | 9553-015-1024 | ND |
| 2014-06-17 | 9553-016-0904 | ND |
| 2014-06-17 | 9553-001-1130 | ND |
| 2015-05-27 | 9553-001-1235 | ND |
| 2015-06-18 | 9553-015-0915 | ND |
| 2016-06-14 | 9553-015-1231 | ND |
| 2016-06-14 | 9553-001-1105 | ND |
| 2016-06-21 | 9553-016-1055 | ND |
| 2017-06-19 | 9553-015-1100 | ND |
| 2017-06-19 | 9553-001-1025 | ND |
| 2017-06-19 | 9553-016-0953 | ND |