trans-1,2-Dichloroethylene
Twin Buttes Water System
NOTE: Twin Buttes Water System purchases water from City of San Angelo which is required to test for trans-1,2-dichloroethylene. Sample information shown below was taken by City of San Angelo.
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 |
|---|---|---|---|---|
| 2014 | ND | 9 | 0 | ND |
| 2015 | ND | 1 | 0 | ND |
| 2016 | ND | 2 | 0 | ND |
| 2017 | ND | 1 | 0 | ND |
| 2018 | ND | 1 | 0 | ND |
| 2019 | ND | 1 | 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
NOTE: Twin Buttes Water System purchases water from City of San Angelo which is required to test for trans-1,2-dichloroethylene. Sample information shown below was taken by City of San Angelo.
| Date | Lab ID | Result |
|---|---|---|
| 2014-04-29 | AC52069 | ND |
| 2014-04-29 | AC52067 | ND |
| 2014-04-29 | AC52065 | ND |
| 2014-04-29 | AC52063 | ND |
| 2014-04-29 | AC52037 | ND |
| 2014-04-29 | AC52059 | ND |
| 2014-04-29 | AC52039 | ND |
| 2014-04-29 | AC52071 | ND |
| 2014-08-11 | AC63095 | ND |
| 2015-08-12 | AD03968 | ND |
| 2016-02-17 | AD24323 | ND |
| 2016-05-17 | AD37069 | ND |
| 2016-07-20 | AD45007 | ND |
| 2016-11-09 | AD57412 | ND |
| 2017-05-09 | Q1719085002 | ND |
| 2018-02-28 | Q1808687007 | ND |
| 2019-05-07 | Q1920785002 | ND |