2,4,5-TP (Silvex)
Patterson Water System
2(2,4,5-trichlorophenoxy) propionic acid (2,4,5-TP or Silvex) is a cancer-causing herbicide banned in the U.S. in 1985 because of its toxicity. It is still detected as a groundwater contaminant in areas where it was sprayed or stored.
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 | ND | 4 | 0 | ND |
| 2019 | ND | 8 | 0 | ND |
| 2020 | ND | 4 | 0 | ND |
| 2021 | ND | 2 | 0 | ND |
| 2022 | ND | 2 | 0 | ND |
| 2023 | ND | 2 | 0 | ND |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 3 ppb
The EWG Health Guideline of 3 ppb for 2,4,5-TP 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): 50 ppb
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-25 | 35370415002 | ND |
| 2018-01-25 | 35370415002 | ND |
| 2018-07-09 | 35403035001 | ND |
| 2018-07-09 | 35403035001 | ND |
| 2019-01-15 | 35442674001 | ND |
| 2019-01-15 | 35442674001 | ND |
| 2019-07-09 | 35480730001 | ND |
| 2019-07-09 | 35480730001 | ND |
| 2019-07-24 | 35484856001 | ND |
| 2019-07-24 | 35484856001 | ND |
| 2019-10-22 | 35507344001 | ND |
| 2019-10-22 | 35507344001 | ND |
| 2020-01-07 | 35522572001 | ND |
| 2020-01-07 | 35522572002 | ND |
| 2020-04-14 | 35544199001 | ND |
| 2020-09-28 | 35581278001 | ND |
| 2021-03-25 | 35621782001 | ND |
| 2021-11-30 | 35681445001 | ND |
| 2022-01-06 | 35688920001 | ND |
| 2022-07-28 | 35735506001 | ND |
| 2023-09-27 | 35830712001 | ND |
| 2023-10-09 | 35833383001 | ND |