Heptachlor epoxide
Orangewood Water System
Heptachlor epoxide is a breakdown product of heptachlor, a highly toxic and carcinogenic pesticide banned in the U.S. since the 1980s.
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 | 0.0400 ppb | 3 | 3 | 0.0290 ppb - 0.0500 ppb |
| 2019 | 0.0383 ppb | 3 | 3 | 0.0360 ppb - 0.0430 ppb |
| 2020 | 0.0218 ppb | 12 | 5 | ND - 0.0780 ppb |
| 2021 | 0.0257 ppb | 3 | 3 | 0.0220 ppb - 0.0300 ppb |
| 2022 | 0.0250 ppb | 3 | 3 | 0.0210 ppb - 0.0290 ppb |
| 2023 | 0.0115 ppb | 12 | 5 | ND - 0.0340 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.006 ppb
The EWG Health Guideline of 0.006 ppb for heptachlor epoxide 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 cancer.
EPA Maximum Contaminant
Level (MCL): 0.2 ppb
The legal limit for heptachlor epoxide, established in 1991, was based on analytical detection limits at the time that the standard was set. This limit may not fully protect against the risk of cancer.
ppb = parts per billion
All test results
| Date | Result |
|---|---|
| 2018-12-04 | 0.0410 ppb |
| 2018-12-04 | 0.0500 ppb |
| 2018-12-04 | 0.0290 ppb |
| 2019-02-07 | 0.0360 ppb |
| 2019-02-07 | 0.0430 ppb |
| 2019-02-07 | 0.0360 ppb |
| 2020-06-03 | ND |
| 2020-06-03 | ND |
| 2020-06-03 | ND |
| 2020-06-04 | 0.0640 ppb |
| 2020-06-04 | 0.0780 ppb |
| 2020-06-04 | ND |
| 2020-09-08 | 0.0200 ppb |
| 2020-09-08 | 0.0560 ppb |
| 2020-09-08 | 0.0430 ppb |
| 2020-09-09 | ND |
| 2020-09-09 | ND |
| 2020-09-09 | ND |
| 2021-06-02 | 0.0220 ppb |
| 2021-06-02 | 0.0300 ppb |
| 2021-06-02 | 0.0250 ppb |
| 2022-04-11 | 0.0250 ppb |
| 2022-04-11 | 0.0210 ppb |
| 2022-04-11 | 0.0290 ppb |
| 2023-03-14 | ND |
| 2023-03-14 | 0.0280 ppb |
| 2023-03-21 | 0.0260 ppb |
| 2023-03-21 | 0.0340 ppb |
| 2023-03-22 | ND |
| 2023-03-22 | ND |
| 2023-03-22 | ND |
| 2023-08-15 | ND |
| 2023-08-15 | ND |
| 2023-08-15 | ND |
| 2023-08-15 | 0.0220 ppb |
| 2023-08-15 | 0.0280 ppb |