1,4-Dioxane
City of Norco
1,4-Dioxane is a solvent classified by the EPA as a likely human carcinogen. It contaminates groundwater in many states due to industrial wastewater discharges, plastic manufacturing runoff and landfill runoff. Read More.
Animal studies show that 1,4-dioxane can target the liver, kidneys and respiratory system, and that prenatal exposure can harm the developing fetus. The State of California has set a Public Heatlh Goal of no more than 1 part per billion of 1,4-dioxane in drinking water. The state of Massachusetts sets a legal limit of 0.3 ppb, and New Hampshire's limit is 3 parts per billion. There is no national drinking water standard for this contaminant.
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 | 0.0914 ppb | 7 | 5 | ND - 0.170 ppb |
| 2015 | 0.129 ppb | 7 | 5 | ND - 0.350 ppb |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.35 ppb
The EWG Health Guideline of 0.35 ppb for 1,4-dioxane was defined by the Environmental Protection Agency as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-08-12 | B4H1135-05 | 0.120 ppb |
| 2014-08-12 | B4H1135-03 | 0.130 ppb |
| 2014-08-12 | B4H1135-01 | 0.140 ppb |
| 2014-08-20 | B4H2037-03 | ND |
| 2014-08-20 | B4H2037-05 | 0.170 ppb |
| 2014-08-20 | B4H2037-01 | ND |
| 2014-11-10 | B4K0871-01 | 0.0800 ppb |
| 2015-02-03 | B5B0293-09 | 0.170 ppb |
| 2015-02-03 | B5B0304-01 | 0.110 ppb |
| 2015-02-03 | B5B0293-05 | 0.140 ppb |
| 2015-02-03 | B5B0293-01 | 0.350 ppb |
| 2015-02-03 | B5B0293-03 | 0.130 ppb |
| 2015-02-10 | B5B0924-01 | ND |
| 2015-05-05 | B5E0286-01 | ND |