Please see the DTSC September 1, 2015 Clarification letter correcting the units on the OEHHA public health goals for 1, 4-dioxane. We appreciate this correction.
Here is the original letter DTSC Response to ENU July 13 2015.
This correction is very important. Units matter a lot. In this case, since 1,4-dioxane has been measured at 290 ug/l underneath the Chatham Yard itself and has been measured in wells south of Via Rancho Parkway at 36 ug/l, it is clear that 1,4-dioxane is a concern related to the Chatham cleanup. DTSC has also confirmed that the 1,4-dioxane in our local groundwater plume comes from the Chatham site.
The Office of Environmental Health Hazard Assessment (OEHHA) sets the public health goal at 3 ug/l. According to OEHHA’s 2009 Public Health Goals for Chemicals in Drinking Water for TCE the general statement is made ….
standard adopted by DPH shall be set at a level that is as close as
feasible to the corresponding PHG, with emphasis on the protection of public health.
Each primary drinking standard adopted by DPH is required to be set at a level that
is as close as feasible to the corresponding PHG, with emphasis on the protection of
We think this should also apply to 1,4-dioxane.
According to DTSC, it is the domain of the Regional Water Quality Control Board to set any cleanup level for 1,4-dioxane in accordance with Resolution 92-49. ENU will be asking the Regional Water Board to establish that level soon.
Also to report that the regulatory agencies and the PRPs for Chatham met in August to discuss methods to preventing the discharge of Chatham pollution into Felicita Creek. We are anxiously awaiting the results of that meeting.
Have a great and safe Labor Day!