1,4-dioxane found in Delaware, Lehigh Rivers
| February 4, 2021
A manmade chemical called 1,4-dioxane “a likely human carcinogen,” has been found in the Delaware River in the more industrialized section of the river and in the Lehigh River and south — that part of the river designated by the Delaware River Basin Commission as Special Protection Waters.
Here’s some mapping of the sites: www.drbc.maps.arcgis.com
Until this discovery, the chemical has not recently been found in the Delaware River. According to the Delaware River Basin Commission,”older data in the National Water Quality Data Portal suggests elevated concentrations in some southeast Pennsylvania tributaries.”
It was found initially by New Jersey American Water in February of 2020 in its testing of its intake at river mile 110 at its plant in Delran, N.J. The Delaware River Regional Water Treatment Plant serves approximately 45 communities in Burlington, Camden and Gloucester counties.
1,4-dioxane is commonly used by industries and federal facilities.
Here’s the DRBC’s slide presented at the Jan. 28, 2021, Toxics Advisory Committee meeting that explains more about it:
The Treatment Subcommittee of the New Jersey Drinking Water Quality Institute issued a report on the treatment of 1,4-dioxane in October 2020 that suggests: “The combination of ozone (O3) with hydrogen peroxide (H2O2) has been shown to be an effective technique for the treatment of 1,4-dioxane.”
Link to Report: www.state.nj.us
Not all drinking water utilities have both treatments. Denise Venuti Free, director of communications for N.J.American Water, explained N.J. American Water’s process in an email:
The Delaware River Regional Water Treatment Plant utilizes three of the most high-tech water treatment processes: ozonation, high-rate clarification and granular activated carbon filtration. Since ozone is one component of an Advanced Oxidation Process (AOP) used to treat 1,4-dioxane, this has been effective in removing most of the compound. Preliminary work to install a second component of AOP is underway, with full treatment capable of coming online in 2021, in advance of when the anticipated NJ DEP regulation might become effective.
In addition to the required monitoring for regulated compounds, New Jersey American Water monitors both raw water sources and our finished water for several emerging compounds, beyond what is required by the NJ DEP. New Jersey American Water has been monitoring the presence of 1,4-dioxane weekly since February 2020.
The Philadelphia Water Department’s intake on the Delaware River is quite close to the N.J. American Water intake in N.J. Here’s part of a statement from the Philadelphia Water Department (It’s printed in its entirety at the end of this story):
After hearing of detection by our utility partner in NJ, PWD proceeded to test source water proactively and voluntarily in an abundance of caution. PWD began monitoring 1,4-dioxane levels twice a month in our source waters in November 2020.
These results will be vetted, analyzed, and interpreted by PWD scientists and water quality experts to ensure adherence to a scientifically sound process. The scientific process includes repeatable observations that are made at different times of the year and under different weather and river conditions. PWD is collaborating with neighboring utilities (NJ American) and regulatory agencies (DRBC) to share information and assess risk in our watershed. We recently submitted a request to participate in the regional task force our partners are forming to better understand and address this issue.
Pennsylvania Department of Environmental Protection has so far not responded to repeated requests for a statement.
N.J. American Water notified the Delaware River Basin Commission in February 2020. The DRBC found it in its center-channel boat-run testing in March 2020, according to the report by John Yagecic, manager, Water Quality Assessment for the DRBC given at the Toxics Advisory Committee.
The DRBC coordinated results with N.J. American Water and N.J. Department of Environmental Protection, alerted Pennsylvania Department of Environmental Protection and the Philadelphia Water Department — its intake is also at river mile 110.
After March, the boat runs were paused due to Covid and partially resumed in August.
The DRBC and N.J. American Water have been cooperatively monitoring for the chemical in November and December of 2020, focusing on the non-tidal river.
According to its presentation at the Toxics Advisory Committee meeting, there appear to be two separate areas of what it terms “elevated concern.” Here’s the slide:
Those river miles in the estuary roughly map out to be from the Ben Franklin Bridge south to the Commodore Barry Bridge.
Perhaps more surprising, the other area is the Lehigh River and downstream drainage from there.
Here’s the summary presented by the DRBC:
NJDEP convened a 1,4-dioxane External Working Group, with NJAWC, DRBC and PADEP and will hold monthly meetings of the work group.
For more information check out this site: www.nj.gov
Another site of interest: www.epa.gov
And here’s the Philadelphia’s Water Department complete statement on 1,4-dioxane:
- Philadelphia’s tap water is top quality, safe to drink, and consistently meets or exceeds state and federal standards, including those in the Safe Drinking Water Act.
- The Philadelphia Water Department (PWD) closely monitors national public health discussions regarding emerging contaminants. Experts with the department’s Watershed Protection Program and Bureau of Laboratory Services gather relevant data and information to better understand the occurrence and potential risks posed by such contaminants as part of our commitment to protecting public health.
- The compound 1,4-dioxane is an emerging contaminant that has been found throughout the United States. We have only been able to detect this compound in minute amounts, measured in parts per billion. There are no federal or state drinking water regulations for 1,4-dioxane applicable to Philadelphia.
- The Philadelphia Water Department began testing of Philadelphia drinking water for 1,4-dioxane as part of a national emerging contaminant study implemented by the EPA in 2013-2015 (UCMR 3). Results did not indicate any public health concern for Philadelphia’s drinking water. Results from this monitoring effort are publicly available on the EPA’s website: www.epa.gov monitoring-rule#3.
- With all emerging contaminants, the science is still evolving. We are committed to the scientific method and making decisions based on sound scientific data. We have been closely following the research and regulatory discussions in our neighboring states.
- After hearing of detection by our utility partner in NJ, PWD proceeded to test source water proactively and voluntarily in an abundance of caution. PWD began monitoring 1,4-dioxane levels twice a month in our source waters in November 2020.
- These results will be vetted, analyzed, and interpreted by PWD scientists and water quality experts to ensure adherence to a scientifically sound process. The scientific process includes repeatable observations that are made at different times of the year and under different weather and river conditions.
- PWD is collaborating with neighboring utilities (NJ American) and regulatory agencies (DRBC) to share information and assess risk in our watershed. We recently submitted a request to participate in the regional task force our partners are forming to better understand and address this issue.
- We continue to track the latest science on 1,4-dioxane and any potential impact on drinking water quality. We expect our monitoring strategy to evolve as we learn more from our research and collaborations with other water utilities and regulatory entities.