Assessment of 1,4 Dioxane in Private Drinking Water Wells
Emerging contaminant 1,4 Dioxane was detected in drinking water from several private wells located downgradient of the Eastham Landfill. Since the Town was not at the time served by a municipal water system, private well water was the only source of drinking water for these residents.
The chemical and physical properties of 1,4 Dioxane make it difficult to remove from water, which renders most conventional water treatment technologies ineffective. Because it does not adsorb onto soil and does not biodegrade or volatilize, it is very persistent and mobile in groundwater.
ES&M was retained by the Town to determine the extent of 1,4 Dioxane so that the affected residences could be provided bottled water, and to evaluate water treatment technologies that could be used to remove 1,4 Dioxane from private well water.
ES&M implemented a focused sampling program to identify drinking water wells that may be impacted by 1,4 Dioxane related to the landfill. We also are conducting background studies to better understand the distribution of this compound in groundwater outside of the study area. We are working with a qualified laboratory to utilize the most up-to-date analytical methods to detect 1,4 Dioxane below the newly promulgated drinking water standard. We have collected samples from well over 200 private wells. The analytical results are managed in an extensive database that allows thorough evaluation of the data and facilitates prompt reporting of the results to the homeowners. The results of this study are being used to define the area of 1,4 Dioxane impact from the landfill and to ensure that residents’ drinking water is safe.
One of the most significant challenges has been distinguishing 1,4 Dioxane associated with the landfill from other sources in the aquifer. Our research has shown that many consumer products contain this compound, and, since every home has a septic system in addition to a private well, there are clearly many mechanisms that introduce 1,4 Dioxane into the environment. We conducted a septic study in one neighborhood to demonstrate that multiple sources of this compound are present.
ES&M designed two pilot tests for the removal of 1,4 Dioxane from drinking water. One test is ongoing, and is evaluating activated carbon adsorption, while the other test involved the use of an ozone/UV light treatment system. Estimated costs for point-of-use systems were developed such that Town officials could evaluate these costs vs. development of a public water supply system.
ES&M represented the Town at several meeting with MassDEP and presented at several public meetings. Our efforts helped the Town meet its regulatory requirements with available funding and our education of local citizens through community outreach helped the Town garner support for a municipal water supply system.