After an on-site inspection, the North Carolina Department of Environmental Quality has confirmed Chemours has stopped discharging GenX into the Cape Fear River.
As the flow of that particular contaminant appears to have stopped for the time being, the focus shifts to the other contaminants that may very well still be present in our river and drinking water.
We first told you last week about one of those chemicals, 1,4-dioxane. It’s a likely human carcinogen according to the EPA, and researchers have found dioxane in both the river and the finished drinking water of CFPUA. The EPA has set the “safe level” of dioxane at .35 parts per billion.
For the Brunswick Regional water system, 2015 data taken in compliance with EPA's unregulated contaminant monitoring rule numbers show average 1,4-dioxane levels of 2.1, six times higher than the safe level.
Sampling the Wilmington water supply in 2015, NC State University Researcher Detlef Knappe found average levels of dioxane to be 3.8 in the raw water supply, but that number was reduced to 1.2 in the finished water supply that had been treated for customers. The ozonation process used by CFPUA helped bring the level down. That is still about three times higher than the safe level.
Scientists at the state Department of Environmental Quality (DEQ) say after Knappe mentioned his dioxane findings to them, they began monitoring the contaminant in the river as well.
“We monitored for two years,” explained DEQ water quality analyst Tammy Hill. “During the first year, we did find dioxane in several locations in the Cape Fear River basin. And department representatives met with municipalities upstream where those concentrations were found and then during the second year of the study, concentrations at almost every location dropped substantially.”
Hill suspects manufacturers upriver agreeing not to discharge those chemicals into the sewer system is the reason for the substantial drop in dioxane levels, but she said dioxane levels in the Cape Fear River at the end of the monitoring period were still higher in some cases than the EPA safe level.
Oddly, DEQ sampling methods are not sensitive enough to pick up the very low levels of dioxane even though they are considered to be unsafe at anything over .35 parts per billion.
“We don’t know how much [dioxane] there was. All we know is that it was less than two," Hill explained of the 2016 sampling data. "The laboratory instrumentation was not sensitive enough to pick up any amount less than two, so it could have been any amount between nothing and two, but we don’t know.”
Because technology is available that will indicate the presence of dioxane at levels lower than two, and because that information is potentially significant for the health of the people drinking from the Cape Fear River, we asked the DEQ why they weren’t using more sensitive testing technology.
“At this time, there is no EPA-approved method for surface water sampling,” Hill answered. “They could get to lower levels if they test the drinking water itself, and that would be done by the drinking water suppliers.”
CFPUA Executive Director Jim Flechtner explained that according to the EPA’s Unregulated Contaminant Monitoring Rule, they must test the drinking water for unregulated and potentially toxic chemicals in the water every five years. The last test was done in 2013, and the next required testing is set for September 2018.
CFPUA board member Pat Kusek asked Flechtner at a board meeting on Monday if they could test the water more frequently than every five years, to which Flechtner replied that they could, but the chemicals would still be unregulated and the board would not have any authority to stop the release of chemicals even if they were detected.
Since the meeting on Monday, the CFPUA's thinking on testing has evolved, and they now plan to partner with academic researchers to test the drinking water more frequently.
“We’re (currently) testing for GenX so we can document its levels now that Chemours has stopped discharging," Flechtner said. "It will be helpful for our customers to know when the levels drop off and how quickly. We’re including C8 because it’s been part of the GenX discussion and we’d like to document those levels as well.
“As far as other compounds, we would like to partner with researchers at UNCW or NC State to study whether other unregulated contaminants could be a concern. CFPUA doesn’t have the expertise or resources to design such a study and determine conclusions. I hope to partner on these studies as EPA decides which compounds to regulate. I expect to get this underway soon as we all have questions. Since we want to be sure and gather the right information and get meaningful results, we need help from academic researchers.”
Copyright 2017 WECT. All rights reserved.