Samples from two rain events at 10 temporary sites near the plant showed concentrations ranging from non-detect to 5.2 parts per trillion to 630 ppt on Jan. 28–29. On Feb. 4 and 5, the sampling revealed levels of 9.98 ppt to 286 ppt.
For context, the state’s provisional health goal for drinking water is 140 ppt. DEQ pointed out that rain water isn’t usually consumed. However, later in the year, some households that collect rain in barrels could use it to irrigate gardens.
These results confirm that smokestack emissions combine with rain to chemically transform into GenX. Then the contaminated rain falls to the ground, polluting the soil and groundwater with the compound. Dozens of groundwater and private drinking water wells have tested positive for GenX, many higher than the state’s provisional health goal.
The Division of Air Quality collected the first two rainwater samples at 10 temporary testing sites located 0.9 to 2.9 miles from the midpoint of the two production facilities at Chemours, according to a DEQ press release. Sites were not chosen to correlate with separate private well testing; rather, they were positioned at eight perimeter spots on public land and at one private residence with the owner’s permission, with one additional site located nearly three miles northwest.
Using detailed forecasts developed by division meteorologists, DEQ placed the sampling containers at the sites about an hour before rain started and collected the samples within hours of the rain ending. A private lab in Wilmington, SGS North America Inc., conducted the analysis, as did the EPA’s lab in Athens, Ga. DEQ said it is analyzing meteorological data to factor in potential impacts of wind direction and velocity, as well as precipitation rates.
At the state’s direction, Chemours is also conducting its own rain analysis; those results will be released to the public when they are finalized.
DEQ has also required Chemours to install a new carbon adsorption technology for part of the facility’s emissions points. Engineering estimates suggest that this will significantly cut the overall rate of GenX emissions from indoor air at the facility, DEQ said.
In addition, Chemours is conducting emission testing from its process areas as required by the state, with monitoring by Division of Air Quality staff. A preliminary test was conducted on Jan. 9 to determine if the testing method developed was appropriate. A second sampling program was conducted on Jan. 22.
Samples are being examined for GenX and other perflourinated compounds by a Chemours contractor and the EPA’s Athens lab. Results are expected in coming weeks. Ongoing smokestack testing will be conducted, with an estimated five-week turnaround on results.