DNREC says a pilot clean-up program is showing continued gains against pollutants in a channel off the Christina River.
The channel in south Wilmington – A-Street Ditch – is contaminated with PCBs or industrial toxic chemicals.
DNREC hydrologist John Cargill says the latest results offer a “so far, so good” story.
"The results are still significant, and they're still positive. Although if you compare the results from sampling to sampling we've seen a slight reduction in the positive results, but that's as expected from a scientific standpoint just because things are coming into equilibrium a little more," said Cargill.
The new report on July 2021 samples shows an innovative technology being tested in the A-Street Ditch cleanup project is reducing PCB levels.
The technology uses an activated carbon product called SediMite with PCB destroying microorganisms -- and over time the microorganisms degrade and destroy the PCBs.
Cargill says this latest reports shows they are getting the desired results from this effort
"The data that we've just published was from two years after the initial application, and initially I'd say that the mass reduction of PCBs still going up,” said Cargill. “What that means is that the bugs are eating PCB molecules, and we've seen an approximate 50% reduction in PCB mass in the sediments."
There was a slight increase of dissolved PCBs in the sediment porewater – water trapped between grains of sediment in the bottom of a body of water – but it is still 32% less than baseline conditions measured in 2019.
The final sample will be taken in June.
