“More than a year after first taking action, the military is still working to stop unregulated chemicals from flowing into waterways around the former Naval Air Station-Joint Reserve Base Willow Grove and the active Horsham Air Guard Station.

At a quarterly Restoration Advisory Board meeting last week at Horsham Library, officials from the Navy and Air National Guard, which are handling cleanups of their respective portions of the base, reviewed what has been done so far and what is being planned.

Firefighting foams containing perfluorinated compounds, or PFAS, were used previously on the base, and the unregulated chemicals have been found in groundwater there and in drinking water in nearby communities including Warminster, Horsham and Warrington…

Park Creek connects to Little Neshaminy Creek just downstream of the Air Guard station and the chemicals have been found in the waterways at levels well above the U.S. Environmental Protection Agency’s lifetime health advisory limit of 70 parts per trillion.

In September, the Air Guard installed a carbon filtration system on a stormwater basin that discharges to the creek and at one point contained about 11,700 ppt of PFAS.

The filter appeared to work and samples taken in October showed treated stormwater leaving the basin contained about 2 ppt, but heavy rain overwhelmed the filter and it was clogged by organic material and levels in March increased to 3,380 ppt, Matthew Machusick, a representative from Air Guard contractor Leidos, said last week.

Additionally, samples taken in March of water flowing into Park Creek from the base contained about 3,030 ppt, which was lower than samples taken in October. However, levels in Park Creek increased over that time frame, from 73 ppt to 151 ppt.

Similarly, levels in the Little Neshaminy Creek were about half what they were in October; levels in the main branch of the Neshaminy Creek nearly doubled to 117 ppt.

Machusick said the Air Guard is planning to replace the filter this week and add a pre-treatment system to prevent it from clogging, after which officials hope levels will drop again.

The Navy’s presentation also outlined work done as part of the first phase of its remedial investigation to expand stormwater basins and to close outfalls that carried groundwater from its portion of the base to Park Creek.”

Read the full article by Jenny Wagner