“Greensboro officials seeking the source of a potentially harmful, drinking water contaminant are focused on a relatively small area that includes Piedmont Triad International Airport and its immediate surroundings.

Although months of additional study remain before they draw any final conclusions, water managers Steve Drew and Mike Borchers say that a major source of the pollutant PFOS appears to be training drills and actual emergencies at or near PTI during which firefighters deployed a highly effective, synthetic foam used to squelch fuel-based blazes…

In addition to training drills, instances where the foam might have accumulated in that area include crashes involving tanker trucks and long forgotten industrial fires or spills.

Meanwhile, the airport itself still could be contributing fresh sources of contamination: PTI conducts fire-training drills using firefighting foam once a year on its runway in the Greensboro watershed without cleaning up afterward, creating a possibility that additional PFOS is making its way into a nearby stream or ground water…

The area around PTI plays a pivotal role in the local saga because — from a strictly environmental standpoint — it’s about the worst place an airport could be sited, let alone an airport bordered by one of the nation’s larger tank farms and a variety of other industry.

PTI and its industrial surroundings sit at the crest of the region’s watershed, a part of Guilford County where key feeder streams rise and begin their separate journeys to reservoirs miles apart that supply both Greensboro and High Point with drinking water…

In actuality, water from the Mitchell plant has fluctuated between PFOS levels considered insignificant and those that are more concerning, with higher readings likely to occur after a rainy spell when PFOS-tainted groundwater or runoff presumably flows into Horse Pen Creek and other tributaries of the Lake Brandt municipal reservoir.

PFOS levels at the city’s other water treatment plant on Lake Townsend have not been so problematic. And Drew and Borchers said that they’ve seen nothing close to the advisory limit in continued testing at the Mitchell plant since its 2014 spike.

The city’s most recent round of tests in November found that water from the plant contained PFOS at 43 ppt and its sister compound at 7.2 ppt.”

Read the full article by Taft Wireback.