Testing by the Chesapeake Bay Foundation has found periodic spikes in levels of e. coli bacteria in some local waterways, a trend likely indicating runoff impact from nearby farms and waste treatment plants.

While this does not necessarily indicate a danger to the public, CBF Pennsylvania Executive Director Harry Campbell said in a news release that “We hope the takeaway from this study is that we all must do more to reduce polluted runoff and to use caution when considering going into the water within 48 hours of a heavy rain.”

Water samples were taken 14 times between June 1 and Aug. 9 at each of 10 locations, six in Cumberland and four in Dauphin counties. The Cumberland locations involved three points along the Conodoguinet Creek and three along the Yellow Breeches Creek. Levels of E. coli were measured in colony-forming units (cfu) per 100 milliliters of water.

The largest spikes were seen in the Yellow Breeches at the South Middleton Park test site. Levels of 127 cfu/100 ml on June 24 shot up to 2,420 cfu/100 ml on June 29, after a heavy rain.

The Environmental Protection Agency considers 235 cfu/100 ml to be the acceptable limit for swimming. In total, nine of the 15 samples taken at the Yellow Breeches following rainfall had e. coli levels above that limit.

The hazard is typically not E. coli itself – most strains of the bacteria are harmless, and naturally occur in the intestines of all warm-blooded animals. However, heightened levels of E. coli can correlate with other pathogens entering the water stream which are harder to detect, and thus E. coli levels are used as a proxy for general exposure to runoff from human or animal waste.

“E. coli and fecal coliforms are easy-to-measure indicators of bacteria that are used to test for contamination of human or animal waste,” Renee Reber, CBF staff scientist, said in the release. “They are a normal part of intestinal biology. The presence of this bacteria in the water does not guarantee risk to human health, but suggests pathogens may be present which can cause gastrointestinal illness, headache, and other symptoms.”

Without further, much more expensive testing, there is no way to determine if the E. coli in Cumberland waterways is harmful or if it comes from human or animal sources, according to CBF spokesman B.J. Small.

But runoff from farms and sewage treatment plants is a known problem in Pennsylvania, and the post-rain spikes found by CFB likely indicate Cumberland’s waterways are impacted to some extent by this effect.

“That’s why sewer plants are given tighter and tighter limits, and why we’re out doing inspections on farms,” said Carl Goshorn, director of the Cumberland County Conservation District, the local partner for the state’s Department of Environmental Preservation.

Early this year, Pennsylvania launched a “Chesapeake Reboot” plan in response to the EPA withholding $2.9 million in funding from the state for failure to meet pollutant reduction goals.

The new program is intended to ramp up Pennsylvania’s control efforts. The focus is on nitrogen, phosphorus, and sediment levels, which are typically washed into waterways from fertilizer spreading. These alter the chemistry of the Chesapeake Bay and have been blamed for algae blooms and the deterioration of aquatic life.

“Presumably, if you clean up those contaminants, you’ll clean up other pollutants as well,” Goshorn said. “We don’t regularly test for E. Coli, but we do have an individual testing program where owners can come to us with samples.”

As part of the reform effort, the DEP will begin having local conservation agencies do enforceable inspections, meaning the local office could write citations. Goshorn’s office previously only did advisory visits.

“Our board actually just approved our strategy to do inspections for the ‘Reboot’ requirements,” Goshorn said. “The DEP has to approve it and once that’s done, we’ll be starting the new inspections sometime in the fall.”