Patches of foam on Penns Creek sparks exploration into causes and encouragement to follow curiosity

Like white tufts of shaving cream floating atop bathwater toward a nearby drain, seemingly bright-white patches of foam have been a regular early morning sight on the lower Penns Creek lately.

In a May 2020 blog post, we talked about foams on waterways and how to tell when they are naturally occurring vs. when they could be a sign of pollution.

Usually, foams that have a dirty look and an earthy or fishy smell can typically be connected with natural organic matter such as fats, lipids and deteriorating leaf matter getting whipped up in rapids much like egg whites can be whipped into stiff peaks of frothy meringue.

​However, the patches of stiff peaks I noticed floating down the Penns Creek over the past month or two were, from a distance at least, bright white and very unnatural in appearance. It was also odd that I'd usually only see them during the morning hours. By afternoon to evening, they'd be completely gone.

So, early one recent morning, I waded out into the creek to a small set of rapids where a few of these foam tufts were congregating. As white as they seemed from a distance, up close, it was much easier to see more natural hues of browns and greens.

Grabbing some foam with a gloved hand, I noticed it wasn't as slimy, soapy or symmetric as the sudsy bubbles from washing dishes in Dawn in my kitchen sink.

The smell was equal parts earthy and aquatic -- much more natural than the industrialized detergent aromas I was anticipating.

I collected some of the foam with creek water into a sample bottle and noticed the foam bubbles popping and receding fairly quickly. I shook the bottle, expecting it to replenish the froth like a bottle of soapy water. Instead, the foam disappeared even more. The water left behind was brownish-yellowish hue and contained a few dead macroinvertebrates and other organic material.

Samples of the foam were taken to a local lab for processing, just to be sure there wasn't an underlying contaminant I might be missing. Results of that testing are still pending.​

Riverkeeper John Zaktansky holds up a collection of foam and creek water from Penns Creek in Snyder County before it is sent off for analysis.

Pockets of white foam have been aggregating in certain sections of Penns Creek and other waterways -- usually most visible during the early morning hours.

Increased leaves and other organic matter in our waterways can break down and be influenced by a variety of elements in forming natural creek foam.

However, after interacting with the substance, I feel much more confident it was a natural phenomenon where all the right conditions had merged -- the necessary organic matter from early autumn's leaves and other debris mixing together and churned up by rapids running over additional rock structures exposed due to a lower-than-normal water table. Lack of sunlight overnight, a differential in temperatures between the water and the quickly cooling fall air and likely numerous other factors all combined into a perfect foamy storm.

Interestingly, around the same time as my foam-focused investigation, I was contacted by a researcher out of the University of Florida in relation to a report we shared out concerning PFAS testing and discovery in the Susquehanna River. He is doing a study on PFAS -- chemicals used in a wide variety of products (firefighting foam, non-stick cookware, fast food wrappers, rain gear, certain cosmetics, etc.) that naturally repel water -- and how they may be more concentrated in ocean/river/creek foams.

I collected a sample of the Penns Creek foam and sent it to this researcher to be included in his study. I am anxious to see what he finds as it would make a lot of sense for these unnatural water-resistant chemicals to whip up into the foams we find on our waterways. 
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As we wait for results, I wanted to share this story as an example of how curiosity and follow-through can lead to some interesting discoveries. As you explore the creeks, lakes and interconnected river system in our greater watershed, I encourage you to follow your own curiosity as you come across things you may not understand or think odd or out of place.

Share your discoveries with me at [email protected] or 570-768-6300. Also, if you haven't yet explored the Water Reporter app and our interactive map of reports, I would encourage you to visit middlesusquehannariverkeeper.org/report-a-concern.html, download the app and share what you find.