MICROPLASTICS FOUND IN WASTEWATER EFFLUENT FLOWING INTO THE SUSQUEHANNA RIVER

Microplastic filaments have been identified in effluent water samples flowing from the Eastern Snyder County Water Authority, located on the Isle of Que in Selinsgrove, PA, into the Susquehanna River. In a study last year, microplastics were recognized in the digested remains of crayfish collected from the bellies of smallmouth bass caught from tributaries of the Susquehanna near Jersey Shore, Sunbury, and Harrisburg. As part of a class project, Susquehanna University students collected water samples from a local wastewater treatment plant to determine if the facility was a source of microplastics in the Susquehanna River. Both plastic and glass liter bottles were used to sample effluent water. Samples of wastewater were collected and filtered using a Buchner funnel filtration system and #1 paper. The effluent from washing laundry (containing fleece) was also filtered. The filters were examined using binocular microscopes, and plastic particles were described, identified, and measured.

Preliminary data indicate that water samples from the wastewater treatment plant effluent were dominated by filamentous microplastics less than 40 µm in length. The filaments are colorful, and ranged from 2 to 40 µm in length, with an average length of approximately 4 µm and were ~0.2 µm wide. The fibers examined form the wastewater treatment plant filters resembled fibers collected from fleece filtered from washing machine effluent.

This exercise demonstrates that wastewater treatment plants may be a source of microplastics in the Susquehanna River. Though only 6% of the microplastics found in the crayfish study were described as fibers/filaments, it is thought that the fibers derived from laundry, that evade filtration in wastewater treatment plants, may be an underestimated and harmful environmental threat. Microplastics are known for attracting toxins in the environment, and when ingested by organisms, can introduce greater amounts of toxins and pollutants to higher levels in the food web. There are many wastewater treatment plants and other, different organisms in and along the Susquehanna River that may ingest microplastics. More work will be required to determine the true threat to this important natural resource.