Plastic ingestion by fishing cats suggests trophic transfer in urban wetlands

Recent studies have suggested that plastic contamination in some terrestrial and freshwater environments is estimated to be greater than that detected in marine environments. Urban wetlands are prone to plastic pollution but levels of contamination in their wildlife are poorly quantified. We collected 276 fishing cat (Prionailurus viverrinus) scat samples in Colombo, Sri Lanka for a dietary study of urban fishing cats. We used traditional dietary analysis methodology to investigate the contents of the scats by washing, isolating, and identifying prey remains; while sorting prey remains of individual scats, we unexpectedly detected macroscopic (>1 mm) plastic debris in six (2.17%) of the samples. Across all scat samples, we detected low occurrences of microplastics (0.72%), mesoplastics (1.09%) and macroplastics (1.45%). All three plastic types were found in scats containing rodent remains, while meso-, and macroplastics were found in scats with avian remains, and micro- and macroplastics in scats containing freshwater fish remains. Given that felids are obligate generalist carnivores that eat live or recently dead prey and do not consume garbage, our findings suggest that trophic transfer of plastics occurred whereby fishing cats consumed prey contaminated with plastic. Although macroscopic plastic detection was low, our findings suggest that accumulation of plastics is occurring in wetland food webs, and plastic pollution in freshwater terrestrial systems could pose a risk to predators that do not directly consume plastics but inhabit contaminated environments.

Ridding our rivers of plastic: A framework for plastic pollution capture device selection

Rivers are a major pathway for the transport of plastics into the ocean. Plastic pollution capture devices offer one way to reduce the accumulation of plastic in the environment. This paper provides a framework for selecting a device to reduce plastic pollution in freshwater, synthesizing information of forty prevailing plastic pollution capture devices. We distinguish three major components of plastic pollution technology (booms, receptacles, and watercraft vehicles) and collect details on each technology including its features, limitations, efficiency, reported costs, and maintenance requirements. A framework is developed to aid in device selection by water and waste managers, which highlights the need for a watershed assessment, an understanding of site conditions, the attainment of community buy-in, and a long-term maintenance plan. While plastic pollution capture devices can help reduce the flux of plastic waste from freshwater, management of plastic waste at the source is also needed to ultimately clean our oceans and waterways.