Anthropogenic litter, particularly plastic, is ubiquitous in urban and suburban streams. In an effort to limit the amount of plastic waste in the environment, several nations and US states have enacted bans on distribution of single-use plastics (such as shopping bags and drinking straws). Other states, like Pennsylvania, do not have statewide bans, but do allow for municipal-scale bans on single-use plastics.
We conducted an 18-month study of nine headwater streams in southeast Pennsylvania to characterize the types and abundance of anthropogenic litter in stream beds and riparian zones. We categorized each piece of litter recovered according to the material of which it is composed and its use, in addition to recording the mass and size. In addition, we used a replicated before-after-control-impact study to ask how municipal-scale plastic bans affect the abundance and types of anthropogenic litter. Each of our sites had spatially-homogenous policy regarding single-use plastics within their watersheds, including three streams in municipalities without plastic bans, three streams that had plastic bans for at least one year before we began sampling, and three streams in which plastic bans were enacted partway through our sampling period. While we have shared preliminary results at past meetings, this presentation is the first to report on the full dataset from this study. We will describe the “community” of litter among sites, and describe whether and how the abundance and types of litter are affected by watershed characteristics and policy.