Anthropogenic Litter in Illinois Streams: Monitoring, Distribution, and Relationship to Biological Indicators of Stream Health

Anthropogenic litter (i.e., trash; AL) is increasing in aquatic ecosystems worldwide. AL shows a patchy, uneven distribution in lotic ecosystems due to heterogeneity in its sources, how it moves, and mechanisms of retention. In addition, the diversity of material types, size, and mobility makes developing techniques to measure AL assemblage in rivers a challenge. In rivers, watershed land-use and riparian features likely impact AL abundance and composition, but this impact is not fully understood. Measuring AL can be time consuming and labor intensive, so rapid assessments are needed for ecosystem managers to quantify the level of AL impairment in a stream. The objectives of the research in this thesis were to 1) quantify the relationship between AL abundance, mass, and composition in streams to different watershed land use and a range of riparian features and 2) determine the efficacy of two rapid AL measurement methods: a qualitative assessment and a visual tally. We measured AL in 30-m reaches of 9 streams across northeast Illinois which span a gradient of land use and biological quality using the 2 rapid methods and manual collection. Results showed AL abundance (as No./m2) and the proportion of AL produced from single-use items (i.e., plastic and glass) were positively related to urban watershed land use, population density, and impervious surface cover and negatively related to agricultural land use. Local features that increase access to the river (e.g., proximity to roads and urbanized riparian zones) were associated with higher AL. The visual tally was predictive of AL density across sites as revealed through manual collection but underestimated total AL, particularly for ‘cryptic’ categories (i.e., easily overlooked or layered materials). Accurately quantifying AL abundance, composition, and relationships with watershed and stream features is essential to identifying the sources, transport, and fate of AL as well as supporting successful management of AL in streams

Talking Trash: Translating California Trash Monitoring Methods to Illinois Streams

Anthropogenic litter (i.e., trash; AL) is increasing in aquatic ecosystems worldwide. Rivers are both retention sites and conduits for AL. California was the first state to adopt regulations to categorize streams as \u27impaired\u27 for AL. Because AL contains a diversity of materials, with variable sources, degradation rates, and mobility, developing methods to measure AL assemblage is a major challenge. Our objective was to compare 3 AL measurement methods 1) qualitative rapid assessment, 2) quantitative visual assessment, and 3) manual collection. Methods 1 and 2 are in development for use in California. Using all 3 methods, we measured AL in 9, 30-m reaches of the North Branch Chicago River and in streams across Illinois that span a gradient of land use and biotic health as measured by the EPA. Results will illustrate how well management indices perform, and will directly improve measurement methods for AL as a newly regulated pollutant, and policies for stream ecosystem management

Garbage Science: Anthropogenic Litter Assemblage, Assessment, and Connections to Biotic Health in Illinois Streams

Anthropogenic litter (i.e., trash; AL) is increasing in aquatic ecosystems worldwide. Rivers are both retention sites and conduits for AL. Because AL is diverse in material types, uses, sources, and mobility, developing management techniques to measure AL assemblage is a major challenge. We measured AL in 30-m reaches of streams across northeast Illinois. Streams were selected based on landscape-scale land uses (urban, agricultural, and forested). Reaches in urban watersheds have significantly higher densities of AL than agricultural watersheds (ANOVA, p=0.015). The study will inform policies and practices regarding stream ecosystem management