Assessing microplastics, per- and polyfluoroalkyl substances (PFAS), and other contaminants of global concern in wadable agricultural streams in Iowa

Authors: MEPPELINK, SHANNON - Us Geological Survey (USGS); KOLPIN, DANA - Us Geological Survey (USGS); LEFEVRE, GREGORY - University Of Iowa; CWIERTNY, DAVID - University Of Iowa; GIVENS, CARRIE - Us Geological Survey (USGS); GREEN, LEE - University Of Illinois; HUBBARD, LAURA - Us Geological Survey (USGS); Iwanowicz, Luke; LANE, RACHAEL - Us Geological Survey (USGS); MIANECKI, ALYSSA - University Of Iowa; O'SHEA, PADRAIC - Us Geological Survey (USGS); RAINES, CLAYTON - Us Geological Survey (USGS); SCOTT, JOHN - University Of Illinois; THOMPSON, DARRIN - University Of Iowa; WILSON, MICHAELAH - Us Geological Survey (USGS); GRAY, JAMES - Us Geological Survey (USGS)

Submitted to: Environmental Science: Processes & Impacts
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2025
Publication Date: 3/28/2025
Citation: Meppelink, S.M., Kolpin, D.W., Lefevre, G.H., Cwiertny, D.M., Givens, C.E., Green, L.A., Hubbard, L.E., Iwanowicz, L.R., Lane, R.F., Mianecki, A.L., O'Shea, P.S., Raines, C.D., Scott, J.W., Thompson, D.A., Wilson, M.C., Gray, J.L. 2025. Assessing microplastics, per- and polyfluoroalkyl substances (PFAS), and other contaminants of global concern in wadable agricultural streams in Iowa. Environmental Science: Processes & Impacts. 27:1401-1422. https://doi.org/10.1039/D4EM00753K.
DOI: https://doi.org/10.1039/D4EM00753K

Interpretive Summary: Microplastics, per- and polyfluoroalkyl substances (PFAS), antibiotic resistance genes (ARGs), pharmaceuticals and personal care products (PPCPs), and pesticides are pervasive in the environment. Here, agricultural watersheds in Iowa were surveyed to establish baseline concentrations and gradients of these contaminants based on land-use. Monitoring the contaminants of global concern is critical to evaluate effects of land-uses and inform sustainable, minimally impactful practices.

Technical Abstract: Microplastics, per- and polyfluoroalkyl substances (PFAS), antibiotic resistance genes (ARGs), pharmaceuticals and personal care products (PPCPs), and pesticides cause unintentional environmental contamination through many pathways in multiple matrices. This statewide, multi-matrix study of contaminants of global concern (CGCs) in agricultural streams across Iowa (USA) is the first to examine multiple CGCs in water, bed sediment, and fish to understand their occurrence in small streams located in regions of intense agriculture activity. Iowa plays a pivotal role in agriculture, with more than 85% of Iowa’s landscape devoted to agriculture making it an ideal location for determining the prevalence of CGCs to provide critical baseline exposure data. Fifteen sites were sampled across a range of dominant land uses; all sites had detections of microplastics in all matrices. PFAS concentrations varied but were detected in water and sediment; all fish had detections of PFOS. ARGs were detected in more than 50 percent of water and bed sediment samples and metformin was the most frequently detected PPCP. No sites had a cumulative exposure activity ratio >1.0 for chemical exposures but all sites were above the 0.001 precautionary threshold. Toxicity quotients calculated using Aquatic Life Benchmarks were all below the 0.1 moderate risk threshold for chemical exposures; all sites exceeded the moderate and high-risk thresholds proposed for microplastic particles for food dilution (both chronic and acute exposures). All sites exceeded the microplastic moderate threshold proposed for chronic tissue translocation, and 2 sites exceeded the threshold for acute tissue translocation.