title: Low-Volatility Model Demonstrates Humidity Affects Environmental Toxin Deposition on Plastics at a Molecular Level.
abstract: Despite the ever-increasing prevalence of plastic debris and endocrine disrupting toxins in aquatic ecosystems, few studies describe their interactions in freshwater environments. We present a model system to investigate the deposition/desorption behaviors of low-volatility lake ecosystem toxins on microplastics in situ and in real time. Molecular interactions of gas-phase nonylphenols (NPs) with the surfaces of two common plastics, poly(styrene) and poly(ethylene terephthalate), were studied using quartz crystal microbalance and sum frequency generation vibrational spectroscopy. NP point sources were generated under two model environments: plastic on land and plastic on a freshwater surface. We found the headspace above calm water provides an excellent environment for NP deposition and demonstrate significant NP deposition on plastic within minutes at relevant concentrations. Further, NP deposits and orders differently on both plastics under humid versus dry environments. We attributed the unique deposition behaviors to surface energy changes from increased water content during the humid deposition. Lastly, nanograms of NP remained on microplastic surfaces hours after initial NP introduction and agitating conditions, illustrating feasibility for plastic-bound NPs to interact with biota and surrounding matter. Our model studies reveal important interactions between low-volatility environmental toxins and microplastics and hold potential to correlate the environmental fate of endocrine disrupting toxins in the Great Lakes with molecular behaviors.
authors.affiliation: Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States.
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Hankett
authors.affiliation: Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States.
authors.forename: William R
authors.initials: WR
authors.lastname: Collin
authors.affiliation: Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States.
authors.forename: Pei
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Michigan , 830 North University Ave, Ann Arbor, Michigan 48109 United States.
authors.forename: Melissa
authors.initials: M
authors.lastname: Duhaime
mesh_terms: D058448:Biota; D017753:Ecosystem; D052244:Endocrine Disruptors / Q000737:chemistry; D015386:Hazardous Substances / Q000737:chemistry; D006813:Humidity; D060106:Lakes; D008956:Models, Chemical; D010636:Phenols / Q000737:chemistry*; D010969:Plastics; D011093:Polyethylene Terephthalates / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D014835:Volatilization; D014866:Waste Products / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D052244:Endocrine Disruptors; D015386:Hazardous Substances; D010636:Phenols; D010969:Plastics; D011093:Polyethylene Terephthalates; D011137:Polystyrenes; D014866:Waste Products; D014874:Water Pollutants, Chemical; C025256:nonylphenol