Microplastic atmospheric pollution in an urban Southern Brazil region: What can spider webs tell us?

Abstract

The World Health Organization categorizes air pollution as the presence of oneor more contaminants in the atmosphere such as smoke, dust, and particulatematter like microplastics, which are considered a priority pollutant. However, onlya few studies have been developed on atmospheric pollution, and knowledgeabout MPs in the atmosphere is still limited. Spider webs have been tested andused as a passive sampling approach to study anthropogenic pollution. Despitethis, studies on microplastic contamination using spiderwebs as samplers arescarce. Thus, this study uses spider webs as passive indicators to investigate airquality regarding microplastic contamination in an urbanized area. Therefore, 30sampling points were selected, and webs of Nephilingis cruentata were collected.The spider webs were dipped in KOH 10%. After digestion, the solution waswashed and sieved through a 90 µm geological sieve. The remaining materialwas transferred to a Petri dish with filter paper, quantified, and identified by typeand color. The chemical composition of the polymers was determined usingRaman spectroscopy. 3138 microplastics were identified (2973 filaments and 165fragments). The most frequent colors were blue and black. Raman spectroscopyrevealed five types of polymers: Isotactic Polypropylene, PolyethyleneTerephthalate, Polyurethane, Polyamide, and Direct Polyethylene.