Table 3 Annual plastic deposition rates to 11 U.S. protected areas.

Estimated annual deposition rates of microfibers and plastic particles to national parks and wilderness areas of the United States. Data are based on observed deposition rates to each site from late 2017 to early 2019.

National park or wildernessStateSize (km2)Mean plastic deposition rate
(plastics m−2 day−1)
Metric tons of plastic per year
(visual counts)
Metric tons of plastic per year
(FTIR proportions)
Grand CanyonAZ4926112 ± 610.7–11.911.0–21.3
Wind River RangeWY725268 ± 69.3–11.110.9–22.3
Craters of the MoonID2893139 ± 107.7–8.811.5–19.3
Rocky MountainCO1047435 ± 89.4–9.84.2–9.0
Joshua TreeCA320054 ± 23.4–3.73.7–9.8
Uinta High WildernessUT1849120 ± 64.3–4.81.6–2.8
CanyonlandsUT136648 ± 71.2–1.53.0–6.1
Indian PeaksCO311148 ± 50.9–1.00.4–1.3
East RiverCO300140 ± 90.8–0.90.4–0.9
Great BasinNV312107 ± 50.65–0.720.4–1.3
Bryce CanyonUT14580 ± 60.22–0.260.4–0.8
All western protected areasUSA496,350132 ± 61012–24191185–3773