Do your remember when someone first cautioned you to not eat the yellow snow? Likely referring to how urine will discolor snow in a yellow hue, check out the following publication using snow as a bioindicator of toxic metal pollution near a metal shredder in Winnipeg Ontario.
Solademi, Folarin, and Shirley Thompson. 2020. “Spatial Analysis of Heavy Metal Emissions in Residential, Commercial and Industrial Areas Adjacent to a Scrap Metal Shredder in Winnipeg, Canada.” Journal of Geoscience and Environment Protection 08 (05): 359. https://doi.org/10.4236/gep.2020.85023.
Looks like our heat maps derived from varying lead concentrations in moss suggesting metal shredding and recycling operations are a source of overlooked toxic metal air pollution.