https://en.wikipedia.org/wiki/Cloud_seeding
https://en.wikipedia.org/wiki/Climate_engineering
https://en.wikipedia.org/wiki/Stratospheric_aerosol_injection_(climate_engineering)
http://www.ncbi.nlm.nih.gov/pubmed/15236778
"High levels of Silver (Ag), Barium (Ba) and Strontium (Sr) and low levels of copper (Cu) have been measured in the antlers, soils and pastures of the deer that are thriving in the chronic wasting disease (CWD) cluster zones in North America in relation to the areas where CWD and other transmissible spongiform encephalopathies (TSEs) have not been reported. The elevations of Ag, Ba and Sr were thought to originate from both natural geochemical and artificial pollutant sources–stemming from the common practise of aerial spraying with 'cloud seeding'