Naturally, it varies - but typical midwestern (where a majority of our crops are grown) vary between 1-30%. Now run the numbers of how much Aluminum it would take to make your aluminum soar 4x higher. 1 cubic yard weighs a bit north of 2100 lbs. 1% is 21lbs. 5% would be 105 lbs; so one is to believe that 84 lbs of aluminum was spread across every cubic yard of top soil in the Midwest. That's a lot of aluminum
And why would you think it's zero? The data is pretty easy to look up.
https://www.epa.gov/sites/default/files/2015-09/documents/eco-ssl_aluminum.pdf
Naturally, it varies - but typical midwestern (where a majority of our crops are grown) vary between 1-30%. Now run the numbers of how much Aluminum it would take to make your aluminum soar 4x higher. 1 cubic yard weighs a bit north of 2100 lbs. 1% is 21lbs. 5% would be 105 lbs; so one is to believe that 84 lbs of aluminum was spread across every cubic yard of top soil in the Midwest. That's a lot of aluminum