its interesting. i know when we start a job (MTO)we sometimes have to do winter sand removal. This has been on the side of the road for 10 to 20 years built up at guardrails. We the contractor have to dispose this contaminated stuff on site. i'm sure this in time is getting into our waterways. if its from sitting on the side of the roads or after our its been relocated. i wish the MTO would reuse this stuff and maybe save us tax payers a few dollars