lead in rivers from snagging

[fishfish]

Back in the day when it was legal in  Genesee River by driving park bridge snagging salmon. There must be dumpster loads of old lead in them rocks. Is there a study before and after the falls ? Water lead levels ? 

[LongLine]

Not that I know of.  Historically treatment plants have discharged into the river and still do however they treat for it and have very strict limits on heavy metals'