Much arsenic contamination comes from natural sources, but mining has concentrated and released it in lots of places so that streams below mining areas have suffered a lot of damage. There are also a few industrial dumps that are notorious.

Although it's a little less toxic than the heavy metals, zinc contamination from mining is something of a problem in some areas.

A growing concern is contamination of refuse dump areas with cadmium and antimony, since both have been used in much greater quantities in "modern" storage (and primary) batteries that get dumped where they shouldn't be.

The once very common old practice of melting down old battery plates to recover the lead for hobby uses should now be considered extremely dangerous due to the "other heavy metals," some of which are extremely volatile at "casting temperatures."

Cadmium was once widely used for plating things like refrigerator shelf grids, and they'd occasionally get used as a "grill grid" by the unwary, with really bad effect due to inhalation of the cadmium evaporated at cooking/grill temperatures. So far as I know, most such "grates" now are generally either CRES or chromium plated. I suspect that it's a "regulatory requirement," but haven't checked on it. Chrome is just as toxic as cadmium or lead, but it's a lot harder to ingest, largely due to its high melting point, low volatility, and freedom from corrosion products with "unusual properties." Rhodium is similar to chrome, but is too rare to be used in "bulk products" so it hasn't appeared much as a public concern.

Cadmium is still used for plating a lot of nuts and bolts, so tossing unknown articles in the fire pit still can be somewhat hazardous.

The naturally occuring fluoride in groundwater varies a lot from one place to another. In SW Arizona it's so high that it's unsafe to drink the water. The military bases (Army and Marine) at Yuma AZ probably still provide bottled water for the people assigned/working there to avoid fluorosis, although I haven't checked on them since 40 years ago. Many of the "citizens" in the area did drink the local water, and the effects were obvious. Some places that add fluoride probably have enough naturally appearing that the need for an addition is questionable. "Conspiracy theories" and other objections still prevent adding it in many places where it probably could be of real benefit.

While the allegation that fluoridation is something pushed on people to get rid of an otherwise worthless product, others see it as an instance where medical research found something abundant and ridiculously cheap that could be of benefit. Few on either side seem inclined to change their opinions, so it doesn't merit much discussion (by me, at least).

John