All of the mined gold in the world is a cube about 70 ft on a side. Big cubes are hard to intuitively reason about.
If you took all of that non-recycled car battery lead waste and distributed it evenly across the whole U.S. population, you would have 6 orders of magnitude more than the absorbed dose required to give everyone in the country clinical lead poisoning.
(Obviously most of that waste has no likelihood of being absorbed into someone's body, so this calculation isn't necessarily that meaningful.)
Olympic sized pool = 164ft x 82ft x 9ft 10 inches = 132, 300ft^3. Density of lead: 709 lbs per ft^3.
So a single Olympic-sized pool would weight almost 94,000,000 lbs if filled with lead.
(If you really want to blow your mind, that same pool would weight almost 200 million lbs if filled with Osmium, the most dense element. Of course, that's WAY WAY more than the amount of Osmium that exists...I can't find a world wide figure but US production is only about 250 lbs per year)