Waste in the ponds produced by leaching gold from ore is a source of potential environmental dangers.
Gold production creates water pollution 
The gold production is create pollution that is in the water.  Water pollution.
( z1 create :ARG0 ( z2 produce :ARG1 ( z3 gold ) ) :ARG1 ( z4 pollute :ARG0 z2 :ARG1 ( z5 water ) ) )