Grapes containing lead may produce wine containing lead. Recent health concerns about lead in wine have led to studies of lead in grapes. There are two principal sources of lead. One is from lead-rich automobile exhaust particles settling on both grapes and soil. This is a problem for roadside vineyards in particular, but one which is declining as the use of unleaded fuels increases. The other source is from prior use of the now-banned chemical insecticide lead arsenate, which has contaminated many vineyard soils, especially where soil acidity is high.