Polycyclic aromatic compounds (PAC) in leaf lettuce.

Twenty-three samples of leaf lettuce (Lactuca sativa var. crispa) cultivated in private gardens in southern Finland were analyzed for polycyclic aromatic hydrocarbons (PAH) and derivatives. The total PAH concentrations varied from 4.8 to 94 micrograms/kg fresh weight. Nitro derivatives of PAH were detected in only five samples. One lettuce sample was also analyzed for PAH oxy-derivatives. 9H-Fluoren-9-one (1.3 microgram/kg) and 6 H-benzo[cd]pyren-6-one (0.3 microgram/kg) were found. The profiles of PAH in lettuce were compared with those in ambient air. It was concluded that PAH in lettuce originate from deposition of PAH-containing particles present in ambient air.