Kajian efek sinergis parakuat diklorida, timbal(II) dan besi(II) terhadap pembentukan DNA adduct 8-OHdG secara in vitro dan in vivo pada tikus (rattus norvegicus) = Study of the synergistic effects of paraquat dichloride, lead(II) and iron(II) on the formation of DNA adduct 8-OHdG with in vitro and in vivo study in rats (rattus norvegicus)