The tissue ratio of parent OCPs to their metabolites indicates the time of exposure. HCH derivatives were determined to be present in livers at generally higher concentrations at Is¸ ıklı station, which was not supported by water concentrations except ˛-HCH. Based on liver results, aldrin concentration in Is¸ ıklı was similar to Sarayköy station; while it was lower than 1/10 in Söke compared to other two stations. Dieldrin is the degradation product of aldrin. It was not detected in livers at Is¸ ıklı station, while the aldrin/dieldrin ratio was found to be 1.7 at Sarayköy station and 0.3 at Söke station. Although these results suggested that the most recent aldrin entry may be at Is¸ ıklı, it was detected only in water samples from the Sarayköy station