Mercury Levels in the River Otters (Lutra lutra) of Iran: Feasibility of Back Calculation for Trace Elements Using Old Stuffed Specimens

Otters at the top of the food chain and feeding largely on fish are likely to be especially vulnerable to the effects of bioaccumulating pollutants. This research reports the first data on mercury levels found in hairs of river otters (Lutra lutra) from Iran. Between June and December 2007, we collected museum and recent collections of river otter hair. These samples were collected from several provinces of three major regions of Iran. The mean of mercury concentration for all samples (recent and museum) was 5.819±1.557 mg/kg with 95% confidence interval for the mean. The concentrations of Total Hg (THg) in hair ranged from 0.293 to 12.382 mg/kg. No significant variation among the sample regions existed. A comparison of THg concentrations between two decades (1986-1996 and 1996-2006) showed that these differences were significant (psignificant difference was found between museum and recent specimens. This study has shown that the river otter has been exposed to THg with increasing trend in two past decades.