Determination of methyl-, ethyl-, phenyl and total mercury in Neckar River fish.

Methyl-, ethyl- and phenyl mercury, total mercury and fat content were determined in fish fillet of the five different fish species: eel, perch, roach, chub and barbel. The organo mercury compounds were extracted according to a modified Westöö method and determined by using HPLC-cold vapour atomic absorption spectrometrie. Total mercury was determined according to EPA/AOAC. Total mercury in fish tissue varied between 16 and 812 micrograms/kg, methyl mercury between 10 and 770 micrograms/kg. It was found that at least 83% of total mercury is present as methyl mercury. Only a barbel exceeded the German maximum acceptable residue limit (500 micrograms/kg) with 812 micrograms/kg total mercury.