METHYL-HEXACHLOROCYCLOHEXANE IN MUSSELS (MYTILUS-EDULIS) FROM THE MERSEY ESTUARY

Mussels from the Mersey Estuary have been found to contain notable con centrations of methyl-hexachlorocyclohexane methyl-HCH) and other, as yet unidentified, (chlorinated homologues or isomers of this compound. These materials have not previously been reported in the waters, sedi ments or biota of European estuaries. Identification of methyl-HCH and its probable isomers bv gas chromatography is complicated by retentio n time similarities with beta-HCH and other isomers of hexachlorocyclo hexane. Electron impact and chemical ionization mass spectrometry were used in conjunction with H-1 NMR to enable unequivocal confirmation o f methyl-HCH (1alpha, 2alpha, 3beta, 4alpha, 5beta, 6beta hexachloro-1 -methyl cvclohexane) as the major analyte of the suite of at least 13 peaks in the HCH region of the mussel trace.