Experimental and field studies of effects of dichlorvos exposure on acetylcholinesterase activity in the gills of the mussel, Mytilus edulis L.

Abstract

Dichlorvos (DDVP) is an organophosphate medicine, used to treat ectoparasitic sea lice infestations of farmed salmon. Effects of this chemical on a non-target organism were investigated. Experimental exposure of mussels ( Mytilus edulis L.) to dichlorvos (DDVP) resulted in changes in gill acetylcholinesterase (AChE) activity with a hormetic increase at lower concentrations, and 50% inhibition at 3.6 μg l −1 after 24 h exposure. Repeat exposures resulted in cumulative inhibition. Twenty-four hour exposure to DDVP impaired the ability to close shells (EC 50 of 1700 μg l −1) and caused mortalities at high concentrations (LC 50 of 8200 μg l −1). AChE levels in mussels collected from sea lochs were indicative of DDVP inhibition related to the quantities of DDVP used. The use of AChE as a sublethal indicator of DDVP usage in the field is discussed.