In this investigation, the toxic effect of fluoride on 3 edible bivalve molluscs such as Meretrix meretrix , Paphia laterusulca and Katelysia opima has been studied. The impact of fluoride ions in different seasons on these bivalve molluscs indicates drastic changes and sensitivity especially in summer. The biochemical aspects revealed low and high concentrations of prokin and lipids depending on the conantrations of fluoride ions exposure. The bio-assay tests for % hrs. showed that K. opima was more sensitive to fluoride than M. meretrix. The results showed that the changes in the biochemical reserves were more significant in M. meretrix than K. opima.

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