MERCURY BIOACCUMULATION IN TISSUES OF FRESH WATER FISH CARASSIUS AURATUS GIBELIO (SILVER CRUCIAN CARP) AFTER CHRONIC MERCURY INTOXICATION

Marioara Nicula, P. Negrea, I. Gergen, M. Harmanescu, I. Gogoasa, M. Lunca

Abstract
The objective of the present study was to determine the mercury bioaccumulation level in various organs of a cyprinid fish, namely the silver crucian carp (Carassius auratus gibelio), after a 21 days chronic mercuric chloride exposure. We used a mercury sublethal dose of 0.25 ppm from a ClHg₂ stock solution. Mercury concentration in the tissue samples (gill, skin, intestine, muscle, cord, brain, liver, kidney) was assayed with the aid of a Spectr AA atomic absorbtion spectrophotometer, using the cool steam technique, and the results were given as mg/kg wet weight. In order, mercury bioaccumulation was: gill>liver> intestine and kidney>muscle>skin>brain>cord. High levels of mercury bioaccumulation in any tissues of the intoxicated animals definitely relieve that, mercury contamination of the aquatic ecosystems affect the life of the fish species, altering their metabolic functions. Hence, a scientific detoxification method is essential to improve the health of economic species of fish in any stressed environmental conditions (accidental or induced discharges of heavy metal.

Key words: chronic mercury intoxication, bioaccumulation, fresh water fish