Impact of toluene on ionic regulation and oxygen consumption of freshwater crab Sesarma boulengeri (calman)‎

الملخص EN

The present study has been conducted to explain the effect of sub lethal concentrations of toluene on some physiological aspects of freshwater crab S.

boulengeri including oxygen consumption rate, water and ionic regulation, bioaccumulation and histopathological effects.

Three sub lethal concentrations (2.5, 5.5 and 10.5 ppm) of toluene were used to study their effects during long term exposure (14 days) under 28° C.

The results showed that there was a positive correlation between oxygen consumption rate and toluene concentration.

Oxygen consumption rate reached to 0.223 mg O2 / g / h in 10.5 ppm toluene.

Body water content showed an increase to 71.17 % in 10.5 ppm toluene.

Ionic regulation also affected by toluene.

A significant decrease (P<0.01) was recorded in the level of Na+ in the haemolymph, as it reached to 245.5 mmol/l in 10.5 ppm toluene.

While K+ concentration in the lymph showed a significant increase (P<0.01) to 12.41 mmol / l comparing with the control.

Bioaccumulation of toluene in the gills in 5.5 ppm toluene reached to 2.98 mg/g dry wt.

during the 3rd day of exposure.

While it decreased to 1.34 mg / g dry wt.

during the 11th day of exposure.

Histopathological changes include swelling, hyperplasia, and hypertrophy in gill filaments.

Recovery data after 4 days of transfer to clean water showed that the physiological parameters studied (oxygen consumption rate, water and ionic regulation) did not return to the normal levels.