Under barium exposure, significant changes in respect of oxygen consumption, respiratory rate, red blood cell count and glycaemia were recorded in the specimens of crucian carp studied being viewed as a response to the stress caused by particulate matter.

The interval of the non-lethal concentration of the barium at the Carassius gibelio Bloch,1782 individuals is situated between 1 – 1500 mg/l, and the lethal concentration DL₁₀₀ = 2000 mg/l. For the determination of DL 100 we used semistatic testing at 24 hours.

The highest variations of the physiological indices percentage-wise were seen in: glucose, whose value was in the control sample 49.33 mg/dl, and in the experimental sample, exposed to 40 mg/ l BaSo₄ was 87 mg/dl, representing an increase of 76.36% after 336 hours and red blood cell count where values increased significantly by 183%, 152% respectively 120.41% in concentrations of 40, 35 and 30 mg/l of BaSO₄.