Toxicity of cadmium to Parachanna obscura : As evidenced by alterations in hematology,histology, and behavior

Fish of species Parachanna obscura are exposed to four concentrations of cadmium (Cd) (0.02, 0.06, 0.18, or 0.54?mg?L^?1). Acute toxicity test results after 96?h showed marked hematological, histological, and behavioral changes. Quantitative blood analysis revealed that white blood cell (WBC), packed cell volume (PCV), and platelets counts were linearly correlated with increasing Cd concentrations; however, blood haemoglobin (Hb) showed an inverse relationship, with higher Hb levels at lower Cd concentrations. Histological changes of the liver showed hepatic separation, bloody appearance, and deposition of a brownish-yellow substance, which increased with rising concentrations of metal. Behavioral changes observed included reduced activity, avoidance response, and deposition of a slimy-whitish film on the body of the fish, which increased with concentration and exposure time.     

Evaluation of hematological changes in population exposed to fluoride

Absorption of fluorine compounds produces chronic toxicity and the hematological changes appear earlier in blood than other organs. A study was undertaken to determine the status of hematological changes in the individual residing in fluoride-contaminated area. Two hundred and fifty nine and 233 subjects from the contaminated area and an unaffected area, respectively, were selected for hematological investigations. Total erythrocytes (red blood corpuscles (RBC)), total leucocytes (white blood corpuscles (WBC)), and hemoglobin (Hb) concentrations were determined in these populations. Results revealed that Hb values were significantly lower among all age groups in the exposed population compared to control subjects. There was a quantitative rise in WBC counts in study subjects compared to controls. The RBC counts showed reduction among exposed population.