ABSTRACT
The objective of this investigation was to study the effect of prolonged exposure to nitrate polluted drinking water on blood methemoglobin [Met-Hb] level and other hematological parameters, as well as nitric oxide [NO] level in serum and urine [measured as indicator for nitrate toxicity] in male rats of two different ages, young [3 weeks-old] and adult [12 weeks-old]. Rats were administered sodium nitrate in drinking water at concentrations [100 mg/L = 8.7 mg/Kg, 250 mg/L=21.7 mg/Kg or 550 mg/L 47.7 mg/Kg] daily for four months. The obtained data showed a dose dependent reduction in the values of erythrocytes, leucocytes and platelets count, as well as jib content, Het%, MCV, NCH, MCHC and serum total iron in all nitrate exposed rats, with the marked decreases being occurred among the young animals. On contrary, nitrate exposure revealed a dose dependent increase in blood Met-Fib level, as well as NO production in serum and urine of all tested rats, however the young rats were more affected than the adult ones at different nitrate concentrations. This indicated that prolonged exposure to water nitrate pollution is a risk factor for developing increased Met-Hb level and the other hematological disorders in all the rats groups, particularly the when exposure started at young age which may contribute to the excess production of NO in response to nitrate exposure