Peripheral blood smear neutrophil nuclear excrescence of 357 peasants inhabiting in 6 villages surrounding several oxidation ponds near Yaer Lake Ezhou City was investigated and the average values of 50.1%, 48. 8%, 44.9%, 45.3%, 44.3% and 41.6% for 6 villages respectively were reported, which were significantly higher than a value of 24.9% obtained from a group of people living in a non-polluted area. Of the residents in six villages, the excrescence ratio was negatively correlated to...