PRESENCE OF NITRATES AND NITRITES IN WATER FOR HUMAN CONSUMPTION AND THEIR IMPACT ON PUBLIC HEALTH IN SUGARCANE-PRODUCING AREAS

Abstract

Water pollution has emerged as a consequence of human settlements, as well as from specific rural, agricultural, forestry and industrial activities within a region. It has been found that increasing use of nitrogen fertilizers also increases water pollution. Nitrates and nitrites that are dissolved in groundwater used for human consumption cause adverse health effects, such as production of nitrosamines (cause of cancer) and decrease of oxygen carrying capacity of the blood, known as blue baby syndrome. The aim of this study was to determine the relationship between the concentration of dissolved nitrates and nitrites in drinking water, and the incidence of esophagus and stomach cancer in the population living close to agricultural areas. The maximum concentration of nitrates (NO3-) in water for human consumption was 7.5 mg L-1. A total of 45 cases of esophagus and stomach cancer were identified, distributed in six agricultural municipalities studied. A weak correlation (r = 0.46, p < 0.05) was found between the factor of rational use of nitrogen in sugarcane cultivation and the number of cancer cases recorded in the area of study.