AN INVESTIGATION OF SOURCES OF ENVIRONMENTAL POLLUTION AND ITS IMPACT ON GROUNDWATER QUALITY IN MAZANDARAN PROVINCE, NORTH OF IRAN

摘要

The shared Caspian Sea, as the largest land-locked water body on earth, is of high global environmental significance. The Caspian Sea is bordered by Russia, Azerbaijan, Kazakhstan, Turkmenistan, and Iran (Mazandaran, Guilan and Golsetan proinces). Groundwater represents a significant share of the Caspian Sea inflows, and contributes to the water balance and the sea fluctuations through river runoff and as direct seepage into the Sea. Groundwater is a principal drinking water supply in the coastal zone in all the Caspian countries as well as for Mazandaran province (north of Iran). In recent years, the growth of industry, technology, population, and water use has increased the stress upon both land and water resources of Mazandaran province. In this research an investigation is made on the natural and human-induced impacts on coastal groundwater quality in Mazandaran province. After conducting comprehensive investigation on situation of water supplies in Mazandaran province and determination of main sources of groundwater pollution in this area, several water wells were tested to reveal the real quality of groundwater supplies of Mazandaran province in this research. Concentrations of heavy metals in some important water wells of Sari area as well as Babol area were measured in this research. In addition, some qualitative parameters of water wells were determined. The results on heavy metals and other parameters on Sari and Babol water wells when compared with the WHO standards show that the concentrations of Cu, Cr, Zn, and NO_3 are within standard limits while concentrations of Pb and Cd are often exceeding the WHO maximum permissible standard values. This investigation indicates that the main pollutants of groundwater resources in Mazandaran province are domestic, industrial and agricultural waste water discharges. Moreover, municipal and rural solid wastes pollute the water sources in this area. Furthermore, results of the present study show that groundwater quality in the upper watershed and middle lands of the Mazandaran province is reasonably good, whereas the quality of groundwater in the lower lands is progressively poor. As a consequence, even though the current quality of groundwater in Mazandaran province does not present immediate health related concerns, continuous monitoring will be required to prevent contamination of groundwater resources by serious sources that mentioned in the present study. Establishment of both monitoring programs and appropriate regulations to minimize uncontrolled discharges into groundwater resources is emphatically recommended for conservation of this valuable source of water supply in north of Iran.