Investigation of Pb, Zn and Ni in Watershed of Anzali Wetland (case study: Goharrood River)

Heavy metals are the most important pollutant factors of water resources specially rivers. Entrance of metals in natural aquatic ecosystems arises from discharging of domestic, agricultural and industrial sewage. With respect to the health risks possibility and also importance of aquatic ecosystems, in this study the amounts of Pb, Zn, Ni elements in Goharrood river of Rasht were measured. The samples were collected in nine stages from five stations. Experiments were done by atomic absorption instruments. Results showed that the average amounts of Pb, Zn and Ni all along the river were respectively 3830, 156 119,31 15 ppb. Maximum amounts were measured as follows: Pb 168 ppb in station 3, Zn 513 ppb in station 4 and Ni 60 ppm in station4. ANOVA doesnt show significant difference between the measured average amounts of Pb, but there is significant difference between the average amounts of Zn and Ni elements in different stations. This paper shows that the stations inside the city measured a larger amount of the elements. This can be a result of discharging large amounts of domestic and industrial waste water to this part of the river. Rates of the elements in Goharrood river were found to be over the maximum acceptable rates determined by the department of environment for keeping aquatic organisms alive since Goharrood river is one of the routes for water to enter Anzali wetland, there is a possibility of increased biological risks in fish and human bodies.