STUDY ON SOME PHYSICAL AND CHEMICAL CHARACTRISTICS OF SHADEGAN MARSH

Sampling in 5 stations was carried out from July 1999 to June 2000. Water temprature, pH and EC were measured on site. Maximum water temprature was observed in July and August, and maximum level of dissolved oxygen occured in November and February. Range of pH was between 7.2 to 9.4, in acceptable range for aquatics. The results showed that Shadegan marsh is a hard and brackish water body. Dissolved oxygen level was more than 5 ppm in most of the cases, and is optimum for fish growth and reproduction. Amount of BOD5 was 3-10 ppm. COD levels showed an increase in Autumn. With respect to N.NO3 and N.NO2, the water could be considered as unpolluted water. According to the statistical analysis of data, Mansoreh and Ataysh stations showed the same water quality. Study in various years showed that water quality in Shadegan Marsh has been diminished, probably due to decreasing run off and increasing pollution in Shadegan Marsh.