عنوان مقاله [English]
The present study was conducted to assess the concentration of toxic (Cd, As) and non-toxic (Cu, Zn) metals in water and sediments of rivers in the west of Mazandaran province, Iran during cultivation (summer) and non-cultivation (winter) seasons. Thirty-six water and sediment samples were taken from four stations (Safarood, Shirood, Kazemrood, and Sardabrood rivers) with three replicates from April to March 2019 to measure the concentration of elements according to standard techniques by inductively coupled plasma mass spectrometry (ICP-MS). Mean values of total environmental factors at the four stations during winter and summer seasons were as follows: temperature=11.21-16.46 °C, salinity=3.58-6.47 g/L, pH=5.42-5.92, soluble matter=3.52-6.25 g/L, electrical conductivity=6.27-11.12 µ mho/cm, nitrite=0.01-0.03 mg/L, and nitrate=1.37-3 mg/L. The quality of environmental factors was found within the normal range for water quality in Iran for different types of land use: agricultural, industrial, recreational, and hot and cold water fish farming. Mean values of total adsorption of cadmium, arsenic, copper, and zinc were respectively 0.25, 0.77, 11.44, 11.02 mg/L in water samples, and 0.2, 3.83, 20.91 and 59.27 µg/g in sediment samples. The adsorption of all metals was higher at the beginning of the cultivation season compared to the non-cultivation season both in water samples and sediment samples. The adsorption pattern of metals was zinc>copper>arsenic>cadmium. Safarood river was the most polluted of all rivers. Compared to Iranian and world standards, the concentration of metals was higher than the permissible limit in water, but lower in sediments (except for copper and arsenic) in all four rivers.