Determination of Physical and Chemical Properties of Water in the Laasm River in Amol

Over time, the quality of water resources is subject to physical, chemical and biological changes due to natural and human factors. Most of these changes are decreasing trend. Qualitative and quantitative monitoring plays an important role in the sustainable management of river ecosystems. The Lasem River is one of the most important sources of surface water in Amol and is one of the major nutritionists in the river Haraz. In this study, five stations were considered along the river route in terms of accessibility and proximity to agricultural land and rural areas. The samples were taken in the summer and autumn of 1394. Physical and chemical properties were determined in standard methods (T, pH, EC, TS, TDS, TSS, DO, BOD5, NO3, PO4 and FC). The results showed that total solids, biological oxygen demand, nitrate and phosphate ion and fecal coliform have an increasing trend in the river route. The quality of the waters of the Lasm River is significantly lower in the summer than in the autumn. The most polluted station is the fifth station (at the confluence of the Lasm River to Heraz). Comparison of measured quantities with standard values showed that dissolved oxygen at most stations at sampling times was lower than the standard river limits. It is likely that the input of agricultural waste and fish farms and sewage in rural areas could be due to its causes. Comparing other quantities measured with standard values, it can be stated that the river is in good condition