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Water Pollution by pesticides is one of the major environmental problems that observe in the surface water of Gilan province because of increasing usage of pesticide due to agriculture development and resitance pest. Polroud River is one of the most important rivers in the eastern of Guilan. There are vast paddy fields in this catchment and a large amount of the organophosphorous pesticides wich drained to the Caspian Sea. Diazinon is one of the well-known pesticide in this area in order to control of ChiloSuppressalis.In current research, the concentration of Diazinon in water, sediment and Sambucusnigra was analysed, Samples were gathered from five stations during two seasons, spring (June) and summer (July, August)of 2012. The water sampels were extracted by solid phasetechnique and then all extracted samples were analyzed by GC-NPD.Finally,obtained data were analyzed by using ANOVA and T-TEST statistical methods.According to the analysis results, Diazinon concentration was negligible in the water, plants and sediment samples during the spring . The maximum concentration of Diazinon(0/75 (l/ug in water sampels was observed in station 3 at summer.Based on the statistical analysis, there was a significant difference between Diazinon concentration in water, plants and sediment samples in summer.

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Effects of Trout farming wastewater on richness and number of macroinvertebrates were done in Haraz River. Identification and surveying of surface water resources, specially Rivers and streams where are among of strategic resources is so important for optimal management. This study was conducted in Haraz River, Polour region (Mazandaran, Northern Iran) during spring and summer. First (as control) and next stations were selected in nearest distance before farm and 75m after that where output water toward River, respectively. Samples were collected using Surber sampler dimensioned 1^fsq (about 30.5 X 30.5 cm²) and 360µm net. Collected samples were fixed with 4% formalin, isolated, and then by sieving with a diameter of 500µ mesh and identified at a level of order and family using creditable keys. In present study 7 orders of Macrobenthoses were identified. Most effects found on 3 orders of Ephemeropterta, Terichoptera and Plecoptera that known as EPT as sensitive group which decreased and unlike, Chironomidae family were increased, which are resistant to pollution.

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Nitrate and phosphate are of the most important pollutants of surface waters. In this study which is cross-sectional, water sampling is conducted during the winter months of 2012, and spring, summer and the fall of 2013 from five stations along the river Oshmak, and parameters of nitrate and phosphate are being measured and tested through the river water sampling according to the standard method of America. Nitrate and phosphate were measured using light absorption method at a wavelength of 880 nm and by spectrophotometer device, and were expressed in units of milligrams per liter ​​and were compared by standard values of drinking and agricultural water using t- test One-Sample. The minimum and maximum amounts of phosphate and nitrate were 0.13 to 1.15 milligrams per liter and 0.20 to 1.35 milligrams per liter, respectively. Nitrate and phosphate levels have increased from upstream to downstream, due to high area under cultivation of rice around the river and the entry of agricultural wastewater and are in less level than the standard. The results make possible decision making regarding the monitoring and control of river water pollution sources and effective use of it for different consumptions to provide the relevant authorities.