|
:
|
Reservoir dams are considered as a water distribution access and as a valuable resource in aquatic production. To conduct limnology studies on the reservoir dam of Qasr e Shirin of the reservoir dam, due to Lake area, 3 sampling stations were selected inside the reservoir dam from August 2017 to August 2018 (one year) in three depths of surface, 5, 10 meters and a station in water supply channel. Non-biological parameters including air and water temperature, dissolved oxygen, pH, Nitrite, Nitrate, Orthophosphate, total alkalinity, electrical conductivity, carbonate, iron, sulfate, BOD5, COD, TOM and TSS were measured according to standard methods of American Public Health Association. Heavy metals of copper, zinc and iron were measured with ICP by USEPA standard method. Also, agricultural pesticides were measured by gas chromatograph (GC). Biological conditions of Qasr e Shirin reservoir dam were measured by identification of biological factors including phytoplanktons and zooplanktons at three depths of surface, 5 m and 10 m of water column. Lake sediments were collected by grab sampler and fixed at 3 stations with 3 replicates. Results of water temperature, dissolved oxygen and pH of different times and depths, showed significant difference in spring in comparison with other seasons. Physicochemical factors analysis of water including Ammonia, Nitrite, Nitrate and Phosphate were observed in the range of Sturgeon aquaculture. Also, low levels of BOD5 (max 12 mg/l) were considered the optimal biological oxygen demand condition. The results showed that the amount of TOM in Qasr e Shirin Lake indicates the high load of organic matter in the lake bottom. On the other hand, the benthic organisms were not observed in the lake which seems that, this is a reason for increasing of TOM in the sediments which not enough consumer is available for organic residuals. Absence of benthos in the sediments might be the advantage of low levels of oxygen in the bottom of lake. Evaluations showed that sustainable development of aquaculture activities would be followed in Qasr e Shirin city in order to reserve local requirements by environmental considerations.
|