Assessment of Pollution from Trout Farms (Case Study: Haraz River)

Development of aquaculture and the necessity to comply with environmental standards reveal the need to study the potential adverse effects of this industry. One of the most devastating effects of aquaculture would be water pollution caused by the discharge of untreated effluent from fish farms into the host aquatic ecosystems. Accordingly, the present study was performed to assess the contamination caused by trout farms on water quality of Haraz River in northern Iran.

For this purpose, a total number of 24 physical and chemical water quality parameters were sampled from 15 stations over a one-year period based on the standard methods. The maps of Topography, Geology, Hydrology, Soil, Land use, and access roads of the study area were prepared and studied. Furthermore, the pollutant sources, including fish farming pools, agricultural fields, residential areas, industries, and hot water mineral springs, located within the boundaries of the study area were also identified.  

The results showed that concentration of BOD, NO3-, and PO4 at the stations 7 and 10 was very high. The reason for this can be proximity of several fish farms close to each other. . Moreover, the concentration of DO in the mentioned stations showed a substantial decline that may be due to increased consumption of oxygen due to proximity of multiple fish farms in these stations.

Overall, the results confirm the considerable impact of fish farms on the quality of surface water resources in the study area. This highlights the need to take the necessary management measues to control pollutants from the industry in the from of environmental guidelines and regulations.