Chemical and Physical Alteration of Water after Aquaculture Practice in the Kor River Tributary, Fars Province, Iran

The materials added to the water from fish farms affect the water quality, as these are decomposed in the environment and may reduce the quality of the water so that it is not suitable for further use. Therefore, it is necessary to measure how water quality changes. The impact of the fish farms on the water in the Joobkhalleh River was investigated. Five sampling stations were selected before flowing into the farm, the outlet, and in 5, 8, and 10km after the farm, to be sampled 6 times in 2-month intervals in the spring 2015-winter 2015 period. DO (annual mean 9.0 mg/L), T (14.5˚C), pH (8.4), TDS (462mg/L), COD (8.1mg/L), [PO4]- (0.2mg/L), and [NO3] (1.3mg/L) did not show significant changes, while oxygen saturation, BOD (1.4mg/L), EC (711µS/cm), TSS (6.0mg/L), [NO2] (0.01mg/L), and [NH3] (0.13mg/L) differed significantly among the stations. Regression analysis proved a significant correlation between the increase with distance from the source for [NO2] (Pearson Correlation= 0.915), TDS (0.878), and EC (0.878). Comparison of the findings with water use criteria shows that most parameters were in the suitable range for aquaculture, except for the TDS, which was far out of the standard, and the ammonia which was slightly higher. Considering the effect of pH, these values for the annual average of ammonia and nitrite are considered toxic for fish farming. In conclusion, the annual average of ammonia and nitrite is toxic at the last point for fish farming due to the water pH; therefore, it is not appropriate to use the water for aquaculture development.