Environmental effects of the cold water fish farms effluents on the water quality of Gamasyab River as their main source of water supply in the west of Iran
Rainbow trout (Oncorhynchus mykiss) is one of the most widely cultivated cold fresh water fish in the world. Gamasyab River, with a length of about 200 Km, is one of the longest rivers of Iran. The aim of this research is to determine the effects of trout farm effluents on this river water. From a total of 24 trout farms in the area, four farms were randomly selected and three sampling stations were chosen at each selected farm. Measured water quality parameters were temperature (T) total suspended solids (TSS) total dissolved solid (TDS) dissolved oxygen (DO) pH, five day biochemical oxygen demand (BOD5) chemical oxygen demand (COD) ammonia nitrogen (NH4 N) nitrate nitrogen (NO3 N) and phosphates (PO4 P) Based on the laboratory analysis, DO in the river water was more than 6 mg/l in all cases. There were significant differences in six variables of T, BOD, COD, NO3 N, NH4 N, and TSS of all water samples taken from the second sampling stations between dry and wet season. The DO concentration in Gamasiab River decreased between the water inlet (first stations) and outlet (second stations) but increased in third station. Trout farm effluents had significant impact on the TSS content of the river. This significant increase in TSS concentrations is expected to have occurred due to cleaning or harvesting activities on any of the farms. The results of the study showed that, in all of season, the amount of TSS in the second stations was not equal to the standards of the Department of Environment Protection (40 mg/L) for discharging into river systems. Keyword: Aquaculture, Cold water fish culture, Gamasyab River, Rainbow trout, Water quality, 1 Department of Environment, Hamedan Branch, Islamic Azad University, Hamedan, Iran, P.O.Box:65181 15743. *Corresponding author's Email: phdmrk@gmail.com 1569 Danesh pajooh et al. Environmental Effects of the Cold Water Fish Farms Effluents on the Introduction River water pollution is a serious problem that mainly results from the human activities within the river basin. Discharging fertilizers, pesticides and other organic and inorganic pollutants are contributed as major causes of the rivers' water quality deterioration. Reyahi Khoram and Nafea (2011) Like in many other countries, the aquaculture industry plays a significant role in the Iranian economy, in terms of employment as well as other conventional economic indicators. The main types of aquaculture activities in Iran are categorized into warm water and coldwater aquaculure. In Iran, the sole species for cold water aquaculture is rainbow trout. Hassanpour et al. (2010) Development and enhancement of the cold water aquaculture industry has been accompanied by an increase in environmental impacts, which is mainly pollution and deterioration of the rivers' water quality. Many researchers had studied the effects of aquaculture pollution effluents on the rivers (Pulatsu et al. 2004; Tanigawa et al. 2007; Manoochehri et al. 2010; Angus Webb, 2012 Fadaeifard et al. 2012; Mirrasooli et al. 2012; Saremi et al. 2013) Effluents from aquaculture systems contain organic matter, nutrients, and suspended solids which directly impacts on oxygen depletion, eutrophication, and turbidity in receiving waters. Such effluents may have a serious negative impact on the quality of the receiving water when discharged untreated (Saremi et al. 2013) The environmental effects of fish farms on the river systems could be the introduction of non native fish species, changing the river course and hydrology as well as discharging polluted water. If fish farms effluents discharge into the environment without treatment, it will have undesirable and harmful effects on the environment. Fadaeifard et al (2012) Regarding the environmental and economic importance of Gamasyab River, the aim of this research is to determine the physico chemical parameters of Gamasyab River water in various regions and further determine the effects of trout farm effluents on the river water. Materials and methods Study area Gamasyab River, with about 200 Km length, is one of the longest rivers in Iran. This river has a permanent regime and its average annual flow rate is about 19.14 cubic meters per second. It should be noted that during recent years, due to droughts and increased consumption of underground water sources, at least 25 30% reduction has happened in river water flow. Pollution sources that threaten the quality of water in Gamasyab River may be classified in to two sections namely non point and point sources. Non point sources pollution consist of agriculturerelated pollutants which are drained towards the river. Point pollution sources are those wastewater which are Iranian Journal of Fisheries Sciences 15(4) 2016 1570 discharged into the river from a specific point such as fish farm effluents and industrial waste water Reyahi Khoram and Nafea (2011) Sampling procedure This research was carried out during 2012 to 2013 in Nahavand Township. Gamasyab River provides the water supply of many fish farms along its course. Four trout farms were randomly selected from a total of 24 trout farms located in this river's basin (Fig. 1) These trout farms receive their required water from Gamasyab River and discharge their effluent directly into the river without any treatment. Three sampling stations were chosen at each selected farm. The first stations were located 50 m upstream from the farms which represents the normal conditions of the river. The second stations were the effluents discharge point of each farm to the river. The third stations were located 200 meters downstream in the river and away from the second stations. The selected farms included Ghezel Danesh Farm (farm 1) at Varayaneh village, Ghezel Zagros farm (farm 2) in Sorkh Kand village, Amiri farm (farm 3) at Moradabad village, and Heidari farm (farm 4) at Dehno Sofla village lands. Sampling was performed three times for each station during dry and wet seasons. On this basis, we had a total number of 12 sampling stations and a total of water 72 samples were taken by grab sampling method for this study. Figure 1: Location of four trout farms were randomly selected on the Gamasyab River in Nahavand Township in Iran. Experimental methods Measured physico chemical water quality parameters were temperature (T) total suspended solids (TSS) total dissolved solids (TDS) dissolved oxygen (DO) pH, five day biochemical oxygen demand (BOD5) chemical oxygen demand (COD) ammonianitrogen (NH4 N) nitrate nitrogen (NO3 N) and phosphates (PO4 P) 1571 Danesh pajooh et al. Environmental Effects of the Cold Water Fish Farms Effluents on the Temperature, dissolved oxygen and pH were measured in situ. The other analyses were conducted according to standard methods APHA (2005) All measurements were replicated three times. Water samples were collected for analysis using clean polyethylene bottles, chilled to 1 4degC in the dark and transported to the laboratory within 6 hours. The data collected from this research was statistically analyzed using SPSS (version 19) Also, excel software was used for drawing graphs. The Kolmogorov Smirnov test (KStest) is one of the useful and general nonparametric methods for comparing two samples. It can be used to study the effect of seasonal variation on water samples that are taken from designated stations. Other comparisons were made using non parametric Kruskal Wallis tests. We considered all differences with p 0.05 to be statistically significant. Linear relationship between variables was investigated using Pearson correlation coefficient. Results Based on field surveying and laboratory analysis the amounts of physicochemical parameters of Gamasyab River water were determined at 12 stations. Average values of the parameters are given in Table 1. DO in the river water was more than 6 mg/L in all sampling dates (Table 1) The minimum value of DO measured in Gamasyab River still exceeded the upper limit of DO concentration (5 mg/L or more for DO) that is recommended by the Global Aquaculture Alliance (Boyd and Gautier, 2000) In dry Season, differences among the stations were significant for BOD and TSS (Kruskal Wallis tests, p<0.05) but not for T, pH, COD, TDS, DO, NO3 N, NH4 N and PO4 P concentrations. The results indicate that in dry Season, trout farms had a significant impact on the BOD and TSS concentrations of Gamasyab River (p<0.05) but changes in T, pH, COD, TDS, DO, NO3 N, NH4 N and PO4 P concentration were not significant (p>0.05) (Table 2) In wet season, differences among the stations were significant for BOD, COD, NH4 N, pH and TSS (Kruskal Wallis tests, p<0.05) but not for T, TDS, DO, NO3 N, and PO4 P concentrations. This means that in wet season, trout farms' effluents had a significant impact on the BOD, COD, NH4 N, pH and TSS concentrations of Gamasyab River but changes in T, TDS, DO, NO3 N, and PO4 P concentrations were not significant (Table 3) Throughout the year, differences among the stations were significant for BOD and TSS (Kruskal Wallis tests, p<0.05) but not for T, pH, COD, TDS, DO, NO3 N, NH4 N and PO4 P concentrations. Iranian Journal of Fisheries Sciences 15(4) 2016 1572 Table 1: Parameters of Gamasyab River water quality. PO4 P Mg/L NO3 N Mg/L NH4 N Mg/L TDS Mg/L TSS Mg/ L COD Mg/L BOD5 Mg/L DO Mg/L TC pH S.P. n St. No Time 0.33 1.10 0.18 278.41 29.16 42.60 6.50 7.75 12.7 5 7.84 M 12 1 During dry season 0.35 0.31 0.10 122.65 9.00 4.38 3.37 1.87 2.50 0.07 S 0.35 1.35 0.20 274.43 56.66 44.10 20.08 7.38 12.7 9 7.81 M 12 2 0.35 0.54 0.10 122.71 7.78 6.80 4.16 1.21 2.32 0.09 S 0.38 0.99 0.16 281.95 41.66 42.50 14.25 7.79 12.9 2 7.83 M 0.35 0.41 0.08 126.52 5.77 4.95 3.74 1.14 2.30 0.07 S 0.35 0.70 0.09 224.83 77.91 11.32 5.33 6.56 8.08 7.82 M