بررسي اثر پساب مزارع پرورش ماهي قزل آلا بر خصوصيات فيزيكوشيميايي آب وغناي تاكسوني جوامع ماكروبنتوز رود خانه زاينده رود

چكيده انگليسي :

The effects of effluent of rainbow trout farm on water quality and macrobenthic invertebrates taxa richness of Zayandeh Rud River Rezvan Hatami E mail mehravar 121@yahoo com March 11 2009 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiN Mahbobi Soofiani Assoc Prof Supervisor soofiani@cc iut ac irAbstractExpansion of aquaculture throughout the world has caused a real concern over farm effluent discharge intorivers and streams among both environmental activists and scientists Similar concerns also exist in Iran asaquaculture sector showing a speedy growth Thus to investigate the environmental impact of fish farmdischarge on Zayandeh Rud River three trout farms namely Dimeh Hojat Abad and Takab with threedifferent production capacities were studied Five sampling stations were assigned to each farm as follows inflow and outflow of the farm plus three stations in the river above the farm as control approximately50 100 meters below the outfall and 1 km downstream of the outfall Impacts of farm effluent on the riverecosystem were investigated by utilizing water physico chemical analyses and macrobenthic invertebratebiomonitoring Biotic indices are suitable to measure changes in benthic communities affected by troutfarm effluent and are reliable in assessing benthic responses to organic pollution Water and benthossamples were collected once every season autumn winter and spring Three water samples from eachstation were collected and analyzed using Standard methods to determine parameters such as temperature DO pH BOD5 COD TSS TDS Ammonium Nitrate and phosphate Benthic samples were collectedusing a quantitative technique with three replicates at each station Metrics calculated for themacroinvertebrate community were taxa richness EPT taxa richness EPT abundance mean benthic density no m2 Hilsenhoff index Shannon and Simpson index Water quality index NSFWQIm was alsomeasured to evaluate water receiving farm effluent Results showed a significant increase in dissolved nutrients ammonium nitrate and phosphate and BOD5 COD TSS TDS Results also indicated a significant decline in dissolved oxygen concentrations DO andpH in outflow in comparison with the inflow NSFWQIm values decreased at outflow station indicatingwater quality deterioration However in general concentrations of measured pollutants at each farm werewithin acceptable ranges Overall values for criteria measured were significantly higher P 0 05 inDimeh farm effluent than other farms This is mainly due to higher biomass of fish raised in this farm Significant correlation was found at 0 01 level between fish production rates and orthophosphate BOD5 COD TSS and nitrate produced in trout farms As for the macrobenthic invertebrate results indicated thattaxa richness EPT taxa richness and EPT abundance were significantly P 0 05 lower in outflow stationscompared to that of inflow especially in Dimeh farm According to finding of the present study influence of the farms effluent on water quality of the river wasinsignificant and negligible This might be due to the self purification capacity of the river and also highwater flow rate of Zayandeh Rud River which dilutes effluent from farms and therefore results inimprovement of water quality by reducing nutrient concentrations at downstream stations Contrary tophysico chemical results benthic community responses were significantly different when comparing theupstream and downstream data from each site Sensitive taxa of macrobenthic were declined compared withupstream while abundance of tolerant taxa such as Chironomidae and Oligochaeta in the station located 50meters after outfall increased Collected data indicated that trout farm effluent has a definite effect on theriver macrobenthic communities suggesting that water quality is reduced in 50 m after outfall and to alesser extent 1 km further downstream We conclude that although richness and diversity of taxa increasefur

حاتمي، رضوان

بررسي اثر پساب مزارع پرورش ماهي قزل آلا بر خصوصيات فيزيكوشيميايي آب وغناي تاكسوني جوامع ماكروبنتوز رود خانه زاينده رود

قزل آلاي رنگين كمان , آلودگي آب , ماكروبنتوز , شاخص زيستي