ENVIRONMENTAL STUDIES OF WATER QUALITY AND ITS EFFECT ON FISH OF SOME FARMS IN SHARKIA AND KAFR EL-SHEIKH GOVERNORATES

Abstract

Nowadays, the problem of water shortage is due to the increasing of population, so huge amounts of water are needed for covering the expansion of inland reclamation, fish culture and industrial activities. To find new sources of water, agricultural drainage water is considered one of the most important sources for fish farms. But the pollutants of these activities are increased and discharged directly into agricultural drains. These pollutants effect on physical, chemical and biological characteristics of aquatic ecosystem. To study the quality of the agricultural drainage water sources and its impacts on the water and fish reared in two different farms namely, Al-khashaa, kafr El-Sheikh governorate and Abbassa, Sharkia governorate, Egypt. Moreover, the effect of fish farms on the surrounding water quality, the present study investigated the physical, chemical and biological characteristics, as well as the concentration of some heavy metals of the water supply, ponds water, effluents water of fish farms, and their accumulation in fish organs (muscles, gills and liver). Also the distribution of phytoplankton and zooplankton. Samples were collected monthly from June to December during 2011 from, inlet (El-Gharbia main drain and El-Wady drain), fish ponds and outlet of two fish farms. The obtained results could be summarized as following 1-Physical and chemical parameters. 1.1. Water temperature The water temperature differed during the study period, where the maximum mean value was recorded at ponds (P2, 25.7 and P1, 24.96 oC) and the minimum one was detected at drains (D2, 23.62 and D1, 24.4 oC). Monthly, the temperature varied from 14.28 oC in December, to 32.67 oC in July. There was a highly significant monthly variation in temperature (P< 0.001). 1.2. Hydrogen ion concentration (pH) The pH lies on the alkaline side, with total means of 9.23 and 8.64 in Al-Khashaa and Abbassa fish farms, respectively. The lowest mean value was observed at sites D2 (8.42) and D1(8.99), whereas the highest one was at sites P1 (9.45) and P2 (9.11). There were highly significant spatial and monthly variations in pH (P< 0.001).The minimum pH value was recorded in June (7.52) while the maximum( 9.52 )was during October. 1.3. Transparency The Secchi Disc reading at ponds illustrated that the lowest mean value (P2, 8.11 and P1, 8.27 cm) but the highest one was found at drains (D2, 23.71 and D1,18.27 cm). There were significant monthly and spatial variations in transparency (P < 0.001) .In August the minimum transparency (mean 6.5 cm)was observed, while the maximum mean value was 23.5 cm in June. 1.4. Dissolved oxygen (DO) The total means of DO concentrations were 5.36 and 6.3 mg/l in Al-Khashaa and Abbassa fish farms, respectively. The highest mean value was detected at site P2 (8.11 mg/l) and the lowest one was obtained at site D1 (3.75 mg/l). DO mean value varied from 4.05 mg/l in August to 7.6 mg/l in December. There were significant monthly and spatial variations in DO (P< 0.001, 0.05) respectively. 1.5. Total alkalinity The minimum mean value was at drains and the maximum one was found at site P2(403.8). There were significant spatial and monthly variations in total alkalinity (P< 0.001,0.05) respectively. Monthly, its value in August was 285 mg/l ,while in December reached to 397.5 mg/l. 1.6. Total hardness Total hardness concentration was with total means of 689.5 and 260.03 mg/l in Al-Khashaa and Abbassa fish farms, respectively. The lowest mean value was recorded at site O2 (192.6 mg/l) and the highest value was at site O1(782.9 mg/l). The minimum total hardness was observed in July (151.7 mg/l) and the maximum (966.7 mg/l) was during December. There were significant monthly and spatial variations in total hardness (P<0.001, 0.01), respectively. 1.7. Nitrite Its concentration varied where, the maximum mean value (0.435 mg/l) was shown at site D1 and the minimum was at site P2 (0.077 mg/l). There was significant spatial variations in nitrite (P<0.001). Monthly, the lowest concentration was recorded in September (0.073 mg/l), while the highest one was observed during December(0.41 mg/l). 1.8. Nitrate There was a highly significant spatial variations in nitrate (P<0.001). The total means of nitrate were 2.18 and 1.34 mg/l in Al-Khashaa and Abbassa fish farms ,respectively. The highest concentration was found at site D1 (3.26 mg/l), while the lowest one was at site O2(0.84 mg/l). The minimum mean value concentration was detected during October (0.775 mg/l), and the maximum one was in December and June (2.473 mg/l).