تقييم مستوى العناصر الثقيلة وبيان تأثيرها في بعض المعايير الفسلجية والنسجية لأسماك الكارب في نظم مائية مختلفة

Evaluation of heavy metals level and its influence on some physiological and histological parameters of carp fish in different water systems

Summary:

          The current study included the seasonal changes of some heavy metals concentrations(Cd , Pb, Ni, Zn ,Co)in artificial lakes and drainage canal with effect that on the gills and muscles of adult and finger of carp fish in the lakes and drainages . In the lakes, the temperature was recorded between the highest and lowest values(34.07 -10.50), dissolved oxygen(9.66-6.03) mg/L , biological Oxygen Demand (5.8 – 0.2) mg/L, electrical conductivity recorded( 2931.6- 2070) μsm/cm, total dissolved solids(1480 -1040) mg/L , total hardness (1500-1000) mg/L , calcium (1100.3 – 800) mg/L, magnesium (67.37 – 21.9) mg/L, pH (7.51 – 7.29). In the drainages, the temperature was recorded between the highest and lowest value(35.03-11.00), dissolved oxygen(9.66- 1.61) mg/L, biological Oxygen Demand (5.8-1) mg/L, Electrical Conductivity( 2760.3 – 319.3) μsm /cm, total dissolved solids (1350.3-500) mg/L, total hardness (1300- 800.33) mgcaco3/L, calcium (1301-800) mg/L ,magnesium (67.2mg/L, , PH (7.4-8.4) ). As well as the concentration of trace elements cadmium, lead, nickel, zinc, cobalt under study in lake water recorded (0.4mg/l), (0.09mg/L), (0.04mg/L), (0.08mg/L), (0.06mg/L), respectively .As well as elements recorded in muscles and gills concentrations (0.04-0.03 )mg/kg , (0.048 -0.03 mg/kg, (-0.002 0.015) mg/kg, (0.8-6.6) mg/kg, (0.17-0.27) mg/kg respectively. While in the drainages, the trace elements under study were recorded cadmium, lead, nickel, zinc, cobalt (0.05mg/L), (0.04mg/L), (0.04mg/L), (0.1mg/L), (0.08mg/L), while the elements in muscles and gills were recorded (0.04-0.05 )mg/kg , (0.06-0.1) mg/kg , (-0.015-0.018-)mg/kg , (0.9-7.29 )mg/kg ,(0.03 -0.04 )mg/kg respectively. From the above and when analyzing the results statistically, it was found that there are statistically significant differences at the level of (p<0.05)between the months of the study depending on the different sampling seasons. The results of tests of trace elements(Cd ,Ni) in the lakes were higher than the permissible limits (0.5-80)respectively, while the each elements (Pb ,Zn) recorded a level below the permissible limits (0.3-40) respectively. Whereas elements(Cd, Pb ,Ni) in the drainages recorded concentrations higher than the permissible limits, while the Zn recorded a level less than the permissible limits. In the muscles and gills, it was observed that the concentrations of trace elements ranged within or less than the permissible limits. The current study showed higher levels of liver enzymes(ALP, ALT, AST) in some study seasons As follows, where the level of the enzyme ALP, ALT, and AST) was in the adults of lakes (269, 32, 177) U / L, respectively, and in the drainages, the levels of enzymes were (281, 198, 285) U / L, respectively. The enzymes in finger lakes were (214, 25.97) U / L, respectively, while in drainages they were (247, 52, 70) U / L, respectively. The histological study of liver tissue also showed that in carp fish in the lakes hepatocytes appear intact around the central vein in the hepatic lobule and in a cord that extends radially towards the periphery of the hepatic lobule, and the bile duct appears clearly. While some of carp fish in drainages changes appeared in hepatocytes, by containing pyknotic nuclei, and the tissue showed the presence of ballooning in some, as well as fibrosis to some parts of the hepatic lobule. Some of the observed values of trace elements in the current study in water were higher than the permissible limits and others were within or less than the permissible limits, some of the trace element concentrations in gills were higher than the muscles, and the accumulation of the studied elements and their large concentrations in the liver It led to an increase in liver enzymes in addition to the emergence of tissue changes in the liver. The physiological study of blood is important for observing any change in the physiological state of the fish. Increased levels of liver enzymes indicate possible hepatotoxicity due to metal contamination.