Cattle egrets as pesticides biomarker of environmental pollution in Kafr El-Sheikh governorate

الملخص EN

The present study was conducted on cattle egret (Bubulcus ibis) as it was noticed a high incidence of mortality of it in a residential agricultural area, due to exposed to pesticide application (monocrotophos, thiobencarb, fluroxypyr and butachlor) in Kafr El-Sheikh Governorate.

This work was schemed to emphasize the main cause of toxicity induced by pesticides as well as some heavy metals as predisposing cause.

In this study 32 adult (o.3-o.5kg) alive cattle egrets exposed to these pesticides and 8 birds from pastures non-exposed to pesticides acted as controls for comparison, were caught and examined for blood picture and blood biochemistry.

Also, pesticide residues and some heavy metals were determined in mud or soil, internal organs (liver, kidney, brain, ovaries, and testes) and tissues of muscles, skin and feathers of contaminated birds.

Birds exposed to pesticides showed anemia which manifested by a marked drop in RBCs, Hb content and PCV % as a result of disturbance in haemopoietic system.

Meanwhile, leukocytosis, neutrophil a, monocytosis and lymphopenia were recorded in polluted birds which reflect disturbance in immune system in response to intoxication.

However, basophils, eosinophil's showed non-significant variation compared to controls.

Elevation levels of AST, ALP and uric acid were observed in serum of polluted birds in comparison to control values, indicating the hepatorenal dysfunction.

Nevertheless, serum values of ALT and crea-tinine did not alter.

Considerable pesticide residues were measured in mud and examined organs and tissues of contaminated birds.

For exception, thiobencarb and butachlor could not be detected in the testes.

The concentration levels of some heavy metals (pb, Cd, Cu, Zn, Mn, Ni) were determined in mud, organs and tissues of polluted birds.

Pb, Zn and Ni showed the overall concentrations followed by Cu and Mn.

Whereas, Cd levels could be detected only in kidney and brain, while Mn was found in liver only.

It is concluded from the current study that pesticides exhibited rapid deleterious effects on exposure cattle egrets which implicated significantly impairing function of liver and kidney as well as overt disorders in hsaemopoietic system as compared to respective controls.

Despite of some heavy metals as well as bio concentration of pesticide residues in organs and tissues reflect continuous toxicity.

It’s inferred that the mortality of wild cattle egret is a biomarker of environmental pollution by pesticides.