Assessment of non-target toxicity of profenofos insecticide on the aquatic bird; the white egret, Egretta alba

Abstract

Although profenofos is the most commonly used organophosphate in the world, and its residual amounts spread into the environment via air, soil, and water, limited information was found on the toxic effect of this insecticide on birds. Previous toxicological studies on profenofos mainly concentrated on rodents and few studies focused merely on broiler birds. Therefore, this study aimed to assess the toxic effects of profenofos on white egret, Egretta alba. White egrets are water birds (Ciconiiformes: Ardeidae) widely spread in all habitats, viz. wetland, fresh and salt habitats. They feed mainly on fish, frogs, small mammals, reptiles, crustaceans and insects. The aggregation sites of this bird are fish ponds, rivers, marshes and channels. In the present study, the median lethal dose (LD50) was determined. Twenty birds were divided into two groups (ten/group). The first group formed the untreated control, while the second group was treated with (1/50 of LD50) profenofos for 5 consecutive days. The toxicological evaluation was performed by assessing changes in body weight gain, relative liver, kidney weights, and serum biochemical parameters, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine, as well as the histological changes in liver and kidney. Profenofos caused a significant decrease in body weight gain and relative kidney weights. Serum biochemical analysis revealed significant increases in the activities of AST, ALT, urea and creatinine levels in the treated group compared to the control. Histological results of liver tissue recorded several alterations, such as the focal accumulation of mononuclear inflammatory cells, and the expansion of the hepatic sinusoids with nucleated erythrocytes and congested blood vessels. The renal tissue showed marked hemorrhagic areas in cortical and medullary zones, mild focal interstitial nephritis, and pyknotic nuclei in the epithelial lining renal tubules. These results have potential value to increase public awareness about the excessive use of profenofos.