Abstract
Abstract
The most widely used pesticides for residential areas and agriculture purposes, which belong to the organophosphates and synthetic pyrethroids, were evaluated in this study for their LC0 toxicity. In an aquatic environment, these pesticides are highly toxic to nontargeted organisms. Oreochromis niloticus (Nile tilapia) was selected for the bioassay tests due to its presence in the trophic levels and high bioaccumulation of the toxicants. This study evaluated the impact of pesticides on the activity of alkaline phosphatase (ALP) enzymes in the brain, gills, and muscles of O. niloticus. The fish were exposed to the LC0 concentrations of malathion (1.425 ppm), chlorpyrifos (0.125 ppm), and λ-cyhalothrin (0.0039 ppm) for 24 and 48 h. For biochemical assays, malathion, chlorpyrifos, and λ-cyhalothrin measurements were carried out using spectrophotometry. ALP activity in the brain and gills was elevated and showed significant inhibition (p < 0.05) at 24- and 48-h exposure, respectively. For the muscle tissues, a statistically important (p < 0.05) inhibition was recorded for the activity of ALP after 24- and 48-h treatments. The highest (+138%) and the lowest (+28%) enhancement in ALP activity were reported in the gills and brain tissues, which were treated with chlorpyrifos and malathion, respectively. The minimum and maximum reduction in ALP levels were noted in the 48- and 24-h malathion-treated muscle tissues, respectively. The data for the muscle tissue sample showed good consistency, because inhibition in ALP activity was noted. Therefore, the assessment of ALP activity in different organs and tissues in fish for the detection of chemical hazards in the environment is recommended. These findings confirmed that pesticides should be consistently monitored in the environment, to lower the pollutant stress on nontargeted organisms, especially fish, because the pesticides have a toxic effect on the health of aquatic organisms.