الفهرس 
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Abstract
Widespread application of pesticides due to their high bio-accumulation brings a hazardous risk of exposure to mammalian system because of optimum residual level and steady dissipation rate. Several studies have suggested that pesticides cause acute as well as chronic health effects in humans
Generally risk assessment in human toxicology has focused on acute or repeated exposure to single pollutants. However, environmental exposures to multiple pesticides for humans are usually at low levels and for long periods of time. It is generally considered that conventional toxicological methods are not suitable for toxicological evaluation and risk assessment of pesticide sequence, especially at lower concentrations.
The aim of this study to evaluate the toxicological effect of some abroad spectrum pesticides(chloropyrifos, lambada- cyhalothrin and emamectin benzoate) on rats and toxic effect of these pesticides on some parameter of environment [soil microorganism and plant cells (mitosis division in onion tip cells)]
from data presented in this study, it can be concluded that:
Tested pesticides caused a significant reduction in RBCs count and Hb content while it caused increase in WBCS compared to those of untreated check.
Results also showed some variables in liver markers which indicate liver injury in rats producing a significant increase in serum (ALT) and (AST) activities compared to those of untreated group
An induction of oxidative stress was recorded as an evidence of increasing the level of (MD A) in rats orally administrated by tested pesticides (alone or in sequence manner) for 30 days, while it results in significant reduction in CAT and SOD activities and in the level of GSH.
Besides, levels of creatinine were affected in treated rats with all tested pesticides given alone or in sequence manner.
Regarding the results recorded after recovery period, all treated rats with pesticides alone could be regenerated according to biochemical parameter, while in case of sequence manner they showed low recovery in all tested parameter. These may be attributed to the synergistic effect of tested pesticides when used as a sequence menner.
Tested pesticides have also potential to cause genetic damage to the plants. They showed different effect on mitosis division in root tip of Allium cepa Chloropyrifos had the highest effect on different stages there is a positive correlation between the concentration used and the toxic effect.
Concerning total population counts of soil organisms and their sensitivity to tested pesticides, data revealed that field application rate of tested pesticides can increase the total population count of tested organisms.
In general, six different species of microorganism were able to grow in the presence of Emamectin benzoate and Lambada-cyhalothrin but could not able to grow in the presence of Chloropyrifos .
Two species of tested pesticides of tested bacteria and two isolates of tested fungi showed high sensitivity to Chloropyrifos, while two species of actinomycetes showed more tolerance to tested pesticides.
Since, the tested pesticides have been used at recommended concentration and cause the pre mentioned toxic effect, it showed be used carefully indicial application of these chemical essential, and discriminate use of pesticides showed be courage as far as practicable.
More studies can be done to demonstrate the genotoxic effect of pesticides on cell cycle in plant.
Besides, it can be also studied not only the impact of pesticides on the population of organisms but also their microbial activities under the influence of pesticides.