Study of toxicological sensitivity of three aquatic organisms representing the three major groups of fresh water Zooplankton (Cladocera, Copepoda, Rotifera) to the insecticide Chlorpyrifos

Acute toxicity of the pesticide Chlorpyrifos tests were conducted to determine the Lethal concentration LC50 during 48 hours exposure on three species of fresh water Zooplankton: Brachionus calyciflorus ( Rotifera), Mesocyclops leuskarti (Copepoda)and Daphnia magna ( Cladocera). • It was found that the species Daphnia magna is the most sensitive to the pesticide Chlorpyrifos as the value of 48h-LC50=1.28 μg/L, followed by the species Mesocyclops leuskarti 48h-LC50=28 μg/L while it was observed severe lack of sensitivity of the species Brachionus calyciflorus to the pesticide 48h-LC50=910 μg/L. • Depending on the values of the units of toxicity TU has been shown that the toxicity of the pesticide Chlorpyrifos is from the fourth level = highly toxic (TU = 78.30) for Daphnia, and Level III = acute toxicity (TU = 3.57) for Mesocyclops, while it is the first level = non toxic (TU = 0.11) for Brachionus. • Each increase in the concentration of the pesticide 1.0μg/L lead to increase the mortality rate in the species studied about: Daphnia magna ، % 68.79 Mesocyclops leuskarti ، % 0.22 Brachionus calyciflorus % 0.0468 As a result, we can expect that the arrival of the pesticide to aquatic ecosystems will affect the whole bio-community in these ecosystems and the inter their relationships, which in turn could be the cause of the disruption of the ecological balance with vague consequences that are difficult to understand its dimensions.

Laboratory Study of Impact of some Insecticides and Balanced Fertilizer in a Number of the Soil Fungi that used as Biological Control Agents

A Study was carried out to evaluate the impact of some insecticide. The results showed that no effects on growth of the studied fungi were observation when Deltamethrin and Chlorpyrifos were used by the low concentration.