الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Members of the order Diptera, or true files, are especially good bioindicators of aquatic environmental conditions because they occupy the full spectrum of habitats and conditions, having an important role in higher trophic levels. Therefore, the midge Chironomus riparius was selected as a test species for the study of the lenthal and sublethal effects of environmental pollutants. They are useful indicators for contamination of the sediments and waters that may have gone unnoticed by routine physicochemical measurements
In 96-h acute water bioassays, chlorpyrifos was the most toxic to C.riparius larvae with an LC50 of 1.23 µg/L, followed by pirimiphos-menthyl and permrthrin (1.72 and 2.16 µg/L). Copper was more toxic then cadmium, with LC50 values of 0.27 and 2.8 mg/L respectively. For 10-d whole sediment bioassays with C. riparius larvae, the same order of toxicity was also observed. Reported LC50 values were 0.06, 0.13, 1.14 µg/g dry wt. for the insecticides chlorpyrifos , pirimiphos-methyl, and permethrin ; 105 and 210 µg/g dry wt. for the metals copper and cadium respectively .
Various biochemical parameters measures in Chironomus riparius larvae, such as AChE , GST , ATPase and MTLP , have already demonatrated a high sensitivity toward environmental pollutants