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This work was carried out at Sakha Agriculture Research Station, Kafr El-Sheikh, Egypt during the 2010 and 2011 cotton growing seasons to evaluate the effectiveness of imidacloprid and thiamethoxam, used separately as seed treatments and foliar applications at the recommended rate against the sucking insects: thrips, thrips tabaci (lind), jassid, Empoasca spp., whitefly, Bemicia tabaci, and cotton aphid, Aphis gossypii (Glover.). The side effects of both insecticides on soil fauna was investigated as well. The experimental results showed the following trends: Seed treatment with imidacloprid and thiamethoxam protected cotton seedlings from thrips for at least 6 weeks from the onset of seed planting. Also, both insecticides induced a fast initial effect (after one week of treatment) on whitefly (immature stages). This fast initial effect then gradually decreased to reach a moderate effect according to the general mean of percent reduction. The two tested insecticides exhibited a moderate initial reduction in the population of whitefly (mature stages) and jassids during the two seasons and then this gradually decreased. Imidacloprid had a better efficiency against this sap sucking pest than thiamethoxam. Treatments with imidacloprid and thiamethoxam as foliar applications were highly effective against aphids, up to 14 days in the case of jassids, while the effect was moderate on the whitefly population (mature and immature stages). Imidacloprid had more initial and residual effect than thiamethoxam against jassids. For all soil arthropod groups implicated in this investigation, the used pesticide and depth, significantly affected their mean numbers. The least number of soil arthropods was sampled from the 10-20 cm layer treated with pesticides compared with the 0-10 cm layer. The control plot at both depths recorded the highest number of soil arthropods sampled. Collembola was most abundant while Psocoptera, Oribatida, Actinedida, and Gamasida were least abundant. Pesticide application increased the overall Collembola density compared to the control plots, while it decreased overall Psocoptera, Oribatida, Actinedida, and Gamasida density compared to the control plots. In case of the foliar treatment, there was a reduction in the mean number of examined micro-arthropods either under plants or between plants, in both depths. The reduction in the number of soil arthropods was significantly more in the 0-10 layer. The reduction was more significant between plants than under plants. The most influenced micro-arthropod was Oribatida. The results also revealed that imidacloprid had more adverse effects on soil fauna than thiamethoxam.

Adult male albino rats were fed on stored wheat grains (Triticum aestivum L.) treated with malathion and spinosad at both 8 and 16 ppm for 90 consecutive days to evaluate their hepatic and renal toxicity. The activity of serum acetylcholinesterase (AChE) was decreased in rats treated with the higher concentration of both tested pesticides. Biochemical parameters of liver functions [i.e., aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), acid phosphatase (ACP) activity, as well as total protein, albumin, bilirubin and cholesterol levels] were severely affected especially at higher concentration. Malathion and spinosad elevated the activity of ALT, AST, ALP and ACP in rats treated with the higher concentration. Also, total and direct bilirubin levels increased in rats treated with the higher concentration of both pesticides. On the contrary, both pesticides decreased total protein and albumin levels in treated rats in a concentration-dependent manner. Furthermore, malathion was found to be hyperglycemic. Kidney function parameters (i.e., urea and creatinine levels) were increased in treated rats in a concentration-dependent manner. The above mentioned effects were supported by histopathological examination of liver and kidney tissues. The obtained results indicated also that malathion was able to cause a more pronounced hepato-and renal toxicity in rats than spinosad.

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Diuron contamination of water is a general concern because of the pesticide's toxicity and persistence in the environment. Thus, TiO 2 -facilitated remediation of water contaminated with 1 mg•L -1 diuron was studied using a solar simulator, and under various pH conditions and photocatalyst concentrations, and with the addition of electron acceptors besides molecular oxygen. The effect of a combined TiO 2 /photo-Fenton process was also investigated. Diuron degradation rates were found to be strongly affected by all of the above parameters. Degradation rates increased with increases in pH from 5-9, and decreased when the pH was increased to 11. The degradation rate of diuron increased with increases in TiO 2 photocatalyst concentrations, up to a maximum concentration of 1 g•L -1 . The decrease in total organic carbon due to diuron mineralization was clearly higher when the combination of TiO 2 and peroxydisulfate (10 mM) was used, when compared that obtained with TiO 2 alone and TiO 2 with hydrogen peroxide (20 mM). The combined solar TiO 2 /photo-Fenton process was the most effective method for both degradation and mineralization of diuron in water. Eight kinds of intermediate products from diuron degradation were identified by GC-MS analysis.

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The degradation behavior of the pesticide Irgarol 1051 in pure (Milli-Q) and river water samples in response to photolysis and Fenton reactions was investigated and the hydroxyl radical (•OH) formation rate was determined. Irgarol photolysis was found to occur at a much slower rate in both types of water in terms of the half-life (t1/2) and degradation rate constant (k). Prolongation of photolysis did not lead to complete degradation, even after 480 min. Conversely, Irgarol was rapidly degraded in pure water at pH 3 after 12 and 16 min of irradiation via the photo-Fenton reaction (Fe2+/H2O2/UV-Vis) and photo-Fenton-like reaction (Fe3+/H2O2/UV-Vis), respectively, because of the generation of additional •OH. Irgarol was also completely degraded by the Fe2+/H2O2/UV-Vis and Fe3+/H2O2/UV-Vis reactions in river water at pH 3 after 60 min, while it disappeared after 180 min of irradiation by the Fe2+/H2O2/UV-Vis reaction at pH 5. The photodegradation rates of Irgarol in pure and river water were consistent with the •OH generation rates in both types of water. Mineralization of 96.9 and 92.9% of the Irgarol was achieved in pure water at pH 3 after 16 h of irradiation by the Fe3+/H2O2/UV-Vis and Fe2+/H2O2/UV-Vis systems, respectively. Overall, these results indicate that photo-Fenton reactions are useful for treating Irgarol-contaminated water.

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