La rivière «Kadicha»au nord du Liban est soumise à des pressions urbaines, agricoles et industrielles. Enl’absence de station d’épuration, Les eaux usées sont rejetées directement dans le cours de la rivière. Afin d’évaluer la qualité des eaux de surface de la rivière Kadicha, 12 sites d’échantillonnage, ont été sélectionnésau niveau desquels des prélèvementsponctuels des eaux de surfaceont été effectués sur 2 saisons (humide et sèche). Les paramètres physico-chimiques ont étédéterminés: pH, température, conductivité électrique, TDS (solides totaux dissous) et les MES (matières en suspension). Des analyses bactériologiques en coliformes thermotolérants(CTT) et en streptocoques fécaux (SF) ont été effectuéespar les méthodes classiques de filtration sur membrane.Le suivi des paramètres physico-chimiques indique une variation spatiale influencée par les activités anthropiques exercées. En se basant sur le système d’évaluation dela qualité des eaux littorales(SEQ-Eau), il ressort que les eauxdes 2 bras étudiés de la rivière ontune très bonne qualitéchimique. Cependant, les résultats de l’analyse bactériologique indiquentl’existence d’une contamination fécalequi dépasse les normes pour une utilisation d’eau à des fins récréatives et pour l’irrigation avec des risques sanitaires pour la santé humainesurtout au niveau de la plaine côtièrede la rivière. La comparaison des teneurs en microorganismes dela présente étude avec une étude précédente réalisée en 2006 sur la rivière Kadicha, indique une augmentation en ces teneurs. Ceci pourrait être liéà l’augmentation des activités anthropiques et démographiquesdurant la dernière décade.

The problem has been exacerbated by the steady increase in population density and the establishment of the Grand Ethiopian Renaissance Dam. Therefore, preserving the availability and quality of this resource is enormously important. Water quality is affected by a number of factors related to the characteristics of the watercourse and surrounding environment, like soil type, agricultural and industrial activity in the studied regions. Therefore, a comparative study was conducted on water samples collected from eight different locations at west and middle Delta regions from Beheira and Gharbia governorates. The obtained results showed that there are significant differences among the means of sample collection sites and dates, as well as the interaction between studied variables in all studied parameters. Although, most physical and chemical parameters were within standards limits except turbidity and chemical oxygen demand (COD). However, the average values of turbidity, color and pH were convergent in both governorates. While total dissolved salts (TSS) had a higher value (42.2 mg L-1) in the Beheira governorate. In the case of, the remaining studied parameters, the values recorded in Gharbia gov. were higher than the corresponding values recorded in Beheira gov. including COD and UV 245 absorbance, which are associated with organic pollution. Thus, physical and chemical approaches can be used to evaluate the water quality in relevant locations. Further studies based on biological approaches should be also carried out.

Context The application of soil amendments to immobilise pesticide residues is a promising technology for meeting human health requirements, environmental protection and cost-effective remediation. Aims This study aims to evaluate the effect of rice straw biochar (RB), rice straw compost (RC) and their mixtures at rates of 0.5% and 1.0% in pots, on the immobilisation of pesticides (such as atrazine, glyphosate and chlorpyrifos) in contaminated soil, using spectroscopy analysis under grown canola (Brassica napus L.) plants. Methods Determination of immobilisation of pesticide residues by GC or HPLC and chemical properties of RB and RC and adding them at differentrates to the contaminated soil. Keyresults The results showed that the addition of RB or RC alone or their mixtures led to a significant increase in the exchangeable Ca2+ contents, organic matter (OM), cation exchange capacity (CEC), uptake of N, P and K and dry weight of canola plants. Pesticide concentrations decreased with increasing OM, CEC, and exchangeable Ca2+ with the soil amended by RC and RB. The data indicated that adding RB at levels of 0.5% and 1.0% resulted in reductions in chloropyrifos by 43.2% and 63.1%, glyphosate by 32.8% and 77.3%, and atrazine by 21.9% and 72.2%, respectively, as compared to the control. Addition of (RC + RB) at 0.5% gave the highest pesticide immobilisation, followed (RC+RB) at 1.0%. Conclusion These results indicate that the dominant mechanisms of pesticides immobilisation in the alkaline soils amended with RC and RB by FTIR and XRD analysis were π–π interaction, pore filling, hydrophobic effect, H-bonding, degradation as well as improvement of soil properties and dry yield of canola plants. Implications Our results suggested the possibility of adding recycled rice straw in the form of compost or biochar to the contaminated soil to improve its properties, immobilise pesticides and increase its production capacity.

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Aphids, particularly Aphis gossypii Glov., is one of the most-important-pests in squash farms, caused serious losses by sucking plant sap in addition to plant viruses' transmission such as Papaya ringspot virus-W (PRSV-W). The current work conducted to study of the effect of various-systemic-insecticides and mineral-oil against melon-aphid, "Aphis gossypii" and its ability on transmissions of non-persistent-viruses under laboratory conditions. Data obtained showed that the "flonicamid" and "pymetrozine" recorded significantly-reduction in virus-acquisition and inoculations when compared-with control "also" reductions were compared-with mineral-oil applications. On-other-hand, data obtained of insecticide-residues activity and KZ-oil on "PRSV" transmission-rate by "A. gossypii" revealed that flonicamid had significantly higher persistence up to 12 days followed by pymetrozine. The mineral oil experienced a significant increase in transmission rate as its efficacy decreased dramatically on the eighth transmission and twelfth days.

Melon aphid, Aphis gossypii Glov. is one of the most important insect pests infesting squash plants causing severe damage and is responsible for transmitting plant viruses. Among these viruses is, Papaya ringspot virus-W (PRSV-W) which, is a virus with the highest economic impact on cucurbits production. A two-year field experiment (2019 and 2020) was conducted at Kafr El-Sheikh Governorate to evaluate efficacy of three insecticides: Chess 50 % WG (pymetrozine), Teppeki 50 % WG (flonicamid) and Confidor 20 % (imidacloprid) as well as mineral oil (KZ 95 % EC) against aphids and spread of PRSV. The treatments were arranged in a randomised complete block design with three replications. During two seasons, tested compounds significantly reduced population of aphid vector, as well as the incidences of PRSV infections and increased fruit yield compared to control. Mineral oil had little effect on aphid populations but it was the best choice to reduce PRSV spread. Imidacloprid was the most effective insecticide against aphids but it was the least in reducing PRSVspread. Both antifeedant insecticides, flonicamid and pymetrozine significantly reduced populations of aphid and incidences of PRSV but they significantly increased fruit yield. Population of aphid was positively correlated with incidence of PRSV. Fruit yield was also negatively correlated with incidence of PRSV and aphid population. Overall, this work showed that it is possible to increase protection of cucurbits fields against PRSV and other non-persistent viruses by incorporating chemicals with different modes of action such as flonicamid, pymetrozine, and mineral oils.