Jalel Bouzid

Fate of selected estrogenic hormones in an urban sewage treatment plant in Tunisia (North Africa)

Estrogenic compounds have been monitored for one year at an urban sewage treatment plant (STP) located in Tunisia, to evaluate their fate and seasonal variations. The concentrations of these compounds were determined in both wastewater and sludge phases by gas chromatography coupled with mass spectrometry (GC-MS). Results showed that the highest removal of all estrogens (≥80%) was observed in summer. Mass balance analysis revealed that biodegradation was the predominant removal mechanism. Moreover, the results showed that the removal efficiency of the studied emerging micropollutants and their concentrations in the solid phase of return sludge were much higher in winter and spring than in summer and autumn. These findings were closely related to microbial activity and the concentration of mixed liquor suspended solids (MLSSs). Finally, the findings can be used to help with the modifications that could be implemented in that STP for the improved removal of estrogenic contaminants.

Determination of Organic Compounds in Landfill Leachates Treated by Coagulation-Flocculation and Fenton-Adsorption

1173 CP 3038. Abstract: The objective of this study was to identify the organic compounds removed from the leachates when treated with coagulation-flocculation and Fenton-Adsorption by gas chromatography coupled to mass spectrometry (GC-MS) in order to identify toxic compounds that could be harmful for the environment or human health. Physico-chemical characterization of the raw leachates (RL) was carried out before and after the aforementioned combined treatment process. The effluent from each stage of this process was characterized: pH, Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), turbidity and Total Suspended Solids (TSS). The organic compounds were determined by GC-MS. The removal of COD and BOD5 reached over 91% in compliance with the Tunisian Standards (NT 106.002-1989), which establishes the maximum permissible limits for contaminants present in wastewater discharges to urbanized streams. The chromatographic analysis from the Adsorption effluent proved that this treatment removed more than 99% of the organic compounds present in the initial sample. The phytotoxicity test showed that combined treatment process allowed a significant toxicity removed (92.2%). The mono (2- ethylhexyl) ester 1,2-benzenedicarboxylic acid persisted, although it is not considered as toxic compound by the NT 106.002-1989) Therefore, the treated effluent can be safely disposed of into the urbanized streams.

Effective degradation and detoxification of landfill leachates using a new combination process of coagulation/flocculation-Fenton and powder zeolite adsorption

AbstractThe aim of this work was to examine the application of an integrated technique that consisted of coagulation/flocculation-Fenton-powder zeolite adsorption methods for the treatment of raw leachates from a landfill site of Bizerte (Northern Tunisia). The coagulation–flocculation process showed a moderate chemical oxygen demand (COD) removal efficiency (RE) (54%) and high turbidity RE (94%). The Fenton experiments suggested that the dosage of 1.2 g L−1 of Fe2+ and 2.8 g L−1 of H2O2 at pH 3 were the appropriate working conditions. Under these conditions, COD value was higher than the legal limits for discharge throughout the local municipal sewage. To achieve a satisfactory removal of pollutants, adsorption experiments were also carried out using 30 g L−1 of powder zeolite. The removal efficiencies of COD, ammonia, iron, and aluminum were 97, 91, 99, and 97%, respectively. The phytotoxicity test showed that combined treatment process allowed a significant toxicity removal up to 90%.

Development and method validation for determination of Deltamethrin residue in olive oil using a reversed-phase high performance liquid chromatography

Olive oil is the most important commodities produced in the Mediterranean region. Due to its significant economical importance, the usage of pesticides in its production is systematic, by using a wide range of plant protection products with a variety of modes of action. As a consequence, monitoring of their residue levels in these products is a necessity. In the present study a reversed-phase high performance liquid chromatography method, with a short sample preparation step, based on acetonitrile extraction is developed and validated in olive oil, with a large scope that includes Deltamethrin as pesticide. Good sensitivity and selectivity of the method were obtained with limits of quantification at 0.2 mg kg -1 . Deltamethrin has recovery rate which is of about 80℅. We confirm also the efficiency of alumina, used as adsorbent in the clean up step, to remove triglycerides and to get a pure extract. The agronomic implementation of this protocol allows us to determine the influence of some parameters on the dose and the period of treatment affecting the detected quantities of Deltamethrin residues in the produced olive oil. Indeed, we prove that the treatment dose should be specific for each case considering the olive variety, the geography of the orchard, and the predicted harvest time to determine the convenient dose of treatment. In addition, the results show that the preventive treatment at the blooming phase, does not lead to the concentration of Deltamethrin residues in the oil as it happens at the lipogenesis phase. Keywords: Clean up, Deltamethrin residues, HPLC, olive oil, dose of treatment I. Introduction Olive oil constitutes an essential ingredient in the Mediterranean meals, and more still, nowadays, we are discovering the multiple therapeutic virtues of this aliment thanks to its richness of antioxidants. Thus, producing countries are stimulated to enhance their export rate since it highly contributes in the national economy. Consequently, the use of agrochemicals and pesticides becomes compulsory to avoid the encountered production losses and in order to attain a higher quantity with a better quality. This issue is constantly subject to environmental debates. Indeed, these agricultural practices are responsible of potential risk for human health and can be a source of contamination for the soil, the micro-flora and the groundwater, leading to the entire ecosystem imbalance. With the emergence of the concept of sustainable development, organic food, and the expected decline of Maximum Residue Levels (MRLs) as those of baby-food, the producers are obliged to provide the external market with an olive oil containing pesticide quantities below the MRLs. These rigorous controls require pesticide residues extraction, purification and then analysis with accuracy. Many studies pointed out the difficulties in the separation of the pesticide molecules from fatty matrix that contains between 98 and 99 % of triglycerides (1), and worse still; the pesticides components are concentrated in olive oil during the processes of its formation and extraction (2). Besides, the oil matrix protects them from any oxidation or degradation phenomena that lead to their persistence even at low levels. Therefore, a crucial clean up method is necessary for a precise separation of the pesticides from oil in order to avoid the co-elution of fats during chromatographic analysis. In fact, high molecular weight lipid (600- 1500) can cause damages on columns that may reduce the resolutions efficiency (3).

Persistence of pyrethroid Deltamethrin and its effects on extra virgin olive oil quality

The use of pesticides in developing countries remains out of control in major cases. Consequently, it is common to find amounts of residues exceeding the Maximum Residue Limits (MRLs). This work intends to assess the persistence of Deltamethrin and its impact on the olive oil quality. Time of sampling and concentration of treatment were varied. Analyses were performed weekly during two months. The results show that Deltamethrin levels in oil of treated plants declined by about 50% after 15 days from insecticide application date (1.6 mg kg - 1) for samples treated with the recommended dose or below. No significant differences in oil physicochemical and nutritional parameters were observed. The sensory evaluation of oils extracted after 2 months did not show significant differences in unpleasant aromatic notes nor defects. Olive oil obtained from samples- where the recommended dose was exceeded - had a slower degradation of the active substance. Moreover, some physicochemical parameters of the latters were influenced and the sensory evaluation revealed some defects. Our results confirm that serious doubts remain about the safety and healthiness of oils extracted from drupes treated with Deltamethrin in developing countries in general, and in Tunisia in particular, where recommended doses are not usually respected. This information could evaluate the real risk in the use of this product for plant

Effects of deltamethrin, dimethoate, and chlorpyrifos on survival and reproduction of the collembolan Folsomia candida and the predatory mite Hypoaspis aculeifer in two African and two European soils

Indiscriminate use of pesticides is rampant in most parts of Africa, but only scanty ecotoxicological data exist for the protection of soil organisms-and these data were usually obtained under temperate conditions, including the use of Organisation for Economic Co-operation and Development (OECD) standard test protocols. In order to assess the effects of 3 commonly used pesticides (deltamethrin, dimethoate, chlorpyrifos) on soil fauna in Africa, noncontaminated natural soils were collected from Nigeria and Tunisia. In addition, 2 common test soils, OECD artificial soil and European (Landwirtschaftliche Untersichungs- und Forschungsanstalt [LUFA]) 2.3 soil, were used in OECD standard reproduction tests. Two microarthropod species, the springtail Folsomia candida and the predatory mite Hypoaspis aculeifer, were exposed in these 4 soils spiked individually with the 3 insecticides. Results show that the collembolan F. candida was more sensitive than the mite H. aculeifer for all 3 insecticides. The toxicity of each insecticide in the 4 soils differed, with few exceptions, by less than an order of magnitude. However, the pattern of toxicity was not consistent, that is, the lowest toxicity was often but not always found in OECD artificial soil. Soil- and pesticide-specific patterns of toxicity to F. candida and H. aculeifer might be related to the physicochemical properties of the soils and thus the availability of the 3 pesticides. Following the rules laid down in the European Union for the registration of pesticides and using standard European exposure scenarios, neither an acute nor a chronic risk of dimethoate and chlorpyrifos can be excluded (with few exceptions) in all 4 soils. Lower risks were identified for deltamethrin. For pesticide used in Africa, an environmental risk assessment based on data gained in tests with at least 1 additional natural field soil, preferably of African origin, should be performed using the same risk assessment principles as in the European Union. Integr Environ Assess Manag 2018;14:92-104.

Growth and Yield of Triticale Plants Amended with Sewage Sludge Under Sub-humid Mediterranean Conditions

Triticale (X Triticosecale Wittmack) is one of the most important crops in the development of forage systems, because of its high yield, good mineral balance and better tolerance to biotic and abiotic stress.

Field Assessment of Sewage Sludge as Sustainable Agriculture Practice

The safe disposal of sewage sludge is one of the major concerns worldwide (Singh and Agrawel 2010). In Tunisia, sewage sludge generation has significantly increased in recent years (245 thousands m3 of dried sewage sludge in 2010 compared to 99 thousand m3 in 2002) and its management is still a significant problem. Among the proposed strategies for sewage sludge management and according to the report of the National Urban Wastewater Treatment Program, agricultural application of sewage sludge remains one of the methods.

Response of Solanum lycopersicum to the Exposure to the Most Used Pesticides in Tunisia

Pesticides of the pyrethroid class, such as deltamethrin, are widely used as insecticides because of their short biodegradation period and their low tendency to accumulate in living organisms.

Effects of Landfill Leachate application on Crops growth and Properties of a Mediterranean Sandy Soil

Physical chemical analysis of the Bizerte’s landfill leachate showed high amounts of ammoniacal nitrogen. Its treatment with combined process of coagulation/flocculation, Fenton and powder zeolite adsorption allowed a treated effluent with low content of nitrogen. The microtoxicity of raw and treated leachate was monitored by LUMIStox and its phytotoxicity was examined by seed germination/root elongation tests using seeds of Lycopersicon esculentum, Lolium perenne, Helianthus annus and Medicago sativa. Seedlings of the three species (Lycopersicon esculentum, Helianthus annus and Medicago sativa) were grown in pots, which irrigated with treated leachate at the median effective concentration (EC50) levels, NPK fertilizer and tap water as a control. LUMIStox tests showed that combined process allowed a significant toxicity removal. Treated leachate played fertilizing effect on plants growth. An increase in median effective concentration from 18% to 25% was observed. However, raw leachate showed lower median effective concentration levels varied between 4% and 5%. Results indicated that plants receiving treated leachate and fertilizer grew better than those receiving water alone. The growth of plants with treated leachate irrigation did not differ significantly from plants treated with fertilizer. Treated Leachate irrigation also improved soil N content. Indeed, soils amended with treated leachate had more extractable N concentration in comparison with control soil.