Journal de chimie analytique environnementale

Burning of the soils as a result of the burning of vegetation especially the forests are often due to human activities. Most zones which are affected with burning are arid and semi-arid regions. Libya is one of arid regions in the world because the annual rainfall does not exceed 650 mm per year except in a small area called Green mountain (Aljabal Alakhdar), which is receive an annual rainfall exceed than 400 mm. It is the only wet area in Libya, so it contains forest with plant diversity. This region (the area covered by this study), like any forest area in the Mediterranean region is exposed to encroachments such as burning parts of it to convert trees to charcoal or burning trees and turning them into agricultural land in other parts. Therefore, the aim of this study was to evaluate the effects of burning on the organic matter, chemical macro nutrients: total nitrogen, total phosphorus and exchangeable potassium that following burning in two areas in the Green Mountain, with those exposed to burning compared to those in adjacent unburned areas in one seaboard (Ras alhelal) and one mountainous (Marawah) site. The results of this study indicated that the soils in both sites, regardless of burning or depth fall into the silt loam category texture and the main separated particle size was the silt with low clay contents, also the results indicated that, the fire was not enough to change this texture. In the light of the results obtained, it is clear that soils of both study sites are characterized by low organic matter content. In addition, the results indicate that the average percentage of the organic matter in all layers at the seaboard site was higher than its average percentage in the equivalent layers at the mountainous site. According to the findings obtained from this study, there has been a strong impact of fire on total N especially in the new burnt (mountainous) site, which agrees reasonably well with the degrees of soil organic matter of both burned study sites. The expected way that total N would be lost in these soils by fire is in volatilization and particulate transfer to the atmosphere during burning. The results of total P in soils showed that there was more total P in the upper soil layer in the old-burnt site (seaboard) than the new-burnt (mountainous) site at the same depth. It should be noticed from the data that the amount of total P in the seaboard site was high compared with its amount in the mountainous site. As well the results showed that, exchangeable potassium was very limited probably due to its absence in the parent material of the soils and almost all that there is being absorbed by plants. The results indicate that the highest quantities of the exchangeable potassium were in the uppermost layers in both study sites, were particularly high in the mountainous site compared with the seaboard site and were markedly affected by burning in the top layer of the soil.

Aromatic and aliphatic diamines are one of the main components in polyamides, polyimides, polyurea and polyurethanes. To prepare high performance and well featured materials, attempts is directed to the novel diamine synthesis routes in which soluble thermo-resistant, soluble and easy process polymers are obtained. To solubility improvement and decreasing the glass transition temperature, existing flexible bonds in polymer repeating unit are necessary. These bonds decrease the internal rotational energies. Using heterocyclic rings or introducing of polar functional groups such as amide in the main synthetic polymer chain results in convenient polarity and solubility of polymer. Until now, massive investigations have been conducted to prepare aromatic monomers with high solubility and processing capabilities. In the current study, our main aim is to prepare diamines which are applicable in thermo-resistant polymers including polyamide, polyimide, polyurea and polyurethanes.

The study was carried out to assess the Organic Carbon (OC) and available Nitrogen in the soils of the Teaching and Research Farmlands of Modibbo Adama University of Technology, Adamawa State, Nigeria. Soil samples were collected from three locations to make up nine composite samples at a depth of 0-20 cm and the soil samples were analyzed for particle size distribution, soil reaction (pH), Electrical Conductivity (EC), OC, available Nitrogen, available Phosphorus, exchangeable bases, and Total Exchangeable Acidity (TEA). The soil samples were slightly acidic with a pH mean of 6.26. The textural class of the soil samples varied from sandy loam to loamy and with sand ranging from 75.30-80.30%, silt 7.00-11.30% and clay 12.30-13.30%. The OC and organic matter were recorded low and moderate in the three locations. For sustainable crop production; good soil management practice such as crop rotation, addition of quality crop residue, Organic Manure (OM) and application of organic fertilizer is recommended.

Inhabitants of Orji are still pending on borehole water for drinking water without any treatment. The storage of this water in household containers for a long time as well as the handling might lead to a quality deteriorated and become unsuitable for human consumption. The study therefore evaluated the effect of long storage on pH values as well as determined the total concentrations of Ni, Cd, Cu, Pb and Fe in 10 borehole water samples from Orji. The pH was determined using Jenway 3510 pH meter while Perkins Elmer Analyst Atomic Absorption Spectrophometer was used for heavy metals determination after acid digestion. The results obtained were compared to National Agency for Food Drugs and Control (NAFDAC) and Standard Organization of Nigeria (SON) standard and were chemometrically assessed. The mean concentrations of the studied metals were below standard. pH continually increased with storage but did not exceed the standard range of (6.3/6.5-8.5) set by SON/NAFDAC over 12 weeks. Chemometric assessment such as linear regression analysis revealed positive association between pH values and metal concentration. The association were in the order of significant pH/Fe (0.202)>pH/Cd (0.169)>pH/Ni (0.161)>pH/Pb (0.123) respectively. Spearman’s correlation revealed similar source(s) of contamination of the studied metals except for Fe. Coefficient of Variation (CV) showed low variability (<20). Contamination Factor (CF) showed low contamination (<1), except for Cadmium which showed moderate to considerable contamination. Pollution Load Index (PLI) showed no pollution (<1) while mean WQI revealed “poor quality water” with WQI of 100.5 based on the studied metals. Therefore, precaution should be taken when consuming stored borehole water from Orji.

Produced water is the water produced with oil or gas during well production as a result of different operations. Recently, many Sudanese oil fields suffer from the massive amount of water production; the most water production problems in Sudan were observed in Heglig oilfield. The Heglig oilfield is located in Muglad Basin in the southeast and middle of Block 2 in Sudan. The oil production from Heglig oilfield was reported to have peaked in 2006, however it has been declined now and the water cut was reached 95%. Due to many environmental impacts, several studies were conducted for treating the produced water from Heglig oilfield to be used in irrigation; no work was presented to study the effect of Heglig oilfield produced water on chemical additives for fracturing fluids. However, this work analyzes and treats the produced water from Heglig oilfield and evaluates the possibility of the treated water for the re-using in water base fracturing fluids. Samples were collected from two different ponds in the field and analysed according to the American Public Health Association (APHA) and the results were compared with (National Recommended Water Quality (EPA)) to identify the required treatments for the collected water. The analysis was done in Rheine Waal University of Applied Science-Kamp-Lint fort-Germany. In this study, the effect of produced water from Heglig oil field on fluid formulation was studied as management processes of produced water prior to reuse for petroleum operation (Hydraulic Fracturing and Injection) or to be safe in environment. The pH effect on fluids viscosity was investigated for (6, 7, 8, 9 and 10). The results showed that the cross-linking ability of the fracturing fluid presented that better cross-linking system were achieved with 0.48 g CMHEC at pH of 8 and temperature of 40°C for HEC and 60°C CMHEC.

This study reports the effect of water content variation on the rate of Total Petroleum Hydrocarbon (TPH) removal from a contaminated soil. For this purpose, four samples of the soil with weight of 2 kg were placed in identical beakers. The initial TPH content of the soil sample was 60 g kg-1, and the initial moisture content of the samples was adjusted to 60% of the field water holding capacity of the soil. The process of bioremediation was started by nutrient addition and inoculation of TPH degrading microorganisms to the soil. The water content of the samples was restored to the initial value intermittently by water addition. The frequency of water restoration, however, was different for the samples. For the first sample water was restored every two days, for the second sample every four days, for the third sample every 8 days, and finally for the fourth sample every 12 days. The process was continued for 90 days. Microbial counting showed that the number of total heterotrophic bacterial, and TPH degraders were increased significantly in all soil samples. Quantification of TPH residual in soil showed significant difference between the soil samples. For the soil sample with 2 day water restoration pattern, the TPH content decreased from 60 to 18.6 g kg-1. For other samples the degradation was significantly lower. For the soil sample with 12 day water restoration pattern the TPH content decreased from 60 to 42 g kg-1 during the process. A model was developed to predict moisture variation and TPH removal form the soil as a function of time. The model predicted the experimental reasonably well.

Triclosan is a chlororganic substance used as a bactericide in numerous cosmetics. Intensive triclosan use results in the exposure into the environment; therefore, it is vital to analyze and detoxify triclosan-contaminated wastewater, sludge and soil.

This study investigates two analytical strategies. The first is a rapid and inexpensive electrochemical screening technique based on commercial Screen-Printed Electrodes (SPE), which delivers initial results suitable for field measurements and screening. The second is Gas Chromatography–Mass Spectrometry (GC-MS), which is more sophisticated, accurate and sensitive. This latter method can provide more reliable determination of triclosan, e.g., for suspicious samples. We tested the limits of triclosan detection for different electrochemical methods and compared these to mass spectrometry with and without derivatization of triclosan.

In addition to these analytical techniques, gas phase dehalogenation was used to dechlorinate triclosan. Reductive dechlorination of triclosan occurs efficiently at moderately elevated temperatures (350-550°C) with zero valent iron. In contrast to oxidative processes, reductive dehalogenation leads to harmless and completely dechlorinated products.