Toxicologie environnementale et analytique

Epidemiological studies have found that children living in a pesticide treated farmland have higher risk of developing cancer or other serious health problems. Their exposure to pesticides could be limited by periodic health assessments; however, there are few biomarkers for pesticide exposure. The aim of this work was to examine the effects of chronic exposure to pesticides on hematological and biochemical parameters in farm-resident children compared to urban-resident control children. A cross-sectional study was conducted in 72 farm schoolchildren and 41 controls; a follow-up study was done two years later on 20 participants. The children underwent a clinical examination, nutritional assessment, and blood sampling for complete hemogram and biochemical analysis of liver and renal functions, lipid and glucose metabolism, plasma cholinesterase, thyroid hormones and total antioxidant capacity. A prevalence of malnutrition and undernutrition were found in both exposed and control children. The most important hematological results were thrombocytosis in 48% of farm children, increased mean lymphocyte and monocyte counts, and decreased mean neutrophil counts compared to control. Butyrylcholinesterase activity was diminished in 35% of farm children. Alterations in biochemical parameters were observed between exposed and control groups, however, most of the results were within normal limits, except for the significant decrease in total antioxidant capacity. Follow-up study 2 years later showed normalized platelet and lymphocyte counts, however, decreased neutrophil counts was still observed. This study demonstrates that children living in an agricultural community are exposed to the health hazards of pesticides. Undernutrition and improper dental hygiene affect childrens' overall health status and are likely to increase their vulnerability to toxic effects of pesticides.

In land development, the need for up to date planimetric plans is emphasised. Numerous techniques can be used to produce these plans such as traditional photogrammetry, satellite photogrammetry and terrestrial surveying using total station or Global Positioning System (GPS) techniques. However, for the purpose of this paper, GPS and total station are used together with photogrammetric techniques. GPS was used to establish ground control points for aerial triangulation in photogrammetry. Some selected portions within the campus of Universiti Teknologi Malaysia (UTM) are chosen to carry out this integration mapping [1]. Field surveying technique using total station is always adopted as a traditional method for planimetric plan production and mapping of urban and rural areas. Both the conventional surveying i.e., Total station and photogrammetry could be used for surveying purposes but the accuracy and techniques of each method differs from one another, hence in this project, both techniques are looked at in order to compare and draw some inferences. The main objectives will be to produce planimetric plan of the study area using conventional surveying technique (i.e., total station) and photogrammetric method to perform analysis of the two surveying methods.

This paper describe the seasonal variation characteristics of PM2.5, PM2.5/PM10 and established the multivariable linear regression model of PM2.5 based on the observation during the period of January 1, 2014 to December 31, 2014 in central city of China. It is found that the mean concentration of PM2.5 has obvious seasonal variation characteristics, the lowest value in summer and the higher value in winter and autumn. The daily average mass concentration of PM2.5 in January is 161.93 μg/m3 and the over standard rate is 90 percent which is the annual maximum; the annual minimum in august. The ratio of PM2.5 and PM10 is high ratio of autumn and winter, up to 2.9, the spring and summer is relatively stable trend, the ratio between 0.6 to 0.9. The two multivariable linear regression model of PM2.5: [PM2.5]=-39.241+0.394 × [PM10]+44.253 × [CO]+0.4 × [BPM2.5] and [PM2.5]=-43.979+0.462 × [PM10]+70.083 × [CO]. The former is suitable for short-term prediction, high accuracy, the latter is suitable for long-term forecast. Certain probability model can predict the trend of the PM2.5 to explore the pros and cons of air quality. But there are still many deficiencies, need to further improve.

Ubeji Creek in Delta State, Nigeria is an important source of surface water for residents in Warri area is continually being polluted by the regular introduction of wastes and effluents from industries. The impact of industrial effluent on the physico-chemical properties of Ubeji creek in Warri, Delta State was investigated to determine the quality of the water body as well as the extent of pollution. The data that were used in this study were generated from direct field measurements and laboratory analyses. Results of measured parameters showed variation in pH (7.04-7.22), total hardness (32.75-127.63 mg/l), turbidity (26.18-69.75 NTU), THC (2.61-9.37 mg/l), TDS (78.20-615.30 mg/l), TSS (12.63-13.34 mg/l), COD (12.85-49.10 mg/l), BOD (7.34-15.62 mg/l), EC (158.06-1270.80 μs/cm), DO (3.12-4.37 mg/l), phosphate (<0.01 mg/l), bicarbonate (1.23-17.85 mg/l), sulphate (6.52-37.44 mg/l) and nitrate concentrations ranging from 0.28-39.01 mg/l. The results were compared with the DPR and FEPA permissible limits as well as the WHO allowable limits for potable water. The major sources of pollution were observed to be effluents from the industries and dump sites within and around the creek catchment. This is indicative of the ineffective treatment systems and illegal waste disposal practices. These effluents were observed to have negative impact on the creek’s ecosystem and pose a health risk to several rural communities which rely on the receiving water body as their source of domestic water. In order to improve the ecological status of the creek, waste management practice of effluent treatment and strict enforcement of existing legislation to ensuring compliance.

In this paper, a calcination-leaching method by using CaCl2 and H2SO4 to recover alumina from coal fly ash (CFA) is developed. The process conditions including the parameters of CaCl2 content, calcination temperature and time, acid concentration and leaching time are studied. Heat treatment under 900°C for 1 h of the ash with 80 wt.% CaCl2 significantly enhances the alumina leachability (>96.6%) in comparison with the directing acid-leaching (2.31-4.78%) method. The recovery rate increases dramatically with the increasing of CaCl2 content from 20% to 80%, and a H2SO4 leaching time from 10 minutes to 1 hour as well, but it remains near constantly as the increasing of CaCl2 dosage >80% or acid-leaching time >1 h. The reaction mechanism is studied by X-ray diffraction (XRD) analysis to determine the crystalline phases change. The results indicate that quartz, mullite and amorphous phases have been destroyed after calcination with CaCl2 and transformed to gehlenite, calcium aluminum silicate, andradite, wollastonite and mayenite, which are susceptible to acid leaching. The mineralogical characteristics of roasted clinker indicate that molten CaCl2 can promote the incorporation of Ca into silica and silicates and result in the progressive susceptibility to acid attack. The potential chemical reactions during calcinating and leaching processes are also studied via chemical equations. The reuse and resource of coal fly ash can reduce the environmental impact of ash heap and the heavy metal pollution to the surrounding environment.

Formate drilling fluid is a new type of clean brine drilling fluid system which has been developed from inorganic salt brine drilling fluid system. Currently there are mainly three kinds of format: sodium format, potassium format and cesium format. The laboratory research was carried out to determine the thermal stability of drilling fluid. It was formulated using sodium and potassium format salts, potassium chloride. Formate base mud is solid free system. So, mud cake is thin and resilient, it is conductive to improve cementing quality greatly. Formate base fluids because of their low percent of solid settling. Moreover, the low amount of plastic viscosity these muds help to better hydraulic in the well and better hole cleaning. Hence, drilling penetration rate as an extremely parameter in economic costs are decreased. Environmental pollution of formate salts is dramatically less than recent salts like potassium chloride and sodium chloride. It can be appropriate replacement for these environmental polluted salts.

The aim of the study was to investigate heavy metals concentrations in wheat field soils of Tianjin sewage irrigation region, and evaluate the potential ecological risk of heavy metals pollution. ICP-OES was employed to analyze the heavy metals concentrations in wheat field soils of Tianjin sewage-irrigation region. The grading standard of Tianjin soil environmental quality was used as the assessment foundation for soils and Lars Hakanson’s potential ecological hazards index method was used to evaluate the heavy metals pollution potential ecological risk in soils. The results showed that: Cd concentrations in soils ranged from 0.03 mgkg-1 to 1.17 mgkg-1, with an average value of 0.46 mgkg-1; Zn concentrations in the soils ranged from 62 mgkg-1 to 307 mgkg-1, with an average value of 129.08 mgkg-1. The concentrations of Cd and Zn in the soils exceeded second grade standards of Tianjin soil environment quality, so the soil was polluted. The other heavy metal elements, such as Cu, Pb, Cr and Ni, were all lower than second level of Tianjin soil environment quality standards, meaning that the soil was not contaminated by these heavy metals. The heavy metal concentrations were relatively rich in saline wet fluvo-aquic soil and clayification fluvo-aquic soil. Based on Lars Hakanson’s potential ecological hazards index method, Cd had heavily ecological risk in soils and was the main pollutant, while the other heavy metals had lightly ecological risk. Ecological risk of total heavy metals pollution was moderate. The heavy metals were most likely from wastewater irrigation. The pollutants in the soils came mainly from sewage irrigation. The waste water treatment technology should involve steps to remove heavy metals causing risk to human health.

Since 1929, 2010 flood have been assessed as the most horrible flood. It damaged standing crops over an area of 1.93 million acres. During 2010 floods 80 percent of the population in the flood-affected areas was depending upon agriculture for their livelihood. The floods and flash rains in the country have not only damaged agriculture crops, livestock, fisheries, and forestry, but have also destroyed primary infrastructure such as tube wells, water channels, household storages, houses, animal sheds, personal seed stocks/fertilizers, various agriculture machinery and equipment and many more. It has been estimated that the agriculture sector has experienced the overall damages of about Rs. 429 billion while cropped agriculture had suffered from 89 percent of these damages and losses. Productivity of cotton crop reduced to 11.76 million bales against the expected output of 14 million bales. The damages to livestock sector were estimated as of Rs. 48 billion. Damages to the fisheries were negligible and to the forestry were none. The present study is an attempt to explore the shocking impact of 2010 flood on agriculture. The prices of the basic agriculture inputs- diesel, urea, and pesticides- rose sharply. Diesel prices in June 2010 were 75.7 per liter while these prices reached the level of 94.1 per liter in June 2011. The study also tries to identify where man is consciously involved and where unconsciously -lack of planning, mismanagement, and lack of resources- causing floods. The study also tries to suggest how we can protect Pakistan from such hazards in future.

Water is one of the most important global requirements for every activity in life but if it is polluted/contaminated, then it creates direct problems of alkalinity/salinity/toxicity through irrigation to agricultural farms and affects on the quality and nutritional value of cultivated crops. Water quality of Yatta Canal was studied from January to December, 2015 within Machakos County of Kenya. Twenty sampling stations were selected at an interval of 1 km along this canal and water samples were collected once in a month during the wet and dry seasons to monitor its suitability for irrigation. Annual average values of temperature, pH, total dissolved solids, turbidity, dissolved oxygen, and electrical conductivity show significant (P<0.05) seasonal variation. Annual average chemical concentrations of the water during wet and dry seasons are; Nitrates 13.1 ± 0.47 mg/l vs 4.8 ± 0.13 mg/l; Phosphates 0.02 ± 0.001 mg/l vs 0.02 ± 0.001 mg/l; Potassium 3.8 ± 0.098 mg/l vs 2.8 ± 0.031 mg/l; Sulphates 10.7 ± 0.31 mg/l vs 7.2 ± 0.25 mg/l; Bicarbonates 46.9 ± 1.20 mg/l vs 79.9 ± 2.06 mg/l; Chlorides 14.3 ± 0.59 mg/l vs 2.0 ± 0.10 mg/l; Sodium 14.7 ± 0.436 mg/l vs 17.7 ± 0.200 mg/l; Calcium 5.9 ± 0.124 mg/l vs 8.1 ± 0.058 mg/l; Magnesium 2.2 ± 0.020 mg/l vs 2.9 ± 0.029 mg/l, Sodium Adsorption Ratio 1.30 ± 0.030 me/l vs 1.35 ± 0.020 me/l and Iron 0.49 ± 0.007 mg/l vs 0.64 ± 0.041 mg/l respectively. These chemical parameters also show significant (P<0.05) seasonal variation. Most of the physical and chemical levels are within the permissible limits as recommended by FAO and also by Kenya’s National Environment Management Authority with the exception of turbidity (100.2 NTU) and nitrate concentration (13.1 mg/l) only during the wet season. Based on the results, the canal water is safe for irrigation during dry season.

The study evaluated the atmospheric corrosion of corrugated iron roofing sheets in rural, urban, and marine environments using rain water harvested from roofs of various ages. Corrosion study was based on the weathering processes leading to high levels of sulphate, chloride and nitrate in rainwater in the three areas. Results showed that roofs below one year and 2 years in age were more susceptible to rusting than roofs above 15 years. The mean corrosion rates were higher in marine (Ibeno) ranging between 0.16 × 103 μm/yr and 2.94 × 103 μm/yr followed by rural (Okobo) 0.08 × 103 - 1.88 × 103 μm/yr, and the least was urban (Uyo) 0.031 × 103 μm/yr - 0.79 × 103 μm/yr. Sulphates, nitrates and chlorides were high in the marine environment, which also coincided with the area of gas flare by Mobil Oil exploration activities. Increase in temperature and acid rain formations in this area led to increased acid rainstorm. This could manifest in the erosion of beach and wetland, inundates low-lying areas (Ibeno, Ibaka (James town), Oron, Utan brama, Utan-Effiong and Mbe-Ndoro) flooding and loss of coastal land and mangrove forests. Above all, gas flaring affects atmospheric water quality in which soil, crops, fruits, streams, and rivers are affected.

The present study objectively conducted to analysis the physico-chemical parameters and water quality of Mariout Lake water may be changed by several factors in the last decades as a result of anthropogenic activities. the water samples were collected from five sampling stations during the (June to November 2014-2015). The range of physico-chemical parameters were observed Temperature (15.1-32.6)°C, Conductivity (280-380) μ mhos/cum, Total Dissolved Solid (345 -388) mg/l, pH (7.16-8.6), O2 Sat 33.2-97.8%, Free alkalinity (3.34-6.73) mg/l, Total alkalinity (120-265) mg/l, DO (2.14-5.63) mg/l, BOD (2.6-15.2) mg/l, COD (7.4-15.6) mg/l, Chloride (13.6-33.2) mg/l, Calcium hardness (81.8-146.4) mg/l, Total hardness (100-289) mg/l, Nitrate-nitrogen (7.4-11.1) μM, Ammonia (87.0-234.7) μM, N/P ratio (13.4-32.7) μM and Silicate (14.6-221.9) μM during the study. It was concluded that temperature, pH, total alkalinity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, calcium hardness beyond the prescribed limits of WHO. We found that two identified sources are the main origin of most pollutants in this Lake, namely: El-Kalaa drain and industrial activities in Alexandria City. From the data of water quality index (WQI) and other parameters indicates that site V, EL-Mex Bay is more polluted than the other sites (from El-Umum Drain, El-Umum outlet, El Kalaa and El-Mex Pump station). For the sake of this work it is better first to give a preface about the general characteristics of the whole Mariout Lake, and indicated for the quality of the aquatic ecosystem is of great interest to the entire world. Introduction of different waste products into estuaries and seas especially those in industrial and population centers has lead to significant increase in the level of contamination by different pollutants.

Hydrochemical study of surface and ground water were performed for determining its suitability for drinking, industrial and agricultural purposes. In this study, the evaluation of various physico-chemical parameters such as pH, EC, TDS, bicarbonate and alkali metals (Na, K, Ca and Mg) of the surface and ground water has been carried out in selected sites of Dehradun using advanced analytical techniques. All results were compared with the standard limits as per WHO guidelines for drinking water and were accessed stastitiscally. The deterioraton in the quality of the water could be accounted to rapid urbo-industralization activities, increase in population with change of life style, excess use of chemical fertilizers, pesticides in soil to meet the increasing demand in the market, destroyed the water quality of ecologically rich state of Uttarakhand, India.