The sensitivity of two tomato (Solanum lycopersicum L.) cultivars, Rechaiga II and De Colgar, to 50, 80, and 100 ppb ozone (O3) exposures was assessed in fumigation chamber, during 4 h per day over a period of 7 days. The Rechaiga II variety was shown to be sensitive to the dose of 50 ppb, showing chlorotic spots on the adaxial leaf surface and alterations of some physiological parameters. During 1-week fumigation, ozone caused a decrease in stomatal conductance, chlorophylls a and b, total chlorophylls, and carotenoids, although soluble sugars and membrane integrity were significantly increased in fumigated plants compared to controls. This trend was similar for the three pollutant doses used in fumigation. The De Colgar tomato remained asymptomatic.
23 primary schools have been selected in Tiaret city, and the collection of PM2.5 was performed in the morning, afternoon and evening, in the presence and absence of the pupils. The results found have shown a gradient of concentrations of PM2.5 by site typology. Low and average concentrations are recorded in the areas close to forests: 23.32±2.77 µg/m3 and the high concentrations are observed in the sites exposed to road traffic: 33.57±3.27 µg/m3 in winter. However, concentrations recorded in the urban sites are lower in the summer (sites exposed to road traffic: 25.33±2.85 µg/m3, sites close to the forests 23.78± 1.92µg/m3). We also noticed that the dominance of PM2.5 has been observed in the vicinity of the major axes of movement. The dispersion of these particles is illustrated by a detailed maps. The maps present information obtained by hierarchical classification, they aim to answer a need for spatial knowledge of the problem of particulate pollution in urban areas in the city of Tiaret. The hierarchical classification allowed to distinguish three groups of schools: urban, urban highly subject to dense road traffic and schools close to green spaces and forests. The results obtained revealed a high contamination of the atmospheric environment of the city of Tiaret by PM2.5 aerosols, taking into account the results recorded in primary schools. Mass concentration of PM2.5 in the 1st period (autumn and winter) is higher than that of the 2nd period (spring and summer). Indeed, the highest concentrations are recorded in the presence of pupils in winter.
The present work aimed at studying the possibility of decontaminating polluted soil by lead from traffic road, using Hordeum vulgare as a heavy metals hyper accumulative plant. High concentrations of lead stored at the horizons of soil surface (1714.39 ± 512.62 μg g-1), have revealed that the traffic and road infrastructures are important outcomes of toxic heavy metals to the environment. In addition, we noticed that Hordeum vulgare may hold a total of 36.28 ± 14.90 μg g-1, which correspond to 2% of that to of that accumulated in the soil. Importantly, highest values were observed in the roots (18.32 ± 8.38 μg g-1), which means 50,50%, whereas, the rate of heavy metals in the stems and leaves were 10.83 ± 5.86 μg g-1 (29,95%) and 7.71±3.74 μg g-1 (21,25%), respectively. Otherwise, the accumulation of lead was influenced by physical and chemical properties of the soil (pH, cation-exchange capacity CEC, percentage of clay). A high content of lead was observed in the plant at low pH; in contrast, the CEC of the soil and the percentage of clay, positively correlated with plant Pb. However, a strong correlation between soil Pb and plant Pb was noticed. Accordingly, lead uptake by Hordeum vulgare seems to be influenced by its bioavailability in soil.
The objective of this work is to determine and quantify the inorganic compounds of PM 2.5 aerosols; collected using a two-stage Dekati® PM10 impactor; in educational establishments in Tiaret-city "Algeria". It also aimed to follow the dispersion of these particles in sites near the forest, urban fabric and urban sites exposed to dense road traffic, as well as to determine the source of this type of pollution. 23 primary schools were chosen as sampling sites in Tiaret city. The collection of PM 2.5 was carried out in the winter and summer period. The spectroscopic analysis carried out by FTiR-ATR shows that the sulfate ions recorded their maximum in the summer period than in the winter, as well as the nitrate and ammonium ions which do not show a large seasonal difference. The dominant species in urban areas are NO 3 -, SO 4 -2 which due to the presence of a very important source of NOx and SO2 which, by gas-particle conversion, transform into nitrate and sulfate ions respectively. These species present a lower proportion in sites close to the forest. However, the same order of abundance of these ions exists in the two sampling periods. The main sources of NOx in urban sites are combustion phenomena linked in particular to the transport system, which is characterized by very dense traffic in the city's agglomeration.
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