Soil-to-plant uptake of 137Cs and 85Sr in some Egyptian plants grown in Inshas region, Egypt.

The transfer of 137Cs and 85Sr from soil to different plants has been studied in two successive pot field-grown experiments. Five plant species (Oryza Sativa, Tritichum Vulgares, Vicia Faba, Sesamum Orientale and Trifolium Alexandrinum) were grown in pots with sandy clay loam soil contaminated with varying amounts of 137Cs or 85Sr. The absorption of the radioisotopes was measured in different parts of the plants and their activity concentration was significantly increased with increasing radioactivity of both radioisotopes in the soil. The distribution pattern of the total absorbed 137Cs or 85Sr in different plants after soil contamination shows that the shoots of these plants contained the highest percentage of both radionuclides (65.8-73.8% for 137Cs and 77.3-80.7% for 85Sr) followed by roots (16.4-22.4% for 137Cs and 19.5-21.4% for 85Sr) and finally by grains/seeds (4.9-12.9% for 137Cs and 0.3-1.3% for 85Sr). The transfer factors of 85Sr were higher than those of 137Cs for shoots of the tested plants, and were in the ranges of 2.3×10-2 - 4.8×10-2 and 8.8×10-2 - 2.0×10-1 for 137Cs and 85Sr, respectively. The transfer factors of grains or seeds were significantly lower than those of roots or shoots. Also, the transfer factors of leguminous plants were higher than those of cereal plants. Regarding Trifolium plant, the highest activity concentration of both isotopes was found in the second harvest samples.

Distribution of 137Cs and 85Sr in selected Egyptian plants after foliar contamination.

The transfer of 137Cs and 85Sr from fallout to plants was studied in two successive pot experiments. Five plant species (Oryza Sativa, Tritichum Vulgares, Vicia Faba, Sesamum Orientale and Trifolium Alexandrinum) were grown in pots containing sandy clay loam soil. For simulating foliar contamination, radioactive 137Cs and 85Sr solutions were sprayed once with different activity concentrations gently on the shooting system. After 8 weeks of radioactivity application to the above first four plants and 4 weeks to the last one, the total absorption of 137Cs and 85Sr and their distribution in different parts of the tested plants were determined. Most of the absorbed 137Cs and 85Sr accumulated in shoots with proportions ranged from 70.8 to 81.9% and from 88.9 to 95.0%, respectively for different plants. The absorbed 137Cs and 85Sr by grains/seeds followed that of shoots with values ranged from 11.9 to 19.2% and from 5 to 10.9%, respectively. The percentage of 137Cs absorbed by roots ranged from 6.2 to 10.0% among different plants, while 85Sr in roots of plants was below the minimum detectable activity of the detector. For Trifolium, most of the absorbed 137Cs and 85Sr accumulated in the first harvest (81.9 and 98.6%). The aggregated transfer factors (Tag) of both radionuclides under foliar conditions were to a great extent similar. The average values of Tag factors (m2kg-1) of 137Cs and 85Sr, respectively, in rice grains were 3.4 × 10-4 and 1.6 × 10-4; in wheat grains were 4.2 × 10-4 and 2.1 × 10-4; in bean seeds were 4.9 × 10-4 and 2.6 × 10-4; and in sesame seeds were 2.8 × 10-4 and 1.2 × 10-4. Those Tag factors of grains/seeds were substantially lower than those obtained with straw of the corresponding plant species.

Heavy and toxic metals in staple foodstuffs and agriproduct from contaminated soils.

This article presents basic data on the content of Cr, Fe, Ni, Cu, Zn, As, Cd, Sb, Hg, and Pb in staple foodstuffs and agriproduct grown in Russia (Astrakhan region and the town of Belovo) and Egypt (Helwan region). The dependence of the concentration of metals in agriproducts on the content and chemical form of existence in irrigation water and soils is indicated.

Atmospheric volatile organic compound measurements during the 1996 Paso del Norte Ozone Study.

Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juárez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five sites, three on the US side and two on the Mexican side, during nine intensive operation days when high ozone levels were forecast for the area. Six other sites were sampled to characterize up-wind, down-wind and other emission sources. Samples for determining source profiles were collected for rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuels, and industrial manufacturing in Cd. Juárez and a refinery in El Paso. Most samples were collected in electro-polished stainless steel canisters for determination of C2 to C(10+) hydrocarbons by GC-FID. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites during aircraft flights and analyzed by HPLC. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface, total non-methane hydrocarbon values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning and evening at five vehicle-dominated sites, three in Cd. Juárez and two in El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cd. Juárez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde, acetone and formaldehyde.

Ozone formation in the greater Cairo area.

Ozone formation in the greater Cairo area was studied in 1990 in a 3-week measurement period performed at three sites (Shoubra El-Kheima, Mokattam Hill, Helwan), covering a north-south direction of 27 km, and in 1991, from the beginning of April until the end of October, by measurement of the seasonal variation of ozone at one site at El-Kobba. The sinusoidal shape in the diurnal volume fraction plots with peak values of 120 ppb and daily mean value of 50 ppb throughout the year indicate a substantial contribution of photochemistry to the ozone content of the atmosphere. Ozone is produced predominantly over the industrial area in the north and in the centre of Cairo and transported southward by the prevailing northerly winds. Contrary to many urban areas in Europe and in North America, fairly high average ozone levels of 40 ppb are observed during the night throughout the spring and the summer. This may imply that health hazards and crop damage are higher in the greater Cairo area than in Central Europe.