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[en] Effects of acid rain and potassium fertiliser on root uptake of 134Cs and 60Co are presented in this paper. Paragrass (Purpurascens sp.) was grown in clay soil homogeneously contaminated with the radionuclides, and kept in a greenhouse for 45 days. Plants in both fertilised and non-fertilised treatments were irrigated daily with a fixed pH solutions of 4, 5 or 6. Every 15 days plant and soil samples were harvested, and analysed to determine the Soil-to-Plant Transfer Factors (TF) of the shoots (TFSP), rhyzomes (TFSRh) and roots (TFSR). The results show that acid rain had an influence on the TFSP and TFSRh values of young plants. Application of K-fertiliser decreased the TFSP of 134Cs. The effect increased with ontogeny. TF values of 134Cs and 60Co were in the order of: TFSR > TFSRh > TFSR. When compared the two radionuclides in each part, it was found that, for TFSR and TFSRh : 60Co > 134Cs, for TFSP : 134Cs > 60Co
[en] Pakistan is an agricultural developing country. About 68% of the country's population resides in rural areas and is mostly linked with agriculture. Agricultural sector contributes more than 25% to GDP, employees about 45% of the labour force and contributes significantly to export earnings of the country. Energy sector is the major source (80%) of emissions of Greenhouse Gases (GHGs). Agriculture and livestock sectors are also responsible for GHGs emissions. The emissions of GHGs results in acid rain and earth's temperature rise (global warming). The destabilization of the global climate destroys natural ecosystem and increases natural disasters, such as violent storms, floods, droughts etc. The acid rain and these natural disasters affect the agricultural productivity. The study indicates that the agricultural productivity per capita in Pakistan decreased continuously during the last two decades. The paper concludes that due to emissions of GHGs, the agricultural productivity is significantly affected in the country. The government should take concrete measures to minimize the emissions of GHGs for increasing the agricultural productivity and reducing other harmful impacts in the country. This paper presents the review and analysis of the effects of GHGs emissions on the agricultural productivity in Pakistan. (author)
[en] In large urban centers, the toxicity of metal mixtures may be enhanced by physicochemical factors and environmental variables, including pH. Rio Grande, a municipality located in the extreme south of Brazil, has soils with high levels of contamination due to urban and industrial activities and a high prevalence of acid rain events. Previous studies have shown that contact with elutriate of these soils can cause physiological and reproductive changes. Thus, the objective of the present study was to evaluate, through animal experimentation, the effects of a metal-contaminated soil, acidified by hydrofluoric acid at two different pH values (5.2 and 3.6), on the health of offspring of rats exposed during gestation and lactation. Female Wistar rats were gavaged daily for 42 days (gestation and breastfeeding) with soil elutriate contaminated with metals, using solvent with different pH values (6.0, 5.2, and 3.6). The following parameters were evaluated in their offspring: body and organ weight, length, appearance of developmental characteristics, and swimming. Experimental groups in which the progenitors were exposed to the solution at pH 3.6 exhibited a delayed increase in weight as well as motor deficit, with a decreased weight (onset) and length (beginning and end), while exposure in association with soil was an aggravating factor for the damages to the body. Exposure to the solution at pH 5.2 decreased the initial weight of the animals, impaired some parameters of weight development, and caused motor deficit on the 14th day. These novel findings reveal that the exposure of progenitors to environmental stressors can compromise the health of the offspring. Special attention should be given to populations living in areas with high prevalence of acid rain.
[en] Full text : The chemical conversions of organic fuels during the refining processes complex gas mixtures containing hydrogen sulfide generate as a by-product. In accordance with the environmental safety requirements these gas mixtures have to be purified from hydrogen sulfide before use or environmental discharge. As it is known because of combustion gases containing hydrogen-sulfide oxides of sulfide emit into the atmosphere and they combine with water vapors in the air and this process consequently results in pH change of H2SO3 precipitations and acid rains. The processes of purification of gas mixtures being the product of oil refining processes and mainly containing hydrocarbons from hydrogen sulfide by a photochemical method and molecular hydrogen generation have been under this investigation.The model gas mixture under investigation has been prepared at a vacuum plant in the laboratory. During the researches the partial pressure of H2S capable of completely absorbing the given wave-length of the radiation has been first specified. It has been established that temperature and irradiation time have their influence on the progress rate of the processes.At this wave-length hydrocarbons undergo no photochemical conversions. This is manifested with the absence of excitation levels causing dissociation due to radiation absorption at the wave-length used in hydrocarbon gases . The fact that these levels belong to hydrogen sulfide contained in gas mixtures has been experimentally proved.The role of hot hydrogen atoms and the mechanism of the processes under progress within the process of molecular hydrogen generation due to the photolytic decomposition of hydrogen sulfide have been discussed.
[en] In 1984, the Canadian Forest Service initiated a national forest health monitoring program, the Acid Rain National Early Warning System (ARNEWS), to monitor the health of the forest and determine the effects of acid rain and regional air pollutants on the forest. Monitoring is done by personnel of the Forest Insect of Disease Survey, who are experienced in the evaluation of forest health. They assess trees in permanent sample plots for forest damage and identify the causes. Causes of tree mortality are also determined. If damage is found for which no apparent cause is evident, research is initiated to determine the source of the damage. To date, ARNEWS has reported on the health of 18 conifer and 9 hardwood species from across Canada, including areas known to receive some of the highest levels of atmospheric pollution in Canada. Results indicate that there is no large-scale decline in the health of our forests and, where pollution-like symptoms were observed, they could usually be accounted for by natural factors. Tree mortality in these natural stands is also normal. However, the monitoring system depends on being able to recognize damage and to determine the cause. The more easily this can be done, the more efficacious is the system. As our researchers assess the trees, they need to know what all type of damage looks like since many pollution symptoms are easily confused with natural effects. The research done on leaf cuticles should help expand this knowledge base. (orig.)
[en] Using a radioactive multitracer and model acid rain (HCl or H2SO4 solution), batch experiments were performed to examine the pH effect on the adsorption-desorption equilibrium of 16 elements on soils as a model study of an acid rain effect. Kaolin, black soil (original and with organic matter almost removed) and Kureha soil (original and with organic matter almost removed) were used as adsorbents. Characteristic dependence on the pH value of the suspension was observed for the adsorption of the elements on kaolin and the soils. The results of this model study indicate that acid rain decreases the retention of cations, while it increases or does not change the adsorption of anions on soils. Organic matter in soils has a positive effect on the extent of adsorption of most elements investigated. (author)
[en] This research was aimed to study the effects of groundwater and acid rain upon the mobility of radionuclides (Cs-134 and Co-60) in contaminated top soil. Clay soil was homogeneously packed in columns with dimension φ.12.5 cm. * 50 cm.. At the top 5 cm. of the columns, soil contaminated with radionuclides was added with the same consistency. Column were kept standing for 4 months in an artificial water table kept at 3 cm. from the bottom. During this period artificial acid rain with pH3, 4.5 and 6 was applied weekly at the top. Soil samples were taken every 30 days for examination of total and extracable radioactivity. It was shown that with the aide of the rain radionuclide movement down the profile was greater, with Co-60 > Cs-134. However acidity of the rain shown no effect on their movement
[en] The Brazilian sandy coastal plain named restinga is frequently subjected to particulate and gaseous emissions from iron ore factories. These gases may come into contact with atmospheric moisture and produce acid rain. The effects of the acid rain on vegetation, combined with iron excess in the soil, can lead to the disappearance of sensitive species and decrease restinga biodiversity. The effects of iron ore dust deposition and simulated acid rain on photosynthesis and on antioxidant enzymes were investigated in Eugenia uniflora, a representative shrub species of the restinga. This study aimed to determine the possible utility of this species in environmental risk assessment. After the application of iron ore dust as iron solid particulate matter (SPMFe) and simulated acid rain (pH 3.1), the 18-month old plants displayed brown spots and necrosis, typical symptoms of iron toxicity and injuries caused by acid rain, respectively. The acidity of the rain intensified leaf iron accumulation, which reached phytotoxic levels, mainly in plants exposed to iron ore dust. These plants showed the lowest values for net photosynthesis, stomatal conductance, transpiration, chlorophyll a content and electron transport rate through photosystem II (PSII). Catalase and superoxide dismutase activities were decreased by simulated acid rain. Peroxidase activity and membrane injury increased following exposure to acid rain and simultaneous SPMFe application. Eugenia uniflora exhibited impaired photosynthetic and antioxidative metabolism in response to combined iron and acid rain stresses. This species could become a valuable tool in environmental risk assessment in restinga areas near iron ore pelletizing factories. Non-invasive evaluations of visual injuries, photosynthesis and chlorophyll a fluorescence, as well as invasive biochemical analysis could be used as markers.