Showing 6 results for Toxicity
A. A. Pourmirza, M. Tajbakhsh,
Volume 6, Issue 3 (10-2002)
Abstract
Due to the need for new fumigants to control insects that attack food commodities, the toxicity of acetone was determined on some species of stored pest insects in Urmia University in the year 2000. In empty space tests, the LC50 values of acetone for Oryzaephilus surinamensis (L.), Callosobruchus maculatus (F.), Tribolium confusum (Duv.) and Sitophilus granarius (L.) were 15.40, 15.51, 17.55 and 18.26 μl/liter, respectively. The experiments of acetone penetration to wheat mass revealed that the application of acetone in headspace led to the penetration of acetone vapours into the wheat mass and killing the S. granarius and T. confusum had been concealed in interkernel space. The comparison of LC50 values of empty space tests with LC50 values of penetration experiments revealed that the increase in penetration toxicity was 8.63 fold for S. granarius. A similar trend was observed for T. confusum adults. In hidden infestation tests, the application of acetone to the headspace resulted in destroying the developmental stages of S. granarius concealed in wheat and achieved 75% mortality at a dose of 160 μl/liter during seven weeks. Acetone showed no deleterious effects on the germination and vigor of wheat seeds.
R. Hajiboland, M. K. Khosrowpanah,
Volume 9, Issue 4 (1-2006)
Abstract
Manganese toxicity occurs in many agricultural and natural ecosystems under the various soil conditions such as the nature of substrate, acidity, flooding or vicinity to the mining areas. The objective of this work was to study the effects of excess Mn in the growth medium on three important crop species, namely rice (Oryza sativa L. cv. T. Hashemi), maize (Zea mays L. cv. SC.704) and sunflower (Helianthus annuus L. Mehr). Plants were cultured in the hydroponic medium under controlled environmental conditions and treated with 0 (control), 25 50, 75 and 100 µM Mn for 12 days. Dry mass production, the effect of supplemental Mg and Ca on the toxicity expression, root respiration and K+ leakage from shoot and root tissues were studied under the Mn treatments. In order to study the effect of light intensity on the expression of toxicity symptoms, plants were cultured under the different light conditions, thereafter their growth and metal uptake and transport were studied. Sunflower plants treated with the 50 µM Mn and higher, showed dark-brown spots associated with the trichomes on the leaves and petioles. Maize plants developed interveinal chlorosis and any visual leaf symptoms was observed in rice. In all of the studied species, a great portion of the absorbed Mn was translocated into shoot, the highest transport was observed in sunflower and the lowest in maize. No significant correlation was observed between the expression of Mn toxicity and the accumulation rate of Mn. Growing under the low light intensity, in addition to the lowering biomass production, increased or decreased the toxicity effect depending on species. Mn-toxicity-induced root respiration was not associated with the differential response of species to Mn toxicity. In contrast the change of K+ leakage from shoot and root tissues was well correlated with the toxicity response of tested plants.
A. Taebi, K. Jeirani, A. Mirlohi, A.r. Zadeh Bafghi,
Volume 11, Issue 42 (1-2008)
Abstract
Some industrial processes, such as plating and gold mining, utilize cyanide, which entering in their effluents. Because cyanide compounds are toxic contaminants, the waste-containing cyanide must be treated before discharge in the environment. Several methods are available for cyanide removal or detoxification. Natural degradation, alkaline chlorination, and oxidation with hydrogen peroxide are the most common methods in full-scale plants. Because of technical and economical concerns related to these methods, biological treatment processes have recently come under consideration. In phytoremediation, plants potential for pollutant removal is used. The main objective of present study is to investigate feasibility and potential of phytoremediation of cyanide-polluted soils by non-woody plants. The experiments carried out in this study were a completely random factorial design procedure, with three replications. Three non-woody plants: sorghum (as a cyanogenic cereal plant) and fescues with and free of endophyte (as grasses), were examined. Analysis of variance of the data obtained on soil cyanide reduction and cyanide accumulation in plants showed that phytoremediation is a suitable technique for low concentration of cyanide-polluted soils. Besides, it was been found that sorghum has a better soil cyanide removal efficiency than fescues, so that a significant portion of soil cyanide will accumulate in sorghum tissues.
H. Koohkan, M. Maftoun, Y. Emam,
Volume 12, Issue 44 (7-2008)
Abstract
Nitrogen (N) is usually low in the majority of agricultural and non agricultural soils in Iran, mainly due to the lack of adequate soil organic matter (OM). On the other hand, boron (B) toxicity is becoming more widespread in arid and semi arid regions of this country, where soils or irrigation waters contain relatively high B content. Results of the research indicate that addition of certain plant nutrients such as N may reduce the harmful effect of high B levels. Therefore, the present experiment was undertaken to evaluate the interactive effect of N and B on the growth and chemical composition of rice in a calcareous soil. Treatments consisted of six B rates ( 0, 2.5, 5, 10, 20 and 40 mg kg-1 as boric acid) and four levels of N ( 0, 75, 150 and 300 mg kg-1 as urea) arranged in a factorial manner in a completely randomized design with three replicates. Application of B decreased shoot dry matter. At low B levels, N application alleviated the toxic effect of B. Moreover, the addition of B increased B and N concentrations in the rice shoot. The N concentration increased and B accumulation decreased with increasing N rates. There was a general trend of increase in shoot N and chlorophyll concentrations with increasing chlorophyll meter reading. Chlorophyll concentration decreased with increasing B levels. N fertilization increased chlorophyll content and somewhat reduced the adverse effects of high B rates on this plant parameter. The results reported herein show that in soils with high B levels, N application may alleviate the suppressing effects of B toxicity and increase rice growth possibly due to a decrease in B absorption by the plant
N. Azadi, F. Raiesi,
Volume 26, Issue 1 (5-2022)
Abstract
Biochar as an efficient strategy for the improvement of soil properties and organic waste management may reduce the potential effects of abiotic stresses and increase soil fertility. However, the effects of this organic amendment on soil microbial indicators under combined salinity and pollution have not been studied yet. Therefore, the objective of this study was to evaluate the influence of sugarcane bagasse biochar on some soil bioindicators in a Cd-polluted soil under saline and non-saline conditions. A factorial experiment was carried out with two factors, including NaCl salinity (control, 20 and 40 mM NaCl) and sugarcane bagasse biochar (soils unamended with biochar, amended with uncharred bagasse, 400 oC biochar, and 600 oC) at 1% (w/w) using a completely randomized design. Results showed that salinity increased the mobility of Cd (12-17%), and subsequently augmented its toxicity to soil microorganisms as indicated by significant decreases in the abundance and activities of the soil microbial community. Conversely, sugarcane bagasse biochar application reduced the concentration of soil available Cd (14-18%), increased the contents of soil organic carbon (89-127%), and dissolved organic carbon (4-70%), and consequently alleviated the effect of both abiotic stresses on soil microbial community and enzyme activity. In conclusion, this experiment demonstrated that the application of sugarcane bagasse biochar could reduce the salinity-induced increases in available Cd and mitigate the interaction between salinity and Cd pollution on the measured soil bioindicators.
F. Beigmohammadi, E. Solgi, M. Soleimani, A.a. Besalatpour,
Volume 26, Issue 3 (12-2022)
Abstract
The industrial areas are located near residential centers in the city of Arak and potentially toxic elements (PTEs) pollution is a serious threat to human health and living organisms in this area. Meanwhile, soil contamination by PTEs is one of the challenges in this region and various studies have been conducted in this area. Meta-analysis studies provide a comprehensive evaluation of the results of a subject. In the present study, soil contamination data for PTEs in the 11 years (2009 to 2020) were studied through the studies conducted in Arak. In this study, the risk, potential toxicity, and carcinogenic and non-carcinogenic risks of PETs were assessed using indices and mathematical relationships. Based on the results of pollution indices, the soil of Arak city in terms of PETs including Zn, Cd, Cr, Ni, As, Pb, Cu, and Hg were categorized into the polluted and highly polluted classes. The soil of the region in terms of PETs has significant ecological risk and acute toxicity. Cadmium, arsenic, and mercury showed the ecological risk of 49.3%, 23.2%, and 18.3% respectively, and nickel, chromium, and arsenic were responsible for 34.7%, 23.03%, and 22.07% of the toxicity potential of PETs in the soil. Arsenic, nickel, and chromium have the highest carcinogenic risk for children in both the ingestion and inhalation pathways, and chromium, arsenic, and nickel have the highest carcinogenic risk from the inhalation pathway for adults. According to the results, the most considerable PETs in the study area including As, Cd, and Pb, and the most important source of their emission in Arak are anthropogenic resources and industries.
