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681.
A novel and cost-effective method of sulfosulfuron extraction has been developed using distilled water as an extraction solvent. Using this method, the environmental fate of sulfosulfuron was investigated in soil under wheat crop. Studies were conducted under natural field conditions in randomized block design and herbicide (75% water dispersible granules (WG)) was applied after 24 days of sowing. The rates of applications were 25 and 50 g of active ingredient (a.i.) per hectare. Soil samples were collected at predetermined intervals and analyzed by high performance liquid chromatography (HPLC). The minimum detection limit was found to be 0.001 micro g g(-1). The dissipation of sulfosulfuron followed first-order rate kinetics and dissipated with a half-life of 5.4-6.3 days. After harvest, field soil was used for conducting a pot experiment with bottle gourd (Lagenaria siceraria) as test plants to study the carry over effect of sulfosulfuron. No phytotoxicity was observed to bottle gourd in pot experiment with harvest soil. 相似文献
682.
Singh RB Huber AH Braddock JN 《Journal of the Air & Waste Management Association (1995)》2007,57(4):420-433
A microscale emission factor model (MicroFacPM) for predicting real-time site-specific motor vehicle particulate matter emissions was presented in the companion paper titled "Development of a Microscale Emission Factor Model for Particulate Matter (MicroFacPM) for Predicting Real-Time Motor Vehicle Emissions". The emission rates discussed are in mass per unit distance with the model providing estimates of fine particulate matter (PM2.5) and coarse particulate matter. This paper complements the companion paper by presenting a sensitivity analysis of the model to input variables and evaluation model outputs using data from limited field studies. The sensitivity analysis has shown that MicroFacPM emission estimates are very sensitive to vehicle fleet composition, speed, and the percentage of high-emitting vehicles. The vehicle fleet composition can affect fleet emission rates from 8 mg/mi to 1215 mg/mi; an increase of 5% in the smoking (high-emitting) current average U.S. light-duty vehicle fleet (compared with 0%) increased PM2.5 emission rates by -272% for 2000; and for the current U.S. fleet, PM2.5 emission rates are reduced by a factor of -0.64 for speeds >50 miles per hour (mph) relative to a speed of 10 mph. MicroFacPM can also be applied to examine the contribution of emission rates per vehicle class, model year, and sources of PM. The model evaluation is presented for the Tuscarora Mountain Tunnel, Pennsylvania Turnpike, PA, and some limited evaluations at two locations: Sepulveda Tunnel, Los Angeles, CA, and Van Nuys Tunnel, Van Nuys, CA. In general, the performance of MicroFacPM has shown very encouraging results. 相似文献
683.
Toxic releases from medical waste incineration comprising organic emissions such as polychlorinated dibenzo-dioxin/furan (PCDD/Fs)
and polycyclic aromatic hydrocarbons (PAHs), inorganic emissions and ashes containing toxic metals have been reviewed. Attempts
made by various investigators to reduce/eliminate emissions have also been included. Legislations concerning emission standards
for medical waste incinerators have been discussed. 相似文献
684.
Singh G Gupta SK Kumar R Sunderarajan M 《Environmental monitoring and assessment》2007,130(1-3):173-185
The present study describes the development of empirical models for the prediction of various trace metals i.e., Mn, Cu, Fe,
Zn and Pb found in the leachates generated from the ash ponds of various thermal power plants. The dispersion phenomenon of
these trace metals followed first order reaction rate kinetics. The empirical models for individual trace metals derived from
the lab scale models data correlate well with the real field data with regression coefficients varying from 0.93 to 0.98.
The predicted concentrations of the trace metals varied within ±3% of the observed values in the leachates generated from
the ash ponds of four thermal power plants with standard deviation varying from 0.001 to 0.032. The empirical models derived
from the study can be applied for prediction of trace metals in leachates generated from similar thermal power plants. 相似文献
685.
Singh SB Lal SP Pant S Kulshrestha G 《Journal of environmental science and health. Part. B》2008,43(1):27-33
A fungal strain able to use atrazine (2-chloro-4-ethylamino-5-isopropylamino-1,3,5-triazine) as a source of nitrogen was isolated from a corn field soil that has been previously treated with the herbicide. This strain was purified and acclimatized to atrazine at a higher level in the laboratory. A supplemented N was required to trigger the reaction. Atrazine was degraded at a faster rate in inoculated mineral salt medium (MSM) than non-inoculated MSM. Within 20 days, nearly 34% of the atrazine was degraded in inoculated medium while only 2% of the herbicide was degraded in non-inoculated medium. Degradation of atrazine by the isolated fungal strain was also studied in sterile and non-sterile soil to determine the compatibility of the isolated strain with native microorganisms in soil. The degradation of atrazine was found to be more in inoculated sterile soil than in inoculated non-sterile soil. Cell free extract (CFE) of fungal mycelium degraded about 50% of the atrazine in buffer in 96 hours compared to the control. Four atrazine metabolites were isolated and characterized by LCMS. On the basis of morphological parameters the isolate was identified as Penicillium species. Results indicated that the microorganism may be useful for remediation of atrazine-contaminated soil. 相似文献
686.
Huynh TT Laidlaw WS Singh B Gregory D Baker AJ 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):874-882
Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salix × reichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S. × reichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process. 相似文献
687.
The aim of the present investigation is to assess the impact of cypermethrin on reproductive physiology in catfish, Heteropneustes fossilis during prespawning phase. Results indicate that there is a decrease in the size of gonadotrophic cells with less granulation, pycnosis in the liver, presence of immature oocytes and atretic follicles in the ovaries and gross condensation of spermatogenic cells in testes after cypermethrin exposure at sublethal concentration. The gonado-somatic index (GSI), plasma levels of estradiol-17beta (E2) and 11-ketotestosterone (11-KT) also decreases. The motility of sperm cells is dependent on the dilution (2000 times) and duration of motility is recorded 2min maximally at 90s after post-activation. The dose 0.1 and 0.01ppm is sublethal, while 1ppm is lethal on sperm motility. Results indicate that cypermethrin causes inhibition of reproduction by acting at the hypothalamo-hypophyseal-gonadal axis as is manifest from the histological observations of gonadotrophs along with disruption of follicular wall and spermatogenic cells. Obviously such changes are responsible for decreasing the steroid hormone levels which result in decreasing scale and duration of sperm motility after 45d exposure of cypermethrin in this species. 相似文献
688.
Microbe-induced changes in metal extractability from fly ash 总被引:1,自引:0,他引:1
A low cost and eco-friendly technology to bioremediate toxic metals associated with fly ash dumps that contaminate ground and surface water in and around fly ash settling ponds, was investigated. The impact of augmentation of fly ash tolerant bacterial strains, isolated from Typha latifolia growing naturally on fly ash dumps, was studied for metal extractability. It was observed that most of the bacterial strains either induced the bioavailability of Fe, Zn and Ni or immobilized Pb, Cr, Cu, Cd in the fly ash. However, there were few exceptions also. In case of Ni, eight strains enhanced metal mobility, while others caused metal immobilization. The findings also suggest that metal solublization and immobilization are specific to bacterial strains. While induced bioavailability of metals by bacteria may be used to accelerate the phytoextraction of metals from fly ash by hyper accumulator plants, immobilization of metals can check their migration to water reservoirs and reduce the human suffering in affected areas. Thus, bacteria serve the dual purpose and may result in the microbe- assisted phytoremediation of contaminated sites. 相似文献
689.
Concentrations of hexachlorocyclohexane isomers (alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH) were studied in soils samples collected from a small scale industrial unit of Lucknow associated with lindane production. All four isomers were detected from ten sites and the total HCH isomers in the analyzed samples varied from 53 to 99mgkg(-1). Cluster analysis was performed to group the soil sites in terms of their HCH contamination level. Low alpha/gamma HCH ratios were found and they indicate recent input of HCH. There is an urgent need for the on-site remediation of these contaminated sites in order to prevent the long-term environmental pollution. 相似文献
690.
Effect of sublethal treatment of (40% and 60% of 48 h LC50) of deltamethrin+MGK on phospholipid level and rate of lipid peroxidation in nervous and foot tissue of Lymnaea acuminata were studied. Maximum reduction in phospholipid (24.10%) level and increase in rate of lipid peroxidation (586.8%) were observed in foot tissue of snail exposed to 60% of 48 h LC50 of deltamethrin+MGK 264 for 96 h. Alterations in the levels of phospholipids and rate of lipid peroxidation were time and concentration dependent. Use of MGK-264 with deltamethrin increases the toxicity of deltamethrin and their action on membrane phospholipids and rate of lipid peroxidation. 相似文献