Influence and persistence of phorate and carbofuran insecticides on microorganisms in rice field

An experiment was conducted in microplots (4 m x 4 m) with two insecticides, phorate and carbofuran at rates of 1.5 and 1.0 kga.i.ha(-1) respectively, to investigate its effect on the population and distribution of bacteria, actinomycetes and fungi as well as the persistence of the insecticidal residues in rhizosphere soils of rice (Oryza sativa L., variety IR-50). Application of the insecticides stimulated the population of bacteria, actinomycetes and fungi in the rhizosphere soils, and the stimulation was more pronounced with phorate as compared to carbofuran. Both the insecticides did not have marked effect on the numbers of Streptomyces and Nocardia in the rhizosphere soils. However, the growth of Bacillus, Escherichia, Flavobacterium, Micromonospora, Penicillium, Aspergillus and Trichoderma with phorate and that of Bacillus, Corynebacterium, Flavobacterium, Aspergillus and Phytophthora with carbofuran were increased. On the other hand, the numbers of Staphylococcus, Micrococcus, Fusarium, Humicola and Rhizopus under phorate and Pseudomonas, Staphylococcus, Micrococcus, Klebsiella, Fusarium, Humicola and Rhizopus under carbofuran were inhibited. Both the insecticides persisted in the rhizosphere soil for a short period of time and the rate of dissipation of carbofuran was higher than that of phorate in the soil depicting the half-life (T1/2) 9.1 and 10.4 days, respectively.     

Multiple antibiotic resistance patterns of rhizospheric bacteria isolated from Phragmites australis growing in constructed wetland for distillery effluent treatment

Susceptibility patterns of 12 different antibiotics were investigated against rhizospheric bacteria isolated from Phragmites australis from three different zones i.e. upper (0-5 cm), middle (5-10 cm), lower (10-15 cm) in constructed wetland system with and without distillery effluent. The major pollutants of distillery effluent were phenols, sulphide, heavy metals, and higher levels of biological oxygen demand (BOD), chemical oxygen demand (COD) etc. The antibiotic resistance properties of bacteria were correlated with the heavy metal tolerance (one of distillery pollutant). Twenty-two species from contaminated and seventeen species from non-contaminated site were tested by agar disc-diffusion method. The results revealed that more than 63% of total isolates were resistance towards one or more antibiotics tested from all the three different zones of contaminated sites. The multiple-drug resistance property was shown by total 8 isolates from effluent contaminated region out of which 3 isolates were from upper zone, 3 isolates from middle zone and 2 isolates were from lower zone. Results indicated that isolates from contaminated rhizosphere were found more resistant to antibiotics than isolates from non-contaminated rhizosphere. Further this study produces evidence suggesting that tolerance to antibiotics was acquired by isolates for the adaptation and detoxification of all the pollutants present in the effluent at contaminated site. This consequently facilitated the phytoremediation of effluent, which emerges the tolerance and increases resistance to antibiotics.     

Environmental geochemistry of higher radioactivity in a transboundary Himalayan river sediment (Brahmaputra,Bangladesh): potential radiation exposure and health risks

Environmental Science and Pollution Research - This study of a downstream segment (Brahmaputra, Bangladesh) of one of the longest transboundary (China-India-Bangladesh) Himalayan rivers reveals...     

Mechanistic insights to lactic and formic acid toxicity on benthic oligochaete worm Tubifex tubifex

Environmental Science and Pollution Research - Lactic and formic acid are two commonly found monocarboxylic organic acids. Lactic acid is discharged into the water bodies as acidic industrial...     

Triphenyl methyl phosphonium tosylate as an efficient phase transfer catalyst for ultrasound-assisted oxidative desulfurization of liquid fuel

Environmental Science and Pollution Research - The novel phosphonium-based ionic liquid (IL), triphenyl methyl phosphonium tosylate ([TPMP][Tos]), has been synthesized and applied as a phase...     

Medicinal plants: Potential for economic development in the state of Uttaranchal,India

The present study deals with the medicinal plant wealth of Uttaranchal state in northern India. A total of 964 medicinal plant species were documented with the help of a literature survey and fieldwork undertaken in the various parts of the state. These medicinal plants were used in curing 135 ailments, with the highest numbers of species being used for treatment of cuts and wounds, followed by fever and diarrhoea. Among the various life forms, herbs were dominant (64%), followed by 20% shrubs and 16% tree species. Taxonomically, Asteraceae was the dominant family, having 87 species of medicinal plants, followed by Fabaceae (58 species), Lamiaceae (49 species), Rosaceae (30 species), Liliaceae (29 species), Apiaceae (28 species), Euphorbiaceae (26 species), Ranunculaceae (26 species) and Orchidaceae (23 species). Such a rich resource base indicates the huge potential for economic development of the state through herb-based industries.     

Bacterial pretreatment enhances removal of heavy metals during treatment of post-methanated distillery effluent by Typha angustata L

A combination of bacterial pretreatment followed by free water surface flow through wetland plants was investigated to determine its effect on removal of heavy metals in bioremediation of post-methanated distillery effluent (PMDE). The bacterial pretreatment was intended to transform the metal complexes and organic pollutants into simpler, biologically assimilable molecules. The 10% and 30% v/v concentrations of PMDE favored luxuriant bacterial growth; the 50% concentration supported less growth, whereas the undiluted effluent (i.e., 100%) supported very little bacterial growth. The use of bacterial pretreatment combined with the constructed wetland system greatly increase the overall bioaccumulation of all heavy metals by the plants compared with the control treatment. However, the integration of bacterial pretreatment of PMDE with the Typha angustata resulted in enhanced removal of Cd (34.02–61.50% increase), Cr (35.90–57.60% increase), Cu (32.88–54.22% increase), Fe (32.50–51.26% increase), Mn (35.99–82.85% increase), Ni (35.85–59.24% increase), Pb (33.45–59.51% increase) and Zn (31.95–53.70% increase) compared with a control that lacked this pretreatment. In addition to the bioaccumulation of these heavy metals, several physico-chemical parameters also improved at the 30% effluent concentration: color, BOD, COD, phenol and total nitrogen decreased by 98.33%, 98.89%, 98.50%, 93.75% and 82.39%, respectively, after 7 days of free water surface flow treatment. The results suggest that bacterial pretreatment of PMDE, integrated with phytoremediation will improve the treatment process of PMDE and promote safer disposal of this waste.     

Health benefits valuation of regulatory intervention for air pollution control in thermal power plants in Delhi,India

This study estimates minimum marginal health benefits (morbidity reduction only) of air pollution control and total health benefits arising from regulatory intervention regarding the adoption of the World Bank emission guidelines (WBEG) for thermal power plants (TPPs) in Delhi. The Industrial Source Complex-Short-Term Version–3 (ISCST3) model has been used to estimate the contribution to air pollution from TPPs. The household health production function (avertive behaviour) has been used to value health benefits of air pollution control. The study revealed that the ambient air pollution due to TPPs is reduced by between 62.17% to 83.45% by adopting the WBEG. Annual marginal benefit due to reduction in exposure to air pollution by 1 μg m^?3 is estimated to be US$0.353 per person. Total annual health benefits for adopting the WBEG for TPPs are estimated at US$235.19 million. This study provides a novel methodology to evaluate health benefits of regulatory intervention.     

Field Evaluation of DRAINMOD 5.1 Under a Cold Climate: Simulation of Daily Midspan Water Table Depths and Drain Outflows1

Abstract: The hydrologic performance of DRAINMOD 5.1 was assessed for the southern Quebec region considering freezing/thawing conditions. A tile drained agricultural field in the Pike River watershed was instrumented to measure tile drainage volumes. The model was calibrated using water table depth and subsurface flow data over a two‐year period, while another two‐year dataset served to validate the model. DRAINMOD 5.1 accurately simulated the timing and magnitude of subsurface drainage events. The model also simulated the pattern of water table fluctuations with a good degree of accuracy. The R² between the observed and simulated daily WTD for calibration was >0.78, and that for validation was 0.93. The corresponding coefficients of efficiency (E) were >0.74 and 0.31. The R² and E values for calibration/validation of subsurface flow were 0.73/0.48 and 0.72/0.40, respectively. DRAINMOD simulated monthly subsurface flow quite accurately (E > 0.82 and R² > 0.84). The model precisely simulated daily/monthly drain flow over the entire year, including the winter months. Thus DRAINMOD 5.1 performed well in simulating the hydrology of a cold region.