Status and effect of pesticide residues in soils under different land uses of Andaman Islands, India

Pesticides are shown to have a great effect on soil organisms, but the effect varies with pesticide group and concentration, and is modified by soil organic carbon content and soil texture. In the humid tropical islands of Andaman, India, no systematic study was carried out on pesticide residues in soils of different land uses. The present study used the modified QuEChERS method for multiresidue extraction from soils and detection with a gas chromatograph. DDT and its various metabolites, α-endosulfan, β-endosulfan, endosulfan sulfate, aldrin, and fenvalerate, were detected from the study area. Among the different pesticide groups detected, endosulfan and DDT accounted for 41.7 % each followed by aldrin (16.7 %) and synthetic pyrethroid (8.3 %). A significantly higher concentration of pesticide residues was detected in rice–vegetable grown in the valley followed by rice–fallow and vegetable–fallow in the coastal plains. Soil microbial biomass carbon is negatively correlated with the total pesticide residues in soils, and it varied from 181.2 to 350.6 mg?kg^?1. Pesticide residues have adversely affected the soil microbial populations, more significantly the bacterial population. The Azotobacter population has decreased to the extent of 51.8 % while actinomycetes were the least affected though accounted for 32 % when compared to the soils with no residue.     

Shifting wavelengths of ultraweak photon emissions from dying melanoma cells: their chemical enhancement and blocking are predicted by Cosic’s theory of resonant recognition model for macromolecules

During the first 24 h after removal from incubation, melanoma cells in culture displayed reliable increases in emissions of photons of specific wavelengths during discrete portions of this interval. Applications of specific filters revealed marked and protracted increases in infrared (950 nm) photons about 7 h after removal followed 3 h later by marked and protracted increases in near ultraviolet (370 nm) photon emissions. Specific wavelengths within the visible (400 to 800 nm) peaked 12 to 24 h later. Specific activators or inhibitors for specific wavelengths based upon Cosic’s resonant recognition model elicited either enhancement or diminishment of photons at the specific wavelength as predicted. Inhibitors or activators predicted for other wavelengths, even within 10 nm, were less or not effective. There is now evidence for quantitative coupling between the wavelength of photon emissions and intrinsic cellular chemistry. The results are consistent with initial activation of signaling molecules associated with infrared followed about 3 h later by growth and protein-structural factors associated with ultraviolet. The greater-than-expected photon counts compared with raw measures through the various filters, which also function as reflective material to other photons, suggest that photons of different wavelengths might be self-stimulatory and could play a significant role in cell-to-cell communication.     

Behavioural responses and changes in biology of rice leaffolder following treatment with a combination of bacterial toxins and botanical insecticides

Ingestion of the bacterial toxins Bacillus thuringiensis (Berliner) sub sp kurstaki, neem seed kernel extract and Vitex negundo L. (Lamiales:Verbenaceae) leaf extract to the rice leaffolder (RLF), Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae), resulted in altered leaf-folding behaviour and biology. In laboratory experiments, treatment with plant extracts and bacterial toxins suppressed leaf folding behaviour of C. medinalis. Larvae fed lower doses moulted into progressive instars, but in the late fourth to early fifth instars, spinning behaviour completely stopped, feeding was reduced and larvae regurgitated a sticky, semisolid substance that occluded the tunnel in which the pupae were formed. With the combination of Btk and botanicals, average leaf consumption was decreased by a factor of two even at reduced concentrations when compared with controls. Duration of larval and pupal stages, adult longevity and fecundity were more affected by treatment with the combination of bacterial toxins and both botanicals than by the treatment with the bacterial toxins or botanicals individually. All larvae died in the treatment of bacterial toxins and both botanicals combined.     

Performance of the Button Personal Inhalable Sampler for the measurement of outdoor aeroallergens

No personal aerosol sampler has been evaluated for monitoring aeroallergens in outdoor field conditions and compared to conventional stationary aerobiological samplers. Recently developed Button Personal Inhalable Aerosol Sampler has demonstrated high sampling efficiency for non-biological particles and low sensitivity to the wind direction and velocity. The aim of the present study was to evaluate the Button Sampler for the measurement of outdoor pollen grains and fungal spores side-by-side with the widely used Rotorod Sampler. The sampling was performed for 8 months (spring, summer and fall) at a monitoring station on the roof of a two-storied office building located in the center of the city of Cincinnati. Two identical Button Samplers, one oriented towards the most prevalent wind and the other towards the opposite wind and a Rotorod Sampler were placed side-by-side. The total fungal spore concentration ranged from 129 to 12,980 spores m(-3) (number per cubic meter of air) and the total pollen concentration from 4 to 4536 pollen m(-3). The fungal spore concentrations obtained with the two Button Samplers correlated well (r = 0.95; p<0.0001). The pollen data also showed positive correlation. These findings strongly support the results of earlier studies conducted with non-biological aerosol particles, which demonstrated a low wind dependence of the performance of the Button Sampler compared to other samplers. The Button Sampler's inlet efficiency was found to be more dependent on wind direction when sampling larger sized Pinaceae pollen grains (aerodynamic diameter approximately 65 mum). Compared to Rotorod, both Button Samplers measured significantly higher total fungal spore concentrations. For total pollen count, the Button Sampler facing the prevalent wind showed concentrations levels comparable to that of the Rotorod, but the Button Sampler oriented opposite to the prevalent wind demonstrated lower concentration levels. Overall, it was concluded that the Button Sampler is efficient for the personal sampling of outdoor aeroallergens, and is especially beneficial for aeroallergens of small particle size.     

Emerging pollutants: impact on environment,management, and challenges

Environmental Science and Pollution Research -     

Nitrite pre-treatment of dewatered sludge for microbial fuel cell application

The effect of pre-treatment of dewatered sludge using different nitrite concentrations and pH for microbial fuel cell (MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid (FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390?mV and 153?mW/m², respectively, with the addition of nitrite at 100?mg-N/L and pH?9. Furthermore, it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.     

Laboratory and field evaluation of Metarhizium anisopliae for the control of Dengue vector,Aedes aegypti (Insecta: Diptera: Culicidae)

Biological control at the larval stages of development of mosquitoes is one of the techniques that afford a non-expensive, easy-to-use, and environment-friendly method for mosquito control. In this study, investigations were undertaken on microbial product to develop a strategy to control mosquito larval and pupal population in the lab and field. Highest larval mortality was evident in the lab with LC₅₀ and LC₉₀ at 0.25 and 0.5 at 24?h for Aedes aegypti. In the field study, to kill mosquito larval population resulting in 100% mortality of A. aegypti required 5 days duration. The dose-dependent mortality was calculated using a lethal time of approximately 1–5 days test period. The number of mosquito bites (%) (vectorial capacity) decreased at increasing concentration of fungal insecticide. Data indicate that the fungal pathogen interacting with mosquito larvae controlled mosquitoes in the lab and field.