Natural Weathering Studies of Polypropylene

Polypropylene (PP) has achieved a dominating position and hence, their consumption increases thereby littering, which lead to environmental pollution. Photodegradation seems to be a better choice because of naturally available sunlight as energy source for degradation. The present work involves the study of the variation of degradation behavior of PP film during tropical summer and winter seasons. The photodegradation is followed by Fourier transform infrared (FTIR) spectroscopic technique. Various indices like hydroxyl, carbonyl, vinylidene, lactones, ester, carboxylic acid and crystallinity are calculated and these values increased after a brief induction period. The variation in the mechanical properties like tensile strength and elongation at break percentages are determined. The scanning electron microscopic (SEM) images of weathered PP showed surface cracks when carbonyl index value increases sharply and the mechanical properties show a sudden decrease. Attempted life time prediction using mathematical models showed that the carbonyl growth is more affected by ultraviolet (UV) and cumulative total solar radiation for PP weathered during summer. The loss in tensile strength of PP weathered during summer is more dependent on the average temperature and the UV portion of the total solar radiation whereas, intensity of UV radiation has profound effect on the tensile strength of PP weathered during winter.     

Degradation of 1,4-dioxane using advanced oxidation processes

Introduction  

In the nuclear industry 1,4-dioxane is used as a solvent in liquid scintillation technique for measuring low-energy beta-emitters such as ³H or C¹⁴ in aqueous media. Improper disposal of 1,4-dioxane can contaminate the ground and surface waters. Conventional wastewater treatment processes like chemical treatment, air stripping, carbon adsorption, and biological treatment are ineffective for the degradation of 1,4-dioxane.     

Dissipation behavior of propargite--an acaricide residues in soil, apple (Malus pumila) and tea (Camellia sinensis)

Propargite, recently introduced in India, is an effective acaricide on a large number of crops most of which are consumed by human beings directly or after processing. Therefore, it has become important to check the dissipation behavior of propargite in edible raw commodities, processed products and in the environment. In the present study, dissipation of residue of this acaricide in soil, apple fruit and tea (green tea leaves, manufactured tea, infusion and spent leaves) was studied. Analysis was carried out using high performance-liquid chromatography with UV detection system. The dissipation rate was found to vary with the nature of studied crop/sample. In soil, half-life ranged from 43 to 45 days, while in plant matrices (tea and apple) it ranged 1.66-2.61 days. The percent transfer of propargite residue from manufactured tea to infusion was 23.60-40.00; however, 35.71-53.20% of the residues remained stuck to the spent leaves.     

Bio-efficacy evaluation of nanoformulations of β-cyfluthrin against Callosobruchus maculatus (Coleoptera: Bruchidae)

In the present investigation, bioefficacy of developed β-cyfluthrin formulations, utilizing laboratory synthesized poly(ethylene glycols) based amphiphilic copolymers, were evaluated against Callosobruchus maculatus (Coleoptera: Bruchidae). The bioefficacy data indicated that the formulations developed by utilizing polymers having PEG – 1500 (3c) and PEG – 2000 (3d) as the hydrophilic segment showed greater efficacy after 14 days as evident from EC₅₀ values (2.2 and 1.58 mg L^?1 respectively). Also, release from the commercial SC formulation was faster than developed formulations as the commercial formulation had the lowest EC₅₀ value on the first day (0.51 mg L^?1). The mean EC₅₀ of the commercial formulation against C. maculatus was quite high as compared to those of developed formulations. The results suggest that depending upon the polymer matrix used, the application rate of β-cyfluthrin can be optimized to achieve insect control at the desired level and period. The results described in this paper are promising and provide a comparison of developed formulations with the commercial one showing an earlier degradation of β-cyfluthrin in the latter and relatively prolonged activity in the former.     

Cytogenetic monitoring of men occupationally exposed to airborne pollutants

A study of structural chromosomal aberration frequencies in peripheral blood lymphocytes was performed in a group of 20 professional drivers exposed to airborne pollutants and 20 matching controls. The subjects in the latter group were of the same sex (males) and of similar age as the exposed ones, and also had similar habits of smoking and alcohol. A statistically significant increase of chromosomal aberration was observed in the exposed subjects over the control group. An increasing trend of aberrations was observed with the duration of service (exposure) in the exposed individuals. This study clearly indicates the effect of occupational exposure to airborne pollutants.     

Radical scavenging activity of Trianthema triquetra in male albino rats intoxicated with CCl4

Radical scavenging activity of ethanolic extract of Trianthema triquetra root was investigated against CCl4 in rats. The rats were treated with T. triquetra (100 mg, 200 mg/kg b.w.) for a period of 7 days. Antihepatotoxic effect was studied by assaying the activities of thiobarbituric acid (TBARS), reduced glutathione (GSH), glutathione peroxidase (GPx),catalase (CAT), super oxide dismutase (SOD) and vitamin C (Vit. C). Lipid peroxidation is evidenced by an increase in the value of TBARS and also a distinct diminution in the level of GSH, Vit. C at 200 mg/kg b.w. The activity of antioxidant enzymes, such as GPx, CAT SOD and Vit. E is significantly recovered towards an almost normal level in animals coadministrated with T. triquetra. The maximum protection against CCl4 induced hepatic injury was afforded by the dose of 200 mg/kg b.w. of Trianthema triquetra.     

Groundwater Impacts on Surface Water and Sediment—Gowanus Canal,Brooklyn, New York

The Gowanus Canal Superfund Site in Brooklyn, New York, is an approximately 1.5‐mile (1.61‐km) long estuary that was historically converted into a canal for industrial and commercial purposes. Three manufactured gas plants (MGPs) were formerly located on the Gowanus Canal and discharged waste into it. Surface sediments remain highly contaminated with polycyclic aromatic hydrocarbons (PAHs) long after the MGPs were razed. A hydrogeologic assessment indicates that groundwater passes through the deeper coal tar–contaminated sediment prior to discharging to the canal. This study was undertaken to investigate if groundwater passing through coal tar–contaminated sediment could be responsible for the ongoing contamination of both surface sediments and surface water in the canal. PAH compound distributions in surface water samples collected from the tidal canal at low tide were compared with PAH compounds found in adjacent groundwater‐monitoring wells, point sources (combined sewer overflows [CSOs]), and surface sediments. The results indicate a strong correlation between PAH contaminant distributions in groundwater, sediment, and surface water, indicating that contaminated groundwater passing through the deeper coal tar–contaminated sediments is the primary mechanism contributing to the contamination of both surface sediment and surface water in the canal. Therefore, any sediment remediation efforts in the Gowanus Canal that fail to evaluate and control the upward transport processes have a high chance of failure due to recontamination from below.  ©2016 Wiley Periodicals, Inc.     

Bio-efficacy evaluation of nanoformulations of β-cyfluthrin against Callosobruchus maculatus (Coleoptera: Bruchidae)

In the present investigation, bioefficacy of developed β-cyfluthrin formulations, utilizing laboratory synthesized poly(ethylene glycols) based amphiphilic copolymers, were evaluated against Callosobruchus maculatus (Coleoptera: Bruchidae). The bioefficacy data indicated that the formulations developed by utilizing polymers having PEG - 1500 (3c) and PEG - 2000 (3d) as the hydrophilic segment showed greater efficacy after 14 days as evident from EC(50) values (2.2 and 1.58 mg L(-1) respectively). Also, release from the commercial SC formulation was faster than developed formulations as the commercial formulation had the lowest EC(50) value on the first day (0.51 mg L(-1)). The mean EC(50) of the commercial formulation against C. maculatus was quite high as compared to those of developed formulations. The results suggest that depending upon the polymer matrix used, the application rate of β-cyfluthrin can be optimized to achieve insect control at the desired level and period. The results described in this paper are promising and provide a comparison of developed formulations with the commercial one showing an earlier degradation of β-cyfluthrin in the latter and relatively prolonged activity in the former.