Willingness to pay towards a public good: how does a refund option affect stated values?

Mandatory taxes and/or voluntary contributions are commonly adopted as the payment vehicle when eliciting willingness to pay (WTP) in environmental valuation studies. While mandatory taxes may arouse negative feelings, voluntary contributions may lead to strategic behaviour (over bidding) or free riding (under bidding). In this paper, we explore an alternative payment vehicle which avoids the draconian undertones associated with taxes and may be more incentive compatible than a voluntary contribution – a tax that incorporates a refund option. The template for such a payment vehicle is the value added tax charged to tourists in Ireland, but which can be reclaimed on exiting the country. In the context of raising public funds to support the conservation of rural countryside landscape, a comparison is made between the elicited WTP via a mandatory tax and that elicited via the alternative payment method incorporating a refund option. While we observe similar participation rates between the two payment methods, the refund option reveals a higher stated WTP.     

A review on recent progress in observations,sources, classification and regulations of PM<Subscript>2.5</Subscript> in Asian environments

Natural and human activities generate a significant amount of PM_2.5 (particles ≤2.5 μm in aerodynamic diameter) into the surrounding atmospheric environments. Because of their small size, they can remain suspended for a relatively longer time in the air than coarse particles and thus can travel long distances in the atmosphere. PM_2.5 is one of the key indicators of pollution and known to cause numerous types of respiratory and lung-related diseases. Due to poor implementation of regulations and a time lag in introducing the vehicle technology, levels of PM_2.5 in most Asian cities are much worse than those in European environments. Dedicated reviews on understanding the characteristics of PM_2.5 in Asian urban environments are currently missing but much needed. In order to fill the existing gaps in the literature, the aim of this review article is to describe dominating sources and their classification, followed by current status and health impact of PM_2.5, in Asian countries. Further objectives include a critical synthesis of the topics such as secondary and tertiary aerosol formation, chemical composition, monitoring and modelling methods, source apportionment, emissions and exposure impacts. The review concludes with the synthesis of regulatory guidelines and future perspectives for PM_2.5 in Asian countries. A critical synthesis of literature suggests a lack of exposure and monitoring studies to inform personal exposure in the household and rural areas of Asian environments.     

Appraisal of salinity and fluoride in a semi-arid region of India using statistical and multivariate techniques

Various physico-chemical parameters, including fluoride (F⁻), were analyzed to understand the hydro-geochemistry of an aquifer in a semi-arid region of India. Furthermore, the quality of the shallow and deep aquifer (using tube well and hand pumps) was also investigated for their best ecological use including drinking, domestic, agricultural and other activities. Different multivariate techniques were applied to understand the groundwater chemistry of the aquifer. Findings of the correlation matrix were strengthened by the factor analysis, and this shows that salinity is mainly caused by magnesium salts as compared to calcium salts in the aquifer. The problem of salinization seems mainly compounded by the contamination of the shallow aquifers by the recharging water. High factor loading of total alkalinity and bicarbonates indicates that total alkalinity was mainly due to carbonates and bicarbonates of sodium. The concentration of F⁻ was found more in the deep aquifer than the shallow aquifer. Further, only a few groundwater samples lie below the permissible limit of F⁻, and this indicates a risk of dental caries in the populace of the study area. The present study indicates that regular monitoring of groundwater is an important step to avoid human health risks and to assess its quality for various ecological purposes.     

Experimental investigation of solar still with opaque north triangular face

Developing a compact, simple, and productive solar still is a main challenge. This paper describes a simple modification of the solar still that significantly enhances its productivity. A laboratory scale of modified single effect double slope glass solar still with the opaque triangular north wall has been developed and tested for enhancement of productivity in sunny days of the summer season in the month of April. The experiments on still have been carried out under three levels of water depths from 1 to 3 cm and compared it with the performance of conventional still of double slope single effect solar still of the same size. It is clear from the observations that opaque type still gave maximum distillate of 1793 ml at 1 cm depth of water while conventional still could produce only 1519 ml for the same depth of water. Also, for 2 and 3 cm depth of water, the opaque type still found to be more productive than conventional double slope solar still. As the former produced 1532 and 1464 ml while the latter produced 1328 and 1235 ml, for 2 and 3 cm depth of water, respectively.     

Artificially roughened solar air heater: A comparative study

Artificially roughened solar air heater has been topic in research for the last 30 years. Prediction of heat transfer and fluid flow processes of an artificially roughened solar air heater can be obtained by three approaches: theoretical, experimental, and computational fluid dynamics (CFD). This article provides a comprehensive review of the published literature on the investigations of artificially roughened solar air heater. In the present article, an attempt has been made to present holistic view of various roughness geometries used for creating artificial roughness in solar air heater for heat transfer enhancement. This extensive review reveals that quite a lot of work has been reported on design of artificially roughened solar air heater by experimental approach but only a few studies have been done by theoretical and CFD approaches. Finally this article presents a comparative study of thermo-hydraulic performance of 21 different types of artificial roughness geometries attached on the absorber plate of solar air heater in terms of thermo-hydraulic performance parameter. Heat transfer and friction factor correlations developed by various investigators for different types of artificially roughened solar air heaters have also been reported in this article.     

Syntrophic co-culture of Bacillus subtilis and Klebsiella pneumonia for degradation of kraft lignin discharged from rayon grade pulp industry

In order to search the degradability of kraft lignin, the potential bacterial strains Bacillus subtilis (GU193980) and Klebsiella pneumoniae (GU193981) were isolated, screened and applied in axenic and co-culture conditions. Results revealed that mixed culture showed better decolorization efficiency (80%) and reduction of pollution parameters (COD 73% and BOD 62%) than axenic culture. This indicated syntrophic growth of these two bacteria rather than any antagonistic effect. The HPLC analysis of degraded samples of kraft lignin has shown the reduction in peak area compared to control, suggesting that decrease in color intensity might be largely attributed to the degradation of lignin by isolated bacteria. Further, the GC–MS analysis showed that most of the compounds detected in control were diminished after bacterial treatment. Further, the seed germination test using Phaseolus aureus has supported the detoxification of bacterial decolorized kraft lignin for environmental safety. All these observations have revealed that the developed bacterial co-culture was capable for the effective degradation and decolorization of lignin containing rayon grade pulp mill wastewater for environmental safety.     

Physiological changes and molluscicidal effects of crude latex and Milin on Biomphalaria glabrata

Euphorbian latex is commonly used as molluscicides and the Euphorbia milii latex was reported as most powerful molluscicidal agents. The physiological and lethal effects of the latex components of Euphorbia milii, on the intermediate host Biomphalaria spp., of the human liver parasite Schistosoma mansoni were described in this study. The standard methodologies for testing plant derived molluscicides formulated by World Health Organisation (WHO) were followed with some modifications. The young specimen of fresh water snails showed altered physiological and physical response towards latex components. The working concentration of non-proteinaceous fraction (up to 0.1%) of the latex reduced the active physiological behaviour but was non-lethal to young specimen of snails. However, proteinaceous fractions (0.1mg/l) of the latex were found lethal to snail population, and lethality was enhanced with small amount of the non-proteinaceous fraction (0.01%) of the latex. Milin, a serine protease(up to 0.1mg/l), isolated from the latex of Euphorbia milii significantly reduced the growth and feeding activity but was not lethal to young specimen of snails. With an addition of 0.01% of non-proteinaceous fractions to Milin, lethality result was similar to that of crude latex. Milin is likely to be responsible for alteration of normal physiological functions and lethality of snails, thus it may be used as a molluscicide to control transmission of the endemic disease schistosomiasis.     

Effect of stocking density and food quality on the growth and fecundity of an epigeic earthworm (<Emphasis Type="Italic">Eisenia fetida</Emphasis>) during vermicomposting

Physico-chemical characteristics of the feed and optimum worm density are important parameters for the efficient working of a vermicomposting system. Overcrowding of worms can affect the efficiency of a vermicomposting system even if all other parameters have been optimized. This article reports the effect of stocking density and feed quality on the growth and fecundity of Eisenia fetida under laboratory conditions. The feed mixtures contained cow dung and textile mill wastewater sludge in different ratios. Three feed mixtures and five stocking rates (1, 2, 4, 8, and 12) were tested for 12 weeks. The results showed that E. fetida growth rate was faster at higher stocking densities; however, biomass gain per worm was faster at lower stocking densities. Sexual maturity was attained earlier at higher stocking densities. Growth rate was highest in 100% cow dung at all the stocking densities when compared to textile mill wastewater sludge containing feed mixtures. A worm population of 27–53 worms per kg of feed was found to be the most favorable stocking density.     

Status and Environmental Impact of Emissions from Thermal Power Plants in India

The main emissions from coal combustion at thermal power plants are carbon dioxide (CO₂), nitrogen oxides, sulfur oxides, chlorofluorocarbons (CFCs), and airborne inorganic particles such as fly ash and soot; CO₂, methane, and CFCs are greenhouse gases. These emissions are considered to be partially responsible for harmful global climate change. This review summarizes the status of thermal power plants in India and their various types of emissions that directly or indirectly produce harmful effects on the environment and human health. Moreover, it focuses on various types of preventive measures used to avoid/minimize emissions.