An overview and analysis of site remediation technologies

This paper presents an analysis of the site restoration techniques that may be employed in a variety of contaminated site cleanup programs. It is recognized that no single specific technology may be considered as a panacea for all contaminated site problems. An easy-to-use summary of the analysis of the important parameters that will help in the selection and implementation of one or more appropriate technologies in a defined set of site and contaminant characteristics is also included.     

Zonal management of arsenic contaminated ground water in Northwestern Bangladesh

This paper used ordinary kriging to spatially map arsenic contamination in shallow aquifers of Northwestern Bangladesh (total area  35,000 km²). The Northwestern region was selected because it represents a relatively safer source of large-scale and affordable water supply for the rest of Bangladesh currently faced with extensive arsenic contamination in drinking water (such as the Southern regions). Hence, the work appropriately explored sustainability issues by building upon a previously published study (Hossain et al., 2007; Water Resources Management, vol. 21: 1245–1261) where a more general nation-wide assessment afforded by kriging was identified. The arsenic database for reference comprised the nation-wide survey (of 3534 drinking wells) completed in 1999 by the British Geological Survey (BGS) in collaboration with the Department of Public Health Engineering (DPHE) of Bangladesh. Randomly sampled networks of zones from this reference database were used to develop an empirical variogram and develop maps of zonal arsenic concentration for the Northwestern region. The remaining non-sampled zones from the reference database were used to assess the accuracy of the kriged maps. Two additional criteria were explored: (1) the ability of geostatistical interpolators such as kriging to extrapolate information on spatial structure of arsenic contamination beyond small-scale exploratory domains; (2) the impact of a priori knowledge of anisotropic variability on the effectiveness of geostatistically based management. On the average, the kriging method was found to have a 90% probability of successful prediction of safe zones according to the WHO safe limit of 10 ppb while for the Bangladesh safe limit of 50 ppb, the safe zone prediction probability was 97%. Compared to the previous study by Hossain et al. (2007) over the rest of the contaminated country side, the probability of successful detection of safe zones in the Northwest is observed to be about 25% higher. An a priori knowledge of anisotropy was found to have inconclusive impact on the effectiveness of kriging. It was, however, hypothesized that a preferential sampling strategy that honored anisotropy could be necessary to reach a more definitive conclusion in regards to this issue.     

Attenuation of Gaseous Pollutants by Greenbelts

The article draws attention towards the importance ofgreenbelts in attenuating gaseous pollutants andpresents the meteorological, physico-chemical,biological, and horticultural dimensions associatedwith effective greenbelt design.We have presented the gist of a system ofmethodologies, developed by us, for greenbelt design. A case study demonstrating the applicability of thesystem has been presented.     

A spatial econometric analysis of convergence in global environmental performance

Environmental Science and Pollution Research - This study intends to test the presence of β-convergence in the global Environmental Performance (EP). For this purpose, spatial Green Solow...     

Ag nanoparticle-decorated chitosan/SrSnO3 nanocomposite for ultrafast elimination of antibiotic linezolid and methylene blue

Environmental Science and Pollution Research - Effective design of ultrafast new-generation photocatalysts is a challenging task that requires highly dedicated efforts. This research focused on the...     

Economic effects of riverbank erosion: some evidence from bangladesh

In this paper I investigate some of the economic effects of riverbank erosion in Bangladesh. The study was conducted in one village over the period 1979–89. Between these dates the village lost almost 20 per cent of its farmland to riverbank erosion. This resulted in a loss of more than 50 per cent of crop income (at 1989 prices). About 45 per cent of households were affected during the period. It appears, however, that there is little understanding among the relevant government agencies and non-governmental organisations of the severity of riverbank erosion in Bangladesh. This article aims to provide, therefore, some basic information on the various economic effects of this natural hazard.     

I2SI: A comprehensive quantitative tool for inherent safety and cost evaluation

This paper presents details of an integrated inherent safety index (I2SI). The conceptual framework of this index was presented at the 37th Annual Loss Prevention Symposium of the AIChE (2003) and published in Process Safety Progress (volume 23(2), 136–148, 2004). In addition to the framework, the current paper discusses additional features of the index such as the cost model and system design model, which were not presented or discussed earlier. I2SI is called an integrated index because the procedure considers the life cycle of the process with economic evaluation and hazard potential identification for each option. I2SI is comprised of sub-indices which account for hazard potential, inherent safety potential, and add-on control requirements. In addition to evaluating these respective characteristics, there are also indices that measure the economic potential of the option. To demonstrate the applicability and efficacy of I2SI, an application of the index to three acrylic acid production options is also discussed in the paper.     

A criterion for developing credible accident scenarios for risk assessment

Maximum credible accident analysis is one of the most widely used concepts in risk assessment of chemical process industries. Central to this concept is the aspect of ‘credibility’ of envisaged accident scenarios. However, thus far the term credibility is mostly treated qualitatively, based on the subjective judgement of the concerned analysts. This causes wide variation in the results of the studies conducted on the same industrial unit by different analysts.

This paper presents an attempt to develop a criterion using which credible accident scenarios may be identified from among a large number of possibilities. The credible scenarios thus identified may then be processed for detailed consequence analysis. This would help in reducing the cost of the analysis and prevent undue emphasis on less credible scenarios at the expense of more credible ones.     

River Dolphins in Bangladesh: Conservation and the Effects of Water Development

Platanista gangetica ) are threatened in Bangladesh from the effects of dams, large embankment schemes, dredging, fisheries bycatch, directed hunting, and water pollution. Visual surveys of the section of the Jamuna River located between the divergence of the Old Brahmaputra River and the confluence of the Padma River and the section of the Kushiyara River located between the Bangladesh–India border and the confluence of the Korangi River recorded a sighting rate of 0.13 sightings/km (mean group size = 1.8 dolphins) and 0.08 sightings/km (mean group size = 3.8 dolphins), respectively. These sections of river were considered to be priority areas for investigation because several water development projects have already been constructed and more are planned for the areas. During the surveys we examined the remains of dolphins caught accidentally in plastic gillnets and observed fishermen catching the fish species Clupisoma garua using dolphin oil and body parts as a fish attractor. Additional studies are needed to assess the status of dolphins and effects of water development and fisheries bycatch. Feasibility studies should be conducted on designating dolphin/fish sanctuaries and creating artificial habitat or enhancing existing habitat in eddy countercurrent scour pools to mitigate deleterious impacts. The environmental requirements of river dolphins reflect the needs of productive and biotically diverse tropical rivers.