Performance of semipermeable membrane devices for sampling of organic contaminants in groundwater

Lipid-filled semipermeable membrane devices (SPMDs) are receiving increasing attention as passive, in situ samplers for the assessment of environmental pollutant exposure. Although SPMDs have been successfully used in a variety of field studies in surface waters, only a few studies have addressed their characteristics as groundwater samplers. In this study, the performance of the SPMDs for monitoring organic contaminants in groundwater was evaluated in a pilot field application in an area severely contaminated by chemical waste, especially by chlorinated hydrocarbons. The spatial distribution of hydrophobic groundwater contaminants was assessed using a combination of passive sampling with SPMDs and non-target semiquantitative GC-MS analysis. More than 100 contaminants were identified and semiquantitatively determined in SPMD samples. Along the 6 field sites under investigation, a large concentration gradient was observed, which confirms a very limited mobility of hydrophobic substances in dissolved form in the aquifer. The in situ extraction potential of the SPMD is limited by groundwater flow, when the exchange volume of well water during an exposure is lower than the SPMD clearance volume for the analytes. This study demonstrates that SPMDs present a useful tool for sampling and analyzing of groundwater polluted with complex mixtures of hydrophobic chemicals and provides guidance for further development of passive sampling technology for groundwater.     

Effect of organochlorine contaminants and individual biological traits on blubber retinoid concentrations in bottlenose dolphins (Tursiops truncatus)

Here we assessed retinoids as biomarkers of contaminant exposure by studying whether the sex, age, lipid content and organochlorine concentrations of bottlenose dolphins induced variation in retinoid status and its deposition in blubber. Blubber samples were collected from 47 individuals of known age and gender from Sarasota Bay in June 2000 and 2001. The sample included a representative cross-section of the resident dolphin community, with ages ranging from 2 to 50 years. Organochlorine levels showed the age- and sex-related variation commonly observed in other species, with concentrations increasing in youngsters of both sexes and in adult males, and decreasing in adult females after the onset of maturity. Blubber lipid content was low in the overall population and significantly decreased with age in adult males. Retinoid blubber concentrations were comparable to other odontocete species previously studied, and were strongly determined by lipid content. As a consequence of the latter, retinoid concentration was observed to decrease with age in adult males. This effect could not be statistically dissociated from the negative correlation observed between levels of organochlorines and retinoid blubber concentration. Consequently, we could not clarify whether high organochlorine loads in this population lowered retinoid concentrations or, conversely, whether depleted lipid reserves were indeed responsible for the high organochlorine concentrations and the low retinoid levels detected in blubber. With the current knowledge, both options should be considered and investigated, with initial focus on male dolphins.     

Multi-elemental EDXRF mapping of polluted soil from former horticultural land

The distribution of major and trace elements was systematically investigated by use of energy dispersive X-ray fluorescence spectrometry (EDXRF) on a former horticultural soil. The purpose of the study was to combine mapping of soil element concentration levels with multivariate statistics for characterisation of soil metal pollution in relation to previous and present land use. A 1-ha study site was chosen from a former horticulture where a previous preliminary survey indicated increased concentration levels of toxic elements. The soil was sampled from the top 20 cm of the soil surface in a 10 x 10-m grid-like pattern covering the 1-ha study area. In addition, three soil profiles were studied. The elemental composition of the soil samples was investigated by EDXRF while the composition of aqueous soil extracts was determined by total reflection X-ray fluorescence spectrometry (TXRF). Based on mapping and multivariate statistically analysis of the data obtained by EDXRF, most elements were found in almost constant concentration levels in the top soil throughout the investigated site. However, the contents of the toxic elements Zn, Cu, As, and Pb were found to vary significantly within the area. Hence, the samples with high accumulations of As also contained relatively high amounts of Zn, Cu, and Pb, which indicates that toxic-element-containing pesticides have been applied to the soil surface in the area of the former green houses at the study site. The Pb/As mass ratio in the soil indicates that PbHAsO3 was the preferential lead arsenate used for pest management at the investigated site, while Cu as Bordeaux liquid (CuSO4) and Zn were applied to minimize the leaf damaging effect from the former compounds. Calculations indicated that As annually was applied to the soil in the former greenhouses in doses up to 4 kg As/ha while Pb had been annually applied in doses up to 12 kg Pb/ha. The enrichment of Zn, Cu, As and Pb was greatest in the top 20 cm of the soil and no anthropogenic enrichment of these elements occurred below a depth of 50 cm, indicating that the toxic elements are rather immobile in this soil. The results of this investigation suggest that EDXRF used in combination with multivariate statistics is a strong tool for multi-element mapping of elemental contents, sources and mobility in the terrestrial environment.     

Public Participation and Effective Water Governance at the Local Level: A Case Study from a Small Under-Developed Area in Chile

The concept of participation in rural development has been evolutionary for the past two decades with those involved, such as development agencies and governments, particularly in rural water supply, re-evaluating their active role. The move towards effective community participation has encouraged a shift from the traditional top-down to a bottom-up approach whereby there is a decentralisation of unevenly distributed resources and power to empower a community and allow mobility of ‘people participation’. The Molinos water project is the first large-scale development project of its kind introduced into the village of Molinos in an under-developed area of Chile, where there has been no tradition of people participation. The project objective was to implement a low technology, low budget water treatment plant to the village of Molinos. Various aspects have hindered the continued development of the project including both technical and financial. In terms of people participation, the initial approach used was the top-down approach. There was a failure to fully integrate the community or inform the community in a formal manner about the project and consult them regarding key project issues. This case study illustrates that the lack of comprehensive consultation and the low level of participation of the community on the participatory scale does not achieve much in terms of people-centred benefits. For governance at the local level to be effective, participation should be inclusive and communicative so as to enhance transparency throughout the project lifetime. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Economic Underdevelopment And Sustainable Development In The World:Conditioning Factors,Problems And Opportunities

This paper deals with the various factors that condition underdevelopment in the world. It suggests some alternatives and points out the potential opportunities that both the developed and the underdeveloped world will have in the coming years to change the gloomy prospects that we see today. The present paper outlines the trends in historical priorities in development, changing as they pass from economic development to social development to ecological conservation – the three pillars of Sustainable Development.The paper analyses the importance of geography, a very relevant and often neglected conditioning factor. Also, it analyses the role of socio-economic conditioning factors like political immaturity, demographics, land ownership and external debt.Furthermore, the current opportunities for economic take-off are presented, from cash surpluses to low interest rates, from natural resource management to tourism or migration, from the Information Revolution to liberalisation of agricultural markets. Current obstacles are also analysed. The paper, on the basis of current facts and figures, reaches the conclusion that there is a structural need for sustained development aid for most poor countries, but it must be distributed in a more rational way.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

“Measuring Sustainability”: A Multi-Criterion Framework

So far, the elementary question of whether one country’s or region’s economy is moving towards sustainability or away from it cannot be answered with unanimous consensus on the ‘measuring rod(s)’ to be employed. The main assumption of this article is that sustainability assessment needs a set of multi-dimensional indicators. From this assumption a question arises: how could such indicators be aggregated? Often, some indicators improve while others deteriorate. For instance, when incomes grow, SO₂ might go down while CO₂ increases. It has to be noted that this is the classical conflictual situation studied in multi-criteria decision theory. The use of a multi-criterion framework for making operational the ‘measuring of sustainability’ is discussed here by means of illustrative examples and more formal arguments.     

An Assessment of the Valuation Methods Used to Calculate the Index of Sustainable Economic Welfare (ISEW), Genuine Progress Indicator (GPI), and Sustainable Net Benefit Index (SNBI)

For some time now, ecological economists have been putting forward a ‘threshold hypothesis’ – the notion that when macroeconomic systems expand beyond a certain size, the additional cost of growth exceeds the flow of additional benefits. In order to support their belief, ecological economists have developed a number of similar indexes to measure and compare the benefits and costs of growth (e.g., the Index of Sustainable Economic Welfare and the Genuine Progress Indicator). In virtually every instance where an index of this type has been calculated for a particular country, the movement of the index appears to reinforce the existence of the threshold hypothesis. Of late, a number of observers have expressed concerns about whether these alternative indexes reflect concrete reality or the prejudices of ecological economists. In view of these concerns, this paper closely examines the valuation methods used in the calculation the Index of Sustainable Economic Welfare, the Genuine Progress Indicator, and the Sustainable Net Benefit Index. It is argued that a consistent and more robust set of valuation techniques is required in order for these alternative indexes to gain broad acceptability.*Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Perceived Impacts of Ecotourism on Environmental Learning and Conservation: Turtle Watching as a Case Study

Using a case study, involving turtle-based ecotourism, we explore the role of ecotourism in promoting environmental learning and in sustaining conservation of nature. Mon Repos Conservation Park (an important marine turtle rookery involved in ecotourism) in Queensland, Australia, was selected for this study and visitors were surveyed using a structured questionnaire. The reported on-site experiences of respondents are analysed to identify important factors that alter their stated conservation attitudes and behaviours. The impact of these factors (such as the amount of environmental education that respondents claimed they obtained, sighting of sea turtles, nationality) is quantified using regression analyses. There has been little previous quantification of such influences. The study reveals that a considerable amount of environmental knowledge is gained by visitors to Mon Repos. The ecotourism experience, involving environmental education and seeing of turtles, was found to have positive and statistically significant impacts on the visitors' stated desire and intended behaviour to protect sea turtles. The study reveals the importance of learning and the interaction of tourists with wildlife as a contributor to their pro-conservation sentiments and actions. It shows how ecotourism can support nature conservation. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Preliminary Studies on Converting Agricultural Waste into Biodegradable Plastics—Part IV: Polysaccharide Containing Natural Materials

Corn distillers’ dry grain, corncob powder, hardwood powder, and sugar beet pulp were separately anionized by oxidation with sodium hypochlorite in aqueous solution. Solid reaction products instantly precipitated upon admixing each of the above-oxidized materials with soy protein isolate. Infrared spectra and differential scanning calorimetry supported the hypothesis that soy protein isolate complexed with all of the above-oxidized polysaccharides. Reaction products with either oxidized corn distillers’ dry grain or oxidized sugar beet pulp provided hard, brittle pellets with tensile strengths as high as 9.5 MPa, suggesting that these materials could be viable as biodegradable plastics.     

Novel Biocomposites Sheet Molding Compounds for Low Cost Housing Panel Applications

Biocomposites were made by a novel high volume processing technique named biocomposite sheet molding compound panel (BCSMCP) manufacturing process. This process design was inspired by the commercial glass fiber–polyester resin composite fabrication method called sheet molding compounding (SMC). This process yields continuous production of biocomposites on a large scale, and thus can be easily adopted in industries. A unique fiber dispersion method, which enabled uniform distribution of natural fibers, was used in this process. Consistency of the process was tested by evaluating the repeatability of the resultant materials mechanical properties. The low cost biocomposites produced as a result of the processing will be used for various panel applications such as housing and transportation. The molded samples were tested for various mechanical and thermal properties, in accordance with ASTM procedures. The biocomposites were made with various natural fibers including, big blue stem grass, jute, and industrial hemp. By combining different natural fibers in varying mass fractions, hybrid biocomposites were made using this process. Grass fiber reinforced polyester biocomposites processed by the SMC line showed very promising results.