Sustainability and sustainable development: Historical and conceptual review

The vagueness of the concept of sustainable development, coupled with its increasing importance in national, international and corporate policies, has led to a large political battle for influence over our future by linking interpretation to the concept. This has resulted in a wide variety of definitions and interpretations that are skewed towards institutional and group prerogatives rather than compounding the essence of the concept, which has been inherent in traditional beliefs and practices. A systematic analysis of representative definitions and interpretations presented in this article reveals that most of the contemporary definitions focus on specific elements while failing to capture the whole spectrum. Such a historical and conceptual analysis focusing on the analysis of the metaphorical and epistemological basis of the different definitions is believed to be the first step towards developing a concrete body of theory on sustainability and sustainable development.     

Household-level preferences for mitigation of Prosopis juliflora invasion in the Afar region of Ethiopia: a contingent valuation

Prosopis juliflora, which is an alien tree species in Ethiopia, has invaded over 360,500 ha of land in the Afar region of the country and is threatening pastoral livelihoods. We conducted a contingent valuation study to assess rural households’ willingness to contribute in cash and labor to mitigate P. juliflora invasion in three districts of Afar. Results show that about 84% of the respondents prefer an intervention involving complete eradication of P. juliflora. The lower and upper bound median willingness to contribute to this intervention were 9.97 and 13.42 USD/household/year in cash and 30 and 43 days/household/year in labor. Off-farm income and P. juliflora invasion levels on pasturelands are among the factors affecting willingness to contribute to the mitigation of P. juliflora invasion. Incentives to local people and having a proper institutional setup that involves local culture and institutions are important for mobilizing people on a voluntary basis for mitigation of P. juliflora invasion.     

Behavioural and biochemical responses of two marine invertebrates Scrobicularia plana and Hediste diversicolor to copper oxide nanoparticles

Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10 μg L⁻¹) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO₃. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves.     

Fluoride content of Ethiopian khat (Catha edulis Forsk) chewing leaves

The levels of water soluble and total fluoride concentration in 11 different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by fluoride ion-selective electrode. Known amounts of fresh khat samples were suspended in deionized water, stirred, and the supernatants exposed to a chelator that decomplexes fluoride were assayed. The total fluoride concentration in the leaves was also analyzed after the leaves were dried, charred, and ashed. Water soluble and total fluoride concentration in khat varieties varied, ranging from 0.19 to 0.43 µg g^?1 fresh weight and 3.4 to 7.1 µg g^?1 dry weight, respectively. The fluoride concentration in matured leaves (12 µg g^?1) was higher than that in young leaves (6.5 µg g^?1) dry weight. Assuming that daily khat leaves chewing for an adult is 100 g, fluoride intake from chewing leaves of the analyzed khat varieties is far below the daily fluoride tolerable upper limit. The safe intake of fluoride is recommended to be 1.5–4.0 mg day^?1 for adults and less for children. However, chewing khat leaves may contribute a significant amount of fluoride for the total daily intake of an individual and should not be overlooked while estimating the total dietary intake of fluoride for individuals chewing khat leaves regularly.     

Impact of drought‐related vaccination on livestock mortality in pastoralist areas of Ethiopia

Under a national Livestock Policy Forum in Ethiopia the impact of livestock vaccination during drought was assessed in order to inform the development of a best‐practice guideline. For each of the different types of vaccine used during drought years there was no significant difference in livestock mortality, for any species, in vaccinated compared with non‐vaccinated herds. The limited impact of vaccination on livestock mortality was attributed to weaknesses in the design and implementation of vaccination programmes, including use of inappropriate vaccines, low vaccination coverage, problems with vaccine dosing, incorrect timing of vaccination and problems with vaccine storage. If these weaknesses could be overcome vaccination could be a useful means to protect livestock assets, with considerable benefit‐cost ratios. Vaccination should be conducted as a standard preventive measure during normal years, and programme design should be informed by participatory epidemiological studies.     

Correlates of women’s environmental behaviors: a study in Pawe Woreda,Northwest Ethiopia

Available cross-country, macro-level evidence regarding gender differences in environmental behaviors shows women are more environmentally concerned and responsive than men. However, while such macro-level evidence helps understand patterns of women’s environmental behaviors at a much broader level, it does not allow deeper insights into particular patterns at a single location or in much smaller areas. Tailor-made interventions needed to address livelihood and environmental strategies of poor rural women become meaningful if studies aim at revealing context specific, local variations in women’s environmental behaviors. In this context, there is only little research for Ethiopia regarding what influences women’s response to environmental problems. The objective of this research was to describe women’s response to environmental problems in Pawe Woreda and examine the demographic, socioeconomic, and institutional correlates of this response, with particular emphasis to forest resources. Data were primarily obtained from a sample of 363 households in a multi-stage sample survey and were analyzed mainly using a multivariate logistic regression model. We found that all except one of the demographic and socioeconomic variables included in the model were found to be statistically significant correlates of woman’s environmental response, but the institutional variable was not significantly associated with a woman’s environmental response. However, the qualitative result for additional institutional issues revealed the importance of land tenure. Many of the results are in line with the existing literature.     

Fate and effects of metal-based nanoparticles in two marine invertebrates,the bivalve mollusc Scrobicularia plana and the annelid polychaete Hediste diversicolor

The objective of this paper is to synthesize results from seven published research papers employing different experimental approaches to evaluate the fate of metal-based nanoparticles (Ag NPs, Au NPs, CuO NPs, CdS NPs, ZnO NPs) in the marine environment and their effects on two marine endobenthic species, the bivalve Scrobicularia plana and the ragworm Hediste diversicolor. The experiments were carried out under laboratory (microcosms) conditions or under environmentally realistic conditions in outdoor mesocosms. Based on results from these seven papers, we addressed the following research questions: (1) How did the environment into which nanoparticles were released affect their physicochemical properties?, (2) How did the route of exposure (seawater, food, sediment) influence bioaccumulation and effects?, (3) Which biomarkers were the most responsive? and (4) Which tools were the most efficient to evaluate the fate and effects of NPs in the marine environment? The obtained results showed that metal‐based NPs in general were highly agglomerated/aggregated in seawater. DGT tools could be used to estimate the bioavailability of metals released from NPs under soluble form in the aquatic environment. Both metal forms (nanoparticulate, soluble) were generally bioaccumulated in both species. Among biochemical tools, GST and CAT were the most sensitive revealing the enhancement of anti-oxidant defenses in both species exposed to sub-lethal concentrations of metal-based NPs. Apoptosis and genotoxicity were frequently observed.     

Highway runoff quality in Ireland

Highway runoff has been identified as a significant source of contaminants that impact on the receiving aquatic environment. Several studies have been completed documenting the characteristics of highway runoff and its implication to the receiving water in the UK and elsewhere. However, very little information is available for Ireland. The objective of this study was to determine the quality of highway runoff from major Irish roads under the current road drainage design and maintenance practice. Four sites were selected from the M4 and the M7 motorways outside Dublin. Automatic samplers and continuous monitoring devices were deployed to sample and monitor the runoff quality and quantity. More than 42 storm events were sampled and analysed for the heavy metals Cd, Cu, Pb, and Zn, 16 US EPA specified PAHs, volatile organic compounds including MTBE, and a number of conventional pollutants. All samples were analysed based on the Standard Methods. Significant quantities of solids and heavy metals were detected at all sites. PAHs were not detected very often, but when detected the values were different from quantities observed in UK highways. The heavy metal concentrations were strongly related to the total suspended solids concentrations, which has a useful implication for runoff management strategies. No strong relationship was discovered between pollutant concentrations and event characteristics such as rainfall intensity, antecedent dry days (ADD), or rainfall depth (volume). This study has demonstrated that runoff from Irish motorways was not any cleaner than in the UK although the traffic volume at the monitored sites was relatively smaller. This calls for a site specific investigation of highway runoff quality before adopting a given management strategy.     

The greenhouse work environment: a modifier of occupational pesticide exposure?

Abstract

Greenhouses are enclosed structures which have various characteristics that enhance crop productivity, but the implications for workers’ pesticide exposure and uptake are not well understood. A narrative literature review was conducted to explore the mechanism/s of interactions between greenhouse characteristics and occupational pesticide exposure. Using a “work”, “worker” and “workplace” conceptual framework, the greenhouse environment (hot and humid microclimate, limited space and dense crop arrangements) combines with work characteristics (high work and pesticide use intensity, multi-tasking, predominantly manual spraying techniques and quick reentry to treated farms) to potentially increase occupational pesticide exposure, compared with open field farming. Greenhouse environments, are variable but have been shown to influence pesticide availability, route, pathways and frequency of exposure, deposition and distribution on a worker’s body as well as use and performance of exposure control methods. Training programs can emphasize the differences in exposure potential between greenhouse and open field farming. Development of tailored guidelines for exposure control strategies to better suit the level of uniqueness of greenhouse agriculture seems warranted.