Explaining the Performance of Mature Municipal Solid Waste Recycling Programs

This paper assesses the contextual, programmatic and decision-making factors that affect the performance of mature municipal solid waste recycling programs. Tobit models were prepared for cities with populations of less than or more than 25?000 to facilitate analysis of recycling performance. Recycling participation rates were found to be higher among cities in both groups that offered more convenient recycling programs and whose residents had a higher mean household income. The larger cities that achieved higher participation rates employed a decision-making process known as ‘collaborative learning’, imposed sanctions on improper sorting recyclable materials, and had a larger non-minority population. Among smaller cities, higher participation was attained by using variable fee pricing for solid waste collection and by mandating household participation. The study findings suggest that future research should focus on improved ways to characterize and measure the decision-making processes used to make policy changes in order to facilitate analysis of the causal and temporal relationships between decision-making processes and program performance.     

Complex genetic structure of a euryhaline marine fish in temporarily open/closed estuaries from the wider Gulf of Aden

Temporarily open/closed estuaries (TOCEs) are major ecosystems of the Indian Ocean coastal zones. Their functioning is tightly linked to climatic events such as monsoons and storms, and their mouth can close up for prolonged and variable periods of time, thus limiting their connectivity with the marine environment. Two types of genetic markers (i.e., mitochondrial cytochrome c oxidase I (COI) gene and microsatellites) were used to assess the genetic structure of 288 individuals of Terapon jarbua, a widely distributed fish species in the wider Gulf of Aden. Firstly, the hypothesis of panmixia was tested. Then, alternative hypotheses were investigated to explain the population genetic structure of T. jarbua: could it be shaped by (1) regional biogeographic barriers (i.e., Socotra Island vs. mainland Yemen) and/or (2) the particular functioning of TOCEs in relation to the species life cycle and particular physical ocean parameters? On one hand, the polymorphism of the COI inferred (1) a high haplotype diversity and a reduced nucleotide diversity over the whole data set and (2) a “star-like” shape of the haplotype network, thus suggesting a population expansion after local extinctions during the Pleistocene glaciations. On a second hand, the genotyping of eight microsatellites showed a significant genetic differentiation between T. jarbua populations in the wider Gulf of Aden (F _ST = 0.035, p < 0.01), and thus, the panmixia hypothesis was rejected. Analyses of molecular variance results did not show any significant structure between Socotra Island and mainland Yemen and thus did not support the role of biogeographic barriers in structuring T. jarbua populations. Significant multi-locus deficits in heterozygotes at particular locations displaying high levels of F _IS were recorded. It was suggested that a possible Wahlund effect took place in those TOCEs which could gather several cohorts of larvae stemming from different marine subpopulations over the sampled area. The present study emphasized the uniqueness of each TOCE as a potential reservoir of biodiversity and the urgent need for a better conservation program of those estuaries in the region, in order to avoid habitat fragmentation and permanent closure of those nursery areas by human activities.     

Resource conservation in the pulp and paper industries—rational-use-of-energy approach

Sharp rises in energy prices have generated an interest in the pulp and paper industries in cogeneration and heat pump applications. However, the institutional and industry-specific barriers to their implementation, despite economic viability, indicate the inadequacies of the energy conservation and energy saving approaches to minimise energy costs. A systems approach, referred to as rational-use-of-energy, is proposed to overcome some of the barriers and to highlight the conservation potential of other resources, such as chemicals and water at appreciably low effluent loads.     

Environmental education — Implications for public policy

Summary This paper examines first the practical requirements of educational participation, and attempts to define the kind of education system (both structure and curriculum) which would meet these requirements. Next, it describes the special role of environmental education for all age groups, not just those of school age. Organizational and curriculum models are presented to illustrate how locally based education could be developed in such a way as to draw together teachers, local people and technical professionals working in the locality, to make a collective learning process. Finally some conclusions are drawn about the politics of environmental education.Miss Jean Forbes is a Senior Lecturer in the Department of Town and Regional Planning at the University of Glasgow.     

Uptake and transformation of phenol and chlorophenols by hairy root cultures of Daucus carota, Ipomoea batatas and Solanum aviculare

Hairy root cultures of Daucus carota L., Ipomoea batatas L. and Solanum aviculare Forst were investigated for their susceptibility to the highly toxic pollutants phenol and chlorophenols and for the involvement of inherent peroxidases in the removal of phenols from liquid media. Roots of D. carota grew normally in medium containing 1000 micromol l(-1) of phenol, whilst normal growth of roots of I. batatas and S. aviculare was only possible at levels up to 500 micromol l(-1). In the presence of chlorophenols, normal root growth was possible only in concentrations not exceeding 50 micromol l(-1), except for I. batatas which was severely affected at all concentrations. Despite the reduction in biomass, the growth of S. aviculare cultures was sustained in medium containing up to 2000 micromol l(-1) of phenol or 2-chlorophenol, and up to 500 micromol l(-1) of 2,6-dichlorophenol. The amounts of phenol removed by the roots within 72 h of treatment were 72.7%, 90.7% and 98.6% of the initial concentration for D. carota, I. batatas and S. aviculare, respectively. For the removal of 2,6-dichlorophenol the values were, respectively, 83.0%, 57.7% and 73.1%. Phenols labelled with 14C were absorbed by the root tissues and condensed with highly polar cellular substances as well as being incorporated into the cell walls or membranes. The results suggest that S. aviculare, an ornamental plant, would be best suited for remediation trials under field conditions.     

Polybrominated diphenyl ethers in fish and wastewater samples from an area of the Penobscot River in central Maine

Polybrominated diphenyl ethers (PBDEs) are one class of flame retardants commonly used in textiles, foams and plastics. They are similar in behavior to the well-studied polychlorinated biphenyls and growing evidence suggests they are widespread global environmental pollutants that are capable of bioaccumulation. Fish tissue samples were collected from sites along the Penobscot River in central Maine. The total concentration of tetra- to hepta-PBDEs in these samples were calculated and generally increased from upstream to downstream locations ranging from 800 to 1810 ng/g lipid at the northernmost site to 5750-29000 ng/g at the downstream sampling site. BDE-47, 99 and 100 were the predominant congeners found in the fish tissue. Wastewater treatment plants (WWTPs) are one of the potential sources of these compounds to the environment through effluent discharge and landspreading of biosolids. Influent, effluent, activated sludge and dewatered biosolids were collected and analyzed for PBDE congeners from a WWTP at Orono, Maine. PBDE congeners were detectable in effluent samples at concentrations from 0.31 to 0.90 microg/l, in the activated sludge at 1.32-3.8 microg/l and in the influent at 4.2-4.3 microg/l, but the majority of the material was concentrated in the biosolids. Total concentration in the biosolids was 2320-3530 microg/kg dry weight.     

Driver’s mental workload prediction model based on physiological indices

Developing an early warning model to predict the driver’s mental workload (MWL) is critical and helpful, especially for new or less experienced drivers. The present study aims to investigate the correlation between new drivers’ MWL and their work performance, regarding the number of errors. Additionally, the group method of data handling is used to establish the driver’s MWL predictive model based on subjective rating (NASA task load index [NASA-TLX]) and six physiological indices. The results indicate that the NASA-TLX and the number of errors are positively correlated, and the predictive model shows the validity of the proposed model with an R² value of 0.745. The proposed model is expected to provide a reference value for the new drivers of their MWL by providing the physiological indices, and the driving lesson plans can be proposed to sustain an appropriate MWL as well as improve the driver’s work performance.