The Best-of-2-Worlds philosophy: Developing local dismantling and global infrastructure network for sustainable e-waste treatment in emerging economies

E-waste is a complex waste category containing both hazardous and valuable substances. It demands for a cost-efficient treatment system which simultaneously liberates and refines target fractions in an environmentally sound way. In most developing countries there is a lack of systems covering all steps from disposal until final processing due to limited infrastructure and access to technologies and investment. This paper introduces the ‘Best-of-2-Worlds’ philosophy (Bo2W), which provides a network and pragmatic solution for e-waste treatment in emerging economies. It seeks technical and logistic integration of ‘best’ pre-processing in developing countries to manually dismantle e-waste and ‘best’ end-processing to treat hazardous and complex fractions in international state-of-the-art end-processing facilities. A series of dismantling trials was conducted on waste desktop computers, IT equipment, large and small household appliances, in order to compare the environmental and economic performances of the Bo2W philosophy with other conventional recycling scenarios. The assessment showed that the performance of the Bo2W scenario is more eco-efficient than mechanical separation scenarios and other local treatment solutions. For equipment containing substantial hazardous substances, it demands the assistance from domestic legislation for mandatory removal and safe handling of such fractions together with proper financing to cover the costs. Experience from Bo2W pilot projects in China and India highlighted key societal factors influencing successful implementation. These include market size, informal competitors, availability of national e-waste legislation, formal take-back systems, financing and trust between industrial players. The Bo2W philosophy can serve as a pragmatic and environmentally responsible transition before establishment of end-processing facilities in developing countries is made feasible. The executive models of Bo2W should be flexibly differentiated for various countries by adjusting to local conditions related to operational scale, level of centralized operations, dismantling depth, combination with mechanical processing and optimized logistics to international end-processors.     

Earthworm additions affect leachate production and nitrogen losses in typical midwestern agroecosystems

Earthworms affect soil structure and the movement of agrochemicals. Yet, there have been few field-scale studies that quantify the effect of earthworms on dissolved nitrogen fluxes in agroecosystems. We investigated the influence of semi-annual earthworm additions on leachate production and quality in different row crop agroecosystems. Chisel-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation (CT) and ridge-till corn-soybean-wheat (Triticum aestivum L.) rotation (RT) plots were arranged in a complete randomized block design (n = 3) with earthworm treatments (addition and ambient) as subplots where zero-tension lysimeters were placed 45 cm below ground. We assessed earthworm populations semi-annually and collected leachate biweekly over a three-year period and determined leachate volume and concentrations of total inorganic nitrogen (TIN) and dissolved organic nitrogen (DON). Abundance of deep-burrowing earthworms was increased in addition treatments over ambient and for both agroecosystems. Leachate loss was similar among agroecosystems, but earthworm additions increased leachate production in the range of 4.5 to 45.2% above ambient in CT cropping. Although leachate TIN and DON concentrations were generally similar between agroecosystems or earthworm treatments, transport of TIN was significantly increased in addition treatments over ambient in CT cropping due to increased leachate volume. Losses of total nitrogen in leachate loadings were up to approximately 10% of agroecosystem N inputs. The coincidence of (i) soluble N production and availability and (ii) preferential leaching pathways formed by deep-burrowing earthworms thereby increased N losses from the CT agroecosystem at the 45-cm depth. Processing of N compounds and transport in soil water from RT cropping were more affected by management phase and largely independent of earthworm activity.     

Biological monitoring of aromatic diisocyanates in workers exposed to thermal degradation products of polyurethanes

Exposure to diisocyanates was assessed by biological monitoring among workers exposed to the thermal degradation products of polyurethanes (PURs) in five PUR-processing environments. The processes included grinding and welding in car repair shops, milling and turning of PUR-coated metal cylinders, injection moulding of thermoplastic PUR, welding and cutting of PUR-insulated district heating pipes during installation and joint welding, and heat-flexing of PUR floor covering. Isocyanate-derived amines in acid-hydrolysed urine samples were analysed as perfluoroacylated derivatives by gas chromatography mass spectrometry in negative chemical ionisation mode. The limits of quantification (LOQs) for the aromatic diamines 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA) and 4,4'-methylenedianiline (4,4'-MDA) were 0.25 nmol l(-1), 0.25 nmol l(-1) and 0.15 nmol l(-1), respectively. The LOQ for the aliphatic diamines hexamethylenediamine (HDA), isophoronediamine (IpDA) and 4,4'-diaminodicyclohexyl methane (4,4'-DDHM) was 5 nmol l(-1). TDA and MDA were detected in urine samples from workers in car repair shops and MDA in samples from workers welding district heating pipes. The 2,4-TDA isomer accounted for about 80% of the total TDA detected. No 2.6-TDA was found in the urine of non-exposed workers. The highest measured urinary TDA and MDA concentrations were 0.79 nmol mmol(-1) creatinine and 3.1 nmol mmol(-1) creatinine, respectively. The concentrations found among non-exposed workers were 0.08 nmol mmol(-1) creatinine for TDA and 0.05 nmol mmol(-1) creatinine for MDA (arithmetic means). Exposure to diisocyanates originating from the thermal degradation of PURs are often intermittent and of short duration. Nevertheless, exposure to aromatic diisocyanates can be identified by monitoring diisocyanate-derived amines in acid-hydrolysed urine samples.     

Monitoring priority substances of directives 76/464/EEC and 2000/60/EC in Greek water bodies

The priority substances of List I, 76/464/EEC Directive, some of which belong to the new Water Framework Directive 2000/60/EC, have been monitored in the surface waters of Greece through the developed network of 53 sampling stations. The analytical methods used for the determination of these substances included Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds, Gas Chromatography-Electron Capture Detection for organochlorine insecticides, High Performance Liquid Chromatography for pentachlorophenol and Atomic Absorption Spectrometry for metals. The results have shown the presence of several priority substances in Greek surface waters, in most cases at concentrations well below the regulatory limits. However, non-compliance was observed for a limited number of compounds. The monitoring network and the analytical determinations have to be expanded to more water bodies and more priority substances, in order to safeguard the quality of Greek surface waters.     

Work status and organizational citizenship behavior: a field study of restaurant employees

This survey‐based field study of 257 service employees developed and tested a model of differences in the organizational citizenship behavior of full‐time and part‐time employees based on social exchange theory. Questionnaire data from matched pairs of employees and their supervisors demonstrated that part‐time employees exhibited less helping organizational citizenship behavior than full‐time employees, but there was no difference in their voice behavior. We also predicted that both preferred work status (an individual factor) and organizational culture (a contextual factor) would moderate the relationships between work status and citizenship. For helping, results demonstrated that preferred status mattered more to part‐time workers than to full‐time. For voice, preferred work status was equally important to part‐time and full‐time workers, such that voice was high only when actual status matched preferred status. Contrary to our expectations, work status made more of a difference in both helping and voice in less bureaucratic organizations. We discuss the implications of work status for social exchange relationships, differences in the social exchange costs and benefits of helping compared to voice, and ramifications of our findings for future research. Copyright © 2001 John Wiley & Sons, Ltd.     

Predispersal seed herbivores, not pollinators, exert selection on floral traits via female fitness

Herbivores that oviposit in flowers of animal-pollinated plants depend on pollinators for seed production and are therefore expected to choose flowers that attract pollinators. This provides a mechanism by which seed herbivores and pollinators could impose conflicting selection on floral traits. We measured phenotypic selection on floral traits of Lobelia siphilitica (Lobeliaceae) via female fitness to determine the relative strength of selection by pollinators and a specialist predispersal seed herbivore. We were able to attribute selection on flowering phenology to the herbivores. However, no selection could be attributed to pollinators, resulting in no conflicting selection on floral traits. Unlike pollinators, whose preference for certain floral traits does not always translate into higher fitness, any discrimination by seed herbivores is likely to decrease fitness of the preferred floral phenotype. Thus predispersal seed herbivores may be a significant agent of selection on floral traits.     

Development and Validation of an Aquatic Fine Sediment Biotic Index

The Fine Sediment Biotic Index (FSBI) is a regional, stressor-specific biomonitoring index to assess fine sediment (<2 mm) impacts on macroinvertebrate communities in northwestern US streams. We examined previously collected data of benthic macroinvertebrate assemblages and substrate particle sizes for 1,139 streams spanning 16 western US Level III Ecoregions to determine macroinvertebrate sensitivity (mostly at species level) to fine sediment. We developed FSBI for four ecoregion groupings that include nine of the ecoregions. The grouping were: the Coast (Coast Range ecoregion) (136 streams), Northern Mountains (Cascades, N. Rockies, ID Batholith ecoregions) (428 streams), Rockies (Middle Rockies, Southern Rockies ecoregions) (199 streams), and Basin and Plains (Columbia Plateau, Snake River Basin, Northern Basin and Range ecoregions) (262 streams). We excluded rare taxa and taxa identified at coarse taxonomic levels, including Chironomidae. This reduced the 685 taxa from all data sets to 206. Of these 93 exhibited some sensitivity to fine sediment which we classified into four categories: extremely, very, moderately, and slightly sensitive; containing 11, 22, 30, and 30 taxa, respectively. Categories were weighted and a FSBI score calculated by summing the sensitive taxa found in a stream. There were no orders or families that were solely sensitive or resistant to fine sediment. Although, among the three orders commonly regarded as indicators of high water quality, the Plecoptera (5), Trichoptera (3), and Ephemeroptera (2) contained all but one of the species or species groups classified as extremely sensitive. Index validation with an independent data set of 255 streams found FSBI scores to accurately predict both high and low levels of measured fine sediment.