Airborne Emissions of Mercury from Municipal Solid Waste. II: Potential Losses of Airborne Mercury before Landfill

Abstract

Waste distribution and compaction at the working face of municipal waste landfills releases mercury vapor (Hg⁰) to the atmosphere, as does the flaring of landfill gas. Waste storage and processing before its addition to the landfill also has the potential to release Hg⁰ to the air if it is initially present or formed by chemical reduction of Hg^II to Hg⁰ within collected waste. We measured the release of Hg vapor to the atmosphere during dumpster and transfer station activities and waste storage before landfilling at a municipal landfill operation in central Florida. We also quantified the potential contribution of specific Hg-bearing wastes, including mercury (Hg) thermometers and fluorescent bulbs, and searched for primary Hg sources in sorted wastes at three different landfills. Surprisingly large fluxes were estimated for Hg losses at transfer facilities (～100 mg/hr) and from dumpsters in the field (～30 mg/hr for 1,000 dumpsters), suggesting that Hg emissions occurring before landfilling may constitute a significant fraction of the total emission from the disposal/landfill cycle and a need for more measurements on these sources. Reducing conditions of landfill burial were obviously not needed to generate strong Hg⁰ signals, indicating that much of the Hg was already present in a metallic (Hg⁰) form. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg⁰, the entire waste mass acts as a source. Broken fluorescent bulbs and thermometers in dumpsters emitted Hg⁰ at 10 to >100 μg/hr and continued to act as near constant sources for several days.     

Self‐protective reactions to peer abusive supervision: The moderating role of prevention focus and the mediating role of performance instrumentality

Across 3 studies, we apply a self‐protection perspective of observed mistreatment to examine a moderated mediation model on “when” and “why” third parties are motivated by peer abusive supervision. We hypothesize that prevention‐focused third parties will increase their performance effort as a response to peer abusive supervision, and this effect is mediated by performance instrumentality. In a field study of working adults (Study 1) and an experimental study that manipulated peer abusive supervision (Study 2), we found that peer abusive supervision interacted with third parties' prevention focus to predict their performance effort such that peer abuse was positively related to third parties' performance effort only for those high on prevention focus. Results were replicated in a second field study of working adults (Study 3). Further, we found support for the mediating effect of performance instrumentality. The theoretical and practical implications of our results are discussed.     

Waste rechargeable electric lamps: characterisation and recovery of lead from their lead-acid batteries

Electrical electronics constitute a significant quantity of municipal solid wastes which are discarded after use in open dumpsites especially in the developing countries. The aim of this study was to characterise the material and chemical components, evaluate current management practices and investigate recovery of lead from battery electrodes (BEs) of waste rechargeable electric lamps (RLs). Twenty-six waste RLs of different models were sampled in Nigeria and characterised. Their BEs were analysed for Pb, Cr, Mn, Cu, Zn, Ni and Fe after acid digestion. Questionnaires were distributed to unselected respondents to assess usage and disposal of the lamps. Reaction of citric acid solutions with Pb in the presence of H₂O₂ was used for the recovery of Pb. 69 % of the respondents disposed their waste RLs in open dumpsites. The mean ± SD concentrations of Pb, Cr, Mn, Cu, Zn, Ni and Fe in the BEs were 600 ± 0.2 g/kg, 65.4 ± 40 mg/kg, 5.05 ± 4.0 mg/kg, 6.81 ± 5.0 mg/kg, 5.98 ± 3.0 mg/kg, 50.0 ± 30 mg/kg and 40.2 ± 35 mg/kg, respectively. The results show that the batteries are lead-acid batteries which require management. At the optimal conditions of S/L = 0.14, temperature = 20 °C and leaching time = 5 h, about 95 % Pb was recovered in form of lead citrate from the battery. High recovery of Pb is possible with simple and environment-friendly reactions.     

Gainsharing and women's and men's relative pay satisfaction

There is some evidence that women have equal or higher pay satisfaction than similarly situated men, even though they may earn less than these men. Using Major's (1994) model of entitlement, this study examined gender differences in pay satisfaction in two companies before and after gainsharing bonus programmes were introduced. Results indicated that women had higher pay satisfaction than men prior to the introduction of gainsharing and there was some evidence that this difference was greater among lower‐paid employees. Women did not exhibit higher pay satisfaction after gainsharing was introduced. The potential association of gainsharing with changes in female–male pay satisfaction is discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Efficient adsorption of carbon dioxide and methane on activated carbon prepared from glycerol with potassium acetate

In the context of global warming and the energy crisis, emissions to the atmosphere of greenhouse gases such as carbon dioxide (CO₂) and methane (CH₄) should be reduced, and biomethane from landfill biogas should be recycled. For this, there is a need for affordable technologies to capture carbon dioxide, such as adsorption of biogas on activated carbon produced from industrial wastes. Here we converted glycerol, a largely available by-product from biodiesel production, into activated carbon with the first use of potassium acetate as an activating agent. We studied adsorption of CO₂ and CH₄ on activated carbon. The results show that activated carbon adsorb CO₂ up to 20% activated carbon weight at 250 kPa, and 9% at atmospheric pressure. This is explained by high specific surface areas up to 1115 m²g⁻¹. Moreover, selectivity values up to 10.6 are observed for the separation of CO₂/CH₄. We also found that the equivalent CO₂ emissions from activated carbon synthesis are easily neutralized by their use, even in a small biogas production unit.

     

Non-metallic organic dyes as photosensitizers for dye-sensitized solar cells: a review

Environmental Science and Pollution Research - The advent of novel technologies has led to the need for environmental and economic integration. Energy consumption plays a vital role in human...     

Polybrominated diphenyl ethers (PBDE) in serum: findings from a US cohort of consumers of sport-caught fish

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in foams, fabrics and plastics, and are common contaminants of household air and dust and bioaccumulate in wildlife, and are detectable in human tissues and in fish and animal food products. In the Great Lakes Basin sport fish consumption has been demonstrated to be an important source of PCB and DDE exposure. PBDEs are present in the same sport fish but prior to our study the contribution to human PBDE body burdens from Great Lakes sport fish consumption had not been investigated. This study was designed to assess PBDE, PCB and 1,1-bis(4-chlorophenyl)-2,2-dichloroethene (DDE) serum concentrations in an existing cohort of 508 frequent and infrequent consumers of sport-caught fish living in five Great Lake states. BDE congeners 47 and 99 were identified in the majority of blood samples, 98% and 62% respectively. summation operatorPBDE levels were positively associated with age, hours spent outdoors, DDE, summation operatorPCB, years of sportfish consumption, and catfish and shellfish intake, and negatively associated with income and recent weight loss. Other dietary components collected were not predictive of measured summation operatorPBDE levels. In multivariate models, summation operatorPBDE levels were positively associated with age, years consuming sport fish, shellfish meals, and computer use and negatively associated with recent weight loss. Having summation operatorPBDE levels in the highest quintile was independently associated with older age, male gender, consumption of catfish and shellfish, computer use and spending less time indoors. summation operatorPCB and DDE were strongly associated suggesting common exposure routes. The association between summation operatorPBDE and summation operatorPCB or DDE was much weaker and modeling suggested more diverse PBDE sources with few identified multi-contaminant-shared exposure routes. In our cohort Great Lakes sport fish consumption does not contribute strongly to PBDE exposure.     

A Benefit‐Cost Analysis of Total Maximum Daily Load Implementation1

Abstract: Total Maximum Daily Load (TMDL) implementation generates benefits and costs from water quality improvements, which are rarely quantified. This analysis examines a TMDL written to address bacteria and aquatic‐life‐use impairments on Abrams and Opequon Creeks in Virginia. Benefits were estimated using a contingent valuation survey of local residents. Costs were based on the number and type of best management practices (BMPs) necessary to achieve TMDL pollution reduction goals. BMPs were quantified using watershed‐scale water quality simulation models (Generalized Watershed Loading Function and Hydrological Simulation Program‐FORTRAN). Based on our projections, the costs to achieve TMDL induced pollution reduction goals outweigh the estimated benefits. Benefit‐cost ratios ranged between 0.1 and 0.3.