Bio-Based Polymers and End-of-Life Vehicles

As new materials, such as bio-based plastics and composites, are introduced in vehicles for their improved environmental performance, it is necessary to understand how to efficiently recover these biodegradable materials. This paper provides an overview of the end-of-life phase for automobiles, focusing on the dismantling and shredding processes, and the recovery of materials. Targeted unit operations, such as dismantling of components from vehicles and pretreatment prior to shredding, along with design-for-environment principles, should enable the efficient recovery of materials at the end-of-life phase compared with popularly conceived all-in-one-approaches because of the diverse arrangement of material components.     

Impacts of biodiesel on pollutant emissions of a JP-8-fueled turbine engine

The impacts of biodiesel on gaseous and particulate matter (PM) emissions of a JP-8-fueled T63 engine were investigated. Jet fuel was blended with the soybean oil-derived methyl ester biofuel at various concentrations and combusted in the turbine engine. The engine was operated at three power settings, namely ground idle, cruise, and takeoff power, to study the impact of the biodiesel at significantly different pressure and temperature conditions. Particulate emissions were characterized by measuring the particle number density (PND; particulate concentration), the particle size distribution, and the total particulate mass. PM samples were collected for offline analysis to obtain information about the effect of the biodiesel on the polycyclic aromatic hydrocarbon (PAH) content. In addition, temperature-programmed oxidation was performed on the collected soot samples to obtain information about the carbonaceous content (elemental or organic). Major and minor gaseous emissions were quantified using a total hydrocarbon analyzer, an oxygen analyzer, and a Fourier Transform IR analyzer. Test results showed the potential of biodiesel to reduce soot emissions in the jet-fueled turbine engine without negatively impacting the engine performance. These reductions, however, were observed only at the higher power settings with relatively high concentrations of biodiesel. Specifically, reductions of approximately 15% in the PND were observed at cruise and takeoff conditions with 20% biodiesel in the jet fuel. At the idle condition, slight increases in PND were observed; however, evidence shows this increase to be the result of condensed uncombusted biodiesel. Most of the gaseous emissions were unaffected under all of the conditions. The biodiesel was observed to have minimal effect on the formation of polycyclic aromatic hydrocarbons during this study. In addition to the combustion results, discussion of the physical and chemical characteristics of the blended fuels obtained using standard American Society for Testing and Materials (ASTM) fuel specifications methods are presented.     

Uptake of polychlorodibenzo-p-dioxins, polychlorodibenzofurans and coplanar polychlorobiphenyls in chickens

Twelve chickens raised according to commercial standards were fed a diet containing about 30 ng total toxic equivalent (TEQ)/kg for 10 weeks. Persistent pollutants were introduced into the poultry feed via recycled oil to mimic contamination conditions closely resembling those occurring during the Belgian crisis five years ago. Absorption of congeners with the same chlorination degree did not seem to depend on the substitution, demonstrating that unlike for cows, no preferential absorption for 2,3,7,8-substituted compounds could be remarked for chickens. As already observed, absorption decreased with increasing number of chlorines and was not linearly dependent on the octanol/water partition coefficient. On the other hand, no real differences were observed in the absorption of coplanar polychlorinated biphenyls (c-PCBs) with regard to degree of chlorination. When monitored during the course of experiment, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and c-PCBs in excreta reached an apparent steady state after 5 weeks. Only 2,3,7,8-substituted dioxins or furans were found in tissues and eggs. All organs showed the same congener profile and similar lipid-normalized concentration, except for the liver. Bioconcentration factors were evaluated, highlighting that the liver preferentially retained highly chlorinated congeners. No depletion of dioxin and PCB concentration was observed after 8 and 14 weeks of control diet, but high inter-individual variation occurs.     

An empirical analysis of a goal setting questionnaire

This research presents an analysis of a goal setting questionnaire developed by Locke and Latham (1984). The Locke and Latham measure attempts to assess the core goal attributes of ‘specificity’ and ‘difficulty’, as well as other attributes of the goal setting process (such as perceptions about ‘performance feedback’, ‘supervisor support’, ‘conflict’ and ‘stress’). The psychometric properties of the measure were examined using respondents from employees of a large, west-coast electronics organization. A principal components analysis extracted 10 meaningful factors and identified a need for additional items. Results generally supported the meaningfulness of the goal setting factors and provide important directions for future research.     

PERCEIVED WATER QUALITY AND THE VALUE OF SEASONAL HOMES1

ABSTRACT: The impact of degraded water quality on the value of seasonal homes adjacent to St. Albans Bay on Lake Champaign in northern Vermont is estimated using hedonic price functions. The Value of properties located adjacent to the bay are depressed by about 20 percent, or $4,500 on average, compared with similar nearby properties on the larger but cleaner lake. Water quality degradation resulted in decressed property values of approximately two million dollars in the area surrounding the Bay.     

IMPACTS OF WATER QUALITY IMPROVEMENT ON SITE VISITATION: A PROBABILISTIC MODELING APPROACH1

ABSTRACT: The influence of perceptions of water quality on the likelihood of recreating at a particular recreation site is investigated using a logit model. The model is estimated for St. Albans Bay, Vermont. A hypothetical improvement in water quality was shown to greatly increase the probability of at least one visit to the bay during a season. This implies that many recreationists who do not use the bay at present will do so if water quality improves. A demand model for predicting site visitation must, therefore, include current nonusers in the sample. Failure to do so would result in misleading predictions about future demand for the bay.     

AGRICULTURAL POLLUTION CONTROL: IMPLICATIONS FROM THE RURAL CLEAN WATER PROGRAM1

ABSTRACT: The Rural Clean Water Program has provided a unique opportunity to study the economics of agricultural nonpoint source pollution control. Several implications for improving the economic efficiency of future agricultural nonpoint source pollution control programs can be drawn from the results. First, individual projects should be targeted towards water bodies that have water quality problems causing economic damages. Considerable variation can exist among areas in the magnitude of economic damages, which may not be proportional to physical impacts. Second, the relative costs and effectiveness of the practices selected to reduce the delivery of pollutants can vary dramatically from one location to another. Early identification and emphasis on cost-effective BMPs can substantially reduce project costs and may make a project economically justifiable that would not otherwise be so. Finally, some projects that do not hive potential economic benefits from water quality improvements exceeding government cost may have on-farm benefits from reduced costs and increased long-term yields that are sufficient to make total benefits (water quality and on-farm) exceed costs.     

SOIL CONSERVATION PRACTICES AND WATER QUALITY: IS EROSION CONTROL THE ANSWER?1

ABSTRACT: This paper is a computer simulation analysis of an agricultural nonpoint pollution problem. Computer modeling is a universally applicable tool that can be used for establishing the linkages between and the quality of agricultural runoff in both surface and subsurface flow. The tradeoffs between the costs of soil conservation practices and water quality are reported, and the economic implications of such tradeoffs are discussed. Soil and nutrient losses resulting from crop production practices are analyzed using a field-scale computer simulation model (CREAMS). No-till planting, reduced tillage, and sod waterway systems are more cost effective than other practices for controlling soil and nutrient runoff losses. Nitrate leaching losses are increased slightly by most soil conservation practices. Terrace systems and permanent vegetative cover impose the greatest societal cost for water quality protection. Public cost sharing and tax incentives encourage farmers to adopt expensive structural practices, and policies are needed to get cost-effective practices implemented on critical acreage. Extensive treatment of land is necessary for agricultural best management practices (BMPs) to significantly improve water quality in areas that are intensively farmed.     

Can we optimize biomonitoring?

Biomonitoring is an element of environmental management that must become more sophisticated to meet the demands of legislation and public concern for environmental safety. Data collection and analysis techniques must improve if environmental scientists are to take full advantage of the information content of field and laboratory biomonitoring efforts. Issues associated with biomonitoring, which we address, include test system selection and the data characteristics of various biomonitoring techniques. We identify optimization as a possible approach to resolving conflicts between legal defensibility, scientific accuracy, and the requirements of environmental managers.     

Ecosystem health: I. Measuring ecosystem health

Ecosystem analysis has been advanced by an improved understanding of how ecosystems are structured and how they function. Ecology has advanced from an emphasis on natural history to consideration of energetics, the relationships and connections between species, hierarchies, and systems theory. Still, we consider ecosystems as entities with a distinctive character and individual characteristics. Ecosystem maintenance and preservation form the objective of impact analysis, hazard evaluation, and other management or regulation activities. In this article we explore an approach to ecosystem analysis which identifies and quantifies factors which define the condition or state of an ecosystem in terms of health criteria. We relate ecosystem health to human/nonhuman animal health and explore the difficulties of defining ecosystem health and suggest criteria which provide a functional definition of state and condition. We suggest that, as has been found in human/nonhuman animal health studies, disease states can be recognized before disease is of clinical magnitude. Example disease states for ecosystems are functionally defined and discussed, together with test systems for their early detection.This article is contribution VI in D.J. Schaeffer's Environmental Audit series.