Environmental Ethics Beyond Principle? The Case for a Pragmatic Contextualism

Many nonanthropocentric environmental ethicists subscribe to a ``principle-ist' approach to moral argument, whereby specific natural resource and environmental policy judgments are deduced from the prior articulation of a general moral principle. More often than not, this principle is one requiring the promotion of the intrinsic value of nonhuman nature. Yet there are several problems with this method of moral reasoning, including the short-circuiting of reflective inquiry and the disregard of the complex nature of specific environmental problems and policy arguments. In the present paper, we advance an alternative, pragmatic contextualist approach to environmental ethics, one grounded in the moral theory of John Dewey. We present the results of an empirical study of public environmental ethics and natural resource management attitudes to support our position, and we conclude with a few recommendations for future inquiry in the field of environmental ethics.     

CAN SCRAP SAVE US FROM DEPLETION?

Old scrap constitutes varied proportions of consumption of different metals. The authors construct a model in which the share of scrap in total supply is explained by three factors, the growth rate in overall demand for the metal; the share of metal contained in scrapped products actually recovered; and the durability of metal containing products. The model is used to study the impact on the share of scrap in total supply from changes in each of the factors. The strongest impact appears to follow from changes in the growth rate of overall demand. Inserting empirical data for copper into their model, the authors suggest, for instance, that in the long run old scrap could satisfy 100 per cent of copper demand, provided that this demand contracted by 1 per cent per year. La ferraille constitue des proportions variées d'utilisation de différents métaux. Les auteurs de cet article ont construit un modèle dans lequel la part de ferraille dans 'approvisionnement total est expliquée par le jeu de trois facteurs: le taux de croissance de la demande globale pour le métal, la part de métal contenue dans des débris de métaux effectivement récupérés et la durabilité des métaux renfermant des produits. Le modèle est utilisé pour étudier les incidences des changements dans chacun des facteurs sur la part de ferraille dans 'offre totale. L'incidence la plus importante semble provenir de modifications dans le taux de croissance de la demande globale. En introduisant des données empiriques pour le cuivre dans leur modèle, les auteurs suggèrent par exemple, qu' à longue échéance, la ferraille pourrait répondre à la demande totale en cuivre pourvu que cette demande se réduise d'un pour cent par année. El uso de chatarra representa una proporción variable del consumo de los diferentes metales. En este artículo los autores presentan un modelo en el que la proción de la chatarra en la oferta de un metal depende de tres factores: la tasa de crecimiento de la demanda global del metal, la proción del metal contenido en la chatarra recuperada, y la durabilidad o vida económica de los productos que contienen el metal en cuestión. El modelo se utiliza para estudiar el impacto sobre la proporción de chatarra en la oferta total causado por las variaciónes de cada uno de estos factores. El mayor impacto parece ocurrir debido al cambio en la tasa de crecimiento de la demands global. Al utilizar el modelo con datos para el cobre, los autores sugieren, por ejemplo, que en el largo plazo la chatarra de cobre podría satisfacer el cien por ciento de la demanda de este metal siempre que dicha demanda se contraigo en uno por ciento por año.     

Combined chemical and biological oxidation of penicillin formulation effluent

Antibiotic formulation effluent is well known for its important contribution to environmental pollution due to its fluctuating and recalcitrant nature. In the present study, the chemical treatability of penicillin formulation effluent (average filtered COD(o)=830 mg/l; average soluble COD(o)=615 mg/l; pH(o)=6.9) bearing the active substances penicillin Amoxicillin Trihydrate (C(16)H(19)N(3)O(5)S.3H(2)O) and the beta-lactamase inhibitor Potassium Clavulanate (C(8)H(8)KNO(5)) has been investigated. For this purpose, the penicillin formulation effluent was subjected to ozonation (applied ozone dose=2500 mg/(lxh)) at varying pH (2.5-12.0) and O(3)+H(2)O(2) (perozonation) at different initial H(2)O(2) concentrations (=2-40 mM) and pH 10.5. According to the experimental results, the overall Chemical Oxygen Demand (COD) removal efficiency varied between 10 and 56% for ozonation and 30% (no H(2)O(2)) and 83% (20 mM H(2)O(2)) for the O(3)+H(2)O(2) process. The addition of H(2)O(2) improved the COD removal rates considerably even at the lowest studied H(2)O(2) concentration. An optimum H(2)O(2) concentration of 20 mM existed at which the highest COD removal efficiency and abatement kinetics were obtained. The ozone absorption rate ranged between 53% (ozonation) and 68% (perozonation). An ozone input of 800 mg/l in 20 min was sufficient to achieve the highest BOD(5)/COD (biodegradability) ratio (=0.45) and BOD(5) value (109 mg/l) for the pre-treated penicillin formulation effluent. After the establishment of optimum ozonation and perozonation conditions, mixtures of synthetic domestic wastewater+raw, ozonated and perozonated penicillin formulation effluent were subjected to biological activated sludge treatment at a food-to-microorganisms (F/M) ratio of 0.23 mg COD/(mg MLSSxd), using a consortium of acclimated microorganisms. COD removal efficiencies of the activated sludge process were 71, 81 and 72% for pharmaceutical wastewater containing synthetic domestic wastewater mixed with either raw, ozonated or perozonated formulation effluent, respectively. The ultimate COD value obtained after 24-h biotreatment of the synthetic domestic wastewater+pre-ozonated formulation effluent mixture was around 100 mg/l instead of 180 mg/l which was the final COD obtained for the wastewater mixture containing raw formulation effluent, indicating that pre-ozonation at least partially removed the non-biodegradable COD fraction of the formulation effluent.     

Long-term effects of soil heterogeneity on cadmium behaviour in soil

A deterministic model for long-term behaviour of contaminants in the rootzone is developed that includes sorption, leaching, and plant uptake. The model is applied to cadmium accumulation in a sandy soil and uptake of cadmium by barley. Sensitivity analysis showed that the sensitivity of the leaching rate to changes in soil chemical and soil physical parameters decreases as a function of time, and becomes zero when steady state is reached. In contrast, accumulation of cadmium in soil and the plant uptake rate of barley are increasingly sensitive to soil chemical and soil physical parameters as time preceeds. To analyse cadmium behaviour in a field that is heterogeneous with respect to soil physical properties, the interstitial flow velocity was assumed to be a random, lognormally distributed variate. Using Monte Carlo simulation, the average plant uptake rate appeared to be much higher in the stochastic analysis than in the deterministic approach. Steady state is reached after a very long period of time. For a lognormally distributed proton activity, causing heterogeneity with respect to the sorption capacity of the soil, the model predicted similar deviations from the deterministic approach. It is concluded that reference values for groundwater and crop quality are exceeded earlier in a heterogeneous field than in a homogenous soil profile. Moreover, when average values suggest an acceptable situation, variability of the leaching rate and the plant uptake rate can still cause exceedance of reference values in part of the field. Therefore, it is reasoned that environmental quality standards should take soil heterogeneity into account.     

Assessing chronic toxicity of bisphenol A to larvae of the African clawed frog (Xenopus laevis) in a flow-through exposure system

A number of currently used industrial chemicals are estrogenic, and therefore have potential to disrupt sexual differentiation in vertebrate wildlife during critical developmental windows. We assessed the effect of larval exposure to bisphenol A (BPA) on growth, development and sexual differentiation of the gonad in the African Clawed frog, Xenopus laevis. Larvae were maintained in flow-through conditions at 22 +/- 1 degrees C and exposed to BPA at mean measured concentrations of 0.83, 2.1, 9.5, 23.8, 100, and 497 microg/l, from developmental stages 43/45-66 (completion of metamorphosis). Each test concentration, plus dilution water control (DWC) and positive control (17beta-estradiol (E2), 2.7 microg/l) employed four replicate test vessels with 40 larvae per tank. Individual froglets were removed from test vessels upon reaching stage 66, and the study was terminated at 90 days. Froglets were dissected and sex was determined by inspection of gross gonadal morphology. Test concentrations of BPA had no effect on survival, growth, developmental stage distributions at exposure days 32 and 62, or mean time to completion of metamorphosis, compared to DWC. Analysis of post-metamorphic sex ratio, determined by gross gonadal morphology, indicated no significant deviations from expected (50:50) sex ratio, in DWC or any BPA test concentration. In contrast, exposure of larvae to (E2) resulted in feminisation, with sex ratio deviating significantly (31% male, replicates pooled). Exposure to BPA in the concentration range 0.83-497 microg/l in flow-through conditions had no observable effect on larval growth, development or sexual differentiation (as determined by gross gonadal morphology) in this study.     

Regional landscape-ecological planning and desertification control in arid regions of the Commonwealth of Independent States

Scale-dependent present-day landscape mapping and assessment were used to study the relationship among physical environment, land use, and degree of landscape modification in the Aral Sea region and the Karakum Desert, areas prone to desertification in the Commonwealth of Independent States (CIS). Applying geographic information system (GIS) techniques at global (1:15,000,000), regional (1:1,000,000), and local (1:300,000) scales, researchers found that large-scale landscape assessment and mapping allow them to recognize landscape changes under desertification processes and assess the type and intensity of these processes. Remote sensing has been widely used to evaluate data reliability, to fill information gaps, and to reveal the dynamics of land use types resulting from landscape changes.