Environmental effects of aluminium

Aluminium (Al), when present in high concentrations, has for long been recognised as a toxic agent to aquatic freshwater organisms,i.e. downstream industrial point sources of Al-rich process water. Today the environmental effects of aluminium are mainly a result of acidic precipitation; acidification of catchments leads to increased Al- concentrations in soil solution and freshwaters. Large parts of both the aquatic and terrestrial ecosystems are affected.In the aquatic environment, aluminium acts as a toxic agent on gill-breathing animals such as fish and invertebrates, by causing loss of plasma- and haemolymph ions leading to osmoregulatory failure. In fish, the inorganic (labile) monomeric species of aluminium reduce the activities of gill enzymes important in the active uptake of ions. Aluminium seems also to accumulate in freshwater invertebrates. Dietary organically complexed aluminium, maybe in synergistic effects with other contaminants, may easily be absorbed and interfere with important metabolic processes in mammals and birds.The mycorrhiza and fine root systems of terrestrial plants are adversely affected by high levels of inorganic monomeric aluminium. As in the animals, aluminium seems to have its primary effect on enzyme systems important for the uptake of nutrients. Aluminium can accumulate in plants. Aluminium contaminated invertebrates and plants might thus be a link for aluminium to enter into terrestrial food chains.     

Effect of CeO2 and Al2O3 on the activity of Pd/Co_3O_4/cordierite catalyst in the three-way catalysis reactions (CO/NO/CnHm)

The present article studies the effect of CeO₂ and Al₂O₃ on the activity of Pd/Co₃O₄/cordierite catalyst in conversion of NO, CO, C_nH_m. The catalysts were characterized by temperature programmed reduction with hydrogen, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. It is shown that the effect of CeO₂ on the properties of Pd/Co₃O₄/cordierite catalyst depends on preparation method. The catalyst obtained by co-deposition of cerium and cobalt oxides has higher activity in CO oxidation (CO + O₂ and CO + NO) and total hexane oxidation (C₆H₁₄ + O₂). Such phenomenon is probably caused by more than stoichiometric amount of formed oxygen vacancies, an increase in both mobility of surface oxygen and dispersity of components in the catalytic composition. It is demonstrated that CeO₂ addition promotes the SO₂ resistance of Pd/Co₃O₄/cordierite. The second support decreases the activity of Pd/Co₃O₄/cordierite catalyst in the reactions of CO and C₆H₁₄ with oxygen because of CoAl₂O₄ formation.     

Embryonic and parental preferences for incubation temperature in herring gulls: implications for parent-offspring conflict

According to Trivers (1974), parent-offspring (P-O) conflict arises because offspring are selected to solicit more care than parents are selected to provide. However, should benefits fail to increase with increasing care, the offspring optimum can be reduced to the point where predicted P-O conflict vanishes. We examined offspring demand and parental care in such a benefit-limited system in herring gulls (Larus argentatus). In this species, parents typically neglect their lasthatched (C-) egg during the final hours of hatching (pipped-egg stage), allowing mean temperature to drop by about 4°C, to near 33°C. Other studies indicate that no increased offspring benefit arises from increasing pipped egg incubation temperature above that level, but embryo damage occurs if temperature drops lower. In such a system, P-O conflict over preferred incubation temperature is predicted to be minimal or absent. We assessed phenotypic manifestations of conflict by determining incubation temperature preferences of parent and offspring independently. Temperature provided solely by parental initiative was 33.9°C (artificial eggs, corrected for embryonic heat production). Preferred incubation temperature of pipped embryos was measured by exposing them to moderate chilling (20°C) punctuated by 4-min periods of rewarming when they called. Temperature of vocally thermoregulating embryos stabilized around a mean of 32.9–33.4°C, about 0.5–1.0°C below parental preference. Acting independently, parents and embryos each maintained egg temperature at or near minimum developmentally safe levels. Results provided no evidence for phenotypic conflict, as predicted by a benefit-limited version of Trivers' P-O conflict model. Benefit limitation may also be relevant to P-O conflict in other contexts such as feeding of newly-hatched young.     

Influence of flue-gas desulfurization systems on coal combustion by-product quality at kentucky power stations burning high-sulfur coal

Two Kentucky power plants burning similar blends of high-sulfur western Kentucky and southern Indiana coal provide a unique opportunity to examine the variations in coal combustion by-products due to differences in the method of wet flue-gas desulfurization (FGD). One plant employed carbide lime-based scrubbing for two units and a dual-alkali process for the third unit. The second plant employed a Mississippian limestone from Kentucky for all four units. This study provides an example of optical and SEM petrographic techniques, supplemented by chemical analyses, applied to the study of, at least from the geologic perspective, non-traditional materials. The coal sources comprise a blend of high volatile C and B bituminous, high vitrinite (85–90%, mmf), high-sulfur (> 3%, dry) coals. The fly ash is dominated by glassy phases (70–80%) with about 5–10% spinel (predominately magnetite), 3–10% quartz, and 4–10% isotropic coke comprising the remaining portion of the ash. SEM observations indicate that the glassy particles exhibit a bimodal size distribution with sub-micron glass spheres and a population of larger (several 10s of microns) spheres. The bottom ash has higher proportions of spinels and mullite, with negligible carbon forms, compared to the fly ash from the same units. Fly ashes were observed to be lower in Fe and higher in Al, Si, and S compared to the bottom ashes. Carbide lime, a by-product of acetylene manufacture, soda ash, and limestone were the reagents used in the flue-gas desulfurization processes. The primary FGD by-product is a calcium sulfite slurry which is vacuum filtered and mixed with fly ash and, usually, lime, to form a stable product for disposal. The FGD by-products have some potential, as yet unrealized, for utilization.     

Environmental equity and electric power generation: Disparate community outcomes within Texas?

The examinations conducted in this study focus at the community level to test for disparate outcomes involving utility-based electric power generation within the crucial state of Texas. Potential policy implications are discussed as relevant to the general thesis of environmental racism postulated by justice advocates and the civil rights strategies advanced by justice advocates. Cross-sectional and longitudinal perspectives are used in testing for distributive inequities involving locations of fossil fuel power plants and emissions and output rates of emissions originating from such power plants. These tests provide empirical basis for assessing outcomes of the siting and emissions regulatory processes. While the civil rights strategies that would use Title VI of the Civil Rights Act of 1964 and the disparate impact standard are inapplicable, some limited findings indicate disparate outcomes involving other disadvantaged populations that are difficult to justify in context of legitimate market dynamics. Issues raised in this study have relevance to national energy policy proposals that promote many more power plants across the USA and encourage emissions trading.     

An Ecologically Destabilized Environment: Its Effect on Small-Mammal Populations

Characteristics of the small-mammal populations inhabiting forest biocenoses in the Middle Ural state reserves have been analyzed over in the period from 1987 to 2002. During this period, the habitats of these animals were considerably destabilized due to windfalls and fires. The environmental characteristics of animal microhabitats at different stages of environment destabilization have been described quantitatively. Changes in the long-term cycles of the population dynamics of the dominant forest vole species caused by the destabilizing factors have been found. Redistribution of species dominance with respect to abundance has been demonstrated.     

Molecular biomarkers of energy metabolism in mussels under anthropogenic pollution of Peter the Great Bay, the Sea of Japan

The functional state of the indicator species, the Gray mussel Crenomytilus grayanus (Bivalvia), has been analyzed in five areas of Peter the Great Bay exposed to anthropogenic pollution. The following indices of the state of mussels have been used: molecular biomarkers of energy metabolism—Na⁺,K⁺-ATPase, Mg²⁺-ATPase, and total ATPase activity—as well as the level of lipid peroxidation (LPO) and glutathione concentration in the hepatopancreas, gills, and gonads of mussels. The activity of ATPases, LPO level, and glutathione concentration significantly change in mussels from polluted areas relative to those in mussels from a conventionally unpolluted area (a bay in the Far Eastern State Marine Reserve). The molecular biomarkers used in the study provide reliable information on animal metabolism in impact areas. With consideration of the data obtained, it is concluded that the state of mussels in polluted areas is impaired.