An analysis of joint costs in a managed forest ecosystem

This paper analyzes the tenability of line item budgeting and independently determined output costs for a managed forest ecosystem. The general problem of cost allocation in a joint production system is discussed as one of choosing paths of integration. A production structure is hypothesized for describing a managed forest ecosystem and its characteristics of “jointness” are discussed. Finally, an empirical case example is presented which indicates that cost estimates and associated means of production which result from single output costing procedures and from joint costing procedures may be significantly different in a managed forest ecosystem.     

Environmental Assessment of Water, Sediment and Plants in the Mankyeong River, ROK

This study was carried out to evaluate water quality, sediment and plant vegetation in eight tributaries of the Mankyeong River for enhancement of natural purification. Among the tributaries, the Iksancheon water had the highest concentration of BOD, T–N and NH₄–N due to inflow of swine wastes from the livestock district. The Yucheon water had the highest level of electrical conductivity and SO ₄ ^2– due to inflow of mis-treated wastewater from industrial districts. The Tabcheon had generally similar concentrations of nitrogen and phosphate to that of the upstream of the Mankyeong River: agricultural activity along the Tabcheon appeared to have little negative influence to the water quality. Among various sediments, concentration of organic matter, nitrogen and phosphate were high in the Iksancheon and the Yucheon due to the livestock wastes and industrial wastes. There were 282 species of plants during summer with 43 aquatic plants, 57 hydrophytes, 178 waterside plants and 4 terrestrial plants. Some plant resources were recommended due to much absorption of nitrogen and phosphate for enhancement of natural purification. C. demersum and H. verticillata were recommended in the submerged aquatic plants, H. dubia, N. indica and N. subinteperrimum in the floating leaf aquatic plants, P. communis, Z. latifolia and T. orientalis in the emerged aquatic plants, C. scutata and P. distichum in the waterside plants.     

Hydrochemical Monitoring and Heavy Metal Contaminations at the Narim Mine Creek in the Sulcheon District, Republic of Korea

The Narim gold mine is located approximately 200km southeast of Seoul within the Sulcheon mineralised district in the Yeongnam massif, Korea. In this study, environmental geochemical analyses were undertaken for soil, sediment and water samples collected in April, September and November in 1998 from the Narim mine creek. The mine area consists mainly of granitic gneiss; however, mineral constituents of soil and sediment near the mine were mainly composed of quartz, feldspar, mica, amphibole, some pyrite and clay minerals. Also were found some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, malachite, goethite, various hydroxide and unidentified secondary minerals. Generally, high concentrations of heavy metals in the soil and sediment are correlated with a high proportion of secondary minerals. Hydrochemical compositions of water samples are characterised by relative significant enrichment of Na⁺+K⁺ and alkali metals in the ground water, whereas the surface and mine waters are relatively enriched in Ca²⁺+Mg²⁺ and heavy metals. Anion contents of the ground waters are typically enriched in HCO₃ ^–, NO₃ ^– and Cl^–, whereas the surface and mine waters are highly enriched in HCO₃ ^– and SO₄ ^2–. The pH and EC values of the surface water from the non-mine creek are relatively lower compared with those of the surface water around the mine and waste dump. The range of D and ¹⁸O values (d parameters) of the water samples are shown in distinct two groups for the April waters of 10.1–13.1, and for the November waters of 5.8–7.9, respectively. This range variation indicates that two group water were composed of distinct waters because of seasonal difference. Geochemical modelling showed that mostly heavy toxic metals may exist largely in the form of free metal (M²⁺) and metal-sulphate (MSO₄ ^2–), and SO₄ ^2– concentration influenced the speciation of heavy metals in the mine water. These metals in the ground water could be formed of CO₃ ^– and OH^– complex ions. Using a computer program, saturation indices of albite, calcite, dolomite in mostly surface water show undersaturated and progressively evolved toward the saturation state, however, ground and mine waters are nearly saturated. The gibbsite, kaolinite and smectite are supersaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that the weathering of silicate minerals may be stable kaolinite. The clay minerals of K-illite and Na-smectite will be transformed to more stable kaolinite owing to the continuous reaction.     

METROPOLITAN GROWTH AND WATER MANAGEMENT IN LATIN AMERICA

This article discusses some recent developments in water management in Latin America. It is based on research done during the joint CEPAL/UNEP project on Water Development and the Environment. The author discusses the changes in water use occurring in Latin America in general, the contemporary relationship with the water resource in four major metropolitan centres, Bogotá, Colombia, Lima, Peru, and Sāo Paulo and Rio de Janeiro, Brazil. On the basis of the general and specific experiences described, general conclusions are drawn as to styles of water management current in the region and adjustments to the problem posed by the emergence of very large metropolitan concentrations of population and economic activity. Cet article reprend des développements récents en matière de gestion des ressources en eau en Amérique latine. II se base sur des recherches effectuées au cours de l'exécution du projet conjoint CEPAL/PNUE sur la mise en valeur des ressources en eau et de l'environnement. L'auteur discute des modifications intervenues dans l'utilisation des ressources en eau en Amérique latine en général et le rapport qui existe actuellement entre les ressources en eau et quatre centres principaux urbains (Bogota en Colombie, Lima au Pérou, et Sāo Paulo et Rio de Janeiro au Brésil). Sur la base des experiences générales et particulières décrites, des conclusions génèrales sont tirées quant aux modes de gestion actuelle des ressources en eau dans la région et aux améliorations apportées au problème créé par l'apparition d'énormes agglomérations urbaines à activité économique intense. Este artículo trata sobre algunos desarrollos recientes en la administración del uso de recursos de agua en Latinoamérica. El artículo está basado en la investigación realizada en el proyecto conjunto CEPAL/PNUMA sobre Desarrollo de Agua y el Medio Ambiente. El autor analiza los cambios que están ocurriendo en el uso de recursos de ague en Latinoamérica en general y las relaciones entre los recursos de agua y los usos en cuatro centros metropolitanos: Bogotá, Lima, Sāco Paulo y Rio de Janeiro. Basándose en descripciones de experiencias generales y específicas, se extraen conclusiones sobre los estilos de la administración de recursos de agua existentes en la región y sobre la solución a los problemas planteados por la emergencia de grandes concentraciones metropolitanas de población y actividad económica.     

Daily intakes of naturally occurring radioisotopes in typical Korean foods

The concentrations of naturally occurring radioisotopes ((232)Th, (228)Th, (230)Th, (228)Ra, (226)Ra, and (40)K) in typical Korean foods were evaluated. The daily intakes of these radioisotopes were calculated by comparing concentrations in typical Korean foods and the daily consumption rates of these foods. Daily intakes were as follows: (232)Th, 0.00-0.23; (228)Th, 0.00-2.04; (230)Th, 0.00-0.26; (228)Ra, 0.02-2.73; (226)Ra, 0.01-4.37 mBq/day; and (40)K, 0.01-5.71 Bq/day. The total daily intake of the naturally occurring radioisotopes measured in this study from food was 39.46 Bq/day. The total annual internal dose resulting from ingestion of radioisotopes in food was 109.83 muSv/y, and the radioisotope with the highest daily intake was (40)K. These values were same level compiled in other countries.     

Hydrometallurgical processing of Nd–Fe–B magnets for Nd purification

An evaluation of various metal purification processes subsequent to the leaching processing of the neodymium (Nd) product from neodymium–iron–boron (Nd–Fe–B) magnets has been conducted. These post-leaching purification processes included precipitation; replacement and electrolysis were studied in order to check the purity of the recovered neodymium. A hydrometallurgical investigation was adopted to digest the metal content of the scrap Nd–Fe–B magnets for the recovery of valuable Nd metal and other metals such as Fe, B, Co and Ni. The effect of leaching conditions such as solid-to-liquid ratio and temperature were optimized and 100 % Nd, 100 % Fe, 100 % B and 85.87 % Co leaching efficiencies were achieved under these conditions. The coating material of the magnet, Ni, achieved 50 % impregnation after increasing the reaction temperature to 70 °C. The metals present in the optimal leaching solution were recovered 99 % by pH adjustment. However, the replacement had the highest separation efficiency for the recovery of Nd metal. Further, the optimal leaching Nd–Fe–B solution was subjected to the electrolysis processes in order to verify the recovery efficiency for all metals.     

Interpreting complex geochemistry of groundwater in a coastal paddy field near a mine using isotopic signatures of sulfate and water

Environmental Geochemistry and Health - In the area around the abandoned Seoseong mine, South Korea, coastal paddy fields undergo seawater intrusion and possible sulfate reduction. Here, channel...     

Biogas productivity of algal residues from bioethanol production

Journal of Material Cycles and Waste Management - The purpose of this study was to investigate biogas productivity of algal residues from bioethanol production. Pre-treatment based on enzyme was...