Arrangements for Mineral Development Cooperation between Socialist Countries and Developing Countries

To obtain those fuels and minerals which cannot be supplied from intra-CMEA sources, the European CMEA countries have resorted to compensation agreements, long-term supply agreements, and joint venture with the developing countries. Examples of these are given. In the future the European CMEA countries will need to rely increasingly on the developing countries for supplies of raw materials. The reasons for this are examined and new forms of East-South co-operation aré explored.
Pour obtenir ceux des carburants et des mineraux qui ne peuvent pas leur être livrés en provenance de fournisseurs internes du Conseil d'assistance d'économique mutuelle (CAEM), les pays européens du CAEM ont fait appel à des ententes de compensation, à des ententes de livraison à long terme et à des operations conjointes avec des pays en voie de développement. Des exemples sont donnés. Les pays européens de CAEM seront amenés, dans les années à venir, à dependre de plus en plus des pays en voie de développement pour les fournitures en maitières premieres. Les raisons correspondantes sont passées en revue et des formules nouvelles de cooperation est-sud sont explorées.
Para abastecerse de combustible s y minerales que no pueden ser suministros de fuentes de los países del Consejo de Asistencia Económica Mutua (CAEM), los países europeos de CAEM estan utilizando acuerdos de compensación, contratos a largo plazo e inversiones conjuntas con los países en desarrollo. En este artículo se dan ejemplos de estos contratos. En el futuro los países europeos de CAEM dependerán en el suministro de recursos naturales por los países en desarrollo. Se examinan las razones para esta creciente dependencia y se exploran nuevas formas de cooperación Este-Sur.     

Cleanup of biological extracts by a Pasteur pipette column and a comparison of in vivo-accumulated chlorinated pesticide residues with other clean up systems

Biological samples are extracted with n-hexane/acetone (60:40) and 1 mL of the concentrated extract is eluted through a pasteur pipette column prepacked with alumina (0.3 g) and silicic acid (0.25 g) with 10 mL n-hexane (containing 4% acetone). The fat and other co-extractives are retained by the column and clear eluate is directly injected on a GLC column for determination on electron capture detector. A comparison of the Pasteur pipette cleanup with the modified method of Cole et al. (1967) on 41 samples of fish, One Step Method, (Ahmad and Marolt (1986] on 86 samples of fish and Maunder et al. (1964) on 10 type of wildlife (100 samples) was made. The Pasteur pipette method gives results which are significantly higher (p greater than 0.5) than the other methods except the One step method. The Pasteur pipette method has a detection limit of 0.01 microgram/g for DDT and its metabolites.     

Neurotoxicity of organophosphorus insecticides Leptophos and EPN.

Phosfolan, chlorpyrifos, and stirophos when applied to white mice at sublethal doses did not induce any delayed neurotoxic effect. On the other hand, Leptophos and EPN when administered orally at sublethal or lethal levels clearly produced a delayed neurotoxic ataxia in treated mice. The five tested organophosphorus insecticides were compared for their ability to inhibit cholinesterase, neurotoxic esterases and monoamine oxidase. I50 values were estimated for each case. The results revealed that all five compounds were inhibitors of cholinesterase, but only Leptophos and EPN were shown to be potent inhibitors for both neurotoxic esterase and monoamine oxidase in the mouse brain. Additional particular properties of both Leptophos and EPN were found in their ability to cause delayed neurotoxic ataxia in chickens and sheep fed once on sublethal doses of these compounds. It is believed that the phosphonate ester configuration of EPN and Leptophos has a specific mode of toxic action which is mainly located at the central nervous system. It is also postulated that these delayed neurotoxic agents might inhibit postganglionic sympathetic neurons, thus resulting in chronic paralytic effects.     

Evolution and Reform: The Art of Transition in Energy Pricing Policy

This paper presents an analysis of potential methods of reform of petroleum pricing policies in developing countries. It takes as given the highly political nature of petroleum pricing in selected developing countries (including Brazil. Ecuador, Argentina, the Sudan and Republic of Korea), and identifies several models for reform.     

Volatilization of lindance from water in soil-free and flooded soil systems.

Volatilization of 14C-lindane from water in planchets and under flooded soil ecosystem was investigated. Lindane disappeared faster than parathion from planchets. More rapid loss of both insecticides occurred from water than from chloroform. Loss of lindane and parathion was related to measured losses of water by evaporation. During 5-day incubation under flooded soil conditions, disappearance of lindane was faster from open vials than from sealed vials, whereas in nonflooded soil, no volatile loss of the insecticide was evident despite water evaporation. Over 5 day incubation under flooded conditions, greater volatile loss of lindane occurred in sandy soil than in alluvial soil apparanetly due to greater adsorption to the soil colloids decreasing the insecticide concentration in the standing water on the laterite soil. Under identical conditions of water evaporation, lindane loss was directly proportional to its initial concentration in the water. These results suggest that considerable loss of soil applied pesticides can occur by volatilization from the standing water in flooded rice fields, particularly under tropical conditions.     

Acute toxicity of two insecticides to tubificid worms, Tubifex tubifex and Limnodrilus hoffmeisteri

Acute toxicity and presumable harmless concentration of two commercial insecticides, Furadan 3G and Malataf 50E were reported for tubificid worms, Tubifex tubifex and Limnodrilus hoffmeisteri. L. hoffmeisteri were found more susceptible to both the insecticides; the Furadan was found to be more toxic than Malataf to tubificid worms. Analysis of variants showed a significant difference between safe concentrations of the same insecticide to different species.     

Arsenic in ground-water under oxidizing conditions,south-west United States

Concentrations of dissolved arsenic in ground-water in alluvial basins of Arizona commonly exceed 50 g L^–1 and reach values as large as 1,300 g L^–1. Arsenic speciation analyses show that arsenic occurs in the fully oxidized state of plus 5 (As+5), most likely in the form of HAsO4², under existing oxidizing and pH conditions. Arsenic in source areas presumably is oxidized to soluble As before transport into the basin or, if after transport, before burial. Probable sources of arsenic are the sulphide and arsenide deposits in the mineralized areas of the mountains surrounding the basins. Arsenic content of alluvial material ranged from 2 to 88 ppm. Occurrence and removal of arsenic in ground-water are related to the pH and the redox condition of the ground-water, the oxidation state of arsenic, and sorption or exchange. Within basins, dissolved arsenic correlates (P<0.01) with dissolved molybdenum, selenium, vanadium, and fluoride and with pH, suggesting sorption of negative ions. The sorption hypothesis is further supported by enrichment of teachable arsenic in the basin-fill sediments by about tenfold relative to the crustal abundance and by as much as a thousandfold relative to concentrations found in ground-water. Silicate hydrolysis reactions, as defined within the alluvial basins, under closed conditions cause increases in pH basinward and would promote desorption. Within the region, large concentrations of arsenic are commonly associated with the central parts of basins whose chemistries evolve under closed conditions. Arsenic does not correlate with dissolved iron (r = 0.09) but may be partly controlled by iron in the solid phase. High solid-phase arsenic contents were found in red clay beds. Large concentrations of arsenic also were found in water associated with red clay beds. Basins that contain the larger concentrations are bounded primarily by basalt and andesite, suggesting that the iron content as well as the arsenic content of the basin fill may play a role in the occurrence of arsenic in ground-water. Under oxidizing conditions in Arizona, arsenic in ground-water appears to be controlled in part by sorption or desorption of HAsO4² on active ferric oxyhydroxide surfaces.