Reducing mercury pollution from artisanal gold mining in Munhena,Mozambique

Artisanal small-scale mining (ASM) is responsible for over 90% of gold production in Mozambique. In 2005, a 15-day pilot training project was held in the village of Munhena, a gold mining community. This intervention aimed at raising awareness related to the environmental and health impacts of mercury amalgamation and introduced alternative practices to reduce mercury release and exposure. In 2007, a 9-day evaluation of the pilot campaign was accomplished and knowledge in regards to mining methods, and the ASM government–community operating relations in Munhena were updated. Miners in Munhena are organized in an association of over 3000 members, work on a 25 year Government granted 143 ha concession and generate a substantial income (producing over 5 kg of gold per month). There remain, however, serious barriers towards sustainable community development. ASM associated environmental and health costs are high, as mercury continues to be used and lost to the environment, and cyanide will be introduced soon. The Government of Mozambique has laid the foundation for supporting this sector; however, resources are limited, and thus restrict ability to fully address these issues. Importantly, malaria and HIV/AIDS are not diagnosed and/or treated effectively within the community, and basic necessities are absent. This paper concludes with recommendations focused on enhancing the ASM sector in Mozambique, and overcoming barriers to sustainability in the community of Munhena.     

Towards a new system of environmental governance

Summary Planning, the visible hand of government, is the resource allocation sphere that has the potential to prevent destructive conflict over resources, by creating a long term, rational, ethics-based and participatory decision-making process. Other public decision-making systems (the market, legal and political arenas), by their very nature, cannot adequately protect the environment or ensure sustainable development. However, as presently conceived, Planning⁺ cannot do so either. Reform has been impeded by an ideological bias which defines Planning as diametrically opposed to the market, such that creative alternatives to the two systems of social choice have not been developed.To address this problem, a new tri-partite structure of environmental governance is proposed. Based on an ecofeminist paradigm, it is primarily designed to constrain the potential for the abuse of power, and allow society to address environmental (ethical) as well as social (distributional) and economic (efficiency) issues. In a sense, it rationalises the social decision-making system by re-aligning rights, wants and needs with the appropriate decision-making forum (representative democracy, the market and Planning respectively). The model exposes the need to redesign all these institutions so that they better correspond to their logical functions within the resource allocation system. However, this paper focuses on the Planning system itself.Janis Birkeland was an attorney, architect and planner in San Francisco, USA. She now teaches at the Department of Architecture, University of Tasmania. This article is drawn from a longer 1990 paper Myths and Realities of Planning and Resource Allocation (Department of Geography and Environmental Studies, University of Tasmania), which was presented at the Socialist Scholars' Conference, Melbourne, 18th July, 1991.     

Cyanidation of mercury-rich tailings in artisanal and small-scale gold mining: identifying strategies to manage environmental risks in Southern Ecuador

In many countries, such as Brazil, Colombia, Ecuador, Indonesia, Venezuela and Zimbabwe, amalgamated tailings are leached with cyanide to recover remaining gold. This paper describes a recently completed study conducted at seven gold processing centers in Portovelo-Zaruma, Southern Ecuador, which involved consultation with local miners. The objective of the study was to understand the behaviour of mercury (with a focus on mercury loss) in artisanal gold mining operations through the evaluation of two cyanidation processes (Merrill-Crowe and Carbon-in-pulp), using a participatory approach. In order to assess the kinetics of mercury dissolution in cyanide, a bottle roll test was conducted in the laboratory. In the Merrill-Crowe cyanidation process, an average of 24.2% of metallic mercury was determined to be trapped at the bottom of the agitation tanks; 33.1% of mercury is lost in association with solid material and 11.7% is lost in solution. Approximately 31.0% of mercury in solution is sent to the zinc precipitation cells from which 27.8% is precipitated on the zinc shavings, with 3.23% remaining in solution. The mercury precipitated on to the zinc is lost to the atmosphere when the shavings are burned at 900 °C. In the Carbon-in-pulp (CIP) leaching system, 11.2% of the mercury is lost with the solid tailings; 31.6% of the mercury is associated with fine particles in suspension and 50.8% is likely dissolved. About 2.68% is trapped at the bottom of the tank and 3.72% is absorbed by the activated carbon. The bottle roll test revealed that mercury dissolution is directly proportional to cyanide concentration. At 10 g/ton of cyanide, approximately 42% of mercury was leached, whereas all gold was solubilized. During this study, miners recognized the risk associated with the cyanidation of mercury-rich tailings, and were aware of how much mercury is discharged to local streams and to the atmosphere. The active participation of miners in this study has led to the strengthening of their knowledge and awareness of mercury contamination, and has enhanced their understanding of the nature of the problem, as well as the weaknesses and strengths of the system they operate.     

Scaling the quality of teammates' mental models: equifinality and normative comparisons

We tested the impact of teammates' team and task mental model sharedness on team processes and performance using 70 undergraduate teams that completed a series of missions on a PC‐based flight simulator. Moreover, we considered how the quality of mental models might moderate such relationships. Team processes were found to partially mediate the relationship between task mental model sharedness and team performance. Although team mental model sharedness failed to exhibit a significant linear relationship with team processes or performance, it did evidence a multiplicative relationship as moderated by the quality of those models. Team processes and performance were better among teams sharing higher‐quality team mental models than among teams evidencing less sharedness or who had lower‐quality models. Again, team processes partially mediated these relationships. Results are discussed in terms of the equifinality of mental model quality and applications to various team environments. Copyright © 2005 John Wiley & Sons, Ltd.     

Ökotoxikologische Wirkungen von Teeröl-imprägnierten Holzpfählen

Aim and Scope

This study was aimed at evaluating environmental effects of tar-oil impregnated (tanalized) tree stakes using simple and efficient biotests to obtain results of its ecological impacts during the tar-oil breakdown in the stake.

Results

1. Soil respiration was measured in-situ as an indication of soil microbial activity in two field trials. Soil respiration was measured in a 20 year-old apple orchard at various distances from the tar-oil impregnated tree stakes and also on soil mixed with chippings from pine stakes with tar-oil impregnation of different ages.
2. Cress germination tests were employed to evaluate tar-oil phytotoxicity in a field and laboratory trial. Cress was seeded close to tree stakes in the same 20 year-old apple orchard and germination rates related to tar oil-impregnation. Cress was also seeded in trays in sand mixed with pine chippings from stakes with tar-oil impregnation of different ages.
3. The portion of the carcinogenic benzoapyrene (BaP) ranged between 0.0015% in freshly tar-oil impregnated to 0.4% in tar-oil impregnated 20-year old trees stakes, i.e. irrespective of the overall PAK concentration and its degradation.
4. Kinetic analysis using DIXON plots showed a 50% breakdown of overall PAHs after ca. 2.7 years, i.e. km or Ki values of less than 3 years.

Conclusion

Germination tests of cress and endogenous seeds as well as soil respiration proved sensible indicators of the phytotoxicity and ecotoxicity of tar-oil impregnated tree stakes in fruit orchards. Soil respiration proved particularly sensitive to tar-oil ageing. Its combination with kinetic inhibition models resulted in parameters suitable for the interpretation of results.     

Biological evaluation of SZI‐121, a new miticide

Abstract

A large number of tetrazine analogues were synthetised and tested as miticides. A comprehensive screening system was applied to recognise some effects important in terms of field performance. A promising new substance, coded as SZI‐121 was choosen for further development. It proved to be about four‐times more active as an ovicide (LC₅₀=0.05 ppm) than the reference clofentezine, when administered to the eggs directly (LC₅₀=0.23 ppm). In contrast to clofentezine which has solely a contact mode of action, SZI‐121 has excelent translaminar activity acting on already laid eggs (LC₅₀= 18.66 ppm) or those in females feeding on the opposite, non‐treated side of the leaf (LC₅₀=5.11 ppm). High toxicity of SZI‐121 to the chrysalis form (LC₅₀=0.39 ppm) was also observed. The field rate of SZI‐121 is 60–100 g a.i./ha against a wide range of phytophagous mites including European red mite (Panonychus ulmi), two spotted spider mite (Tetranychus urticae), grape leaf rust mite (Calepitrimerus vitis), vine leaf blister mite (Colomerus vitis), apple leaf rust mite (Aculus schlechtendali), stone fruit leaf rust mite (Vasates fockeui). Because it stops the development of mites in egg and chrysalis forms simultaneously, SZI‐121 can be used independently from actual development stages of mites during the whole season as the field trials demonstrated. These characteristics permit SZI‐121 to be easily fitted into integrated pest management.     

Depressed prostaglandins and leukotrienes in veterans with Gulf War illness

Background: There is need to understand biological markers and mechanisms in Gulf War illness (GWI).

Goal: To examine whether and how eicosanoids – prostaglandins and leukotrienes – are altered in veterans with GWI.

Methods: Seventy participants including 37 GWI and 33 healthy controls, shared exposure information, and had plasma eicosanoids assessed – prostaglandin F2 alpha (pgf2α), prostaglandin D2 (pgd2), leukotriene B4 (lb4) among others. Values were compared for GWI versus controls. Eicosanoid intercorrelations were compared in cases vs. controls. For the most significantly altered eicosanoid in GWI, exposure and symptom relations were assessed.

Results: Prostaglandins and leukotrienes were depressed in GWI, strongest for pgf2α, then lb4. Eicosanoid intercorrelations differed in GWI vs. controls. Fuel-solvent, pesticide, radioactive chemicals and metal exposures related negatively to pgf2α; as, in GWI, did chemical attack and vaccines. Multivariate predictors included fuels-solvents and radioactive chemicals (negative); tetanus vaccine and herbicides (positive). Fuels-solvents and radioactive chemicals predicted lower pgf2α in cases, controls, and all participants controlled for case status. Lower pgf2α related to GWI “Kansas criteria” domains of pain, respiratory, and (borderline significantly) skin symptoms.

Conclusion: Multiple eicosanoids are depressed in GWI, particularly pgf2α and lb4. Prior fuel-solvent exposures, radioactive chemicals, and (in GWI cases) vaccines were linked to lower pgf2α.