Geochemical evidence for atmospheric pollution derived from prehistoric copper mining at Copa Hill, Cwmystwyth, mid-Wales, UK.

This paper presents geochemical data from a blanket peat located close to a Bronze Age copper mine on the northern slopes of the Ystwyth valley, Ceredigion, mid-Wales, UK. The research objective was to explore the possibility that the peat contained a geochemical record of the pollution generateD by mining activity. Four peat monoliths were extracted from the blanket peat to reconstruct the pollution history of the prehistoric mine. Three different geochemical measurement techniques were employed and four copper profiles have been reconstructed, two of which are radiocarbon-dated. The radiocarbon dates at one profile located close to the mine confirm that copper enrichment occurs in the peat during the known period of prehistoric mining. Similar enrichment of copper concentrations is shown in one adjacent profile and a profile within 30 m away. In contrast, copper was not enriched in the other radiocarbon-dated monolith, collected approximately 1.35 km to the north of the mine. Whilst other possible explanations to explain the copper concentrations are discussed, it is argued that the high copper concentrations represent evidence of localised atmospheric pollution caused by Bronze Age copper mining in the British Isles. The results of this study suggest that copper may be immobile in blanket peat and such deposits can usefully be used to reconstruct atmospheric pollution histories in former copper mining areas.

Summary of track D: social science: research, policy and action.

SCOPE: This review summarizes the main issues discussed during Track D, which examined the societal impact of HIV/AIDS, and responses to the epidemic by individuals, families, communities and societies worldwide. Micro- and macrolevel issues addressed included the development, implementation and evaluation of programmes for prevention and care; policy development and implementation; structural issues such as the impact of gender relations, development and migration on the development of the epidemic; and the social and economic impact of HIV/AIDS on affected societies and communities. RECURRENT THEMES: Presentations provided strong evidence that peer-led, community-based programmes offer particularly effective ways of working, and that participatory research involving affected communities provides useful results for the design and evaluation of programmes and policies. This is the case across settings, issues, populations and countries. FUTURE DIRECTIONS: Emerging needs include how best to ensure sustainability of national and international responses, how best to scale up successful interventions for wider reach, and how best to work with systematically marginalized, neglected groups and populations. Research priorities include the characterization of the multiple determinants of HIV-related vulnerability, and the evaluation of interventions that take these complex determinants as their starting point. A more coherent and strategic response requires less separation between the different constituencies involved in AIDS work, and the more sustained involvement of people living with HIV/AIDS themselves.

Influence of strain and medium composition on filtration of escherichia coli suspensions.

Cross-flow filtration of Escherichia coli strains was examined at the laboratory and pilot scales using Romicon 500,000 molecular-weight-cutoff hollow fiber membranes. Both the series resistance and macrosolute polarization models were employed to compare performances. Total dissolved solids content above 90 g/L and viscosity above 1.1 x 10(-3) pac s of cell-free culture media were found to decrease average filtration fluxes by over 60% both in the absence and presence of cells. Broth filtration with culture media of dissolved solids levels below 80 g/L were influenced to a greater extent by harvest cell density. The collodial nature of the complex nutrient responsible for the total solids increase affected prediction of filtration performance. Differences in strain filterability were observed with JM109 preferred over DH5 in high solids-containing media and RR1 preferred over JM109 in low dissolved solids-containing media. Their research demonstrates the importance of cell strain and media selection in the performance of early downstream processing steps. (c) 1994 John Wiley & Sons, Inc.