SHEATHE: Xenobiotic substances and heavy metals in the environment – a threat to health, ecosystems and development in Ghana

Research Programme

 

There are four major research sub-themes. WP 1 and 2 provide knowledge on status and trends in sources, dispersal and possible effects of heavy metals and xenobiotic substances on local and wider geographic (country) scale. WP 3 investigates the effect of access to information in risk handling for individuals and at the community level. WP 4 deals with data collection for heavy metals and xenobiotic substances (measurements and chemical analysis).

 

WP 1: Large scale assessment of pollution patterns and trends

 

Data analysis will be made both with classical (geo) statistical methods and with the use of models. Data on soils, population density, landcover/land use and climate will be included in the analysis. There is a lack of activity data, especially for activities in the informal sectors, but e.g. gold mining activities will be confined to specific soil types.

 

Large scale dispersal and trends in concentrations will be modeled with the EMEP MSC-E GLE- MOS model for air and the SWAT model (Soil and Water Assessment Tool) for water. For soils, the IDMM model will be used for metals and the Gleams model for POP’s. The EMEP MSC-E GLEMOS model is an open source modular multi-scale (global to local), multi- pollutant simulation platform. The SWAT model is a widely applied eco-hydrological model. Model parameterization will be guided by literature survey, databases on physicochemical properties of sub- stances, and QSAR estimates using the QSARINS package.

 

WP 2: Local scale assessment of pollution patterns and trends

 

More intensive studies of local scale variability in concentrations, emissions, dispersal and deposition (including dust) will be undertaken in smaller catchment areas with known pollution sources, and will include local knowledge. The models described earlier will be used in local scale versions together with local compartment and contamination route models developed in the project to describe, e.g. the relation between concentration levels, bioavailability and human intake.

Three ASM sites and two WEEE recycling sites will be selected for study of local emission and dispersal patterns. One of the local ASM areas will be selected for analysis of transfer routes via organic waste and compost, and for study of crop concentrations. The result from this work package will be used to describe local-scale variability linking to WP 1 and form input for the participatory risk assessment activity in WP 3. Results from earlier studies at local scale in Ghana will be included in assessments; however, these are only fragmentary and may be outdated due to rapid increase in emission rates.

 

WP 3: Community based risk assessment

 

In three local ASM areas / communities, and two WEEE areas / communities, the effect of access to information in developing risk handling strategies will be scientifically investigated. This study will be conducted in areas also selected for study of local scale pollution (WP 2) in cooperation with the local community. The use of information in risk assessment and risk handling both on individual and community level will be investigated through structured interviews, focus group discussion and direct observation before and during the project. Both random methods and the snowball method will be used for selection of informants in order to gain information about the general knowledge level, on one hand, and to get contact to the most knowledgeable individuals (key informant interviews), on the other hand. Because of the transient nature of some ASM communities, the study in each area will be focused in a ten month period. The longer term effects will be studied with a follow up two years after. The project will focus on the poor, who are likely to be most exposed to pollution from air and water, and whose access to (safe) food relies on informal markets. Gender differences will be elucidated throughout the study. Women play a major role in food supply and small-scale farming.

 

WP 4: Data collection, measurements and chemical analysis

 

Data collection campaigns will use the same equipment and analytical procedures at both the local and national scale. The equipment includes a real-time mercury analyser, a high volume active air sampler with filters for particles, xenobiotic substances and heavy metals, and passive air samplers (PUF for xenobiotics, PIMS for Hg). A research drone carrying the L analyser will be used for the measurement of transects of Hg concentrations in air. For the collection of soil, water and sediment samples, simple, low cost equipment will be used while ensuring sample suitability for trace analysis.

In addition to the regular (background) sampling in the local scale study areas, soil, water and sediment samples will be collected and analysed for Hg in order to identify mining and environmental hotspots.

Data collected will be used for analysis of particles, heavy metals, and for inter-calibration. In four main rivers (Tano, Ankobra, Pra, and the Black Volta), which integrate runoff from the main mining areas, water and sediment samples will be taken and water flow measured monthly in a one year period at ten stations in each river. Samples from the Volta River and Lake will be included for analysis of background levels.