Chemicals

Background The project area comprises mainly the Okavango River Basin catchment area in Botswana. The Okavango River Basin (ORB) is shared by three Southern Africa nations- Angola, Botswana, and Namibia. The Okavango wetland is one of the world s largest inland Deltas and still has near pristine aquatic ecosystem. The extraordinarily rich biodiversity and scenic beauty of the Delta and its component ecosystems have made it a major international tourist attraction with widespread national and international concern about the future of the unique system. The government of Botswana s listing of the Okavango Delta (including a wide area of peripheral drainage and associated terrestrial ecosystems) as a Ramsar site in 1996 accorded the system the status of a wetland of international importance . The Okavango Delta is actually a low gradient alluvial fan where the Okavango River discharges into a collapsed section of the earth s crust related to the East African Rift Valley system. The Cubango and Quito Rivers combine to form the Okavango River which enters Botswana confined in a narrow depression known as the panhandle. Base flow in the Okavango River sustains about 3000 km2 of permanent swamp in the Panhandle and around the apex of the alluvial fan, but the area of inundation shows great seasonally and inter-seasonal variability, between about 2500 and 12,000 km2. Rainfall in the catchment in the Angolan highlands falls from December to March. Because of the very low topographic gradient, movement of the flood wave across the fan takes four to five months to traverse the 250 km from Mohembo at the apex of the panhandle to Maun at the southern end of the Delta. It supports a key component of Botswana`s growing tourist industry and sustains thousands of rural inhabitants. The Okavango Delta contributes to the livelihood of the communities through provision of fish, the main protein source, other food sources, the much needed income and employment from craft production and the tourism industry. The main threats to the water quality and ecosystem of the Okavango River Basin arise from establishment fo commercial agricultural activities along Okavango River floodplain and oil spillages from the tourism industry. Persistent organic pollutants such as DDT and endosulfan have been employed for several years in the Okavango delta for tsetse fly (Glossina morsitans centralis) control in the quest to fight against malaria. In the recent years, aerial spraying has been done using the less persistent pesticides such as deltamethrin due to amounting pressure on the use of environmental friendly pesticides. The challenge presented by the continued use of POPs in the Okavango Delta means that there are bound to increase in concentration particularly in the water, sediments, biota and eventually in the food chain. There is no available data as to how much of the POPs used this far have accumulated in the environment as well as in the food chain. Because fish is a major source of protein for the habitants living around the Okavango Delta and also for the tourism industry, it is essential to carry out a baseline analysis in order to acquire such data. Baseline data has an important role as it can always be used in the future to see if there is an increase in exposure to POPs. Therefore these results will impact directly on the fishing communities as well as the consumers at all levels. Through consultation with the Ministry of Health, the Department of Health in the Northern District, procedures in-line with approved ethical methodologies will be adapted for the analysis of breast milk. Breast milk is viewed as a good indicator of the distribution of POPs in the food chain. Objectives 1)To provide the first baseline data on pesticide contaminant levels in the Delta, in order to characterise the Delta`s current ecological and chemical status and to identify any future deterioration or improvements in its water quality. 2)To use the information to ascertain the response of the Delta`s water quality to increased human activity both upstream and in the Delta itself. 3) To gather data on patterns and trends in contaminant concentrations and distributions and their effects on selected parts of the Delta ecosystem so as to describe their general sources, pathways, and loadings to the Delta. 4)To strengthen Botswana`s institutional capacity in research and analysis of environmental anthropogenic contaminants. 5)To establish contaminant levels in human milk as well as the fish that constitutes the dietary requirements of the population. Activities 1. Scenario development Literature review amd consultation with all stakeholders in the Okavango River Basin resulting in a clearly defined flow season of the Okavango River, a series of possible/probable scenarios for the use of POPs within the Okavango watershed in the past as well as upcoming years. 2. Establishment of collaborations and partnerships Linkages and collaboration established with NGOs, communities, various government departments and North West District Council for networking, participation and contribution in issues concerning POPs. 3. Model development A detailed knowledge of the local environment, a water mass balance and a particulate organic carbon mass balance for the aquatic environment are required, in addition to climatic information and details on soil properties, vegetation coverage as well as a good understanding of the local ecology will also be essential. T

Botswana