Baseline and Exposure Studies for Persistent Organic Pollutants (POPs) in the Okavango Delta.
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. This information will be gathered in close collaboration with the Chemistry Departments of the University of Botswana and University of Namibia, as well as the Harry Openheimer Okavango research Centre (HOORC), in Maun Botswana, the Department of water Affairs, Conservation International, and other stakeholders in the ORB.
4.Sampling and analysis
In order to establish a baseline contamination levels for the POPs, a sampling program will be conceived to match the properties and anticipated environmental behaviour of the POPs and their derivatives in water, sediment, biota (fish), air and human milk from breast feeding mothers. For more lipophilic compounds the emphasis will be on the sediment phase, while hydrophilic compounds will be sampled from the water column. Depending on the bioaccumulation behaviour, different trophic levels in the food chain will also be sampled. Experience will be shared through joint sampling campaigns for sites that would have been identified through collaboration between ORB stakeholders, particularly the Department of Water Affairs, HOORC, Conservation International, Tsetsefly Control Unit and the Plant Protection Division. The samples will be analyzed at the Chemistry Department at the University of Botswana and for some at the ITM laboratories, in Stockholm. ITM is specialized in the trace analysis of organic contaminants and ancillary parameters in environmental samples.
5. Ecotoxicological assessment
Fish from the Okavango Delta will be collected and analysed for Acetyl-cholinesterase activity. These data will then be compared to fish of the same species, sex and age from a reference area where pesticide impact is low or absent.
6.Human Exposure
As would be expected that human exposure can be through localised use in the household and from the diet, human breast milk will be collected and analysed for breakdown products of POPs with the consent of and in collaboration with the health authorities using appropriate ethical methodologies for involving human subject directly.
7. Risk assessment
The results will be communicated to the relevant authorities in the Delta and Okavango River Basin (ORB) via The Permanent Okavango River Basin Water Commission (OKACOM). A stakeholders workshop/conference will be held in order to integrate the water quality aspect in the integrated management programs working in the ORB. Recommendations will also be made on the changes in land use (chemical release) in the drainage basin that can be tolerated without damaging the ecosystem, and how a monitoring program could be conducted to monitor the impact.
Output
Availability of baseline information on the extent of exposure to POPs and their related breakdown products in the Okavango delta
Stakeholder workshop to share the results of the baseline study and lessons learned
Presentation of findings/results in conferences both local and internbational and pblications in scientific journals.
Locations for project activities
The project activities will take place in Okavango delta panhandle, the delta and peripheral drainage areas including amongst others, Mohembo/Shakawe, Sepopa water swamp, Maun, Lake Ngami, Moremi Game Reserve, Guma and Nxaraga lagoon.
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. This information will be gathered in close collaboration with the Chemistry Departments of the University of Botswana and University of Namibia, as well as the Harry Openheimer Okavango research Centre (HOORC), in Maun Botswana, the Department of water Affairs, Conservation International, and other stakeholders in the ORB.
4.Sampling and analysis
In order to establish a baseline contamination levels for the POPs, a sampling program will be conceived to match the properties and anticipated environmental behaviour of the POPs and their derivatives in water, sediment, biota (fish), air and human milk from breast feeding mothers. For more lipophilic compounds the emphasis will be on the sediment phase, while hydrophilic compounds will be sampled from the water column. Depending on the bioaccumulation behaviour, different trophic levels in the food chain will also be sampled. Experience will be shared through joint sampling campaigns for sites that would have been identified through collaboration between ORB stakeholders, particularly the Department of Water Affairs, HOORC, Conservation International, Tsetsefly Control Unit and the Plant Protection Division. The samples will be analyzed at the Chemistry Department at the University of Botswana and for some at the ITM laboratories, in Stockholm. ITM is specialized in the trace analysis of organic contaminants and ancillary parameters in environmental samples.
5. Ecotoxicological assessment
Fish from the Okavango Delta will be collected and analysed for Acetyl-cholinesterase activity. These data will then be compared to fish of the same species, sex and age from a reference area where pesticide impact is low or absent.
6.Human Exposure
As would be expected that human exposure can be through localised use in the household and from the diet, human breast milk will be collected and analysed for breakdown products of POPs with the consent of and in collaboration with the health authorities using appropriate ethical methodologies for involving human subject directly.
7. Risk assessment
The results will be communicated to the relevant authorities in the Delta and Okavango River Basin (ORB) via The Permanent Okavango River Basin Water Commission (OKACOM). A stakeholders workshop/conference will be held in order to integrate the water quality aspect in the integrated management programs working in the ORB. Recommendations will also be made on the changes in land use (chemical release) in the drainage basin that can be tolerated without damaging the ecosystem, and how a monitoring program could be conducted to monitor the impact.
Output
Availability of baseline information on the extent of exposure to POPs and their related breakdown products in the Okavango delta
Stakeholder workshop to share the results of the baseline study and lessons learned
Presentation of findings/results in conferences both local and internbational and pblications in scientific journals.
Locations for project activities
The project activities will take place in Okavango delta panhandle, the delta and peripheral drainage areas including amongst others, Mohembo/Shakawe, Sepopa water swamp, Maun, Lake Ngami, Moremi Game Reserve, Guma and Nxaraga lagoon.
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Project Snapshot
Grantee:
University of Botswana, Department of Chemistry
Country:
Botswana
Area Of Work:
Chemicals
Grant Amount:
US$ 50,000.00
Co-Financing Cash:
US$ 59,259.26
Co-Financing in-Kind:
US$ 30,000.00
Project Number:
BOT/98/G52/05/04
Status:
Satisfactorily Completed
Project Characteristics and Results
Planning gef grant
? A proposal was submitted to SGP-GEF to request funding for a second phase to the project that would attempt to address issues arising from the present work. The presence of pesticides in the water and sediments implied their presence at much higher levels in fish hence a second phase that would address fish and monitor levels in water and sediments simultaneously.
Project sustainability
? Currently proposals have been and are being submitted to other funding organizations to enable further monitoring of pollutants in the Delta. A second phase of the project has commenced with aims to assess contamination levels and effects in biota as well as to estimate human exposure to the contaminants.
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SGP Country office contact
Mr Baboloki Autlwetse
Phone:
002673633768
Email:
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Gaborone, SADC
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