Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed
Agricultural intensification in sub-Saharan African countries has significantly increased pesticide applications. Information on pesticide residues and their transport in groundwater and streams is needed to properly manage and reduce any harm to the ecosystem and environment. This information is la...
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MDPI AG
2022-10-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/14/21/3446 |
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| author | Feleke K. Sishu Seifu A. Tilahun Petra Schmitter Getachew Assefa Tammo S. Steenhuis |
| author_facet | Feleke K. Sishu Seifu A. Tilahun Petra Schmitter Getachew Assefa Tammo S. Steenhuis |
| author_sort | Feleke K. Sishu |
| collection | DOAJ |
| description | Agricultural intensification in sub-Saharan African countries has significantly increased pesticide applications. Information on pesticide residues and their transport in groundwater and streams is needed to properly manage and reduce any harm to the ecosystem and environment. This information is lacking in the volcanic soils of Ethiopian highlands. Therefore, this study was conducted to assess pesticide concentrations in ground and surface water and their risk to humans and aquatic life. The 9 km<sup>2</sup> rural watershed Robit Bata in the Lake Tana Basin was selected. Crops were grown under rainfed and irrigated conditions. Pesticide use was assessed, and groundwater samples were collected from eight wells and surface water samples at the outlet twice in the rain phase and once in the dry phase. Samples were analyzed for chlorpyrifos, dimethoate, (α and β) endosulfan, profenofos, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>NO</mi></mrow><mn>3</mn><mo>−</mo></msubsup></mrow></semantics></math></inline-formula>, and pH. Chlorpyrifos and endosulfan, which are strongly adsorbed and slowly degrading pesticides, were found in nearly all surface and groundwater samples, with maximum concentrations in surface water of 8 µg L<sup>−1</sup> for chlorpyrifos and 3 µg L<sup>−1</sup> endosulfan. Maximum groundwater concentrations were only slightly lower. The weakly adsorbed and fast degrading pesticides, dimethoate, and profenofos were detected only in the rain phase after spraying in the groundwater, indicating preferential transport to groundwater at depths of up to 9 m. The average concentration was 0.38 μg L<sup>−1</sup> for dimethoate in surface waters and 1.24 μg L<sup>−1</sup> in groundwater. Profenofos was not detected in surface water. In the groundwater, the average concentration was 0.05 μg L<sup>−1</sup>. Surface water concentrations of chlorpyrifos and endosulfan were highly toxic to fish. The World Health Organization banned these pesticides worldwide. It should be phased out for use in Ethiopia to safeguard the ecological health of Lake Tana, which is rich in biodiversity and endemic fish species. |
| first_indexed | 2024-03-09T18:32:51Z |
| format | Article |
| id | doaj.art-09034a8522174a74bf2c7a5732505170 |
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| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T18:32:51Z |
| publishDate | 2022-10-01 |
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| spelling | doaj.art-09034a8522174a74bf2c7a57325051702023-11-24T07:19:36ZengMDPI AGWater2073-44412022-10-011421344610.3390/w14213446Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ WatershedFeleke K. Sishu0Seifu A. Tilahun1Petra Schmitter2Getachew Assefa3Tammo S. Steenhuis4Faculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, Bahir Dar 6000, EthiopiaFaculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, Bahir Dar 6000, EthiopiaInternational Water Management Institute, Yangon 11081, MyanmarSchool of Architecture, Planning and Landscape, University of Calgary, Calgary, AB T2N 1N4, CanadaFaculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, Bahir Dar 6000, EthiopiaAgricultural intensification in sub-Saharan African countries has significantly increased pesticide applications. Information on pesticide residues and their transport in groundwater and streams is needed to properly manage and reduce any harm to the ecosystem and environment. This information is lacking in the volcanic soils of Ethiopian highlands. Therefore, this study was conducted to assess pesticide concentrations in ground and surface water and their risk to humans and aquatic life. The 9 km<sup>2</sup> rural watershed Robit Bata in the Lake Tana Basin was selected. Crops were grown under rainfed and irrigated conditions. Pesticide use was assessed, and groundwater samples were collected from eight wells and surface water samples at the outlet twice in the rain phase and once in the dry phase. Samples were analyzed for chlorpyrifos, dimethoate, (α and β) endosulfan, profenofos, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>NO</mi></mrow><mn>3</mn><mo>−</mo></msubsup></mrow></semantics></math></inline-formula>, and pH. Chlorpyrifos and endosulfan, which are strongly adsorbed and slowly degrading pesticides, were found in nearly all surface and groundwater samples, with maximum concentrations in surface water of 8 µg L<sup>−1</sup> for chlorpyrifos and 3 µg L<sup>−1</sup> endosulfan. Maximum groundwater concentrations were only slightly lower. The weakly adsorbed and fast degrading pesticides, dimethoate, and profenofos were detected only in the rain phase after spraying in the groundwater, indicating preferential transport to groundwater at depths of up to 9 m. The average concentration was 0.38 μg L<sup>−1</sup> for dimethoate in surface waters and 1.24 μg L<sup>−1</sup> in groundwater. Profenofos was not detected in surface water. In the groundwater, the average concentration was 0.05 μg L<sup>−1</sup>. Surface water concentrations of chlorpyrifos and endosulfan were highly toxic to fish. The World Health Organization banned these pesticides worldwide. It should be phased out for use in Ethiopia to safeguard the ecological health of Lake Tana, which is rich in biodiversity and endemic fish species.https://www.mdpi.com/2073-4441/14/21/3446pesticidegroundwatersurface watereco-toxicityEthiopian highlandssub-Saharan Africa |
| spellingShingle | Feleke K. Sishu Seifu A. Tilahun Petra Schmitter Getachew Assefa Tammo S. Steenhuis Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed Water pesticide groundwater surface water eco-toxicity Ethiopian highlands sub-Saharan Africa |
| title | Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed |
| title_full | Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed |
| title_fullStr | Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed |
| title_full_unstemmed | Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed |
| title_short | Pesticide Contamination of Surface and Groundwater in an Ethiopian Highlands’ Watershed |
| title_sort | pesticide contamination of surface and groundwater in an ethiopian highlands watershed |
| topic | pesticide groundwater surface water eco-toxicity Ethiopian highlands sub-Saharan Africa |
| url | https://www.mdpi.com/2073-4441/14/21/3446 |
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