Browsing by Author "Urban, Brigitte"
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Item A critical review of policies and legislation protecting Tanzanian wetlands(Informa UK Limited, trading as Taylor & Francis Group on behalf of the Ecological Society of China., 2018) Materu, Silvia Francis; Urban, Brigitte; Heise, SusanneIntroduction: The benefit of wetlands for reducing poverty depends on the effectiveness of governance systems that influence peoples’ behaviour in the wise use of wetlands. Objectives: This article critically analyses the current poverty reduction strategies, agrarian policies and economic investments governing wetland usage, especially in Tanzania, with regard to their impact on sustainable Ramsar wetlands management. Methodology: It analyses the management structure, domestic policies and legal framework relating to the protection of wetlands in Tanzania in accordance to the wise use concept of the Ramsar Convention. Outcomes: Tanzanian legal provisions for wetland protection are uncoordinated and too limited in their coverage and scope to sufficiently address the destruction of wetland ecosystems. There is no comprehensive national legal framework to guide sustainable management of Ramsar wetlands in Tanzania as laid out by the Ramsar Convention, which the country ratified in the year 2000. Conclusion: Without a sound legislative and policy-making framework, Tanzanian wetlands and their diverse ecosystem services will continue to degenerate with current strategies of increasing agribusiness and other developmental projects or economic investments. This paper provides critical baseline information to inform decision makers to develop appropriate policy and laws, which promote the wise use of wetlands in Tanzania.Item Seasonal and spatial detection of pesticide residues under various weather conditions of agricultural areas of the Kilombero valley Ramsar Site, Tanzania(Toxicology, Pollution and the Environment, a section of the journal Frontiers in Environmental Science, 2021) Materu, Silvia F.; Heise, Susanne; Urban, BrigitteThis study was conducted in the Kilombero Valley Ramsar Site (KVRS), the largest low-altitude freshwater wetland in East Africa to: 1) determine pesticide contamination of soil, water, and sediment at different seasonal weather conditions 2) critically analyze the seasonal and spatial ecological impacts of pesticide contaminations under tropical weather conditions 3) estimate the potential environmental risks from pesticide exposure based on analytical data. Surface sediments, soil and water samples were collected from sugarcane, teak and rice plantations of the KVRS during the dry (January 2012) and the rainy (March–April 2013) seasons. Samples were screened for 97 different types of pesticide residues using and LC–MS and HPLC–MS. Physical-chemical properties of the sediment and soil samples and meteorological data were analyzed. 92% of soil and sediment samples had relatively low OMcontent (<5%) while 60% of samples had high clay content, indicating high cation exchange capacity that can bind pesticides to the soils. Field soil and air temperature ranging 28–35°C, total sunshine hours-208 h/month, photo radiation −764 MJ/m2, average precipitation 300 mm/month, wind speed >60 km/h, humidity >80% were recorded. Frequency of detection and concentration of pesticides residues depended on seasons. For the dry season sampling, glyphosate/AMPA (0.01–0.55 μg/g), and diuron (0.026–1.7 μg/g) were mostly detected in the sediment and soils. Monuron (1.28–3.9 μg/L) and propoxur (0.05–0.6 μg/L) were mostly detected in the rainy seasons (water and sediments). Glyphosate was above limit of detection in the dry season water samples indicating that its emission into the water system may have been directly through application. Maximum diuron concentrations in water were >30 times higher than the estimated predicted no-effect concentration (PNEC) value (0.054 μg/L) indicating a risk to aquatic community. Calculated porewater concentrations (0.992–0.081 μg/L), exceeded the estimated PNEC values during the dry season, indicating a risk to benthic organisms. Detection of pesticide is influenced by application, environmental factors and the timing of sampling. Further research is recommended to increase our knowledge on soil-water-sediment interactions in the tropics with regard to pesticides.