The Cameroon Academy of Sciences model of evidence-based science advice

The evidence-based science advice (ESA) effort of the Cameroon Academy of Sciences (CAS) since 23 years has been reviewed. The objective throughout has been to enable science influence policy/decision making at all levels – national, regional and global. The key partners of CAS included the United States National Academy of Sciences (USNAS), the German Academy of Sciences (Leopoldina), the Royal Society of United Kingdom, as well as the Network of African Science Academies (NASAC), the InterAcademy Partnership (Science, Health, Research), the Commonwealth Science Academies and the International Science Council. The mechanisms used included consensus studies, workshops, public lectures, participation in sectoral committees, summaries of key scientific publications and joint statements. Priorities handled through convening activities were triggered by policy/decision making sector requests or Academy foresights. The response/impact of the effort varied from media coverage through policy/programme change/orientation. The major challenges faced included insufficient financial/human resources, inadequate office space, and weak links with government. These challenges must be addressed to enable effective evidence-based science advice which is increasingly unavoidable for sustainable development.Keywords: Evidence-based science, advice, policy, decision-make

Physico-chemical, Mineralogical And Chemical Considerations In Understanding The 2001 mabeta New Layout Landslide, Cameroon

Landslides are part of natural catastrophic disasters destroying both biological and physical entities including loss of human lives. An evaluation of soil properties involved in landslides is significant in its management. To this effect, soil samples from the 2001 landslide occurrences in the Mabeta New Layout, Limbe, Cameroon were analysed using standard techniques to determine texture, pH, electrical conductivity (EC), bulk density (Db), water absorption percent (WA), linear shrinkage, plasticity index (PI), loss-on-ignition (LOI), mineral content and major cations. Results obtained were: bulk density (0.89 \u2013 1.08 g/cm3), LOI (19.4 - 25.7%), water absorption (23.4 \u2013 29.1%), linear shrinkage (5.4 \u2013 8.3%), volume shrinkage (4.8 \u2013 8.5%), PI (13.5 \u2013 20.75%), major cations ((Fe2O3 : 9.91 \u2013 23.24%), (Al2O3 : 9.88 \u2013 28.48%), (CaO : 0.73 \u2013 1.3%), (MgO : 0.55 \u2013 2.80%), (K2O : 1.06 \u2013 1.59%), (Na2O : 0.77 \u2013 0.89%)), pH (5.17 \u2013 6.90) and EC (16.53 \u2013 149.20\u3bcS/cm). Values from physico-chemical analyses, secondary minerals abundance index (SMAI) and chemical index of alteration (CIA) of the soils were reflective of particles with high potential for sliding. With major contributions from favourable slope, seismic and hydrologic forces, the event occurred

Defluoridation of fluoride-rich groundwater in Mayo Tsanaga River Basin-Cameroon using locally produced bone char

With fluoride-rich groundwater causing a climatic-dependent fluorosis in Mayo-Tsanaga River Basin, the overall objective of this study was to reduce fluoride concentrations in drinking water to acceptable levels thereby improving the resilience of the population to this climate change induced pathology. The specific objectives were to: (1) assess water chemistry in the study area to re-affirm the undesirable fluoride levels; (2) assess the impact of seasons on the concentrations of fluoride; (3) construct and evaluate the performance of a household bone char-based adsorption defluoridation filter. A combination of hydrogeochemical and engineering analyses demonstrated that the groundwater is predominantly Ca+Mg-HCO3 type, which contains as much as 6.73 mg/l of undesirable concentrations of geogenic fluoride. These concentrations increased with elevated pH, electrical conductivity and in the dry season, and were reduced to less than 0.2 mg/l when the groundwater was subjected to filtration through 300 g of 0.2-0.8 mm faction of charred cow bones in a home-based defluoridation filter. The bone char in the filter can effectively reduce fluoride concentration to less than 0.7 mg/l, which is the local threshold limit, without negative impact on the organoleptic (taste, color and odor) characteristics of drinking water. Compared with the commercially activated carbon, the bone char has an additional capacity of adsorbing fluoride at a rate of 4 mg/liter in 30 minutes, which indicates that with a defined saturation time, the bone char filter can protect the population against climate change-induced fluoride enrichment in drinking water.Keywords: Groundwater. geogenic fluoride. climate dependent fluorosis. bone char defluoridation. water chemistr

Defluoridation of fluoride-rich groundwater in Mayo Tsanaga River Basin-Cameroon using locally produced bone char

With fluoride-rich groundwater causing a climatic-dependent fluorosis in Mayo-Tsanaga River Basin, the overall objective of this study was to reduce fluoride concentrations in drinking water to acceptable levels thereby improving the resilience of the population to this climate change induced pathology. The specific objectives were to: (1) assess water chemistry in the study area to re-affirm the undesirable fluoride levels; (2) assess the impact of seasons on the concentrations of fluoride; (3) construct and evaluate the performance of a household bone char-based adsorption defluoridation filter. A combination of hydrogeochemical and engineering analyses demonstrated that the groundwater is predominantly Ca+Mg-HCO3 type, which contains as much as 6.73 mg/l of undesirable concentrations of geogenic fluoride. These concentrations increased with elevated pH, electrical conductivity and in the dry season, and were reduced to less than 0.2 mg/l when the groundwater was subjected to filtration through 300 g of 0.2-0.8 mm faction of charred cow bones in a home-based defluoridation filter. The bone char in the filter can effectively reduce fluoride concentration to less than 0.7 mg/l, which is the local threshold limit, without negative impact on the organoleptic (taste, color and odor) characteristics of drinking water. Compared with the commercially activated carbon, the bone char has an additional capacity of adsorbing fluoride at a rate of 4 mg/liter in 30 minutes, which indicates that with a defined saturation time, the bone char filter can protect the population against climate change-induced fluoride enrichment in drinking water

Physico-chemical, Mineralogical And Chemical Considerations In Understanding The 2001 mabeta New Layout Landslide, Cameroon

Landslides are part of natural catastrophic disasters destroying both biological and physical entities including loss of human lives. An evaluation of soil properties involved in landslides is significant in its management. To this effect, soil samples from the 2001 landslide occurrences in the Mabeta New Layout, Limbe, Cameroon were analysed using standard techniques to determine texture, pH, electrical conductivity (EC), bulk density (Db), water absorption percent (WA), linear shrinkage, plasticity index (PI), loss-on-ignition (LOI), mineral content and major cations. Results obtained were: bulk density (0.89 – 1.08 g/cm3), LOI (19.4 - 25.7%), water absorption (23.4 – 29.1%), linear shrinkage (5.4 – 8.3%), volume shrinkage (4.8 – 8.5%), PI (13.5 – 20.75%), major cations ((Fe2O3 : 9.91 – 23.24%), (Al2O3 : 9.88 – 28.48%), (CaO : 0.73 – 1.3%), (MgO : 0.55 – 2.80%), (K2O : 1.06 – 1.59%), (Na2O : 0.77 – 0.89%)), pH (5.17 – 6.90) and EC (16.53 – 149.20μS/cm). Values from physico-chemical analyses, secondary minerals abundance index (SMAI) and chemical index of alteration (CIA) of the soils were reflective of particles with high potential for sliding. With major contributions from favourable slope, seismic and hydrologic forces, the event occurred

Forensic assessment of the 1999 Mount Cameroon eruption, West-Central Africa

The 28 March to 22 April 1999 eruption of Mount Cameroon volcano in southwest Cameroon occurred from multiple vents along fissures at two sites. Vents opened first at the upper site 1 (2650 m) and were more explosive than vents at the lower site 2 (1500 m), which were more effusive. Earthquakes, lava flows, tephra fall, ballistics and gas emissions affected the volcano's west and south flanks, including forests, plantations, stock animals, water supplies, coastal communities and their people. Through an analysis of existing published data and new interview data, we provide an overview of the environmental, social and economic consequences of these hazards on infrastructure, human health, and socio-economic and agricultural activities of the four coastal communities most affected by the eruption: Batoke, Bakingili, Debundscha and Idenau. The collected data provide a more detailed description of the short- and long-term direct and indirect effects of the eruption and response than has been provided to date. Sedimentation of tephra and ballistics from site 1 produced both short-term and long-lasting impacts on people, through the contamination of plants and water supplies, which induced impacts on human health and commercial activities. A ~9.2 km long lava flow erupted from site 2 received significant short-term attention as it severed the only arterial coastal highway, forced the evacuation of some 600 residents of Bakingili, and interrupted commerce between communities. The agricultural sector also suffered due to burning of crops and soils. The only obvious significant benefit of the eruption appears to be that the long lava flow has become a tourist attraction, responsible for bringing in money for food, drink and lodging. However, the long-term cascading effects caused by the hazards have proven to be more severe than the immediate direct and indirect effects during the eruption

Increased risk of fluorosis and methemoglobinemia diseases from climate change: evidence from groundwater quality in Mayo Tsanaga River Basin, Cameroon

Current assessments of the impacts of climate variability and change on water resources commonly exclude groundwater. Thus, the identification of actual and potential health threatening elements in the groundwater, and linking up to climate variation and change at hydrologic catchment scale is an important ingredient for identifying feasible local-scaled adaptation strategies. Against these backdrops the focus of this paper was to assess the implications of climate change on groundwater-derived methemoglobinemia, and fluorosis which have been identified in Mayo Tsanaga River Basin (MTRB), North Cameroon. The basic approach of the study involved collection and analyses of previously published reports and articles that are related to the impact of climate change on water resources in Cameroon. Moreover in addition to groundwater samples that were collected from hand dug wells and boreholes in the dry season, streams, rivers, springs, and dams were sampled in the rainy season. In-situ measurements, and determination of electrical conductivity, pH, water temperature, atmospheric temperature, and alkalinity, respectively, were done. Laboratory analysis of potassium, sodium, calcium, magnesium, chloride, sulfate, nitrate, and fluoride was done by ion chromatography. The succinct results showed that atmospheric averaged annual temperature has increased from 28ºC to 29ºC over the past 40 years. Projected temperature for the year 2030 is 30ºC. Twenty seven percent of the sampled drinking water sources were contaminated by fluoride, which is causing fluorosis. The variation in nitrate suggests that during the dry season water in rivers, springs, dams, boreholes, and shallow wells contained nitrate below the WHO upper limit of 45 mg/l, while in the rainy season some shallow wells were polluted by nitrate. In contrast to the relationship of fluoride with groundwater age and depth, nitrate concentrations increased with decreasing age and depth of the groundwater. Based on the premises that a complex nexus exists between climate change, groundwater quality and health in the study area, adaptation and mitigation strategies were identified, and summarized with the accronym “ADAPT” for: Avoid untreated groundwater from deeper aquifers, Drink water from rain, rivers, and springs, Adopt local drinking water norms, Prohibit shallow well water in the rainy season and Treat young groundwater for nitrate and old groundwater for fluoride before drinking.Keywords: Climate change, Groundwater quality, Fluorosis, Methemoglobinemia, Adaptation strategies, Mayo Tsanaga River BasinJOURNAL OF THE CAMEROON ACADEMY OF SCIENCES Vol. 11 No. 1 (2013