Geochemistry, genesis, and health implications of fluoriferous groundwaters in the upper regions of Ghana   总被引：9，自引：2，他引：9  

W. B. Apambire  D. R. Boyle  F. A. Michel 《Environmental Geology》1997,33(1):13-24

 The most appropriate and widely used source of drinking water for the populations of the upper regions of Ghana is groundwater. In general, groundwater quality is acceptable except for some parts of the Bolgatanga and Bongo Districts, where there are occurrences of elevated levels of natural groundwater fluoride. Concentrations of groundwater fluoride in excess of the World Health Organization (WHO) maximum guideline value (1.5 mg/l) in the Bongo area have been known since 1978. However, the effect of fluoride on people ingesting the water did not receive public and medical attention until October 1993, when health personnel were asked to investigate the cause of stained teeth in school children. The investigation established that 62% of the total population of school children in the Bongo area had dental fluorosis. Against this background, a study was initiated to understand the geochemistry, genesis, and distribution of fluoride in relation to the geology of the area. Groundwater fluoride in the upper regions ranges from 0.11 to 4.60 ppm, with the highest concentrations associated with the fluorine-enriched Bongo coarse-grained hornblende granite and syenite suite. The source of groundwater fluoride within the Bongo granitoids is dissolution of the mineral fluorite and dissolution of and anion exchange with micaceous minerals and their clay products. Applying the WHO recommended guideline values for fluoride in drinking water reveals that 49% of wells in the area deliver water below the optimum level of 0.5 mg/l F^–; these populations are thus prone to dental caries. Twenty-eight percent of the wells fall within the optimum interval for good dental health (0.5–1.5 mg/l F^–). Twenty-three percent of the wells have concentrations above the recommended maximum guideline limit of 1.5 mg/l F^–; this population is susceptible to dental and possibly skeletal fluorosis. Climatic conditions of the area suggest that the individual water consumption is in the order of 3 to 4 l which is higher than the WHO estimate of 2 l/adult/day. In addition, dietary intake for the upper region population is probably higher than WHO baseline values (0.2–0.5 mg/day). This implies that a much higher population is susceptible to developing dental and skeletal fluorosis than originally suspected. Geochemical symbol plot maps help geochemists understand factors controlling the distribution and uptake of fluoride in the upper regions, but they are of minimal value to health officials responsible for planning epidemiological studies and dental health education programs in the region. By casting fluoride data into contoured 'geochemical health-risk maps' using intake interval guidelines more closely aligned to regional climatic and dietary conditions, health officals can better judge the impacts (regional and population based) of fluoride on segments of the population, such as various sex and age groups. Received: 11 March 1997 · Accepted: 17 June 1997  相似文献   

Marine Magnetic Data Processing In Equatorial Regions Off Ghana     

S. K. Buchanan  R. A. Scrutton  R. A. Edwards  R. B. Whitmarsh 《Geophysical Journal International》1996,125(1):123-131

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Spatial and social transformations in a secondary city: the role of mobility in Sekondi-Takoradi,Ghana   总被引：1，自引：1，他引：0  

Paul W. K. Yankson  Katherine V. Gough  James Esson  Ebenezer F. Amankwaa 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(2):82-92

Abstract

Existing research on urban Ghana mainly focuses on processes occurring within the country’s major cities, thereby reproducing a trend within the social sciences to overlook the role of intermediate and secondary cities. This paper aims to address this shortcoming by exploring spatial and social transformations in Sekondi–Takoradi, one of Ghana’s secondary cities and the metropolitan area serving the region’s emerging rubber industries as well as the country’s oil and gas economy. Using qualitative interviews conducted with residents in five of the city’s neighbourhoods, and a modified version of Kaufmann’s typology of mobility, we examine migration into Sekondi–Takoradi, residential mobility within the city and the daily mobility of the city’s residents. The paper highlights how these diverse forms of mobility interact with processes taking place both within and outside Sekondi–Takoradi, most notably influencing and being influenced by livelihood strategies. It is argued that the city and its hinterlands can best be envisaged as a mobile networked whole, rather than consisting of disconnected and compartmentalized locales. The paper thus contributes to broader debates on how mobility shapes urbanization by providing new empirical data on events unfolding in Africa’s secondary cities, and extends existing research by providing a counter-narrative to literature that examines the city and its surrounding rural areas separately.  相似文献   

Understanding usage and preference for health care therapies in a Ghanaian context: A pluralistic perspective     

Prince Michael Amegbor 《Norsk geografisk tidsskrift. Norwegian journal of geography》2017,71(5):288-300

Studies of health care and health-care seeking behaviour in Ghana have mainly shown that many patients tend to use indigenous medicine to address their health care needs. These studies have cited affordability, acceptability, availability, and accessibility as major factors behind the predominant use of indigenous medicine. Nevertheless, in these studies, researchers often ignore the third health care option – self-care, usually subjugated under the indigenous medical system. Since the mid-1980s, both biomedical and indigenous health care systems have witnessed transformations that have shaped and changed their modes of operation, as well as the cost of treatment. In light of this, the author seeks to understand the motivations behind the preference for and use of self-care, professional biomedical care, and indigenous forms of care in the context of Ghana’s health care system. A qualitative, in-depth interview technique was used for data gathering. Findings from the study revealed that time and cost of treatment were major factors accounting for the predominant use of self-care. The author concludes that the findings challenge the long-held belief that biomedicine is not widely accepted by people in Ghana compared with indigenous medicine.  相似文献   

Spessartine Garnets in a Manganiferous Carbonate Formation from Nsuta, Ghana     

Frank K. Nyame  Katsuo Kase  Masahiro Yamamoto 《Resource Geology》1998,48(1):13-22

Abstract: Manganese carbonate ore beds and host rock manganiferous phyllites at the Nsuta mine, western Ghana, contain well developed garnet crystals. Individual crystals are idioblastic, sometimes porphyroblastic, and homogeneous, and are associated with rhodochrosite (with or without kutnahorite), quartz and muscovite. The conspicuous absence of chlorite in garnet-rich assemblages, and of garnet in chlorite-rich rocks, suggest chemical constraints may have been important in the formation of the two minerals. Gondite bands within carbonate ores are interpreted to have resulted from localised processes in which manganese carbonates, in environments rich in alumino-silicate minerals, may have been completely exhausted during metamorphic reactions.  相似文献   

Hydrogeologic and hydrochemical framework of the shallow groundwater system in the southern Voltaian Sedimentary Basin, Ghana   总被引：4，自引：0，他引：4  

Stephen Y. Acheampong  John W. Hess 《Hydrogeology Journal》1998,6(4):527-537

 The southern Voltaian Sedimentary Basin underlies an area of about 5000 km² in east-central Ghana. Groundwater in the basin occurs in fractures in highly consolidated siliciclastic aquifers overlain by a thin unsaturated zone. Aquifer parameters were evaluated from available aquifer-test data on 28 shallow wells in the basin. Hydraulic-conductivity values range from 0.04–3.6 m/d and are about two orders of magnitude greater than the hydraulic conductivity calculated using Darcy's Law and the average groundwater velocity estimated from carbon-14 dating. Linear-regression analysis of the transmissivity and specific-capacity data allowed the establishment of an empirical relationship between log transmissivity and log specific capacity for the underlying aquifers. Groundwater chemistry in the basin is controlled by the weathering of albitic plagioclase feldspar. The weathering rates of various minerals were estimated using ¹⁴C-derived average velocity in the basin. The weathering rate of albite was calculated to be 2.16 μmol L^–1 yr^–1 with the resulting formation of 3.3 μmol L^–1 yr^–1 of kaolinite and 0.047 μmol L^–1 yr^–1 of calcite. The low porosity and permeability of the aquifers in the basin are attributed to the precipitation of secondary minerals on fracture surfaces and interlayer pore spaces. Received, September 1997 Revised, July 1998, August 1998 Accepted, August 1998  相似文献   

Local level impacts of climatic and non‐climatic factors on agriculture and agricultural land‐use dynamic in rural northern Ghana     

《Singapore journal of tropical geography》2018,39(2):178-191

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“Helping” or “Appropriating”? Gender Relations in Shea Nut Production in Northern Ghana   总被引：1，自引：0，他引：1  

Rebecca Kent 《社会与自然资源》2018,31(3):367-381

The potential for the development of shea industries to increase women’s incomes is the focus of a number of development interventions in rural West Africa. However, concerns have been voiced over the potential effects of increased commercialization on women’s rights over this resource. This study examines women’s participation and rights over shea production in a context of increasing commercialization in northern Ghana through a survey of 90 producers and eight oral histories. Although shea incomes are frequently described in the literature as falling under women’s control, joint spending decisions for shea income were reported by half of the married women surveyed. This does not appear to be an outcome of growing assertion of men’s rights over shea trees themselves but rather is explained, by women, largely in relation to their husbands’ involvement in nut production.  相似文献   

A new biostratigraphic correlation for Late Cretaceous–Paleocene strata of the Gulf of Guinea: Evidence from dinoflagellate cysts     

Raquel Sánchez-Pellicer  Edwige Masure  Loïc Villier 《Comptes Rendus Geoscience》2017,349(1):32-41

A new biostratigraphic correlation for Late Cretaceous and Palaeocene strata of the Côte d’Ivoire–Ghana continental margin has been developed from the identification of significant dinoflagellate cyst events in ODP Hole 959D. The Late Cretaceous stage boundaries are mostly consistent with previous studies. However, the Maastrichtian/Danian boundary is placed much lower than previously recognized on the basis of the first occurrences of Carpatella cornuta and Damassadinium californicum. The base of the Selandian is recognized from the last occurrence of Cerodinium diebelii and the first occurrence of Adnatosphaeridium multispinosum. The base of the Thanetian is recognized from the first occurrence of Areoligera gippingensis. The rarity of the age-marker taxa is the main reason for different age determinations among studies of the same section.  相似文献   

Proximity in a Ghanaian savanna: Human reactions to the African palm civet Nandinia binotata     

Michael Campbell 《Singapore journal of tropical geography》2009,30(2):220-231

Understanding human reactions to wildlife, including the differing reactions of different groups to different species, is important given that expanding human population and settlements increasingly result in natural habitat loss or modification and, consequently, wildlife adaptation and encroachment into cleared and created human spaces such as wastelands and farms. This paper examines the importance of gender and age in the responses of rural coastal villagers in Ghana to the presence of African palm civets. Social data gathered from 450 residents in six villages indicated that women and young people were significantly more fearful of civets, seeing them as village marauders, food thieves and livestock predators. Women were also more likely to carry sticks and beat thick vegetation to dispel civets out of concern for the safety of their children and homes. These findings may inform both rural development and conservation debates and policies.  相似文献