Environmental health impacts of East African Rift volcanism

Davies, T.C.

doi:10.1007/s10653-008-9168-7

Cited by 36 publications

(18 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Soils are potentially attractive for animals, with high Ca, Mg, Ca and K contents, but these advantages are offset by other factors. The vegetation growing on these soils often has low Ca and Mg levels, as noted earlier, and geophagia (the practice of eating soil-like substrates) is common today in this part of the Kenya Rift for both humans and animals (Davies, 2008). 'Salt licks' at places where lake beds are (Table S1, Figure S2) contains complete data.…”

Section: Interpretation Of Animal Distributionsmentioning

confidence: 98%

Edaphic and Topographic Constraints on Exploitation of the Central Kenya Rift by Large Mammals and Early Hominins

et al. 2016

View full text Add to dashboard Cite

Our aim in this paper is to create a palaeoenvironmental and spatio-temporal framework for interpreting human land use and exploitation of large mammals in the Central Kenya Rift over the past 2 million years, with particular reference to the Nakuru-Elmenteita-Naivasha basin and its adjacent rift flanks on the Kinangop Plateau and Mau escarpment. We pay particular attention to the tectonic and volcanic history of the region, and to the system of lakes that have undergone periodic expansion and contraction during the Pleistocene in response to climatic and tectonic controls. We use this information to reconstruct topographic features as they would have existed at different periods of the past and their likely influence on patterns of large-mammal movements. In addition we present a systematic mapping of variations in the mineral nutrients of soils -soil edaphics -based on 150 analyses of trace elements in modern soil and vegetation samples. Soil edaphics play an important role in animal and human health today, with serious deficiencies in some areas, and would have exerted an important constraint on animal distributions and movements in the past. We show how soil-edaphic properties vary across the region and demonstrate a close relationship between them and the underlying geology and sediments, which allows us to project patterns back into the past and extrapolate them over larger areas. Using this combination of variables, we construct maps that help to place archaeological sites into their wider regional setting. We focus in particular on the Acheulean site of Kariandusi and show that it occupied a unique window of opportunity in place and time for trapping mammals constrained to move through a narrowly defined topographic bottleneck between edaphically-rich areas. We infer that the site was used for a simple form of ambush hunting and briefly explore the implications for differential site use, formation, preservation and visibility.

show abstract

Section: Interpretation Of Animal Distributionsmentioning

confidence: 98%

Edaphic and Topographic Constraints on Exploitation of the Central Kenya Rift by Large Mammals and Early Hominins

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Fluoride is generally occurring in high concentrations in waters along most of the East African Rift System (e.g. Kilham and Hecky, 1973;Nanyaro et al, 1984;Gaciri and Davies, 1993;Apambire et al, 1997;Nielsen and Dahi, 2002;Reimann et al, 2003;Davies, 2008) and many studies have shown a high prevalence of both dental and skeletal fluorosis in the region (e.g. Shorter et al, 2010;Rango et al, 2012) .…”

Section: Health Hazards Caused By Excess Fluoridementioning

confidence: 99%

Leaching of lava and tephra from the Oldoinyo Lengai volcano (Tanzania): Remobilization of fluorine and other potentially toxic elements into surface waters of the Gregory Rift

Bosshard-Stadlin

Mattsson

Stewart

et al. 2017

Journal of Volcanology and Geothermal Research

View full text Add to dashboard Cite

Volcanic ash leachate studies have been conducted on various volcanoes on Earth, but few have been done on African volcanoes until now. Tephra emissions may affect the environment and the health of people living in this area, and therefore we conducted a first tephra (ash and lapilli sized) leachate study on the Oldoinyo Lengai volcano, situated in northern Tanzania. The recent explosive eruption in 2007-2008 provided us with fresh samples from the first three weeks of the eruption which were used for this study. In addition, we also used a natrocarbonatitic sample from the activity prior to the explosive eruption, as the major activity at Oldoinyo Lengai is natrocarbonatitic. To compare the leaching process affecting the natrocarbonatitic lavas and the tephras from Oldoinyo Lengai, the 2006 natrocarbonatitic lava flow was resampled 5 years after the emplacement and compared to the initial, unaltered composition. Special interest was given to the element fluorine (F), since it is potentially toxic to both humans and animals. A daily intake of fluoride (F-) in drinking water of more than 1.5 mg/l can lead to dental fluorosis, and higher concentrations lead to skeletal fluorosis. For this reason, a guideline value for fluoride in drinking water was set by the WHO (2011) to 1.5 mg/l. However, surface waters and groundwaters in the Gregory Rift have elevated fluoride levels of up to 9.12 mg/l, and as a consequence, an interim guideline value for Tanzania has been set at 8 mg/l. The total concentration of fluorine in the samples from the natrocarbonatitic lava flow is high (3.2 wt.%), whereas we observed a significant decrease of the fluorine concentration (between 1.7 and 0.5 wt.%) in the samples collected three days and three weeks after the onset of the explosive 2007-08 eruption. However, the total amount of water-extractable fluoride is lower in the natrocarbonatitic lavas (319 mg/l) than in the nephelinitic tephra (573-895 mg/l). This is due to the solubility of the different F-bearing minerals. In the natrocarbonatites, fluorine exists predominantly in fluorite (CaF 2), and in the early tephra as neighborite (NaMgF 3) and sellaite (MgF 2). All these three minerals have very low solubility in water (13-16 g/l). The later nephelinitic tephras contain surface coating of villiaumite (NaF), which is highly soluble (42'200 mg/l) in water and can thus release the fluoride more readily upon contact with water. Although there is still the need for further data and a more precise study on this topic in Tanzania, we can already draw a first conclusion that the intake of water during or directly following the deposition of the tephra is not advisable and should be avoided, whereas the release of fluoride from the lava flow has less influence on the river waters.

show abstract

“…Accordingly, most of the cases of environmental health conditions involving dietary fluorine imbalance are reported for populations living within the African rift zones and associated volcanic centres (Davies, 2008). Accordingly, most of the cases of environmental health conditions involving dietary fluorine imbalance are reported for populations living within the African rift zones and associated volcanic centres (Davies, 2008).…”

Section: Fluorinementioning

confidence: 99%

“…Davies, 2008), and these may cause more toxicity problems in humans than dust components from other sources. Davies, 2008), and these may cause more toxicity problems in humans than dust components from other sources.…”

Section: Geogenic Dustmentioning

confidence: 99%

Medical Geology

2010

View full text Add to dashboard Cite

The book series is dedicated to the United Nations International Year of Planet Earth. The aim of the Year is to raise worldwide public and political awareness of the vast (but often under-used) potential of Earth sciences for improving the quality of life and safeguarding the planet. Geoscientific knowledge can save lives and protect property if threatened by natural disasters. Such knowledge is also needed to sustainably satisfy the growing need for Earth's resources by more people. Earths scientists are ready to contribute to a safer, healthier and more prosperous society. IYPE aims to develop a new generation of such experts to find new resources and to develop land more sustainably.

show abstract

Environmental health impacts of East African Rift volcanism

Cited by 36 publications

References 43 publications

Edaphic and Topographic Constraints on Exploitation of the Central Kenya Rift by Large Mammals and Early Hominins

Edaphic and Topographic Constraints on Exploitation of the Central Kenya Rift by Large Mammals and Early Hominins

Leaching of lava and tephra from the Oldoinyo Lengai volcano (Tanzania): Remobilization of fluorine and other potentially toxic elements into surface waters of the Gregory Rift

Medical Geology

Contact Info

Product

Resources

About