Paper No. 2
Presentation Time: 8:25 AM
CLIMATE CHANGE AND HUMAN HEALTH RISKS FROM GEOGENIC CHEMICALS IN GROUNDWATERS
POLYA, David A.1, SOVANN, Chansopheaktra
2, SAUER, Johannes
3 and GIBSON, Jonathan
3, (1)School of Earth Atmospheric and Environmental Sciences, University of Manchester, Manchester, M13 9PL, United Kingdom, (2)Department of Environmental Studies, Royal University of Phnom Penh, Russian Federation Boulevard, Toul Kork, Phnom Penh, Cambodia, (3)Department of Economics, University of Manchester, Manchester, M13 9PL, United Kingdom, david.polya@manchester.ac.uk
Human activities have caused significant, measureable secular changes to the trace/minor component composition of two key reservoirs in the biosphere – the atmosphere and soils. Some of these changes are thought by many, though not all, to be major drivers of climate change. Here we explore the consequences of modelled climate change over a 10-100 year timescale on a third major reservoir – groundwaters and the hazardous geogenic chemicals within them. We focus on arsenic, the occurrence of which in well waters has had and is continuing to have devastating human health impacts, particularly in circum-Himalayan Asia. Given the complexity of the interactions between climate & groundwater & groundwater arsenic & attributable human health risks, we focus on qualitatively identifying the nature of these interactions and, through scoping calculations, further identify which ones might usefully be the subject of further study.
On a 10-100 year timescale, climate change impacts groundwater resources either directly, through changes in catchment rainfall, temperature and evapotranspiration, or indirectly, through changes in human behaviour and activities – notably rates of extraction of groundwaters and modifications to the near surface environment.
Secular changes in arsenic hazard in shallow reducing aquifers, widely used for irrigation and other purposes in circum-Himalayan Asia, may plausibly arise from a combination of (i) ingress of labile organic carbon driving arsenic mobilizing biogeochemical processes; (ii) lowering of water tables and (iii) increased magnitude of seasonal changes in water table depths.
Irrespective of such changes in hazard, increased demand for groundwater resources for drinking and irrigation will lead, in the absence of effective mitigation measures, to increased chronic human exposure to arsenic, with concomitant increases in human health impacts.
Acknowledgements. DP acknowledges support through the EU Asia-Link CALIBRE (EC KH/Asia-Link/04 (142966)), AquaTRAIN (EC MRTN-2006-035420)) & PRAMA:(British Council, SA07-09) projects. JG acknowledges an SCI PhD scholarship. The views expressed here do not necessarily reflect those of any of the funders.
