afrirpa 2010, sources, processes and fate of environmental radioactivity
DESCRIPTION
Invited plenary talk given by Prof. Farid El-Daoushy at Inter. Radiation Protection Congress, Afrirpa-2010, Sept. 2010, Nairobi, Kenya.This talk summarizes the sources, processes and fate of environmental radioactivity (natural and artificial) at the earth\'s surface. It links environmental radioactivity to radiation and environmental protection issues in Africa. The role of global and regional processes on the transport and accumulation of anthropogenic waste in complex ecosystems, e.g. the Nile Basin, are described. These issues help fulfilling the African mission and vision for achieving their golals: ONE PEOPLE, ONE GOAL, ONE FAITH.TRANSCRIPT
Sources and fate of environmental radioactivity at the earth’s surface
Farid El-Daoushy, Department of Physics and Astronomy, Uppsala University, Sweden
Objectives: To link environmental radioactivity to RP in Africa? To describe the benefits of Africa from this field in terms of RP, safety and security policies. To create a mission and a vision to fulfil the needs of ONE PEOPLE, ONE GOAL, ONE FAITH.
Sources, processes and fate of environmental radioactivity
(1) Factors influencing cosmogenic radionuclides
(2) Factors influencing artificial radionuclides: (a) nuclear weapon-tests
(b) nuclear accidents (c) Energy, mining and industrial waste
(3) Factors influencing the global Rn-222 and its daughters.
(4) Dynamics of cycles of natural radioactivity, e.g. Pb-210.
(5) Environmental radiotracers act as ”DIAGNOSTIC TOOLS” to assess air and water quality and impacts of the atmospheric and hydrospheric compartments on ecosystems.
(6) Definition of base-lines for rehabilitation and protection
Previous experience helps setting up an African agenda
Sources, processes and fate of environmental radioactivity
Nuclear Weapons Tests
Sources
Sinks
Transport
Chemistry
Cosmogenic Radio-isotopes
Human Activities
BiogenicActivity
UndergroundProcesses
VolcanicEruption
Tracers
Polar Ice Ocean Sediments
Corals Deltas& Soils
Lake Deposits Plants Ground
Water Peats Glacier LoessDeposit
Cs-137, Sr-90 C-14, Pu-238, .
Be-7, Be-10, C-14, I-129
Pb, Hg, soot,CO2, CH4, NOx,
S-, N-, P-comp., CO2, CH4, ..
U/Th, Ra-226, Rn-222, Pb-210
Dust, CO2
Radio-activity to trace natural and human impacts
stratosphric-tropospheric exchange
water cycle
interhemispheric mixing
assimilation
dispersionevaporationmelting
precipitationatmospheric circulation
ocean circulation
air-seaexchange
fractionation
Rn-222 Pb-210 +
Ra-226 U-238 Pb-210
Be-7, C-14, Be-10
Premordial nuclides Cosmogenic nuclides
Rn-222
Natural radionuclides are elegant atmospheric tracers
What is our knowledge on such tracers in African eco-system?
U-238 and the global production of radon
small-scale emanation large-scale exhalation
Do we have an African map on the production and atmospheric behaviour of Rn-222 and daughters
Pu-238, Pu-239, Pu-240, Cs-137, Sr-90,..
Artificial radionuclides from atomic bomb tests
Knowledge on behaviour and fate of these nuclides in African ecosystems is needed through collaborative research with Africans. Safety and security requires preparedness.
Short-term transport/deposition of Chernobyl Cs-137 through tropospheric and boundary-layer processes
Global aerosol emissions: C, CO2, SO2, NO2, Pb
Climate influences sources/behaviour/fate of environmental radioactivity. Impacts on life forms in Africa would be severe. Assessing environmental radioactivity resolves these issues.
Global trajectories of air masses
Africa is a continent with symmetrical land around the equator, latitudes 30⁰ south and 30⁰ north
Rn-222, Pb-210
Be-7, Be-10
Aerosol dynamics: formation, growth, attachment (sources transport/chemistry deposition)
Understanding dry-wet removal pattern of environmental radioactivity in the atmospheric compartment of the Nile Basin is important for both fundamental and applied research needs.
Large-scale and long-term transport and chemistry processes bring soluble, particulate and collides to surface water bodies
Coupled evaporation-precipitation and surface-ground water interaction have new climate/human impacts in the Nile Basin
Cloud formation Water fall Mountain lakes
Agricultural/forest landInland lakes
Studies of cloud, rain and surface-water processes in Europe
Interactions in water bodies, e.g. lakes and rivers,depend on the involved sub-compartments
Natural analogues for nuclear waste studies
NORM-industries and deep geological depositories impose new threats for coupled surface-ground water Interactions
Behaviour of U-series nuclides in glacial deposits above the bedrock
The Nile Basin involves complex interactions with
several spatio-temporal scales.
Studies of climate and environment
impacts need coordination of a
wide-range of facilities/resources.
Studies of Complex river systems in AfricaBehaviour of radioactivity in these ecosystems has coupled environment-climate dimensions.
Eco-system dynamics in regional/global scales
Up-scaling from small-scale to large-scale
Threats from humans, energy and industry
Coupled effetcs from environment and climate
Major issues to consider in these studies:
Comprehensive Test Ban Treaty ”CTBT”: global watching gamma spectrometers
”CTBT” global watch can be extended with African units to build multi-tracer databases:
- to follow environmental radioactivity in Africa
- to develop, validate and test models in Africa
- to support climate impact studies for sustainability of African natural resources.
Conclusions
Thanks for your attention.
Understanding radioactivity in Africa has basic/applied input:
- Filling huge data-gaps in global environmental radioactivity- Filling huge gaps on the behaviour of radioactivity in Africa- Assessing climate-environment impacts in complex rivers- Assessing global cycle of Sahara dust & impacts on climate- Assessing climate-environment impacts on natural self-cleaning
- Understanding major impacts of climate in Africa on: sustainability of environment and ecosystems, e.g. erosion of fertile land, salination of freshwater, changes in evaporation-precipitation, dry-wet periods and spatio-temporal dynamics of flooding, coupled ground-surface water interactions, impacts of mining, industry and land-use on air and water quality as well as quality of food-chain and biodiversity.