Introduction: Radioactivity and Our Well-Being 27 is carried out with gamma rays, x-rays, and fast neutrons, in addition to chemical mutagens. As reported in the IAEA Nuclear Technology Review (2006) other nuclear techniques used are the radioisotope labeling of nucleic acids used as probes for genetic fingerprinting, map- ping and marker-assisted selection, and mutagenesis for the analysis of gene function. The Joint FAO/IAEA Division in Vienna, Austria carries out extensive coordinated research programs with member states utilizing nuclear and conventional techniques in mutation plant breeding. The induced mutations created by nuclear radiation and chemicals have led to major advances in plant breeding for crop improvement. The beneficial mutants have been selected and used by plant breeders for over 50 years. The Nuclear Technology Review (2006) reports that, to date, approximately 2500 officially registered mutant varieties of more than 160 plant species worldwide are listed in the FAO/IAEA Mutant Variety Database. An example cited is a mutant rice cultivar with high quality and tolerance to salinity, which has been released in Vietnam. It is one of the top five export rice varieties, which occupies 280,000 ha of the export rice area of the Mekong Delta. The target area for the salt tolerant rice cultivar for Bangladesh, India, Philippines, and Vietnam encompass an estimated area of 4.3 million ha. The IAEA Nuclear Technology Review (2005) reports that mutation induction coupled to selection remains the most "clean" and inexpensive way to create varieties by changing single characteristics without touching the general phenotype. Major successes are reported for mutagenesis-enhanced breeding in the USA (rice, barley, sunflower, grapefruit, pep- permint), Pakistan (cotton), India (blackgram), Australia and Canada (linseed), Japan (pear), and China and Australia (rice). Mutant varieties of oil seeds and pulses are being released for commercial cultivation. Other changes created through induced mutation with nuclear radiation and chemicals are disease and pest resistance and crop nutritional and processing quality. There are an increasing number of private enterprises involved in research in mutation- induction breeding for ornamental flowers as well as industrial and food crops. 4 WATER RESOURCES Water, like the air we breathe, is a valuable and vital resource. It is in great demand for domestic use, agricultural irrigation, and industrial productivity. Many people in many nations do not have adequate water supplies, and scientific research into maintaining and improving the supply and quality of our water is vital to human development and the con- servation of the environment. In an address given at the Opening Ceremony of the Environment Exhibition on the Occasion of the 50th General Conference of the International Atomic Energy Agency (IAEA) on September 19, 2006, in Vienna, Austria, Professor Dr Werner Burkart stated the following concerning global water resources and the role of nuclear technology in helping the world meet its future water needs: Here in Vienna, there is an abundance of good quality water, sometimes too much pouring from the skies, but more than 1 billion people [worldwide] have no access to clean water, and predictions are that, without intervention, about two-third's of the world's population will face shortages by 2025. It is a goal of the World Summit on Sustainable Development to halve the number of people without access to clean water by the year 2015. Nuclear technology is part of that effort. By using naturally 28 Introduction: Radioactivity and Our Well-Being occurring isotopes, we can trace the origin and movement of water and specific pollutants .... This information is difficult to obtain by other means, but is critical for developing robust and affordable policies for the protection of freshwater resources. Also, in his opening statement at the International Symposium on Isotope Hydrology and Integrated Water Resources Management (IAEA, 2004a) held in Vienna during May 19-23, 2003, Professor Burkart added As many of us here are aware, the global demands for freshwater have been increasing much faster than the ability of many nations to meet these demands .... Currently, surface waters in rivers and lakes are being exploited to the maximum, and ground water resources are getting depleted or contaminated in many parts of the world. Extensive hydrological information is necessary to sustain the current and future levels of human development, to protect available water resources from pollution and over exploitation .... Isotope techniques help to provide rapidly hydrological information for large areas and will undoubtedly be a key component of global efforts in water resource assessment and management. By tracing the changes in the isotopic composition of our water resources including iso- topes of hydrogen (]H, 2H, and 3H), oxygen (160, 170, and 180), carbon (lec, 13C, and 14C), nitrogen (14N and lSN), and others, isotope hydrologists can obtain valuable data on hydro- logical dynamics that could otherwise be impossible or immensely difficult to obtain. Isotopes are used to measure the processes illustrated in Figure 8 of the hydrologic cycle in TranspiraUe \\\\\\ \ \\ \\ \\ \ \ \\ \ Throughfa Precipitation 8troamflow ¢ Flow Figure 8 Catchment hydrologic processes composing a local hydrologic cycle. Each of these processes can be assessed by lithogenic and cosmogenic nuclides. (From Nimz (1998), reprinted with permission from Elsevier © 1998.) Introduction: Radioactivity and Our Well-Being 29 catchment, including, the groundwater origins, the dating and renewal rate of groundwater, and sources of pollution or contaminant intrusions into groundwater, etc. A thorough review of the isotope tracer techniques used in studies of catchment hydrology is provided in the book edited by Kendall and McDonnel (1998). A comprehensive review by Nimz (1998) cites numerous isotopes as tools for measuring the dynamics of catchment hydrolic processes such as variations in 87Sr natural abundance, or ~ 87Sr, which will vary in waters depending on the water origin (e.g., bedrock, soil leachate, rain, etc.) in the catch- ment. Precise measurements of variations in isotope natural abundances are made with a mass spectrometric analysis. Another isotopic technique involves the measurement of 36C1/C1, that is, the ratio of the isotope 36C1 to the total chlorine in a sample, because the atmospheric input of 36C1 to the chlorine content of water can be used as a groundwater tracer (Caffee et al., 1992; Nimz et al., 1993, 1997; Nimz, 1998). The thermonuclear atmospheric weapons tests during the 1950s and 1960s enriched the atmosphere with 36C1, which has a half-life of 3 × 105 years. Water older than 1950 (>50 years), which is water that has not mixed with water exposed to the atmosphere for over 50 years, would be lower in 36C1 radioactivity than younger water. Thus, the 36C1]C1ratios can be used to discriminate between older and younger water that may be recharged in a catchment. The 36C1/C1 ratios of rainwater and groundwater have been used to determine the amount of water lost from catchments as a result of evapotranspiration (Paul et al., 1986; Nimz, 1998; Magaritz et al., 1990). Rainwater increases in solute, including chloride ion, con- centration as it enters the soil profile, which is due to a combination of evapotranspiration and C1 acquired from soil mineral leaching. The evapotranspiration process will increase the chloride concentration, but it does not alter the 36C1/C1 ratio, whereas the soil mineral contribution of chloride does alter the ratio. The ratio would be reduced by the addition of C1 from soil minerals. Thus, by accurate measurement of the 36C1 isotope and total chloride content of precipitation and groundwater, research hydrologists can factor out the soil min- eral contribution of chloride to the soil water and calculate the chloride contribution due to evapotranspiration. Nimz (1998) gives a detailed account of many applications of lithogenic and cosmogenic stable and radioactive isotopes, including 3H, 6Li, 7Li, 7Be, 8Be, 1°Be, l°B, liB, 14C, 22Na, 24Na, 39Ar, 41Ca, 1291, 2°4pb, 2°6pb, 2°8pb, 234U, and 238U to the measurement of the catch- ment hydrologic processes illustrated in Figure 8. For additional reading on detailed accounts of the isotope techniques used to assess and improve our water resources see a book chapter by Gonfiantini et al. (1998) and books by the IAEA (2004) and Singh and Kumar (2005). 5 MARINE RESOURCES Radioactive and stable isotopes are vital tools used by the scientific community to study and preserve our marine resources. Relating to nuclear techniques to study and preserve our marine resources the following statement was made by Professor Dr Werner Burkart in the Opening Ceremony of the Environment Exhibition on the Occasion of the 50th General 30 Introduction: Radioactivity and Our Well-Being Conference of the International Atomic Energy Agency (IAEA) on September 19, 2006, in Vienna, Austria: If we look to the large picture, climate change and global warming dominate many debates. The oceans are known to play a major part, transporting heat and acting as a sink for the carbon dioxide that we produce, and helping to regulate the earth's climate. The IAEA's Marine Environmental Laboratory in Monaco contributes to the global knowledge of these phenomena, through nuclear techniques to track ocean currents and to measure ocean climate coupling and carbon cycling. Stable and radioactive isotopes are also used to date to reconstruct past temperature, circulation and glacial events, providing the necessary data for the complex predictions that we need today.... Also in the marine environment, one of the more serious problems fac- ing some coastal waters is called Harmful Algal Blooms, or HABs for short. These often grow because of rich nutrient mixes of chemicals from industry, dwellings and agriculture discharged to coastal areas. HABs can cause the entry of toxic substances into the human food chain. Paralytic Shellfish Poisoning is one of the potentially deadly outcomes, and so shellfish have to be monitored and, if necessary, supplies regulated.