Improvements in water resources management using nuclear and isotopic techniques

By studying isotopes, scientists can discover the origin, age, quality, and use of water, gathering data to protect this natural resource.

Some examples of the application of these techniques are given below:

Groundwater study

Las aguas subterráneas se filtran desde la tierra y la arena de las primeras capas de seulo hasta las superficies rocosas más profundas o "acuíferos", donde se acumulan y se desplazan lentamente.

En algunas regiones, estas aguas constituyen el principal recurso hídrico, debido a la disminución de la cantidad y la calidad de las aguas superficiales en los ríos, lagos y embalses. Estas condiciones provocan inseguridad alimentaria por la pérdida de cultivos y el no poder satisfacer las necesidades básicas de una población que está en cosntante crecimiento.

El uso creciente de las aguas subterráneas exite una mayor compresión de los factores que afectan a los patrones de las precipitaciones y de los nexos entre la recarga y la descarga (movimientos del agua desde la superficie hasta los acuíferos y viceversa).

Por lo tanto, con técnicas isotópicas se puede hacer un estudio regional para medir las interacciones entre las precipitaciones y la dirección y la magnitud del flujo de agua por encima y debajo del suelo, monitorear la concentración de radio (un material radiactivo natural) presente en el agua por diversos procesos naturales derivados de la geología y la geoquímica del lugar o explora opciones para el tratamietno del agua.

Los resultados obtenidos pueden ser de utilidad para los responsables de formular políticas que protegan las zonas de recarga indispensables para el uso sostenible y seguro del agua o construir instalaciones con unidades de tratamietno del agua que usarán óxido de manganeso hidratado para eliminar el radio del agua.

Uso responsable del agua en entornos agrícolas

The International Atomic Energy Agency (IAEA), in collaboration with the Food and Agriculture Organisation of the United Nations (FAO), is assisting 50 countries in this area.

In East Africa, increasingly frequent droughts are a threat to staple foods such as bananas. The region produces about 20% of the world's bananas and part of its population lives from banana cultivation.

Isotopic techniques can be used to analyse carbon-13 in bananas, and other data can be used to make production more water-efficient, leading to the creation of climate-smart banana farming systems.

Carbon-13 is used to measure carbon dioxide and understand how it is absorbed and released by the plant.

Water balance management using the tritium-helium 3 technique

One of the key factors in establishing a reliable water balance is to know the exact age of the water as it provides information on its source, its recharge rate, and the likelihood of it being contaminated.

Tritium is one of the three isotopes of hydrogen. As a radioactive isotope, tritium decays over a certain period to helium-3, a stable, non-decaying isotope. Therefore, on the basis that in the 1950s and 1960s, there were high levels of tritium in the atmosphere that have been gradually decaying to helium-3 ever since, although he considers tritium a good tracer, together with helium-3 it gives a much more accurate level of detail of information.

From their experience, scientists know that it takes about 12 years for half of the tritium atoms in water to decay into helium.

Helium is a noble gas, which means that it is stable and does not react chemically with other elements in rocks or water. This makes it a constant and reliable reference point. Scientists can determine the exact age of young water if they know the concentration of helium from tritium (helium-3) relative to the total amount of helium in the water, as well as the concentration of other noble gases.

This technique is one of the most common for studying young water, less than 60 years old, which is more susceptible to climatic conditions and contamination, scientists use the tritium/helium trend to find out its age, which can be anywhere from a few months to millions of years.

They use a mass spectrometer to sort the isotopes by weight and determine their respective concentrations. Once they know these and the time it takes for tritium to convert to helium-3, scientists can track the isotopes and determine the age of the water and how often it is recharged.

If it is one year old, for example, it will take a year to recharge and is much more likely to be affected by weather conditions and pollutants than if it is 50,000 years old.

The information gathered can help decision-makers formulate better-targeted and more sustainable water management strategies and policies.