From the paper:
Very little is known about the role of groundwater in delivering carbon to surface waters.1 Dissolved organic and inorganic carbon concentrations in groundwater are often much higher than those in surface waters. Therefore, groundwater seepage may play a significant role in carbon budgets in freshwater and marine ecosystems even if the volumetric contribution is small. In river systems, some of the base flow seepage is automatically included in downstream river carbon measurements.1 In marine and estuarine systems, however, site specific measurements are needed to resolve the contribution of submarine ground water discharge (SGD) to carbon budgets. The modern definition of SGD includes both a terrestrial (freshwater) and a marine(recirculated seawater) component.2 While fresh groundwater is a source of “new” water and carbon, recirculated seawater can be a source of “recycled” organic matter respiration products such as nutrients and carbon dioxide.3,4Recent technological advances (i.e., automation5) have increased our ability to assess groundwater discharge in complex systems using natural tracers such as radon (222Rn, half-life = 3.84 days). Radon is a biogeochemically conservative noble gas and a member of the 238U decay chain.6 Since uranium is present in nearly all sediments and has a half-life of billions of years, any water that remains in contact with sediments for at least several hours acquires a radon signal.
The bold is mine, but let me repeat that, in case you missed it: "Since uranium is present in nearly all sediments and has a half-life of billions of years, any water that remains in contact with sediments for at least several hours acquires a radon signal."
In my polls, which are often more popular than my diary texts, I sometimes like to give a poll choice that involves "banning uranium."
This is a joke. As I noted in other places (most recently in a diary called How Radioactive is the Ocean?), the oceans on this planet contain about 5 billion metric tons of uranium. This is not all the uranium that there is on this planet, but only represents the amount that can be dissolved in seawater. If one were to remove this uranium from the ocean, it would recharge from the earth's crust, including crustal land rocks.
But I like to tempt anti-nukes to ban the earth's crust. They're so cute when they do that.
The only way to get rid of uranium (and thus radon with which it is always in radioequilibrium) is to fission it in nuclear reactors. Fissioning uranium actually reduces the number of radioactive decays that uranium must go through to become nonradioactive (in the form of lead). Also most of the fission products, when they reach the ground (non-radioactive) state are less toxic than lead. For instance one fission product is the element cerium, which is widely used in making self cleaning ovens and lots of other stuff with which you may be familiar.
An attempt to fission the 5 billion tons of uranium in the uranium would involve the generation of about 400 million exajoules, or about 80% of 750,000 years of human energy consumption as of this writing, which is currently at about 520 exajoules per year. However, again, the attempt to remove this uranium from the oceans would necessarily fail, since, as soon as it is removed, more (from the crust and mantle) dissolve.
Anyway, to return to the matter of CO2 and uranium, the paper says:
The radon and the carbon dioxide scientific communities have evolved independently in the last several years. Several radon investigations evoke the carbon cycle to justify the need for studying groundwater surface water exchange,3 and several carbon cycle investigations put groundwater discharge in the“to do” list.9,14,15 In addition, much of the groundwater community has focused on modeling studies from a water resources rather than a carbon cycle perspective. In this paper, we contribute to bridging the gap between these communities by demonstrating that automated, high precision, high-resolution radon and carbon dioxide measurements can be easily performed simultaneously using portable gas detectors. We report the results of laboratory experiments designed to assess the performance of six gas equilibration devices and the first coupled, automated 222Rn-pCO2 field measurements.
The paper goes on to show that indeed, radon and carbon dioxide concentrations in a particular area are, in fact, correlated, and since the radon can only
come from ground water, the method represents a way of measuring carbon flows from ground water.
The flow of carbon dioxide in groundwater would, in theory, be relevant to studying the leach rates from all those silly carbon dioxide sequestration fields that people, including some anti-nukes, are always talking about. In their lexicon, a few tens of thousands of tons of used nuclear fuel, consisting largely of wholly insoluble materials cannot be stored for a few million years, but hundreds of billions of tons of a highly soluble gas can be stored, for eternity.
Life is so bizarre sometimes.
Anyway. I live in Western New Jersey, at the edge of the large geological feature known as the Reading Prong, which is a natural uranium formation. My basement does have radon in it: I've measured it, using kits supplied by my town government.
Shattering rocks, as the gas companies are doing with lots of cheering from the peanut gallery, to "frack" for gas - increases the available surface area for equilibrium radon to leak from these rocks. When the gas is gone, as the half-life or uranium is about the age of the earth - 4.5 billion years - the radon will continue to leach: Forever.
Similarly the dangerous fossil fuel waste that is released by burning the fracked gas will probably also remain essentially forever, or at least until the climate in which you and I were born is no longer recognizable.
But don't worry: Be happy. It's "economical."
The only way to stop radon leaching from shattered crustal rocks beneath New Jersey, Pennsylvania and New York will be to remove the uranium and fission it.
That probably won't happen though, because, of fear, ignorance and superstition.
It's been a pleasure to chat with you all. Have a nice day tomorrow.