Tritium as a Tracer of Leachate Contamination in Groundwater: A Brief Review of Tritium Anomalies Method

Abstract

Environmental isotopes are essential in hydrogeological studies, thanks to their contribution to the understanding of aquifers dynamics, vulnerability, water resources assessment, and management issues. The environmental isotopic approach plays a vital role in tracing the hydrological cycle and identifying various sources of contamination in the environment and gives independent information concerning what can be determined by a traditional hydrogeological study. Even in the framework of COP-26, isotopes have been indicated as fingerprints of climate change and therefore suitable for the evaluation of water balance and assessment of processes involved therein; in pollution studies they are used as fundamental support of traditional geochemical measures. Tritium, in particular, has been used since the 1960s to identify potential leaks in the containment walls of waste disposal sites, since its presence in the leachate (at very high levels in some cases) depends on the incorrect waste disposal of some peculiar items. Its use as a tracer of pollution by landfills is highlighted and emphasized by the very low concentrations of tritium in the natural environment. By comparing tritium content of leachate to that of water downflow from the waste disposal site, it is therefore possible to establish with a good success rate whether leachate have migrated or not out of the landfill, in the surrounding environment. An additional potential of tritium is to give a prompt indication of pollution risk in the environment indicating leaching even before the chemical indicator of pollution can be detected. This article wants to provide a contribution to the scientific community, collecting all the existing research in this field and providing data and benchmarks about this method, in particular stressing the role of tritium as an indicator of leachate transfer out of waste disposal sites.

Carbon and Sulfur Isotope Methods for Tracing Groundwater Contamination: A Review of Sustainable Utilization in Reclaimed Municipal Landfill Areas

“…The relatively distinct isotopic ratios or signatures of substances, created through biogeochemical processes, offer great potential for tracing contaminants such as leachates around the landfill [14]. The most frequently used environmentally stable isotopes are as follows: δ 13 C DIC (CO 3 2− and HCO 3 − ), δ 34 S (SO 4 2− ), δ 2 H, and δ 18 O of water molecules; δ 15 N and δ 18 O (NO 3 − ) [14,27,44,46,[60][61][62][63][64][65][66][67][68][69][70][71][72]; and radioactive isotopes 3 H, 14 C, 87 Sr, 36 Cl, and 11 B [73][74][75][76][77][78][79]. Satisfactory results are obtained on the basis of carbon and sulfur isotope tests, which are easy and friendly to use and are characterized by appropriate precision.…”

Characterization of geological and lithological features in the area proximal to tritium-contaminated groundwater at the Semipalatinsk test site

“…Different radionuclides behave differently in groundwater and geological environments, depending on the physicochemical factors. Notably, among all existing radionuclides, tritium, having high migration capacity, is an indicator of the dynamics of transportation by groundwater [6][7][8][9][10].…”