Isotopic and nuclear techniques are indispensable in many fields, including health, industry, food, and agriculture. The techniques discussed, collectively known as fallout radionuclide, fingerprint, and isotope hydrology, are currently being employed to characterize and assess phenomena that could potentially degrade soil and water resources. Given the intricate nature of erosion and sedimentation processes in landscapes and water reservoirs, conducting a comprehensive characterization and evaluation of these phenomena is imperative. A traditional literature review was conducted to obtain the most thorough understanding of both the current state of the art and the subject matter regarding the conception of these techniques’ application and the manner of their use (use combined/integrated or use isolated in search of particular results on a single type of degradation, whether soil or water). There is no evidence that an integrative methodology employing these isotopic and nuclear techniques has previously been utilized (as evidenced by 109 current publications), thereby impeding the analysis of the potential sequential occurrence of soil and water degradation. The findings substantiate the hypothesis that isotopic and nuclear techniques can be integrated sequentially through a synergistic convergence. This represents an emerging methodology for addressing the complex needs of the landscape’s soil and water degradation process.

Sedimentation processes have negative socioeconomic and environmental consequences. The Compound-Specific Stable Isotopes (CSSI) technique allows for the evaluation of sediment inputs associated with different land use changes in a study region. In the present work, this technique was used in the Alhajuela Lake sub-basin, within the Panama Canal Watershed. The role of the main soil contributors to the landscape (land uses, river, runoff, slope) relevant to the sediment load within the sub-basin of Alhajuela Lake was evaluated, and the relevant indicators in the landscape were selected in order to obtain the best representative sample. The contribution levels of three (3) representative land uses (Forest, Pasture and Sediment) in the study area were evaluated for the sediments present in sixteen (16) selected mixing points. The samples collected were subjected to the standard laboratory process to obtain the carbon chain isotopic values present in the fatty acids. The results of the determinations of the carbon chain fatty acid isotope ratios were evaluated using a Bayesian mixing model that takes into account the uncertainty present in the identified source values. According to the results obtained, the source identified as Sediment has a prominent contribution in most of the mixing points. The contributions of Forest land use are important in the mixing points located north of the study area. The contributions associated with Pasture land use are relevant in the points located in the proximity of this land use. The results suggest that landslides caused by high rainfalls events (Forest and Pasture sources) cause strong sedimentation to the north of Alhajuela Lake. At the same time, a high distribution of soils deposition is observed in the area surrounding Alhajuela Lake due to the strong presence of soils with Sediment source in these places. The results obtained are consistent with observations and measurements of the sediments accumulated in Alhajuela Lake between the years 2008 and 2012.

The isotopic and nuclear techniques discussed, namely: Fallout Radionuclide, Fingerprint, and Isotope Hydrology, are linked to the evaluation of soil and water degradation processes. A traditional literature review was conducted to gain the most comprehensive understanding of both the current state of the art and the subject matter, with the aim of proposing a hypothesis that integrates the synergistic convergence of these techniques in order to offer results that are more reliable. A case study is presented as a synthesis of the preceding discussion.

Sedimentation processes have negative socioeconomic and environmental consequences, ranging from eutrophication phenomena, loss of water quality in surface water bodies, effects on the potential for hydroelectric generation, etc. Frequently, anthropic activity is the main cause that enhances these processes through changes in land use that can lead to landscape modifications. Therefore, it is relevant to evaluate this phenomenon and to be able to discriminate the influence of different land uses on the contributions to sediment loads at different scales. The novel Compound Specific Stable Isotopes technique allows the evaluation of sediment inputs associated with different land use changes in a study region. In the present work this technique was used in the Alhajuela Lake sub-basin, within the Panama Canal Watershed. The contribution levels of three (3) representative land uses (forest, pasture and sediment) in the study area were evaluated for the sediments present in sixteen (16) selected mixing points. The main contributions of the sources to the sediments present in the main rivers and tributaries flowing into Alhajuela Lake, in the sub-basin of the same name, were identified. The results obtained are consistent with observations and measurements of sedimentation in the study area.

Isotopic and nuclear techniques, including fallout radionuclides (FRNs), fingerprinting (FP), and isotope hydrology (IH), are essential tools for assessing soil and water degradation. However, as in state-of-the-art reviews, isolated application of FRNs, FP and IH limits their potential to address complex, interconnected environmental processes across landscapes. This study proposes a novel methodology based on the concept of Synergistic Convergence to integrate FRNs, FP, and IH into a unified framework for assessing soil and water degradation. Validated through a case study in Cuba’s Hanabanilla sub-basin, the five-stage methodology improves the identification of erosion hotspots, sediment sources, and water resource vulnerabilities. Results demonstrate that combining FRNs (quantifying soil redistribution), FP (tracing sediment sources), and IH (evaluating water dynamics) provides a robust approach for sustainable landscape management, according to the United Nations Sustainable Development Goals (SDGs) and the One Health framework. The integrated methodology proves superior to the non-integrated approach, connecting causes (erosion), drivers (water), and consequences (sedimentation, pollution). The Synergistic Convergence methodology effectively integrates isotopic and nuclear techniques (INTs) (FRNs, FP, and IH), enabling a holistic assessment of soil and water degradation and their interactions within terrestrial and aquatic ecosystems.