Image courtesy of Pixabay
Japan’s vast network of groundwater and springs, which has provided drinking water for thousands of years, has been nourished by deep aquifers. Scientists have discovered a new hydrological tracing technique that may help people understand the reasons for the decline in water quality of Mt. Fuji. The study was published Jan. 21 in Nature Water.
Mountain Fuji provides water to millions of people and is known locally as the “Mountain of Water”. Mt. Fuji’s spring water is thought to be supplied entirely by shallow underground aquifers close to the surface. But this model fails to account for Mt. Fuji’s complex hydrogeology and recent decline in water quality, which is thought to be linked to groundwater contamination.
Traditional groundwater level monitoring methods and classical hydrological tracers (substances that are added or inherently present in groundwater to observe flow and mixing) cannot detect vertical mixing of groundwater at different depths of Mount Fuji. To investigate possible vertical mixing, K. Smith of the Department of Earth Sciences, Shizuoka University, Japan. Nagaosa, Oliver Schilling of the University of Basel in Switzerland, and collaborators found evidence of deep groundwater injection using a combination of three unconventional natural tracers: helium, vanadium and environmental DNA (eDNA).
Based on the helium concentration found in the spring, the Fujikawa estuary fault zone — Japan’s most structurally active structure — may provide a channel for vertical water flow. They believe that the upwelling of deep groundwater with long flowing times could explain the high vanadium concentration in the spring water. The presence of microbial eDNA in Mt. Fuji springs confirms its deep groundwater source, as the environmental conditions that allow microbial growth of this particular DNA are currently only found in the extreme depths of Mount Fuji.
These findings suggest that deep groundwater is injected into the spring water of Mt. Fuji. Researchers say understanding these channels and currents could inform the prevention and management of groundwater and spring pollution. (Source: China Science News Feng Lifei)
Related paper information:https://doi.org/10.1038/s44221-022-00001-4