Using gamma ray spectrometry for fingerprinting sources of estuarine and coastal sediment in Mukawa coast, Hokkaido, northern Japan
Abstract
To seek the geological tracers of environmental radionuclide for fingerprinting sources of estuarine and coastal sediment, the gamma ray spectrometry was conducted for the soil and sediment samples collected from subcatchments, rivers, estuaries and coast in Mukawa and Sarugawa river watersheds and Mukawa coast, Hokkaido, northern Japan. Gamma ray spectrometry was conducted to determine the activities of environmental radionuclides associated with each soil and sediment samples using HP Ge well-type detector. Gamma ray spectrometry could determine 15 environmental radionuclides, including U-series, Th-series, cesium-137 and potassium-40. Lead-210 excess was also determined by subtracting the activities of Pb-214 from that of Pb-210. The Kruskal-Wallis H test was conducted to assess the ability of each tracer property to discriminate between surface soil samples from the categories divided by subcatchment, geological era and period, suggesting that more than 11 tracer properties were available. Subsequently, the stepwise discriminant function analysis was conducted to identify which combination of tracer properties provides the best composite fingerprint for differentiating source materials on the basis of subcatchment and geology source groups. This analysis suggested that the composite fingerprints of Pb-212, Ac-228 and K-40 can classify the geology into 6 groups based on rock type. Using these tracer properties, the contribution of rock to estuarine and coastal sediment can be evaluated with the multivariate sediment mixing model.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMOS31B1419M
- Keywords:
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- 1858 HYDROLOGY / Rocks: chemical properties;
- 1862 HYDROLOGY / Sediment transport;
- 4235 OCEANOGRAPHY: GENERAL / Estuarine processes;
- 4546 OCEANOGRAPHY: PHYSICAL / Nearshore processes