1. 140 years-long sedimentary records of PAHs and CN stable isotopes from Ninomiya River, Japan.
- Author
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Mundo R, Iwai H, Ochiai S, Matsunaka T, Hasebe N, and Nagao S
- Subjects
- Rivers, Geologic Sediments analysis, Japan, Environmental Monitoring, Isotopes analysis, China, Polycyclic Aromatic Hydrocarbons analysis, Water Pollutants, Chemical analysis
- Abstract
Anthropogenic activities' impacts over 140 years were studied at West Nanao Bay using a variety of geochemical techniques on sedimentary records. The bay is influenced by the Ninomiya River which is fed by a small watershed at which Tatzuruhama Town is located. Sedimentation rate was calculated using
210 Pb-excess and137 Cs activities. C/N decreased after 1975, indicating a decrease in lignin-rich organic matter. From δ13 C, δ15 N and biogenic silica it was indicated that the population increased sewage-discharges until the construction of waste-water treatment plant in 1986. Several recorded changes in the landuse matched with the variation of the particle size. Total PAHs concentration was 1.17-62.78 μg g-1 , being highest during Japan's fastest economic growth period (1946-1975). Using diagnostic ratios and PCA analysis, PAHs' sources were identified as pyrogenic for all depths, varying from coal combustion (90.7 %) before 1946 to a mixture of biomass and vehicle combustion after 1961., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023. Published by Elsevier Ltd.)- Published
- 2023
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