Molybdenum Isotopic Fingerprints in Taiwan Rivers: Natural versus Anthropogenic Sources

Two rivers from Taiwan with different source inputs, the Danshuei (polluted) and Liwu (non-polluted), were selected to study behavior of molybdenum (Mo) isotopes during weathering riverine transport. In River, δ98/95Mo ranges 0.83‰ 1.50‰ (wet season) 0.54‰ 1.25‰ (dry season). With a few exceptions, in River is lighter wet season, while, contrast, heavier dry season. varies 1.30‰ gets along mainstream. Using MixSIAR model, three Mo sources are identified River: seawater intrusion, rock–water interaction, anthropogenic inputs. Seawater intrusion can explain heavy downstream signal season contributing 14–39% model. However, most likely due inputs middle lower reaches 75–98%. dissolved correlate SO42−/Na (Sr/Na) ×1000 ratio, suggesting that pyrite oxidation coupled carbonate governs signature, sequestration light into secondary mineral phases bedload sediments. Furthermore, these results have important implications for ocean, controlled by activity processes.