Dataset on Cs-137 in waters surrounding Taiwan

Area of Science:

• Marine Chemistry
• Radiological Science

Background:

• The Fukushima Daiichi nuclear accident released anthropogenic radionuclides, Cesium-134 (Cs-134) and Cesium-137 (Cs-137), into the marine environment.
• These soluble radionuclides can serve as tracers for oceanographic studies, despite lower quantities compared to historical atomic bomb tests.
• Understanding the distribution of these isotopes is crucial for assessing oceanic transport and potential environmental impacts.

Purpose of the Study:

• To investigate the presence and distribution of Cesium-137 (Cs-137) in seawater around Taiwan.
• To utilize Cs-137 as a tracer to understand ocean currents and water mass origins in the region.
• To establish a baseline dataset for Cs-137 activity in the studied marine areas.

Main Methods:

• Collection of seawater samples from various locations around Taiwan, including the Kuroshio, northern South China Sea, Taiwan Strait, and southern East China Sea.
• Analysis of Cs-134 and Cs-137 activity concentrations in collected seawater samples using gamma spectrometry.
• Archiving of comprehensive data, including sampling parameters (date, location, depth, temperature, salinity) and radionuclide activity.

Main Results:

• Cesium-134 (Cs-134) was consistently below the detection limit in all analyzed seawater samples.
• The average surface Cs-137 activity concentration measured was 1.18±0.25 Bq m⁻³.
• A total of 577 samples were analyzed, providing extensive data on Cs-137 distribution.

Conclusions:

• The study confirms the presence of Cesium-137 (Cs-137) in the marine environment around Taiwan, originating from the Fukushima accident.
• The absence of detectable Cesium-134 (Cs-134) suggests that the observed Cs-137 is likely from older sources or has undergone significant decay and dispersion.
• The collected dataset provides valuable information for oceanographic research and monitoring of radionuclide distribution in the Western Pacific.