However, these results appear to conflict somewhat with previous studies. The detection of ¹³⁴Cs and ¹³⁷Cs in domestic soil is covered in the paper titled ‘¹³⁴Cs and ¹³⁷Cs radioactivity in soil and moss samples of Jeju island after Fukushima nuclear reactor accident’ [2]. The radioactivity levels in the soil of Jeju island were measured to detect the ¹³⁴Cs and ¹³⁷Cs if originating from the Fukushima accident, observing ¹³⁴Cs of up to 17 Bq/kg and ¹³⁷Cs of up to 109 Bq/kg. Given that ¹³⁴Cs has a short half-life of approximately 2.1 years, the ¹³⁴Cs found in fertilizers cannot be attributed to the Fukushima accident. In addition, the ratio of ¹³⁴Cs to ¹³⁷Cs in the soil of Jeju island was reported to be 0.3, which differs from the ratio of Cs in fertilizers.

According to National Council on Radiation Protection and Measurements (NCRP) Report No. 154, approximately 90% of ¹³⁷Cs originates from nuclear testing, 6% from the Chernobyl accident, and 4% from nuclear fuel reprocessing facilities [3]. Therefore, the presence of Cs in fertilizers may indicate previously undetected leaks of other radioactive substances. Furthermore, maximum activity concentration of ⁴⁰K is 30.6 Bq/g in accordance with International Atomic Energy Agency (IAEA) SRS-49 due to the natural abundance of ⁴⁰K in the environment [4]. But this paper shows 70 Bq/g in the phosphoric acid. Therefore, a more detailed examination should be conducted regarding the results of the paper, especially concerning the origin of the detected radionuclides and their potential implications.