Comment on “Radioactive Concentrations in Chemical Fertilizers”

A more detailed explanation is needed to fully understand the paper 'Radioactive concentrations in chemical fertilizers' by Kim and Cho [1], published in the Journal of Radiation Protection and Research.This paper reports the measurement of radioactivity levels in five types of fertilizers, with basic data generated on their environmental impact and public radiation safety.According to the findings of this paper, 134 Cs was detected in domestically distributed fertilizers at levels ranging from approximately 34.43 Bq/kg to 94.76 Bq/kg, whereas 137 Cs was detected at levels ranging from 2.21 Bq/kg to 5.74 Bq/kg; 40 K was detected at levels ranging from 347 Bq/kg to 70,007 Bq/kg.However, these results appear to conflict somewhat with previous studies.The detection of 134 Cs and 137 Cs in domestic soil is covered in the paper titled ' 134 Cs and 137 Cs 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 134 Cs and 137 Cs if originating from the Fukushima accident, observing 134 Cs of up to 17 Bq/kg and 137 Cs of up to 109 Bq/kg.Given that 134 Cs has a short half-life of approximately 2.1 years, the 134 Cs found in fertilizers cannot be attributed to the Fukushima accident.In addition, the ratio of 134 Cs to 137 Cs 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 137 Cs 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 40 K is 30.6 Bq/g in accordance with International Atomic Energy Agency (IAEA) SRS-49 due to the natural abundance of 40 K 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.