Investigation and assessment of natural radioactivity in commercial animal feeds in Texas

Abstract

Commercial animal feed in Texas was characterized by determining natural gamma emitters including ⁴⁰K,¹³⁷Cs, and Uranium (²³⁵U and ²³⁸U) and Thorium (²³²Th) series to obtain basic radioactivity values. The measured activity concentration of natural radionuclides in animal feed was low enough for safe consumption by animal and largely depended on the type of animal feed.⁴⁰K was the predominant radionuclide showing the highest activity concentration in animal feed. The radioactivity concentration of ²¹⁴Bi and ²¹⁴Pb in ²³⁸U decay series was 1.39 and 1.33 Bq/kg in corn, respectively, lower than in other animal feed types. On the other hand, the vitamin/mineral mix samples showed higher concentrations of ²¹⁴Bi (9.04 Bq/kg) and ²¹⁴Pb (10.19 Bq/kg). Beef cattle feed, poultry feed, and vitamin/mineral mix exhibited higher activity concentration of ²²⁸Ac and ²¹²Pb in ²³²Th decay series. Gamma radionuclides appeared to be highly and significantly correlated within each decay series. ²³⁵U was present at low levels in all feed samples while the anthropogenic radionuclide of ¹³⁷Cs was not detected irrespective of the type of animal feed. This study highlights an importance of establishing a current baseline of radioactivity concentration in animal feed in Texas in which the largest animal feed consumption in the US exists.

Keywords:

• Animal feed
• gamma emitters
• Uranium series
• Thorium series
• ¹³⁷Cs

Acknowledgements

The authors are thankful to staffs and administrations of the Office of the Texas State Chemist, Texas A&M AgriLife Research for their support and financial assistance offered for this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).