Major and minor element contents of calabash clay (nzu) from Abia State, Nigeria: evaluation of potential intake benefits and risks

Abstract

Major and trace elements were determined in nzu (calabash clay) from Abia State, Nigeria, by atomic absorption spectrophotometry. Mean calcium content was 1900 ± 100 mg/kg dry weight, followed by Na 1400 ± 96, Fe 1500 ± 480, K 260 ± 150, and Mg 100 ± 48 mg/kg. The mean concentration of Zn was 35 ± 5, Cu 16 ± 2.0, Mn 17 ± 5.0, Cr 10 ± 1.0, Ni 9.0 ± 2.0, Cd 4.3 ± 1.7, Co 3.9 ± 1.1, and Pb 3.0 ± 0.8 mg/kg. The contents of Ba and V were <0.4 mg/kg. The mean Pb content was higher than the WHO safe limit (0.4 mg/kg) and EU (1 mg/kg) limit for food. Estimates of daily intake of Cd, Cr, Fe, and Ni upon consuming 30–80g of nzu were above the recommended daily intake values. The Ba, Ca, Co, K, Mg, Na, and Zn contents should not exceed the recommended daily intake while Cd, Ni, and Pb would pose health risks, especially in pregnancy. The total target hazard quotient indicated potential health risks to consumers.

Keywords:

• nzu
• trace metals
• Nigeria
• calabash clay
• lead

Acknowledgments

Technical assistance and contributions of Anyim Ejieke Okorie, Ugochukwu Ewuzie, Obasi Kalu, Ihejirika Chinemerem, and Lydia Uche, all of Abia State University Uturu, and of Joan Iheoma Oji of FCT Education Resource Centre, Abuja, are acknowledged. The author wishes to express his sincere thanks to the reviewers of the manuscript. Their suggestions and comments significantly contributed to improving the quality of this publication.

Disclosure statement

No potential conflict of interest was reported by the author.