In vitro release of aluminum from the geophagic clay "Chacco" in the Peruvian highlands: Chemical characterization and health risk assessment

Abstract

In the altiplano zone of Latin America, "Chacco" is one of the clays widely consumed as part of geophagy. The objectives of the study were to chemically characterize "Chacco", determine the zero charge point, evaluate the release of aluminum in vitro, perform the kinetic study and evaluate the health risk. The results by ICP-OES showed that the elements with the highest concentration were Al, Ba, Ca, Fe, K, Mg, Mn, Na, Si, Sr, Ti and Zn. ATR-FTIR analysis showed the presence of Si-O (693 and 990 cm⁻¹), Al-O (790 cm⁻¹), Al-Al-OH bending vibration (912 cm⁻¹), Si-H bond stretching (2100 to 2500 cm⁻¹) and free -OH groups (3629 cm⁻¹). SEM-EDX results indicate that Al is one of the main constituents of "Chacco" (7.35 wt%). The pHzpc of "Chacco" was 6.83. In the dissolution profiles, the highest Al release occurred at pH 6.8 and in intestinal juice simulated with pseudo-second order dissolution kinetics. The EDI_Al and EWI_Al were 20.24 and 142.66 respectively, comparing EWI_Al with the PTWI established by JECFA (2 mg/kg bw), it is concluded that the weekly intake of "Chacco" represents an appreciable health risk. There are no reports of the carcinogenic factor of Al, so TR_Al was not calculated.

Keywords:

• Chacco
• Aluminum
• Clay
• Geophagy
• health risk

Disclosure statement

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

Data availability statement

The data presented in this study are openly available in this manuscript.

ACRONYMS

EWI	=	Estimated Weekly Intake.
EDI	=	Estimated Daily Intake.
TR	=	cancer risk factor.
ICP-OE	=	Inductively coupled plasma-optical emission spectroscopy.
PTWI	=	Provisional Tolerable Weekly Intake.
JECFA	=	the Joint Expert Committee on Food Additives.
pHzpc	=	zero charge point.
ATR-FTIR	=	Attenuated Total Reflectance - Fourier transform infrared spectroscopy.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.