Human health risk assessment of arsenic, cadmium, and zinc exposure through rice consumption in Bangkok

Abstract

The objectives of this study were to 1) determine the levels of arsenic (As), cadmium (Cd), and zinc (Zn) in rice sold in local markets of Bangkok using an inductively coupled plasma – mass spectrometry (ICP-MS) and an inductively coupled plasma – optical emission spectrometry (ICP-OES) 2) assess both non-carcinogenic and carcinogenic effects as a result of rice consumption on a daily basis, and 3) determine the bioavailability of metals in rice. The average total metal concentrations (average ± SE) in rice (n=97) were 0.2049 ± 0.0081 mg kg-1 for As, 0.0189 ± 0.0012 mg kg-1 for Cd, and 19.79 ± 0.80 mg kg-1 for Zn. Concentrations of As in rice grain were influenced by type of rice in which brown jasmine rice was found with the highest As contents. In addition, As was the only substance showing the hazard quotient (HQ) value above the threshold level (HQ > 1). HQ values of As in adults ranging from 1.17 to 2.61 for different types of rice consumption. The average HQ values of Cd and Zn exposure in adults ranged from 0.04 to 0.09 and 0.11 to 0.28, respectively. Comparing to the other age groups, the highest HQ values for each rice type consumption were found in children. Moreover, HQ values of male were usually in the higher level than female. The annual excess lifetime cancer risk (AELCR) caused by As exposure with the value of 3×10-8 (acceptable range 10-6 -10-4) indicated a low possibility of cancer development. Finally, the bioavailable As concentrations were found to be 15.7% in white jasmine and 33.3% in brown jasmine rice.