Arsenic and Heavy Metals in Vietnamese Rice: Assessment of Human Exposure to These Elements through Rice Consumption

Abstract

In this work, twelve heavy metals and arsenic, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn, in a rice sample collected from some areas of Vietnam have been quantified and implemented by using multiple analytical platforms such as ICP-MS, AAS, and mercury analyser. Seventy rice samples collected from the Red River Delta and mining zone activity were analysed. Concentration of heavy metals and arsenic in rice was analysed after appropriated sample digestion using internal or external calibration curves. The mean concentration (mg kg−1 dried weight) of the analysed elements in rice samples decreased on the order of Mn (19.268) > Fe (13.624) > Zn (8.163) > Cu (3.138) > Ni (0.384) > Cr (0.296) > Co (0.279) > As (0.115) > Cd (0.111) > Pb (0.075) > Hg (0.007) > Se (<LOD). Mercury, a highly toxic element, has been only found in rice samples collected in the mining activity zone (frequency detection 14.5% of total samples). The experimental results indicated that the heavy metals and arsenic found in rice collected from mining activity zone were higher than those in rice harvested from normal cultivated areas like the Red River Delta. The heavy metals and arsenic content in Vietnamese rice samples were also compared with the concentration of heavy metals in other foreign rice samples in some recent publications. The estimated daily intake through rice consumption was calculated and compared with the level proposed by the Food and Agriculture Organization of the United Nations. The results indicated that the provisional daily intake of Cd was higher than the level proposed by FAO, while the intake of other heavy metals was in an acceptable range of CODEX standard.

Exposure to Toxic Metals from the Consumption of Rice in Lebanon and the United Arab Emirates. (c2022)

“…UAE results were also higher than the ones reported by Mohamed et al (2017) in KSA (9.36 μg/day) and Chu et al (2021) in Vietnam (0.0008 mg/kg bw/day for men and 0.001 mg/kg bw/day for women). Nevertheless, exposure of 0.0864 μg/kg bw/day assessed by Cd levels in all brands to safe levels.…”

“…CAC has not established an MRL for Hg in rice. Both Hg levels were remarkably higher than levels reported by Rothenberg et al (2015) in Madgascar (0.0011 mg/kg), Bielecka et al (2020) in Poland (0.0028±0.0026 mg/kg), and Chu et al (2021) in Vietnam (0.007±0.003 mg/kg).…”

“…• For estimating the exposure levels to toxic metals, represented as estimated daily intake (EDI), the average concentration of each toxic metal detected in the samples was multiplied by the average daily amount of rice consumption divided by the average body weight of the adult population. The calculations (Equation 2) were done according to the equation proposed by FAO (Chu et al, 2021;FAO/WHO, 2014). Equation 2:…”

“…EDI is estimated daily intake. Estimated weekly intake (EWI) was calculated by multiplying the EDI by 7 (Chu et al, 2021). Equation 3:…”

“…Similarly, Bielecka et al (2020) reported that the average As level in rice and rice products collected in Poland was 123.5±77.1 µg/kg (0.1235±0.0771 mg/kg). In Vietnam, Chu et al (2021) found that the mean contamination of Vietnamese rice with As was 0.115± 0.049 mg/kg. Another study conducted in Romania found that the mean As contamination in rice was 0.042 mg/kg (Voica et al, 2012).…”