Exposure assessment of the population in Poland to the toxic effects of arsenic compounds present in rice and rice based products

Abstract

Background: Rice is a staple food for many people in the world and an important ingredient for production of food for infants and young children. According to European Food Safety Authority (EFSA), cereals, primarily rice and rice products, are an important source of human exposure to inorganic arsenic, which has been classified by the International Agency for Research on Cancer (IARC) as group I carcinogen. Arsenic is present in rice and rice products mainly as an inorganic form being more toxic than organic compounds

Objectives: The aim of the study was to determine the total and inorganic arsenic content in rice, rice-based products including food for infants and young children available on the market in Poland and thus to estimate consumer exposure to inorganic arsenic from these groups of foodstuffs

Materials and methods: A total of 62 samples of rice and rice products from trade, including a group of rice products for infants and young children, were tested. Contents of total and inorganic arsenic were determined by using hydride generation atomic absorption spectrometry (HGAAS), after dry mineralization of samples and reduction of arsenic to arsenic hydride with sodium borohydride. To extract the inorganic arsenic forms, the samples were subjected to hydrolysis in concentrated HCl and then reduced in the presence of hydrobromic acid and hydrazine sulphate after which triple chloroform extractions and triple 1M HCl re-extractions were performed. Exposure of different groups of populations (adults and children), was estimated in relation to the Benchmark Dose Lower Confidence Limit (BMDL05) as set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) that resulted in a 0.5% increase in lung cancer (3.0 µg/kg body weight (b.w.) per day)

Results: Mean content of total and inorganic arsenic in investigated rice samples was 0.12 mg/kg (median: 0.09 mg/kg; 90th percentile 0.22 mg/kg) and 0.04 mg/kg (median: 0.03 mg/kg, 90th percentile 0.07 mg/kg). Brown rice was found to be more highly contaminated with both total and inorganic arsenic than white rice. Mean contamination of brown rice with total arsenic and inorganic arsenic was: 0.18 mg/kg (median: 0.12 mg/kg, 90th percentile: 0.32 mg/kg) and 0.05 mg/kg (median: 0.05 mg/kg, 90th percentile: 0.07 mg/kg). In turn for the white rice contamination was lower, mean total arsenic content: 0.10 mg/kg (median: 0.08 mg/kg, 90th percentile: 0.19 mg/kg) and mean inorganic arsenic: 0.03 mg/kg (median: 0.03 mg/kg, 90th percentile: 0.06 mg/kg). Contamination of rice-based products both total and inorganic arsenic was similar to those reported for rice, except rice wafers (mean: 0.24 mg/kg and 0.13 mg/kg). In the group of products for infants and young children obtained results were low – mean total arsenic content was 0.06 mg/kg and inorganic arsenic 0.02 mg/kg. The estimated average adult and children’s exposure to inorganic arsenic with rice and rice products was less than 1% of the BMDL05. Intake of inorganic arsenic by 12-month-old infants with ricebased products intended for this group of population was at 6% BMDL05

Conclusions: Based on the obtained results, it was found that the content of total and inorganic arsenic in investigated samples of rice and rice products did not pose a health risk even though contamination levels in some individual samples were significant

Keywords: total arsenic; inorganic arsenic; rice; rice products; food for infant; food for young; exposure assessment.