Examining dietary cadmium exposure levels within the population of a metal recycling village in Bac Ninh Province, Vietnam
Abstract: Consumption of food crops contaminated with heavy metals is a major problem in many developing countries. This report examines the dietary cadmium (Cd) exposure levels within the population of a metal re-cycling village in northern Vietnam, close to the city of Hanoi. Calculations were performed in order to discover whether levels of exposure via the major diet contributors, rice, water spinach, and fish, exceed doses that have been associated with deleterious health effects. The highest concentrations of Cd were found in rice while the lowest were found in water spinach. The mean values of the Hazard Quotient (HQ; ratio of exposure to a 'safe' dose) for Cd were:3.77x100 for rice, 1.14 x 10- 1 for fish and 4.30 x 10-2 for water spinach. These values indicate that the dose associated with the consumption of rice exceeds the 'safe dose' as defined by the United States Health Protection Agency (U.S EPA). Values of HQ greater than 1.00 are considered to indicate a possible health risk. The mean value for concentration of Cd in rice was 0.46 mg Cd kg-1 (ppm), this value exceeds the limiting values set by EU (0.2 ppm) and WHO (0.4 ppm). This means that the rice in the village Man Xa is not suitable for human consumption. The mean HQ for fish and water spinach was less than 1.00, so deleterious health effects caused by these are less probable. However, the Cd concentrations in fish and water spinach was not analysed for the study village but in other villages in periurban Hanoi. There was no statistical evidence that there could be a difference between gender and the HQ for rice, fish and water-spinach. The average HQ for rice was greater in the age over 60 year compared to the ages under 60 year. For consumption of rice all age groups exceeded the safe reference dose set by U.S EPA (2008). For fish and water spinach the highest average HQ was found in the age group 13-60 years old. None of the age group for consumption of fish and water spinach exceeds the reference dose set by U.S EPA (2008).
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