Epsilon Archive for Student Projects

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).