Encyclopedia of Earth: Rice (Oryza sativa L.) as a source of microelements and toxic contaminants
This article has been reviewed and approved by the following Topic Editor: Sidney Draggan (other articles)
On December 16, 2002, the United Nations General Assembly (UNGA) declared the year 2004 the International Year of Rice (IYR) under the concept “Rice is Life”. In declaring IYR, UNGA recognized that rice is the primary food source for more than half of the world’s population.
Rice (Oryza sativa L.) is considered the main staple food for several countries (Myanmar, Lao People’s Democratic Republic, Vietnam, Cambodia, Bangladesh, Indonesia, Thailand, Philippines, Nepal, P.R. China) and is a major source of nutrients. In developing countries, rice accounts for 715 Kcal/capita/day; 27% of dietary energy supply, 20% of dietary protein, and 3% of dietary fat. However, while rice provides a substantial amount of dietary energy, it has an incomplete amino acid profile and contains limited amounts of essential micronutrients.
Genetic factors, soil and weather conditions, and the use of fertilizers affect the final level of mineral and contaminant in rice. The human food chain is linked through vegetable, fruit, and tuber consumption to the nature of the soil which supplies, for example, mineral ions (copper (Cu), iron (Fe), zinc (Zn), as well as others.
On the other hand, many industrialized processes give rise to environmental problems with increased levels of contamination from such elements as arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb), which can have profoundly deleterious effects on health. The joint FAO/WHO (Food and Agriculture Organization/World Health Organization) requires detailed information on the concentration levels of elements in agricultural crops to assess the toxicological and nutritional significance of human and animal intake of these elements.