Certain heavy metals which may lead peoples to poisonous status are widely used in industry and their uses have been increasing along with rapid industrialization of this co--untry.
Such an increasement of metal uses aggravates the status of environmental pollution. affecting foodstuffs which are the most important life supporting factor of animal and humanbeing.
Concerning the safety measures to minimize food-borne transmission of such hazardous metals, surveillance is the backbone of them and probably more so with a potential problem such as intoxication. Theoretically, this surveillance should include the determination of levels of heavy metal toxicants in foods, the determination of food consumption
patterns and typical total diet, and the estimation of total load of the metal contaminant from all sources of exposure including air, water, and occupati0al sources.
In recent year, actually, such estimates on the total daily intake of some heavy meta--Is from foods have been made in several developed countries andj a wide variation of date by season, locality.. and research method was recognized.
Also in this country, this kind of research data is vitally needed to make up for the serious shortage or lack of references to estimate the total amount of heavy metal intake of the people.
In this study; a modification model for estimation of the total daily intake of cadmium copper, nickel, zinc, and lead through foods was applied and concentrations of the above metals in crops cultivated in this country were measured with atomic absorption spectre photometer to get the following results.
1. Level of heavy metal concentration in crops
Generally. the levels of such metals in essential crops such as´,rice, cucumber, radish Chinese cabbage, apple, pear, grape, and orange are similar or lower than those in Japan and other developed countries. By the way, a striking ilesult on cadmium concentration was increasement of its concentration in rice from 1 0-0.035ppm in 1970 to 0. llppm in this study. However, the value is still far below 4e Japanese Permissible Lebel of 1.Oppm.
2. Estimation of total daily intake per capita from foods
A new model for estimation was devised utilizing levels of metal concentration in foods, amount of food consumed, and other food factors. Based on the above method, the daily intake of cadmium was estimated to be 70.53pg/rnan~ day in average which was as high as the Limit Value of ILO/WHO(up to 71.4pg/man/day). Also,3.89mg of Zinc, 1.65mg of cuppor, 0.32mg of lead were given as the total daily intake per capita by this research.
3. Efficacy of washing or skinning to decrease the amount of metals in crops After washing the crops sufficiently with commercial linear alkylate sulfonate, the concentration of heavy metals could be reduced to 5080% showing decreasement rate of 2050%. Also, after skinning the fruits, decreasement rate of the heavy metal
concentration showed 0-50%.
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