Question

If you eat a 48 g serving rice every fourth day and you weigh 75 kg, what is your dose of inorganic arsenic (in µg per kg body weight per day) if the rice contains 386 µg kg^-1 of total arsenic, 45% of which is inorganic arsenic.

Answer 1

Total Arsenic = 386 µg kg^-1

Inorganic Arsenic is 45% of this

Therefore, inorganic arsenic = 386 µg kg^-1 x 45 / 100 = 173.7 µg kg^-1

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The above statement means,

1 kg of rice contains 173.7 µg of inorganic arsenic.

Therefre 48 g = 0.048 kg of serving rice will contain 173.7 x 0.048 µg of inorganic arsenic. = 8.3376 µg of inorganic arsenic.

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8.3376 µg is the dose of inorganic arsenic.for 75 kg body weight for every fourth day

In other words.the dose of inorganic arsenic.for 75 kg body weight for every fourth day = 8.3376µg

Therefore,the dose of inorganic arsenic.for 1 kg body weight for every fourth day = 8.3376 µg /75 kg = 0.111168 µg per kg^-1

Since the rice containing the inorganic arsenic.is taken only once in four days, the dose of inorganic arsenic in µg per kg body weight per day will be one-fourth of the above quantity

Hence the dose of inorganic arsenic in µg per kg body weight per day = 0.111168 µg kg^-1 body weight /4day = 0.027792 µg kg^-1 body weight day ^-1 = 0.027792 µg per kg body weight per day

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