受核事故影響食品之人體健康風險評估

Abstract

福島核電廠事故後日本食物輻射污染情形一直是國際上關注的焦點，目前台灣政府仍然維持福島在內的五縣食物進口禁令。本計畫目的乃針對日本食物受輻射污染情形，評估假若開放日本食物進口之後台灣民眾可能的輻射暴露與健康風險。本報告根據國際輻射防護委員會(International Commission on Radiological Protection 簡稱ICRP)的線性無閾值(Linear Non-threshold)原則，日本食物監測資料來自厚生勞動省每月公布的檢驗資料，扣除野生肉類、野生香菇等不可能進口的食品，與105年度國家攝食資料庫的食品品項進行配對，從二零一五年一月到二零一七年六月納入總共約八十萬筆食品檢測資料，利用貝式統計蒙地卡羅模式建立各食品中放射核種濃度的機率分佈，計算出國人攝食該品項食物所造成的內暴露分佈，再將所有食品造成的暴露加總後獲得總暴露後換算癌症機率與健康風險(New ICRP recommendations 2008 nominal risk coefficients)。 綜合上述，在保守情境之下，台灣人的暴露量在大多數的年齡層都小於百分之一毫西弗，而且可以觀察到2017年的暴露是顯著比前兩年更低，因此我們可以推論未來開放日本食物進口所造成的額外輻射暴露97.5%以上的台灣人遠小於1mSv，應該落在萬分之一到千分之一毫西弗。

After Fukushima accident, the level of radionuclides in Japanese food has been a concern worldwide. Taiwanese government has prohibited the import of Japanese food from the Fukushima, Ibaraki, Tochigi, Gunma, and Chiba prefectures since March 26, 2011 and set up the monitoring and testing system since March 15, 2011. This assessment was conducted under the situation of allowing import of all Japanese food. The internal dose and health risk were calculated. We adapted the linear non-threshold model provided by International Commission on Radiological Protection (ICRP). We used the food monitoring results from the Japanese Ministry of Health, Labour and Welfare after excluding the wildlife meat, wild mushroom which was not able to export. The food categories were matched with the National Food Consumption Database. From 2015 to July, 2017, eight hundred thousand foods were included in the assessment. We constructed the probability distribution of the contamination level of foods and internal exposure of different age groups by Monte Carlo simulation. The cancer and health risk was calculated with nominal risk coefficients. In summary, under conservative situations, the exposure of most age groups was under 0.01 mSv. We also observed the internal exposure from the 2017 japanese foods was lower than 2015 and 2016. Therefore, we expect lower internal exposure in the future and more than 97.5% of Taiwanese were far below 1mSv (about 0.001 ~ 0.0001 mSv).