In order to carry out dose assessment for residents around SNPP, Zhejiang Center for Disease Control and Prevention conducted a food consumption survey of residents in Taizhou, Zhejiang Province from 2015 to 2017. Three counties in Taizhou city, Zhejiang province were chosen for this survey, using multi-stage stratified proportional to population cluster random sampling method, i.e., each site from three villages and towns (streets), each street draw two villages (neighborhood committees), every village (neighborhood committees) extract 50 families, the permanent members of each selected family (resident for at least 6 months, resident aged 3 years and above) were identified as the respondents after signing an “informed consent”.
The recorded data of the consumption frequency and average consumption amount of rice, cabbage, crucian carp, mullet and related products were collected by face-to-face survey (using the method of 24 h retrospective for 3 consecutive days). The questionnaire was based on the recommendations from China National Center for Food Safety Risk Assessment. The dietary information of all respondents under the age of 18 was provided by their guardians. According to the survey results, the average consumption of four types of food in Taizhou city, Zhejiang Province was calculated for people of different ages (grouping criteria: 3–12 years old, 12–18 years old and more than 18 years old).
The annual effective dose (AED) due to the ingestion of 137Cs and 90Sr in food was estimated using the following equation:
Where, ISr or ICs is the annual intake of 90Sr or 137Cs (Bq/year) from food. e(g)Sr or e(g)Cs is the age-dependent dose conversion coefficient for ingestion of 90Sr or 137Cs. The corresponding e(g)Sr and e(g)Cs values used in this study were according to Chinese national standards (24 ), namely, 6.0 × 10−8 Sv/Bq and 1.0 × 10−8 Sv/Bq, 8.0 × 10−8 Sv/Bq and 1.3 × 10−8 Sv/Bq, 2.8 × 10−8 Sv/Bq and 1.3 × 10−8 Sv/Bq, for people with age of 3~12 years, 12~18 years and more than 18 years, respectively.
The recorded data of the consumption frequency and average consumption amount of rice, cabbage, crucian carp, mullet and related products were collected by face-to-face survey (using the method of 24 h retrospective for 3 consecutive days). The questionnaire was based on the recommendations from China National Center for Food Safety Risk Assessment. The dietary information of all respondents under the age of 18 was provided by their guardians. According to the survey results, the average consumption of four types of food in Taizhou city, Zhejiang Province was calculated for people of different ages (grouping criteria: 3–12 years old, 12–18 years old and more than 18 years old).
The annual effective dose (AED) due to the ingestion of 137Cs and 90Sr in food was estimated using the following equation:
Where, ISr or ICs is the annual intake of 90Sr or 137Cs (Bq/year) from food. e(g)Sr or e(g)Cs is the age-dependent dose conversion coefficient for ingestion of 90Sr or 137Cs. The corresponding e(g)Sr and e(g)Cs values used in this study were according to Chinese national standards (24 ), namely, 6.0 × 10−8 Sv/Bq and 1.0 × 10−8 Sv/Bq, 8.0 × 10−8 Sv/Bq and 1.3 × 10−8 Sv/Bq, 2.8 × 10−8 Sv/Bq and 1.3 × 10−8 Sv/Bq, for people with age of 3~12 years, 12~18 years and more than 18 years, respectively.
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