Công văn 966/BNN-QLCL về kiểm soát dư lượng phóng xạ trong thực phẩm nhập khẩu từ Nhật Bản do Bộ Nông nghiệp và Phát triển Nông thôn ban hành

Facing warnings of the World Health Organization (WHO), Ministry of Health Labor and Welfare of Japan on detection of residues of radioactive substance beyond the permissible limits in a number of foods from Japan origin; to ensure the health of Vietnamese consumers, the Ministry of Agriculture and Rural Development guides the units to deploy the uniform application of control measures as follows:

1. Control mode of radioactive contamination in food:

1.1. Subjects of application:

a. The food lots imported from Japan origin under the State management of the Ministry of Agriculture and Rural Development left Japan from 11/03/2011.

b. The inspection is done prior to the customs clearance procedures.

1.2. Frequency of inspection:

a. Sampling with frequency of 100% of the good lot to inspect radioactive contamination level of food lots imported into Vietnam originated from the provinces of Fukushima, Gunma, Ibaraki, Tochigi, Niigata, Yamagata.

b. Sampling with frequency of 20% of the good lot to inspect radioactive contamination level of food lots imported into Vietnam originated from other provinces.

1.3. Number of samples: take 01 sample/good lot with the minimum weight as 01 kg/sample.

1.4. Targets and limits:

- Short-term inspection target is to focus on three radioisotopes as follows: Cs134, Cs137 and I131.

- The allowed maximum limit for the above targets is implemented according to provisions of the Ministry of Health. If the Health Ministry has not provided for, it shall comply with the provisions of Codex standards (CODEX STAN 193-1995) - Appendix I attached.

1.5. Laboratory: Samples must be sent for analysis in the laboratories listed in Appendix II attached.

2. Measures for handling good lots having radioactive contamination exceeding the maximum permissible limit

2.1. For the good lots violated: Do not allow importing into Vietnam.

2.2. For the following good lots of the same type and origin:

a. Sampling with frequency of 100% of the good lot to inspect radioactive contamination level for the following good lots.

b. As five consecutive good lots are sampled for inspection and met the requirements, it shall be applied the mode of probability inspection.

3. Funding for the deployment

All costs for sampling, sending samples, analyzing samples shall be advanced firstly from the funds of the units. The units shall plan and estimate cost for implementing these activities and send to the Ministry (through the Department of Finance) for the Ministry’s approval.

4. Responsibilities of the units

4.1. Department of Animal Health, Department of Plant Protection:

a. To direct the units under their direct management to implement the inspection of radioactive contamination levels under the guidance of this official dispatch.

b. To coordinate with the customs authorities in inspection of imported foods, treatment and monitoring of process handling the good lots violating the above provisions.

c. Timely notify the violations and monthly report results of the inspection of radioactive contamination levels for the food lots under their management to the Ministry (through National Agro - ).

4.2. National Agro - :

a. To monitor and update information on contaminated food from Japan; measures that the competent Food Safety Authority is adopting and timely report and propose appropriate response measures of Vietnam.

b. Contact-point on the situation of radioactive contamination of foods imported from Japan under the Ministry’s state management;

c. To review the situation and the result of radioactive contamination level control in imported food originating from Japan to report to the Ministry in the monthly meeting.

d. Promptly notify the competent authority of Japan the cases detected the good lot having radioactive contamination levels exceeding the maximum allowable limits and measures that Vietnam is applying.

đ. To coordinate with the Department for Safety - Food Hygiene - The Health Ministry; and Department of Radiation Safety and Nuclear - Ministry of Science and Technology to organize the training, coaching for the officials of the inspection agency of the Ministry of Agriculture and Rural Development.

During the deployment if any difficulties, problems arise, the concerned bodies should reflect to the Ministry (through National Agro - ) for being settled.

The unit should pay attention to implement.

APPENDIX I

Tin is mainly used in tinplated containers, but it is also extensively used in solders, in alloys including dental amalgams. Inorganic tin compounds, in which the element may be present in the oxidation states of +2 or +4, are used in a variety of industrial processes for the strengthening of glass, as a base for colours, as catalysts, as stabilizers in perfumes and soaps, and as dental anticariogenic agents. On the whole, contamination of the environment by tin is only slight. Food is the main source of tin for man. Small amounts are found in fresh meat, cereals, and vegetables. Larger amounts of tin may be found in foods stored in plain cans and, occasionally, in foods stored in lacquered cans. Some foods such as asparagus, tomatoes, fruits, and their juices tend to contain high concentrations of tin if stored in unlaquered cans (Environmental health criteria for tin; International Programme on Chemical Safety (IPCS); 1980). Inorganic tin is found in food in the +2 and +4 oxidation slates; it may occur in a cationic form (stannous and stannic compounds) or as inorganic anions (stannites or stannates).

RADIONUCLIDES

* When intended for use as such.

** This represents the value for organically bound sulphur.

*** This represents the value for organically bound tritium.

Scope: The Guideline Levels apply to radionuclides contained in foods destined for human consumption and traded internationally, which have been contaminated following a nuclear or radiological emergency [1]. These guideline levels apply to food after reconstitution or as prepared for consumption, i.e., not to dried or concentrated foods, and are based on an intervention exemption level of 1 mSv in a year.

Application: As far as generic radiological protection of food consumers is concerned, when radionuclide levels in food do not exceed the corresponding Guideline Levels, the food should be considered as safe for human consumption. When the Guideline Levels are exceeded, national governments shall decide whether and under what circumstances the food should be distributed within their territory or jurisdiction. National governments may wish to adopt different values for internal use within their own territories where the assumptions concerning food distribution that have been made to derive the Guideline Levels may not apply, e.g., in the case of wide-spread radioactive contamination. For foods that are consumed in small quantities, such as spices, that represent a small percentage of total diet and hence a small addition to the total dose, the Guideline Levels may be increased by a factor of 10.

Radionuclides: The Guideline Levels; do not include all radionuclides. Radionuclides included are those important for uptake into the food chain; are usually contained in nuclear installations or used as a radiation source in large enough quantities to be significant potential contributors to levels in foods, and; could be accidentally released into the environment from typical installations or might be employed in malevolent actions. Radionuclides of natural origin are generally excluded from consideration in this document.

In the Table the radionuclides are grouped according to the guideline levels rounded logarithmically by orders of magnitude. Guideline levels are defined for two separate categories "infant foods* and "other foods'. This is because, for a number of radionuclides, the sensitivity of infants could pose a problem. The guideline levels have been checked against age-dependent ingestion dose coefficients defined as committed effective doses per unit intake for each radionuclide, which are taken from the "International Basic Safety Standards" (IAEA, 1996) [2].

Multiple radionuclides in foods: The guideline levels have been developed with the understanding that there is no need to add contributions from radionuclides in different groups. Each group should be treated independently. However, the activity concentrations of each radionuclide within the same group should be added together [3]

Annex 1

SCIENTIFIC JUSTIFICATION FOR THE GUIDELINE LEVELS FOR RADIONUCLIDES IN FOODS CONTAMINATED FOLLOWING A NUCLEAR OR RADIOLOGICAL EMERGENCY

The Guideline Levels for Radionuclides in Foods and specifically the values presented in Table 1 above are based on the following general radiological considerations and experience of application of the existing international and national standards for control of radionuclides in food.

Significant improvements in the assessment of radiation doses resulting from the human intake of radioactive substances have become available since the Guideline Levels were issued by the Codex Alimentarius Commission in 1989 [4] (CAC/GL 5-1989).

Infants and adults: The levels of human exposure resulting from consumption of foods containing radionuclides listed in Table 1 at the suggested guideline levels have been assessed both for infants and adults and checked for compliance with the appropriate dose criterion.

In order to assess public exposure and the associated health risks from intake of radionuclides in food, estimates of food consumption rates and ingestion dose coefficients are needed. According to Ref. (WHO, 1988) it is assumed that 550 kg of food is consumed by an adult in a year. The value of infant food and milk consumption during first year of life used for infant dose calculation equal to 200 kg is based on contemporary human habit assessments (F. Luykx, 1990 [5]; US DoH, 1998 [6]; NRPB, 2003 [7]). The most conservative values of the radionuclide-specific and age-specific ingestion dose coefficients, i.e. relevant to the chemical forms of radionuclides which are most absorbed from the gastro-intestinal tract and retained in body tissues, are taken from the (IAEA, 1996).

Radiological criterion: The appropriate radiological criterion, which has been used for comparison with the dose assessment data below, is a generic intervention exemption level of around 1 mSv for individual annual dose from radionuclides in major commodities, e.g. food, recommended by the International Commission on Radiological Protection as safe for members of the public (ICRP, 1999) [8].

Naturally occurring radionuclides: Radionuclides of natural origin are ubiquitous and as a consequence are present in all foodstuffs to varying degrees. Radiation doses from the consumption of foodstuffs typically range from a few tens to a few hundreds of microsieverts in a year. In essence, the doses from these radionuclides when naturally present in the diet are unamenable to control; the resources that would be required to affect exposures would be out of proportion to the benefits achieved for health. These radionuclides are excluded from consideration in this document as they are not associated with emergencies.

One-year exposure assessment: It is conservatively assumed that during the first year after major environmental radioactive contamination caused by a nuclear or radiological emergency it might be difficult to readily replace foods imported from contaminated regions with foods imported from unaffected areas. According to FAO statistical data the mean fraction of major foodstuff quantities imported by all the countries worldwide is 0.1. The values in Table 1 as regards foods consumed by infants and the general population have been derived to ensure that if a country continues to import major foods from areas contaminated with radionuclides, the mean annual internal dose of its inhabitants will not exceed around 1 mSv (see Annex 2). This conclusion might not apply for some radionuclides if the fraction of contaminated food is found to be higher than 0.1, as might be the case for infants who have a diet essentially based on milk with little variety.

Long-term exposure assessment: Beyond one year after the emergency the fraction of contaminated food placed on the market will generally decrease as a result of national restrictions (withdrawal from the market), changes to other produce, agricultural countermeasures and decay.

Experience has shown that in the long term the fraction of imported contaminated food will decrease by a factor of a hundred or more. Specific food categories, e.g. wild forest products, may show persistent or even increasing levels of contamination. Other categories of food may gradually be exempted from controls. Nevertheless, it must be anticipated that it may take many years before levels of individual exposure as a result of contaminated food could be qualified as negligible.

Annex 2

ASSESSMENT OF HUMAN INTERNAL EXPOSURE WHEN THE GUIDELINE LEVELS ARE APPLIED

For the purpose of assessment of the mean public exposure level in a country caused by the import of food products from foreign areas with residual radioactivity, in implementing the present guideline levels the following data should be used: annual food consumption rates for infants and adults, radionuclide- and age-dependent ingestion dose coefficients and the import/production factors. When assessing the mean internal dose in infants and adults it is suggested that due to monitoring and inspection the radionuclide concentration in imported foods does not exceed the  present guideline levels. Using cautious assessment approach it is considered that all the foodstuffs imported from foreign areas with residual radioactivity are contaminated with radionuclides at the present guideline levels.

Then, the mean internal dose of the public, E (mSv), due to annual consumption of imported foods containing radionuclides can be estimated using the following formula:

E = GL(A) . M(A)-eing(A) - IPF

where:

GL(A) is the Guideline Level (Bq/kg)

M(A) is the age-dependent mass of food consumed per year (kg)

eing(A) is the age-dependent ingestion dose coefficient (mSv/Bq)

IPF is the import/production factor [9] (dimensionless).

Assessment results presented in Table 2 both for infants and adults demonstrate that for all the twenty radionuclides doses from consumption of imported foods during the 1st year after major radioactive contamination do not exceed 1 mSv. It should be noted that the doses were calculated on the basis of a value for the IPF equal to 0.1 and that this assumption may not always apply, in particular to infants who have a diet essentially based on milk with little variety.

It should be noted that for 239Pu as well as for a number of other radionuclides the dose estimate is conservative. This is because elevated gastro-intestinal tract absorption factors and associated ingestion dose coefficients are applied for the whole first year of life whereas this is valid mainly during suckling period recently estimated by ICRP to be as average first six months of life (ICRP, 2005 [10]). For the subsequent six months of the first year of life the gut absorption factors are much lower. This is not the case for 3H, 14C, 35S, iodine and caesium isotopes.

As an example, dose assessment for 137Cs in foods is presented below for the first year after the area contamination with this nuclide.

For adults: E = 1000 Bq/kg -550 kg -1.3-10-5 mSv/Bq -0.1 = 0.7 mSv;

APPENDIX II

LIST OF(Together with Official Dispatch No.966/BNN-QLCL dated 14/4/2011)

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