Alara principles

Similarly, airborne emission limits have been estabHshed by the NRC for nonrestricted areas. Limits of surface contamination must be estabHshed to provide a safe workplace for users (19). The appHcation of the as-low-as-reasonably-achievable (ALARA) principle to the above draws on the creative talents of the user to regard the limits as nonapproachable barriers and not as tolerable maxima for discharge. 

Some of the less adverse pollutants (called secondary pollutants) have been addressed with guidelines but the present knowledge on quantification of exposure, health data, etc makes it difficult to set official guidelines. Major research is needed on these secondary pollutants before recommendations or guidelines can be established. In the interim period, a precautionary approach should lead to an ALARA principle for these secondary causalities. 

Several potential or hypothetical relevant pollutants are discussed in the scientific literature. Their relevance to health indoors is unknown and no official recommendations or guidance can be established. Mitigation of indoor climate problems become a matter of ad hoc solution and a major research effort is needed to establish facts for these hypothetical effect exposure relations. In the meantime, an ALARA principle should be adopted for these exposures. 

The Dutch-Danish 1991 philosophy paper highlighted that the Codex definition of a contaminant does not include inherent natural toxins (e.g. the glucosinolates and phycotoxins), since these substances are present in food as a result of the metabolic processes in the organism. It was then decided to have the GSCTF also to include such toxins, as they may in many ways be similar to contaminants. Many toxins are at least as toxic to humans as most contaminants, and they may also cause problems in international trade.10 It was also recommended and agreed by the CCFAC that the GSCTF should be based upon a horizontal approach, i.e. covering the important contaminants in all relevant foods, and that the MLs should be set as low as reasonably achievable - the ALARA principle. 

The term acceptable is used to describe risks below intolerable levels that also are ALARA. Risks just below unacceptable levels are regarded as barely tolerable and normally should be reduced substantially based on the ALARA principle. Risks that are ALARA may vary from one exposure situation to another ... 

The proper interpretation of the dose limit is that higher doses (and their associated risks) from controlled sources are regarded as unacceptable, meaning intolerable. Thus, the dose limit normally must be met in routine exposures to controlled sources regardless of cost or other circumstances. Application of the ALARA principle to further control of exposures takes into account, for example, the cost of reducing radiation doses in relation to the benefits in health risks averted and other societal concerns. 

Below this level, application of ALARA principle to further risk reduction depends on the level selected as de minimis... 

A negligible dose would be generally applicable to all man-made sources of radiation and would define a dose below which further control of sources by regulatory authorities is deemed to be unwarranted. If all doses were below a negligible level, no further reductions in dose using the ALARA principle would be attempted (see... 

X 10 3. Annual effective doses in the range of 0.25 to 1 mSv from all man-made sources combined are acceptable if they are ALARA. However, doses toward the upper end of this range are regarded as only barely tolerable (ICRP, 1991), and doses below this range are expected to be justifiable and achievable in most cases, based on site-specific application of the ALARA principle. Therefore, lifetime risks from routine exposure to all man-made sources combined usually should not exceed about 1 X 10 3. 

The ALARA principle also has been used in decisions about risk management for chemicals that cause deterministic effects. RfDs often are used to define acceptable exposures to such substances. However, given the large safety and uncertainty factors often used in deriving RfDs from a NOAEL or LOAEL (see Section 3.2.1.2.4), RfDs generally correspond to doses considered negligible, and doses above an RfD may be permitted in particular situations if RfD is not achievable at a reasonable cost (see Section 3.3.2). 

When we put in a hard day s work, we want to be assured that we aren t being exposed to any unnecessary risks. Let s face it, at the end of our shift we all want to return safely to our homes in good health. Those working with radioactive materials therefore need to follow a few simple guidelines to help protect themselves from potential dangers. First and foremost, we must have a healthy respect for radioactive materials and radiation. Note that respect is different than fear. This respect will ensure that we do not get careless or complacent in our day-to-day activities. Secondly, we must maintain our exposure to radioactive materials in accordance with the ALARA principle. That is, we must maintain our exposure as low as reasonably achievable. Thirdly, three words will help enforce the... 

ALARA principle time, distance, and shielding. We should minimize our time working with radioactive materials, maximize the distance between us and the source of radiation, and use proper shielding to minimize our exposure. Finally, we must make sure that we understand and follow all the facility procedures and regulations regarding the use of radioactive materials so that our safety and that of our patients are assured. 

Other concepts used are ALARA (exposure as low as reasonable) or 7TC (threshold of toxicological concern) for insignificant low exposures. The ALARA principle intends to keep the exposure to substances at the lowest achievable level,... 

According to the JECFA, the irreducible level is defined as the concentration of a substance that cannot be eliminated from a food without involving the discarding of that food altogether, severely compromising the ultimate availability of major food supplies. Also referred to as the ALARA principle ( as low as reasonably achievable ). 

The ALARA principle is strictly enforced by the U. S. Nuclear Regulatory Commission (NRC). 

The general need for improved source control to diminish the pollution load on indoor environments from health, comfort, energy efficiency and sustainability points of view leads the EU-ECA group to the recommendation that VOC levels in indoor air should be kept as low as reasonably achievable (ALARA). Such an ALARA principle will require that TV(X concentrations in indoor environments-when determined with the proposed procedure on representative samples of buildings and spaces-do not exceed the typical levels encountered in the building stock of today, unless there are very good and explicit reasons. 

The ICRP and the IAEA regularly issue recommendations for proper handling of radiation sources. The purposes of the recommended system of dose limitations are to ensure that no exposure is unjustified in relation to its benefits, that all necessary exposure is kept as iow as is reasonably achievable (the ALARA principle), and that the doses received do not exceed the specified limits. The ICRP stresses the values given in Table 18.11 they apply to the sum of the relevant doses from external exposure in die specified period and the SO-year committed dose (for children 70 years see also next ) in the same period. These values must be respected. They are intended to limit somatic effects in individuals, hereditary effects in the immediate offspring of irradiated individuals, and hereditary and somatic effects in the population as a whole. 

All efforts must be made to reduce irradiation, the so-called ALARA principle. Especially in young children with chronic disease, repeated imaging evaluation should be as streamlined as possible. 

The Safety Rules (Radiological) are designed to ensure that specified radiation dose levels are not exceeded and that all radiation doses are kept as low as reasonably achievable (ALARA principle). All persons concerned with the control, preparation and carrying out of work involving radiological hazards, must make themselves thoroughly familiar with the Safety Rules and the supporting documents. 

Prior to the Chernobyl accident, the European Commission had never favoured proposals, originating from the European Parliament, for a Community level Nuclear Inspection Force to complement national inspectorates. However, the accident encouraged a re-evaluation of this proposal, especially its possible contribution to harmonising ALARA principles. It is probable that some member states would resist a Commission initiative in this area as strongly as they have in other areas, as outlined above. 

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