ELSEVIER

J. Environ. Radioactivity, Vol. 32, Nos 1-2, 3-17, 1996 pp.

Copyright 0 1996 Elsevier Science Limited

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0265-931X(95)00076-3

Technologically Enhanced Radioactivity: An Overview

M. S. Baxter

International Atomic Energy Agency, Marine Environment Laboratory, BP No. 800, MC 98012, Monaco

(Received 1 September 199.5; accepted 10 November 1995)

ABSTRACT

Man first increased his radiation exposure above the natural baseline when he began cave-dwelling and mining and working metals and minerals. Since then the understanding of technologically enhanced radioactivity and of the associated exposure pathways has increased to the present state which is described by UNSCEAR (1993, Sources and effects of ionizing radiation, UN Scientific Committee on the Effects of Atomic Radiation, Report to the General Assembly, UN, New York) as ‘sketchy ‘and ‘not sufficient to enable reliable estimates’. This review ofpresent-day knowledge suggests that many non-nuclear industries are indeed capable of generating significant critical group or collective exposures or both. Doses can be delivered to workers and to populations living in the vicinity of industrial sites. Notable amongst these types of industry are the phosphate-processing industries (jertilizers, deter- gents, chemicals), ,fossil-fuel burning, oil and gas extraction, mining oj almost all kinds, ore and heavy mineral processing and the,forest industries, such as pulp making and biojiiel use. There is a growing awareness of the problem but a two-tier system of radiation protection and discharge control is liable to continue, particularly in developing countries, with an imbalame in the understanding and limitation of radioactivity emissions from non- nuclear versus nuclear industries and also in radiological protection oj workers. This review, covering historical and current aspects, suggests that there is a need for .further study of technological enhancement of radio- activity and that the first international conference dedicated to the subject is extremely worthwhile and should become the first landmark meeting in a long and important series. Copyright I:(? 1996 Elsevier Science Ltd.

M. S. Baxter

BACKGROUND

The most nuclear technological production process was the first. Nucleosynthesis, the formation of matter by nuclear reactions, led to the production of more than 5000 different types of atoms, nuclides, of which more than 95% are radioactive. The ubiquitous distribution of these radioactive nuclides has resulted in the powering of geological processes through radioactive heating, while the radiation environment has been a significant contributor to the creation and evolution of life. Of course, it is nuclear fusion energy that provides the primary energy source within the universe so that we can safely assert that the first technological enhancer of radiation and radioactivity was The Creator himself. In this paper, however, it is the ubiquity of radioactivity in natural materials, e.g. minerals, fossil fuels, wood, which is seen to underpin the phenomenon of technological enhancement of that radioactivity and, in certain industries, to lead to significant exposures to radiation by industrial workers or by the surrounding population or both. It is fair to say that, as soon as early man moved, for reasons of safety and warmth, into cave environments, he first became exposed to enhanced radioactivity through inhalation of extra radon, and perhaps additional external gamma exposure, the radon concentrations perhaps being further increased by the hanging of the odd animal skin across the cave entrance! Of course, the move to the cave reduced the risks of being attacked by a wild animal so that the additional radiation risk was certainly worth being subjected to and, in the discussion that follows, the cost benefit analysis factor must always be borne in mind! When man began to mine and work with metals and minerals, to melt these and mould them, he then began to experience the beginnings of industrial exposure to enhanced radioactivity and in this review we will look at modern examples of such industrial exposures. We will also find that there can be specific critical pathways for exposure, an example of which is the pathway for 210Po which is concentrated on to the surface hairs on tobacco leaves and is then neatly packaged into cigarettes for direct exposure to the lungs via inhalation. Thus smoking 10 cigarettes per day doubles the 2’oPo intake.

It is likely that mortalities caused by technological enhancement of radiation in non-nuclear industries have far exceeded in number those to workers within the nuclear industry: for, as we approach the centenary of the discovery of radioactivity, it must be noted that the first 40 years of that period were marked by considerable misunderstanding and then underestimation of the health effects of radioactivity and by not infre- quent misuse of radioactivity and radiation without the necessary precautions. This early period is best viewed in the context of the early

Technologically enhanced radioactivity: An overview 5

history of the discovery and use of radium, ‘radioactivity’ and ‘radium’ being intimately connected at that time as the names imply. Figure 1 shows a summary of the main developments and events up to the mid- 1930s. By then, in the western world only, around 1.5 kg of radium had been removed from the earth for use in early industries, and the appli- cation of this small amount was known to have killed more than 100 workers. The mortality figure worldwide would be much greater. Figure 1 also indicates the range of early industries which used radium, notably

Fig. 1. A summary of events in the early history of radium and radioactivity (after Williams & Kirchmann, 1990).

6 M. S. Baxter

the luminous paint industry, manufacturing of static eliminators, elec- tronic valves, neutron sources, medical cures for cancer, arthritis, neur- itis, hypertension, polio, almost everything including the manufacture and sale of radium-rich drinking water, bath water, compresses, hair tonics, toothpastes, candy bars and fertilizers. All of this resulted in the deaths of unprotected workers, particularly of dial painters, where the ladies who were licking their paint brushes while applying radium-rich luminous paints onto watches and clock faces fell ill and died with a variety of radiation-related illnesses from ‘radium jaw’ and jaw necrosis to cancer death. In 1928 the International Committee on X-ray and Radium Protection was formed and this was the forerunner of ICRP, the International Commission for Radiological Protection, which is now the worldwide authority on radiation protection of workers and the public. Current knowledge shows that many of these early uses of radioactivity, and indeed the widespread unshielded use of X-radiation, were unwise and even sometimes bizarre.

In the light of the relative youth of this area of science, one question worth asking is whether current knowledge represents some intermediate point on a learning curve or approaches a final state of full understanding. For example, Fig. 2 shows the UN’s estimate of the average natural radiation dose to which members of the public are exposed from naturally occurring radionuclides of the decay series of uranium and thorium. Increases in estimates of the dosimetry of 222Rn have, in particular, contributed to the increase in total dosimetry value by a factor of seven in

1600

1400

1200

1000

800

600

400

200

0

1960 1 1962 1 1970 1 1972 / 1977 _] 1980 j 1982 1 1988 1 1990 j 1993 1 2OOO_j

YEAR

Fig. 2. The changing UNSCEAR estimate of average effective dose rate (/.&~a-‘) to a member of the public from natural decay series radionuclides.

TechnologicalIy enhanced radioactivity: An overview 7

the past 25 years. Will the graph level off on this final plateau or will the general trend of doubling roughly every 10 years continue as knowledge and understanding also increase? While perceived wisdom would probably favour the former, there is certainly a need to keep an open mind, parti- cularly in the case of exposures to enhanced natural radioactivity in non- nuclear industries, the subject of this conference. There is considerable evidence that our knowledge of these exposures still lies in its infancy.

May I therefore propose two themes for the discussions at this confer- ence? The first is a quotation from the latest report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 1993) and is in two parts:

(a) “In general, the data for these [non-nuclear industrial] practices and occupations were not sufficient to enable reliable estimates to be made.”

(b) “In the industrial processes associated with the extraction and processing of earth materials, the hazard from radiation is generally small compared to that from other chemical substances, so radiation is not systematically monitored. The assessment of such exposures is based on sketchy information derivedfrom isolated surveys.”

The second thematic quotation is from Schmitz (1989) and refers to the protection of workers, as follows:

“We have in fact a 2-class society of workers:

(1) One population [nuclear workers] governed by the restrictive stipulations of radiation protection (e.g. they inhale the ‘RED’ alpha particles).

(2) Another population [miners, those exposed to enhanced natural radioactivity] which does not enjoy any individual protection, even if radiation exposure is known to be high (e.g. they inhale the ‘GREEN’ alpha particles).

This is absurd from the physical and radiobiological point of view.”

These interesting quotations summarize the main issues at stake. Are we sufficiently informed about radiation exposures to workers and the public from non-nuclear industries? Is there a need for harmonization of radiation protection of workers between the nuclear and non-nuclear industries? If this meeting can extend our database on the subject and can provide an up- to-date summary of radiological protection in non-nuclear industries, then it will have been a most worthwhile start to what I am sure will become a long series of conferences following this first dedicated event.

In the remainder of this opening overview, may I review some current information, taken particularly from the latest UNSCEAR report (1993) hopefully to provide a foundation for the papers which follow.

8 M. S. Baxter

EXPOSURES FROM NON-NUCLEAR FUELS

When coal is burned, the radioelements become concentrated in the resi- dual ash. Table 1 shows some typical data (Baxter, 1993) for radionuclides in coal and fly-ash. It is clear that enhancement of solid-phase radio- activity from five-fold to two orders of magnitude occurs during combus- tion. In addition, coal burning releases 222Rn from the coal matrix into homes and industrial environments. It has been calculated, in fact, that global coal burning (2800 million tons/year) releases around 9000 tons of thorium and 3600 tons of uranium (including 52 000 lb (24 000 kg) of 235U; Gabbard, 1993). Thus the release of nuclear components from coal combustion far exceeds the consumption of nuclear fuels by the nuclear industry. Gabbard also points out that the nuclear fuel released by burn- ing coal contains one and a half times more energy than the coal itself!

However, in reality, the main exposures resulting from coal burning are generated as a consequence of the various uses of fly-ash in modern indus- tries. These include the manufacture of cements and concretes, the construction of dwellings, the stabilization of road surfaces and its use as inlill material in the manufacture of asphalt and in the use of ash fertilizer. UNSCEAR (1993) estimates the collective dose from external exposure only from the use of coal ash in dwellings to be 50000 man Sv. The total dosimetry of coal-ash use will be very much greater. It is likely also that critical groups of workers and the public are exposed to significant doses from fly-ash usage and disposal. One reason for this and following papers is to describe a study in which, during an aerial gamma-spectrometric survey of the River Danube basin, several urban sites were found where 226Ra and gamma-fluxes were greatly enhanced in association with coal fly-ash dispo- sals. Exposures to the public in highly populated areas were possible via inhalation, external exposure and aquatic pathways (IAEA, 1992; Baxter, 1993). It is not only in coal burning that concentration of radionuclides into ash can occur. Several presentations at this meeting (Hedvall et al., 1996; Holm & Ravila, 1996; Krosshavn et al., 1996; Ravila & Holm, 1996, these proceedings) show that, in the Scandinavian forest industries, major concentrations of Chernobyl-derived radiocaesium and radiostrontium

TABLE 1 Typical Activity (Bq kg-‘) of Fly-ash Compared with Coal

4OK 238 (J 226Ra 2roPb 2’oP0 232Th 228 Th 228Ra

Coal 50 20 20 20 20 20 20 20 Fly-ash 265 200 240 930 1700 70 110 130

Technologically enhanced radioactivity: An overview 9

occur. When wood or peat is used as biofuel, significant dose rates arise from radionuclide concentrations in the ash deposits, while, in wood pulp manufacture, anthropogenic radionuclides are found to concentrate in the process liquors and waste products.

Another important technological enhancement process occurs in the oil and gas extraction industries. Here, scales and sludges which are essen- tially co-precipitates of calcium and barium carbonates and sulphates and which carry radium, can show 226Ra concentrations of up to several kBq g-’ with corresponding levels also of radon daughters in sludges. The precipitates affect piping, sludges, pits, filters, brine disposal, injection wells and lead to enhanced radioactivity in pipe cleaning yards and their environments. Films, coatings or platings formed during natural gas production and processing contain high concentrations of 222Rn, these being found mainly at gas well heads, transport piping, headers, treater units and pumps, with concentrations of 222Rn up to 55 Bq litre-’ in the natural gas at the wellhead. Recent work in the Netherlands (Heling & Van der Steen, 1994) has shown that, in produced water at gas and oil platforms in the North Sea, radium isotopes are discharged at quite significant rates, e.g. up to 20GBq year-’ each of 228Ra and 226Ra, with radionuclide concentrations up to 240 Bq litreel. The same authors have also published a radiological assessment of the consequences of radio- nuclide disposals, with particular reference to the marine environment. The model, which is applicable also to the discharges from other indus- tries, e.g. phosphate waste releases, considers dispersion of each radio- nuclide, its uptake into sediment, transfer into seafoods and subsequent ingestion; in addition, re-suspension of contaminated particles as aerosols and inhalation by beach occupants are considered; the use of contami- nated sediment for land-fill for housing is included, this pathway resulting both in external gamma exposure and enhanced inhalation of 222Rn; and, finally, recreational exposure during boating, swimming and beach occu- pancy is considered. For the oil industry, the dose estimates show that critical group exposures are dominated by 210Pb, 226Ra and 210Po. However, they have significant contributions, worthy of calculation, from the entire decay series. In our later paper (McDonald et al., 1996) the Bateman equations for series decay have been adapted for the distur- bances to decay and ingrowth effects caused by radionuclide removals and exchanges with particulate and biological components of the marine environment.

Table 2 shows a summary of the collective doses for unit energy production by non-nuclear sources (UNSCEAR, 1993) and provides a relative ranking of the importance of each energy source to global dose delivery. The equivalent figure for nuclear energy production, including

10 M. S. Baxter

TABLE 2 Estimates of Collective Effective Dose per Unit Electrical Energy Generated by Non-

nuclear Sources (UNSCEAR, 1993)

Source Normalized collective effective dose (man Sv (GWa)-‘)

Coal Oil

Natural gas Geothermal

Peat

20 0.5 0.03 2 2

the entire fuel cycle, is around 200 man Sv (GW year))‘. It is likely that the dose estimates shown may be increased in the near-future as recent information suggests that Chinese and Eastern European lignites are considerably more radioactive than those previously used in the average dose calculations. Nor does Table 2 give any information on critical group exposures which may result, for example, from fly-ash inhalation, oil-scale removal and disposal, 222Rn inhalation in natural gas or geothermal energy production or, for that matter, radiocaesium inhalation in fly-ash following peat or wood combustion.

EXPOSURES RESULTING FROM MINERAL MINING AND PROCESSING INDUSTRIES

Many heavy minerals contain rather high concentrations of natural radioactivity. Table 3 shows some typical radionuclide concentrations in

TABLE 3 Typical Concentrations of 232Th and 238U in Heavy Mineral Sands in Australia

(UNSCEAR, 1993)

Mineral ‘j2Th concentration 238U concentration

(Bq kg-‘) (4 kg-‘)

Ore 60-200 40 Heavy mineral concentrate 1000-1300 c 100

Ilmenite 600-6000 -=z 10&400 Leucoxene 1000-9000 250-600

Rutile < 60&4000 < 100-250 Zircon 200&3000 20&400

Monazite 60000&900000 10000-40000 Xenotime 180000 50000

Average soil and rock 40 40

Technologically enhanced radioactivity: An overview 11

heavy mineral sands (UNSCEAR, 1993). Bearing in mind that substances are traditionally considered radioactive above the range of a few hundred Becquerels per kilogram for solids, depending on context and usage, Table 3 shows that many natural minerals fall in that category with concentra- tions many orders of magnitude above the average for soils and rocks on earth. These minerals, which are oxides, silicates or phosphates of transi- tion or rare earth metals, are used in a vast range of industries, including use as pigments in the paper, plastics, cosmetics and ceramics industries, application in the aircraft industry as structural materials and in the manufacture of catalysts, superconductors, ceramics, alloys, magnets, paints and electronics in general. A recent survey around a site in Australia, where heavy minerals are mined and milled, showed that public exposures in excess of 1 mSv year-’ were possible, mainly from external exposure from mineral spillage, and around 0.25 mSv year-’ from inhala- tion of dust, That considerable enhancements of gamma irradiation can result from these industrial minerals is obvious, given that natural dose rates over geological deposits can cause extreme absorbed dose rates, ranging from < 100 nGy hh’ over phosphates in Florida to ,<4000nGy h-’ over monazite in Brazil, Saudi Arabia, and India, to < 12 000 nGy hh’ over carbonatite in Kenya, d 30 000 nGy h- ’ over travertine in Iran, to d 100 000 nGy h-’ over recently notified deposits of uraniferous deposits in Sweden (cf. the population-weighted global aver- age of 57 nGy h-’ (UNSCEAR, 1993).

The building industry also provides a vector by which radioactive minerals can be incorporated into dwellings resulting in enhanced dose rates. For example, the observed dose rate in air inside homes constructed of alum shale concrete can be as high as 670 nGy h-i, with smaller though significant enhancements also in dwellings constructed of materials such as gypsum, phosphogypsum, coal-ash aggregate and granite blocks. The processing of ores to extract metals results also in selective extraction of radionuclides. Since this meeting is being held in Southeast Asia, it is perhaps particularly relevant to recah the recent controversy regarding the Bukit Merah rare earth plant in Malaysia, which processes monazite to produce yttrium. This industrial site was claimed to have induced child- hood leukaemia at 42 times the Malaysian average rate due to dumping of radioactive ‘wet-cake’, largely comprising thorium hydroxide, on open land, with no precautions against exposures amongst workers or the public. A further reason for my own participation here is an involvement in a related study of a UK ore smelter which is described hereafter (Baxter et al., 1996). Here, considering *“PO alone, an annual turnover of ~10” Bq was found to occur with -50% in three feed materials and with some intermediates having *i”Po activity concentrations of -lo3 Bq gg’.

12 M. S. Baxter

An absence of secular equilibrium in feed materials implied losses in the supply industries. There have been relatively few studies of radiation protection in ore processing industries. One notable exception (NRPB, 1984) showed that workers could, under pessimistic assumptions, receive doses of 5 mSv year-’ by inhaling dust from feed materials containing as little as O-3 or 1 Bq gg’ of, respectively, 232Th and 238U, assuming secular equilibrium within each decay series. As we have seen, such activity concentrations are commonplace in nature and thus are likely to be commonplace also in industries which process natural ores and minerals.

The mineral industry, which is currently believed to be radiologically the most significant, involves the mining, milling, processing and disposal of phosphates. The products which are most commonly involved are fertilizers, detergents and acids, and environmental exposures occur both from the usage and from the wastes, particularly of phosphogypsum in building materials, backfill and road-base materials, in mine reclamation and in fertilizers. Burnett and Hull (1996) show that the problem of disposal of radioactive phosphogypsum waste is one of enormous proportions, the waste mountain in Florida being one of relatively few man-made constructions visible by naked eye from outer space. Table 4 shows a summary of the phosphate dosimetry according to UNSCEAR (1993), in particular emphasising the importance of the use of phospho- gypsum in concrete, cement and plaster construction materials. This is major global dosimetry. Although the average annual effective dose is only -lO@v, individual critical group exposures can be significant. The disposal of phosphate wastes into the marine environment is a common occurrence and we (McDonald et al., 1996) have observed increases in *l’Po concentrations in seafoods from the Irish Sea in the UK resulting from discharges from a phosphate-processing factory near Whitehaven. The critical group doses can be in the mSv year-’ range, a finding which

TABLE 4 Phosphate Dosimetry (UNSCEAR, 1993)

Collective effective doses:

60 man Sv 1 year’s discharge to atmosphere from all phosphate industrial facilities

10 000 man Sv 1 year’s use of fertilizers

100 000 man Sv External radiation from 1 year’s use of phosphogypsum in the building industry

200 000 man Sv Inhalation of radon progeny following 1 year’s use of phosphogypsum in the building industry

Per capita annual effective dose -10 $5~

Technologically enhanced radioactivity: An overview! 13

agrees with others reported elsewhere in Europe, particularly in the Netherlands (Koster, 1989; Koster et al., 1992; Timmermans & van der Steen, 1996). Incidentally, McDonald et al. (1996) also found marine enhancements of natural radioactivity resulting from disposals of coal mine spoil in northeast England and of oil-scale wastes near Aberdeen in northeast Scotland.

Since I represent a UN Marine Laboratory, let me digress briefly to mention that fish products normally contain the highest concentrations of radionuclides amongst foodstuffs in general, with concentrations of 210Po typically around 2 Bq kg- ’ and relative enhancements also of 226Ra and 210Pb (UNSCEAR, 1993). That marine organisms are effective in concen- trating natural radionuclides, particularly *l’Po, from sea water is shown elegantly by a recent IAEA-MEL Coordinated Research Programme, the results of which will be published as an IAEA Technical Document during 1995. This study showed that, in each of the FAO fishing areas, the collec- tive dose from 2’oPo delivered by consumption of fish is much greater, typically by two to three orders of magnitude, than the dose from the principal man-made radionuclide, 137Cs. The food industry, however, also includes some outstanding examples of enhanced natural radioactivity in terrestrial foodstuffs including dairy products from Brazil, reindeer meat from Sweden, cereals, vegetables, tubers and fruits from the monazite regions of India, containing up to 30Bq kg-’ of nuclides such as 228Th, 226Ra, 210Pb and 2*oPo (UNSCEAR, 1993). Drinking waters can also contain surprisingly high concentrations of enhanced natural radioactivity, particularly French, German and Portuguese bottled mineral waters (226Ra concentrations -3 Bq litre-‘) and Finnish ground waters which contain 2’oPb concentrations up to 10.2 Bq litre-’ (UNSCEAR, 1993).

The radioactivity in geological materials is of course a potential problem to those who extract the ores and minerals in the mining industries. Again according to UNSCEAR (1993) the average annual effective dose for coal miners is 0.2mSv, while for miners of other non-uranium metals and minerals the average dose rate is 4.8 mSv year-‘. Notable amongst the data for average annual doses to miners are those for the lead/zinc (13 mSv), tungsten (13 mSv), and, once again, phosphate (20 mSv) industries. Table 5 summarizes the UNSCEAR (1993) data for occupational exposures to natural radiation. Here we see that the main collective dose is delivered to coal miners, although the highest average annual dose relates to miners of other minerals. Also shown is the relatively large dosimetry delivered to relatively few workers in the air transport industry. The enhanced cosmic ray dose at high altitude results for example in average effective dose rates of 14&Sv h-’ at 15 km altitude. With maximum values of around 55 @v h-l, these dose rates compare to a ground level average of

14 M. S. Baxter

TABLE 5 Summary of Occupational Exposures to Natural Radiation (UNSCEAR, 1993)

Occupation or practice

Number of workers

Worldwide annual collective effective

dose (man Sv)

Average annual effective dose

(mSv)

Coal mining 3900 3400 0.9 Other mining 700 4100 6 Aircrew 250 800 3 Other 300 < 300 <l

Total 5200 8600 1.7

380 j&v year-‘. This latter effect of higher dose at higher altitude is also relevant to the industrial concentrations of populations in high-altitude cities. For example, the annual effective dose at La Paz in Bolivia is -2mSv, around eight times the sea level dose rate (UNSCEAR, 1993). While this dose enhancement may be peripheral to the main theme here, it is nevertheless true that people moving from rural regions to high altitude urban areas in order to obtain gainful employment, must then experience enhanced radiation exposure from natural sources.

Table 6 shows the annual effective dose to an average member of the public resulting from the industries discussed thus far (UNSCEAR, 1993). It shows the relative importance of the industries as mentioned, with the phosphate industry dominating, followed by the use of fly-ash in building

TABLE 6 Estimates of Annual per Capita Effective Doses Resulting from the Extraction and

Processing of Earth Materials (UNSCEAR, 1993)

Source Annual per capita effective dose (~SV)

Coal Mining 0~0001-0~002 Electrical energy production 2 Domestic use 04-8 Use of fuel ash 5

Other non-nuclear sources of electrical energy production Oil 0.01 Natural gas 0.001 Geothermal 0.001

Exploitation of phosphate rock Industrial operations 0.04 Fertilizers 2 By-products and wastes 10

Technologically enhanced radioactivity: An overview 15

materials and then by the burning of coal both industrially and domes- tically for energy production.

We should also perhaps mention exposures resulting from medical uses of radiation in which radiographers, radiotherapists, practitioners of nuclear medicine and dentists receive quite significant doses (< 1 mSv year-‘). Similarly, industrial radiographers, producers and distributors of isotopes and scientists in tertiary education, etc., also receive average individual doses of mSv year-’ magnitude (UNSCEAR, 1993). In the industrial context, accidents involving industrial sources have occasionally led to major exposures, notably the accidents in Ciudad Juarez, Mexico, in 1983, in Mohammedia, Morocco, in 1984, and Goiana, Brazil, in 1987, in each of which large radiation sources found their way from non-nuclear industries into the domestic environment, resulting in large individual overexposures and a number of deaths (UNSCEAR, 1993).

CONCLUSIONS

Let me return to the themes proposed early in this presentation, namely that insufficient data are available to enable reliable estimates of dose in the non-nuclear industries, i.e. that the information base is ‘sketchy’. Also, in terms of exposures to industrial workers, there is a two-tier system of radiation protection. In the latter context, we will, I am sure, hear at this meeting that several countries in the West have already taken steps to apply similar radiation protection procedures and control practices to non-nuclear industries as apply already in the nuclear industry. This may mean that, in the medium-term future, we will have a two-tier society of workers based on geography, with high standards of protection generally in the developed countries and a continuation of the past system of non- protection of non-nuclear workers in developing countries.

Let me digress briefly to mention terminology. In certain countries, this general phenomenon is described by the word NORM (Naturally Occurring Radioactive Material). The use of NORM to describe the artificial industrial enhancement of radioactivity is a clearly misleading and inaccurate one. It implies that the concentrations of radioactivity are exactly as found in nature. Generally speaking, this is not the case. We are concerned here with the technological enhancement of radioactivity and hence some other abbreviation, if one is needed at all, should be used. It would, for example, be more accurate to use the analogous term TERM (Technologically Enhanced Radioactive Material) to describe the artificially enriched radioactive substances produced in these processes and industries.

In this meeting and in the spirit of Schmitz (1989) let us therefore be

16 M. S. Baxter

red/green colour-blind, trying to eliminate the kind of logic which leads to different radiological protection practices and standards in different industries. Let us also try to fill in some of the information gaps which are internationally recognised to exist and which prevent the full picture being other than ‘sketchy’ at the present time. Finally, let us consider the following questions: is there an imbalance in the understanding and control of radioactivity emissions from non-nuclear versus nuclear indus- tries? Is there a corresponding imbalance in the required safety standards associated with each type of industry? Also, are the financial responsi- bilities for minimizing radioactivity emissions similar in each case? Is there a need for harmonization of assessment and control practices? In addition, is there a need for more realistic quantification of all the environmental and health detriments from non-nuclear industries, including the global, environmental, radiological and toxicological aspects?

This is the first meeting on an extremely interesting and potentially important subject. I am sure that it will be looked back upon as a landmark event. We are almost certainly at some intermediate stage of understanding the topic in question. I am sure that the contributions which follow will address a major and socially important gap in knowledge and I share with you the pleasure of working together at this dedicated meeting in a concerted effort to improve our knowledge base and our understanding.

ACKNOWLEDGEMENTS

The IAEA Marine Environment Laboratory operates under a bipartite agreement between the International Atomic Energy and the Government of the Principality of Monaco.

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Technologically enhanced radioactivity: An overview 17

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