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The main aim of these works was to review the different methods applied for mitigation of potential radiation detriment caused by presence of TENORM at workplaces and preventive or corrective actions focused on improving the current state of areas polluted by waste and effluents from plants or factories affected by TENORM.
In order to receive an overview about all relevant TENORM industries each participant was obliged to prepare an overview of mitigation methods and/or remedial actions applied in particular branches of industry:
Poland occupational risk in underground mines and environmental impact of radium bearing waters;
Czech Republic - TIP industry;
Hungary - CCPs (slag and ash), bauxite processing, uranium bearing waters;
Slovenia - CCPs external radiation, zirconium sand processing;
Romania - bauxite processing (alumina production);
Belgium - phosphates industry;
Germany - water works.
Countermeasures against detrimental effects caused by enhanced natural radioactivity presented can be generally divided into two groups: passive and active measures.
Passive methods generally consist in diminishing of radiation effects, whereas active ones are based on a possibility to influence the radiation source. Interventions in frame of active methods might reduce harmfulness of existing sources or change exposure pathways, while the passive ones are going to result in widely comprehended reduction of the number of individuals exposed. The countermeasures applied for reduction or elimination of TENORMs negative effects might be presented as a function of their effectiveness and frequency of occurrence.
The kind and number of TENORM industries, the amount of material, residuals and waste and, the level and variability of specific activities differ considerably between the participating countries as well as between the factories or sites of one and the same branch.
From the initially selected 43 industrial branches where TENORM could occur 31 branches or processes have been identified in at least one of the participating countries. Beside of such industries which never existed in the participating counties, especially some kind of ore mining, that is mainly the result of decommissioning of older factories, decreasing industrial capacity, changes in the economic structure, implementation of advanced low or no waste technologies and/or the use of imported intermediate products instead of raw materials.
The last two arguments concern mainly the European phosphate fertilizer industry. Furthermore, for two of these 31 branches no TENORM according to the above-mentioned definition were identified. That concerns the steel production and the oil refinery. In case of metal melting for secondary melting also no TENORM have been identified.
The greatest amount of residuals results from mining and combustion of coal in all countries. Nevertheless, from the heaped up or re-used waste rock material and fly ash only a minor part contains naturally occurring radionuclides with enhanced concentrations. On the other hand, coal mining may lead to higher contaminated residues as a consequence of pit water treatment and of contaminated river sediments and banks if the pit water is discharged without treatment.
Furthermore, high specific activities of more than 10,000Bq/kg of naturally occurring radionuclides were identified for oil and gas exploitation (scales), iron melting (blast furnace sludge and sinter dust scales), titanium pigment industry (ash), processing of mineral sands (raw materials), niobium and tantalum manufacture (raw materials, solid waste), primary zinc, copper and lead melting (dust precipitates) and drinking water and mineral water processing (sludge), but in most cases of comparably small amounts.
The report RP 107 established reference levels for regulatory control of workplaces where materials are processed, which contain enhanced levels of natural occurring radionuclides. The reference levels in RP 107 which are corresponding to specified dose levels were derived from normal assumptions and unlikely assumptions defined for two different exposure scenarios of each exposure pathway.
In contrast, the dose calculations carried out by the contractors of the TENORMHARM project are based upon measurements of irradiation and radionuclide concentration at a working place or an other location of interest. The dose calculation was carried out according to the German methodology described in the Guideline for calculation of dose resulting from mining related legacies.
It was demonstrated that the applicability of reference levels for regulatory control of workplaces given in RP 107 seems to be limited because the considered scenarios used for deriving reference levels do not reflect sufficiently the recent work conditions. Moreover, any scenarios described by the contractors have no applicable counterparts in RP 107.
According to the modern work conditions and the statutory requirements of measures to prevent an ingestion of contaminated dust this exposure pathway can be neglected in most cases. The same concerns the contamination of skin.
Compilation and evaluation of exposure to workers and members of the public by type of industry in countries participating in the TENORMHARM project was carried out by ranking of the impact of residues appearing at certain branches of industry in terms of the potential or real radiation risk. In order to prepare the ranking scheme, a simply algorithm of classification was agreed among the members of the consortium.
As the national reports demonstrate the possible levels of dose, the amount of material, residuals and waste, number of the members of the public of concern and, the level and variability of specific activities differ considerably between the participating countries as well as between single plants of each special TENORM branch. The greatest amount of residuals results from mining and combustion of coal in all countries.
On the other hand, from the heaped up or re-used waste rock material and hard coal as well as lignite combustion products (CCP) only a minor part contains naturally occurring radionuclides with enhanced concentrations (> 200Bq/kg) but the total number of potentially influenced person is very large due to common use of such waste, i.e. as construction materials.
Nevertheless, mining and milling activities may lead to higher contaminated residues as a consequence of discharging waters with enhanced concentration of radium isotopes or sludge from such water treatment plants. The most important is the first situation because such water can cause uncontrolled contamination of ponds or rivers banks. Additionally the contamination can be spread out by flood so that the number of affected persons is difficult to asses.
In comparison, high specific activities of naturally occurring radionuclides in smaller amounts were identified for oil and gas exploitation, ore melting and processing of mineral sands. Such waste materials are not very common and the range of their occurrence is usually limited to the territory of a plant where they have been processed, i.e. only workers could be exposed.
According to the investigated types of TENORM main attention was paid to such which are heaped up or dumped into ponds outside of factory rooms and warehouses.
Guidance is given for the design and implementation of environmental monitoring and emission control for heaped-up and dumped TENORM, as waste rock materials, tailings and sludge based upon German experiences on monitoring of former uranium mining and milling sites.
Furthermore, the Polish monitoring program applied in hard coal mining is explained.
As part of WP3 dealing with harmonisation of legislation between old and new EU member states as well as the candidate country Romania a questionnaire sent around by the EU at the end of 2000 to collect information about the legal measures for provisions of Title VII of the Directive 96/29/Euratom was used.
Within the Basic Safety Standards Directive activities involving naturally occurring radionuclides likely to result in a significant increase in exposure of workers or members of the public, were defined separately as work activities.
As the new states did only join the EU in May 2004, it must be clear that the implementation of Title VII is a not yet finalised process in these countries. Even in some of the old member states the approach as to TENORM in still a process in evolution.
To give the participants the opportunity to take changes into account the questionnaire distributed originally in the spring of 2003 was sent around again for updating in the summer of 2004. In this way the answers are representative for the situation at the end of 2004.
Through the questions, remarks and comments obtained in course of this WP, it became clear that some of the questions could be interpreted in a different way and is in some way a little bit misleading (for example the questions dealing with Art. 41 of Title VII).
It should also be kept in mind that about all of the participants are research institutes and not regulators. Due to the complexity of the matter, it may well be that for some topics the researchers view and interpretation, as reported here, deviates in some (but not fundamental) way from the regulators one.
It must be stated that there is an urgent need to support the "new" member states and candidate country in implementing the Directive 96/29 and subordinated regulations into national regulations to reach harmonisation within EU.
Each participant selected one or two industrial branches of any relevance within the concerning country and prepared an overview of the applied methods for re-use or disposal and, if appropriate to indicate the best options.
As it was proven during previous tasks in majority investigated national cases the efforts are focused on comprehensive evaluation of TENORM and therefore it is not possible to estimate the meaningfulness of TENORM re-use or even the correctness of its disposal. In majority cases the TENORM treatment has a temporary nature and is focused on keeping it in natural state and minimise detrimental effects rather than reprocessing. Only in case of CCP and waste rock materials there are common use for construction materials production. In spite of that for this purpose the requirement enclosed in Radiation Protection 112 were applied.
Few reports describes the national approach to the re-use or the final treatment of TENORM. They deal generally with TENORM treatment (Slovenia, Czech Republic) or concern specific situation in relation to TENORM occurrence (Poland). Basing on data that had been collected during previous tasks realization a list of all substances that occur in different kind of industry and can be classified as NORM or TENORM was prepared. For every one the pieces of information concerning the actual practice of storage, recommendation and re-use were compiled. It can be shown that in different countries the same kind of waste occurred but the treatment differed each other.
Furthermore, some methods for re-use or disposal, which are radiologically safe, are not applicable due to restrictions of other regulations, e.g. on soil and water protection and common waste management. That was demonstrated for re-use or disposal of residues from oil and gas extraction in Germany.
The TENORM branches which are of any relevance for each participating countries were selected for dose assessments.
Germany: The highest occupational exposure occurs in oil and gas exploitation, i.e external exposure due to working at drilling platforms and at pipe storage sites. The highest dose due to inhalation of dust was found for removal of scales by sandblasting. Therefore this method is now prohibited and replaced by high pressure water jet method.
The highest exposure to members of the public result from stay at river banks contaminated by untreated discharge of pit water from hard coal mines.
Czech Republic: Within the titanium pigment industry the highest occupational exposure result from pre-processing of limonite ore via inhalation of dust. The improvement of work conditions lead to a significant decrease of exposure. The local population is not affected by this industry.
Hungary and Slovenia: The dose to members of the public resulting from coal combustion is lower than 0.3mSv/yr
Romania: The dose to members of the public in case of staying at red sludge dumps was calculated. The highest dose results from inhalation of radon and progenies. Nevertheless, the exposure is overestimated due to the use of Rn 222 concentrations measured 10 cm above ground.
Belgium: The external exposure resulting from phosphogypsum stockpiles was calculated for "likely" and "unlikely" assumptions.
Poland: The dose to miners in underground hard coal mines were calculated. While for the "nominal" scenario (1,800h/yr) the external dose dominates for the "real" scenario the radon inhalation gives the highest contribution to the total dose.
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