4    CONCLUSIONS

  4.1    Adequacy of Monitoring

    The Task Force concludes that:

    (1)    Monitoring meets the needs of the relevant atomic energy acts in the United States and Canada but is not designed to look at environmental cycling of radionuclides.

    (2)    Quality Assurance Protocols are also designed for compliance monitoring. Therefore, it is not possible to tell if nuclear plant monitoring is satisfactory to assure meeting the goals and objectives of the Great Lakes Water Quality Agreement.

Discussions

    The information base used to assemble the inventories, notably the emissions data from nuclear facilities, and the monitoring data off-site of the facility but keyed to activities of the facility, has many problems. The Task Force reviewed the actual monitoring protocols ( i.e. , directives, instrumentation, sampling plans, chemical analysis techniques, station and monitoring site locations, quality assurance considerations, data reporting and statistical analysis procedures), and found the following:

    (A)    All monitoring has as its primary goal to show that a given nuclear facility complies with the health, safety, and environmental requirements of its facility license. In turn, the health, safety, and environmental requirements in the license are dictated by the atomic energy legislation of each country. Thus, the Task Force concluded that the current state of monitoring is that of compliance.

    (B)    The atomic energy legislation of each country prescribes a maximum annual allowable human exposure to radiation as the basis for setting the environmental monitoring requirements for each individual radionuclide. The use of dose assessment models translate this exposure criterion into allowable discharges of specific radionuclides and types of energy.

    (C)    The dose assessment models used to derive the allowable discharges have a very limited relationship to the cycling of radionuclides for development of an inventory. The models make assumptions about the distribution of the activity of a given radionuclide in different environmental compartments and the fraction of that radionuclide's activity which is taken up by biota and assimilated and retained as opposed to taken up and then released, excreted, or otherwise removed. The models also make specific assumptions about the transfer of radioactivity from retained radionuclides in other biological compartments and the movements of the radionuclides through various foodwebs. This includes direct uptake by humans through drinking water or through intermediate uptake and bioaccumulation through food species.

    (D)    When monitoring environmental media, it is a particular characteristic of radionuclide measurements that the lower limit of detection for a given sample will depend on the amount of time lapsed between collection and analysis. This arises because the radioactivity in the sample continues to decay after sample collection, and all measured activities must be corrected back to the time of collection. Thus, the reported lower limits of detection may vary considerably from one laboratory to another, or even for measurements carried out in the same laboratory at different times after collection. For this reason it is not practical to use reported lower limits of detection in order to derive an upper bound for the radionuclide inventories in the Great Lakes, or in any environmental compartment within the lakes.

  4.2    Need for a Reassessment of Environmental Monitoring of Nuclear Facilities to Support the Great Lakes Water Quality Agreement

    The comments on monitoring in the previous four items are generic and do address specific data problems associated with individual facilities in each country. These comments led the Task Force to conclude that:

    (3)    There is a strong need for a comprehensive review of all monitoring activities at nuclear facilities with a view toward making the monitoring more accommodating to the needs of the Great Lakes Water Quality Agreement.

    (4)    Since there are policy and fiscal implications to any likely expansion or adjustment of the monitoring efforts, the Task Force calls upon the relevant atomic energy and environmental agencies in each country to explore in great detail the kinds of monitoring needed and the changes to the current protocols.

  4.3    Reporting

The Task Force concludes that:

    (5)    There are significant differences in the scope of data reporting and analysis of United States and Canadian nuclear power plant emissions.

    (6)    The monitoring for toxic chemicals used in large quantities at nuclear power plants needs to be included in analyses of their impact on the Great Lakes ecosystem

    (7)    The monitoring of radionuclides does not include the identification of radioactive forms of toxic chemicals.

    (8)    The details of United States data reporting are greater and more helpful for the purpose of ecosystem impact analysis than is Canadian reporting, but the United States data come in mixed formats, which make them difficult to organize.

    (9)    Facilities in the United States have historically aggregated their data on an annual basis, but that the contract to continue this aggregation task has apparently been discontinued as a cost savings measure.

    (10)    The current biological monitoring and reporting is neither consistent nor adequate for lakewide assessments.

    (11)    Developing inventories for specific isotopes in biological compartments was a difficult task because no common reporting format for production/presentation of biological data is used.

Discussions

    Conclusions 5 through 11 describe problems associated with using the specific data from individual nuclear facilities and associated monitoring sites. The conclusions address the scope of data collections, the completeness of such data collections from specific sites and facilities, the methods of reporting and aggregation of the data, and the problems of handling data from variable formats. In addressing these specific data issues, the Task Force noted the following important considerations:

    (A)    Since all of the Canadian nuclear power plant facilities belong to one corporate entity, the Canadian data are quite uniform in their scope, reporting, and formats. The United States nuclear power plant facilities, however, belong to some 15 different corporate entities. Thus, while the United States facilities report data that meet the requirements set by the (US) Nuclear Regulatory Commission, these data often vary in scope, reporting, and formats.

    (B)    To bring some semblance of order to the data from United States nuclear power plants, the Nuclear Regulatory Commission had previously contracted with the Brookhaven National Laboratories to produce an annual document, which assembled in a standardized format the emissions data from United States nuclear power plants. These reports often appeared 3 years after the individual facilities reported their emissions for a given year and usually reflected the varying timetables and lag times in the submissions of data from the United States facilities. The termination of the Brookhaven contract in 1996 without a new contractual effort represents a serious reporting setback for those groups interested in the radionuclide emissions from United States nuclear power facilities.

    (C)    The Task Force noted that the United States reporting tends to include a far greater number of radionuclides than the Canadian reporting, although the Task Force could not always judge whether the more extensive reporting by United States sources is more comprehensive and useful than the Canadian reporting. The United States data often report radionuclides at extremely low levels, basically limits of detection. The uncertainties in the reported data may call into question the information value of reporting selected radionuclides in certain emissions at levels of detection. On the other hand, the aggregated reporting of these radionuclides at trace levels does reveal much about the performance of the nuclear reactors and allows for a better understanding of the relationship between a particular reactor technology and the generation of its nuclear waste products.

    (D)    Biological data have multiple problems, ranging from sample descriptions to variable lower limits of the levels of detection of radionuclides. The latter problem has particularly troubled the Task Force, because for many radionuclides the lower limit changes with every sample even when the methodology and instrumentation do not change. This rather curious situation arises because of the need to back calculate and correct radionuclide data to the original time of sampling. Radioactivity continues to decay in a sample after collection and through the period of storage, analysis, and reporting. To place all measurements on a common basis, the radionuclide levels must be corrected to those at the time of sample collection.

    (E)    The large-scale use of nonradioactive toxic chemicals at nuclear power plants is often overlooked in establishing toxic substances inventories and monitoring activities. Among the chemical problems are those related to weed control on roadways and fence areas in a facility and at its perimeter, calling for considerable use of herbicides and pesticides. Facilities with cooling towers require the use of antifouling agents, water softening agents, and a variety chemicals to maintain heat transfer surfaces at their highest heat exchange capacities. The corrosion and fouling of piping and cooling system components, including water intakes, has led to widespread use of anti-corrosion and fouling-control agents. The problems of the zebra mussel has led to increased use of chlorine as a decontaminating agent. How these chemicals behave in contact with radioactivity is not assessed in any of the monitoring work.

  4.4    Harmonization of Monitoring and Data Reporting

    The Task Force concludes that:

    (12)    There is a need to harmonize the approaches used in the United States and Canada with respect to the scope of monitoring, the radionuclides reported, and the reporting of biological data. International cooperation among the nuclear agencies of both countries would accomplish much of this harmonization.

  4.5    Biological Transfer Factors for Lake Systems

    The Task Force concludes that:

    (13)    There is a special issue of reporting nuclear data, which applies specifically to the Great Lakes and has the implication of rendering incorrect some dose-assessment factors used in establishing the transfer of radionuclides from biota to humans in the region of interest. The issue relates to the transfer factors which estimate uptake of radionuclides in biota. These transfer factors traditionally have been derived from work done in rivers and oceans, rather than in freshwater lakes. The Task Force is concerned that the factors derived from riverine and oceanic systems are inappropriate for use in the Great Lakes.

Discussion

    In developing the inventory for radionuclides, the Task Force noted that the bioaccumulation, biomagnification, and transfer factors used to describe the cycling of radionuclides and their transfer along exposure pathways to biota, including humans, came from the long history of work done in the marine, estuarine, and river environments. This work stemmed from interests in the deposition of radionuclides in the oceans and the transport of radionuclides down rivers and estuaries from discharges to the oceans. The comparable studies for lakes were virtually non-existent. Yet for the Great Lakes, the need for transfer factors that describe lake environments is critical.

    To what extent can one use riverine, estuarine, or oceanic data to infer lake situations for the cycling and transfer of radionuclides in environmental compartments? Where no data exist, it is the obvious approach.

    But why bother to use marine data when lake data exist that can be used to develop the appropriate factors? The Task Force undertook such analysis after discovering the nuclear sciences literature was not extensive in its coverage of lake situations.

    To those persons who believe that the oceanic work, excellent as it was, should be used for the Great Lakes without confirmation, the Task Force cites two examples: radionuclides of silver, specifically 110,110m Ag, and radionuclides of lanthanide elements (rare earths). These radionuclides appear in the effluents of nuclear power plants from the Great Lakes.

    Silver, in the presence of chloride (the main anionic constituent of estuaries and oceans) forms silver chloride (AgCl), a compound with such a low water solubility in water that it is a basis for the quantitative analysis of silver. To reverse the solubility requires a large quantity of either ammonia or cyanide ion, such levels in environment being toxic in their own right. Because of nitrogen limitations of marine and estuarine environments, ammonia would not be present in these environments unless a specific pollutant source were present or an unusual algal species dominated plankton production. In lakes and rivers, however, where chloride is low and nitrogen is rarely limited, the presence of the silver radionuclides in soluble ionic form is almost a given. Only soluble silver is subject to biouptake, and biouptake factors for silver in freshwater systems are as high as 100,000. However, factors for silver do not exist for freshwater biota, and thus the marine factors are the ones in use.

    Rare earth elements (the lanthanides) have unusual biological uptake. Freshwater organisms can often selectively accumulate these elements, and except for yttrium, cerium, and lanthanum, and in a few instances europium, usually only the even atomic numbered elements accumulate in freshwater biota. Thus, it is not correct to assume that all lanthanides accumulate and to use the marine factors, which rarely discriminate among lanthanides, but rather use cerium and lanthanum as surrogates for all of the elements in this group.

  4.6    Radionuclides of Concern

    Based on the Task Force's studies, it concludes that:

    (14)    There are radionuclides that merit separate studies and further reporting because of the patterns of use and discharge; physical, chemical, and biological properties; and the special monitoring needs of lakes as opposed to estuaries, oceans, and rivers (these include tritium, carbon-14, iodine-129, isotopes of plutonium, and radium-226).

    (15)    There are other radionuclides that could be a potential concern in special situations: technetium 99, -99m; phosphorus-32; chromium-51; cesium-134, -137; cerium-141, -144; strontium-89, -90; iodine-125, -131; and cobalt-60.

Discussions

    The radionuclides listed in conclusion 14 are those which have exceptionally long half-lives, arise from both natural (cosmogenic and primordial) sources and some aspect of the nuclear fuel cycle, and present long-term toxicological and ecological problems. Except for 14 C and 129 I, the isotopes are routinely monitored in the Great Lakes.

    The isotopes listed in conclusion 15 occur often in the discharges of sources other than nuclear power plants as well as in some cases in various components of the nuclear fuel cycle. Under conditions of large-scale emission or abundance, they merit special monitoring studies.