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Journal of Environmental Radioactivity 138 (2014) 303e307

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Journal of Environmental Radioactivity

journal homepage: www.elsevier .com/locate/ jenvrad

Environmental radionuclide monitoring of Canadian harbours:a decade of analyses in support of due diligence activities bythe Royal Canadian Navy

David G. Kelly*, Kristine M. Mattson, Curtis McDonald, Kathy S. Nielsen, Ron D. WeirDepartment of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000 Stn Forces, Kingston, ON K7K 7B4, Canada

a r t i c l e i n f o

Article history:Received 15 August 2013Received in revised form13 May 2014Accepted 29 May 2014Available online 20 June 2014

Keywords:Nuclear vessel monitoringBioaccumulationIodine-131

* Corresponding author. Tel.: þ1 613 541 6000.E-mail address: david.kelly@rmc.ca (D.G. Kelly).

http://dx.doi.org/10.1016/j.jenvrad.2014.05.0230265-931X/Crown Copyright © 2014 Published by Els

a b s t r a c t

The Royal Canadian Navy has conducted a comprehensive programme of safety, security and environ-mental monitoring since the first visits of nuclear powered and nuclear capable vessels (NPV/NCVs) toCanadian harbours in the late 1960s. The outcomes of baseline monitoring and vessel visit sampling forthe period 2003e2012 are described for vessel visits to Halifax (NS), Esquimalt (BC) and Nanoose (BC).Data were obtained by gamma-ray spectroscopy using high purity germanium detectors. No evidencewas found for the release of radioactive fission or activation products by NCV/NPVs during the studyperiod, although anthropogenically produced radionuclides were observed as part of the study's baselinemonitoring. Background activities of Cs-137 can be observed in sediments from all three locations whichare derived from well-documented radioactivity releases. The detection of I-131 in aquatic plants isconsistently observed in Halifax at activities as high as 15,000 Bq kg�1 dry weight. These data aretentatively assigned to the release of medical I-131, followed by bioaccumulation from seawater. I-131was also observed in aquatic plants samples from Esquimalt (33 Bq kg�1) and Nanoose (20 Bq kg�1) for asingle sampling following the Fukushima Daiichi accident.

Crown Copyright © 2014 Published by Elsevier Ltd. All rights reserved.

1. Introduction

Following a process of safety evaluation and review, the firstnuclear powered/nuclear capable vessels (NCV/NPV), from theUnited States and Britain, entered Canadian ports in 1967. In sub-sequent years, several further environmental evaluations andtechnical safety assessments have been conducted. Initial andsubsequent assessments have concluded that the environmentalrisk associated with NCV/NPV visits is low. A comprehensivebaseline study of environmental matrices and foodstuffs was per-formed in 1996 (Waller and Cole, 1999). The Royal Canadian Navy(RCN) continues to develop and refine a Nuclear Vessel Visit SafetyProgramme (NVVSP). The latter document, which is updatedannually, is based on unclassified information and open discussion,although authorisation for external distribution resides with theRCN Nuclear Safety Officer. Central to the NVVSP are two NuclearEmergency Response (NER) teams based in Halifax, Nova Scotia andin Esquimalt, British Columbia; the latter covering both CFB

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Esquimalt and Canadian Forces Maritime Experimental and TestRange (CFMETR) in Nanoose, British Columbia. NER teams aretrained to respond to emergencies, but also conduct routine radi-ation monitoring during NCV/NPV visits. These teams take envi-ronmental samples during NCV/NPV vessel visits and obtainbaseline environmental samples according to a schedule defined inthe NVVSP. Seawater samples are taken during NPV/NCV visits aspart of a Visit Specific Strategy (VSS). Baseline sampling consists ofseawater, sediment, aquatic plants and sea-life to form a Contin-uous Sampling Strategy (CSS) programme. The collection, analysisand reporting of these samples form the RCN EnvironmentalRadionuclide Monitoring Programme (ERMP). All ERMP samplesare analysed by gamma-ray spectroscopy using high puritygermanium (HPGe) detectors at the Analytical Sciences Group(ASG) at the Royal Military College of Canada (RMCC) (Kingston,ON). To provide analytical resources on each coast, seawater sam-ples are also analysed using identical instrumentation at theDepartment of Occupational Health, Safety and Environment,University of Victoria (Victoria, BC) and the Dockyard Laboratoriesof Defense Research and Development Canada (Halifax, NS). Allthree laboratories are accredited to the ISO 17025 standard by theCanadian Association for Laboratory Accreditation (CALA) for ERMP

Table 1Radionuclides studied in the present work.

Element Isotopes

Barium Ba-140Cerium Ce-144Caesium Cs-134, Cs-136, Cs-137, Cs-138Cobalt Co-60Iodine I-131, I-132, I-133, I-134, I-135Lanthanum La-140Molybdenum Mo-99Niobium Nb-95Rubidium Rb-86, Rb-88Ruthenium Ru-103, Ru-106Strontium Sr-91Tellurium Te-129m, Te131m, Te-132Yttrium Y-90m, Y-91mZirconium Zr-95

D.G. Kelly et al. / Journal of Environmental Radioactivity 138 (2014) 303e307304

analyses. The purpose, structure and operation of the ERMP, as wellas the results of samples obtained during 2002 and 2003, have beenpreviously reported (Nielsen et al., 2007). The present work willbriefly describe and update ERMP structure and operation, whilstfocussing primarily on VSS and CSS data obtained during the period2003e2012.

The safety record of NPV/NCVs is extremely high. Releases ofradioactivity from NATO vessels are almost unknown. Evenfollowing the sinking of the Russian nuclear-powered submarine,Kursk, in 2000, radioactivity measurements of the submergedvessel in 2002 and during recovery in 2003 showed no significantrelease of radioactivity (Amundsen et al., 2002; Baranova et al.,2003). However, public concern is demonstrated by the mediaattention given to a leak from the nuclear powered submarine, USSHouston, in 2006e2008. The total loss of radioactive material fromthis vessel over a two year period was described as being compa-rable with the activity of a domestic smoke alarm. However, thevessel had visited a number of ports in both the US and Japan, andthe disclosure stimulated public concern (CNN, 2008). In contrast,medical radioisotopes do not seem to be of equivalent concern tothe general public. A number of studies have identified medicalradionuclides in sewage sludge, wastewater and surface water.Recent studies in the US (Hay et al., 2011; Rose et al., 2012, 2013),Europe (Fischer et al., 2009; Krawczyk et al., 2013) andAustralia (Veliscek Carolan et al. 2011), all quantify medical I-131 inthe environment, whilst some of these studies also identify thepresence of other medical isotopes, such as Ga-67, Tc-99m, In-111or impurities such as Mo-99, Ru-103 and Te-123m. The activitiesof I-131 measured in effluent routinely exceed 1 Bq dm�3. Theshort-half-lives and low environmental activities of these radio-isotopes present little risk and cause no public concern. However, itis essential that appropriate baseline and monitoring studies aremade to distinguish such medical radioisotopes from potential re-leases associated with NPV/NPV visits, since the misinterpretationof such data could stimulate unfounded public concern. The ERMPrepresents such a Canadian activity.

2. Experimental

Sampling has previously been described in detail (Nielsen et al.,2007). The CSS sampling strategy comprises the analysis ofseawater, sediment, plant and sea-life samples from NPV/NCV visitlocations in Halifax, Esquimalt and Nanoose (Table S1 andFigures S1eS3). The numbers of samples per annum are;seawater (12), sediment (4), plant (4) and sea-life (2) with thespecific sampling frequencies per location being described(Table S2). Sampling locations are defined by the size and tidalcharacteristics of the harbours and vary in number between threeand eight. The sampling programme cycles through these locations.All samples are grab samples with sediment, plants and sea-lifebeing obtained by RCN divers. Plant and sea-life samples arerepresentative of local flora and fauna, but not restricted to specificspecies. Typical inter-tidal seaweeds, such as Ascophyllum nodosum,Saccharina latissima and Fucus garneri are obtained. The majority ofsea-life samples consist of readily obtained crab and starfish spe-cies. VSS seawater samples are obtained immediately prior to NPV/NCV visits, then daily at high tide, and finally on departure. Samplesare collected in 1 dm3 polyethylene bottles and are transferred toASG, RMCC for analysis under chain of custody. Duplicate VSS andCSS seawater samples are also transferred to their respectivecoastal laboratories for analysis. Quality control procedures requirethat at least 10% of samples are obtained in duplicate for eachlaboratory. Samples are stored at 4 �C during shipping and prior toanalysis. Analytical procedures conform to ISO 17025. Seawater isanalysed as received using a 0.45 dm3 sample. Other matrices are

homogenised before the analysis of a 0.20 dm3 sample. A separatesub-sample is prepared to provide maximum surface area andanalysed for moisture content by drying to constant mass in astream of dry air at ambient temperature (sea-life and plants) or at110 �C (sediment). All data are reported in Bq kg�1 as time ofsampling activity. All data, with the exception of seawater, arepresented as dry weight values.

Analyses were conducted until 2009 using HPGe detectors of20% efficiency (Ortec GMX, Ortec, Oakridge, TN) with in-houseconstructed lead shielding (15.3 cm thickness) lined with 0.64 cmthickness oxygen-free high conductivity copper and 0.32 cmthickness plexiglass. Distances from the centre of the germaniumcrystal to shield were 17.8e19.1 cm. These systems were super-seded in 2009 by 40% efficiency GMX40P4-70-S systems from thesame vendor using commercial lead shielding with a tin/copperliner (Ortec, HPLBS1). Species-specific analyses of I-131 in plantswere conducted using a 60% efficiency detector (GEM60P4, Ortec).Calibration standards were obtained from AEA (Nielsen et al.,2007), and subsequently from 2006 onwards from Eckert andZiegler (Atlanta, GA). Control standards were obtained from IsotopeProducts (Valencia, CA) and latterly from the same laboratory aspart of Eckert and Ziegler. Until 2006 nine radionuclides (Co-57, Co-60, Sr-85, Y-88, Cd-109, Sn-113, Cs-137, Ce-139, Hg-203) were usedfor calibration and control, after which Pb-210 and Am-241 wereadded to improved efficiency calibration for low energy gamma-rays. Quality control procedures require the analysis of laboratoryblanks, typically tap water, and at least 10% of field samples areanalyses in duplicate by the laboratories. Analyses are accredited tothe ISO 17025 standard for 26 activation and fission products,although data are examined using extensive libraries of fission,activation and medical radionuclides. Typically, data for Co-60, Cs-137 and I-131 are reported, but all data above detection limit wouldbe reported to the RCN. Such data form part of annual reports whichare available to the public.

3. Results and discussion

The combination of CSS and VSS sampling protocols results inthe analysis of more than one hundred samples per annum, alongwith associated blank, control and duplicate data. For the 26accredited radionuclides considered (Table 1) over the ten-yearreporting period, the data matrix becomes excessively large.Moreover, given the due diligence nature of the programme, thereporting of such data are not useful. Thus, it can be stated thatduring the period of interest (2003e2012) no radionuclides havebeen observed above detection limits for any seawater samplesanalysed as part of the CSS programme. Detection limits are subject

Table 3NPV/NCV vessels to Canadian ports 2003e2012.

Year Location

Halifax Esquimalt Nanoose

Visits per annum

2003 0 4 32004 1 6 12005 5 3 12006 1 2 12007 2 4 02008 1 4 02009 0 1 02010 1 1 02011 2 0 02012 1 3 0

D.G. Kelly et al. / Journal of Environmental Radioactivity 138 (2014) 303e307 305

to sample background and ‘collection to counting’ delays. Typicaldetection limits derived from multiple analyses (n ¼ 8) are repre-sented by the mean and relative standard deviations (Table 2).These data represent detection limits obtained using upgradedhardware and shielding used from 2009. Detection limits usingolder systems were typically greater by a factor of two tofive (Nielsen et al., 2007). Thus, a baseline for the absence of fissionand activation products has been established at the detection limitsof the instruments used. It is not surprising that this baseline isestablished as non-detect data. Cs-137 represents a significantlong-term marker for fission product release based on its fissionproduct yield, volatility and half-life. However, studies of dispersedCs-137 in the North Atlantic almost a decade after Chernobylshowed activities in the mBq L�1 range (Dahlgaard et al., 1995),whilst modelling studies of Pacific seawater suggest that dispersionin the Pacific Ocean post-Fukushima will fall to similar levels(Nakano and Povinec, 2012). Since the objective of the presentstudy is to detect and quantify a local release of radioactivity, thefailure to detect such background activities does not detract fromthe purpose of the study. During the study period 48 visits of NPV/NCV have occurred to the three authorised locations, with 14, 28,and 6 visits occurring in Halifax, Esquimalt and Nanoose, respec-tively. It is evident that such visits occur as a function of operationalrequirements and occur at markedly different frequencies fromyear to year (Table 3). Once again, no data above detection limitshave been recorded for the seawater samples obtained during thesevisits.

A single radionuclide, Cs-137, has been identified from theanalysis of ocean sediments. Cs-137 has been observed at all threesampling locations throughout the period of study, with dry weightactivities never exceeding 10 Bq kg�1 and on numerous occasionsbeing below the ca. 1 Bq kg�1 detection limits of the gamma-rayspectrometers used for analysis. The Cs-137 observed is assumedto be derived from atmospheric weapons tests dating to the 1950sand 1960s (Olsen et al., 1981; Ravichandran et al., 1995) and morerecently from the Fukushima Daiichi disaster in 2011. Given thehalf-life of caesium-137 (30.07 a), it is reasonable to suggest that adecline in measured activities should have occurred during thestudy period, with an increase of undefined magnitude followingthe environmental transport of fission products from the last ofthese events. In practice, it has not been possible to distinguishdecay or the contribution from the Fukushima Daiichi disaster fromnormal variations in sampling uncertainties. Detailed core studiesin other locations suggest that sedimentation rates and mixing inupper sediment layers greatly affect observed activities (Fulleret al., 1999). Such complexities are illustrated in the present workby data obtained from Halifax Eastern Passage, Fig. 1. Six of the tensamplings afforded data above detection limit. Regression analysesof these data, or all data assuming activities at the detection limitfor non-detect data, produced regression analyses of activity versustime for which the slope obtained could not be distinguished fromunity at 95% confidence. Since fission represents the source of Cs-137, it should be accompanied by Cs-134, although their different

Table 2Typical sample-to-sample detection limits obtained for ERMP samples matricespost-2009 (n ¼ 8).

Radionuclide Matrix

Seawater Sediment Aquatic plants Sea-life

Detection limit/[Bq kg�1]

I-131 0.29 ± 0.06 0.53 ± 0.16 5.3 ± 2.3 3.7 ± 2.8Cs-137 0.18 ± 0.05 0.54 ± 0.17 3.7 ± 1.7 4.0 ± 5.1Co-60 0.14 ± 0.04 0.32 ± 0.10 4.2 ± 2.6 2.6 ± 1.8

mechanisms of formation result in a burn-up dependent ratio.Initial Cs-134/Cs-137 ratios after Chernobyl were 0.5e0.6 (De Cortet al., 1998). In the present work Cs-134 could not be observedabove instrument detection limits (0.34 ± 0.06 Bq kg�1, n ¼ 8) atany period during the study. Such observations are reasonablyconsistent with initial caesium ratios following Chernobyl, the half-life of Cs-134 (2.06 a) and the 17 year elapse to the commencementof analyses. The global transport of Cs-134 and Cs-137 post-Fukushima Daiichi must contribute to recent caesium measure-ments to some degree. However, given that the Cs-134/Cs-137 ratiofrom this event has been established as 0.98 ± 0.01 (Merz et al.2013), the absence of detectable Cs-134 suggests that theincreased radio-caesium burden from this event did not greatlycontribute to the existing radionuclide activity.

In a similar manner to sediment, the analysis of aquatic plantsamples results in the detection of a single radionuclide, in this caseI-131. Detection limits are higher than those of other matrices,although this largely reflects the dry weight reporting basis andhigh moisture content of aquatic plant material (Table 2). Incontrast to Cs-137 in sediment, I-131 detection in aquatic plantsvaries greatly as a function of location. Historically, I-131 has notbeen detected in aquatic plants obtained from Esquimalt andNanoose. However, aquatic plant samplings occurred on 23 March2011 in Esquimalt (Jetty A) and the following day in Nanoose (FleetPoint Marina) which yielded 33 and 20 Bq kg�1 dry weight I-131,respectively. These samplings are 11 and 12 days after the first re-leases of radioactivity at the Fukushima Daiichi reactor facility(Thakur et al., 2013). Sampling dates are close to peak I-131

Fig. 1. Cs-137 activities observed in sediment at Halifax eastern passage for the period2003e2012. Data below (◊) and above (A) detection limit shown. Error bars representone sigma uncertainty.

Table 4Species specific I-131 analysis conducted following sampling in December 2006 inShearwater, NS.

Plant species Dry weight fraction Activity

/% /[Bq kg�1]

Ascophyllum nodosum 33 28 ± 1Ascophyllum nodosum 33 26 ± 1Ascophyllum nodosum 26 44 ± 2Ascophyllum nodosum 32 9 ± 2Ascophyllum nodosum 25 43 ± 4Saccharina latissima 9 274 ± 8Saccharina latissima 12 45 ± 2Saccharina latissima 12 91 ± 5Saccharina latissima 9 203 ± 8a

Saccharina latissima 7 319 ± 6Saccharina latissima 12 92 ± 3

a Mean of duplicate data (214 ± 6) and (191 ± 6) Bq kg�1.

D.G. Kelly et al. / Journal of Environmental Radioactivity 138 (2014) 303e307306

activities observed in kelp at other Pacific coast locations (Manleyand Lowe, 2012) and are consistent with I-131 measurements inrainwater from the Pacific coast of the US during the same period(Norman et al., 2011), assuming both rainwater dilution in surfaceseawater and bioaccumulation by kelp and similar species (La Barreet al., 2010). Subsequent ERMP sampling of aquatic plants at thesame locations on 7 and 22 July could not detect residual I-131(<1.5 Bq kg�1 and <8.1 Bq kg�1, respectively). Although releases ofradioactivity at Fukushima Daiichi have continued to occur, theserepeat samplings correspond to >12 half-lives after the initial I-131peak.

In contrast to the data obtained from Canada's west coast, I-131has been routinely identified in aquatic plants sampled from Hal-ifax throughout the ERMP. Given the short half-life of I-131 (8.07 d),detection limits are susceptible to transportation times, as well asdry weight mass. However, measured activities are greater thandetection limits for almost all data gathered during the 10-yearstudy period, Fig. 2. Typical detected activities have been in therange (10e100) Bq kg�1 at all three Halifax sampling points. Asignificant spike occurred in December 2005 providing peaks ac-tivities of 15,000 Bq kg�1 at the Shearwater Jetty A location. Sub-sequent sampling at this location and at NCP/NCV berths displayeddeclining activities of <1000 Bq kg�1, although such data stillexceeded historical norms. In the absence of other fission products,and given the observation of I-131 in plants throughout the studyperiod, such data cannot be related to NCV/NPV visits. Moreover,there is evidence of medical I-131 use in Halifax. Hyperthyroidtherapy and thyroid ablations are performed routinely at HalifaxVictoria Hospital. Information provided by the area RadiationSafety Officer, indicates that in 2005, 50 patients were treated witha total of 231 GBq of I-131 of which 77 GBq was estimated to bedischarged to the sewer system.Whilst this activity is not dissimilarto other years, I-131 is primarily excreted in urine and localiseddischarge is feasible. In support of this mechanism, the relationshipbetween medical I-131 and environmental detection has beenestablished at a number of locations globally (Veliscek Carolan et al.2011; Rose et al., 2013). In Halifax, attempts to determine trends inI-131 activity have proved unsuccessful. Statistically valid trends

Fig. 2. I-131 activities observed in aquatic plants at Halifax for the period 2003e2012. SamplOpen symbols denote less than detection limit data. Error bars represent one sigma uncert

expressed chronologically, or as a function of season or locationhave not been observed. Whilst parameters must exist whichgovern the release, uptake and decay of this short-live isotope, theycan not be elucidated from the present data.

The absence of detectable I-131 from seawater in the vicinity ofaquatic plants containing measurable levels of the same radionu-clide clearly suggests the bioaccumulation of iodine. Such behav-iour is common in intertidal plants (Ar Gall et al., 2004). To facilitatefurther investigation, controlled samplings of specific aquatic spe-cies were made in December 2006. Samples were obtained by navydivers adjacent to the Shearwater Yacht Club and Shearwater Jettylocations that had been associated with previous high levels of I-131 in aquatic plants. Sampling was observed by one of the authorsto confirm the validity of sampling, storage and transport. Plantspecies were identified and analyses were performed on a species-specific basis. Two significant aquatic plant species were obtainedand analysed, A. nodosum and S. latissima, (Table 4). Mean dryweight activities of (30 ± 14) and (170 ± 110) Bq kg�1 wereobserved (n¼ 5 and n¼ 6) respectively. The data obtained for thesetwo plants species were determined to be significantly different (t-

ing locations; Shearwater Jetty A (:), Shearwater Yacht Club (-), NCV/NPV Berths (A).ainty.

D.G. Kelly et al. / Journal of Environmental Radioactivity 138 (2014) 303e307 307

test, a ¼ 0.05, t ¼ 3.06, p ¼ 0.028). Such data are consistent withliterature data for the relative dry weight concentrations of stableiodine in A. nodosum and S. latissima of 275 mg g�1 and 574 mg g�1,respectively (Martinelango et al. 2006). Thus, differences in I-131may be attributed to the higher surface area to weight ratio of S.latissima, as at least in L. digitata, it has been demonstrated that(50e80) % of iodine occurs in peripheral tissue (Amat, 1985). SinceI-131 is not observed in seawater, but appears to bioaccumulate inaquatic plants, it is useful to consider published datawith respect tototal iodine in A. nodosum and S. latissima, and in seawater, to es-timate iodine bioaccumulation in these species. The data presentedfor stable iodine in these plants may be combined with for iodine inNorth Atlantic waters, ca. 0.055 mg g�1, (Elderfield andTruesdale1980), to give bioaccumulation factors of 5000 and10,400, respectively. Application of these factors to the mean I-131activities reported in aquatic plants in the present work suggests I-131 concentrations in the same locations between 0.002 and0.006 Bq kg�1. Such activities lie significantly below the detectionlimit activities in seawater obtained in the present work (Table 1),and thus support the absence of data above detection limits in VSSand CSS seawater analyses. Such estimates must however be madewith caveats; the chemical speciation of iodine in seawater andaquatic plants is complex and the establishment of equilibria havenot been demonstrated.

Despite the presence of Cs-137 in sediment and I-131 in aquaticplants, at least in the Halifax location, none of the radionuclideslisted (Table 1) has been detected in sea-life analyses. These sam-ples are collected by navy divers and represent a broad spectrum ofanimal species present in the sampling locations. Whilst not rep-resenting a comprehensive delineation of radionuclide distribution,they do demonstrate the absence of fission and activation productsin animal species and thus provide baseline data at the detectionlimits identified (Table 2).

4. Conclusions

The study is consistent with the safety record of NCV/NPV visitsto Canadian harbours. Data provide no evidence of the release offission and activation products from such visits. Baseline moni-toring does detect anthropogenic radionuclides from other sources,specifically Cs-137 and I-131. The former is globally distributed insoil and sediment as a result of well documented fission productreleases. I-131 is routinely observed in aquatic plants in Halifax, andfrom Esquimalt and Nanoose following the Fukushima Daiichi ac-cident. The detection of these radionuclides demonstrates theimportance of baseline studies in support of NCV/NPV radionuclidemonitoring.

Acknowledgements

Financial support with respect to the operation of the ERMP andthe provision of analytical instrumentation was provided by theRoyal Canadian Navy. Three institutions have participated in theanalysis of samples at coastal laboratories during the period dis-cussed; the Dockyard Laboratory of Defence Research and Devel-opment Canada Atlantic, the British Columbia Centre for DiseaseControl and the Department of Occupational Health, Safety andEnvironment of the University of Victoria. The contributions ofthese institutions and their staff are gratefully acknowledged. Dr. C.Lane, Dalhousie University, is thanked for his help in the identifi-cation of aquatic plant species.

Appendix A. Supplementary material

Supplementary material related to this article can be foundonline at http://dx.doi.org/10.1016/j.jenvrad.2014.05.023.

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