MERCURY, METHYLMERCURY, AND OTHER HEAVY METALS IN MUKTUK, MUSCLE, AND SOME ORGANS OF BELUGAS (Delphinapterus leucas) FROM THE WESTERN CANADIAN ARCTIC.
Final Summary Report to the Fisheries Joint Management Committee of the Inuvialuit Settlement Region
R. Wagemann
Department of Fisheries and Oceans Central and Arctic Region 501 University Crescent, Winnipeg, R3T 2N6
December 19, 1994 ,...')
MERCURY, METHYLMERCURY, AND OTHER HEAVY METALS IN MUKTUK, MUSCLE, AND SOME ORGANS OF BELUGAS (Delphinapterus leucas) FROM THE WESTERN CANADIAN ARCTIC.
Final Summary Report to the Fisheries Joint Management Committee of the Inuvialuit Settlement Region
R. Wagemann
Department of Fisheries and Oceans Central and Arctic Region 501 University Crescent, Winnipeg, R3T 2N6
December 19, 1994 i
Table of Contents
From the Author: ...... 1
Acknowledgments ...... 1
Summary ...... 2
Recommendations ...... 5
Introduction ...... 7
Materials and Methods ...... 9
Results and Discussion ...... 11
Group Differences ...... 11
Methylmercury ...... ·...... 13
Muktuk...... 13
Muscle ...... 14
Liver 15
continued on next page ii
Table of Contents (cont'd)
Total Mercury ...... 16
Muktuk...... 16
Muscle ...... 22
Liver ...... 24
Kidney ...... 26
Total Metals (Pb, Cd, Cu, Zn, Se) ...... 27
References ...... 30
Appendix I. Means - 1993: ...... 33
Appendix II. Means - 1994: ...... 37 1
From the Author: This is the final summary report encompassing all the metal contaminants work done to date on belugas of the western Arctic. The work was funded by FJMC and DIAND, and I dare say, that it would not have been possible without this funding and the cooperation of the · HTC's and the Native hunters of the various regions. I consider this report to be the culmination of a successful joint effort between the Native people, their representatives, the funding agencies, and a scientist and his coworkers. I wish to extend my sincerest thanks to all the parties involved for their help and cooperation.
Wishing you a happy and joyous Holiday,
R. Wagemann Research Scientist
Acknowledgments
We thank G. Boila, DFO, (metals in organs and muscle) the following contractors E. Trebacz and B. Kempin (methylmercury), H. Kozlowska (metals and methylmercury in muktuk) and D. Savoie (metals in organs and muscle) for analytical work during various times of the project. We also thank the Native Elders and hunters of the western Arctic region for supporting the project and providing the tissue samples, and the Hunting and Trapping Association for facilitating the procurement of the samples. This project was financially supported by the Fisheries Joint Management Committee and the Department of Indian and Northern Development of Canada through the Northern Contaminants Program. The planning discussions with R. Bell, and the logistical support rendered by B. Ferguson and M. Stabler were greatly appreciated. 2 Summary
Total mercury concentrations in liver, kidney, muscle, and muktuk largely exceeded the Canadian Government Guideline (0.5 µgig wet wt) for fish export and consumption. The overall mean concentrations, ± Sd, (n) and concentration range (µgig wet wt) of total mercury and methylmercury in tissues of all western Arctic belugas collected between 1981 and 1994 were as follows:
Muktuk Muscle Liver Kidney Total 0.77±0.41 1.17+0.62 20.5±20.3 4.17+2.77 Hg 67 111 120 116 0.19-1.93 0.41-3.44 0.13-99.5 0.21-13.6 Methyl 0.68±0.37 1.31 ±0.65 1.85±1.20 t Hg 66 77 75 0.14-1.71 0.35-3.16 0.11-6.13 t---- kidney tissue was not analyzed for methylmercury
The average mercury concentration (1.17 µgig wet wt) in muscle of belugas (all years combined) from the western Arctic was more than twice the recommended concentration guideline for fish muscle (0.5 µgig wet wt). In 93 % of the belugas sampled between 1981 and 1994 (103 out of 111 animals) this guideline was exceeded. The average mercury concentration in muscle of animals with Hg >0.5, was 1.23 µgig wet wt. Total mercury in muscle was significantly, positively correlated with the age of animals. In general, animals that were approximately four years and older had mercury concentrations in muscle > 0.5
µgig wet wt.
There were significant differences between the annual means of mercury in liver and 3 kidney, nevertheless, a temporal trend was not indicated when age differences between the groups were taken into account.
Methylmercury in muscle was approximately 100 % of the total mercury and as such, most animals had also significantly higher concentrations of methylmercury than 0.5 µgig wet wt, in muscle. As for total mercury, 92 % of the animals sampled had concentrations of methylmercury >0.5 µgig wet wt.
The total mercury concentration in muktuk (the skin as a whole) was on average 0.81 and 0.73 µgig wet wt in beluga collected in 1993 and 1994, respectively. In the combined sample (1993 and 1994) it was 0.77 µgig wet wt. The total mercury concentration in muktuk of belugas, while lower than in muscle, exceeded the 0.5 µgig wet wt concentration level in
61 % of the animals (41 out of 67). Only animals 16 years and older appeared to have mercury concentrations in muktuk >0.5 µgig wet wt. Muktuk samples were not collected prior to 1993.
The average methylmercury concentration in muktuk was lower than in muscle, and fewer animals had methylmercury concentrations in muktuk >0.5 µgig wet wt, compared to the number of animals which exceeded this level in muscle.
As is normally the case, the total mercury concentration was highest in the liver of belugas ; approximately 18 times higher than in muscle. The total mercury concentrations, in muscle, liver and kidney, were strongly, positively correlated with the age of the animals.
Only approximately 9 % of the total mercury in the liver was methylmercury, 1.9
µgig wet wt on average. This was approximately, only 1.4 times higher than in muscle.
The zinc concentration was approximately three times higher and the selenium 4 concentration nine times higher in muktuk (66 and 3.6 µgig wet wt, respectively) than in muscle, making muktuk a good source for consumers of these two essential elements.
In addition to muktuk (i.e. the skin as a whole), individual strata of the skin, from 27 belugas, were analyzed for mercury. Total mercury was not uniformly distributed throughout the skin of belugas, but increased progressively outward with each stratum. The concentration was on average only 0.29 µgig wet wt, in the innermost layer (dermis) and
1.5 µgig wet wt, in the outermost layer (degenerative epidermis). The thickness and density of each skin stratum were also measured and the surface area of an average-size beluga was estimated. From these measurements the excretion rate of mercury through molting, for an
1 average-size beluga, was calculated to be 14129 µg·year- , which constituted 20 % of the total mercury in the skin as a whole. The rate of loss was a function of the size and age of an animal. 5 Recommendations
1. In view of the relatively high concentration of total mercury in belugas from the
western Arctic, notably in muktuk, muscle and liver, tissues from a sufficiently large
sample of belugas (40 -50 animals) from the eastern Arctic should be similarly
analyzed for total and methylmercury (as for the western Arctic). This should be done
to provide a basis for spatial comparison between the two regions, and to provide a
contaminants information data base on belugas from the eastern Arctic to the Native
people similar to that now available to the western Arctic Native people.
2. Methylmercury in tissues of belugas from the eastern Arctic, notably in muktuk and
muscle, should be determined for a sufficiently large sample of animals based on the
same rationale as stated under point 1.
3. The individual layers of skin of beluga from the eastern Arctic (degenerative
epidermis, stratum externum, stratum intermedium, dermis) should be analyzed for
total mercury and methylmercury, as a follow-up to the work on western Arctic
beluga, in order to be symmetrical in the provision of consumer-related contaminants
knowledge to eastern and western Arctic Indigenous people. 6
Recommendations (cont'd)
4. In view of the relatively high concentration of total mercury in narwhal muscle (as
determined 15 years ago) and possibly in muktuk, a sufficiently large sample of
narwhal (40-50) should be analyzed for mercury and methylmercury, based on the
) ) rationale stated under point 1., and in order to gain a wider perspective on ) contaminants in these Arctic whales. No systematic metals data for muktuk of
narwhal from the eastern Canadian Arctic can be presently found in the literature.
5. a.) In view of the high concentration of cadmium in organs of narwhal from Pond
Inlet, as determined 15 years ago, this location should be revisited and a sufficiently
) large number of narwhal sampled (40-50 animals) and the tissues analyzed for
) cadmium and other metals (Se, Cu, Zn, etc.) in order to confirm or refute the earlier, ) ) extraordinarily high cadmium levels. ) ) b.) Tissues of narwhal should be collected at a second location in the eastern Arctic
) and analyzed for cadmium and other metals. This would establish whether or not the J ,) narwhal from Pond Inlet are unique in their high cadmium levels. ) c.) If cadmium levels in narwhal are confirmed to be high, the toxicity of cadmium ) ) should be assessed through analysis of metallothionein and the cadmium associated ) ) with this protein, in order to put in perspective potential effects from cadmium on ) j animals, and to convey factual information to Indigenous people in this regard. ) j
) ) 7 Introduction
This report deals with metals and methylmercury in beluga tissues (liver, kidney, muscle, skin, i.e. muktuk) from the western Arctic, and represents the completion of the survey work on metal contaminants and methylmercury in belugas from the western
Canadian Arctic. The metals analyzed for in tissues of belugas were, Hg, Cd, Pb, Se, Cu,
Zn, and methyl.mercury. The report encompasses the most recent, previously unpublished data on belugas collected in 1994, some data previously not reported on belugas collected in
1993, and also data from the literature on metals in belugas from this area, thereby providing an overview of the available data on belugas from the western Canadian Arctic and a basis for temporal and spatial comparisons of contaminants in belugas with other regions.
Although four different tissue types were analyzed (muktuk, muscle, liver, kidney), greater emphasis was placed in this report on muktuk than on other tissues because muktuk has been analyzed for metal contaminants only recently, and mercury was found not to be uniformly distributed in this tissue.
A number of investigators have described the structure of the skin of some cetaceans, most recently, Jones and Pfeiffer (1994), and St. Aubin et al. (1990). Their work provided the basis for identification and naming of skin strata. The skin consists basically of four strata, the outermost layer (degenerative epidermis), underlain by the stratum extemum, which in tum is underlain by the stratum intermedium and finally the innermost layer, the dermis, which is underlain by blubber. The seasonal epidermal molting of belugas has been described by Smith et al. (1992). Belugas molt in the summer in near-shore shallow water 8 and estuaries by rubbing their bodies against bottom sediments, sandbars, pebbles and stones.
During molting the degenerative epidermis and stratum externum are shed, and parts of the next, thicker layer, the stratum intermedium, can apparently, also be shed at times (Smith et
al. 1992).
Although mercury concentrations in tissues other than skin of Arctic cetaceans have
been reported (Hansen et al. 1990; Wagemann et al. 1990; Wagemann et al. 1983),
information on mercury in the skin was lacking. The purpose of this investigation was
primarily to measure mercury and methylmercury concentrations in muscle and muktuk (the
skin as a whole), and in individual layers (strata) of the skin to see how it was distributed
within the skin and how much mercury the animals might loose through molting. However,
other tissues were also analyzed for mercury and other metals. It was felt to be important,
also to monitor for contaminants in other tissues, such as liver and kidney as we have done,
since these tissues can reveal contaminant effects, trends, and correlations more readily than
can contaminants in muscle or skin.
The Inuit in the coastal communities of the Canadian Arctic and Greenland continue
to hunt beluga and narwhal for food. The meat and skin are eaten raw or cooked and the
skin, called "muktuk", is sometimes also eaten after ageing (fermenting). Muktuk remains to
this day one of most sought-after foods and is considered to be a delicacy by the Inuit.
Muscle (flesh) and muktuk of beluga constitute a dietary supplement and substances such as
methylmercury, total mercury, and other contaminants in these tissues are therefore of prime
concern to consumers. 9 Materials and Methods
Most recently, July, 1993 and 1994, belugas were sampled during Native hunts at four different locations ( 27 animals), and two different locations (46 animals) in the western
Arctic, in the respective years. Two belugas from the eastern Arctic (Repulse Bay on the
Melville Peninsula) were sampled in October 1993 .
Table 1. The total number of belugas collected at different locations in the western
Arctic and Repulse Bay in 1993 and 1994, mean age±standard deviation
(years) and the number of females and males per group (F/M).
Location 1993 Age F/M 1994 Aget F/M East Whitefish 13 29±10 1112 13 0/13 Shingle Point 2 17±3 3/2 Paulatuk 3 15±8 1/2 Hendrickson Isl. 9 22±8 3/2 33 7/26 Repulse Bay 2 5/7
----t not available at the time of writing of this report
The sampling protocol has been described previously (Wagemann et al. 1990, 1983).
Muktuk samples were taken laterally on the axillary girth, and flesh (muscle) samples were
taken from the longissimus dorsi muscle. The tissue samples were stored in a freezer (- 10
40°C), and prior to analysis were thawed just sufficiently to be cut. Analyses for metals were performed on wet (or dried, 1993) tissues. The tissues were digested and analyzed for total mercury by cold-vapor atomic absorption (Wagemann et al. 1990). Other metals were analyzed by Zeeman flameless or flame atomic absorption depending on the concentration of a metal in a tissue. At low metal concentrations pre-concentration by complexing and extraction into an organic solvent preceded analysis as described in detail elsewhere
(Wagemann et al. 1990). Working standards were made from certified, aqueous concentrates.
The accuracy of results was periodically checked with various (depending on the concentration of the metal in the tissue) standard reference materials, (U.S. NBS Bovine
Liver, Dolt-1, NRC; Dorm-1, NRC). Results were not accepted unless the calibration value fell within the error limits of the certified value. Methylmercury in muscle was determined by homogenizing the tissue with an acidic, aqueous medium, extracting methylmercury with an organic solvent, mineralizing the organic solvent and analyzing for mercury by cold-vapor atomic absorption. Methylmercury analyses by this method were checked for correspondence by capillary column GC with electron-capture detector(ECD). For muscle the two methods agreed. Methylmercury concentrations in liver reported here, were obtained entirely by capillary column gas-chromatographic analysis with (ECD). The procedure of Uthe et al.
(1972), was used for extracting methylmercury from tissues and pre-analysis treatment of
samples. Working standards (5-100 ng/ml) were made up with methylmercuric iodide (K &
K Laboratories, Cleveland, Ohio, USA) in toluene. The injection volume was 1 µL. The
accuracy of results was periodically checked with a certified reference material (Dorm-1,
· NRC) which was processed in the same way as a sample. Some values fell within the error 11 range of the certified value, but most were somewhat (15 %) ouside the lower limit. All methylmercury concentrations are expressed in terms of Hg, i.e. µg Hglg of tissue.
The determination of previously reported ages of belugas has been described (Sheffer and Myrick, 1980; Wagemann et al. 1990, Wagemann, 1993).
The different layers of the skin were identified visually by their natural coloration and were carefully dissected. The morphological description of the skin of belugas by St. Aubin et al. (1990), was used as a guide, and their designation of the four strata was adopted. To estimate the quantity of mercury in the individual layers of the skin, the thickness of each stratum, the weight of a unit area, the density of each stratum, and the concentration of mercury in each stratum were measured for a number of animals. The surface area for an average-size beluga (from a group of 27) was estimated from a calibration of length vs surface area using data for belugas given by Doige (1990).
Results and Discussion
Group Differences
The number of belugas sampled in 1993 and 1994 in the western Arctic, the sampling sites, and the ages and number of males and females sampled are shown in (Table 1). Some of the 1993 data have been reported before (Wagemann, 1993), but are included here for comparison and the sake of completeness. The mean concentrations of the five groups (5 locations) collected in 1993 (Appendix 1), did not differ significantly from each other
(a=0.05) for any of the metals and methylmercury in any of the tissues (muktuk, muscle, liver, kidney), except cadmium and mercury in liver and kidney of the three animals from 12
Paulatuk and the two animals from Repulse Bay. Clearly, these numbers did not constitute sufficient sample sizes. Data from all five locations were therefore combined into an annual mean (1993).
Metal and methylmercury mean concentrations in the two groups (two sites) collected in 1994 (Appendix 2) did not differ significantly for any of the tissues and these two locations were combined into an annual mean (1994).
Mercury data for belugas collected in 1981 and 1984 from the Mackenzie Delta have been published (Wagemann et al. 1990) but are included here for comparison with subsequent collections and for the sake of completeness. Belugas were not sampled for muktuk prior to 1993. Annual means for total and methylmercury and other metals in muktuk were compared (a=0.05). Because no significant differences were found between the annual means, the overall mean for each metal and methylmercury (for all the years combined), was calculated for each tissue (Table 2).
Table 2. Overall mean±Sd, (n), and concentration range (µgig wet wt) of methyl and total mercury in tissues of all western Arctic belugas collected between 1981 and 1994.
Muktuk Muscle Liver Kidney Total 0.77±0.41 1.17±0.62 20.5±20.3 4.17±2.77 Hg 67 111 120 116 0.19-1.93 0.41-3.44 0.13-99.5 0.21-13.6 ____ t Methyl 0.68±0.37 1.31 ±0.65 1.85± 1.15 Hg 66 77 79 0.14-1.71 0.35-3.16 0.11-6.13
t---- kidney tissue was not analysed for methylmercury. 13
All tissue concentrations of metals and methylmercury are given in terms of fresh weight (i.e. wet wt) so as to be directly comparable with the mercury guideline for fish ( 0.5
µgig wet wt). Division of "wet wt" concentrations by 0.307 for muscle, by 0.322 for liver and by 0.241 for kidney converts these to a dry weight concentration basis.
All methylmercury concentrations are expressed in terms of Hg, i.e. µg Hglg of tissue.
Methyl.mercury
Muktuk
Beluga tissues sampled in 1981 and 1984 were not analyzed for methylmercury.
Muktuk collected in 1993 and 1994 was analyzed for methylmercury. The annual means for muktuk, 0.73 and 0.64 µgig wet wt, for 1993 and 1994, respectively (Table 3), were not significantly different from each other (a=0.05; Scheffe's multiple means comparison test;
Scheffe, 1959). The overall mean (1993 and 1994) was 0.68 µgig wet wt (Table 2).
Table 3. Mean±Sd, (n), and concentration range, µgig wet wt, of metals and methyl mercury in muktuk, of belugas from the western Arctic collected in 1993 and 1994.
Year Pb Cd Zn Cu Se Hg CH3Hgt
1993 :50.02 0.002±0.002 65.5±6.60 0.46±0.08 0.80±0.43 0.73±0.42 30 30 30 30 29 28 0.001-0.009 43.5-79.7 0.34-0.72 0.19-1.85 0.14-1.71
1994 3.60±0.86 0.73±0.40 0.64±0.32 38 38 38 1.03-5 .75 0.23-1.93 0.21-1.34
t Hg determination in organic solvent extract by AA analysis. 14
Table 4. Mean+standard deviation, (n), and concentration range, µgig wet wt, of metals and methylmercury in muscle of belugas from the western Arctic collected in 1981 to 1994.
Year age Pb Cd Zn Cu Se Hg CH3Hgt
1981§ 12.3 ±4.4-0 0 .03±0.11 0.12±0.25 22.4±5.23 3.76±14.6 0.60±1.34 1.04± 1.34 _i 26 28 34 34 34 34 33 2.00-21.5 0.002-0.58 0.008-1.34 12.9-33.0 0.68-86.0 0.30-8.20 0.41-8.35
1984§ 21.1±9.20 0.016 0.009 28.4 0.74 0.30 1.03 _; 8 1 1 12.5-42.0
1993 24.2±9.88 :50.02 0.03±0.02 26:7±9.8 0.70±0.16 0.40±0.07 1.38±0.69 1.41±0.72 27 31 31 31 31 31 31 31 9.83-41.2 <0-001-018 0.008-0.12 12.6-52.2 0.46-1.16 0.24-0.53 0.42-2.64 0.38-2.57
1994 _.. :50.006 0.015 ±0.01 25 .0±5.00 0.77±0.18 0.42±0.10 1.29±0.65 1.25±0.61 46 46 46 46 45 46 46 <0.001-0.006 0.005-0.053 15.0-40.4 0.47-1.34 0.24-0.66 0.41-3.44 0.35-3.16
§ 1981 & 1984 data are from: Wagemann et al. (1990). t ---- Hg determined in organic solvent extract by AA analysis. *----not analyzed for methylmercury *---- Age data were not available at the time of writing of report.
Preliminary indications are that methylmercury in muktuk may be less than 100 % of the total mercury, but this has to be further investigated.
Muscle
The annual means of methylmercury for muscle, 1.41 and 1.25 µgig wet wt, for 1993 and 1994, respectively (Table 4), were significantly higher than for muktuk, clearly exceeding the 0.5 µgig wet wt guideline for fish. There was no significant difference between the two annual methylmercury means for muscle. The overall mean for muscle 15
(1993 and 1994 combined) was 1.31 µgig wet wt (Table 2). The mean concentration of methylmercury for muscle of belugas was significantly higher than for muscle of ringed seals
(0.37 µg Hglg, wet wt) from approximately the same area in the western Arctic (Wagemann,
1993). In muscle of belugas, methylmercury comprised approximately 100 % of the total mercury. In 92 % of the animals (71 out of 77) the 0.5 µgig wet wt, guideline was exceeded, and these animals had a mean methylmercury concentration in muscle of 1.39
µgig wet wt. Methylmercury concentrations in muscle were largely a reflection of the total mercury concentration in this tissue.
Liver
The mean methylmercury concentration in the liver of belugas sampled in 1993 and
1994, as determined by capillary-Ge with ECD, was 1. 72 and 1.93 µg Hglg, wet wt, respectively (Table 5), and the overall mean was 1.85 µg Hglg, wet wt (1993 and 1994 combined) (Table 2). This was only a factor of 1.4 times higher than the methylmercury concentration in muscle. Methylmercury in the liver was approximately 9 % of the total mercury in this tissue. It must be emphasized that fairly large standard deviations were associated with the means and percentages, indicating wide variations in the methylmercury concentration and the fraction of methylmercury among individuals. Methylmercury was not determined in kidney. 16
Table 5. Mean±Sd, (n) and concentration range, µgig wet wt, of metals and methyl- mercury in liver of belugas from the western Arctic collected in 1981 to 1994.
Year Pb Cd Zn Cu Se Hg CH3Hg*
1981' 0.007±0.008 2.29±1.50 24.3±4.82 13.1±11.8 5.58±4.42 10.7±10.9 31 35 35 35 35 34 0.002-0.037 0.08-6.80 14.5-33.8 0.81-52.2 0.26-19.5 0.13-46.9
19841 0.021 ±0.009 2.50±1.61 27.9±3.55 15.3±18.3 9.79±8.21 17.8±16.5 8 8 8 8 8 8 0.008-0.037 1.33-5 .81 23.2-33.2 6.01-60.3 4.34-24.6 3.44-47.7
1993 0.02±0.01 2.82±2.47 27.2±5.82 11.5 ±8.85 19.8± 14.9 29.2±25.8 1.72±1.13 34 34 34 34 34 34 34 0.003-0.07 0.13-13.4 10.8-38.2 1.07-34.5 1.01-56.4 0.31-99.5 0.11-4.90
1994 0.012±0.013 2.19±0.91 28 .8±5.54 11.6±6.70 17.4± 13.7 24.4±23.8 1.93±1.17 43 45 45 45 45 45 45 <0.001-0.077 0.15-4.99 11.9-46.2 0.81-35.1 0.72-58.7 0.47-116.3 0.17-6.13
§ 1981 & 1984 data are from Wagemann et al. 1990. * methylmercury determined by capillary-Ge with ECD.
Total Mercury
Muktuk
The mean mercury concentration in muktuk (skin as a whole) was 0.80 and 0.73 µgig wet wt, in the 1993 (29 animals) and 1994 (38 animals) groups, respectively (Table 3). The difference between these means was not significant at a=0.05, by Scheffe's multiple means comparison test (Scheffe, 1959). The two means were combined, and the resultant overall mean was 0.77 µgig wet wt (Table 2). All means exceeded somewhat the Government of
Canada guideline (0.5 µgig, wet wt) for consumable and exportable fish. · 17
35
25
15
5
0.0 0.4 0 .8 1. 2 1.6 2.0 2.4 2.8 Hg µg / g
Figure 1. Frequency distribution of mercury concentration in muktuk of belugas (67 animals) from the western Arctic in the combined sample of 1993 and 1994.
Of the 67 animals in the combined sample (1993 and 1994), 61 % (41 out of 67 animals) had mercury concentrations in muktuk in excess of 0.5 µgig, and these animals had a mean concentration of 1.03 µgig (wet wt) as is evident from the frequency distribution graph for mercury in muktuk (Fig. 1) . In the 1993 sample, 69 % (20 out of 29 animals) had a mercury concentration greater than 0.5 µgig,, and this group had a mean concentration of
0.99 µgig (wet wt), (Wagemann et al., 1993). Beluga muktuk (also narwhal muktuk) is considered to be a delicacy by native Canadians and Greenlanders. The combined, larger sample, essentially confirmed the previously reported results (Wagemann, 1993). 18 The correlation between age and total mercury concentration in muktuk of the 1993 belugas has been reported (Wagemann, 1993). It was hoped, that a larger sample could be used for an age on mercury in muktuk regression (i.e. 1993 and 1994 samples combined), but ages of animals collected in 1994 were not available at the time of writing of this report.
The age-Hg relationship for belugas, based on the 1993 sample alone, is, as before, still tentative, and possibly unrepresentative of the larger population. Based on 1993 results alone, indications are that only animals > 16 years had Hg in muktuk > 0.5 µgig wet wt.
The distribution of mercury in the skin (Fig. 2), was not uniform but increased in successive strata from the inside toward the outside. It ranged in individual strata of the skin of belugas (Table 7) from 0.41 to 3.2 µgig in the outermost layer (degenerative epidermis) of different animals, and 0.31 to 2.9 µgig in the second outermost layer (stratum extemum).
The mercury concentration in each of the skin strata and in the skin as a whole were strongly, positively correlated with the age of belugas (Table 6).
Table 6. Linear regression parameters for age on mercury concentration in individual
strata of the skin and in skin as a whole (muktuk) of belugas.
Statistical Degenerative Stratum Stratum Dermis Muktuk Parameters Epidermis Externum Internum
Regr es. Coef. t 0.069 0.056 0.042 0.011 0.035
Adjusted R2 0.594 0.716 0.760 0.692 0.806
P(Regr. Coef.) 0.000 0.000 0.000 0.00 0.000
1 1 1 t units are µg ·g· -year· ; "year- " means per year of an animals life. 19
3 .0 (J'l ~ (J'l j__ 2.0 - ::r:QD
Figure 2. Mercury concentration (µg/ g wet wt) in the individual strata of the skin (degenerative epidermis, stratum extemum, stratum intermedium, dermis) of 27 belugas from the western Arctic.
The mercury concentration in blubber, < 0.25, µgig) was much lower than in the skin, as had already been reported for narwhal (Wagemann et al. 1983). In some of the belugas the two outermost layers (degenerative epidermis and stratum extemum) had approximately equal concentrations. This may have been a consequence of having harvested these animals at different stages of pre- or post-molting. Animals with a high mercury
concentration in the outermost layer (degenerative epidermis) relative to the second layer,
may have been sampled just prior to molting while animals with a relatively low mercury in 20 the outermost layer may have been sampled shortly after molting. However, in all animals the mercury concentration in the two outermost layers was consistently higher than in the innermost layer (dermis). The mercury concentrations in any two adjacent layers were
strongly, positively correlated.
Although, .the concentration of mercury in the outermost layer (degenerative
epidermis) was generally the highest, it was also the thinnest, on average 0.20 mm, and
contained only 6 % of the mercury in the skin as a whole. The second layer (stratum
extemum), on average 0.58 mm thick, contained 14 % of the total mercury in the skin. The
thickness of the stratum extemum has been reported for belugas by St. Aubin et al. (1990),
and our values are in reasonably good agreement with theirs.
The process of molting obviously does eliminate some mercury. An average-size
beluga from the western Canadian Arctic, 413 cm long (standard), having a surface area of
2 6.10 m , (average for 27 animals), would loose a minimum of 14,129 µg/year mercury
through molting (Table 7). This represented a 20 % loss of mercury annually by a beluga 21
Table 7. Mean ± standard deviation, concentration range and (n), of mercury in individual layers of beluga skin, the skin as a whole (muktuk), and muscle tissue in animals collected in 1993, physical measurements (thickness, density), and the mercury content in each layer of an animal as a whole.
Layers Thickness Density Hg Concentr. Hg Content mm g/cm3 µgig µg/animal Degener. 0.2±0.11 2.3±1.1 1.5±0.93 Epidermis (13) (13) (27) 4,319 0.1-0.5 1.3-4.9 0.41-3.2 Stratum 0.58±0.53 2.1 ±0.74 1.3±0.73 Externum (13) (13) (27) 9,810 0.2-2.2 1.0-3.4 0.31-2.9 Stratum 7.4± 1.4 1.1±0.16 1.0±0.54 Intermed. (13) (13) (27) 50,288 3.6-8.4 0.69-1.3 0.24-2.3 Dermis 4.4± 1.3 1.0±0.24 0.29±0.15 (13) (13) (27) 7,832 2.4-7 .0 0.60-1.4 0.08-0.62 Muktuk 12.5±2.7 1.1 ±0.15 0.84±0.43 72,2491 (skin as a whole) (13) (13) (27) 6.5-16.5 0.70-1.3 0.19-1.9 72,0562 Muscle Tissue 1.4±0.67 (26) 0.42-2.6
1 based on mercury concentration measurements in individual skin layers and summation. 2 based on separate concentration measurement in the skin as a whole.
(out of total of 72,056 µg of mercury in the skin of an animal as a whole). It is difficult to put this rate into perspective since rates of excretion and loss of mercury by other routes are unknown for cetaceans. The loss could be somewhat higher than was estimated because the calculated surface area used in this estimate did not include the area of flippers and flukes. 22
The estimated loss of mercury through molting is an average. For an individual, the loss would obviously differ somewhat from the mean, depending on the size and age of the individual.
Muscle
The mean total mercury concentrations in muscle of belugas from the western Arctic were relatively high in each of the four years (1981 to 1994), ranging from 1.0 to 1.4 µgig wet wt, (fable 4). Each annual mean exceeded very significantly the Canadian Government
Guideline (0.5 µgig wet wt) for consumable and exportable fish. A similarly high value
(1.31 µgig wet wt) in belugas off the Greenland ·coast was reported for > 14 years old animals (Hansen et al. 1990). Clearly, no significant change in the mercury concentration in muscle of belugas has occurred in the western Arctic since our first sampling_in 1981.
With all locations and years combined, 93 % of the animals (103 out of 111 animals), had mercury concentrations in muscle greater than 0.5 µgig wet wt, as can be seen from the frequency distribution graph for mercury in muscle (Fig. 3). Essentially the same percentage of animals (94 %; 28 out of 30 animals) exceeded this value in the smaller, 1993 sample of belugas (Wagemann, 1993). The mean mercury concentration in the animals with Hg > 0.5
µgig wet wt, for the combined sample (1981 to 1994), was 1.23 µgig wet wt, similar to the value (1.45 µgig, wet wt) obtained for the 1993 sample alone. 23
25
15
5
0.0 1.0 2.0 3.0 4.0 5.0 Hg µg / g
Figure 3. Frequency distribution of mercury concentration in muscle of belugas (111 animals) from the western Arctic.
In the combined sample (1981, 1984, 1993; no ages were available for the 1994 group), mercury in muscle of belugas was significantly, positively correlated with age,
1 1 2 (regression coefficient=0.0506 µg·g- ·year- ; R =0.616). Based on this regression analysis, animals older than approximately four years would have Hg concentrations in muscle > 0.5
µg/ g wet wt. The previously reported regression coefficient for the 1993 sample alone ·
(Wagemann, 1993) was lower and the correlation poorer (regression coefficient=0.0364;
R2 =0.330). The regression coefficient derived from the larger sample is more reliable, and indicates the average rate of mercury accumulation per year in the muscle of belugas. 24 Liver
The mean total mercury concentration in liver (Table 5) appeared to increase during
1981 to 1993, from 10.7 µgig wet wt, to 29.2 µgig wet wt, respectively, and these means differed significantly from each other. The annual means for 1984 and 1994 (17.8 and 24.4
µgig wet wt, respectively) did not differ significantly (a=0.05) from each other and other means. The higher mean concentration in the 1993 group relative to the 1981 group, although significant and based on substantial sample sizes (34 and 34 animals respectively), nevertheless, does not indicate a temporal trend. The mean age of the animals in the two groups was significantly different; 12 and 24 years for the 1981 and 1993 groups respectively
(Table 4). The difference in the mean mercury concentrations between these two groups was largely a reflection of the difference in their ages as can be seen from the similarities in the frequency distribution graphs for mercury and ages (Figs. 4 & 5). The wide range of mercury concentrations among individuals manifested itself as a pronounced tailing iri the frequency distribution graph of Hg in liver (Fig. 4). The ov:erall mean mercury concentration in liver (all locations combined) was 20.5 µgig wet wt (Table 2), which did not differ significantly from the 1993 and 1994 group means (29.2 and 24.4 µgig wet wt; Table 5). 25
45
35
~ 25
15
5
0 20 40 60 80 100 Hg µg/ g
Figure 4. Frequency distribution of mercury concentration in liver of belugas (120 animals) from the western Arctic.
28
24
20
16 ~ 12
8
4
0 0.0 20.0 30.0 40.0 Age (Years)
Figure 5. Frequency distribution of age of belugas (61 animals) from the western Arctic. 26
In the combined sample (1981 to 1993) total mercury in the liver was strongly
1 1 2 correlated with the age of animals (regression coefficient=l.229 µg·g- ·year- ; R =0.697). In the 1993 sample itself, age and total mercury were also well correlated with a similar
1 1 2 regression coefficient (regression coefficient= 1.647 µg·g- ·year- ; R =0.568). The
regression coefficient is higher for liver than for muscle, indic~ting a higher rate of mercury
accumulation per year in the liver than the muscle, resulting in a higher concentration of
mercury in the liver than the muscle. The ratio of the regression coefficients
(liver/muscle=24) does in fact roughly correspond to the concentration ratio in the two
tissues (liver/muscle= 18).
Kidney
Mercury concentrations in kidney (Table 8), were somewhat higher than in muscle
but very much lower than in liver, in accordance with the normally observed concentration
ratios in these tissues of marine mammals. The annual, mean mercury concentrations ranged
from 2.65 to 5.38 µgig wet wt (Table 8) . In the combined sample (1981 to 1994 combined)
the overall mean was 4.17 µgig wet wt (Table 2). The increase in the annual means from
1981 to 1993, and the decrease in 1994, parallels that in liver, and as for liver, these changes
do not signal temporal changes but are explicable by age differences. The mercury
concentration in the kidney was correlated with the age of animals (regression
coefficient=0.1658; R2 =0.616). The regression coefficient for kidney was somewhat higher
than that for muscle as expected on the basis of a somewhat higher concentration in kidney
than muscle. 27 Total Metals (Pb, Cd, Cu, Zn, Se)
Lead and cadmium concentrations were generally very low in muktuk, muscle and liver of western Arctic belugas. The mean lead concentration in muktuk and muscle was generally ~0.03 µgig wet wt (Tables 3 & 4), and much less than this limit in some individuals. Kidney was not analyzed for lead.
Cadmium in muktuk and muscle was also low, ~0.03 µgig wet wt (Tables 3 & 4), and frequently much less, except in 1981 belugas, which had a relatively higher cadmium concentration in muscle (0.12 µgig wet wt); even this value was still low compared to levels in liver and kidney of narwhal (Wagemann et al., 1983).
Table 8. Mean +Sd, (n) and concentration range, µgig wet wt, of metals and methyl mercury in kidney, in belugas from the western Arctic collected in 1981 to 1994.
year Pb Cd Zn Cu Se Hg CH3Hg
1981 1 8.75±3.81 22.9±4.48 2.12±0.57 2.35±0.81 2.65±1.83 35 35 35 35 35 0.67-18.7 9.04-31.0 0.87-4.64 0.92-5.16 0.21-8.89
19841 11.9±5.12 26 .7±4.02 2.40±0.24 2.82±0.62 3.66±1.57 8 8 8 8 8 6.96-21.9 22.8-35.0 2.05-2.76 2.28-4.05 2.08-7.02
1993 12.5±6.60 27.0±4.52 2.23±0.42 5.38±3.23 34 34 34 35 4.16-35.6 18.4-43 .0 1.52-3.54 0.96-13 .0
1994 8.63±2.32 26.4±4.22 2.05±0.27 4.40±2.49 46 46 46 46 3.81-13.5 17.8-35.5 1.38-2.55 1.05-13.6
§ 1981 & 1984 data are from: Wagemann et al. 1990 28
The two animals, collected in 1993, at Repulse Bay had significantly higher cadmium and lower mercury concentrations in liver and kidney (Appendix I). The Repulse Bay group consisted of only 2 animals and their ages were unknown. No general conclusions can be drawn about cadmium or other metals in tissues of belugas at Repulse Bay. Larger samples of belugas from this and other locations in the eastern Arctic are required to ·follow up on this preliminary indication of high cadmium levels. The two high cadmium values were included in the means for 1993 (Tables 5 & 8), as this did not greatly influence the grand mean (2 samples out of 34 in total).
The annual means of cadmium in the liver (Table 5) although much higher than in muscle and muktuk were relatively low and remarkably similar in all years (2.2 to 2.8 µgig wet wt). The annual means of cadmium in the kidney of western Arctic beluga were significantly higher than in the liver, but still low (8.6 to 12.5 µgig wet wt) compared to levels in narwhal (Wagemann et al., 1983). Even the highest mean was only 1/5th that of the concentration in narwhal kidney.
The mean zinc concentrations in liver, kidney, and muscle (22- 29 µgig wet wt) were
similar in all groups, whereas the mean zinc concentration in muktuk (65.5 µgig wet wt) was
approximately three times that in other tissues making muktuk seemingly a good source of
this essential element for consumers.
The mean copper concentrations varied greatly among the four tissues, being highest
in liver (12-15 µgig wet wt) and lowest in muktuk (0.5 µgig wet wt) and intermediate in
muscle and kidney (0.5-4.0 µgig wet wt). There were no significant differences in the
annual means of any of the metals except selenium. 29
Selenium mean concentrations were quite low in muscle (0.3- 0.6 µgig wet wt), much higher in muktuk (3.60 µgig wet wt), where the concentration was similar to that in the kidney (2.4-2.8 µgig wet wt). Muktuk appears to be also a good source for consumers of this essential element. The highest mean concentrations and the most variable concentrations of selenium were found in the liver (5.6-20 µgig wet wt). The selenium concentration in the liver of belugas was strongly correlated with that of mercury, as has repeatedly been shown to be the case for other marine mammals. The basis of this association has been explained
(Wagemann and Stewart, 1994). The relatively high selenium levels in the liver and their variability were dictated largely by the variability and concentration of mercury in the liver.
Kidney tissue samples from 1993 and 1994 were not analyzed for selenium. 30 References
Doidge, D.W. (1990) . Age and stage based analysis of the population dynamics of
beluga whales, Delphinapterus leucas, with particular reference to the Northern
Quebec population. PhD Thesis, Macdonald College of McGill University, Montreal,
Quebec, Canada. pp. 190 + ivx.
Hansen, C.T., Nielsen, C.O., Dietz, R. & Hansen, M.M. (1990). Zinc, cadmium, mercury,
and selenium in Minke Whales, Belugas, and Narwhals from West Greenland. Polar
Biol. 10, 529-539.
Jones, F.M. and Pfeiffer, C.J. (1994). Morphometric comparisons of the epidermis in
several cetacean species. Aquatic Mammals 20.1, 29-34.
Scheffe, H. (1959). Analysis of variance. John Wiley and Sons, New York. 477 p.
Scheffer, V.B. and A.C. Myrick, Jr. (1980) , pp. 1-51. A review of studies to 1970 of
growth layers in the teeth of marine mammals. In: W.F. Perrin and A.C. Myrick Jr
(Eds) . Age determination of toothed whales and sirenians. Reports of the International
Whaling Commission, Special Issue 3, Cambridge, England. 31
Smith, T.G., St. Aubin, D.J. & Hammill M.O. (1992). Rubbing behaviour of belugas,
Delphinapterus leucas, in a high Arctic estuary. Can. J. Zool. 70, 2405-2409.
St. Aubin, D: J., Smith, T.G. & Geraci, J.R. (1990).Seasonal epidermal molt in beluga
whales, Delphinapterus leucas. Can J. Zool. 69, 359-367.
Uthe, J.F., Solomon, J. & Grift, B. (1972). Rapid semimicro method for the determination
of methylmercury in fish tissues. JOAC 55, 583-589.
Wagemann, R. and Stewart, R.E.A. (1994). Concentrations of heavy metals and selenium in
tissues and some foods of walrus ( Odobenus rosmarus rosmarus) from the eastern
Canadian Arctic and sub-Arctic, and associations between metals, age, and gender.
Can. J. Fish. Aquat. Sci. 51, 426-436.
Wageman, R., Stewart, R.E.A., Beland, P. & Desjardins, C. (1990). Heavy metals and
selenium in tissues of beluga whales, Delphinapterus leucas, from the Canadian
Arctic and the St. Lawrence estuary. In Advances in Research on the Beluga Whale,
Delphinapterus leucas. Can. Bull. Fish. Aquat. Sci. 224, (Smith, T.G., St. Aubin,
D.J., Geraci, J.R., eds), pp.191-206. 32
Wagemann, R. (1993). Metal contaminants in muktuk of belugas and methylmercury in liver
and .muscle of belugas and ringed seals from the western Arctic. Final Report to the
Fisheries Joint Management Committee of the Inuvialuit Settlement Region. June 10,
1993. DFO, Central and Arctic Region, 501 University Crescent, Winnipeg ..
Wagemann, R., Snow, N.B., Lutz, A. & Scott, D.P. (1983). Heavy metals in tissues and
organs of the narwhal (Monodon monoceros). Can. J. Fish. Aquat. Sci. 40 (Suppl.2),
206-216. Appendix I. Means - 1993: Mean metal and methylmercury concentrations (µgig wet wt) in tissues of beluga from different locations in the western Arctic and Repulse Bay, collected in 1993.
Muscle
Site* Pb Cd Zn Cu Se Hg CH 3Hgt Mean±SD 0.010±0.005 0.02±0.002 35.1±17.7 0.56±0.08 0.35±0.10 1.56±0.49 1.65±0.50 SP n 3 3 3 3 3 3 3 Range 0.005-0.014 0.018-0.023 16.9-52.2 0.48-0.65 0.24-0.43 0.10-1.91 1.12-2.12 Mean±SD 0.008±0.009 0.01 ±0.004 27.1 ±3.93 0.68±0.08 0.29±0.04 0.89±0.71 0.83±0.61 PL n 3 3 3 3 3 3 3 Range 0.003-0.02 0.008-0.016 24.2-31.5 0.59-0.74 0.24-0.32 0.42-1.71 0.38-1.52 Mean±SD 0.002±0.002 0.03±0.03 28.4± 10.7 0.61 ±0.10 0.42±0.06 1.53±0.72 1.53±0.69 HI n 11 11 11 11 11 11 11 Range 0-0.006 0.01-0.12 19.2-49.9 0.46-0.73 0.33-0.51 0.51-2.43 0.50-2.38
Mean±SD 0.002±0.002 0.02±0.01 22.1 ±5.11 0.79±0.12 0.41 ±0.07 1.38±0.72 1.46±0.78 EWF n 13 13 13 13 13 13 13 Range 0-0.005 0.012-0.047 12.6-33.8 0.54-0.99 0.31-0.53 0.43-2.64 0.46-2.57 Mean±SD 0.004 0.086 42.6 1.16 0.44 0.66 0.55 REP n 1 1 1 1 1 1 1 Range * * * . * * * t Hg in organic solvent extract determined by AA analysis. * SP=Shingle Point; PL=Paulatuk; HI=Hendrickson Island; EWF=East Whitefish; REP=Repulse Bay.
33 Appendix I. cont'd
Liver·
Site* Pb Cd Zn Cu Se Hg CH 3Hgt Mean±SD 0.03±0.02 4.24±2.29 28.9± 1.71 16.4± 10.7 29.7± 15.7 32.1 ±23.0 1.63±0.92 SP n 5 5 5 5 5 5 5 Range 0.008-0.07 2.02-6.81 27.2-30.8 7.15-34.4 15.5-56.4 15.9-71.7 0.91-3 .14 Mean±SD 0.01±0.006 1.08±0.19 21.4±3.89 12.9±7.26 7.05±2.79 8.58± 10.0 1.16± 1.10 PL n 3 3 3 3 3 3 3 Range 0.00-0.016 0.96-1.30 17.4-25.1 8.70-21.3 4.52-10.0 2.10-20.2 0.31-2.4 Mean±SD 0.02±0.005 2.35±0.67 29 .2± 1.80 13.1 ±9.59 21.2±9.8 33.3±21.7 2.30± 1.28 HI n 11 11 11 11 11 11 11 Range 0.01-0.03 1.42-3.37 26.0-32.6 5.93-32.3 6.65-44.1 8.08-75.6 0.54-4.9
Mean±SD 0.02±0.008 2.01±1.38 24.8±7.34 6.28±2.43 19.9± 17.9 33.4±31.4 1.57± 1.04 EWF n 13 13 13 13 13 13 13 Range 0.003-0.035 0.13-5.36 10.8-38.2 1.07-8.61 1.01-55.3 0.31-99.5 0.11-3.55
Mean±SD 0.01 ±0.003 9.74±5.20 36.1±1.54 22.8± 16.6 4.83±2.06 3.43±3.09 0.65±0.06 REP n 2 2 2 2 2 2 2 Range 0.009-0.014 6.07-13.4 35.0-37.2 11.1-34.5 3.37-6.28 1.24-5.61 0.60-0.69 . t MeHg determined capillary-Ge analysis with ECO. * SP=Shingle Point; PL=Paulatuk; HI=Hendrickson Island; EWF=East Whitefish; REP=Repulse Bay.
34 Appendix I. cont'd
Kidney
Site* Pbt Cd Zn Cu set Hg CH3Hgt Mean±SD ---- 15.3±6.21 27.3±2.37 2.34±0.18 ---- 3.95± 1.44 ---- SP n 5 5 5 5 Range 7.09-21.9 24.1-30.2 2.20-2.63 2.35-5.79 Mean±SD ---- 7.30±2.93 23.4±3.04 2.07±0.33 ---- 2.61±1.19 ---- PL n 3 3 3 3 Range 4.16-9.96 19.9-25.6 1.69-2.31 1.85-3.98
Mean±SD ---- 10.2±3.05 27.4±4.36 2.18±0.31 ---- 5.69±2.42 ---- HI n 11 11 11 12 Range 5.58-15.8 18.4-33.7 1.52-2.65 2.53-11.0 Mean±SD ---- 11.3±2.58 25.8±3.2 2.10±0.34 ---- 6.87±3.93 ---- EWF n 13 13 13 13 Range 6.73-15.2 21.2-30.1 1.67-2.65 1.67-13.0
Mean±SD ---- 33.5±2.96 36.5±9.11 3.36±0.25 ---- 1.53±0.82 ---- REP n 2 2 2 2 Range 31.4-35.6 30.1-43.0 3.19-3.54 0.96-2.11
t Pb, Se, and methylmercury were not determined in kidney. * SP=Shingle Point; PL=Paulatuk; HI=Hendrickson Island; EWF=East Whitefish; REP=Repulse Bay.
35 Appendix I. cont'd
Muktuk
Site* Pb Cd Zn Cu Se Hg CH3Hgt
Mean±SD ~0.003 0.002±0.001 67.1 ±7.00 0.41 ±0.02 - 0.76±0.07 0.53 SP n 2 2 2 2 2 1 Range 0.002-0.003 62.1-72.0 0.39-0.43 0.57-0.94 ----
Mean±SD ~0.003 0.002±0.001 68.4±5.79 0.45±0.06 - 0.47±0.35 0.40±0.33 PL n 3 3 3 3 3 3 Range 0.01-0.003 62.0-73.3 0.39-0.50 0.19-0.86 0.14-0.77
Mean±SD ~0.003 0.002±0.001 66.1 ±4.56 0.46±0.10 - 0.89±0.38 0.87 ±0.38 HI n 10 10 10 10 9 9 Range 0.001-0.004 60.0-76.2 0.34-0.72 0.27-1.33 0.24-1.32
Mean±SD ~0.02 0.002±0.001 64.8±4.56 0.49±0.07 - 0.90±0.49 0.78±0.45 EWF n 13 13 13 13 13 13 Range 0.001-0.003 53.3-71.6 0.41-0.63 0.22-1.85 0.24-1.71
Mean±SD ~0.001 0.006±0.004 61.6±25.5 0.44±0.11 - 0.38±0.09 0.34±0.04 REP n 2 2 2 2 2 2 Range 0.003-0.009 43.5-79.7 0.36-0.52 0.32-0.45 0.31-0.37 t Hg determined by AA analysis of organic solvent extract. * SP=Shingle Point; PL=Paulatuk; HI=Hendrickson Island; EWF=East Whitefish; REP=Repulse Bay.
36 Appendix II. Means - 1994: Mean metal and methylmercury concentrations (µgig wet wt) in tissues of beluga from different locations in the western Arctic, collected in 1994.
Muscle
Site* Pb Cd Zn Cu Se Hg CH3Hgt
Mean±SD ~0.006 0.015±0.009 25.4±5.39 0.77±0.18 0.39±0.09 1.32±0.67 1.29±0.63 HI n 33 33 33 33 33 33 33 Range 0.005-0.053 16.4-40.4 0.47-1.34 0.24-0.66 0.43-3.44 0.42-3.16
Mean±SD ~0.003 0.015±0.005 24.1 ±3.88 0.77±0.17 0.49±0.08 1.20±0.59 1.15±0.55 EWF n 13 13 13 13 12 13 13 Range 0. 006-0. 024 15.0-28.8 0.56-1.04 0.35-0.62 • 0.41-2.24 0.35-2.00
t Hg in organic solvent extract determined by AA analysis. * HI=Hendrickson Island; EWF=East Whitefish.
Muktuk
Site* Pb Cd Zn Cu Se Hg CH3Hgt Mean±SD 3.56±0.88 0.73±0.39 0.63±0.31 HI n - - - - 33 33 33 Range 1.03-5.75 0.23-1.93 0.21-1.34
Mean±SD 3.87±0.68 0.77±0.46 0.70±0.43 EWF n - - - - 5 5 5 Range 3.27-4.92 0.30-1.30 0.24-1.24 t Hg in organic solvent extract determined by AA analysis. * HI=Hendrickson Island; EWF=East Whitefish.
37 Appendix II. cont'd
Liver
Site Pb Cd Zn Cu Se Hg CH3Hg* Mean±SD 0.012±0.007 2.44±0.85 30.3±4.28 11.9±5.64 19.0± 14.4 27.5±25.3 2.16±1.17 HI n 32 32 32 32 32 32 32 Range 0.004-0.039 1.29-4.99 24.4-46.2 5.26-31.8 5.10-58.7 4.98-116 0.70-6.13
Mean±SD 0.013±0.24 1.58±0.75 25.2±6.68 10.8±9.04 13.3±11.5 16.6± 18.2 1.38± 1.00 EWF n 11 13 13 13 13 13 13 Range < 0.001-0.077 0.15-2.34 12.0-31.9 0.81-35.1 0.72-40.9 0.47-58.5 0.17-2.88 t MeHg determined capillary-Ge analysis with ECO. * HI=Hendrickson Island; EWF=East Whitefish.
Kidney
Site* Pbt Cd Zn Cu Set Hg CH 3Hgt Mean±SD ---- 8.84±2.61 27.0±4.13 2.11 ±0.26 ---- 4.71±2.68 ---- HI n 33 33 33 33 Range 3.81-13.5 18.6-35.5 1.66-2.55 1.37-13.6 Mean±SD ---- 8.11±1.27 24.7±4.16 1.90±0.24 ---- 3.63± 1.77 ---- EWF n 13 13 13 13 Range 6.38-10.3 17 .8-31.5 1.38-2.22 1.05-7.38 t Pb, Se, methylmercury not determined in kidney. * HI= Hendrickson Island; EWF =East Whitefish.
38