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Atmospheric deposition of iron from mining activities in Northern Ontario
The Science of the Total Environment, 32 (1983) 73--79 Elsevier Science Publishers B.V., Amsterdam --Printed in The Netherlands
73
ATMOSPHERIC DEPOSITION OF IRON FROM MINING ACTIVITIES IN NORTHERN ONTARIO
WALTER A. GLOOSCHENKO
Aquatic Ecology Division, National Water Research Institute, P.O. Box 5050, Burlington, Ontario L7R 4A6 (Canada) ANNA DE BENEDETTI
Department of Chemistry, McMaster University, Hamilton, Ontario (Canada) (Received January 24th, 1983 ; accepted March 20th, 1983)
ABSTRACT Samples of Sphagnum moss were collected at varying distances from two iron-mining and processing centres in northern Ontario, Canada -- Atikokan and Sudbury -- and analyzed for Fe. All samples were collected in ombrotrophic bogs which receive chemical inputs strictly from atmospheric deposition. Mosses from the Atikokan sites exhibited elevated concentrations of Fe up to 7352 mgkg -1 near the local sources, and declined exponentially with distance to lows of 1443 mgkg -l . Atikokan, a mining and ore-processing centre, caused elevated Fe levels up to 50 km distance from the town, while Sudbury exhibited a greater influence due to the tall stack there. At Sudbury, levels ranged from 2478 mg kg -1 near the town down to 382 mgkg -1 in remote sites. Results from these moss analyses were similar to those obtained from precipitation sampling of previous authors.
INTRODUCTION M i n i n g a n d s m e l t i n g a c t i v i t i e s in n o r t h e r n areas c a n r e s u l t in t h e a t m o s pheric transport and subsequent deposition of potentially toxic elements s u c h as m e t a l s , a r s e n i c , a n d s e l e n i u m . In s u c h a r e a s , m o n i t o r i n g o f d e p o s i t i o n of these substances can be d o n e by analysis of lower vegetation collected at various distances from sources. F o r example, trace metal emissions f r o m t h e S u d b u r y , O n t a r i o m i n i n g a n d s m e l t i n g c o m p l e x was m o n i t o r e d using S p h a g n u m m o s s , l i c h e n s , a n d h i g h e r p l a n t s b y G l o o s c h e n k o e t al. ( 1 9 8 1 ) w h i l e As was m e a s u r e d b y A r a f a t a n d G l o o s c h e n k o ( 1 9 8 2 ) in b o g v e g e t a t i o n . In t h e s a m e a r e a , l i c h e n s w e r e u s e d t o m e a s u r e m e t a l d e p o s i t i o n b y N i e b o e r et al. ( 1 9 7 2 ) a n d T o m a s s i n i e t al. {1976). L i c h e n s a n d m o s s e s w e r e also u s e d t o m e a s u r e a e r i a l i n p u t o f m e t a l s f r o m t h e u r a n i u m m i n i n g in n o r t h e r n O n t a r i o b y N i e b o e r et al. ( 1 9 8 2 ) .
0048-9697/83/$03.00
© 1983 Elsevier Science Publishers B.V.
74 The present study was conducted to determine the atmospheric deposition of iron from two mining areas in northern Ontario -- Atikokan and Sudbury -- by use of Sphagnum moss. Atikokan was chosen as it is the site of an iron mining and pelletizing complex using the iron ores goethite and hematite. Mining activities ceased there in 1979 (Canadian Mineral Survey, 1979). Sudbury is still active utilizing magnetite and pyrrhotite ores for iron production (Canadian Mineral Survey, 1981).
METHODS A total of 11 bogs were sampled along Highway 17 both east and west of Atikokan, Ontario, during July 1982 (Fig. 1). Sphagnum moss, mainly S. fuscum, was collected by hand using disposable gloves to prevent contamination; only the living portions of the moss were collected. The samples were placed in plastic bags and kept cool at 4--5°C for 4 8 h until they were returned to the laboratory where they were frozen until analyzed. Samples were then thawed, dried in an oven at 95°C for 4 8 h , and ground in a Wiley mill to 60 mesh. The samples were wet-ashed with a nitric--perchloric acid mixture and Fe determined by atomic absorption s p e c t r o p h o t o m e t r y at a wavelength of 372 nm. The Sudbury sites are the same as those reported by Glooschenko et al. (1981); iron was n o t discussed in the previous study.
RESULTS The results of iron analyses of mosses from the Atikokan, Ontario samples are shown in Fig. 2. In general, iron levels in Sphagnum were 7352 m g k g -1
Ontario
11 ~_...L,~..L
~
10
Fort -"~. Frances < "~1
Atikokanml f"" ~L
~
~
5 6
1f/------~"-4--/" Quetico Provincial
0
20
40
60
~
~
~
,
~ _ I i
I
~ 8
80
Kilometers
"~
"~ I~
~ ~
~
Thunder Bay
Fig. 1. Map showing sampling site locations in Atikokan, Ontario mining area.
.
75 8000-
7000 6000E
5000-
0
40000 0
i
30002000-
1000-
0
10
210
3(3
4~0
5~0
610
7'0
80
90
Distance from Atikokan,km Fig. 2. I r o n c o n t e n t o f Sphagnum fuscum in r e l a t i o n t o d i s t a n c e f r o m A t i k o k a n , O n t a r i o .
at a bog located 8 km SSE of the mining facilities; however, levels decreased with distance from the mine site. The five sites b e y o n d 50 km were similar and had a mean of 1 6 4 4 + 8 0 m g k g -1. Thus, at Atikokan, a fairly local influence within 40--50 km was observed in terms of iron deposition. Sudbury appears to have a much greater influence (Fig. 3). A high of 2 4 7 8 m g k g -1 was f o u n d in Sphagnum sampled in a bog 1 8 k m from the stack; iron levels were elevated up to distances of 200--250 km from the site. Beyond 250 km, levels averaged 464 mg kg- 1.
DISCUSSION
The iron data of this study are compared with others from Sphagnum determined in investigations both in North America and Europe (Table 1). Previous data from areas remote from industrial sources include those from Kinoje Lake bogs in the Hudson Bay Lowland (Glooschenko and Capobianco, 1978), the Northwest Territories of Canada (Pakarinen and Tolonen, 1976; Glooschenko and Capobianco, 1978), northern Finland (Pakarinen and Tolonen, 1976), and Minnesota (Gotham and Tilton, 1978). These data should represent an approximate Fe baseline in Sphagnum for remote areas
76 3000-
O~ .ag
2000-
._g ¢0 0
== t o o o -
•
S
(,9
0
100
200 300 Distance from Sudbury, km
400
Fig. 3. Iron content of Sphagnum fuscum in relation to distance from Sudbury, Ontario. and give a mean Fe level o f 4 3 3 m g k g -1 with a standard error of 73. Thus, this c o n c e n t r a t i o n serves as a rough guide to natural levels and higher concentrations would indicate anthropogenic enrichment. The highest previously r e p o r t e d c o n c e n t r a t i o n was 4182 mg kg -1 in the Adirondack Mountains o f New York State, U.S.A., an area subject to atmospheric deposition f r o m heavy industrialization (Furr et al., 1979). The Sphagnum Fe concent r a t i ons in t he Atikokan area were higher than any r e p o r t e d previously in the literature, and directly related to atmospheric deposition related to iron ore mining and processing activities. Even the lower co n cen tr at i ons o f Fe (average of 1644 +80 mg kg -1 at points greater than 50 km) are quite high c o m p a r e d to o t h e r r e p o r t e d values. These can be a t t r i b u t e d to factors o t h e r than the influence of the activities at Atikokan. These sites are close t o t he iron ore deposits south of the area in the State o f Minnesota, U.S.A. G or ha m and Tilton (1978) analyzed Sphagnum fuscum f r o m various sites in Minnesota and f o u n d values o f Fe ranging f r o m 240 to 1 0 4 0 m g k g -1. Highest values were in western Minnesota which t h e y a t t r i b u t e d to dustfall f r o m the Great Plains area. The nearest site to our study was f o u n d in t he B oundar y Waters Canoe Area adjacent t o the U.S.A-Canadian border in which a value of 360 mg kg-' was obtained, approximately one-fifth of our mean values at sites f u r t h e r f r o m Atikokan. A study o f various metals in precipitation in Minnesota was made by T h o r n t o n and Eisenreich (1982). Similar to G o t h a m and Tilton's results (1978), t h e y
77 TABLE 1 IRON CONCENTRATIONS IN SPHAGNUMMOSSES FROM OTHER GEOGRAPHIC AREAS Location
Source of data
Fe concentration (rag kg- I )
Atikokan, Ont. Sudbury, Ont. Kinoje Lake Hudson Bay Lowland, Ont. Porter Lake, N.W.T.
This study This study Glooschenko and Capobianco (1978) Glooschenko and Capobianco (1978) Pakarinen and Tolonen (1976)
1 4 4 3 - 7 3 5 2 , ~ = 3276 382--2478,~ = 1052 269
Furr et al. (1979)
4182
Pakarinen and Tolonen (1976) Rtihling and Tyler (1971) Gotham and Tilton (1978) Glooschenko and Arafat (1982) Unpublished data
231/401 890--2880, ~ -- 1416 240--1040, ~ -- 581 679--2784, ~ -- 1445
Great Slave Lake, Edmonton, Alberta Adirondack Mtns. New York State, U.S.A. Finland, North/South Sweden, Southern Minnesota Rouyn--Noranda, Quebec
1002 82,84/546
f o u n d h i g h e s t d e p o s i t i o n o f Fe in t h e w e s t e r n p o r t i o n o f t h e s t a t e w h e n c o m p a r e d t o t h e e a s t e r n region a d j a c e n t to o u r s t u d y area. H o w e v e r , we c a n n o t r e j e c t t h e p o s s i b i l i t y t h a t s o m e o f t h e iron in o u r m o s s e s was d u e t o d e p o s i t i o n f r o m i r o n m i n i n g activities in t h e s o u t h o f M i n n e s o t a . Also, t h e C a n a d i a n Shield r o c k s in t h e area t e n d t o be higher in Fe w h i c h c o u l d also lead t o e l e v a t e d i r o n in local m o s s e s f r o m n a t u r a l dustfall. S u d b u r y a p p e a r s t o have a g r e a t e r i n f l u e n c e o n a t m o s p h e r i c d e p o s i t i o n o f Fe, p r o b a b l y d u e t o its high s t a c k leading t o d e p o s i t i o n o f p a r t i c u l a t e debris at g r e a t e r distances. Y e t levels o f Fe in Sphagnum mosses d o n o t a p p r o a c h t h o s e f o u n d in t h e A t i k o k a n area. Studies h a v e b e e n m a d e o f Fe in lichens in t h e S u d b u r y area b y N i e b o e r et al. ( 1 9 7 2 ) a n d T o m a s s i n i et al. ( 1 9 7 6 ) . T h e first s t u d y s h o w e d a five- t o six-fold d e c r e a s e o f Fe in lichens at sites 48 k m f r o m t h e s m e l t e r , while t h e s e c o n d s t u d y i n d i c a t e d a decrease o f Fe in a lichen, Stereocaulon paschale, f r o m 5 2 0 0 m g kg -1 at 8.1 k m dist a n c e d o w n t o 2 0 1 0 m g k g -1 at 4 8 . 6 k m distance. In o u r s t u d y , we f o u n d a d e c r e a s e f r o m 2 4 7 8 m g k g -1 in m o s s e s 1 8 k m f r o m t h e s m e l t e r , t o 1 1 9 0 a n d 2 1 3 0 m g kg -1 at t w o sites 85 k m a w a y . T h e g r e a t e r value was in Sphagnum s a m p l e d f r o m a hill s o m e 40 m higher t h a n t h e o t h e r site. A similar diff e r e n c e in c o n c e n t r a t i o n was f o u n d in As in t h e t w o bogs ( A r a f a t a n d Glooschenko, 1982). In o r d e r t o c o n v e r t m o s s c o n c e n t r a t i o n s t o d e p o s i t i o n rate, o n e m u s t k n o w t h e n e t a n n u a l p r i m a r y p r o d u c t i o n o f m o s s e s a n d m u l t i p l y this b y t h e tissue c o n c e n t r a t i o n a s s u m i n g little leaching or t r a n s l o c a t i o n ( P a k a r i n e n a n d T o l o n e n , 1 9 7 6 ) . U n f o r t u n a t e l y , n o d a t a are available f o r m o s s p r i m a r y p r o d u c t i o n in e i t h e r o f o u r t w o areas. R e a d e r a n d S t e w a r t ( 1 9 7 1 ) r e p o r t
78 a value o f 1 7 g m - : y -1 ( a s s u m i n g 100% cover) o f Sphagnum fuscum in M a n i t o b a while P a k a r i n e n a n d T o l o n e n ( 1 9 7 6 ) e s t i m a t e 4 0 0 g m - 2 y -1 f o r Sphagnum in Finland. If we use each o f t h e s e values a n d m u l t i p l y t h e m b y t h e Fe c o n c e n t r a t i o n i n Sphagnum f o r S u d b u r y , 2 4 7 8 m g kg -1, a low a n d high value o f t h e Fe d e p o s i t i o n r a t e o f 42 a n d 991 g m -2 y-1 are c a l c u l a t e d . J e f f r i e s a n d S n y d e r ( 1 9 8 1 ) d e t e r m i n e d Fe b u l k d e p o s i t i o n r a t e s in t h e S u d b u r y area o f 1 0 1 - 3 6 5 m g m - 2 y -1 using p r e c i p i t a t i o n s a m p l i n g m e t h o d s ; Muller a n d K r a m e r ( 1 9 7 7 ) r e p o r t e d 1 8 3 m g m - 2 y -1 in t h e s a m e area. T h u s , o u r e s t i m a t e d range o f Fe d e p o s i t i o n , using m o s s analyses, is w i t h i n t h e s a m e o r d e r o f m a g n i t u d e as was f o u n d in t h e t w o studies using p r e c i p i t a t i o n m e a s u r e m e n t s . We d o n o t have Fe d a t a f o r p r e c i p i t a t i o n at A t i k o k a n , O n t a r i o f o r a similar c a l c u l a t i o n . We have s h o w n t h a t m i n i n g a n d o r e - p r o c e s s i n g activities are an i m p o r t a n t s o u r c e o f Fe t o t h e a t m o s p h e r e a n d t h e u t i l i t y o f using m o s s e s to e s t i m a t e t h e a t m o s p h e r i c d e p o s i t i o n o f Fe f r o m such sources. When d a t a are available f o r m o s s n e t p r i m a r y p r o d u c t i o n , such c o n c e n t r a t i o n d a t a m a y be c o n v e r t e d t o a t m o s p h e r i c d e p o s i t i o n r a t e s increasing t h e u t i l i t y o f such an a p p r o a c h to environmental monitoring.
ACKNOWLEDGEMENTS T h e a u t h o r s wish t o t h a n k M. G r e g o r y a n d T. M a y e r f o r t h e i r assistance in m o s s analysis. R. Sims a n d M. Siltanen are t h a n k e d f o r assistance in field sampling. N. H a r p e r is t h a n k e d f o r h e r critical r e v i e w o f t h e m a n u s c r i p t a n d J. M c G r e g o r f o r her t y p i n g .
REFERENCES Arafat, N. M. and W. A. Glooschenko, 1982. The use of bog vegetation as an indicator of atmospheric deposition of arsenic in northern Ontario. Environ. Pollut. (Series B), 4: 85--90.
Canadian Mineral Survey, 1979: Can. Dept. Energy, Mines, and Resources, 52--53. Canadian Mineral Survey, 1 9 8 1 . Can. Dept. Energy, Mines, and Resources, 5 6 - - 5 8 . Furr, A. K., C. L. Schofield, M. C. Grandolfo, R. A. Hofstader, W. H. Gutenmann, L. E. St. John, Jr. and D. J. Lisk, 1979. Element content of mosses as possible indicators of air pollution. Arch. Environm. Contam. Toxicol., 8: 335--343. Glooschenko, W. A. and J. A. Capobianco, 1978. Metal content of Sphagnum mosses f r o m two northern Canadian bog ecosystems. Water Air Soil Pollut., 10: 215--220. Glooschenko, W. A., R. Sims, M. Gregory and T. Mayer, 1981. The use of bog vegetation as a m o n i t o r o f atmospheric input of metals. In: S. Eisenreich (Ed.), Atmospheric Input of Pollutants to National Waters, Ann Arbor Science, Ann Arbor, MI, pp. 389-399. G o r h a m , E. and D. L. Tilton, 1978. The mineral content of Sphagnum fuscum as affected by human settlement. Can. J. Bot., 56: 2755--2759. Jeffries, D. S. and W. R. Snyder, 1981. Atmospheric deposition of heavy metals in central Ontario. Water Air Soil Pollut., 15: 127--152.
79 Muller, E. F. and J. R. Kramer, 1977. Precipitation scavenging in central and northern Ontario. In: R.G. Semonin and R.W. Beadle (Eds.), Precipitation Scavenging (1974), Proc. Sympos., Tech. Info. Center, Energy Res. and Devel. Admin., Champaign, IL, pp. 590--601. Nieboer, E., H. M. Ahmed, K. J. Puckett and D. H. S. Richardson, 1972. Heavy metal content of lichens in relation to distance from a nickel smelter in Sudbury, Ontario. Lichenologist, 5: 292--304. Nieboer, E., D. H. S. Richardson, L. J. R. Boileau, P. J. Beckett, P. Lavoie and D. Padovan, 1981. Lichens and mosses as monitors of industrial activity associated with uranium mining in northern Ontario, Canada. Part 3: Accumulations of iron and titanium and their mutual dependence. Environ. Pollut. (Series B), 4: 181--192. Pakarinen, P. and K. Tolonen, 1976. Regional survey of heavy metals in peat mosses (Sphagnum). Ambio, 5: 38--40. Reader, R. J. and J. M. Stewart, 1971. Net primary productivity of bog vegetation in southeastern Manitoba. Can. J. Bot., 49: 1471--1477. Rtihling, A. and G. Tyler, 1971. Regional differences in the deposition of heavy metals over Scandinavia. J. Appl. Ecol., 8: 497--507. Rtihling, A. and G. Tyler, 1973. Heavy metal deposition in Scandinavia. Water Air Soil Pollut., 2 : 445--455. Thornton, J. D. and S. J. Eisenreich, 1982. Impact of land use on the acid and trace element composition of precipitation in the north central U.S. Atmos. Environ., 16: 1945--1955. Tomassini, F.D., K.J. Puckett, E. Nieboer, D.H.S. Richardson and B. Grace, 1976. Determination of copper, iron, nickel, and sulfur by X-ray fluorescence in lichens from the Mackenzie Valley, Northwest Territories, and the Sudbury district, Ontario. Can. J. Bot., 54: 1591--1603.
73
ATMOSPHERIC DEPOSITION OF IRON FROM MINING ACTIVITIES IN NORTHERN ONTARIO
WALTER A. GLOOSCHENKO
Aquatic Ecology Division, National Water Research Institute, P.O. Box 5050, Burlington, Ontario L7R 4A6 (Canada) ANNA DE BENEDETTI
Department of Chemistry, McMaster University, Hamilton, Ontario (Canada) (Received January 24th, 1983 ; accepted March 20th, 1983)
ABSTRACT Samples of Sphagnum moss were collected at varying distances from two iron-mining and processing centres in northern Ontario, Canada -- Atikokan and Sudbury -- and analyzed for Fe. All samples were collected in ombrotrophic bogs which receive chemical inputs strictly from atmospheric deposition. Mosses from the Atikokan sites exhibited elevated concentrations of Fe up to 7352 mgkg -1 near the local sources, and declined exponentially with distance to lows of 1443 mgkg -l . Atikokan, a mining and ore-processing centre, caused elevated Fe levels up to 50 km distance from the town, while Sudbury exhibited a greater influence due to the tall stack there. At Sudbury, levels ranged from 2478 mg kg -1 near the town down to 382 mgkg -1 in remote sites. Results from these moss analyses were similar to those obtained from precipitation sampling of previous authors.
INTRODUCTION M i n i n g a n d s m e l t i n g a c t i v i t i e s in n o r t h e r n areas c a n r e s u l t in t h e a t m o s pheric transport and subsequent deposition of potentially toxic elements s u c h as m e t a l s , a r s e n i c , a n d s e l e n i u m . In s u c h a r e a s , m o n i t o r i n g o f d e p o s i t i o n of these substances can be d o n e by analysis of lower vegetation collected at various distances from sources. F o r example, trace metal emissions f r o m t h e S u d b u r y , O n t a r i o m i n i n g a n d s m e l t i n g c o m p l e x was m o n i t o r e d using S p h a g n u m m o s s , l i c h e n s , a n d h i g h e r p l a n t s b y G l o o s c h e n k o e t al. ( 1 9 8 1 ) w h i l e As was m e a s u r e d b y A r a f a t a n d G l o o s c h e n k o ( 1 9 8 2 ) in b o g v e g e t a t i o n . In t h e s a m e a r e a , l i c h e n s w e r e u s e d t o m e a s u r e m e t a l d e p o s i t i o n b y N i e b o e r et al. ( 1 9 7 2 ) a n d T o m a s s i n i e t al. {1976). L i c h e n s a n d m o s s e s w e r e also u s e d t o m e a s u r e a e r i a l i n p u t o f m e t a l s f r o m t h e u r a n i u m m i n i n g in n o r t h e r n O n t a r i o b y N i e b o e r et al. ( 1 9 8 2 ) .
0048-9697/83/$03.00
© 1983 Elsevier Science Publishers B.V.
74 The present study was conducted to determine the atmospheric deposition of iron from two mining areas in northern Ontario -- Atikokan and Sudbury -- by use of Sphagnum moss. Atikokan was chosen as it is the site of an iron mining and pelletizing complex using the iron ores goethite and hematite. Mining activities ceased there in 1979 (Canadian Mineral Survey, 1979). Sudbury is still active utilizing magnetite and pyrrhotite ores for iron production (Canadian Mineral Survey, 1981).
METHODS A total of 11 bogs were sampled along Highway 17 both east and west of Atikokan, Ontario, during July 1982 (Fig. 1). Sphagnum moss, mainly S. fuscum, was collected by hand using disposable gloves to prevent contamination; only the living portions of the moss were collected. The samples were placed in plastic bags and kept cool at 4--5°C for 4 8 h until they were returned to the laboratory where they were frozen until analyzed. Samples were then thawed, dried in an oven at 95°C for 4 8 h , and ground in a Wiley mill to 60 mesh. The samples were wet-ashed with a nitric--perchloric acid mixture and Fe determined by atomic absorption s p e c t r o p h o t o m e t r y at a wavelength of 372 nm. The Sudbury sites are the same as those reported by Glooschenko et al. (1981); iron was n o t discussed in the previous study.
RESULTS The results of iron analyses of mosses from the Atikokan, Ontario samples are shown in Fig. 2. In general, iron levels in Sphagnum were 7352 m g k g -1
Ontario
11 ~_...L,~..L
~
10
Fort -"~. Frances < "~1
Atikokanml f"" ~L
~
~
5 6
1f/------~"-4--/" Quetico Provincial
0
20
40
60
~
~
~
,
~ _ I i
I
~ 8
80
Kilometers
"~
"~ I~
~ ~
~
Thunder Bay
Fig. 1. Map showing sampling site locations in Atikokan, Ontario mining area.
.
75 8000-
7000 6000E
5000-
0
40000 0
i
30002000-
1000-
0
10
210
3(3
4~0
5~0
610
7'0
80
90
Distance from Atikokan,km Fig. 2. I r o n c o n t e n t o f Sphagnum fuscum in r e l a t i o n t o d i s t a n c e f r o m A t i k o k a n , O n t a r i o .
at a bog located 8 km SSE of the mining facilities; however, levels decreased with distance from the mine site. The five sites b e y o n d 50 km were similar and had a mean of 1 6 4 4 + 8 0 m g k g -1. Thus, at Atikokan, a fairly local influence within 40--50 km was observed in terms of iron deposition. Sudbury appears to have a much greater influence (Fig. 3). A high of 2 4 7 8 m g k g -1 was f o u n d in Sphagnum sampled in a bog 1 8 k m from the stack; iron levels were elevated up to distances of 200--250 km from the site. Beyond 250 km, levels averaged 464 mg kg- 1.
DISCUSSION
The iron data of this study are compared with others from Sphagnum determined in investigations both in North America and Europe (Table 1). Previous data from areas remote from industrial sources include those from Kinoje Lake bogs in the Hudson Bay Lowland (Glooschenko and Capobianco, 1978), the Northwest Territories of Canada (Pakarinen and Tolonen, 1976; Glooschenko and Capobianco, 1978), northern Finland (Pakarinen and Tolonen, 1976), and Minnesota (Gotham and Tilton, 1978). These data should represent an approximate Fe baseline in Sphagnum for remote areas
76 3000-
O~ .ag
2000-
._g ¢0 0
== t o o o -
•
S
(,9
0
100
200 300 Distance from Sudbury, km
400
Fig. 3. Iron content of Sphagnum fuscum in relation to distance from Sudbury, Ontario. and give a mean Fe level o f 4 3 3 m g k g -1 with a standard error of 73. Thus, this c o n c e n t r a t i o n serves as a rough guide to natural levels and higher concentrations would indicate anthropogenic enrichment. The highest previously r e p o r t e d c o n c e n t r a t i o n was 4182 mg kg -1 in the Adirondack Mountains o f New York State, U.S.A., an area subject to atmospheric deposition f r o m heavy industrialization (Furr et al., 1979). The Sphagnum Fe concent r a t i ons in t he Atikokan area were higher than any r e p o r t e d previously in the literature, and directly related to atmospheric deposition related to iron ore mining and processing activities. Even the lower co n cen tr at i ons o f Fe (average of 1644 +80 mg kg -1 at points greater than 50 km) are quite high c o m p a r e d to o t h e r r e p o r t e d values. These can be a t t r i b u t e d to factors o t h e r than the influence of the activities at Atikokan. These sites are close t o t he iron ore deposits south of the area in the State o f Minnesota, U.S.A. G or ha m and Tilton (1978) analyzed Sphagnum fuscum f r o m various sites in Minnesota and f o u n d values o f Fe ranging f r o m 240 to 1 0 4 0 m g k g -1. Highest values were in western Minnesota which t h e y a t t r i b u t e d to dustfall f r o m the Great Plains area. The nearest site to our study was f o u n d in t he B oundar y Waters Canoe Area adjacent t o the U.S.A-Canadian border in which a value of 360 mg kg-' was obtained, approximately one-fifth of our mean values at sites f u r t h e r f r o m Atikokan. A study o f various metals in precipitation in Minnesota was made by T h o r n t o n and Eisenreich (1982). Similar to G o t h a m and Tilton's results (1978), t h e y
77 TABLE 1 IRON CONCENTRATIONS IN SPHAGNUMMOSSES FROM OTHER GEOGRAPHIC AREAS Location
Source of data
Fe concentration (rag kg- I )
Atikokan, Ont. Sudbury, Ont. Kinoje Lake Hudson Bay Lowland, Ont. Porter Lake, N.W.T.
This study This study Glooschenko and Capobianco (1978) Glooschenko and Capobianco (1978) Pakarinen and Tolonen (1976)
1 4 4 3 - 7 3 5 2 , ~ = 3276 382--2478,~ = 1052 269
Furr et al. (1979)
4182
Pakarinen and Tolonen (1976) Rtihling and Tyler (1971) Gotham and Tilton (1978) Glooschenko and Arafat (1982) Unpublished data
231/401 890--2880, ~ -- 1416 240--1040, ~ -- 581 679--2784, ~ -- 1445
Great Slave Lake, Edmonton, Alberta Adirondack Mtns. New York State, U.S.A. Finland, North/South Sweden, Southern Minnesota Rouyn--Noranda, Quebec
1002 82,84/546
f o u n d h i g h e s t d e p o s i t i o n o f Fe in t h e w e s t e r n p o r t i o n o f t h e s t a t e w h e n c o m p a r e d t o t h e e a s t e r n region a d j a c e n t to o u r s t u d y area. H o w e v e r , we c a n n o t r e j e c t t h e p o s s i b i l i t y t h a t s o m e o f t h e iron in o u r m o s s e s was d u e t o d e p o s i t i o n f r o m i r o n m i n i n g activities in t h e s o u t h o f M i n n e s o t a . Also, t h e C a n a d i a n Shield r o c k s in t h e area t e n d t o be higher in Fe w h i c h c o u l d also lead t o e l e v a t e d i r o n in local m o s s e s f r o m n a t u r a l dustfall. S u d b u r y a p p e a r s t o have a g r e a t e r i n f l u e n c e o n a t m o s p h e r i c d e p o s i t i o n o f Fe, p r o b a b l y d u e t o its high s t a c k leading t o d e p o s i t i o n o f p a r t i c u l a t e debris at g r e a t e r distances. Y e t levels o f Fe in Sphagnum mosses d o n o t a p p r o a c h t h o s e f o u n d in t h e A t i k o k a n area. Studies h a v e b e e n m a d e o f Fe in lichens in t h e S u d b u r y area b y N i e b o e r et al. ( 1 9 7 2 ) a n d T o m a s s i n i et al. ( 1 9 7 6 ) . T h e first s t u d y s h o w e d a five- t o six-fold d e c r e a s e o f Fe in lichens at sites 48 k m f r o m t h e s m e l t e r , while t h e s e c o n d s t u d y i n d i c a t e d a decrease o f Fe in a lichen, Stereocaulon paschale, f r o m 5 2 0 0 m g kg -1 at 8.1 k m dist a n c e d o w n t o 2 0 1 0 m g k g -1 at 4 8 . 6 k m distance. In o u r s t u d y , we f o u n d a d e c r e a s e f r o m 2 4 7 8 m g k g -1 in m o s s e s 1 8 k m f r o m t h e s m e l t e r , t o 1 1 9 0 a n d 2 1 3 0 m g kg -1 at t w o sites 85 k m a w a y . T h e g r e a t e r value was in Sphagnum s a m p l e d f r o m a hill s o m e 40 m higher t h a n t h e o t h e r site. A similar diff e r e n c e in c o n c e n t r a t i o n was f o u n d in As in t h e t w o bogs ( A r a f a t a n d Glooschenko, 1982). In o r d e r t o c o n v e r t m o s s c o n c e n t r a t i o n s t o d e p o s i t i o n rate, o n e m u s t k n o w t h e n e t a n n u a l p r i m a r y p r o d u c t i o n o f m o s s e s a n d m u l t i p l y this b y t h e tissue c o n c e n t r a t i o n a s s u m i n g little leaching or t r a n s l o c a t i o n ( P a k a r i n e n a n d T o l o n e n , 1 9 7 6 ) . U n f o r t u n a t e l y , n o d a t a are available f o r m o s s p r i m a r y p r o d u c t i o n in e i t h e r o f o u r t w o areas. R e a d e r a n d S t e w a r t ( 1 9 7 1 ) r e p o r t
78 a value o f 1 7 g m - : y -1 ( a s s u m i n g 100% cover) o f Sphagnum fuscum in M a n i t o b a while P a k a r i n e n a n d T o l o n e n ( 1 9 7 6 ) e s t i m a t e 4 0 0 g m - 2 y -1 f o r Sphagnum in Finland. If we use each o f t h e s e values a n d m u l t i p l y t h e m b y t h e Fe c o n c e n t r a t i o n i n Sphagnum f o r S u d b u r y , 2 4 7 8 m g kg -1, a low a n d high value o f t h e Fe d e p o s i t i o n r a t e o f 42 a n d 991 g m -2 y-1 are c a l c u l a t e d . J e f f r i e s a n d S n y d e r ( 1 9 8 1 ) d e t e r m i n e d Fe b u l k d e p o s i t i o n r a t e s in t h e S u d b u r y area o f 1 0 1 - 3 6 5 m g m - 2 y -1 using p r e c i p i t a t i o n s a m p l i n g m e t h o d s ; Muller a n d K r a m e r ( 1 9 7 7 ) r e p o r t e d 1 8 3 m g m - 2 y -1 in t h e s a m e area. T h u s , o u r e s t i m a t e d range o f Fe d e p o s i t i o n , using m o s s analyses, is w i t h i n t h e s a m e o r d e r o f m a g n i t u d e as was f o u n d in t h e t w o studies using p r e c i p i t a t i o n m e a s u r e m e n t s . We d o n o t have Fe d a t a f o r p r e c i p i t a t i o n at A t i k o k a n , O n t a r i o f o r a similar c a l c u l a t i o n . We have s h o w n t h a t m i n i n g a n d o r e - p r o c e s s i n g activities are an i m p o r t a n t s o u r c e o f Fe t o t h e a t m o s p h e r e a n d t h e u t i l i t y o f using m o s s e s to e s t i m a t e t h e a t m o s p h e r i c d e p o s i t i o n o f Fe f r o m such sources. When d a t a are available f o r m o s s n e t p r i m a r y p r o d u c t i o n , such c o n c e n t r a t i o n d a t a m a y be c o n v e r t e d t o a t m o s p h e r i c d e p o s i t i o n r a t e s increasing t h e u t i l i t y o f such an a p p r o a c h to environmental monitoring.
ACKNOWLEDGEMENTS T h e a u t h o r s wish t o t h a n k M. G r e g o r y a n d T. M a y e r f o r t h e i r assistance in m o s s analysis. R. Sims a n d M. Siltanen are t h a n k e d f o r assistance in field sampling. N. H a r p e r is t h a n k e d f o r h e r critical r e v i e w o f t h e m a n u s c r i p t a n d J. M c G r e g o r f o r her t y p i n g .
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