Spheroidal carbonaceous particles (SCPs) are derived from fossil-fuel combustion and are solely of anthropogenic origin (Rose, 1996). Since they are composed mostly of elemental carbon they are well preserved in lake sediments and are therefore excellent markers of industrial pollution. As a result, they have been used in palaeolimnological studies concerned with reconstructing the history of atmospherically deposited pollutants (Renberg & Wik,
1984; Rose et al., 1995, 1998) or human impact on a lake (Renberg et al., 1993; Bindler et al.,
2002).
Due to their characteristic morphology, SCPs are easy to distinguish from other carbonaceous particles, such as those produced by wood or grass burning (Griffin &
Goldberg, 1981). Rose et al. (1999) described SCPs in lake sediments as having diameters usually between 2-20 µm, and up to 50 µm at sites close to the source of the emission.
However, Fott et al. (1998) found that diameters of largest particles reached almost 200 µm at certain sites in the Czech Republic.
The onset of the SCP record in sediments occurs in layers dating from the early stages of industrialisation at which time there was a rapid expansion of fossil-fuel combustion
(Griffin & Goldberg, 1979, 1981; Rose et al., 1995). Where the record of industrialisation is well known, some of the main features of the SCP record (the onset, the rapid increase, the peak in concentrations and subsequent decline) have been used for sediment dating (Renberg
& Wik, 1985; Marchetto & Lami, 1994; Rose et al., 1995; Korhola & Blom, 1996) and recently also for peat dating (Chambers et al., 1999; Barber et al., 2000; Yang et al., 2001a,
2001b). SCPs in surficial lake sediments have been used for monitoring contemporary atmospheric deposition over a region (e.g., Wik & Renberg, 1991; Rose & Juggins, 1994;
Solovieva et al., 2002).
Fossil-fuel burning gives rise also to emissions of SO
2
and NO x
, gases which are the main cause of anthropogenic acidification, as well as to emissions of heavy metals and polycyclic aromatic hydrocarbons (PAHs). Since SCPs are chemically inert, their records can potentially act as a surrogate for records of other pollutants originating from fossil-fuel burning, which do not leave permanent records (Wik & Natkanski, 1990; Wik & Renberg,
1991).


In most studies on SCP palaeolimnological records, SCPs have been studied in lake sediments. In countries such as the Czech Republic where there are few natural lakes, reservoir sediments are the main potential alternative for studying records of atmospherically deposited pollutants. In many ways, however, reservoirs are more complicated systems than natural lakes (Kalff, 2002) and sedimentation processes in various reservoirs within one region are not uniform (Fott et al., 1998). With the aim to check whether reservoir sediments provide a reliable alternative to lake sediments for studies of SCP records, I have studied the spatial and temporal distribution of SCPs in sediments of Drásov Reservoir situated near the town Příbram in the central Czech
Republic.

SCPs deposit both to lakes and their catchments. Considerable input of SCPs from the catchment to a reservoir may lead to an incorrect interpretation of the SCP sediment record. With the purpose to evaluate to what extent the SCP sediment record in Drásov
Reservoir is influenced by the SCP indirect input from the reservoir catchment, I have studied inputs and sinks of SCPs in Drásov Reservoir.

Although SCP concentrations in sediments and SCP accumulation rates in sediments are widely used for determination pollution exposure of regions, these alone cannot tell anything about the scale of exposed regions, as sites can be affected by emissions from a local source. SCP size distribution in sediments could be a useful tool, which could give more information on the vicinity of the source and on the character of the SCP transport.
In order to test this hypothesis I have studied size distribution of SCPs in sediments of
Drásov Reservoir and six other sites in the Czech Republic (Fláje and Přísečnice reservoirs in the Krušné Mountains, Bedřichov and Souš reservoirs in the Jizerské
Mountains, Černé Lake in the Šumava Mountains, and a small experimental concrete pool in the centre of Prague, CU pool).
The sites for this work were chosen on the basis of a previous study (Fott et al., 1998), which shoved that they had highest SCP concentrations in surface sediments within 32 localities studied in the Czech Republic. Drásov Reservoir had the overall highest SCP concentrations in surface sediments and SCPs with greatest diameters.

1. I have studied SCP records in five sediment cores collected from different depths and along two transects in Drásov Reservoir.
2. The results suggested that wind- and inlet-induced currents had an important influence on both SCP and sediment distribution in the reservoir, and that the distribution of SCPs on the reservoir bottom was different to that of sediments (Figure 1).
20
16 sediment
SCP inventory
8
6
12
8
4
2
4
0 0
A
7 m
B
4.5 m
C
2.5 m
D
4.5 m
E
2.5 m
Figure 1.
SCP inventories and lengths of five cores taken along two transects (longitudinal transect A-
D-E and transverse transect A-B-C) from Drásov Reservoir. Cores A-C were taken in down-wind side of the reservoir near the dam. Core E was influenced by allochthonous material from the input stream.
3. Sediments in down-wind area of the reservoir provided good evidence of the history of solid emissions. Although most reliable SCP record was contained in a deep-water core (A), the records in shallower-water cores from the down-wind side of the reservoir (cores B and C) were also good (Figure 2). SCP accumulation rates in sediment correlated well with solid emissions from a local source located 3 km away from the reservoir (Spearman R = 0.87, p = 0.001). Records of emissions from individual combustion sources go back to 1982. A good representation of the history of the solid emissions by the pre-1982 SCP sediment record was confirmed by a good correlation between the SCP accumulation rate in sediment core A

from Drásov Reservoir and tariffs for exceeding the solid emission limit paid by the same combustion source in the period 1968 to 1982 (Spearman R = 0.83, p < 0.001).
0
0 core A, 7 m
SCP x 10
3
g
-1 emissions, 10
2
t y
-1
10 20
4
8
12
16
30
8
10
4
6
12
14
0
0
2 core B, 4.5 m
SCP x 10
3
g
-1
10 20 30
0
0
2
4
6
0
0
8 core D, 4.5 m
SCP x 10
3
g
-1
5 10
0
0 emissions
SCPs
2
4 core C, 2.5 m
SCP x 10
3
g
-1
10 20 30 core E, 2.5 m
SCP x 10
3
g
-1
5 10
8
4
12
6
16
8
Figure 2.
Spheroidal carbonaceous particle profiles for cores A–E from Drásov Reservoir and solid dam. Core D was taken in the middle of the reservoir, while core E approximately 160 m from the inflow.
  
4. I have studied inputs and sinks of SCPs in Drásov Reservoir during a year period
(1998/99). I have examined the atmospheric deposition of SCPs, their input into the reservoir by the tributary, the SCP concentration in the reservoir water, removal of SCPs from the reservoir water by the take-off by the water treatment plant and by the outflow, and the SCP deposition to sediment traps. Additionally, I analysed the SCP storage in two soil cores from the reservoir catchment.

5. The predominant input of SCPs into the reservoir was by the direct atmospheric deposition
(92.4 %), see Figure 3. The SCP input from the catchment by the tributary was negligible
(7.6 %). Moreover, most of SCPs brought by the tributary into the reservoir were carried in during the two periods with exceptionally high tributary discharge, when the tributary eroded soil. The predominant SCP sink from the reservoir water was by the sedimentation. Only 4 % of the total SCP input was removed from the reservoir by the take-off by the water treatment plant and by the outflow over the spillway. A similar pattern of SCP input to a lake can be expected in lowland temperate sites, which are not exposed to soil erosion. The contribution of the tributary to the SCP input to the lake will depend on the extent to which it erodes soil and to its area relative to the lake area.
30
15
10
5
25
20 no. SCPs in reservoir water atmospheric input input by tributary sink by take-off
0
.6.
.7.
.8.
27
.5.
-24
24
.6.
-22
22
.7.
-19
19
.8.
-16
.9.
.10
.
16
.9.
-14
14
.10
.-10
.11
.
10
.11
.-9.
12
.
9.
12
.-6.
1.
6.
1.
-3.
2.
3.
2.
-3.
3.
3.
.3.
.4.
3.
-31
31
.3.
-28
28
.4.
-26
.5.
Figure 3.
Total number of SCPs in the water of Drásov Reservoir, cumulative input of SCPs to the reservoir from the atmosphere and by the tributary, and cumulative SCP removal by take-off by the water treatment plant during the period May 1998 to May 1999.
6. The results suggested that in shallow water bodies with changing water level, SCP concentration in water and SCP deposition to sediments is strongly influenced by changes of the lake volume (i.e., lake depth and area) and internal movement processes within the lake.
7. The results from the sediment traps gave evidence of SCP resuspension and focusing, and supported the results from sediment core analysis, that SCPs had greater spatial variability than sediments.

8. Although forests enhance SCP deposition from the atmosphere to the catchment, these are not transported to the reservoir, as they remain in catchment soils. Catchment soils are a major store of SCPs deposited to the catchment.
  
9. I have examined SCP size distribution in surface sediments of seven sites in the Czech
Republic. Additionally, I have studied the temporal distribution of SCP sizes in a full sediment core from Drásov Reservoir.
10. The SCP size distribution revealed that two sites (Drásov Reservoir and CU pool) were influenced by local emissions, whereas SCPs at other studied sites were transported regionally
(Figure 4). The presence of SCPs with diameters over 100
 m in sediments indicates a local source of SCPs, which does not have efficient particle retention equipment. The source is not more than a few kilometres away from the site where so large SCPs occur.
50
40
30
20
10
0
Pшнseиnice
N=107
50
40
30
20
10
0
Souљ
N=217
50
40
30
20
10
0
Drбsov
N=306
<10 10-20 20-40 40-80 80-160 >160 <10 10-20 20-40 40-80 80-160 >160 <10 10-20 20-40 40-80 80-160 >160
30
20
10
0
50
40
Flбje
N=252
30
20
10
0
50
40
Bedшichov
N=423
30
20
10
0
50
40
CU pool
N=417
<10 10-20 20-40 40-80 80-160 >160 <10 10-20 20-40 40-80 80-160 >160
SCP diameters,
 m
<10 10-20 20-40 40-80 80-160 >160
SCP diameters,
 m
50
40
30
20
10
Иernй
N=257
0
<10 10-20 20-40 40-80 80-160 >160
SCP diameters,
 m
Figure 4.
SCP size distribution in surface sediments of seven sites in the Czech Republic. CU pool is a small concrete pool in Prague. Fláje and Přísečnice reservoirs are situated in the Krušné Mountains,
Bedřichov and Souš reservoirs in the Jizerské Mountains, while Drásov Resrvoir near the town
Příbram in the central Czech Republic. Černé Lake is in the Šumava Mountains.

11. A significant change occurred in the size distribution of SCPs within the vertical profile of sediment core (F) from Drásov Resrvoir (Figure 5). This c hange corresponded to a change in combustion policy by the predominant source of SCPs in the reservoir. Such a change in SCP size distribution within a sediment core can precisely indicate the age of the sediment layer in which it occurs if the source is known and the history of combustion is recorded.
0
0 10 20
SCP, %
30 40 50 60 70
2
4
6
8
< 10
 m
10-20
 m
20-100
 m
>100
 m
10
Figure 5.
Vertical profiles of several size categories of SCP diameters in sediment core F from Drásov
Reservoir.
12. The presence of large SCPs (with diameters over 40
 m) in sediments from all sites revealed that particle retention equipment of combustion sources in the Czech Republic was in an unsatisfactory condition in the early 1990s.

Barber, K. E., D. Maddy, N. Rose, A. C. Stevenson, R. Stoneman & R. Thompson, 2000.
Replicated proxy-climate signals over the last 2000 yr from two distant UK peat bogs: new evidence from regional palaeoclimate teleconnections. Quat. Sci. Rew. 19: 481-
487.
Bindler, R., T. Korsman, I. Renberg & P. Högberg, 2002. Pre-industrial atmospheric pollution: was it important for the pH of acid sensitive Swedish Lakes? Ambio 31: 460-
465.
Chambers, F. M., D. Mauquoy & P. A. Todd, 1999. Recent rise to dominance of Molinia caerulea in environmentally sensitive areas: new perspectives from palaeological data.
J. Appl. Ecol. 36: 719-733.
Fott, J., J. Vukić & N. L. Rose, 1998. The spatial distribution of characterised fly-ash particles and trace metals in lake sediments and catchment mosses: Czech Republic. Wat. Air
Soil Pollut. 106: 241-261.
Griffin, J. J. & E. D. Goldberg, 1979. Morphologies and origin of elemental carbon in the environment. Science 206: 563-565.
Griffin, J. J. & E. D. Goldberg, 1981. Sphericity as a characteristic of solids from fossil fuel burning in a Lake Michigan sediment. Geoch. Cosmoch. Acta 45: 763-769.
Kalff, J., 2002. Limnology: Inland Water Ecosystems. Prentice-Hall, Inc., Upper Saddle
River, N.J. 536 pp.
Korhola, A. & T. Blom, 1996. Marked early 20 th
century pollution and the subsequent recovery of Töölö Bay, central Helsinki, as indicated by subfossil diatom assemblage changes. Hydrobiologia 341: 169-179.
Marchetto, A. & A. Lami, 1994. Reconstruction of pH by chrisophycean scales in some lakes of the Southern Alps. Hydrobiologia 274: 83-90.
Renberg, I. & M. Wik, 1984. Dating recent lake sediments by soot particle counting. Verh. int. Ver. Limnol. 22: 712-718.
Renberg, I. & M. Wik, 1985. Soot particle counting in recent lake sediments: An indirect dating method. Ecol. Bull. 37: 53-57.
Renberg, I., T. Korsman & N. J. Anderson, 1993. A temporal perspective of lake acidification in Sweden. Ambio 22: 264-271.
Rose, N. L., 1996. Inorganic fly-ash spheres as pollution tracers. Envir. Pollut. 91: 245-252.
Rose, N. L. & S. Juggins, 1994. A spatial relationship between carbonaceous particles in lake sediments and sulphur deposition. Atmos. Envir. 28: 177-183.
Rose, N. L., S. Harlock, P. G. Appleby & R. W. Battarbee, 1995. Dating of recent lake sediments in the United Kingdom and Ireland using spheroidal carbonaceous particles
(SCP) concentration profiles. Holocene 5: 328-335.

Rose, N. L., P. G. Appleby, J. F. Boyle, A. W. Mackay & R. J. Flower, 1998. The spatial and temporal distribution of fossil-fuel derived pollutants in the sediment records of lake
Baikal, eastern Siberia. J. Paleolim. 20: 151-162.
Rose, N. L., S. Juggins & J. Watt, 1999. The characterization of carbonaceous fly-ash particles from major European fossil-fuel types and applications to environmental samples. Atmos. Envir. 33: 2699-2713.
Solovieva, N., V. J. Jones, P. G. Appleby & M. Kondratenok, 2002. Extent, environmental impact and long-term trends in atmospheric contamination in the Usa Basin of east-
European Russian Arctic. Wat. Air Soil Pollut. 139: 273-260.
Wik, M. & J. Natkanski, 1990. British and Scandinavian sediment record of carbonacelous particles from fossil-fuel combustion. Phil. Trans. R. Soc. Lond. B 327: 319-323.
Wik, M. & I. Renberg, 1991. Recent atmospheric deposition in Sweden of carbonaceous particles from fossil-fuel combustion surveyed using lake sediments. Ambio 20: 289-
292.
Yang, H., N. L. Rose & R. W. Battarbee, 2001a. Dating of recent catchment peats using spheroidal carbonaceous particle (SCP) concentration profiles with particular reference to Lochnagar, Scotland. Holocene 11: 593-597.
Yang, H., N. L. Rose, J. F. Boyle & R. W. Battarbee, 2001b. Storage and distribution of trace metals and spheroidal carbonaceous particles (SCPs) from atmospheric deposition in the catchment peats of Lochnagar, Scotland. Envir. Pollut. 115: 231-238.