curriculum in natural environmental science, vol. 2, 2010NEAR
Institute of Water Supply and Environmental ProtectionCracow University of TechnologyKrakow, ul. Warszawska 24, 31-155 Poland
Reservoirs as a trap for pollutants
Ewa Szalinska
Krakow University of Technology, Krakow, Poland
Outline:
• Reservoirs as traps for sediments• Consequences of sediments trapping• Risk related to the contaminated sediments
• Case study: Czorsztyn Reservoir
Reservoirs as traps for sediments• “The ultimate destiny of all reservoirs is to be filled
with sediment” (Linsley et al. 1992)
Source: www.usace.army.mil
• Trap efficiency – around 80-90%
Sediment as sink for contaminants
Sediment properties:• fine fraction• clays • organic C• cation exchange
capacity• pH
Processes :
• adsorption
• absorption
• ion-exchange
• Co-precipitation
• complexation
• chelation
Consequences of sediments trapping
• Loss of the reservoir volume• Accumulation of sediment-associated
contaminants• Major contaminants of sediments:
– Nutrients – Bulk Organics – Halogenated Hydrocarbons or Persistent Organics– Polycyclic Aromatic Hydrocarbons (PAHs)– Metals
Risk related to the contaminated sediments
• Possibly toxic for the invertebrates and fish• Sediment-associated contaminants can be
bioaccumulated• Direct exposure for humans• Impaired human uses
Source: McDonald & Ingersoll 2002
Case study: Czorsztyn Reservoir
Photo: T. Zabrzewski
Localization
Map source: http://www.zzw-niedzica.com.pl/; Photos: E. Szalinska
Monometallic contamination in the sampling area
300 local tanneries
Cr as a tanning agent
Map source: http://www.zzw-niedzica.com.pl/; Photo: E. Szalinska
Temporal distribution of Cr in the upper Dunajec River sediments (2000-01)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Nov-00 Dec-00 Jan-01 Mar-01 May-01 Oct-01 Nov-01
Cr
[mg
/g d
ry w
.]
Sampling site 1 Sampling site 2
Source: Szalinska et al. 2003
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Sampling site 1 Sampling site 2 Sampling site 3 Sampling site 4
Cr
[mg/
g dr
y w
.]Spatial distribution of Cr in the upper
Dunajec River sediments (2000-01)
Source: Szalinska et al. 2003
Conceptual schema of Cr transport in the Dunajec-Czorsztyn system
After Dominik et al. 2007
River Reservoir
dissolved Cr
particulate Cr(III)
Cr(III) adsorption
coagulationsedim
entation
settling aggregates
HMWC
LMWC
aggr
egat
ion
colloids
Cr(VI)
precipitation poly-Cr(OH)3
Source: Wachałowicz, unpublish.
Spatial distribution of Cr in the Czorsztyn Reservoir sediments (2006)
0,1300,012
0,120
1 %
13,8 %
Chromium Organic matter
Source: Wachałowicz, unpublish.
Spatial distribution of Cr and organic matter in the Czorsztyn Reservoir sediments (2006)
Source: Szalinska et al., in prep.
Budget of Cr for the Czorsztyn Reservoir
• Lack of precise data about Cr discharges;• Cr load estimated on the basis of WWTP data and
water sampling results;• Suspended matter as a vector in the Cr transport
(93 Kt/yr)• Total Cr load calculate with use of partition
coefficient Kd (84 t/yr)
Further reading:• Benett & Rhoton 2007. Reservoir Sedimentation and Environmental
Degradation. Assessing Trends in Sediment-Associated Trace Elements in Grenada Lake, Mississippi. J Environ Qual. 36:815-825
• Dominik et al. 2007. Speciation and environmental fate of chromium in rivers contaminated with tannery effluents. Engineering in Life Sciences, 7(2):155-169.
• MacDonald & Ingersoll 2002. A guidance manual to support the assessment of contaminated sediments in freshwater ecosystems. EPA-905-B02-001-A.
• Metre & Mahler 2004. Contaminant trends in reservoir sediment cores as records of influent stream quality. Environ. Sci. Technol., 38:2978-2986
• Pye (ed) 1994. Sediment transport and depositional Processes. Blackwell Scientific Publications
• Sundborg A. 1992. Lake and reservoir sedimentation. Prediction and interpretation. Geogr. Ann. 74A:93-100
• Szalinska et al. 2003. Fate of tannery chromium contamination in a stream: Temporal and spatial evolution of chromium(III) and chromium(VI). J. Physics IV, 107:1275-1278
