Potential environmental risks from
sediment-bound trace elements:
A case study from the Ukrainian part of the
Danube Delta
Davide Vignati1 and Nikolai Berlinsky2
1) Istituto di Ricerca Sulle Acque – Consiglio Nazionale delle Ricerche,
Brugherio (Milan), Italy
2) Odessa State Environmental University, Odessa, Ukraine
NEAR

curriculum in natural environmental science, vol. 2, 2010
Summary
• Sediments are sinks for contaminants
• Dredging works can remobilize contaminants
• Dredging works in Danube Delta in May 2004
• How to evaluate potential metal toxicity?
Sampling sites (dredging May 2004)
The Danube basin (1)
The sampling area and dredging sites
The Danube delta (2)
1) From Wikimedia commons. Public Domain, created by the United States Federal Government
2) From Wikimedia commons. Public Domain; created by NASA
Evaluation of potential toxicity
TEC = Threshold Effect Concentration
PEC = Probable Effect Concentration
< TEC =
Element
concentrations
< TEC =
> PEC
> PEC =
Concentrations vs. TEC and PEC in Danube
Concentration (mg/kg)
Copper
Site number
Concentrations vs. TEC and PEC in Danube
Concentration (mg/kg)
Lead
Site number
Concentrations vs. TEC and PEC in Danube
Concentration (mg/kg)
Mercury
Site number
Concentrations vs. TEC and PEC in Danube
Concentration (mg/kg)
Arsenic
Site number
Conclusions and questions for discussion
• Exceedance of TECs (PECs) occurs
– Biological effects?
– Combined metal effects (see main text)
– Seasonal variability?
– Hydrological variability?
• Biological investigations needed
– Laboratory tests?
– Field studies?
• Some sediments may pose risks to biota