Vah

A mass balance model of chemical fate and transport in the Váh river was used in this study to analyse the behavior of several priority pollutants, including  polycyclic aromatic hydrocarbons (PAHs), bis(2-ethylhexyl)phthalate (DEHP) and nonylphenol (NP) and factors affecting their behavior in the system of artificial water reservoirs along the river.

Concentrations and amounts of persistent chemicals such as PAHs and DEHP, are controlled by rapid advection in the river system, however, depending on the modelled river segment, more rapid sediment deposition rates reduce and retard losses by advection and increase sediment concentrations. Sediment-water exchange, primarily through particle movement, maintains chemicals in the system longer than predicted by water residence times alone. An analysis of the model indicates that the importance of sediments as a chemical source depends on the rate of permanent removal from sediments (by burial and chemical transformation), the tendency of chemical to return to the water from sediments, and the proportion of released chemical that returns to the sediments following release. These results emphasize the importance of sediment-water exchange via particle movement, even for less hydrophobic chemicals such as naphthalene or nonylphenol.
Residence time of the compounds in the sediment are up to several years in comparison to a much faster response (several days or weeks) in the water column. If loadings are reduced, the entire residence time of the system will respond substantially within several years. It can thus be argued that for these contaminants in this system there is little merit in considering dredging because natural remediation processes are would take effect in the time frame necessary for design and implementation of a remedial dredging program. The corollary to this is that if loadings are not reduced, and dredging is done, the system will recontaminate fairly rapidly to its pre-dredged condition.
Fig. 1. Location of large water reservoirs on the Váh river that were used in modelling of the fate of priority organic pollutants using QWASI model.
Updated: 2009-12-17
NEWS
2009-06-18

Project conclusions available online


General conclusions from the SOCOPSE project are now available online.  
2009-04-03

SOCOPSE Final Conference


"Future Approach to Priority and Emerging Substances in European Waters."
2009-04-03

New publications


Draft substance reports for Atrazine, Cadmium, Isoproturon, Mercury, PBDE, TBT, HCB, PAH, DEHP and...

FINANCIAL SUPPORT
Topics addressed: FP6-2005-Global-4, Topic: II. 3.1 Source control of priority substances
Project duration: 2006-2009
Contract no.: 037038
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