ELECTRONIC SUPPLEMENTAL MATERIALESMPERTAINING TO SECTION 7
A decision framework for possible remediation of contaminated sediments in the River Kymijoki, Finland
General remediation plan (
Contents
1.Summary
2.Introduction
3.Scope and methods
4.Overview of River Kymijoki pollution
5.Overview of sediment remediation methods
Dredging methods
Stabilization methods
Capping
6.Preliminary cost-benefit analysis
Technical feasibility and cost-efficiency
Future trends in contaminant concentrations
Contaminant transport without remediation (null hypothesis)
Contaminant transport after remediation
Resuspension during remediation
Remediation risks and benefits
Remediation risks by sub regions
Summary of remediation risks by methods
Priority of remediation by sub region
7.General remediation plan
Sub region 1 (Kuusankoski-Keltti)
Preconditions for remediation
Dredging
Sludge treatment and end location
Sediment end location
Capping
Recommendation for remediation method
Sub region 2 (Keltti-Myllykoski)
Sub region 2.1
Sub region 2.2
Sub region 2.3
Sub region 2.4
Recommendation for remediation method
Sub region 3 (Myllykoski-Gulf of Finland)
Sub region 3.1
Sub region 3.2
Sub region 3.3
Recommendation for remediation method
Sub region 3.4 (Tammijärvi)
Recommendation for remediation method
Monitoring
Timing of remediation
8.Recommendations for future measures
Bibliography
Appendixes
Matrix of the combined effect of seriousness and probability for risk used in the ranking of different risks between remediation methods. For example, the deficiency of information regarding geotechnical characteristics (affecting the success of the work) was regarded as very serious with a strong possibility of risks when using the capping method within a fast flowing river and thus having ranking points of 16. This procedure was performed for each identified risk and remediation method (see the list of risks in chapter 6).
Seriousness/probability / Low1 / Harmful
2 / Serious
3 / Very serious
4
Low probability
1 / Insignificant risk
1 / Low risk
2 / Acceptable risk
3 / Moderatee risk
4
Occasional
2 / Low risk
2 / Acceptable risk
4 / Moderate risk
6 / Significant risk
8
Probable
3 / Acceptable risk
3 / Moderate risk
6 / Significant risk
8 / Severe risk
12
Strong possibility
4 / Moderate risk
4 / Significant risk
8 / Severe risk
12 / unbearable risk
16
An example of the comparison of cost efficiency between different sub regions for the dredging option including sludge treatment and sludge and sediment end location at site. A similar procedure was performed for PCDD/Fs and mercury and for dredging and capping options.
Sub region / Burden of contaminated sedimentsm3 / Costs/m3
€/m3 / Total costs
€ / Amount of PCDDF/s
kg / Cost efficiency
€/kg
Sr1 / 90,000 / 100 / 9,000,000 / 1,400 / 6,500
Sr2 / 350,000 / 100 / 35,000,000 / 1,450 / 24,200
Sr3.1 / 430,000 / 100 / 43,000,000 / 900 / 47,800
Sr3.2 / 330,000 / 100 / 33,000,000 / 370 / 89,200
Sr3.3 / 720,000 / 100 / 72,000,000 / not known / –
Sr3.4 / 2,900,000 / 100 / 290,000,000 / 1,820 / 159,400