FROM SOIL POLLUTION TO A RISK BASED SOLUTION

Transcription

1 FROM SOIL POLLUTION TO A RISK BASED SOLUTION Joop Harmsen International Conference Protection of soil functions challenges for the future 15th 18th October 2013, Puławy, Poland

2 How do give contaminated sites in de world a proper function

3 How to solve contamination problems in Benin Benin, Oganla Parathion methyl Benin, Djassin Dieldrin

4 Willingness to pay Amsterdam Western Gas Factory Photos: Markus, Swart Benin, Djassin Dieldrin Sednet

5 Traditional approach Suspected site (Problem) Sampling and analysis Assessment Insufficient or not Compare with target values the proper data Human and ecological risks Solution Logistic problems Sampling Analysis Logistic problems Distance Costs Removal of soil (depot) Treatment on special sites (technological approach) Covering, In-Situ (technological approach) Not available costs

6 The assessment circle Problem Local possibilities Reduction of risks It s too expensive to solve Yes, there is a problem Risk Assessment Common sense Risk based data Bioavailability

7 Basic elements of Reduction of Risks African approach Bioavailability Prevent direct contact Common sense Local possibilities

8 Bioavailability individual physical, chemical, and biological interactions that determine the exposure of plants and animals to chemicals associated with soils and sediment (National Research Council, 2003). soil/water Chemical measurements (available fractions) membrane organism Toxicity tests Biological measurements Specifically, bioavailability addresses the fact that only a fraction of the contaminant concentration present in the environment may be taken up or result in an effect on an organism! Bioaccumulation ISO 17402

9 Situation in Better understanding Bioavailable part is causing risks Bioavailable part can be measured (Guideline, ISO 17402; Use of extracts for trace elements, ISO 14858) Actual available (concentration in pore water) Trace elements (0.001 M CaCl 2 ISO ) POP s (Passive sampling) Potential available (amount in equilibrium with pore water, reactive fraction) Trace elements (0.43 M HNO 3, ISO 17586) POP s (Tenax; Cyclodextrine, ISO ) Models on fate of contaminants include availability

10 How can bioavailability make a difference? If contaminants are not physically accessible, or chemically or biologically available, they should not be included in the calculation of risk Can optimize the extent of cleanup required to be protective Can provide optimization of remedial approach and cost Can be an important factor in balancing the risks caused by remedial action

11 Common sense: Which risks are present? volatilization Risks are site specific Field observations Monitoring to confirm Run-off/erosion Soil surface Physical contact Contaminated soil leaching

12 Local conditions Risks are reduced if local conditions: Stimulate biodegradation Reduce bioavailability Isolate the contaminant physically Investigate in the field (observation, common sense)

13 PAH (mg/kg d.m.) Biodegradation of PAHs, removal of risks measured fit predicted passive landfarm C C t F fast Tenax 20 C k e fast Tenax 60 C t F slow Time (years) e k slow t F very slow e k very slow t

14 Application of this knowledge Create situations were PAHs degradation will continue Agricultural function Combination with energy crop Creation of temporary depot Improve local conditions (vegetation, ground water level)

15 Degradability of pesticides Pesticide DT 50 in Soil (d) Pesticide DT 50 in Soil (d) Degradable Methamidophos rapidly Aldrin Monocrotophos Captafol 3-55 Paraquat 8-12 Carbaryl 7-28 Parathion ethyl rapidly Chlordimeform Parathion methyl rapidly Chlorpyrifos ethyl Pentachlorophenol rapidly Chlorvinvos Phenthoate rapidly Chlorbenzilate Phosalone 1-4 Cyanophos Phosphamidon Cyhalothrin Propoxur Deltamethrin Pyridaphenthion Diazinon ,4,5,T Dimetheoate Tetrachlorvinphos 2 Dinoseb 5-31 Endosulfan (alpha) 60 NOT or difficult degradable Fenitrothion Chlordan >1500 Fenthion 34 DDT >1500 Fenvalerate Dieldrin > 2500 Fluoracetamide 50 Endosulfan (beta) >800 α-hch 140 Endrin >1500 Heptachlor 250 β-hch >500 Lamdacyhalothine 6-40 Hexachlorobenzene >1500 Malathion 4-6 γ-hch (Lindane) >500 Mancozeb 1-7 Toxaphene >2500

16 Create proper conditions to degrade parathion ethyl (Molodo, Mali) Soil treatment Vegetation Japtropha Biological activity, compost Vetiver Role vegetation Increase bioactivity in rooted area Evaporation Excess of rain Prevent Access

17 Results degradation parathion ethyl July 16, 2008 November 11, 2008 Parathion-ethyl Dieldrin Ratio Parathion-ethyl Dieldrin Ratio g/kg d.m. g/kg d.m. g/kg d.m. g/kg d.m < <0.025 Average Biodegradation of Parathion methyl on Oganla Site, Benin?

18 Risk of heavy metals in a sediment depot Filling of depot Ripening Reuse depot

19 CaCl2/Aqua regia Without management of depots risks by Cd Sulphides present in sediments will oxidise 2FeS + 4 1/2 O 2 + 2H 2 0 -> Fe 2 O SO H + ph will drop Mobile fraction Cd increases Cadmium ph

20 ph Cd mg/kg d.s. Cd ug/l Cadmium in 3 depots 1 Total Actual available A 1B A 2B A 3B A R Ld 1B Ld 2B Ld 3B Ld R G 1B G 2B G 3B G 1R 0.0 A 1B A 2B A 3B A R Ld 1B Ld 2B Ld 3B Ld R G 1B G 2B G 3B G 1R depot r e f e r e n c e Preconditions for agricultural function Decrease of actual bioavailability 4.5 Compensate for ph drop (Liming) Allowable maximum for 3 Cd ph A 1B A 2B A 3B A R Ld 1B Ld 2B Ld 3B Ld R G 1B G 2B G 3B G 1R

21 Development of strategies to immobilize PFOS PFOS Perfluoroctane sulfonate (fire fighting agent), persistant compound, not biodegardable Development of modified natural material with capacity to immobilize PFOS Investigation of bioavailability of PFOS in treated soils.

22 Application of MatCARETM

23 PFOS biobeschikbaarheid, Darwin

24 Isolation, prevent contact and decrease leaching Dieldrin contamination Middle of nowhere Partly covered with sand dunes Removal not an option ($ ) Risks Direct contact Transport to groundwater Cover Stabilization Evaporation of rainfall Fence vegetation, non consumable, Vetiver, Jatropha Define use Mauretania,Ledfatar

25 Isolation, prevent contact and decrease leaching Vegetation to stabilize the cover Ledfatar, 2009 Clean soil Original soil Non-degradable pesticides Nonpermeable layer

26 Increase adsorption (non degradable POP s) Black carbon (soot, activated carbon.) increases adsorption Dieldrin contamination in Mali (Africa) OM is low (high temperture) Char coal is locally available Use for isolation in depot

27 Conclusions On many contaminated sites it is necessary to break the assessment circle to give the site a function Tools are: Bioavailability Prevent direct contact Common sense Local possibilities Risks can be reduced by using: Stimulation of biodegradation Reduction of bioavailability Isolation of the contaminant Regulatory and public acceptance????

28 Sustainable >> Remediation Social-cultural aspects Social justice Appeal Human size Sustainability Societal functionality Environmental aspects- spatial diversity Economical aspects

29 Thank you for your attention