environmental and technical aspects of pcb disposal
TRANSCRIPT
Katarína DercováLaboratory of Environmental BiotechnologyInstitute of BiotechnologyFaculty of Chemical and Food TechnologySlovak University of Technology, Bratislava
Environmental and Technical Aspects of PCB Disposal, Properties, Monitoring, Destruction, and
Remediation of PCB-contaminated sites
„Non-Combustion Demonstration Project in Slovakia“
Regional Training Workshop on PCBs and POPs Wastes, Bratislava, Slovakia, December 1- 4,, 2009
Outline of the presentation
International Commitments on POPs
The fate of PCBs in the environment
History of the PCB production in Slovakia; Characterization of PCB-contaminated areas - „old environmental burdens“;
Non-Combustion Demonstration Project in Slovakia – a current effort to remediate PCB-polluted areas in accordance with Stockholm Convention on POPs; Problems and solutions
PCB destruction technologies – some promising non-combustion physico-chemical and biological remediation technologies – principles, advantages, and limitations
Conclusions
POPs (PCBs) – serious ecological problemslow degradabilityhigh hydrophobicitylow water solubilityhigh lipid solubilitybioaccumulation in biota
high toxicity semi-volatilityhigh sorption capacitylow chemical reactivityhigh chemical stabilitypersistence in the environment
Due to migration of POPs at long-range distances from their original source, it is necessary to deal with the release of POPs to the environment at multinational level
International Conventions:
Stockholm Convention on POPs Basel Protocol on Long-range Transboundary Air Pollution
Slovakia – party to the international commitments
Basic assessment of „dirty dozen“global production
A Dioxins 10,5 tB PCBs 1.5 mil. tC HCB 1-2 mil. tD Mirex (no data avail.)E Chlordan 70,000 tF DDT 2,8-3 mil. t
G Aldrin 240,000 tH Dieldrin 240,000 tI Endrin 3,12 mil. t
J Toxafen 1,33 mil. tK Heptachlor 900 t
Stockholm Convention requires from the signatories to take measures for source elimination of 12 „old“ and 9 „new“ substances
belonging to POPs including PCBs Safe destruction of PCBs by the year 2010 is required
from the EU member states including Slovakia!
PCBs• 31% - escaped
into the environment
• 65% - still being used in closed
systems
• 4% - disposed in incinerators
C12H10-(x+y)Clx+y x + y = 1 – 10 chlorines
209 PCB congeners
2. PCBs
Clx Clypara
meta
meta
ortho ortho
ortho ortho
meta
meta
para4'
6' 5'
23 2' 3'
4
5 6
Undiserable effects on human health:chloracne, liver diseases, reproduction anomalies, carcinogenesis, neurotoxicity, estrogenic effects – imitators and blockers of hormones – PCBs are considered „endocrine disruptors“
The fate of PCBs in the environment - controlled by a combination of interacting processes classified as:physical – responsible for movement of PCBs away from their sourcechemical and biological – determine the extent to which PCBs will be transformed. Transformations occur abiotically or biotically (by MO).PCBs – the most hydrophobic anthropogenic (man-made) compounds!Decachlorobiphenyl has 108 times higher affinity to lipid than to water compartment!
Cl
ClClCl
ClCl
Cl
ClCl
Cl
zrkadlový obrazPCBs - Atropoisomeric compounds (enantiomers)
Clm
Cln
former producerChemko StrážskeProduction: 21,500 tons
Slovakia belonged to the 8 largest world PCB-producer
3. History of PCB Production3. History of PCB Production
About 50% of production -exported; 50% used in the territory of former Czechoslovakia (today Czech and Slovak Republic)
PCB Manufacture in Slovakia1959 - 1984
Year
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
0200400600800
100012001400160018002000
PCB production (tons)
Cl m
Cl n
n = 1 - 5 m = 0 - 5
APIROLIO (Italy) AROCLOR (U.K., U.S.A.) ASBESTOL (U.S.A) ASKAREL (U.K., U.S.A.) BAKOLA 131 (U.S.A.) CHLOREXTOL (U.S.A.) CLOPHEN (Germany) DELOR, DELOTHERM, HYDELOR (Czechoslovakia) DK (Italy) (Factory Chemko Strážske)DIACLOR (U.S.A.) DYKANOL (U.S.A.) ELEMEX (U.S.A.) FENCLOR (Italy) HYDOL (U.S.A.) INTERTEEN (U.S.A.) KANECLOR (Japan) NOFLAMOL (U.S.A.) PHENOCLOR (France) PYRALENE (France) PYRANOL (U.S.A.) PYROCLOR (U.K.) SAFT-KUHL (U.S.A.) SOVOL (U.S.S.R.) SOVTOL (U.S.S.R.)
PCB commercial mixtures brand names:
Commercial mixtures of PCBslow dielectric constant, high boiling point, good fire resistance, good ageing properties with no deteriorationin service make them ideal for use as:
Delor 103 ~ Aroclor 1242
Dielectric & insulating fluidsDelor 106 ~ Aroclor 1260
Synthetic paint additives, plasticizersDelotherm
Heat exchanger fluids
HydelorHydraulic fluids
capacitors
transformers
1.5-20 kg PCBs
OPEN SYSTEMS (prohibited)CLOSED SYSTEMS (still can be used)
600 tons PCB wastes from production (semi-solid residues from former production – hardly manipulable material of a semifluid consistence – biphenyls and terphenyls)
1,500 tons PCB-containing equipment – at present, there are registered: 400 pieces of transformers, 30,000 pieces of capacitors, and 400 pieces of other equipment
1,500 tons various wastes - stockpiles of contaminated hydraulic and transformer oils with PCB contents, scraps of PCB–dyes...at Pláne waste dump (in the vicinity of the former producer) -additional 900 tons of PCBs from production
Inventory of PCB stockpiles –current existence of ∑3.600 tons
Storage of the unused PCB products
Solid PCB distillation residues with expected high dioxin level
Barrel corrosion and drums with biphenyls and terphenyls
Chemko FactoryChemko Factory
Laborec River
Strazske TownStrazske Town
„Environmental Burdens“Hot spot and urgent problem in Slovakia
0
100
200
300
400
500
600
ng/g
fat
Braz
il Fiji
Phili
ppin
esAu
stra
liaHu
ngar
yNe
w Zea
land
Bulg
aria
Chin
aUS
AIre
land
Finl
and
Egyp
tNo
rway
Croa
tiaUk
rain
eRu
ssia
Swed
enRo
man
iaNe
ther
land
sBe
lgiu
m
Germ
any
Luxe
mbo
urg
Spai
nIta
ly Sl
ovak
Rep
.Cz
ech
Rep.
Holoubek, Recetox (2006)
PCB levels in the human population
The number of indicator-PCBs: (28, 52, 101, 138, 153, 180) in mother milk (Holoubek, 2006)
NRC-Diox / IPCM
1The former producer Chemko Strážske2 The former producer´s effluent canal3 Laborec River4 Inflow canal (for ZŠ)5 Zemplínska šírava water reservoir6 Outflow canal
5 km long
33.5 km2
(Kočan et al., 2007)
• An essential, integral and dynamic part of the hydrological system• Important source of nutrients – application to soil• Ultimate reservoir for the chemical and biological contaminants – the
potential to pose ecological and human health risks• Several hundred tons of PCBs have been released into the environment -
hydrophobic properties - PCBs tend to be adsorbed by the aqueous sediment - an abundant PCB source causing contamination of the waters of Eastern Slovakia
Contaminated sediments
PCBs in sedimentsEffluent canal: 1 – 10 g/kg of sed.d.w.
Laborec River: 0.1 - 1 g/kg
Zemplínska Šírava: 0.001 - 0.1 g/kg
Effluent canalLaborec River
Zemplínska Šíravawater reservoir
Initial approximation assumes: 40,000 tons of PCB-contaminated sediments
8,5
2400
6000
3900
1600
Domasa Lake
Zemplinska Sirava Lake
Filling canal (for ZS)
Laborec / downstream Strážske
Sewage canal / Strážske town
Chemko effluent canal
ppb (dry sediment)
Polluted Area
Control Area
PCB Levels in Sediment Samplespolluted area vs control area
3 000 000 = 0.3 % 3-5 kg/t of dry mud!
2.4 mg/kg
0.008 mg/kg
(Kočan et al.)
224
375
1,5
5,2
Planktonophage+benthic
Predatory
Planktonophage+benthic
Predatory
ppm (sum of all congeners, lipid weight)
Stropkov –control waters
Michalovce - polluted waters
PCB Levels in FishPolluted waters vs Control waters
(Kočan et al., 1998)
„Goldfish“ 15-220-fold content of PCBs compared to the rest of Slovakia
Consumption of fish is banned for future 25 years!
4. „NON-COMBUSTION PROJECT"Global Program
„Demonstration of Viability and Removal of Barriers that Impede Adoption and Effective
Implementation of Available, Non-combustion Technologies for Destroying
Persistent Organic Pollutants“
Non-Com project
0500
10001500200025003000350040004500
Slovakia Philippines China Africancountry
PCB equipmentPCB wastesPOPs PesticidesContaminated soil
targeted wastes
NigeriaNigeria
Non-Com project
Project Objective
supply of high-tech non-combustion technology for disposal of chlorinated substances, namely
polychlorinated biphenyls and chlorinated obsolete pesticides
The following facilities will be provided by the grant:1. technological unit for PCB destruction
(PCBs from liquid and bulk solids) 2. extraction unit
(PCB extraction of solid matrix - sediments and soils)
Non-Com project
Project structureThe project is realized by the attendance of the following subjects:
Donator organization – GEF (Global Environmental Facility - financing organization)Implementing agency - UNDP (United Nations Development Programme)Executive agency - UNIDO (United Nations Industrial DevelopmentOrganization)
Slovak partners are: Ministry of the Environment of SR (MoE SR), Public Sector Consortium (Kosice Self-governing Region, the town of Michalovce, the town of Strazske and the Slovakian Hydro-economic enterprise) Private Sector Consortium (company Chemko a.s. and local Slovak Non-Governmental Organizations)
Project scheduleProject will last six years (72 months)
The first 24 months – would involve tendering process, obtaining necessary operating permits, impact analyses; designing, constructing and testing technology to be deployed; planning and organizing comprehensive public participation, involvement monitoring, and evaluation plan.
The next 18 months – would involve actual destruction of 600 tons of PCB contaminated product, targeted stockpile and waste residues from the formal PCB production; another 400 tons of PCB waste will be collected from the PCB waste owners; implementation of broadly based public participation and involvement plan, and initiation of the rigorous monitoring and evaluation plan.
Following 30 months would involve destruction of 1,500 tons of PCB waste from the state sector and contaminated equipment owners in Slovakia and activities related to the destruction of PCB concentrate from decontamination activities of highly contaminated sediments and soil.
The last 6 months would be committed to the comprehensive assessment of overall project results, including lessons learned and the definition of concrete mechanisms for successful replication at the regional and global levels, and the technology transfer process.
• Preparatory phase
• Technology performance
• Results dissimination activities
Proposal for Financial AssuranceTotal expenses of the project are proposed to 20,155,040 USD and
represents following items:
TOTAL GEF 10,004,040.- USD
Cofinancing SRGovernment of SR represented by MoE SR 2,000,000.- USDPublic sector consortium 1,000,000.- USDPrivate sector consortium 6,121,000.- USD
(including 2,00,000 USD guaranteed by MoE as payments of PCB waste and equipment holders for disposal at non-combustion unit)
TOTAL SR 9,121,000.- USD
Cofinancing otherUNIDO 665,000.- USDUNDP 95,000.- USDNon-governmental organizations 270,000.- USDTOTAL other 1,030,000.- USD
TOTAL COFINANCING 10,151,000.- USD
TOTAL EXPENSIES OF THE PROJECT 20,155,040.- USD
„Non-Combustion Project
Selection of Project technology
Final selection of technology was realized through transparent, two-step international tendering process in accordance with UNIDO Financial Rules and Regulations and Procurement Manual within the project realization.Potentially appropriate types of technologies tentatively identified by TAG (Technical Advisory Group) documents were these best over-elaborate technologies:GPCR – Gas Phase Chemical ReductionBCD – Base Catalyzed Decomposition Solvated Electron Technology – reaction in flowing electrons mediumSodium Reduction – reduction by dispersive sodium in mineral oil
Non-Com project
Non-Com project
5. Available technologies for destruction of POPs (PCBs)
1) High temperature destruction - combustion or non-combustion technologies (plasm arc, pyrolysis,molten salt oxidation)2) Oxidative non-combustion technologies -supercritical water oxidation, catalytic oxidation, mediated electrochemical oxidation3) Reductive technologies - dehalogenation or reduction4) Photolytic destruction technologies5) Biological technologies – Bioremediation and Phytoremediation (economical and ecological alternative of physico-chemical methods) for remediation of PCB-contaminated sites
Non-Com project
Non-Combustion Technologies- Selection Criteria (highlights)
Operate in systems that are essentially closedHigh total destruction efficiencies (DEs)Available non-combustion technologies has to meet the
Stockholm Convention requirements to ensure the use of Best Available Techniques (BAT) and ensure Best Environmental Practices (BEP)
Suitable for the matrices specific for the countryTechnologies that are already commercially available
Non-Com project
Advantages of non-combustion technologies
Intrinsically low environmental impact
Mobility and scalability
Diversity - can be adjusted for a variety of applications
Products can be re-usableTechnically Environmentally Economically feasible sollutions for POPs destruction
CxHyClxOz + H2 CH4 + H2O + HCl(> 850 °C)
CH4 + H2O 3 H2 + CO (steam reforming, catalytic)CO + H2O CO2 + H2 (water-gas shift, catalytic)
CxHyClxOz + H2 CH4 + H2O + HCl(> 850 °C)
CH4 + H2O 3 H2 + CO (steam reforming, catalytic)CO + H2O CO2 + H2 (water-gas shift, catalytic)
GPCR(Gas Phase Chemical Reduction)
Advantages Excellent DE99.9999 %
Low amounts of solid residuesAll types of wastes, mobility,
scalabilityAll emissions and residues may
be captured for assay and re-processing
Limitations, disadvantagesComplexity
Safety issue related to hydrogenCostly for low strength wastes
or small scales
GPCR involves the reduction of organic compounds by hydrogen and some steam (which acts as a heater transfer agent and another source of hydrogen) at temperature of 850°C or greater. Organic compounds (POPs) are ultimately reduced to methane, hydrogen chloride (if the waste is chlorinated), and minor amounts of low molecular weight hydrocarbons (benzene and ethylene). Water shift reaction - improve decomposition.
The hydrochloric acid is neutralized by addition of caustic soda during initial cooling of the process gas, or can be taken off in acid form for reuse.Cooled, scrubbed gas from the reactor is compressed, analyzed, and re-used as a fuel for plant components.
Gas-Phase Chemical ReductionTM
Block Flow DiagramGas-Phase Chemical ReductionTM
Block Flow Diagram
Liquid Waste PreheaterSystem (LWPS)
TORBEDTM ReactorSystem
Thermal Reduction Batch Processor (TRBP)
Gas-PhaseChemicalReduction(CPCRTM)Reactor
Gas ScrubbingSystem
Product GasCompression and
Storage
Contaminated
Liquids
Contaminated
Solid/Sediment
Contaminated
Bulk Solids
Clean Solids Clean Water
Gas
Liquid
Solid
AuxiliaryBurner
Rec
ircu
lati
on
Gas
Fuel
for
Fro
nt -
end
S yst
ems
Front-end units differ depending on the waste matrix
I. II. III.
Technology can be broken down into 3 basic unit operations:The front-end system (where the contaminants are rendered into a suitable form for destruction in the reactor), the reactor ( which reduces the contaminants, now in gas phase using hydrogen and steam), and the gas scrubbing and compression system.
Liquid and solid wastes are placed into TRBP (Thermal Reduction Batch Processor), heated to 600°C in a hydrogen-rich (oxygen deficient) atmosphereContaminants that volatilise off of the solids and liquids are then swept into the GPCR reactor for destruction.
Experience:Australia, Japan, Canada, USA
Described as non-conventional heterogeneous catalytic hydrogenation process in which PCBs react with an alkali metal hydroxide, a hydrogen donor and a proprietary catalyst to produce salts, water and carbonaceous residue. When heated to about 300°C, the reagent produces highly reactive atomic hydrogen, which cleaves chemical bonds that confer toxicity to compounds.Oil and catalyst may be recovered for re-use.
currently operates in CzR
BCD (Base Catalyzed Decomposition)RCl + NaOH + [H] RH + NaCl + H2O
(catalyst, T = > 320°C, nitrogen blanketing)[H] is the hydrogen donor
RCl + NaOH + [H] RH + NaCl + H2O(catalyst, T = > 320°C, nitrogen blanketing)
[H] is the hydrogen donor
Na Na+ + e- (in liquid NH3)RCl + Na+ R+ + NaCl, NaNH2, R+ …
Na Na+ + e- (in liquid NH3)RCl + Na+ R+ + NaCl, NaNH2, R+ …
AdvantagesNo formation of dioxins/furans
No data emissions was identifiedMobile units and multiple capacities
Applicable to soils, solids, liquids, transformers, capacitors
Limitations, disadvantagesDewatering needed prior to treatment
Use of sodium requires precautions Ammonia useHigh pressure
Licensing: USA
SET (Solvated Electron Technology)
Solvated electron solutions are produced by dissolving sodium metal in anhydrous ammonia at room temperature. The solvated electrons reduce PCBs to sodium chloride, sodium amide, and petroleum hydrocarbons. Materials with a high water content must be de-watered prior to treatment.
Alkali Metal ReductionSodium Reduction Technology
Treatment of wastes with dispersed metallic alkali in mineral oil. Metallic alkali reacts with chlorine to produce salt and non-halogenated wastePCB destruction reaction by-products include:SODIUM CHLORIDE (table salt that could be used in industrial processes or road ice melting agent)POLYPHENYL (hydrocarbon without chlorine that could be used as a clean fuel in industrial furnaces) SODIUM HYDROXIDE (common chemical used in industry) MINERAL OIL (re-usable transformer oil)
RH10-x Clx + Na NaCl + RH10-xClx-1
RH10-x Clx + H RH10-x+1Clx-1
Efficacy: < 2 ppm – for treated oil; PCB < 0.5 ppm; dioxins < 1 ppb for solid residues.
Applicability: PCBs to 10 000 ppm
Recommended for Slovakia:
Pure PCBs
KINECTRICS (R&D Division of Ontario Hydro, Canada)
Sodium ReductionPCB contaminated oilOther POPs
PCBcontaminated electrical
equipmentSolvent extraction
PCB contaminated soil
Thermal desorption
Concentrated PCB residues
Concentrated PCB residues
Clean oil can be re-used in electrical transformers
NaCl, NaOH,
Petroleum based
byproduct
Complete PCB destruction
Process operates at atmospheric pressure and temperature between 90 – 165 °C.Treatment can take place either in situ or ex situ
Process diagram:
Alkali-Metal-Reduction
Process Flow Schedule in Canada (fixed plant)
North America, Germany, France, Spain, Iran, Japan
Commercialized variation: Sodium Powder Dispersion Process (Japan, Okayama 2002)
Non-Com project
Oil flows from a feed tank to the processing unit and then to a treated oil tankOn-line treatment:oil flows from atransformer unit to–processing unit and then to transformer unit
Used widely for removal of PCBs from transformers.
Plant Toyota CityFirst foreign PCB destruction technology approved in Japan
BioremediationWhat is bioremediation?
Returning the environment to its original state using biological processes
Bioremediation can be defined as any process that uses microorganisms (mainly bacteria), fungi, green plants or their enzymes to return the
environment altered by contaminants to its original condition, to transform toxic compounds
to less toxic or non-toxic intermediatesTotal decomposition of POPs to carbon dioxide, water, and
biomass is called mineralization
C l
C l
O 2
oxygenase
H O H O H
H
C l
C l
dehydrogenase
-H 2
O H O H
H
H
C l
C l
dioxygenase
O 2
C l
O C O O H
O H C l
hydrolase C l
C O O H
I II III IV V
.
Aerobic degradation of PCBsUpper catabolic pathway
Chlorobenzoic acid -
- Accumulation or degradation to CO2 and
H2O
BDO
bphA bphB bphC
Meta-cleavageproduct2,3-dihydroxybiphenyl
biphenyl-cis-2,3-dihydrodiol
PCBs
bphD+2-
hydroxy-penta-
2,4-dienic acid
2-hydroxy-6-oxo-6-phenylhexa-2,4-dienic acid
C l
C l
O 2
oxygenase
H O H O H
H
C l
C l
dehydrogenase
-H 2
O H O H
H
H
C l
C l
dioxygenase
O 2
C l
O C O O H
O H C l
hydrolase C l
C O O H
I II III IV V
bphA bphB bphC
Meta-cleavageproduct2,3-dihydroxybiphenyl
biphenyl-cis-2,3-dihydrodiol
PCBs
bphD+2-
hydroxy-penta-
2,4-dienoic
acid
Most of the PCB-degrading bacteria do not have the completegenetic information for „upper“ and „lower“ metabolic pathways!
Isolation (or construction) of microorganisms with high degradation and survival potential –
the essential assumption of successful bioremediation technology!
„Upper“ catabolicpathway
„Lower“ catabolicpathway
biphenyldioxygenase
Strategies for bioremediationBiostimulation – nutrients (N, P) and oxygen are added to encourage the growth and activity of indigenous microbial consortium (bacteria) already existing in the soil or water Bioaugmentation - adapted or designed (GMO) microorganisms that can
clean-up a particular contaminant are added to the contaminated soil or water in order to supplement the indigenous microbial population and to accelerate degradation of target compoundsIntrinsic bioremediation – natural attenuation, occurs naturally, requires close monitoring of contaminant degradation to ensure that environment and human health are protected
• in situ
• ex situ
In situ Bioremediation Techniques(involves direct treatment at the contaminated site)
BioventingBiospargingPhytoremediationMonitored Natural AttenuationEnhanced BioremediationPermeable Reactive Barriers
A – primary source of contaminationB – pump-and-treat of contaminants from groundwater C - bioreactor, production of biopreparation (inoculum)D - filtration unitE - aplication of a biopreparationF – imbibitional bore (drill-hole)
Ex situ Bioremediation Techniques (after-excavation treatment of the contaminated material
On site and Off site)
CompostingLandfarmingBiopilesBioreactors(slurry phase treatment)Constructed Wetlands A – decontamination area – isolated to prevent
leaching of contaminats B – system of aeration
C – leaching watersD – bioreactor – production of inoculum
E – aplication of inoculum
Air Emissions
Mixing andOxygen Transfer
LeachateControlSystem
Leachate
Air EmissionsControl Systemor Rain Shed
ContaminatedSoil
The Slovakia Project Delayed (has been frozen)Missing Act on Environmental Loads in Slovakia Waste management legislation
SolutionsContinuing in the effort to start Non-Com ProjectAccelerated acceptance of the Act on „Environmentalburdens (loads)“ in accordance with „Principle Polluter Pay“
Non-Com project
POPs Problems in Slovakia
6. Conclusions
• The market offers a number of alternative waste treatment options many of which are ready for application to PCB and obsolete pesticide stockpiles destruction
• The non-combustion approach is more environmentally safe and friendly than incinerators
• More education and promotion are needed to render these technologies competitive with the combustion technologies
Biodegradation
POPs
Bioremediation
Determination of Ecotoxicityand Genotoxicity
Isolation and identification of bacterial PCB–degraders
Bioremediation of sedimentsby autochthonous and
allochthonous bacterial strains and consortiums
Laboratorium of Environmental Biotechnology FCHFT STU
Monitoring of PCB -contaminated areas
cotton wool stopper
glass column
sorbent SILIPOR C18glass frit
Erlenmeyer flask
mediumPCBsmicroorganisms
•Apparatus for monitoring evaporationand biodegradation of PCBs.
•Sorbent SILIPOR – a chemical trap for evaporated PCB congeners.
•The fate of PCB congener: monitored as evaporated amount captured on the sorbent and the amount remaining in the medium and biomass
EvaporationEvaporation and and biodegradationbiodegradation
kev
kd
↑
→
A scheme of the processes determining the fate of PCBs in the bacterial cell suspension.
Distribution of PCBsDistribution of PCBs
State ofPCBmolecules
Evaporated& capturedon sorbent
Free &boundin medium
Partitionedin biomass Degraded
Kineticscheme
Surface area
Amount
PCBfree
PCBbound
A S
ms ma=maf+mab mb md
κev
κi
κo
κd
Kb
BiosorptionEvaporationBiodegradation
2008
2009
NATO Science Series IV: Earth and
Environmental Sciences – Vol. 19.
Springer, The Netherlands, 2006.
2006
AcknowledgementIng. Anton Kočan, PhD., SZUIng. Pavel Hucko, PhD., VÚVHPhDr. Martin Murín, EkotoxPhDr. Alena Pilváňová, Ekotox Bratislava, Slovakia
Thank you for your attention!