Importance of exposure dynamics in Importance of exposure dynamics in aquatic ecosystem risk assessmentaquatic ecosystem risk assessmentMelissa Morselli1, Matteo Semplice2, Antonella Zichella1

and Antonio Di Guardo1 *

1 Department of Science and High Technology, University of Insubria, Via Valleggio 11, 22100 Como, Italy2 Department of Mathematics, University of Turin, Via Carlo Alberto 10, 10123 Torino, Italy

* E-mail: antonio.diguardo@uninsubria.it

FrameworkFrameworkEEnvironmental RRisk AAssessment

- Environmental realismEnvironmental realism- Ecological relevanceEcological relevance- Methodological accuracyMethodological accuracy

of current approaches… “Addressing the New Challenges for Risk Assessment” (EC Scientific Committees)

... ongoing discussion...

?!

E.g., exposure assessment by means of steadysteady--state modelsstate models

CEFIC-LRI project“ChimERA: An integrated modelling tool for ecological risk “ChimERA: An integrated modelling tool for ecological risk

assessment”assessment”

ObjectivesObjectives

- Compartments and subCompartments and sub--compartmentscompartments: water and sediment + dissolved organic carbon (DOC), detritus, phytoplankton, and macrophytes- DynamicsDynamics of emissions, environmental parameters (e.g., temperature), macrophytes, phytoplankton and detritus mass and lipid content and DOC- Spatial discretizationSpatial discretization: different sub-environments in water and sediment

Fate and exposure subFate and exposure sub--modelmodel

Side view

Top view

WATER

SEDIMENT

* Di Guardo, A., Ferrari, F., Infantino, A. (2006) Environ Sci & Pollut Res 13(1), 50-58

- Dynamic surface water fugacityfugacity model- Water (water + suspended solids) and sediment (pore water + sediment solids)- Hourly concentrations and chemical fluxes between compartments- DynamicDynamic in terms of emission and environmental parameters

Starting point: DynA Model *Starting point: DynA Model *Chemical emission

Contaminatedsediment

11stst result: subresult: sub--model unitmodel unit

- CompartmentsCompartments: water, sediment, macrophytes *, phytoplankton **, total suspended particles (TSP), dissolved organic matter (DOM)- Layered sedimentLayered sediment- OutputOutput: hourly chemical concentrations in all compartments + chemical fluxes

Chemical emission

TSP DOM

Contaminatedsediment

* Armitage, J.M., Franco, A., Gomez, S., Cousins, I.T. (2008) Environ Sci & Pollut Res 13(1), 50-58** Del Vento, S., Dachs, J. (2002) Environ Toxicol Chem 21(10), 2099-2107

22ndnd result: spatial discretizationresult: spatial discretization

- Multiple unit connection unit connection through water flowwater flow (hydrological module)- SaintSaint--VenantVenant equationequation for rectangular-section channel with variable width and depth *- Friction accounted for using the Manning’s equation **- OutputOutput: hourly water volumes (m3) + input and output fluxes for each unit (m3 h-1)- From water fluxes: phytoplankton, TSP and DOM fluxes (m3 h-1)

* Balbas, J., Karni, S. (2009) ESAIM: M2AN 43, 333-351** Gordon, N.D., McMahon, T.A., Finlayson, B.N., Gippel, C.J., Nathan, R.J. (2004) Wiley

Side viewSingle unit

Sensitivity analysisSensitivity analysis- Simplified system (single sediment layer, 5-cm deep), two chemicals- Tested parametersTested parameters: emission, physical-chemical properties, MTCs, temperature, compartment volumes and organic carbon fractions- TargetsTargets: water-dissolved and sediment pore-water concentrations

Most influential parametersMost influential parameters

EmissionOC fraction of primary producers, TSP and DOM

Uptake/release rate constants for primary producers, TSP and DOMTemperature

- 30 - 20 - 10 0 10 20 30x direction (m)

05

10

- 5- 10

y dire

ction

(m)

Illustrative application: scenario (1)Illustrative application: scenario (1)

17001320

HL wat (h)

550005.180.00060.132B48002.53.9E-0533A

HL sed (h)log KOWVP (Pa)WS (mg/L)Chemical

Top view

Water flow

Chemical discharge

Side view

Illustrative application: scenario (2)Illustrative application: scenario (2)

Month0

20406080

J F M A M J J A S O N D

Conc

. (mg/L

)PhytoPhyto TSPTSP

DOCDOC

05

1015202530

J F M A M J J A S O N DMonth

T (°C)

Water temperatureWater temperature0.00E+004.00E-088.00E-081.20E-071.60E-07

J F M A M J J A S O N DMonth

Emiss

ion (m

ol/h)

EmissionEmission

Illustrative application: results (1)Illustrative application: results (1)

0.00E+005.00E+021.00E+031.50E+032.00E+032.50E+033.00E+03

J F M A M J J A S O N DMonth

Conc

. (ng/L

)

0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+00

J F M A M J J A S O N DMonth

Conc

. (ng/L

)Chemical BChemical BChemical AChemical A

WaterWater--dissolveddissolved

Sediment Sediment porepore--waterwater

Illustrative application: results (2)Illustrative application: results (2)

Side view

0.00E+005.00E+021.00E+031.50E+032.00E+032.50E+03

J F M A M J J A S O N DMonth

Conc

. (ng/L

)

Slice 1 Slice 1 (Emission)(Emission)

0.00E+002.00E+014.00E+016.00E+018.00E+011.00E+02

J F M A M J J A S O N DMonth

Conc

. (ng/L

)

Slice 3Slice 3Slice 4Slice 4Slice 5Slice 5

Chemical BChemical B

Illustrative application: results (3)Illustrative application: results (3)

020406080

J F M A M J J A S O N D

Conc

. (mg/L

)PhytoPhyto TSPTSP

DOCDOC

0.00E+001.00E-092.00E-093.00E-094.00E-095.00E-096.00E-097.00E-09

J F M A M J L A S O N DMonth

Flux (

mol/h

) PhytoPhytoDOMDOMTSPTSP

OutflowOutflowDegradDegrad

Slice 3Slice 3

ConclusionsConclusions

Ongoing workOngoing work-- Coupling Coupling with effect models (TK/TD-IBM sub-models)- Implementation of equations to describe phytoplankton, macrophyte and detritus dynamics

Future workFuture work

- Flexible dynamic unit model- Basis for the simulation of connected water bodies (rivers/ponds)

- SensitivitySensitivity and uncertainty analysesuncertainty analyses- CalibrationCalibration and validation validation (literature + experiments)

AcknowledgementsAcknowledgements

Thanks for your attentionThanks for your attention

You can also find me in the Exhibition Hall (poster TU193)You can also find me in the Exhibition Hall (poster TU193)

The ChimERA project is financed by the Long-range Initiative of CEFIC (www.cefic-lri.org) (project code: LRI-ECO19)