mechanistic effect models for environmental risk assessment Tjalling Jager SETAC Nantes April 2016 Contents Role of models in ERA Issues in selecting useful effects models Take home messages ID: 549183
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Slide1
Selecting mechanistic effect models for environmental risk assessment
Tjalling Jager
SETAC Nantes, April 2016Slide2
ContentsRole of models in ERAIssues in selecting useful effects models
Take home messages
exposure assessment
risk
effects assessmentSlide3
concentrations
,
time and spaceExposure assessment
mechanistic
fate modeltheoryenvironment
phys-chem propertiesrelease scenarioSlide4
Effects assessment
statistics
‘safe’
concentration
toxicity testarbitrary factorsStandardised:
exposure timetest conditionsspecies/endpointconstant exposureSlide5
Risk assessment?
mechanistic
fate
model
statistics &safety factorsSlide6
predicted
‘impacts’ over time (and
space)
mechanisticfate model
New paradigm for ERAmodel parametersmechanisticeffect model(s)environment
model parameterssee Jager (in press)dedicatedtestingrelease scenarioSlide7
Which effects model(s)?Huge range of models available …
(e.g., Galic
et al, 2010, Schmolke et al, 2010)Models differ in:level of organisation
complexitygenerality‘quality’ (e.g., GMP)underlying assumptions…Don’t look at models in isolation!Slide8
Models in their context
p
rotection goals
effect models
test protocols
defined by regulators,
too vague …
developed by modellers,
not tailored to ERA …
developed by experimenters,
not tailored to model needs …
options
constraintsSlide9
Daphnia magna and dichloroaniline
individual
population
ecosystem
TKTD modelse.g., IBMse.g., AQUATOXintrinsic rate
p
rotection goals
effect models
test protocols
options
constraintsSlide10
DEBtox (e.g., Jager & Zimmer, 2012)
individual
populationecosystem
TKTD models
e.g., IBMse.g., AQUATOXintrinsic rateSlide11
DEBtox, MoA: direct effect on reproNEC = 6.4 µg/L (5.6-7.0)
0
5
10
15
20
time (days)
0
20
40
60
80
100
120
140
Conc. 0 µg/L
Conc. 2.5
µg/L
Conc. 5
µg/L
Conc. 10
µg/L
Conc. 20
µg/L
Conc. 40
µg/L
cumulative offspring
individual
population
ecosystem
TKTD models
e.g., IBMs
e.g., AQUATOX
intrinsic rate
Data from
Klüttgen
&
Ratte
(1994)
p
rotection goals
test protocolsSlide12
p
rotection goals
Exponential growth under constant conditions
0
5
10
15
20
25
30
35
40
c
oncentration DCA (µg/L)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
intrinsic rate (d
-1
)
individual
population
ecosystem
TKTD models
e.g., IBMs
e.g., AQUATOX
intrinsic rate
food 100%
food 90%
food 80%
test protocolsSlide13
Martin et al
(2013), DEB combined with IBM
individual
population
ecosystemTKTD modelse.g., IBMse.g., AQUATOXintrinsic rateData from Sokull-Klüttgen (1998)Slide14
Population predictions (DEB-IBM)lab conditions, semi-batch feeding
Data from Preuss et al (2010)
time (d)
time (d)
abundancecontrol40 µg/Lindividual
populationecosystemTKTD modelse.g., IBMse.g., AQUATOXintrinsic rate
p
rotection goals
test protocolsSlide15
Semi-batch fed Daphnia in
isolation …
nutrients
individual
populationecosystemTKTD models
e.g., IBMse.g., AQUATOXintrinsic rate
p
rotection goals
test protocolsSlide16
Semi-batch fed Daphnia in isolation …Add
parasites, disease, migration, spatial aspects …
nutrients
individual
population
ecosystemTKTD modelse.g., IBMse.g., AQUATOXintrinsic rate
p
rotection goals
test protocolsSlide17
Summarising
individual
population
ecosystem
TKTD modelse.g., IBMse.g., AQUATOXintrinsic rate
ecological realism, specificity, complexity …Slide18
individual
population
ecosystem
TKTD models
e.g., IBMs
e.g., AQUATOX
intrinsic ratetoxicity testingSummarising
data needs, potential model integration …
ecological dataSlide19
individual
population
ecosystem
TKTD models
e.g., IBMs
e.g., AQUATOXintrinsic rate
toxicity testingtesting recoverySummarising
ecological data
landscape and mobility
options for recovery…
intrinsic rateSlide20
Take home 1Science-based ERA requires effect models
Preferably in all tiers (just like fate models)Set of standard models or sub-models e.g., Hommen
et al, 2015; Grimm & Berger, 2016Slide21
Take home 2Model selection cannot be viewed in isolation
Closely tied to protection goals and test protocolswhat exactly do we want to protect
?adjust test protocols to match model needsModel ‘quality’ and ‘realism’ is not all …link to protection goalwell-established principlestransparency…Slide22
Take home 3ERA needs more ambitious road map for the future
More structured dialogue between stakeholders …Ecotoxicology needs focus on theory and modelling
In science and education …Slide23
More information:on DEBtox/GUTS:
www.debtox.info
summercourse dynamic modelling of toxic effects, 9-17 August 2016 (DK) (register before 1 June
!)Relevant new project:
“Critical evaluation of effect models for risk assessment of plant protection products”(UBA, UFOPLAN 3715674080)