Environmental Safety Assessment of Chemicals in the Marine Environment:
Challenges & Opportunities.
Prof. Tom Hutchinson, University of Plymouth, UK
UKSPILL Oil Spill Seminar, 18th October 2016
Strategic Issues Management
Who sets the agenda & leads the debate?
Effectiveness of scientific engagement
Impact on society & industry
Scientific evidence
Low
High
Low
High
International committees/ Symposia
Scientific media
NGOs & Pressure Groups
Mass media
The public
Policy and legislation
Time -3 -1 0 +1 +2 +3 -2
Strategic Issues Management
Who sets the agenda & leads the debate?
Effectiveness of scientific engagement
Impact on society & industry
Scientific evidence
Low
High
Low
High
International committees/ Symposia
Scientific media
NGOs & Pressure Groups
Mass media
The public
Policy and legislation
Time -3 -1 0 +1 +2 +3 -2
Key Challenges for Chemical Assessment: • Need to replace & reduce animal testing • Increased sensitivity of analytical chemistry • Increased power of integrated biology
Growing pressure to replace, reduce or refine fish testing in environmental safety assessment
Challenge 1 Animal Testing
4
5
Approaches to Marine Testing
Mollusc larvae
Fish larvae
Crustaceans Mussels Echinoderms
Acute invertebrate tests (24 – 48 h)
Acute fish tests (96 h)
Diatoms (e.g. Skeletonema sp.)
Acute microalgal tests (72h)
The Animal Testing Challenge … • Increasing demand for (eco) toxicity data …
1
10
100
1000
10000
100000
Chemical class
Pesticideactives
HighproductionvolumeMediumproductionvolumeTSCA list
Dev tox Immuno
tox Neuro tox Repro tox Ecotox
• Ethics & costs of animal testing – millions $$$ Refs: UK Home Office (2012) report HC345 & Toxcast http://www.epa.gov/comptox/toxcast
UK scientific procedures using rodents & fish 1995-2011
Fish
Increasing sensitivity of analytical chemistry used in environmental safety assessment
Challenge 2 Analytical Chemistry
7
Chemical Contaminants Analysts Can Find Anything, Anywhere If They
Take a Large Enough Sample and Look Hard Enough
Decade Detection Limit Ratio Description
1900s 0.1% 1 in 103
Parts per thousand
1930s 1 milligramme / litre 1 in 106
Parts per million
1960s 1 microgramme / litre 1 in 109
Parts per billion
1980s 1 nanogramme / litre 1 in 1012
Parts per trillion
1990s 1 picogramme / litre 1 in 1015
Parts per quadrillion
2000s 1 femtogramme / litre 1 in 1018
Parts per quintillion
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Environmental Chemistry Trends
Timelag between the discovery and routine monitoring of chemicals
(European Science Foundation (2011) Marine Pollution). 9
Increasing power of biological measurements in field and laboratory studies
Challenge 3 Making Sense of Molecular Toxicology
10
Animal Physiology & Molecular Biology (DNA RNA Protein Function)
Reference: Campbell Biology” 9th edition (editors Reece et al., 2011) 11
Oyster eggs & sperm
Fish blood cells
The Central Dogma
• With thanks: Tim Williams, University of Birmingham
12
Genome Transcriptome Proteome
DNA mRNA Proteins
Transcription Translation Differential Splicing
RNA stability
Post Translational
Modification
Metabolites
Metabolome
Genomics Transcriptomics Proteomics Metabolomics
3 billion bases
(H sapiens)
Enzyme
Activity
20-50,000
genes
>100,000
proteins
Functional Genomics
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Predictive Ecotoxicology
Absorption
Distribution
Metabolism
Target sites
Excretion
Species selection
Field monitoring Lab studies
b) guidance on design of in vivo
tests
a) physico-chemical
properties & mammalian
MOA information
Population impacts
Environmental Risk Assessment c) safety
assessment
Chemical exposure
Economics, ethics & environmental safety assessment
Opportunities
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Toxicity Testing in the 21st Century
Ref: National Research Council (2007) Toxicity Testing in the 21st Century
• Landmark NRC (2007) report focused on human health but also relevant to ecological risks
• Less reliance on whole animal testing
• Increased integration & use of mechanistic data
• Predictive, rather than empirical
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OECD Adverse Outcome Pathways (AOP) Approach
Ref: OECD (2012) http://www.oecd.org/chemicalsafety/testingofchemicals/49963554.pdf
1. Toxicant description
2. Macromolecular target site
3. Cellular response
4. Organ response
5. Organism response
6. Population response
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OECD Definition
• Adverse Outcome Pathway: “An Adverse Outcome Pathway (AOP) is a conceptual framework that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome, at a level of biological organization relevant to risk assessment.” Ankley et al. (2010) Environ Tox Chem 29: 730-741
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OECD Grouping of Chemicals: Adverse Outcome Pathways (AOPs)
Adapted from OECD 8th VMG Ecotoxicology meeting, Paris, November 2011
Chemical 1 Chemical 2 Chemical 3 Chemical 4
Endpoint 1 Endpoint 2 Endpoint 3 Endpoint 4 Endpoint 5
Reliable data point Missing data point
Read across
Validated QSAR model
Interpolation
Extrapolation
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Modes-of-action in ecotoxicology
Refs: Verhaar et al. (1992) Chemosphere 25: 471-491; ECETOC (2007) Technical report 102, 145 pp
Verhaar et al (1992) ECETOC (2007) Chemical examples
1 MOA1 - Narcotics - Linear alkyl benzene sulphonate
2 MOA2 - Polar narcotic chemicals
- Phenol
3 MOA3 - Reactive chemicals - Epichlorohydrin
4 MOA4 - Specifically acting MOA4a – Enzyme Chlorpyrifos Fadrozole
MOA4b - Ion channel blocker
Cypermethrin 5
MOA4c – Receptor Atenolol Ethinylestradiol
6
MOA4d - Transporter protein
Fluoxetine Omeprazole
7
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Mode of Toxic Action: Key Protein Targets
(eg beta blockers, ethinylestradiol) (eg aspirin, fadrozole)
(eg brevetoxin, cypermethrin)
(eg tricyclic antidepressants)
Ref: Rang et al (2003) & ECETOC (2007) 20
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Drug Target Conservation: Bioinformatics Approach
Ref: Gunnarsson et al. (2008) Env Sci Technol 42: 5807-5813
Medical endocrine disrupters
Cholesterol
Testosterone
Dihydrotestosterone
Estrogen
Receptor
(ER)
Oestradiol
• side-chain cleavage
• 17b-hydroxy dehydrogenase
• C17C20 lyase
• 17a-hydroxylase
5a reductase
Androgen
Receptor
(AR)
Aromatase
Ref: Purchase & Randall (1998) Pure Appl Chem 70: 1671-1784
Tamoxifen
Fulvestrant
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Environmental endocrine disrupters
Cholesterol
Testosterone
Dihydrotestosterone
ER
Oestradiol
• side-chain cleavage
• 17b-hydroxy dehydrogenase
• C17C20 lyase
• 17a-hydroxylase
5a reductase
AR
Ketoconazole
Finasteride
Competitive Agonists Competitive Agonists
Tributyltin
Aromatase
Bisphenol A
Diethylstilbestrol
Ethinylestradiol
Genistein
Nonylphenol
DDT & metabolites
Procymidone
Vinclozolin
Tamoxifen
Flutamide
RXR
23
• Problem of ‘base set’ of algae, crustacean & fish testing: 82% marine species not represented (18 phyla marine only)
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Marine Biodiversity >> Freshwater
Source: ECETOC (2001) Technical Report number 82
SETAC Seville: Marine Risk Assessment Short Course
Evolution of physiological systems .. knowledge from genomics
Protostomes
Molluscs
Deuterostomes
Chordates Echinoderms
Annelids
Crustaceans Insects
Cnidarians
Protozoans
Vertebrate-type steroids
Ecdysteroids, terpenoids
& neuropeptides 25
Organizing the AOP knowledge – the Effectopedia way.
26
Integrated Approach
Hutchinson et al. (2013) Mar Poll Bull 74: 517-525 27
Conclusions Effectiveness of scientific engagement
Impact on society & industry
Scientific evidence
Low
High
Low
High
International committees/ Symposia
Scientific media
NGOs & Pressure Groups
Mass media
The public
Policy and legislation
Time -3 -1 0 +1 +2 +3 -2
Strategic Opportunities for Safety Assessment: • AOPs to replace & reduce animal testing • Focus the application of analytical chemistry
for environmentally realistic testing • Utilise the predictive power of modern
biology
Contact details: Prof Tom Hutchinson, University of Plymouth, Drake Circus, Plymouth PL4 8AA Tel 07939 673129 or email [email protected]
Thank you for listening …
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