Environmental Safety Assessment of Chemicals in the Marine Environment:

Challenges & Opportunities.

Prof. Tom Hutchinson, University of Plymouth, UK

(tom.hutchinson@plymouth.ac.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

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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

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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

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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

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MOA4d - Transporter protein

Fluoxetine Omeprazole

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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

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• 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.

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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 tom.hutchinson@plymouth.ac.uk

Thank you for listening …

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