1. Which information identifies a chemical as endocrine disrupting?
Poul Bjerregaard
Institute of Biology
University of Southern Denmark
Odense
and
Danish Centre on Endocrine Disrupters
UNEP EDC Advisory Group meeting, Geneva , September 25-26, 2015

2. WHO EDC definition Endocrine mechanism Adversity
Plausible link between the two

3. Adversity according to WHO/IPCS 2004
A change in morphology, physiology, growth, reproduction, development or lifespan of an organism which results in impairment of functional capacity or
impairment of capacity to compensate for additional stress or increased susceptibility to the harmful effects of other environmental influences

4. Adversity? Risk assessment of chemicals What do we want to protect?
Human risk assessment:
Every individual
Environmental risk assessment:
The structure and function of the ecosystem

5. Environmental risk assessment
Protection of ecosystem structure and function
The aim is to protect 95% of the species
‘Adversity ’defined from population effects
Not effects on the individual

6. Environmental risk assessment
Protection of ecosystem structure and function
The aim is to protect 95% of the species
‘Adversity’ defined from population effects
Not effects on the individual

7. Relevant OECD test guidelines
Human risk assessment
TG 416 or 433 (mammals)
E.g. malformed male genitals, altered AGD
Environmental risk assessment
TG 234
Fish Sexual Development Test

8. Fish Sexual Development Test
Altered content of yolk proteins
Controlled by oestrogen
Indicates endocrine mechanism - not adversity
Altered sex ratio
Indicates endocrine mechanism and adversity
OECD Guidance Document 150

9. Danish suggestion for EDC-criteria
Category 1 – Endocrine Disrupter
Adverse in vivo effects
ED mode of action in vivo clearly linked to adverse in vivo effects
Category 2a – Suspected Endocrine Disrupter
Adverse effects in vivo where an ED MoA is suspected
ED MoA in vitro combined with toxicokinetic in vivo data
ED MoA in vivo suspected to be linked to adverse effects in vivo
Category 2b – Indicated Endocrine Disrupter
in vitro/in silico evidence indicating potential for ED in vivo

10. Exemplified by chemical UV filters
Category 2a
Category 1
Danish 2012-assessment
BP-3:
Indications of oestrogenic
and anti-androgenic effects.
Not consistent
Category 2a
Category 2a
TG234 needed

11. Sexual development in zebrafish♀ ♂
Hatch
20 days
40 days
60 days

12. Sex ratio altered – more ♀
Kinnberg et al Environ.Toxicol.Chem. In press.

13. No consistent effect on yolk proteins
12 d exposure

14. Conclusion Exposure to benzophenone 3 skews sex ratioso
Benzophenone 3 is an EDC

15. Is BP-3 oestrogenic or anti-androgenic?
Does it matter ?
Depends on the requirement for detailed knowledge about the mechanism of action
Detailed knowledge about ‘Adverse Outcome Pathways’ is desirable
But not always obtainable

16. A chemical may have multiple AOPs
Prochloraz
Fungicide

17. Prochloraz: More male zebrafish*
100
Female
Male
Intersex
Undifferentiated 80 60 % 40 20 73 72 72 69
Control 16 m
g/l 64 m
g/l
202 m
g/l
Prochloraz
Prochloraz
Prochloraz
Kinnberg et al Comp. Biochem. Physiol.145C,

18. Prochloraz is anti-androgenic in rats
Laier et al Toxicol.Appl.Pharmacol. 213,

19. Effect of prochloraz Cholesterol Prochloraz Anti-androgenic in rats
Testosterone
Prochloraz
Inhibits aromatase
in zebrafish (?)
Oestrogen

20. Conclusion
Detailed knowledge on ‘Adverse Outcome Pathways’ is not necessarily needed to reach conclusions on endocrine disrupting activity