Transcript Science relating to Nanotechology, Endocrine Disrupters

Endocrine Disrupters
Lovells LLP
Industries which may be affected by
endocrine disrupters
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Chemicals
Plastics
Agrochemicals
Water companies
Farming
Food
Cosmetics
Endocrine system
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Hypothalamus
Pituitary
Thyroid
Pancreas
Adrenal glands
Ovaries
Testes
Hormone action and receptor binding
Receptor
Hormone
Target Cell
http://www.emcom.ca/primer/hormones.shtml
Hormone feedback pathways and
homeostasis
http://www.who.int/ipcs/publications/en/ch3.pdf
Example - control of spermatogenesis and
testosterone secretion
Definition of endocrine disrupter
• An endocrine disruptor is an exogenous substance or
mixture that alters function(s) of the endocrine system
and consequently causes adverse health effects in an
intact organism, or its progeny, or (sub)populations.
• A potential endocrine disruptor is an exogenous
substance or mixture that possesses properties that
might be expected to lead to endocrine disruption in an
intact organism, or its progeny, or (sub)populations.
[http://www.who.int/ipcs/publications/en/ch1.pdf]
Sites of endocrine disruption
Hormone synthesis
Hormone
metabolism and
excretion
Hormone
transport
Receptor
Hormone binding
Hormone
Target
Cell
Mechanism of endocrine disruption
• EDCs can bind to a receptor and trigger the usual
response.
• EDCs can bind to the receptor and not trigger a
response but cause a blockage such that the appropriate
hormone cannot bind
• Can interfere with the production, transportation,
metabolism and excretion of hormones
• Many EDCs are capable of multiple, sometimes
opposing, actions in different tissues
Effects of endocrine disruption - TBT
http://www.medinavalleycentre.org.uk/im
ages/fs_marine_biology_dogwhelk.jpg
•http://www.credocluster.info/images/imposex.gif
TBT
• Survey of the dogwhelk showed a high degree of
imposex
• Observed to be in areas close to shipping activity
• Tissues of the dogwhelk were analysed for several
compounds and showed high levels of tin
• Experiments conducted using TBT which demonstrated
a causative link
• Mechanism by which the disruption is caused is still
unclear
Effects of endocrine disruption - DES
• Synthetic estrogen
• Given to pregnant women
who were at risk of
miscarriage or premature
birth (1938-1971)
DES
http://www.cdc.gov/des/
Examples of established endocrine
disrupters
• Dioxins
• PCBs
• DDT
Examples of chemicals which are potential
endocrine disrupters in humans
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TBT
Bisphenol A
Atrazine
Phthalates
Phytoestrogens
Alkylphenols
Brominated flame retardants
Products which contain potential endocrine
disruptiers
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Industrial chemicals
Pesticides
Herbicides
Plastics (phthalates)
Cosmetics (bisphenol A)
Sunscreens (4MBC & OMC)
Fire retardants (brominated compounds)
Problems associated with the management
of endocrine disrupters
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Identification of potential disrupters
Multigenerational effects
Timing of exposure
Combined exposures
Multiple effects on different endocrine pathways
Persistence and cumulative effects
Appropriate and standardised tests for ED ability
Low dose effects/threshold
Dose-response
Attempts to identify ED chemicals
• EC
– Priority list of substances for further evaluation of their role in
endocrine disruption
– CREDO research initiative
– REACH
• EPA’s Endocrine Disruptor Screening Program (EDSP)
– “Draft List of Chemicals for Initial Screening” June 2007
– Endocrine Disruptors Research Initiative
• WHO
– 2002 Global Assessment of the State of the Science of
Endocrine Disruptors
EMF
Lovells LLP
EMF spectrum
Frequency/wavelength affects
properties of EM waves
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Very high frequency radiation
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Radiofrequency wavelengths (10MHz to 300GHz)
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Lots of energy
Ionising radiation
Able to easily penetrate (and damage) biological material
X-rays and gamma rays
Less energy associated
Non-ionising radiation
Less able to penetrate biological materials
Mobile phones and microwave
Low- and extra-low frequency radiation
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Low power levels
Non-ionising
Power lines
Risks of EMF
• Ionising radiation – various adverse effects including cancer
• Ultraviolet and visible radiation – various adverse effects including
skin cancer
• Radiofrequency radiation – exposure at greater than ICNIRP
guideline levels can lead to thermal effects
• Low frequency radiation – exposure greater than ICNIRP guideline
levels can lead to shocks and effects on the nervous system
• Magnetic fields – classified by IARC as possibly a human
carcinogen on the basis of studies relating to childhood leukemia
How are electric and magnetic fields
generated
Mobile phones
http://www.hpa.org.uk/radiation/understand/information_sheets/mobi
le_telephony/background_info.htm
Guidelines for exposure to non-ionising
radiation set by ICNIRP
European power frequency
Frequency
Mobile phone base station
frequency
Microwave
oven
frequency
50 Hz
50 Hz
900 MHz
1.8 GHz
2.45 GHz
Electric field
(V/m)
Magnetic
field (µT)
Power
density
(W/m2)
Power
density
(W/m2)
Power
density
(W/m2)
Public
exposure
limits
5 000
100
4.5
9
10
Occupational
exposure
limits
10 000
500
22.5
45
ICNIRP, EMF guidelines, Health Physics 74, 494-522 (1998)
Examples of typical maximum exposures
Source
Typical maximum public exposure
Electric field (V/m)
Magnetic flux density
(µT)
Natural fields
200
70 (Earth's magnetic
field)
Mains power
(in homes not close
to power lines)
100
0.2
Mains power
(beneath large power
lines)
10 000
20
Electric trains and
trams
300
50
TV and computer
screens
(at operator position)
10
0.7
Typical maximum public exposure (W/m2)
TV and radio
transmitters
0.1
Mobile phone base
stations
0.1
Radars
0.2
Microwave ovens
0.5
Source: WHO Regional Office for Europe
IARC classification of static electric and magnetic
and extremely low-frequency electric fields
“Evaluation
There is limited evidence in humans for the carcinogenicity of extremely low-frequency magnetic fields
in relation to childhood leukaemia.
There is inadequate evidence in humans for the carcinogenicity of extremely low-frequency magnetic
fields in relation to all other cancers.
There is inadequate evidence in humans for the carcinogenicity of static electric or magnetic fields and
extremely low-frequency electric fields.
There is inadequate evidence in experimental animals for the carcinogenicity of extremely lowfrequency magnetic fields.
No data relevant to the carcinogenicity of static electric or magnetic fields and extremely low-frequency
electric fields in experimental animals were available.
Overall evaluation
Extremely low-frequency magnetic fields are possibly carcinogenic to humans (Group 2B).
Static electric and magnetic fields and extremely low-frequency electric fields are not classifiable as to
their carcinogenicity to humans (Group 3).”
http://monographs.iarc.fr/ENG/Monographs/vol80/volume80.pdf
World Health Organisation Factsheet – June
2007 - extremely low frequency fields
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“In 2002, IARC published a monograph classifying ELF magnetic fields as
"possibly carcinogenic to humans". This classification is used to denote an
agent for which there is limited evidence of carcinogenicity in humans and
less than sufficient evidence for carcinogenicity in experimental animals
(other examples include coffee and welding fumes). This classification was
based on pooled analyses of epidemiological studies demonstrating a
consistent pattern of a two-fold increase in childhood leukaemia associated
with average exposure to residential power-frequency magnetic field
above 0.3 to 0.4 µT. The Task Group concluded that additional studies
since then do not alter the status of this classification.
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However, the epidemiological evidence is weakened by methodological
problems, such as potential selection bias. In addition, there are no
accepted biophysical mechanisms that would suggest that low-level
exposures are involved in cancer development. Thus, if there were any
effects from exposures to these low-level fields, it would have to be
through a biological mechanism that is as yet unknown. Additionally,
animal studies have been largely negative. Thus, on balance, the evidence
related to childhood leukaemia is not strong enough to be considered
causal.”
Research into potential effects of RF
radiation on humans
• World Health Organisation - The International EMF
Project
• REFLEX
• MTHR - UK Mobile Telecommunications and Health
Research Programme
• Interphone
Reports on EMF/RF
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1999 Canadian Report Royal Society of Canada's Expert Panel's review of the potential health risks of
radiofrequency fields from wireless telecommunication devices
2000 Zmirou Report French Health General Directorate
2000 Stewart Report UK Independent Expert Group
2002 Dutch Report Health Council of the Netherlands, advisory report
2003 Swedish Report Swedish Radiation Protection Authority (SSI) First annual report from SSI's Independent
Expert Group on Electromagnetic Fields
2003 AGNIR Report NRPB's Independent Advisory Group on Non-Ionising Radiation Report 'Health Effects from
Radiofrequency Electromagnetic Fields'
2004 Dutch Report Health Council of the Netherlands Electromagnetic Fields Annual Update 2003
2004 Review by ICNIRP Standing Committee on Epidemiology A comprehensive review of the epidemiology of
health effects of radiofrequency exposure
2004 Swedish Report Swedish Radiation Protection Authority (SSI) Second annual report from SSI's Independent
Expert Group on Electromagnetic Fields
2005 NRPB Report W65 A Summary of Recent reports on Mobile Phones and Health (2000-2004)
2005 NRPB Report Documents of the NRPB - Mobile Phones and Health Volume 15 No.5 2004
2005 French Agency for Environmental Health Safety Opinion on Mobile Telephony
2005 Dutch Report Health Council of the Netherlands Electromagnetic Fields Annual Update 2005
2005 Swedish Report Swedish Radiation Protection Authority (SSI) Third annual report from SSI's Independent
Expert Group on Electromagnetic Fields
2007 Dutch Report Health Council of Netherlands
2007 Swedish Report Swedish Radiation Protection Authority (SSI)
2007 June Canadian Report Update report by the Royal Society of Canada's Expert Panel on Potential Health
Risks of Radiofrequency Fields from Wireless Telecommunication Devices
World Health Organisation Factsheet – May 2006 Base stations and wireless technologies
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“Considering the very low exposure levels and research results
collected to date, there is no convincing scientific evidence that
the weak RF signals from base stations and wireless networks
cause adverse health effects.”
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“While no health effects are expected from exposure to RF fields
from base stations and wireless networks, research is still being
promoted by WHO to determine whether there are any health
consequences from the higher RF exposures from mobile phones.”
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“The International Agency for Research on Cancer (IARC), a WHO
specialized agency, is expected to conduct a review of cancer risk
from RF fields in 2006-2007 and the International EMF Project will
then undertake an overall health risk assessment for RF fields in
2007-2008.”