Download VCI Position: Discussion about limit values for endocrine disruptors

VCI Position:
Discussion about limit values for endocrine disruptors
Status:
12.12.2012

Ongoing discussion
Is it possible to determine thresholds and limit values for hormone active substances?
This question is currently being discussed in the political arena - and the answers will have
decisive impacts on the usage of chemicals.

What are endocrine active substances; what are endocrine disruptors?
Endocrine active (hormone active) substances are substances which cause a reaction of the
hormone system. Where such substances cause adverse effects, one speaks of endocrine
disruptors.
Hormones are important messenger substances within the body. Endogenous substances
are produced in glands, released into blood and transported to target organs, where they
bind to receptors and thus unfold their effect. There are many hormone-driven reactions in
the body. Processes such as e.g. metabolism, growth and development can be controlled
and regulated in this way. Beside endogenous hormones, also the following substances are
of relevance: natural substances with hormonal effect (e.g. some plant ingredients) and
hormone active chemicals.

What is a threshold?
A threshold is an intake (dose) starting from which damage is observed. No (harmful) effects
are caused below the threshold.
Generally, the dose is decisive for the effect of a substance. For this reason, dose-effect
relationships are examined in assessments of chemicals - this also applies for the
assessments of hormone active substances. This means that a substance is tested at
various concentrations and according to generally recognized methods. A threshold can be
determined in most cases.

What is a health-based limit value?
The limit value states the dose up to which a substance is safe for humans and no damage
is to be expected. Limit values are important in assessments of substances, in order to
ensure their safe handling and use.
The limit value is obtained from the theshold; it is always lower than the threshold, because
additional safety factors are applied. Here, the precautionary principle applies, with safety
factors for particularly sensitive groups of persons (e.g. children, pregnant women) being
taken into account when deriving limit values. Such safety factors also exist for the transfer
of data from animal testing to humans and the type of studies used for deriving the limit
values.

For which substances can no thresholds be derived?
No thresholds - and, consequently, no limit values - can be laid down for substances where
(theoretically) any exposure can cause damage. Examples are some carcinogenic
substances which directly damage the DNA. They have irreversible effects, and no level can
be stated up to which the substance is not harmful. A safe usage under adequate control is
therefore not possible.

Reasons why limit values can be derived for endocrine disruptors:
- THE BODY HAS MECHANISMS TO KEEP IN BALANCE. DAMAGE CAN OCCUR ONLY IF THESE
MECHANISMS ARE OVERSTRAINED : Most hormonal reactions do not cause any damage.
Normally the body remains in balance irrespective of measurable hormonal reactions, up to
a certain threshold. The threshold can be low in certain development phases, but it can be
determined with suitable methods. This enables the derivation of health-based limit values
in principle.
- MANY REACTIONS ARE REVERSIBLE SO THAT OBSERVED EFFECTS ARE OFTEN TIME-LIMITED
AND DO NOT CAUSE ANY DAMAGE : There are many hormone-driven reactions in the body
that lead to effects. We influence the hormonal regulation with e.g. consumption of caffeine.
Furthermore, forms of behavior (such as intensive sports activities) can cause hormonal
effects. These reactions however only lead to time-limited effects and do not lead to any
damage.
- MOST ENDOCRINE HARMFUL CHEMICALS HAVE MUCH LOWER EFFECTS THAN NATURAL
HORMONES : The effect of a hormone active substance depends, inter alia, on how strongly
it binds to the respective hormone receptor. Hormones unfold their effects according to the
"lock-and-key principle", i.e. further reactions happen only if the hormone ("key") fits in the
"lock" (receptor). Many hormone active chemicals bind only weak, because they do not fit
well into the "receptor lock".
THE VCI's POSITIONS AND DEMANDS
1. Derive health-based limit values for endocrine disruptors
The dose is decisive for the effect of a substance, and this applies also to endocrine
disruptors. For this reason, limit values can be derived for these substances too. Here,
special attention needs to be given to particularly sensitive groups of the population (e.g.
children or pregnant women) in the form of safety factors.
There is no evidence of endocrine disruptors having to be assessed as "substances
without threshold concentration" generally.
2. Consider risk assessments in regulation
The safe handling and use of hormone active substances is possible. In the light of
existing findings, a limit value can be derived on the basis of sound risk assessment.
Further research is needed in some fields for a better understanding of the effects of
endocrine disruptors. The chemical industry is actively involved in research activities, with
the goal of developing safe products.
3. Take into account the state of science
Endocrine disruptors and their effects can be assessed on a scientific basis. This includes
the deriving of limit values. From the VCI's viewpoint, there is no scientifically justified
concern substantiating the contrary.