Introduction: What are phthalates?
Phthalates
are widely used as plasticisers
in a range of polymers
(e.g., PVC)
that are found in a wide range of consumer
products including floor- and wall covering,
furnishing, toys, car interior, clothing,
hoses etc. Phthalates are also applied
to paints and lacquers, adhesives and
sealants,
printing inks etc.
The phthalates are not chemically bound
in the polymers. Therefore, migration
or emission of the phthalates from the
product to water, air or other media in
contact with the product is likely to
occur. The emission of phthalates occurs
in all life stages of a product (from
production to disposal) and the phthalates
are thereby widespread in the environment.
Five of the most widely used phthalates
are di-(2-ethylhexyl) phthalate (DEHP),
dibutyl phthalate (DBP),
di-isononyl phthalate (DINP),
di-isodecyl phthalate (DIDP)
and benzyl butyl phthalate (BBP).
These are the phthalates in focus in the
present report.
Within the EU, specific programs on risk
assessment for new and existing chemical
substances, including the above-mentioned
phthalates, are ongoing. A directive (EEC
1993a) provides the regulation on risk
assessment of new notified chemical substances
1 and two Council regulations (EEC 1993b,
EEC 1994) on risk assessment of existing
substances.
The risk assessment process,
in relation to both human health and the
environment, entails a sequence of actions:
1) Effect assessment comprising a) hazard
identification (identification of the
adverse effects which a substance has,
and b) dose (concentration) - response
(effects) assessment (estimation of the
relationship between dose, or level of
exposure to a substance, and the incidence
and severity of an effect.
2) Exposure assessment (estimation of
the concentrations/doses to which human
populations or environmental compartments
are exposed).
3) Risk characterisation (estimation of
the incidence and severity of the adverse
effects likely to occur in a human population
or environmental compartment due to actual
or predicted exposure).
A Risk Assessment Report (EU-RAR) is prepared
for each prioritised substance. The EU-RAR
for DBP was published 18 March 2003 (http//www.ecb.jrc.it);
however the final draft for decision on
the conclusions by the EU Competent Authorities
(DBP 2001) has been used in the present
report. Regarding DEHP,
DINP
and DIDP,
the EU-RARs have not yet been published
and the final drafts for decision on the
conclusions by the EU Competent Authorities
have been used in the present report (DEHP,
2001; DINP, 2001, DIDP, 2001). For BBP,
discussions are still ongoing in the EU
Working Group and the draft report is
not yet public available.
The exposure assessment and risk characterisation
are carried out separately for three subgroups
of the human population: workers, consumers,
and man exposed indirectly via the environment.
Indirect exposure of humans
via the environment may occur by consumption
of food (fish, crops, meat and milk) and
drinking water, inhalation of ambient
air, and ingestion of soil. For existing
substance, measured levels in various
environmental compartments may be available;
however , for new substances, usually
no relevant measured data are available
and concentrations of a substance in the
environment must be estimated. The indirect
exposure is estimated by the use of the
European Union System for the Evaluation
of Substances (EUSES) - a computer modeling
program. EUSES estimates concentrations
in food and the total daily intake of
a substance based on predicted environmental
concentrations for (surface) water, groundwater,
soil, sediment and ambient air. The indirect
exposure is principally assessed on two
spatial scales: locally near a point source
of the substance, and regionally using
averaged concentrations over a larger
area. It should be noted that a third
spatial scale, the continental scale,
is also assessed by EUSES; however, this
it not included in the estimations of
the indirect exposure. EUSES can specifically
be used in the initial (or screening)
and intermediate (or refined) stages of
assessment. On the basis of the screening,
it can be decided if more data need to
be generated and if a more refined assessment
is necessary. EUSES can also be applied
for refined assessments by allowing the
replacement of default values, estimated
parameter values, or intermediate results
by more accurately estimated values or
by measured data. EUSES is not specifically
designed for site-specific assessments
(defaults represent a standard region
in EU), but adjustment of parameters may
allow for insight into specific local
or regional situations.
The consumer, i.e. a member of the general
public who may be of any age, either sex,
and in any stage of health may be exposed
to a new or existing substance by using
consumer products. A consumer product
is one, which can be purchased from retail
outlets by members of the general public
and may be the substance itself, or a
preparation, or an article containing
the substance. To assess the exposure
to substances present in consumer products,
information is needed on two sets of parameters:
1) contact parameters (where, how long
and how often contact with the consumer
occurs) and 2) concentration parameters
(the concentration of as substance in
a medium that might contact the body.
Measured data on external exposure for
specific scenarios may be available for
a number of substances; however, most
often such data are not available. A number
of computerised models have been developed;
no particular model is recommended above
any other. Whenever possible measured
or estimated values should be used for
each of the numerical parameters in a
given model, but when this is not possible
default values may be derived from available
data sources. Within the EU available
consumer products are more or less the
same and the consumer exposure assessments
in the EU-RARs are likely also to represent
more site-specific assessments and thus,
are representative for Danish consumers
as well.
Source
& © : The
Danish Veterinary and Food Administration
 "Human
exposure to selected phthalates in Denmark",
Introduction (p.11-12)
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