5. What health effects can DIDP and DINP cause in laboratory animals?
If DIDP or
DINP are swallowed, about
50% of it is absorbed from
the gut into the blood.
Absorption through the skin
is very low in rats (about 4%) and even lower in humans. About
75% of DIDP or DINP inhaled
as aerosols are absorbed.
DIDP and DINP are rapidly eliminated and do not accumulate in
tissues. DIDP and DINP
themselves are not found in the urine but their breakdown
products (metabolites) are excreted in urine. In faeces, both
DIDP and DINP as well as their major breakdown product can be
detected. A study on female rats suggests that swallowed DIDP
may possibly transfer into mother's milk.
A single dose of DIDP or
DINP which is breathed in,
swallowed (for example as a contaminant in food) or
absorbed through the skin has
a low toxicity. DIDP and
DINP are not irritant to skin, eyes or
respiratory system, nor do
they cause skin or respiratory
In rodents and dogs,
toxicity to the liver is the
main result of repeated oral exposure to
DINP. No liver changes are
observed at exposures of up to 60 mg/kg body weight/day in rats
or 15 mg/kg body weight/day in dogs for DIDP. For DINP, no
effects were observed at up to 88 mg/kg body weight/day. Effects
on the kidney are only seen at higher exposures.
DINP have not been shown to
cause damage to the inherited
genetic material in cells
(chromosomes and DNA) as shown by several laboratory
DIDP was found to cause
liver cancer through a
mechanism that is specific to rodents and does not affect
humans. It also causes a certain type of leukaemia in rats which
never occurs in humans. Similarly it causes
tumour in the kidney of male
rats by a mechanism which does not operate in humans. Thus,
there does not seem to be a concern about cancer in humans
through those processes. DIDP has not been tested in mice or
rats to see if it causes cancer, but
in-vitro tests suggest it
may cause the same type of tumours in the liver of rodents as
No adverse effects of
DIDP on human fertility are
anticipated, based on the results of studies on rats, mice and
Exposure of pregnant rats to high doses of
DINP (1 000 mg/kg body
weight/day) caused slight malformations in the fetuses, but
there were no effects at 500 mg/kg body weight/day.
In rat reproduction studies, reduced survival of the offspring
was seen, but there were no effects at concentrations up to 33
mg DIDP/kg body weight/day or159 mg DINP/kg body weight/day.
DIDP does not affect
DINP does not have an
effect on female hormones, however in a rat reproduction study,
the development of male offspring, monitored specially for
effects controlled by male hormones, was abnormal in a small
proportion (7.7%) of the offspring.
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