HM, H Drexler, and J Angerer. 2003. An estimation of the
daily intake of di(2-ethylhexyl)phthalate (DEHP) and other phthalates
in the general population. International
Journal of Hygiene and Environmental Health 206:77-83.
and his colleagues report strikingly high phthalate levels
in a sample of German men and women. They conclude that their results
"unequivocally prove that the general German population is
exposed to DEHP to a much higher extent than previously believed."
By their calculations, 31% of the subjects had values higher than
for DEHP of 20 µg/kg body weight/day of the U.S. EPA. Twelve
percent of subjects exceeded the European Union's "Tolerable
Daily Intake" level of 37 µg/kg.
to Koch et al., their findings are of great public health
importance. "We are not aware of any other environmental
contaminant for which the TDI and RfD are exceeded to such an extent
within the general population.
did they do? Koch et al. obtained urine samples
from 85 people living in the southern German city of Erlangen. None
of the subjects had been exposed occupationally to phthalates.
a new technique out of analytical chemistry called "multidimensional
liquid chromatography tandem mass spectrometry" they detemrined
the levels of a series of phthalate metabolites in the urine sample.
Based on those measurements, they then calculated an estimate of
the daily exposure to different phthalates that would have been
required to produce the levels measured in the urine. Those calculations
were based on previous studies in which people's urine levels were
monitored following ingestion of known quantitites of phthalates.
did they find? All people sampled had phthalate metabolites
in their urine, with metabolites of DEHP being highest.
estimated daily intake of DEHP clearly exceeds the "tolerable
daily intake" level established by the EU of 37 µg/kg.
In fact, 12% of the people sampled had levels higher than
DEHP's TDI. For the second highest, DnBP, roughly 50% of the
people sampled were within one-sixth of the TDI.
had slightly higher levels of DEHP compared to women. Women
had slightly higher levels of DnBP compared to men (data not
estimates based on average of the estimate calculated separately
from two metabolites of DEHP in urine.
Table adapted from Koch et al.
does it mean? If data
from the US about phthalate exposures were not already sufficient
to raise concerns, these results from Germany should put
public health authorities on notice that phthalate exposures
in the general population are likely to be much higher than realized.
Their "intake calculations demonstrate beyond doubt that an
unexpectedly high share of the general population is exposed to
DEHP and exceeds the TDI of the CSTEE
and the RfD of the EPA."
TDI and RFD concentrations are derived from data on experimental
effects on animals, specifically on an estimate of what level is
low enough so that no adverse effect can be observed in exposed
animals (the no observed adverse effect level, or NOAEL). A series
of safety factors are then used to add a margin of safety because
of uncertainties about how applicable the animal results are to
humans. The resulting TDI and RFDs then become the goals for exposure
regulation, to make sure that people's exposures do not come close
to a level at which adverse effects are likely.
fact that 30% and 12% of calculated exposures for DEHP exceed the
RFD and TDI levels, respectively, is a clear signal that
something is wrong in the way that DEHP is being used and regulated.
The data for DnBP, while indicating a larger gap between prevailing
exposures and levels of concern, also raise flags about the adequacy
of current regulations.
of exposure to DEHP are ubiquitous. Its principal use is as a plasticizer
for polyvinyl chloride, to make PVC plastic more flexible. Flexible
PVC products include "wall coverings, tablecloths, floor tiles,
furniture upholstery, shower curtains, garden hoses, swimming pool
liners, rainwear, baby pants, dolls, toys, shoes, automobile upholstery
and tops, packaging film and sheet, sheathing for wire and cable,
medical tubing, and blood storage bags. Polyvinyl chloride is also
used to produce disposable medical examination and surgical gloves,
the flexible tubing used to administer parenteral solutions, and
the tubing used in hemodialysis treatment," according to the
research is underway on the toxicological effects of phthalates,
especially DEHP, which is thought to be the most hazardous chemical
in the family. The main concern arises because of DEHP's ability
to interfere with androgens, particularly during fetal development.
Experiments with animals reveal a range of adverse effects on the
developing male fetus, especially with respect to growth of the