The NTP Center for the Evaluation of Risks to Human Reproduction announces

an Expert Panel Meeting to complete a review of seven phthalates on July 12-13, 2000.

The Center is completing a review of the following seven phthalate esters

butyl benzyl phthalate (85-68-7) BBP

di(2-ethylhexyl) phthalate (117-81-7) DEHP

di-isodecyl phthalate (26761-40-0, 68515-49-1) DIDP

di-isononyl phthalate (28553-12-0, 68515-48-0) DINP

di-n-butyl phthalate (84-74-2) DBP

di-n-hexyl phthalate (84-75-3) DnHP

di-n-octyl phthalate (117-84-0) DnOP

More details on the review can be found in the Federal Register announcement at http://ntp-server.niehs.nih.gov/Main_Pages/Announcements.html

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Further information about the NTP Center for the Evaluation of Risks to Human Reproduction and a summary of the complete review process can be obtained through the Center's web site: http://cerhr.niehs.nih.gov/

Louise Munk, editor of Chemical Awareness.

Renewed focus on the effects of phthalates on birth defects and impaired fertility indicate previously unknown risks!!

By: Finn Bro-Rasmussen, Professor, The Technical University of Denmark

Recent experiments with rats show that the concentrations needed to induce impaired fertility (semen quality) in laboratory animals are surprisingly low. After exposing female rats to phthalates during the particularly critical part of the gestation period (in humans corresponding to the last part of 1st trimester, the third month of pregnancy - a time when many women are hardly aware they are pregnant), researchers found that the androgen-producing tissues in male foetuses were damaged. They also indicated that such effects could perhaps be ascribed to the (previously unheeded) so-called short-chain phthalates (e.g. DEP and possibly DMP). Findings of phthalates in human blood and urine samples have been discussed for a while. Yet the data were seriously flawed until now, due to 'analytic contaminations' from laboratory equipment, cosmetics used by lab technicians, PVC floorings, paints, etc. But thanks to (among others) J. Brock's intensive analytic work it is now possible to produce results from which such misleading 'analytical contaminations' have been stripped out.

The new data indicate that human exposure to (notably) some types of  short-chain phthalates greatly exceeds previous estimates. Probably exposure is both direct (via short-chain phthalates used as additives e.g. in perfumery alcohol and cosmetics), and indirect (since they are formed in the human organism by degradation of the 'long-chain' phthalates, used to soften plastics, synthetic leather etc.

Along with this information the findings of additional studies have been published, done by the US EPA laboratories, Research Triangle Park, S. Carolina. They indicate that especially the short-chain phthalates are responsible for inhibiting the production of the male sexual hormone testosterone in rats.

Until now the main focus has been on the potential birth defects and impaired fertility associated with the use of di(2-ethylhexyl) phthalate (DEHP) and related 'long-chain' phthalates. However the extremely high concentrations of short-chain phthalates (DMP, DEP and in part DBP) found in blood samples from girls with premature breast development now indicate that there is a considerable and more general lack of knowledge regarding the hormonal effects of phthalates.

We cannot contend that all phthalates are demasculating; but as a minimum  those phthalates showing such an effect (e.g. DEHP, BBP, DINP, and DBP) should undergo joint assessment since their hormone disrupting effects are predictably almost certainly additive' (accumulative), according  to L. Earl Gray, a leading toxicologist at EPA Research Triangle Park, S. Carolina, USA. He also emphasizes that far too much remains uncertain regarding the modes of action and time aspects related to adverse effects. He thus underpins a statement earlier this year by Dr R. Kavlock, chairman of the US National Toxicology Program's Center for Risk Assessment of Endocrine Disrupters , saying that as yet no phthalate can be considered to have 'a clean bill' in terms of health risks.

Until now expert panels, both in Denmark and the EU, have been assessing the hormone disrupting effects of chemicals as 'traditional toxicological effects', that is with a threshold value referring to a given concentration, above which the substance is harmful. This approach ignores the fact that we do not know for a fact whether disturbances emerging during human puberty and sexual development could actually be the result of a previous chemical disruption, during a particularly critical and susceptible phase. The susceptible part of gestation could be such a particularly critical phase, and perhaps also the growth phase preceding puberty, i.e. the period when tissues and cells determining sexual differentiation develop.

It appears that the American researchers' read the present situation as a call for new concepts in the evaluation of phthalates, which they feel should be considered jointly, as a single group. In several quarters a demand for the phase-out of these widely used high-volume chemicals is now drawing near, while researchers naturally demand further studies. The Californian Health and Environment Authorities (Environmental Health Hazard

Assessment - the Proposition 65 Office) have announced that due to the potential risks of birth defects and reduced fertility they are considering the introduction of a warning label to be used on products containing DEHP.

Such a labelling could spur the industry to step up their development of necessary substitutes, at least for one substance among this large group of phthalates.