Policy relevant results from an expert elicitation on the health risks of phthalates

Background The EU 6th Framework Program (FP)-funded Health and Environment Network (HENVINET) aimed to support informed policy making by facilitating the availability of relevant knowledge on different environmental health issues. An approach was developed by which scientific agreement, disagreement, and knowledge gaps could be efficiently identified, and expert advice prepared in a way that is usable for policy makers. There were two aims of the project: 1) to apply the tool to a relevant issue; the potential health impacts of the widely used plasticizers, phthalates, and 2) to evaluate the method and the tool by asking both scientific experts and the target audience, namely policy makers and stakeholders, for their opinions. Methods The tool consisted of an expert consultation in several steps on the issue of phthalates in environmental health. A diagram depicting the cause-effect chain, from the production and use of phthalates to potential health impacts, was prepared based on existing reviews. This was used as a basis for an online questionnaire, through which experts in the field were consulted. The results of this first round of consultation laid the foundation for a new questionnaire answered by an expert panel that, subsequently, also discussed approaches and results in a workshop. One major task of the expert panel was to pinpoint priorities from the cause-effect chain according to their impact on the extent of potential health risks and their relevance for reducing uncertainty. The results were condensed into a policy brief that was sent to policy makers and stakeholders for their evaluation. Results The experts agreed about the substantial knowledge gaps within the field of phthalates. The top three priorities for further research and policy action were: 1) intrauterine exposure, 2) reproductive toxicology, and 3) exposure from medical devices. Although not all relevant information from the cause-effect chain is known for phthalates, most experts thought that there are enough indications to justify a precautionary approach and to restrict their general use. Although some of the experts expressed some scepticism about such a tool, most felt that important issues were highlighted. Conclusions The approach used was an efficient way at summarising priority knowledge gaps as a starting point for health risk assessment of compounds, based on their relevance for the risk assessment outcome. We conclude that this approach is useful for supporting policy makers with state-of-the-art scientific knowledge weighed by experts. The method can assist future evidence-based policy making.


Introduction
In the Henvinet project we focus on four types of health conditions, "asthma and allergies", "cancer", "endocrine disruption", and " neurodevelopmental disorders", and their associations with environmental exposures. This questionnaire is an evaluation of the quality of the scientific knowledge of various aspects of the cause-effect relationship between phthalates and endocrine disrupting effects. With your help we will evaluate the quality of the scientific knowledge of various aspects of the cause-effect relationship between phthalates in the environment and endocrine disruption in humans The goal is to identify knowledge gaps and areas of disagreement between you and your expert colleagues, as well as areas of agreement. Ultimately, the aim is to discuss the implications of these for policy and research.
The evaluation consists of two separate parts. In part A you will be asked to comment on the completeness and structure of a diagram illustrating our current understanding of the cause effect relationship. In part B you will be asked to express your confidence in scientist's ability to predict the magnitude of a variety of effects of phthalates in the environment.
Often experts feel uncomfortable answering the questions asked, as they feel that they must respond on the basis of a "gut feeling", setting aside the scientific basis. The scientific basis is carefully referred to in two different aspects of HENVINET reports: • The results of a detailed literature review are reported in order to explain and justify the causal diagrams produced; • Relevant literature is referred to in order to explain the basis for any disagreement and trends observed in the survey results.
The results of your evaluation and the evaluations conducted by other eminent authorities in the field will be discussed at a separate workshop within the Henvinet project consortium and with external experts.
We expect the entire exercise will take you about 10-15 minutes. We appreciate your participation very much and, on behalf of the Henvinet consortium we thank you for your time.
Part A. Evaluation of the structure and completeness of the causal diagram 1. Does the diagram take into account all of the important parameters when evaluating the risks related to production, use and discharge of phthalates? YES/NO If No, please explain: Part B. Evaluation of individual models or associations In the questions that follow you will be asked to express your confidence in scientist's ability to predict the concentrations, exposure and effects of phthalates. Insert a check mark where you feel it is appropriate.
It is important that you consider each question independently from the others. When answering a question do not take into account the state of knowledge in previous/other questions. As an annex to this questionnaire, you will find summary information related to individual questions, based on HENVINET scientific review to be published soon.

Questions about sources
1. What is your level of confidence in our data on the production volumes of phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

2.
What is your level of confidence in our ability to predict the magnitude of emission/release/leakage phthalates during production, transport and use?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

3.
What is your level of confidence in our ability to identify and quantify all different applications of phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

Questions about environmental matrices
4. What is your level of confidence in our ability to predict the concentration of phthalates in groundwater?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

5.
What is your level of confidence in our ability to predict the concentration of phthalates in sediments?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 6. What is your level of confidence in our ability to predict the concentration of phthalates in soil?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 7. What is your level of confidence in our ability to predict the concentration of phthalates in outdoor air?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 8. What is your level of confidence in our ability to predict the concentration of phthalates in indoor air and dust?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 9. What is your level of confidence in our ability to predict environmental transformation and biological half-lives for phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

Questions related to exposures
10. What is your level of confidence in our ability to predict the levels of exposure to phthalates in the general populations?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 11. What is your level of confidence in our ability to predict the main sources of exposure to phthalates for the general population?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 12. What is your level of confidence in our ability to identify and predict the levels of exposure to phthalates in highly exposed groups in the population?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 13. What is your level of confidence in our ability to identify and predict the main sources of exposure to phthalates in highly exposed groups?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 14. What is your level of confidence in our ability to predict the levels of oral exposure to phthalates in the general population?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 15. What is your level of confidence in our ability to predict the levels of oral exposure to phthalates in highly exposed groups?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 16. What is your level of confidence in our ability to predict the levels of inhalational exposure to phthalates in the general population?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 17. What is your level of confidence in our ability to predict the levels of inhalational exposure to phthalates in highly exposed groups?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 18. What is your level of confidence in our ability to predict the levels of dermal exposure to phthalates in the general population?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 19. What is your level of confidence in our ability to predict the levels of dermal exposure to phthalates in highly exposed groups?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

Questions related to toxicokintetics, toxicology and health effects
20. What is your level of confidence in our ability to predict the final concentrations in the target tissues, taking factors such as absorption, distribution, metabolism and excretion into consideration?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 21. What is your level of confidence in our ability to predict differences in toxicokinetics, in view of identifying sensitive groups (age, gender etc)?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.
22. Based on experimental studies, what is your level of confidence in our ability to predict adverse health effects caused by phthalates in a) Males?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. b) Females?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 23. What is your level of confidence in our ability to predict adverse health effects in humans caused by environmental exposure to phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 24. What is your level of confidence in our ability to predict the NOAEL of a) Single ortho-phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. b) Mixtures of phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 25. What is your level of confidence in our ability to predict adverse health effects in humans caused by environmental exposure to phthalates?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 26. What is your level of confidence in the validity of the claim that only/mainly ortho-phthalates (DEHP, DBP and BBP) have the potential to cause detrimental health effects?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct. 27. What is your level of confidence in the validity of the claim that phthalates and/or their metabolites cause endocrine disrupting effects in The reproductive system (Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.
The thyroid system?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.
The metabolic system?
(Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

Overall assessment
28. What is your level of confidence in our ability to predict harmful effects of phthalates in the environment and applications on human health?
? (Insert a checkmark in the appropriate box) 4. Very high confidence.
At least a 9 out of 10 chance of being correct.
At least an 8 out of 10 chance of being correct.
At least a 5 out of 10 chance of being correct.
At least a 2 out of 10 chance of being correct. 0. Very low confidence.
Less than a 1 out of 10 chance of being correct.

Final comments
The results will now be analysed and discussed by experts within the HENVINET consortium. Are there any comments you would like to make in closing to complete your evaluation? Perhaps you would like to comment on key areas of knowledge which you think are underdeveloped? Perhaps you would like to provide your impressions of the usefulness of this evaluation, or provide suggestions on how to improve it? Answer:

Sources
What is your level of confidence in our data on the production volumes of phthalates?
The total annual global production of all phthalates is estimated to be 3x10*6 tons, of which 2/3 is DEHP.
What is your level of confidence in our ability to predict the magnitude of emission/release/leakage phthalates during production, transport and use?
Phthalate esters and their metabolites are constantly detected in the indoor environment, consumer products, human urine, mother's milk and amniotic fluid.
Phthalates incorporated in PVC are not covalently bound and are therefore easily released into the environment.
What is your level of confidence in our ability to identify and quantify all different applications of phthalates?
Uses of various phthalates depend on their molecular weight (MW): • Higher MW phthalates such as DEHP, DiNP and DiDP are used as plasticizers to impart flexibility and durability in polyvinylchloride (PVC) products in construction material, clothing and furnishing. • Low MW phthalates such as DEP, DMP and DBP are used as solvents in cosmetics, insecticides, pharmaceuticals, construction materials, car products, clothing, food package, children products and medical devices.

Environmental matrix
What is your level of confidence in our ability to predict the concentration of phthalates in groundwater?
• Reported DEHP concentrations in ground water from the United States were reported as mean 15.7µg/l, range nd-470µg/l, while concentrations in Europe were 0.26µg/l with a range from <0.07µg/l to 1.4ug/l. Concentrations for drinking water in Europe ranged from <0.18µg/l to 3.5µg/l. Sample sizes were in the range from 2 to 9 samples investigated.
What is your level of confidence in our ability to predict the concentration of phthalates in sediments?
• DEHP concentration in sediments from Europe were found to be generally low with mean measurable reported concentrations of 4.9µg/g (range: 0.0001-487µg/g; n=405) • Microorganisms present in the sediments are responsible for the major routes of breakdown of DEHP • Sediment fingerprints of phthalates showed good correlation with per capita consumption for the high molecular phthalates.
What is your level of confidence in our ability to predict the concentration of phthalates in soil?
• Reported levels for DEHP from European countries were 48 µg/kg mean with a range of 4-5100 (n=3). In the US comparable concentrations ranged from 0.03µg/kg to 1280µg/kg (data points 1) What is your level of confidence in our ability to predict the concentration of phthalates in outdoor air?
• Concentrations of DEHP measured in Europe show a mean level of 21.9 ng/m 3 and a range of >0.28-1090 ng/m 3 (n=85). • DEHP concentrations were found to be 1000 times lower in outdoor than in than indoor air in a Japanese study • Air concentrations were found to be higher in summer than in winter, probably due to enhanced vaporization from plastics.

• Atmospheric transport is important for the presence of phthalates in the Arctic
What is your level of confidence in our ability to predict the concentration of phthalates in indoor air and dust?
• Phthalates and their metabolites are constantly detected in the indoor environment.

•
Indoor air DEHP concentrations are found to be up to 1000 times higher than in outdoor air and reached a maximum of 3.13ug/m 3 . The air in 27 houses around Tokyo was measured in the study. • However, studies from Europe showed a mean indoor air concentration for DEHP of 245 ng/m 3 with a range of 18-1046 ng/m 3 (n=398). The levels in dust were found to be within a range of 0.002-4.58 g/kg and have a mean concentration of 0.62 g/kg (n=55). • A Norwegian study found higher concentrations of DBP in indoor dust of different particle sizes than DEHP. The concentration varied a 10-fold between different sample sites. • PVC floors are a potential source for phthalates in indoor air; however, PVC-coated wall coverings are found not to release sufficient quantities to lead to intake in the range of the acceptable daily intake (ADI) values.
What is your level of confidence in our ability to predict environmental transformation and biological half-lives for phthalates?
• Phthalates monoesters have a biological half-life of approximately 12hrs. • Microorganisms present in sediments provide a major route of breakdown of DEHP • Degradation half-life of DEHP in wastewater is 1.6 days.

Exposures
What is your level of confidence in our ability to predict the levels of exposure to phthalates in the general populations?
• DEHP exposure was estimated in 2000 to be 3-30 µg/kg body weight / day for adults, 2-3 times higher for children. • More than 90% of the estimated DEHP intake for adults is from food, whereas formulafed and breast-fed babies retain only 44% and 60% of the total DEHP from food. • Reduction of DEHP exposure by 40% from 1996 -2003 in Germany.
• Median total intake of DEHP range from 8.2µg/kg bw/day in adults up to 25.8µg/kg bw/day in toddlers. • The secondary DEHP metabolites in urine give a more accurate estimate of the DEHP exposure than the primary monoester.
What is your level of confidence in our ability to predict the main sources of exposure to phthalates for the general population?
• The main source of exposure for the general population is through ingestion of contaminated food through production and packaging.
• DEHP dust concentrations and children with doctor-diagnosed asthma were significantly correlated (Swedish study).
What is your level of confidence in our ability to predict the levels of dermal exposure to phthalates in highly exposed groups and the general population?
• No human in vivo dermal absorption studies are available.
• In vitro comparisons show that absorption occurs more rapidly through rat skin than human skin. • In guinea pigs only 3% and 21% was absorbed and excreted after 1 and 7 days, respectively.

Toxicokinetics
What is your level of confidence in our ability to predict the final concentrations in the target tissues, taking factors such as absorption, distribution, metabolism and excretion into consideration?
• Most data are gained from animal studies, human data are scarce.
• There is high variability between species in toxicokinetics.
• No significant accumulation of phthalates in organs and tissues, less than 1% retained.
• Distributed throughout the body with the blood to all tissues.
• Highest concentrations of DEHP have been measured in liver and kidney.
• The orally ingested di-ester phthalates are metabolized into monoesters by non-specific esterases and lipases, and then further by various oxidation and hydroxylation reactions resulting in secondary metabolites. • Most of the orally ingested phthalates (70%) are excreted in the urine as secondary metabolites in a male human study, and only 13% is excreted as primary monoesters. • Secondary metabolites are more accurate biomarkers of exposure, compared to the primary monoesters, since the secondary metabolites account for most of the excreted phthalates.
What is your level of confidence in our ability to predict differences in toxicokinetics, in view of identifying sensitive groups (age, gender etc)?
• Exposure studies in humans measuring primary and secondary metabolites suggest agerelated differences in metabolism and/or clearance. • Premature and term infants have reduced renal clearance, due to lack of glucuronidation pathways, which may increase the internal dose of toxic metabolites. Also human neonates have less pancreatic lipases. • Sex and ethnicity does not matter for toxicokinetics of phthalates.
• High inter-species variability exists in the first step of biotransformation (lipases) of phthalates.

Toxicology/ Health effects
Based on experimental studies, what is your level of confidence in our ability to predict adverse health effects caused by phthalates in c) Males? d) Females?
• Effects of exposure are best studied in males; however, a few studies also look at female reproduction.
• Pathological changes in male reproductive organs and lower testosterone levels have been observed when the animal is exposed prenatally (50 mg/kg DBP or 10 mg/kg DEHP). Increased testosterone levels are seen after postnatal exposure (10 mg/kg bw/day from PND 21-120).

•
Reduction of prenatal maternal weight gain and number of pups and increase in postnatal mortality has been observed after exposure to high doses (750 and 1500mg/kg bw/day from GD 3-PND 21). Increased nipple sizes in male offspring were seen at all dose levels (375-1500 mg/kg bw/day) and are also seen in other studies, while accessory reproductive organ developmental effects seen at highest doses. No effects seen in female offspring of this study.

•
Reduction of Sertoli cell proliferation and increase in multinucleated germ cells and interstitial hyperplasia, depletion of germinal tubule and decreased seminiferous tubule diameter are findings in lower doses (>100 mg/kg single dose, 100-500 mg/kg bw/day) when exposed during development.

•
Low doses (14-23 mg/kg bw/day) have caused small reproductive organ sizes in F1 and F2 generations of male rats, without any histological changes or other adverse reproductive effects.

•
Effects on male reproductive organs are similar in animals exposed to a single dose and animals exposed to multiple doses during pre-and postnatal development.

•
In females, exposure to DEHP before and during puberty (>=500 mg/kg bw/day) increased serum estradiol, advanced onset of puberty and increased ovarian and uterine weight in marmosets, while also lower doses of 2 mg/kg decreased levels of estradiol and led to disturbances of normal ovarian function in adult rats.
What is your level of confidence in our ability to predict adverse health effects in humans caused by environmental exposure to phthalates?
• Few studies have reported a relationship between environmental exposure and human health.

•
Animal studies support the hypothesis that there is a relationship between environmental exposure and human health.

•
Effects observed in rat studies resemble testicular dysgenesis syndrome in humans • Levels of phthalates have been negatively associated with sperm parameters and testosterone and LH concentrations.

•
In females, higher levels of phthalates have been associated with endometriosis in a few studies.

•
In human boys of 2-36 months of age, a negative association between anogenital distance and phthalate metabolites in their mothers' urine has been detected.
What is your level of confidence in our ability to predict the NOAEL of c) Single ortho-phthalates? d) Mixtures of phthalates?
• The Scientific Committee on Toxicity, Ecotoxicity and the Environment (CSTTEE) support the suggested new NOAEL of DEHP of 4.8 mg/kg bw/day for testicular and developmental toxicity, which was found to be the most sensitive endpoint (2004).

•
The same committee recommended using not only MEHP, but also 5-OH-MEHP and 5oxo-MEHP for biomonitoring • Sensitivity in different species seems to differ considerably. E.g. in mamorsets no testicular effects were seen at a dose of 2500 mg/kg bw/day. This is explained by a lower absorption from marmoset intestines than from rodent intestines. Rodent liver peroxisome proliferation is regarded not relevant for human risk assessment as rodents are highly sensitive to this phenomenon and that the critical effects of DEHP relate to reproduction.

•
A few experimental studies in rats published after 2005 suggest a similar mechanism of action for DEHP, BBP, DBP and DiBP on foetal testicular testosterone production and for DiBP, DEHP, DBP and DiNP on foetal testicular testosterone production and testicular histopathology, but this has not been related to other effects What is your level of confidence in our knowledge of the mechanism(s) of action of a) Parent phthalate compounds? b) Phthalate metabolites?
• A study has shown that only unmetabolized phthalates have affinity for steroid receptors, not the absorbed monoesters. This indicates a lack of receptor-mediated effects in vivo. • MEHP has shown to be a more potent testicular toxicant than the parent compound DEHP. MEHP readily crosses the placenta • Reduced testosterone concentration following DEHP or DBP might be due to reduced expression of genes involved in steroidogenesis. Phthalates also interfere with expression of other genes involved in testicular descent and cell cycle, causing decreased proliferation, eg of Sertoli cells.

•
Peroxisome-proliferatior-activated receptors (PPAR), which are involved in metabolism, cell growth and stress responses, may be involved in testicular toxicity following phthalate exposure. PPAR is probably also responsible for reduced levels of aromatase and thus estradiol.
What is your level of confidence in the validity of the claim that only/mainly ortho-phthalates (DEHP, DBP and BBP) have the potential to cause detrimental health effects?
• The general consensus is that only ortho-phthalates with side-chain length of C4-C6 including DEHP, DBP and BBP have potential to disrupt normal development and reproduction.

•
Findings have suggested that these phthalates are endocrine disruptors affecting development, reproductive and thyroid hormonal axes and may contribute to the increase in prevalence of metabolic syndrome.

•
Few studies with the other phthalates are available.
What is your level of confidence in the validity of the claim that phthalates and/or their metabolites cause endocrine disrupting effects in a) The reproductive system b) The thyroid system? c) The metabolic system?
• Pathological changes in male reproductive organs and lower testosterone levels have been observed when the animal is exposed prenatally (50 mg/kg DBP or 10mg/kg DEHP). Increased testosterone levels are seen after postnatal exposure (10 mg/kg bw/day from PND 21-120).
• Increased nipple sizes in male offspring were seen at all dose levels (375-1500 mg/kg bw/day) and are also seen in other studies, while accessory reproductive organ developmental effects seen at highest doses • Reduction of Sertoli cell proliferation and increase in multinucleated germ cells and interstitial hyperplasia, depletion of germinal tubule and decreased seminiferous tubule diameter are findings in lower doses (>100 mg/kg single dose, 100-500 mg/kg bw/day) when exposed during development • Low doses (14-23 mg/kg bw/day) have caused small reproductive organ sizes in F1 and F2 generations of male rats, without any histological changes or other adverse reproductive effects.

•
In females, exposure to DEHP before and during puberty (>=500 mg/kg bw/day) increased serum estradiol, advanced onset of puberty and increased ovarian and uterine weight in marmosets, while also lower doses of 2 mg/kg decreased levels of estradiol and led to disturbances of normal ovarian function in adult rats • Effects observed in rat studies resemble testicular dysgenesis syndrome in humans • Levels of phthalates have been negatively associated with sperm parameters and testosterone and LH concentrations.

•
In females, higher levels of phthalates have been associated with endometriosis in a few studies.

•
In human boys of 2-36 months of age, a negative association between anogenital distance and phthalate metabolites in their mothers' urine has been detected.

•
Normal thyroid hormone function has been shown to be important for reproductive system development in females and males.

•
Thyroid hormone and TSH levels were inversely correlated with urinary MEHP concentration in humans and animal studies also indicate an association between DEHP exposure and thyroid hormones. • Significant positive correlations between waist circumference and urinary phthalate metabolites are found in American men.