Phthalates are currently the subject of considerable media, legislative and scientific debate. Concerns have been raised on a variety of topics at regular intervals ever since the early 1980's. However, fears have repeatedly been shown to be unfounded.
Plasticised PVC has been used for over 50 years without a single known case of it having caused any ill-health and the environmental effects of phthalates are known to be minimal.
Academia and industry have continually worked together to address the concerns and conduct necessary research, making phthalates some of the most researched and best understood chemicals today.
Carcinogenicity
Some concerns have been expressed concerning carcinogenicity. In 1980s, liver tumour of rats and mice was reported upon an extremely high dosing of DEHP, but subsequent studies clarified that such effects are unique to rodents such as rats and mice and would not occur in primates such as monkeys.
In 2000, the International Agency for Research on Cancer (IARC: an affiliate organisation of World Health Organisation - WHO) re-classified DEHP from Group 2B to Group 3 in their carcinogenicity evaluation, thus clearly showing that DEHP is not carcinogenic to humans.
Tea and tap water (drinking water sterilised with chlorine) are also included in Group 3, which means that the carcinogenicity of DEHP is lower than that of coffee.
Plasticised PVC has been used for over 50 years without a single known case of it having caused any ill-health and the environmental effects of phthalates are known to be minimal
Endocrine Modulation
In past years concerns have been reported on about possible risks of PVC products related to endocrine modulation and alleged disruption of certain phthalates. In fact, there is no scientific evidence that any of the phthalate plasticisers are human endocrine disrupters. Some phthalates cause reproductive effects at high doses in rats and mice by a process that apparently involves the endocrine system.
However, these effects have only been seen at levels of exposure many times higher than those experienced by humans. Studies on non-human primates do not show adverse effects after high phthalate exposure. All the major phthalates have been comprehensively risk assessed by EU Member State experts who have conclusively agreed that they do not pose a risk to the general human population.
In Japan, the authorities have recently confirmed that phthalates should not be included among substances considered human endocrine disrupters.
Brief history of concerns:
During the early 1990’s, size reduction in penises of male alligators and their decreased headcount at Lake Apopka in Florida was reported, and the correlation between organic chlorine compounds and endocrine disruptive effects became the centre of concern.
Lake Apopka: There are many lakes in Florida, but this was the only lake that suffered pollution by water discharge from a nearby agricultural chemical plant. No such abnormalities were observed in alligators in other lakes of the region.
In July, 1991, the Wingspread Statement was announced, stating that “The release and use of toxic substances have had substantial unintended consequences affecting human health and the environment”, at a natural science expert meeting held in Wingspread, Wisconsin, U.S.
In 1996, Theo Colborn, Director of the Wildlife and Contaminants project at the World Wildlife Fund, published a book titled Our Stolen Future. The subtitle of the book reads “A scientific detective story”, suggesting, on the basis of already existing scientific information, that endocrine disruption is a serious current issue.
In October 1998 the European Parliament adopted a Resolution calling upon the European Commission to take action. The Commission published in December 1999 a “Community Strategy for Endocrine Disrupters” COM (1999) 706.
Its main objectives were to identify the problem, its causes and consequences and appropriate policy actions. A first progress report was published in 2001 (COM (2001) 262), and a second one in 2004 (SEC (2004) 1372).
What are “endocrine disrupters”?
When a specific chemical substance is taken into a living organism and affects the inherent hormonal functions, it is scientifically defined as an endocrine disrupting chemical or ‘endocrine disrupter’.
Hormones are generally defined as substances secreted by endocrine glands (hormone secreting organs) such as the pituitary and thyroid glands, and perform unique functions on specific target organs. These substances perform roles such as homeostasis i.e. keeping physical conditions at a constant state in order to cope with the environmental changes, or controlling differentiation and growth of tissues, and controlling the development of reproductive organs.
There are natural substances called phytoestrogens created by plants, which also act like estrogens in the body. The phytoestrogen intake is largely through food such as soya beans. Therefore upon estimating the effects of endocrine disrupters it is necessary to study the effects of phytoestrogens also.
Phytoestrogen: In the early 1940’s, infertility was observed in Australian sheep feeding on significant amounts of clover. This was due to the fact that a large quantity of a substance in clover had estrogenic effects. Isoflavones in soybean are well known as phytoestrogen and are also considered as good to the human body.
When a specific chemical substance is taken into a living organism and affects the inherent hormonal functions, it is scientifically defined as an endocrine disrupting chemical or ‘endocrine disrupter’
Actions at European Union Level
A study report entitled “Towards the establishment of a priority list of substances for further evaluation of their role in endocrine disruption preparation of a candidate list of substances as a basis for priority setting” was issued by BKH Consulting Engineers, NL, under contract to the European Commission, DG Environment.
The report focused on man-made chemicals used primarily in industry, agriculture and consumer goods and was completed in June 2000.
The study report identified a candidate list of 553 substances. Among these, BBP, DEHP, DBP, DIDP, DINP, Bisphenol A, tributyltin compounds, hexachlorobenzene, nonylphenol, various PCBs, dioxins and furans, perchloroethylene were identified as substances with evidence or potential evidence of endocrine disruption, already regulated or being addressed under existing EU legislation”.
Vinyl acetate, pentachlorophenol, nonylphenol ethoxylate, tertiobutylhydroxyanisole, intermediate and long chain chlorinated paraffins, DIBP, DOP, polyaromatic hydrocarbons, were identified as “Substances with insufficient data in the BKH report”. During a stakeholder meeting in November 2000 it was decided to retain all these substances for further evaluation.
A follow-up study addressed the 435 substances for which there was insufficient data in the 2000 report. 204 were classified as high production volume chemicals (HPV), persistent in the environment and to which human or wildlife exposure can be expected. In a second step, the endocrine disrupting effects in humans and wildlife has been evaluated.
This analysis leads to a list of 94 candidate substances with evidence of endocrine disruption, 53 with potential evidence of endocrine disruption and 57 with no scientific basis for inclusion in the list or insufficient data to decide. In a final step, the evaluation of the exposure concern to humans and wildlife resulted in a list of 84 substances with high-exposure concern, 5 substances with medium-exposure concern and 4 substances with low-exposure concern.
Substances identified as having high concern for exposure, belong to 34 different chemicals groups, including, chlorinated paraffins, phthalates, bisphenols, PAHs, PCBs and dioxins/furans.
The Commission has recently finalised a study concerning human exposure to endocrine disrupters through drinking water.
It has been noted in the study report that most of the European surface waters and some ground waters are contaminated with low levels of endocrine disrupters and that without adequate treatment steps, low levels of endocrine disrupters can be expected in drinking water.
The Commission has recently finalised a study concerning human exposure to endocrine disrupters through drinking water
Based on the scientific literature available, it was concluded that the contribution of drinking water to the total exposure of this group of chemicals to human beings is very low and many endocrine disrupters especially bio-accumulating compounds, are taken up by food in higher amount on a daily basis.
The study concluded that there is evidence showing that endocrine disrupting chemicals of low potency, such as organotin compounds, phthalates, bisphenol A and alkyl compounds can migrate from certain organic materials used, which are in contact with water intended for human consumption.
Assessments by the European Council for Plasticisers and Intermediates (ECPI) and academia of scientific studies carried out show that phthalates used in PVC and the low exposure that results from these applications pose no risk to humans or wildlife from endocrine activity. Following administration of various phthalates to pregnant rats an anti-androgenic effect on the testes of the male offspring was obtained.
The underlying mechanism is not fully understood and additional research is ongoing. Under all normal circumstances, however, exposure levels of people and wildlife are well below the concentrations that induced these effects in rats. There is therefore no risk to people or wildlife from phthalates in PVC applications.
The EU risk assessments for three of the mostly commonly used phthalates – diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) and dibutyl phthalate (DBP) – were published in 2005. The assessments showed no concerns for any current uses of DINP and DIDP. The third risk assessment, for dibutyl phthalate (DBP), shows some risk to plants in the vicinity of processing sites and to workers through inhalation.
But in both cases, these risks can be reduced by simple air treatment measures and personal protective equipment. The risk assessments are available on the European Chemicals Bureau web site (http://ecb.jrc.it) as well as on the Phthalates Information Centre web site www.phthalates.com.
The risk assessment for di-2-ethylhexyl phthalate (DEHP) was finalised in 2007 and published early 2008. Publication of the risk assessment for butylbenzyl phthalate (BBP) is expected in 2008.
