Endocrine-disrupting chemicals, studies

Roberts, J.A. (2008a) New Chemical Bodies A Conversation on Human Biomonitoring and Endocrine-disrupting Chemicals , Studies in Sustainability, Philadelphia, PA ... 

Mechanistic studies to identify how endocrine disrupting chemicals interact with hormone systems are required. Although population effects coupled with biomarkers of exposure are strongly suggestive of endocrine disruption, the effect could be secondary to metabolic toxicity. Establishing mechanisms may avoid the need to make decisions on a weight of evidence approach alone. 

A summary is presented of a revised strategy on endocrine-disrupting chemicals set out in a progress report by the European Commission in June 2001. The need for suitable test methods is discussed. Anew study will be conducted into the occurrence of endocrine disrupters in drinking water. 

It helps them to reduce systematically their use of hazardous chemicals and develop new products. Some companies have agreed on substances that need to be avoided. As documented In the case studies In Annex I of this report, they are Instructing their suppliers to phase out a range of carcinogenic, mutagenic and reproductive toxins, as well as some persistent, bloaccumulative, and endocrine disrupting chemicals. 

Depending upon the circumstance and desired effects, endocrine-disrupting chemicals can be either good or bad. The endocrine system is a finely balanced system responsible for fertility and many of the feminine and masculine traits we are all familiar with. Endocrine disruptors are used by millions of women in the form of the pill to control fertility. Chemicals in birth control pills subtly manipulate the endocrine system to reduce fertility. Unfortunately, we now know that many chemicals are capable of influencing the endocrine systems. When these chemicals, such as DDT and TCDD, are released into the environment, they reduce the fertility of wildlife. Exposure to endocrine disruptors is linked to decreased fertility in shellfish, fish, birds, and mammals. Endocrine disruptors such as nonylphenol have been shown to feminize male fish, interfering with reproduction. Some studies have also linked exposure to endocrine disruptors to decreases in human male sperm count. Ironically, urinary metabolites of the birth control pill as well as the female hormone estrogen pass through waste treatment plants and are released into the aquatic environment, where even small concentrations cause feminization of male fish. 

Viet, P.H., Hoai, P.M., Hung, P.T., Lieu, T.T., 2000. Persistent organochlorines in environment of coastal hydrosphere A case study in Vietnam. The UNU International Symposium on Endocrine Disrupting Chemicals (EDCs). Environmental Governance and Analytical Techniques—EDCs in East Asian Coastal Hydrosphere. University of Malaya, Kuala Lumpur, Malaysia, 17-18th April. 

Nasu M, Goto M, Oshima Y, et al. 2001. Study on endocrine disrupting chemicals in wastewater treatment plants. Water SciTechnol 43(2) 101-208. 

Most developmental neurotoxicity studies have focused on general impairment of behaviour, but some studies have also found evidence for effects on sexual dimorphic behaviour. Hormones play a central role in central nervous system development, including the sexual differentiation of the brain. Studies on hormones and various endocrine disrupting chemicals (particularly those with estrogenic or antiandrogenic effects) have shown that the developing brain may be susceptible to disturbances in sexual behaviour. Therefore, effects on one sex but not the other should not be dismissed, but must be evaluated in the context of effects on sexual differentiation of the brain. 

Okazaki K, Okazaki S, Nakamura H, Kitamura Y, Hatayama K, Wakabayashi S, Tsuda T, Katsumata T, Nishikawa A, Hi-rose M (2002) A repeated 28-day oral dose toxicity study of genistein in rats, based on the Enhanced OECD Test Guideline 407 for screening endocrine-disrupting chemicals. Arch Toxicol 76 553-559 Sandow J (1979) Toxicological evaluation of drugs affecting the hypothalamic-pituitary system. Pharmac Ther 5 297-303... 

Fernandez MF, Olmos B, Granada A, Lopez-Espinosa MJ, Molina-Molina JM, Fernandez JM, Cruz M, Olea-Serrano F, Olea N. 2007b. Human exposure to endocrine disrupting chemicals and prenatal risk factors for cryptorchidism and hypospadias a nested case-control study. Environ Health Perspect 115(Suppl 1) 8—14. 

Studies to identify endocrine-disrupting chemicals. Physicochemical profile. 

Mixtures of endocrine disrupting chemicals have been shown to produce additive, synergistic, and unexpected dose-response effects. The following studies are illustrative of the effects noted. 

In an in vitro study, mixtures of six synthetic endocrine disrupting chemicals and plant-derived phytoestrogens were evaluated for estrogenic activity The EDCs were... 

The most common phthalate plasticisers are di-2-ethyl hexyl phthalate (DEHP), di-isodecyl phthalate (DIDP), and di-isononyl phthalate (DINP). Phthalate use has been controversial for years becanse of its snspected health hazards, especially in the case of DEEIP. In both wildlife and laboratory animals, phthalates have been linked to a range of reproductive health effects, with claims that most of them can function as an endocrine disrupting chemical (EDC), and also as cancer-causing agents (specifically in the liver and kidneys). Snch negative effects that phthalates are suspected to have on health have been attribnted to short ester chains (< C9). In fact, phthalates are already distributed worldwide in the environment. Some phthalates are even found in deep-sea jellyfish 1,000 meters below the surface of the North Atlantic Ocean. A number of studies have shown that most people are probably contaminated by substantial quantities of these chemicals, and yet for hnmans, no safe level of exposure to phthalates has been determined. There are also claims about the leaching of certain phthalate plasticisers from biomedical plastics (e.g., intravenous tubes) and hence directly into the patients bloodstream. In one snch stndy, it was shown that about 60% of the DEHP/DOP had migrated to the patient, while almost all of the bis (2-ethylhexyl) adipate (DOA) has been retained in the tnbe [28]. 

Manganese-oxide materials have been reported as efficient oxidants for the degradation of endocrine disruptive chemicals such as estrone, 17jS-estradiol, bisphenol A and bisphenol F, among others. Xu et al. studied the oxidative removal of several endocrine disruptors from water using synthetic 5-Mn02 (surface area = 128 m g ) as well as the factors that influenced its... 

In a study of mice that consumed drinking water containing uranium, estrogen-like effects were observed. It was reported that exposure to uranium that is an endocrine-disrupting chemical may increase the risk of fertility problems and reproductive system cancer (Raymond-Whish et al. 2007). There are no such studies of these effects on humans. 

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