Version 1.0 Endocrine Disruptors: playing havoc with our hormones Rachel Carson shocked What is the endocrine exposed during use. No one – from the world in her landmark system? the unborn to the oldest – has escaped book Silent Spring back in 1962 The endocrine system is a complex exposure. To date, a large and growing with a detailed scientific account of network of glands that produce and number of chemicals have been the devastating effects of synthetic secrete the hormones that regulate implicated as endocrine disruptors. chemicals on the reproductive systems all the major body functions in birds, These include: and behaviour of fish and reptiles. reptiles and mammals, including Phthalates are a group of chemicals At the time, the evidence presented was humans. The most important of these identified as having endocrine disrupting not well accepted, much less recognized functions are growth, development capability. Their primary use is in by industry, government and academia. and reproduction. The main endocrine plastics, as a softener, but they also have Eventually though, government officials glands include the pituitary that application in perfumes, cosmetics, and industry leaders were forced to regulates the other endocrine glands; hairsprays, lubricants and finishers. acknowledge the legitimacy of this the thyroid, that controls metabolic rate; Alkylphenols and their derivatives work. With publication in 1995 of Our the parathyroid that regulates blood are yet another group of chemicals Stolen Future, evidence of the profound calcium; the adrenals, that manage the known to disrupt endocrine function. effect of endocrine disruptors on normal body’s fluid balance; the pancreas, that Alkylphenols are used as detergents and growth and development in wildlife and regulates blood sugar; the pineal gland, as plasticisers and stabilizers in plastics. humans could no longer be ignored. that is believed to moderate biorhythms and moods and stimulate the onset of Bisphenol A, also an alkyl phenol, Today, new results, new modes of puberty and lastly, the gonads is a component of epoxy resins and action and new perspectives have (ovaries in females and testes in males) polycarbonate plastics used to package triggered almost daily reports on how that control the development of sex food and drinks. It has also been chemicals disrupt the endocrine system. characteristics and functioning of sex employed in the resins that commonly In the past several years, six broad and organs. coat food cans, bottle caps and water disconcerting trends have emerged. supply pipes. • All living birds, mammals and How do endocrine Polychlorinated biphenols or PCBs humans alive today have been have been used since 1929 as heat exposed. disruptors alter hormone function? transfer fluids in transformers and as • Laboratory experiments with dielectric fluids in capacitors. PCBs animals show that exposures An endocrine disruptor is a synthetic are persistent in the environment, to endocrine disruptors have chemical that when absorbed into the resistant to biodegradation and tend to impacts at levels far below body can disrupt normal hormone accumulate in living organisms, with those that had been considered functioning. There are four main those highest in the food chain most possible. mechanisms by which endocrine affected. disruptors can alter normal hormone • Many more systems governed function. Dioxins and furans are similar in by hormones – perhaps all structure to PCBs. These chemicals are chemically mediated message They can: not manufactured but are created during systems are now considered • mimic or partially mimic the incineration and also display endocrine vulnerable to endocrine sex steroid hormones (estrogens disrupting capabilities. disruptors. and androgens) by binding to Brominated flame retardants or BFRs • Many more compounds are hormone receptors or influencing are a group of chemicals added to now known to act as endocrine cell signalling pathways; consumer goods such as electronics and disruptors. • block, prevent and alter hormonal textiles to reduce the potential for fire. The heating and burning of materials • Human health effects have binding to hormone receptors containing these chemicals can produce recently been expanded to or influencing cell signalling by-products known to alter endocrine include impacts of adult exposure pathways; function. to endocrine disruptors on fetal • alter the production and development. degradation of natural hormones; Pesticides’ power to disrupt normal hormonal functioning is well • Traditional toxicological and documented. This is particularly methods, emphasizing the dose- • modify the creation and function true of DDT, a pesticide banned in response curve, have proven of hormone receptors. the industrialized world, but still ineffective in studying endocrine manufactured and sold to developing disruptors. How are we exposed? countries. Today, synthetic chemicals with known Heavy metals such as lead, mercury and or suspected endocrine disrupting cadmium have been known to impact capabilities are pervasive in our air, fetal brain development and functioning water and food. Workers manufacturing for hundreds of years. Mothers exposed products containing these chemicals to these metals through environmental are also exposed in the workplace and releases from the mining, chemical and citizens purchasing these products are power industries or from consumption of contaminated food and water have inadvertently exposed and affected their unborn children. What are the health What can be done? This legal instrument aims to phase out and eventually eliminate the ‘dirty dozen’ effects? Addressing the concerns associated of persistent organic pollutants, including Most of the evidence accumulated to with endocrine disruptors is one of endocrine disrupters like PCBs, dioxins and date on the health effects associated the greatest challenges the human furans and DDT. To their credit representatives with exposure to chemicals that race faces this decade and beyond. of Canada were the first of 50 countries disrupt the endocrine system comes It will take individual and collective needed to ratify the Stockholm Convention. from observations and studies of action. Informed consumer choices for To date 24 countries have followed Canada’s wildlife. Within this group, the instance, can help. Limiting, wherever lead. Meantime, several ratifying countries embryo and fetus, whose growth and possible, the purchase and use of are not content to wait until the Convention development are closely regulated products that were produced using these comes into effect, they are moving ahead with by the endocrine system, appear chemicals or contain these chemicals implementation now. particularly vulnerable to exposure to is an important step. But rethinking chemicals with endocrine disrupting the way these chemicals are made and The benefits of such actions are great because capability. Females exposed to these used in the first place is clearly the most exposure to these chemicals has not yet chemicals can pass them to developing effective approach. altered genetic material, only how genes are expressed, and the damage seen today can be offspring, either in eggs (amphibians, Efforts to move in this direction are reversed. The next generation need not suffer reptiles, birds) or the womb (mammals) gaining hold worldwide. Dr. Michael reduced intellectual, immune or reproductive and after birth through breastfeeding. Braungart, a German chemist and capacity. If exposure to endocrine disruptors So while adult animals may not William McDonough, an American can be eliminated, future generations have the display ill effects, their offspring architect, leaders in this new approach, opportunity to grow and develop, once again, may suffer lifelong health effects have recently proposed guidelines in the way nature intended. including modified immune systems, that advocate reducing the number of altered sexual behaviour, reduced chemicals used in a given product, fertility, masculinization of females, only manufacturing products with EDITOR’S NOTE: feminization of males, malformed known chemical components and fallopian tubes, cancers of the refraining from producing products The Workers Centre offers many training uterus, cervix and male and female that don’t quickly and easily degrade programs on issues related to endocrine reproductive tracts. in the environment. This approach disruptors. Also be sure to visit the World Information obtained from also proposes intelligent design and Wildlife Fund website www.wwf.ca for investigations of human populations manufacture of products, handling information on their endocrine disruptors is strikingly similar. Exposure to material in the same way nature campaign, and www.greenhealthcare.ca for chemicals displaying endocrine recycles waste. information about the Canadian Coalition of disrupting properties has been related Green Health Care’s efforts to promote PVC- Some practical examples include and mercury-free alternative products. to a wide range of problems including work completed by fabric and car impaired reproductive patterns and manufacturers. DesignTex, a New York reduced endocrine, immune and based group of textile designers and central nervous system functioning. distributors, recently developed a new Also cancers of the reproductive process using fewer chemicals and none system (prostate, testicles, ovaries, with known toxicological properties, endometrium and female breast) now