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Endocrine Disruptors : Questions on Endocrine Disruptors

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Scientific Facts on Endocrine Disruptors

This study is a faithful summary of the" Global Assessment of the state-of-the-science of Endocrine Disruptors" ,

a leading scientific consensus report produced in 2002

by the IPCS (International Programme on Chemical Safety).

The study is written in a language for non-specialistsand structured in 3 levels of increasing detail.

More info on our 3-level structure

Questions on Endocrine Disruptors

1. What are Endocrine Disruptors (EDCs) ?

2. How do EDCs act ?

3. Do EDCs affect wildlife ?

4. Do EDCs affect human health ?

5. What are potential sources of EDC exposure ?6. Conclusions

7. Other views on Endocrine Disruptors

GreenFacts 3-Levels Structure

Our Endocrine Disruptors study is structured into 3 levels of increasing detail:the SUMMARY, the DETAILS and the SOURCE.

Click below on the level you want to access.

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Endocrine Disruptors : Level 1 - Summary on Endocrine Disruptors

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Info on our studies structure

Level 1 - Summary on Endocrine Disruptors

1. What are Endocrine Disruptors (EDCs) ?2. How do EDCs act ?



5. What are potential sources of EDC exposure ?

6. Conclusions


Level 1 Questions More in Details

Next Question Top

. What are Endocrine Disruptors (EDCs) ?

1.1 The endocrine system is a set of glands and the hormones they produce, which help guide the development,

growth, reproduction, and behaviour of animals and humans. Some hormones are also released from parts of thebody that are not glands, such as the stomach, intestines or nerve cells, and act closer to where they are released.

More...

1.2 Some chemicals, both natural and man-made, can interfere with endocrine glands and their hormones or where

the hormones act - the target tissues. These chemicals are called endocrine disruptors or endocrine disrupting

chemicals (EDCs). More...

1.3 The presence of EDCs in our environment raises concerns because:

q harmful effects have been observed on reproduction, growth and development in certain species of wildlife,

q there are increases in some human reproductive disorders and some cancers which could be related to

disturbance of the endocrine system, andq adverse effects from some environmental chemicals known to act on the endocrine system have been

observed in laboratory animals. More...

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Conclusion Level 1 Questions More in Details

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2.1 Endocrine disrupting chemicals (EDCs) can act in a number of ways in different parts of the body, they may:

q reduce the production ofhormones in endocrine glands,

q affect the release of hormones from endocrine glands,q copy or counteract the action of hormones at target tissues, or

q speed up the metabolism of hormones and so reduce their action.

In many cases, it is not yet clear exactly how EDCs act, even in some cases where a link has been shown betweenEDC exposure and an adverse effect. More...

2.2 What has been established mainly in the laboratory is:

q exposure to EDCs during early development (e.g. in the womb, during childhood) may cause permanenteffects,

q exposure to EDCs during adult life may not show any significant or visible effects,q exposure to EDCs may produce varying effects depending upon the stage of the life cycle or even the seaso

andq unforeseen effects may occur in the target tissues due to endocrine interactions. More...

2.3 The most controversial issue is whether low level exposures to EDCs can have adverse effects. Some scientists

have found effects at low doses in laboratory experiments, while others have not been able to corroborate these

findings. Some say that traditional testing methods are not robust enough to pick up low-dose effects. These areimportant issues to resolve because of the presence of low levels of EDCs in the environment. More...


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Certain endocrine disrupting chemicals (EDCs) have affected reproduction in wildlife populations. While some EDCs

disappear quickly from the natural environment, others persist and these have been the most studied. Aquaticanimals are particularly affected, especially carnivores, because they are at the top of the food chain where highlevels of persistent chemicals build up over time.

3.1 Some examples of effects in wildlife include:

q reduction in the population of Baltic seals,q eggshell thinning in birds of prey,q decline in the alligator population in a polluted lake,q reduction in frog populations,

q adverse effects on fish reproduction and development, and

q development of male sex organs in female marine animals such as whelks and snails.More...

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The effects in seals, birds and alligators are most likely due to EDCs such as PCBs, dioxins, DDT/DDE and other

pesticides that contain chlorine. The effects on fish appear to be caused by oestrogens in the water flowing fromsewage treatment works into rivers. The effects on marine whelks and snails are due to the use of TBT tributyltin

in anti-fouling paints on boats and ships.

3.2 Overall, the current evidence shows that certain effects seen in wildlife can be attributed to EDCs. Most effectshave been observed in highly contaminated areas. Moreover, in many cases where wildlife has been affected, it is stnot known how the EDC is working to bring about these effects. More...


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At the moment there is no firm evidence that environmental endocrine disrupting chemicals (EDCs) cause healthproblems at low levels ofexposure. However, the fact that high levels of chemicals can impair human health throug

interferences with the endocrine system, raises concerns about the possible harmful effects of mixtures of so called

endocrine disrupting chemicals, even at low background-levels. More...

4.1 It has been suggested that in humans EDCs may be causing:

q reductions in male fertility,q abnormalities in male reproductive organs,

q female reproductive diseases,q earlier puberty, andq declines in the numbers of males born. More...

4.2 Some EDCs may affect development of the nervous system and the immune system. More...

4.3 As yet, there is no substantial evidence to show that exposure to environmental EDCs causes cancer, such asbreast cancer, uterine cancer, testicular cancer, prostate cancer or thyroid cancer. More...

4.4 However, it is plausible that EDC exposure could be harmful to humans and could be a reason for some of theincreases in human disorders mentioned above, but more research is needed to investigate this possibility. More...


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Most of the information on exposure to endocrine disrupting chemicals (EDCs) has focused on the presence of so-

called persistent organic pollutants in lakes, rivers and seas. Exposure of humans can occur via contaminated foodor water, combustion sources from industrial processes and burning of waste and chemicals used in consumerproducts. Humans are also exposed to natural oestrogens from plants that are found in foods like soya. More...


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Next Question Top

6. Conclusions

6.1 There is some evidence that humans are vulnerable to endocrine disrupting chemicals (EDCs) at high levels ofexposure. However, effects from exposure to long-term and low-level EDCs have yet to be proven. More...

6.2 Evidence suggests that wildlife has been harmed by EDCs, especially aquatic species in highly polluted areas.More...

6.3 Present knowledge of effects on wildlife and humans is insufficient. Further research is needed to betterunderstand this important issue. More...


Top


This summary is based on the latest International Programme on Chemical Safety (IPCS) review, " Global

Assessment of Endocrine disruptors". It is considered by most scientists as a consensus document and other recent

scientific assessments reach similar conclusions. However, some people and organizations propose different views:

q Positions suggesting that Endocrine Disruptors pose more risk.

q Positions suggesting that Endocrine Disruptors pose less risk.

Conclusion Level 1 Questions

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Endocrine Disruptors : 1. What are Endocrine Disrupters ?

ome > Studies > Endocrine > Level 2 > Question 1


The answers to Question 1 are taken from: IPCS " Global Assessment of Endocrine disruptors"

Endocrinology and Endocrine Toxicology (Chapter 3)

Level 1 Questions Next Question

. What are Endocrine Disruptors (EDCs) ?

1.1 What is the endocrine system ?

1.2 What is the definition of endocrine disruptors ?

1.3 Why is there concern about endocrine disruptors ?

.1 What is the endocrine system ?

The endocrine system is a complex system consisting of glands in the body that produce hormones. Examples are t

thyroid gland in the throat, the pituitary gland in the brain, the adrenals, pancreas and ovaries in the abdomen, and

the testicles, which lie outside the abdomen.

Hormones act as chemical messengers, controlling many basic functions, such as growth, development, reproductiohow food is utilised in the body, blood pressure, blood glucose levels and fluid balance. Examples of hormones areinsulin from the pancreas, which controls blood glucose, and the sex hormones, oestrogen from the ovary andtestosterone from the testicles, which affect reproductive function.

Hormones are carried in the blood stream to distant target organs or cells where they perform particular functions.

Examples are the pituitary hormone from the brain which causes the ovary to release an egg, or the hormones from

the adrenal gland which prepare the body to face stress. Other hormones are released within an organ or tissue a

collection ofcells related by their functions and act locally within the organ or tissue, such as preventing an egg

maturing in the ovary.

The endocrine system also includes a third group of hormones called neurohormones which are released by nerve

cells either locally or into the blood stream where they act further away. More

The following animation illustrates how the glands of the endocrine system aredistributed in the human body. To find out more point your mouse to the glands in the image.

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.2 What is the definition of endocrine disruptors ?

Endocrine disruption is not, in itself, a measure oftoxicity the occurrence ofadverse health effects. Rather, it is

considered to be a change that may lead to harmful effects. For example, a potential endocrine disruptor (pED) is a

foreign substance or mixture that possesses properties that might be expected to lead to endocrine changes in anindividual life form, in its offspring, or in populations.

An endocrine disruptor (ED) is, therefore, defined as a foreign substance or mixture that alters function(s) of the

endocrine system, consequently harming an individual life form, its offspring, or populations. More.

Please note that there is no widely accepted list of endocrine disruptors or potentialendocrine disruptors and that the IPCS document summarised here does not provide such list.The European Commission is developing a candidate list of substances in order to set priorities

for further evaluation of their role in endocrine disruption (COM(2001) 262 final)

The following animation illustrates only one of the ways in which EDCs can act.Click the play button to start the animation

Source: EMCOM " http://www.emcom.ca/EM/humans.shtml"

Back to Summary Level 2 Questions More in the Source Document

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.3 Why is there concern about endocrine disruptors ?

Recent years have seen growing concern among scientists and the public at large about endocrine disruptingchemicals (EDCs) that may interfere with the endocrine system and cause harmful effects.

The presence of EDCs in our environment raises concerns because:

q harmful effects have been observed on reproduction, growth and development in some species of wildlife,

both aquatic and terrestrial,q there are increases in some human reproductive disorders and some cancers which could be related to

disturbance of the endocrine system, and

q adverse effects from some environmental chemicals known to act on the endocrine system have been

observed in laboratory animals.

This has provoked many national and international organisations, as well as scientific and public interest groups, toinitiate research programmes, conferences, workshops and expert panels to address and evaluate EDC-relatedissues. More...


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31-Mar-2004

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10/25

Endocrine Disruptors : 2. How do EDCs act ?




Executive Summary (Chapter 1)

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2.1 What are the mechanisms involved in EDC action ?

2.2 What are the major life stages when EDCs could act ?

2.3 What are the relationships between the EDC dose and effect ?

2.1 What are the mechanisms involved in EDC action ?

Research clearly shows that EDCs can act in a number of ways in different parts of the body. Most studies havefocused on the influence of EDCs on hormone receptors, which are the parts ofcells in target tissues that hormones

lock on to, in order to trigger an effect. EDCs, by occupying the same receptor sites in the target cells as the natura

hormone would do, can mimic the effect of a hormone or block its action.

Other ways in which EDCs can work such as disrupting hormone production, transport or breakdown have beenshown to be equally important. However, for most studies showing a link between EDC exposure and harmful effect

the mechanisms of ED action are poorly understood.

This makes it difficult to distinguish between direct and indirect effects. So care must be taken when using the resulof laboratory studies to predict effects in wildlife populations or in humans in the real world. Knowledge of the

similarities and differences in the endocrine systems of different animal species and humans is also important when

trying to predict effects in one species from observations in another.

A combined body of evidence (epidemiological and laboratory data) will be necessary to understand the situations inwhich EDC exposure may affect endocrine systems. More...


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2.2 What are the major life stages when EDCs could act ?

Despite the lack of comprehensive information on how endocrine disrupting chemicals (EDCs) can act, there areparticular stages in animal and human lifecycles that are known to be vulnerable to endocrine disruption.

What is known at present is that:

q exposure to EDCs during the early development of the endocrine system, such as in the womb, or during

childhood, may permanently alter its function or its reactions to various signals in the body,q exposure during adulthood may not show significant effects as the body is more able to adapt,q the same exposure levels may produce different effects during different life stages or even seasons,q interactions between different parts of the endocrine system may result in effects which cannot be predicted

from existing knowledge, sometimes occurring in unexpected places in the body.

There is considerable knowledge about hormonal responses at the molecular level, but little is known about howthese molecular changes might affect health. Until such information becomes available, it will remain difficult andcontroversial to attribute harmful effects to EDCs. More


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2.3 What are the relationships between the EDC dose and effect ?

The question of how much exposure to an endocrine disrupting chemical (EDC) is necessary to produce an effect isperhaps the most controversial issue in endocrine disruption. One of the reasons for this is because EDCs often act bmimicking or counteracting the actions of hormones produced naturally by the body. These natural hormones areoften more powerful than any foreign EDCs and are present in the body at levels already influencing biologicalfunction.

Since any EDC presence is an addition to these natural hormones, it can be argued that exposure to low doses of

EDCs could have measurable additional effects on biological functions. In other words, EDCs could have no thresholdfor their activity that is, any exposure, no matter how small, might trigger some effect.

Reports of EDC effects in laboratory animals at low doses are highly controversial and the subject of intenseresearch. Scientists from different laboratories have not always been able to obtain the same results at low doses.Another issue is whether traditional testing methods are robust enough to pick up low-dose effects.

Similarly, there is controversy over the issue of synergy that is, whether simultaneous exposure to EDCs withsimilar actions might produce a greater effect than the sum of their individual activities. Again, scientists fromdifferent laboratories have not been able to obtain the same results using combinations of EDCs.

The timing of exposure is also an important factor in how the body responds to different doses - both for humans an

wildlife, with respect to effects on development, reproduction, cancer, the immune system and the nervous system.

At present no firm conclusions can be drawn about low-dose effects. Researchers are continuing to look at thispossibility. More...



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14/25

Endocrine Disruptors : 3. Do EDCs affect wildlife ?

organochlorine contaminants that can affect the endocrine balance. Even though several explanations have been

proposed, the precise cause of the changes in the alligators remains unknown. More...

3.1.4 Amphibians: Population declines in amphibians, such as frogs, have been seen in both unpolluted and pollutehabitats worldwide. Currently, there is not enough information to know whether EDCs are the cause. More...

3.1.5 Fish: There is extensive evidence that chemicals found in the waste outflows from pulp and paper mills andsewage treatment plants can affect reproduction and development in fish. A variety of endocrine changes areinvolved, but it is not yet fully clear which chemicals are responsible for the changes or how they work. More...

3.1.6 Invertebrates (animals without backbones) : Exposure to tributyltin (TBT), a chemical used in antifouling

paints, provides the clearest example in invertebrates of an endocrine effect caused by an environmentalcontaminant. The females of certain marine organisms, such as snails, slugs, whelks and periwinkles, develop malesex organs when exposed to TBT. This has resulted in worldwide declines in their populations. This masculinisationeffect is probably due to increases in the levels of male hormones in the females caused by TBT. More...


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3.2 How reliable is the evidence in wildlife ?

It has been suggested that wildlife studies provide early warnings about possible harmful effects on humans of

exposure to endocrine disrupting chemicals (EDCs). But because there is such a variety of species and only a few

have been studied, it is important not to jump to conclusions about EDCs. In addition, studies on the potential effectof EDCs on wildlife have mainly concentrated on individuals, rather than whole populations or communities of

animals.

The way in which disturbances in sexual and reproductive functions, and impaired offspring survival, affect wholepopulations is difficult to quantify. Overall, the current scientific knowledge provides evidence that some

abnormalities seen in wildlife are caused by chemicals that function as EDCs. However, in most cases, the evidence a causal link between the abnormalities and exposure to particular chemicals is weak, and most effects have beenobserved in areas where chemical contamination is high. More...


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Endocrine Disruptors : 4. Do EDCs affect human health ?







4.1 What are the possible reproductive effects of EDCs in humans ?

4.2 What are other possible effects of EDCs ?

4.3 Do EDCs cause cancer in humans ?

4.4 What other factors must be considered regarding human health ?

At the moment there is no firm evidence that environmental EDCs cause health problems at low levels of exposure.

However, the fact that high levels of chemicals can impair human health through interferences with the endocrine

system, raises concerns about the possible harmful effects of EDCs. Increases in the occurrence of certain diseases

affecting the reproductive system in men and women have also raised the question of whether this could be due toexposure to EDCs. The difficulty in finding conclusive evidence on what is happening globally is compounded whenresearchers try to compare and integrate data about trends in human health from different sources collected at

different times, and often using different methods under varying conditions.

Another major problem is the lack of information on EDC exposure during critical periods of early human

development, which influence the way the body functions in later life. What is more, the amounts ofhormones we

naturally produce and the strength of their effects in our bodies are generally greater than those of foreignchemicals. However, overall, the biological plausibility of possible damage to certain human functions (particularlyreproductive and developing systems) from exposure to EDCs seems strong when viewed against the background oknown influences of endogenous and exogenous hormones on many of these processes. Therefore, despite thedifficulties and uncertainties, concern remains about the possible role of exposure to EDCs in adverse health effects

humans. The examples in 4.1. illustrate these concerns. More



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4.1 What are the possible reproductive effects of EDCs in humans ?

4.1.1 Reproductive effects:

q Sperm quality: A number of studies report a decline (since the 1930s) in sperm quality i.e. sperm count,proportion of normal sperm, semen volume in several countries, which might be expected to affect fertilityBut not everyone agrees with these results. Several surveys refute this downward trend in human spermquality. Even if there is not a worldwide decline in sperm quality, there are clearly variations in sperm qualitboth within and between countries. From what is known about testis development and function, it is plausib

that endocrine-active chemicals could affect sperm quality. But so far, no research has studied therelationship between exposure to endocrine disrupting chemicals and sperm quality. More...

q Fertility: Some human and experimental animal studies have shown that occupational or environmentalexposure to high levels of certain chemicals, such as pesticides and PCBs, can impair fertility and increase t

rate of miscarriages, but any relationship to endocrine disruption remains speculative.q Sex ratio: In a number of regions and countries, fewer boys than girls are being born. There is evidence tha

unidentified external influences are associated with such changes, but it is not known whether endocrinedisruptors are involved.

q Abnormalities of male sex organs: Increased numbers of birth defects in male sex organs have beenreported. The abnormalities are cryptorchidism, a condition in which the testes remain inside the abdominal

area instead of dropping down, and hypospadias, which is a malformation where the opening is on the

underside of the penis instead of the end. The possible role of EDC exposure in these human malformations

has not been investigated. However, experimental animal studies clearly show that a number of EDCs can

disrupt development of the male reproductive system.

4.1.2 Endometriosis: This is a disease affecting women where uterine tissue appears in parts of the abdomen othe

than the uterus, causing pain and infertility. The disease is made worse by oestrogens. Some reports have linkeddevelopment of endometriosis in women to exposure to EDCs, such as dioxins. However, these findings aredebatable. More...

4.1.3 Precocious puberty: Some studies have raised concerns about the possible influence of EDCs on the timing puberty, or the process of sexual maturation. There is evidence from population studies that the age at whichpuberty normally occurs is becoming younger, but the reasons for this and the role of other factors, such as nutritioneed to be clarified. More...



4.2 What are other possible effects of EDCs ?

4.2.1 Nervous system function: Information from human and experimental animal studies clearly shows thatexposure to certain endocrine disrupting chemicals (EDCs), such as PCBs particularly before birth can harm the

development of the nervous system, neuroendocrine function, and behaviour. Some of these effects appear to resulfrom alterations in thyroid function or in the activity of the chemicals which carry messages between nerve cells. In

the majority of cases, however, it has not been demonstrated that these effects are due to endocrine disruption.Similar effects can also result from exposure to chemicals that influence nervous system development, but have noknown action on the endocrine system. More...

4.2.2 Immune Function: The immune system is involved in fighting infections and in allergic reactions. Exposure tenvironmental chemicals including certain EDCs, such as DES, a powerful synthetic oestrogen, or PCBs and dioxin

has been shown to alter human and animal immunity. But it is not clear whether this occurs via endocrinedisruption. More...

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4.3 Do EDCs cause cancer in humans ?

4.3.1 Cancer: The occurrence of certain cancers at hormonally sensitive sites in the body has been increasing overtime in many industrialised countries. Although some of the apparent increases may be due to improvement in ourability to detect cancer, it does not explain all of the increases. This has led to suggestions that the generalpopulations widespread exposure to endocrine disrupting chemicals (EDCs) could be damaging human health. One

argument is that the increases are roughly linked in time with the increased use and release of industrial chemicalsinto the environment. More...

4.3.2 Breast Cancer: Numerous studies have examined whether environmental EDCs, particularly organochlorinecontaminants such as DDT and PCBs, may increase breast cancer risk in women, but the current scientific evidence

does not support such a conclusion. All the studies have the same weakness in that they measured current EDClevels in women both with and without breast cancer, but they had no data on exposure during other potentiallyimportant periods in their lives, such as while they were in the womb, or during childhood and adolescence. Duringthe mid-twentieth century, organochlorine contaminants were more widespread, making the absence of this early

exposure information a major problem. More...

4.3.3 Endometrial Cancer: There are very few studies on endometrial cancer, which is cancer of the lining of thewomb, and exposure to EDCs. Although exposure to oestrogen is known to increase the risk of this cancer, the

number of women developing endometrial cancer is not increasing. The limited experimental and human studiesavailable on this subject fail to draw a link between EDCs and endometrial cancer.More...

4.3.4 Testicular Cancer: Cancer of the testis is the most common cancer in young men. A number of countries havreported increases of this form of cancer, but with considerably varying rates. The rate started rising around 1910 inthe Nordic countries even earlier in England and Wales which means it cannot be attributed solely to chemicalsintroduced in the mid- or late twentieth century. Some evidence suggests that male sex organ abnormalities (see4.1.) may be linked to testicular cancer, both because they have a similar geographical distribution and because themay have a common origin if sex hormone levels are disturbed during early development. However, no studies have

examined the relationship between testicular cancer and EDC exposure during critical periods of development.More...

4.3.5 Prostate Cancer: Prostate cancer occurs mainly in older men and is the most common male cancer. Much ofthe increase in prostate cancer is due to improved diagnosis. It is known that male sex hormones cause growth ofprostate cancers and oestrogens reduce the size of prostate cancers. Exposure to certain pesticides and

organochlorines has been linked to increases in the incidence of prostate cancer in a few limited studies. Otherstudies have found no association between EDC exposure and this form of cancer. More...

4.3.6 Thyroid Cancer: : It is known from experimental animal studies that some chemicals, such as certainpesticides, can disturb the part of the brain that controls thyroid hormone release, or can increase the destructionrate ofthyroid hormones in the liver, thereby causing thyroid tumours. Yet so far no relationship between exposure

to EDCs and thyroid cancer in humans has been shown. More...


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4.4 What other factors must be considered regarding human health ?

Three kinds of evidence have to be considered in reaching tentative conclusions about EDCs and human health at thpoint in time:

q know ledge about hormones and the endocrine system: overall, the biological plausibility of possibledamage to certain human functions from exposure to EDCs seems strong, particularly for reproduction and

development;q evidence from other species:adverse effects found in wildlife and laboratory animals exposed to EDCs

support concerns about possible similar effects in humans;q evidence from humans: changes in certain human health trends are also worrying enough to make this

area a high research priority.

Both the possible roles of EDCs and non-EDC mechanisms need to be explored. Above all, the links between humanexposure to low environmental levels of EDCs and health effects needs to be investigated. More...





31-Mar-2004

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Endocrine Disruptors : 5. What are potential sources of EDC exposure ?



The answer to Question 5 is taken from: IPCS " Global Assessment of Endocrine disruptors"




Lack of scientifically sound data about the frequency, length and levels ofexposure to endocrine disrupting chemica

(EDCs) is the weak link in the argument that they have harmful effects on human and animal health. Most of the

information on EDC exposure has focused on the presence of persistent organic pollutants, such as PCBs, dioxins,

DDT and other chlorine-containing pesticides, in Europe and North America. Exposures to other non-persistent EDCshave not been investigated in any depth.

Another shortcoming is the lack of information on exposure during critical periods of human or animal development.Moreover, the available information relates mostly to EDCs present in the environment such as in the air, food andwater rather than to levels in blood and tissues in the body. Limited exceptions are human breast milk and fattissuesamples, which have been screened for potential EDCs, such as organochlorines.

Generally, exposure to potential EDCs occurs through contaminated food and groundwater, gas emissions fromindustrial sources and the burning of waste, and contaminants in consumer products.

Despite a heavy investment of money, time and effort worldwide, information comparing human and wildlife EDCexposures in different countries is still sorely needed. Such information, obtained through field studies on wildlife anstudies in human populations - epidemiological studies - on diseases or other observations like sperm quality or

outcomes of pregnancy, is essential to establish causal relationships between exposure and response. Exposureinformation is also essential to produce a credible risk assessment of this problem. More





31-Mar-2004

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20/25

Endocrine Disruptors : 7. Conclusions

ome > Studies > Endocrine > Level 2 > Conclusions


Previous Question Level 1 Questions

6. Conclusions

6.1 What conclusions can be drawn concerning EDC effects in humans ?

6.2 What conclusions can be drawn concerning EDC effects in wildlife ?

6.3 What are the future research needs identified by the IPCS report ?

Studies carried out to date have focused on North America and Europe, so conclusions about endocrine disruptingchemical (EDC) effects worldwide cannot be drawn, especially not for developing countries where very littleinformation is available. More...



6.1 What conclusions can be drawn concerning EDC effects in humans ?

Although it is known from laboratory and wildlife studies that certain environmental chemicals can disrupt normalendocrine function, evidence suggesting that human health has been affected remains weak. There are some signsthat humans are vulnerable to endocrine disrupting chemicals (EDCs) at high levels ofexposure, but effects from

long-term and low-level EDC exposure have yet to be proven. This statement is not meant to downplay the potentiaeffects of EDCs; rather, it highlights the need for more rigorous studies, especially those examining the possibleeffects from exposure to EDCs at sensitive stages in early life. More...



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21/25

Endocrine Disruptors : 7. Conclusions

6.2 What conclusions can be drawn concerning EDC effects in wildlife ?

Evidence about the effects of endocrine disrupting chemicals (EDCs) on wildlife is more extensive than for humans,showing that EDCs have, indeed, harmed wildlife. Of course, the ability to study wildlife species both in the laboratoand in the field has been helpful.

Many of the studies showing adverse effects in wildlife have been undertaken in areas where pollution was reported

to be high, particularly in aquatic ecosystems, where persistent environmental chemicals accumulate.

A big challenge in this area is to broaden the research to cover more thoroughly more species in the wild, and todevelop a better understanding of their biology and their different endocrine systems. This way, more can be learne

about the many species that could potentially be affected by EDCs. More...


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6.3 What are the future research needs identified by the IPCS report ?

It is clear that too little is known about the link between exposures to potential endocrine disrupting chemicals(EDCs) and their effects on health both humans and wildlife. Nevertheless, some progress has been made inidentifying potential EDCs and studying the ways in which they work by using laboratory animals. Research hasmainly focused on chemicals that persist in the environment and accumulate in living organisms, but less persistentchemicals also require attention. International collaboration is needed in some broad research areas, such as in:

q understanding how endocrine disruption interferes with normal biological processes,q clarify the relationships between effects observed in the laboratory and those observed in the wildq developing improved methods for detecting EDCs,q increasing monitoring of organisms in the wild and monitoring of potentially relevant trends in human healthq identifying EDCs most likely to have substantial effects in populations at low environmental concentrations,q identifying any hot spots of high exposure to EDCs,

q investigating life stages or species that might be particularly vulnerable to EDCs, andq assembling global information on EDCs into usable and shared databases.

This research is a priority because of the endocrine systems key role in many aspects of normal human - and animadevelopment and function. More information about how EDC exposure may impair or damage this vital system istherefore paramount. More...


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30-Mar-2004

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GreenFacts : Sources for the Endocrine Disruptors study

ome > Studies > Endocrine > About this study


GreenFacts Copyright Policy

About this Endocrine Disruptors Study

1. Sources for this Study

2. Current Status

3. Study Publication History

. Sources for this Study

Most of the texts on Level 3 are sourced from the Executive Summary (Chapter 1)

of the "Global Assessment of the state-of-the-science of Endocrine Disruptors"

a leading scientific report produced by a large international panel of scientists and published in 2002 by the IPCS

(International Programme on Chemical Safety).

More on the Source and Copyright

2. Current Status

Approved for publication by the GreenFacts Scientific Board.

3. Study Publication History

The GreenFacts publication process is designed to ensure as high a degree of objectivity as possible.

First draft

The first draft of this Endocrine Disruptors study was produced by Dr Sue Barlow on 20 June 2003 and posted on-linin July 2003.

Preliminary review

The draft was revised and commented by experts from environmental organizations and industry in summer 2003.

Peer review

ttp://www.greenfacts.org/en

Documents

Endocrines Dis Rup Tors Green Facts