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Children and the unborn child

7. Summary, conclusions and recommendations

Concern has been raised that infants and children are at higher risk than adults from exposure to environmental chemicals. In particular, this important discussion has focused on the potential higher exposure of infants and children and increased vulnerability to the detrimental effects of chemicals. In 1998, the Danish government initiated a cross-ministerial overview concerning "protection of children and pregnant women against dangerous substances" and a conference was held in October 1998 in order to pay more attention to this topic and to discuss and identify possible needs for further development. The overall impression from the discussions at the conference was that children and pregnant women should generally be recognised as special risk groups with respect to effects from exposure to chemical substances. As a consequence, the present project was initiated by the Danish EPA.

7.1 Summary

7.1.1 Aim of the project

The purpose of the project was to elaborate a detailed review and update the knowledge on the exposure and vulnerability of humans to chemical substances during the embryonic, foetal and postnatal periods (up to the age of about 18 years). The report is intended to form the scientific basis for future regulatory work of the Danish EPA in the protection of children and the unborn child to environmental chemical substances. Consequently, the report primarily focuses on chemical substances and regulatory aspects for which the Danish EPA has the responsibility. However, other chemical substances, such as drugs, have been included when they provide illustrative examples within the context of the report.

7.1.2 Biological susceptibility

Age-related differences in organ susceptibility are a function of toxicokinetic and toxicodynamic parameters, including genetic, physiological, and metabolic factors, mechanism of action of the substance, and dose-effect and dose-response relationships. The toxicokinetic aspects cover absorption, distribution, metabolic conversion and excretion of a given substance. The toxicodynamic aspects cover parameters such as organ sensitivity and cytoprotective mechanisms, which determine the extent of any effect or response due to the presence of the substance at the site of toxicity.

Chemical substances that pass maternal membranes are likely also to pass the placental barrier. As the placenta is permeable to chemical substances, almost all xenobiotics enter the foetal circulation. Therefore, the foetus is generally not protected against xenobiotics that circulate in the maternal blood.
During the preimplantation period, the conceptus is generally considered refractory to exogenous insults in terms of induction of classical malformations, but induction of embryonic death and/or latent developmental defects may occur (e.g., from exposure to DDT or nicotine). The chemically induced classical malformations and/or syndromes are mainly induced in early pregnancy during the period of organogenesis. Well-known examples of such teratogens are cytostatics, thalidomide, and diethylstilboestrol.
Exposure to chemicals (e.g., ethanol and methylmercury) during the subsequent foetal period (after 8 weeks of pregnancy) is not considered to result in major malformations, but susceptibility to substances affecting specific receptors and molecular targets still under development may lead to pronounced effects on a number of developmental processes. Informations concerning induction of such changes in humans in the foetal period are relatively scarce, but based on studies in experimental animals, it appears that this period may be even more sensitive than the embryonic stage to some growth and functional disturbances. However, in humans it may be difficult to interpret whether such damages are caused by pre- or post-natal events.
A number of findings reported over the last decade suggest that exposure to environmental factors in early life can increase the risk of disease later in life. To explain such findings, the concept of physiologic programming or imprinting in early life has emerged. Interference with such genetic programming has been demonstrated in a variety of test systems and reflects the action of a factor during a sensitive period or window of development to exert organisational effects that persist throughout life.

peri- and post-natal periods

The peri- and post-natal periods appear to be vulnerable periods, especially with respect to the physiological development of the central nervous system. There is human evidence that exposure to toxic substances (e.g., methyl mercury, TCDD) during the perinatal period of development may induce persistent functional/behavioural effects that become manifest shortly after birth or later in life although not morphologically apparent. After birth, the physiological development of the nervous, immune, and endocrine/reproductive systems continue to develop until adolescence. Therefore, the post-natal period should also be considered vulnerable. During the breastfeeding, the infant is exposed to chemical substances through human milk. As the functionalities of many organs are still immature, the new-born may be particular susceptible to xenobiotics.

Toxicokinetics and toxicodynamics

Age-dependent differences in susceptibility to a chemical substance may be due to differences in either toxicokinetics or toxicodynamics, or both. Age-related differences in toxicokinetics/toxicodynamics occur in both experimental animals and humans. Except for a few specific substances, not very much is known about whether and why the response to a compound may differ between age-groups.

toxicodynamics

In general, it appears that effects of xenobiotics on organs or end-points may be similar in children and adults e.g., liver necrosis observed in adults will also be observed in children. As regards toxicodynamics, age-dependent differences are primarily related to the specific and unique effects that chemical substances may have on the development of the embryo, foetus and child in that the physiological development of the nervous, immune, and endocrine/ reproductive systems continue to develop until adolescence. Furthermore, receptors and other molecular targets for various xenobiotics are continuously developing during the embryonic, foetal and infant periods. This may cause age-dependent differences in the outcome of receptor-xenobiotic interactions and even result in opposite effects of xenobiotics in infants and adults.

toxicokinetics

During pregnancy, many physiological changes occur in the maternal organism as a consequence of, and in order to support, the rapid growth of the foetus and reproductive tissues. These changes may in different ways influence the intake, absorption, distribution, metabolism and elimination of xenobiotics. The human foetus and the placenta possess metabolic capacity, but the contribution of these metabolising entities to the total kinetics is probably minimal.
In early infancy, the organs are still rather immature and various maturation processes are taking place. The complexity of all these factors makes it difficult to predict the net effect on absorption, distribution and elimination of chemical substances. However, the maturation of the gastrointestinal system, liver and kidneys has generally taken place within 6-12 months after birth. By late infancy, most processes related to metabolic activity and excretion are probably comparable to that of adults for most compounds. Because of the immature function of the organs, neonates and young infants may have lower biotransformation and elimination capacities. This may render these individuals less able to detoxify and excrete xenobiotics and thereby more vulnerable to toxicants. On the other hand, if toxicity is caused by toxic intermediates produced via biotransformation, young infants may be less sensitive.

In the subsequent late infancy and childhood, metabolism and excretion of xenobiotics may be equal to or even higher than in adults due to the higher basal metabolic rate and relative liver size. It is difficult to generalise about age-dependent deficiencies in the metabolism of xenobiotics because the various enzyme systems mature at different time points. The age at which metabolism is similar to the adult value may be different for each compound.

7.1.3 Exposure

Infants and children may be exposed to certain chemicals in the environment to a larger extent than adults as they, on a body weight basis, breathe more air, drink more water, and eat more food than adults. In addition, their behavioural patterns, such as being naturally curious, playing close to the ground, and putting their hands and objects into their mouth, can increase their exposure to chemicals in the environment. Children also have more years of life ahead of them than adults, so they have more time to develop those chronic diseases that take several decades to appear, and which may be triggered by early environmental exposure. Diseases with long latency periods include some forms of cancers such as mesothelioma from asbestos, skin cancer from sunlight, and leukaemia from benzene. Also, substances which accumulate in the organism may be of concern in this respect.

Unborn child

Most chemical substances entering the bloodstream of the pregnant mother will be distributed to the embryo/foetus. The exposure of the unborn child will thus be a reflection of the exposure pattern of the mother. Persistent substances accumulated in tissues and organs of the mother (from previous exposures) may be redistributed to the unborn child (e.g., lead deposited in the bones of the mother).

Infants and children human milk

The infant is exposed to chemical substances through breast-feeding. Persistent organohalogenated substances (e.g., PCBs, dioxins and brominated flame retardants) accumulate in adipose tissue and are excreted into human milk at levels providing a comparably much higher intake in breast-fed infant than adults.

drinking water

Contamination of drinking water due to pollution by xenobiotics (e.g., pesticides and other industrial chemicals) as well as high levels of natural constituents (e.g., fluoride, copper and nitrate) constitute a potential health risk for all individuals. Infants and children are, however, at a higher risk since they, on a bodyweight basis, consume up to 5 times more water than adults.

diet and beverages

Infants and young children have a dietary pattern different from that of adults as they have a higher food intake per kg body weight and often also have special food preferences and needs. On a body weight basis, the average consumption of the main food groups (fruit, vegetables, bread, cereals, meat, fish, eggs) has been reported to be about 2-2.5 times higher in young children (aged 1½ to 4½) than in adults. For dairy products (excluding milk) and confectionery (including sugar), consumption up to 5 times the corresponding adult figures have been reported. For milk and beverages, the consumption by young children was reported to be up to 9 times and 16 times, respectively, higher than by adults.

air

Children inhale a relatively larger volume of air compared to adults and at the same time they often have a higher activity level (e.g., during playing) thus increasing their respiration rate. In some situations, children also have a higher exposure to e.g. vehicle exhaust as they, due to their height, inhale the air at a level closer to the vehicle emissions.

exposure via dermal contact

The use of cosmetics by different age-groups, including infants and children, has increased during recent years and consequently, exposure to chemical substances via cosmetics is increasing. Examples of products which are increasingly used by infants and children include child care products, bath and shower preparations, suncare products, wet tissues, hair care products (containing colours and bleaches), and special cosmetics meant for children (e.g., face paints). Cosmetics and child care products may be used repetitively and on a relatively large surface area of the skin. If skin irritation or skin damage is present, the absorption of chemicals from these products may be increased.

behavioural differences

Infants and children are by nature curious and continuously examine their environment. Especially oral exposure to chemical substances due to hand-to-mouth activities (e.g., ingestion of contaminants from soil and dust) and object-to-mouth activities (e.g., ingestion of phthalates migrating from toys, and mercapto benzothiazole migrating from soothers and teats made of natural rubber) are specific to infants and young children and thus present a risk of higher exposures to chemical substances for this age group compared to adults. Accidental exposures to a number of different chemical substances and products, primarily household chemicals, organic solvents, drugs, irritating gases, asphyxiants in fumes, and poisonous animals, plants and fungi are also contributing to a higher exposure in children.

7.1.4 Testing methodology

Well-planned and documented epidemiological studies have a clear advantage over studies in experimental animals in providing the most relevant information on health effects in humans, thus avoiding extrapolation from experimental animals. However, epidemiological studies have limitations too, particularly in determining exposure of chemical substances at environmental levels. In addition, epidemiological data can only be obtained after the substance in question has been introduced into the society.
Owing to the lack of adequate epidemiological data for most chemical substances, toxicological studies in animal species play an important role in hazard identification and risk assessment. For new chemical substances, this is the only way to obtain in vivo toxicity data.

Many different experimental methods for investigating toxic effects of chemical substances during the prenatal and postnatal period are in use. Several tests are standardised and guidelines have been issued by various governmental agencies and international organisations. The standardised reproductive toxicity tests can provide information on a number of developmental effects, such as malformations, growth retardation, foetal and postnatal death, fertility, and functional effects on the central nervous system. In a revised proposal for the two-generation reproductive toxicity study (OECD TG 416), assessment of effects on sperm quality and oestrous cyclicity in offspring have been added. It should be noted, however, that the majority of marketed chemical substances have not been tested according to the standardised reproductive toxicity tests and thus, a number of the developmental effects mentioned above have not been examined. In particular, investigations on effects on the developing brain are scarce. The OECD Guideline for Developmental Neurotoxicity Study is still only a draft and therefore not included in the presently used testing strategies.

Repeated dose toxicity testing in adult animals provide information on the potential for systemic toxicity by investigations of growth, clinical symptoms, haematology, biochemistry, organ weights, pathology and histopathology of organs. The investigations of systemic effects in the reproductive toxicity tests are not as comprehensive as the repeated dose toxicity studies in adults. In order to have a sufficient background to determine the sensitivity of the developmental period compared to adulthood there is a need for studies where end-points are investigated similarly for both age groups. Ideally, this would require a two-generation study incorporating developmental neurotoxicity end-points and supplemented with similar investigations of systemic effects in offspring as in repeated dose toxicity studies.

For drugs, there is at present no mandatory requirement in the EU for pharmaceutical companies to investigate new medicinal products in children; however, industry is encouraged to investigate the safety and efficacy of a product in children, if it is likely to be of therapeutic benefit to this age group. Guidelines on Clinical Investigation of Medicinal Products in Children have been issued by the European Committee for Proprietary Medicinal Products (CPMP); the guidelines state the scientific data required before medicinal product testing in children and points at juvenile animal safety studies when previous animal data and human safety data are insufficient.

7.1.5 Specific substances, examples of exposure and effects

For a number of chemical substances, including drugs, differences in biological susceptibility and/or differences in exposure between children and adults have been reported in the literature. The examples mentioned include alcohol, tobacco-smoke, ambient air pollution, pesticides, drugs, PCBs, dioxins, polybrominated flame retardants, phthalates, lead, mercury, copper, boric acid, and nitrate and nitrite. It should be stressed that these examples are illustrative cases and therefore by no means are an exhaustive overview covering all cases and aspects.

7.1.6 Regulations

In order to assure the best possible protection against adverse effects resulting from exposure to chemical substances, several regulations within different areas have been issued. The most relevant Danish regulations on chemical substances which include the protection of children and pregnant women and their unborn child from exposure to environmental chemical substances have been summarised.

It should be noticed that the regulations of chemical substances are based on the existing knowledge regarding adverse effects and risks related to the use of the substances. For the great majority of chemical substances in use, very little - if any - knowledge exists regarding the relevant exposure scenarios and/or vulnerability of children, including the unborn child.

In 1998, the Danish Government initiated a cross-ministerial overview concerning the administrative measures for protecting children and pregnant women. From this overview, it was concluded that in specific areas an increased effort should be made to increase the protection of children and pregnant women. Several future initiatives in different ministerial sectors were proposed.

Within the field of environmental factors and regulations of chemical substances, it was concluded that more attention should be paid to protection of children and/or pregnant women in relation to:

	the use of chemical substances in cosmetics and toys
	risk assessment procedures in the EU
	risk assessment procedures in relation to the national derivation of limit values for chemical substances in air, soil and water
	the procedures for approval of pesticides (especially pesticides for domestic use) and for risk assessment of food additives and food contaminants.

7.2 Conclusions

Much of the current knowledge on adverse health effects from exposure to environmental chemical substances comes from studies on adults. Similarly, many of the present regulations are based on data that do not specifically include risks to children. However, children have different physical, biological and social environments and these factors may all contribute to differences observed between children and adults in response to chemical substances. Children also have more years of life ahead of them than adults and therefore have more time to develop those chronic diseases that take several decades to appear, and which may be triggered by early environmental exposure. This leads to a particular concern for children in relation to exposure to some carcinogenic substances and for substances that accumulate in the organism.

7.2.1 Biological susceptibility

In a number of cases, the unborn child and the infant have been reported more vulnerable to toxic effects than adults. Periods of rapid growth and development render them susceptible to specific toxic endpoints. In addition to such toxicodynamic factors, differences in toxicokinetics such as absorption, elimination and metabolic capacity may be contributing factors to an increased susceptibility during these periods.

Susceptible periods in human development

Developmental deficits are predominantly induced during the pre- and peri-natal periods, which should be considered the most vulnerable periods. The post-natal period appears to be vulnerable with respect to the physiological development of the nervous, immune, and endocrine/reproductive systems as these systems continue to develop until adolescence. There is now increasing awareness that insults to developmental processes, which may not be morphologically apparent, may none the less cause functional disturbances later in life. Based on the current experimental database, concern in this respect has mostly been related to the risk of behavioural and reproductive disturbances.

The present knowledge, however, does not allow an overall generalisation concerning increased susceptibility of foetuses/infants compared to adults, as only a limited number of studies exist in which the susceptibility in foetuses/infants have been systematically compared to adults. Several examples, however, show that serious effects can be found in foetuses/infants at dose levels not causing effects in adults. For foetuses, it is generally recognised that marked toxic effects in the pregnant animal normally also leads to effects in the foetuses, i.e. it is rarely seen that the susceptibility of the foetus is lower than that of adults.

Toxicokinetics

Regarding toxicokinetic differences between children and adults, examples have shown that during the developmental and maturational periods, the susceptibility to chemical exposure in children may be higher, equal or even lower than in adults. Children do not seem to represent a special group from a toxicokinetic viewpoint regarding variability among children as the toxicokinetic variability among children generally appears to be of a similar magnitude as the variability among adults.

Toxicodynamics

Age-dependent differences in toxicodynamics are primarily related to the specific and unique effects that chemical substances may have on the development of the embryo, foetus, and child. However, there are insufficient data to evaluate the toxicodynamic variability among children as well as the differences between children, including the unborn child, and adults.

Overall, age-related differences in the biological susceptibility of a specific chemical substance can only be assessed if adequate data regarding adverse health effects during the different periods of life (foetal, neonatal, childhood, adolescence, and adulthood) are available.

7.2.2 Exposure

Under certain circumstances, infants and children are exposed to chemical substances to a greater extent than adults because of their higher intakes (on a body weight basis) of diet and beverages, drinking water, and air and also due to their behavioural patterns. Infants and children are curious by nature, have different activity patterns (e.g., hand/object-to-mouth activities, playing close to the ground), and show differences in food preferences (e.g., drink much more milk and soft drinks). Furthermore, substantial dermal exposure of infants and children may occur from the use of cosmetics and child care products.
The unborn child may have special exposures resulting from exposures of the pregnant woman e.g., from her working environment and during her leisure activities.

For most chemical substances, only limited data are available concerning exposure of children as well as of adults. In the risk assessment process it is thus difficult specifically to assess differences in exposures of children compared to adults.

7.3 Recommendations

The regulations of chemical substances are generally based on the present knowledge regarding adverse health effects and risks related to the use of the substances. However, the available data on a specific chemical substance are seldom sufficient to evaluate whether children or the unborn child should be considered more vulnerable than adults. Concerning specific end-points such as fertility and teratogenicity, data exist only for 20 to 30% of the 2500 high production volume chemicals, and for thousands of chemicals produced in smaller quantities, this percentage is expected to be considerably lower. Furthermore, for most chemical substances, limited data are available concerning exposure of children as well as of adults.

From a regulatory point of view, different approaches can be applied in order to protect children, including the unborn child, from adverse health effects resulting from exposure to environmental chemical substances. One regulatory approach is to improve the risk assessment of chemical substances by including requirement of data specifically relevant for the protection of children, including the unborn child. Another approach is to pay more attention on children and pregnant women in the risk management process.
Also the use of the precautionary principle should be emphasised. Thus, regulatory measures should be undertaken in cases where potentially adverse health effects are of concern but the scientific evidence is not available due to lack of data.

7.3.1 Risk assessement

In relation to human health, a risk assessment consists of an effect assessment (hazard identification, and dose/concentration-response and -effects assessment), an exposure assessment (estimation of the concentrations/doses to which human populations are or may be exposed), and a risk characterisation (estimation of the incidence and severity of the adverse effects likely to occur in a human population due to actual or predicted exposure to a substance). In most cases, the risk assessment is performed for a specific substance and only seldom data are available to account for interactions due to simultaneously exposure to other substances.
For the great majority of chemical substances used, limited data - if any - are available on adverse health effects during the different periods of life as well as on exposures of children, including the unborn child. Increased vulnerability of children, including the unborn child, has been reported for a wide range of different substances, but a clear answer on such differences in vulnerability can only be given for a specific substance if a rather extended data set is available. Therefore, the possibility of increased vulnerability of children, including the unborn child, should always be kept in mind in the risk assessment of chemical substances. Greatest concern, however, exists for the unborn child and neonate (up to the age of 3 to 6 months) because they are in a period of rapid growth and development and have a lower capacity to eliminate toxic substances.

Recommendation

In risk assessment, the exposure assessment is as important as the effect assessment. However, only very little is known concerning specific infant/child exposures. Especially in relation to the increasing use of chemical products marketed for children (cosmetics, child care products, and toys) data regarding exposure are not available.
In the risk assessment of chemical substances in products and foods intended for children (e.g., in cosmetics, toys, child care products, food additives in preferred foods, and pesticide residues in processed baby foods and infant formulae), it is strongly recommended to perform child-specific risk assessments.
In the risk assessment of chemical substances in other use categories than the above-mentioned, it is recommended specifically to focus on children, including the unborn child, if a potential exposure to a given substance may occur to these age-groups.
As children, including the unborn child, are simultaneously exposed to several chemical substances, the possibility of combination effects should also be considered.
Furthermore, it is recommended that the risk assessment should be performed by experts on a case-by-case basis for each substance and for each exposure scenario.

7.3.2 Testing of chemical substances

One regulatory approach in relation to the risk assessment of chemical substances is to require a more extensive documentation of health effects as well as of exposures specifically regarding children, including the unborn child. Such documentation could be obtained from epidemiological studies as well as from studies in experimental animals. Different testing strategies have been issued for various regulatory areas.

For new high production volume chemical substances (marketed after 18 September 1981 and produced in amounts above 1000 tonnes/year), food additives, pesticides, and drugs, testing of adverse health effects is required by the competent authorities to an extent which is generally considered sufficient to assure the safety in use, including the intentional use to children. However, the majority of existing chemical substances (marketed before 18 September 1981), including contaminants in foods, have generally not yet been tested adequately to evaluate the risk of inducing adverse effects in children.

Regarding the unborn child and neonate, the standardised reproductive toxicity tests provide information on a number of developmental effects and in the revised proposal for the two-generation reproductive toxicity study (OECD TG 416), assessment of effects on sperm quality and oestrous cyclicity in offspring have been added. However, investigations on effects on the developing brain are not included in the presently used testing strategies because the OECD Guideline for developmental neurotoxicity is at present only a draft. In addition, the investigations of systemic effects in the reproductive toxicity tests are not as comprehensive as in the repeated dose toxicity studies in adults. Also, investigations of endocrine disruption are not included in guidelines at present.
Ideally, a comprehensive testing of end-points specifically relevant for protection of children, including the unborn child, would require a two-generation study (OECD TG 416) incorporating developmental neurotoxicity end-points and supplemented with similar investigations of systemic effects in the offspring as in the repeated dose toxicity studies in adults as well as investigations of endocrine disruption.

Recommendation

For chemical substances, it is specifically recommended to consider whether there is a need for additional testing of reproductive toxicity. The evaluation should be performed on a case-by-case basis for each substance based on the available data on adverse health effects, on potential exposure of children, including the unborn child, as well as on other properties of the substance. If concern for children and/or the unborn child arises, a comprehensive testing of end-points specifically relevant for protection of children, including the unborn child, should be required. The relevant study is a two-generation study (OECD TG 416) incorporating developmental neurotoxicity end-points and supplemented with similar investigations of systemic effects in the offspring as in the repeated dose toxicity studies in adults as well as investigations of endocrine disruption. This recommendation clearly implies that updated and new testing guidelines should be incorporated into the presently used testing strategies concurrently with their endorsement.

7.3.3 Risk management

For many chemical substances, a risk assessment specifically endeavoured to children, including the unborn child, cannot be performed due to lack of data on health effects as well as exposure. In such cases, the risk management process should more specifically focus on the protection of children and pregnant women. Furthermore, the need for regulatory action has to be balanced against the need for a comprehensive documentation, which would require extensive resources and time. Different regulatory approaches can be applied.

Additional safety measures

In the establishment of health based limit values for chemical substances in ambient air, soil, and drinking water, three safety factors (uncertainty factors) are used in the derivation of the tolerable daily concentration or intake to account for interspecies variation in susceptibility, differences in intraspecies susceptibility, and for the quality and relevance of the available data.
The safety factor for differences in intraspecies susceptibility is used to account for the general variability of the population including susceptible subgroups such as children, pregnant women and their unborn child, and elderly or sick people; a default value of 10 is generally used. The possibility of increased susceptibility of children, including the unborn child, should always be kept in mind in the risk assessment of chemical substances. Greatest concern, however, exists for the unborn child and neonate (up to the age of 3 to 6 months) because they are in a period of rapid growth and development and have a lower capacity to eliminate toxic substances.
The safety factor for quality and relevance of the available data is used to account for all other relevant aspects than the inter- and intraindividual variability. Examples include testing on only a few animals or at just one or a limited number of doses/concentrations, the exposure route is not relevant for the human exposure situation (injections), cases where a NOAEL cannot be established, extrapolation from a short exposure duration to lifetime-exposure, and severity of effects. Lack of the relevant data are accounted for in the magnitude for this safety factor.
Having obtained the tolerable daily concentration or intake, the health based limit value is derived by taking into account a default value for the daily exposure from the various media. For the derivation of the limit value for ambient air and drinking water, default values for exposure of an adult person is used; however, for soil exposure, a default value for exposure of children is used.

recommendation

In case that the available data are insufficient to evaluate the susceptibility of children, including the unborn child, it is strongly recommended that additional safety measures (choice of safety factors) should be considered when acceptable or tolerable daily intakes (ADIs or TDIs) or health based limit values for chemical substances in products and foods intended for children (e.g., in cosmetics, toys, child care products, food additives in preferred foods, and pesticide residues in processed baby foods and infant formulae) are established.
In the derivation of health based limit values in ambient air, soil, and drinking water, it is recommended to use default values for exposure of children for all three environmental media.

Group-evaluation

For the majority of chemical substances, very little, if any, knowledge exist regarding toxicity from pre- and perinatal exposure. Classification and risk assessment of chemical substances are based on available data. Although having different properties, the majority of chemical substances can be assigned to groups defined on the basis of their chemical structure, physico-chemical properties, biochemical effects, or other resemblance or relationship, all of which may be significant for the toxicological effects of a specific substance.

recommendation

In order to make the best possible use of the available data on chemical substances, it is recommended to use the knowledge and models concerning structure activity relationships (SAR) as a tool in risk assessment, in prioritising for further testing, and in regulation of chemical substances.

Positive or negative list

Infants and children are often exposed to a higher degree than adults to certain chemical substances e.g., in cosmetics, toys, childcare products, food additives in preferred foods, and pesticide residues in processed baby foods and infant formulae. However, for most chemical substances, limited data are available concerning exposure of children from these products as well as additional exposure from various other media (other foods, drinking water, contaminated soil). Food additives are listed in the Positive List and special regulation on food additive use in infant formulae is in force in the EU. Certain substances are considered undesired in products and foods intended for children, particularly for younger children (0 to 3 years old). An example is the EU prohibition of the use of phthalates in toys and childcare products to children at the age of 0 to 3 years. Another example is that in the EU, some specific pesticides must not be used in agricultural products intended for the production of baby foods and infant formulae.

recommendation

In order to protect children from exposure to undesirable substances, it is recommended to introduce specific lists (positive or negative) for use of chemical substances in products intended for children such as cosmetics, toys, child care products, and pesticide residues in processed baby foods and infant formulae.

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