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Special attention must be paid to children in the risk assessment of chemicals

32/2001, 08.10.2001

Children cannot be treated as "miniature adults" when it comes to assessing the risks associated with agricultural and household chemicals in plant protection products, pesticides, household cleaning products, etc. In its recommendations on pesticides and plant protection products, BgVV has, therefore, for some time now taken children as the most sensitive group of consumers in order to achieve the highest possible standards in consumer protection. This is reflected, for instance, in the maximum residue levels in foods for infants and small children pursuant to § 14 Diet Regulations.

When estimating the risks for children, it must be borne in mind that the capacity of the child's organism to excrete substances changes as it grows older. More attention must be paid to the fact that the child's organism is constantly developing from birth up to the end of puberty. The third characteristic distinction that must be taken into consideration are certain habits and behaviour patterns of children where it is assumed that they influence the intake of substances. Today, it is not possible to give a definitive answer to the question whether a higher risk always results from a differentiated assessment of this kind. This is the result of the workshop "Exposure of Children to Pesticides" which was staged by the Federal Institute for Health Protection of Consumers and Veterinary Medicine, BgVV from 27 to 29 September 2001 within the framework of the Action Programme "Environment and Health".

A child's body does not always react more sensitively than that of an adult. As every paediatrician knows, medicinal products for "little patients" aged between one and six must be administered in higher doses than for adults. This is because the child's organism eliminates these substances more quickly. This probably also applies to chemicals which are broken down and excreted in the same way. At the same time, children when exposed to the same initial burden from the environment and foods for instance take in larger volumes of chemical substances than adults. For instance the skin surface compared to overall body is almost three times larger than that of adults. This leads to a higher overall burden of the child's body with regard to intake of substances through the skin. The differences are even greater in the case of substances which are taken in through the lungs. Children have a ventilation rate per square metre lung surface which is up to 60 times higher. This is of major relevance when it comes to the larger lung surface compared with body weight.

The toxic effects of chemicals must also be considered in a differentiated manner. When assessing the health risk, a very clear distinction must be made between substances and the target organ in which the toxic effect manifests itself. Another important factor is age: newly born babies, children of kindergarten age and young people must be considered separately because, for instance, the organs in the course of childhood develop at different rates and in different phases. If the brain or genital organs are affected during a critical phase, irreversible damage may occur. As the scale of effects of substances cannot be reliably estimated today, a higher sensitivity is assumed for children on precautionary grounds. This applies in particular to pesticides, a particularly important toxicological group, which include substances like organophosphates, pyrethroids and other pesticides. The target organ of these substances and products is the nervous system in insects and, by extension, in man.

Moreover, observation studies by American scientists have revealed that the behaviour particularly of children when they are crawling and during kindergarten influences the intake of substances. Particularly when at play, additional substances are taken in through contaminated fingers which children put in their mouths but also from contaminated toys and other objects. Hence, children probably take in far more substances through their mouths and thus intestines than adults. A probable intake source of pesticides is above all contaminated household dust in addition to food as the use of pesticides in the home can lead to contamination of that dust. Special caution is required when pets like dogs or cats are treated for pests. All these sources lead via mouthing behaviour to an increased burden.

In order to be able to realistically assess the health risk to children from pesticides and other chemicals, complex exposure models must be developed for individual products and product classes (like wood preservatives, pesticides, plant protection products and household chemicals). Data from biomonitoring studies can be drawn on in order to empirically underpin assessments of that kind. As up to now, only incomplete and unreliable data were available, a worst case scenario is always in principle assumed for precautionary reasons. In addition, methods are also developed for the assessments which cover the full spectrum of variability and data uncertainty (probability estimate). These methods also permit a distinction between individual risk groups. BgVV has already taken account of these uncertainties when examining the health risk from pesticides in the past to the extent that the available data permitted this.

The main reasons for separate assessments of the risks to children, therefore, result from that fact that the actual burden, the so-called exposure, is different in the case of children and can be estimated less reliably than in the case of adults. At present, it is still not clear whether in future an additional safety factor for children will have to be introduced, as is already the case in the USA, when assessing the risks from pesticides and other substances.

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