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Some observations on biological monitoring
203
Toxicology Letters, 33 (1986) 203-204 Elsevier
TOXLett.
1620s
SOME OBSERVATIONS
ON BIOLOGICAL
MONITORING
(Pesticides; breast feeding; herbicides) J.F.
COPPLESTONE
Pesticide Development and Safe Use Unit, Division of Vector Biology and Control, World Health Organization, 1211 Geneva (Switzerland)
When we discuss the subject of biological monitoring, it is necessary to realize that monitoring is not an activity on its own, but should go hand in hand with epidemiology. What happens when results of biological monitoring are published without taking into account the knowledge gathered from epidemiology can be illustrated with the case of mother’s milk. Publications on the amount of pesticide residues in mother’s milk, giving only the plain results without any attempt to determine the meaning of these in terms of adverse effects on man, have caused unnecessary alarm to nursing mothers, and sometimes adverse effects on the children through their being mistakenly deprived of their mother’s milk. Some alarmist press reports had an adverse influence on breast-feeding, particularly in the development countries. Many people do not realize that organochlorine pesticides have now been used for about 40 years, organophosphorus pesticides for 30 years and pyrethroids for 15 years. In the initial years of pesticide application much heavier exposures occurred than at present. There are, however, accumulating epidemiological indications of the non-carcinogenicity of a wide range of pesticides. Lower or normal cancer rates have been reported in areas in the U.S.A. where organochlorine pesticides were used in very high quantities in the 195Os, particularly on cotton. With respect to pyrethroids, it is known that this group of pesticides has a very good user-safety record (comparable with that of DDT). As far as herbicides are concerned, there is no convincing evidence that phenoxy compounds or their contaminants have teratogenetic or mutagenic effects in man. A range of studies have been carried out on the mutagenicity of pesticides. For many compounds equivocal results have been found in the laboratory, without any epidemiological effect having been reported. Nevertheless, ill-defined concern is expressed about the potential mutagenicity of some pesticides in man. The benefits of the use of pesticides are clear, e.g., the prevention of vector-borne diseases of humans, animals and plants, the promotion of food and fibre production and the combat of nuisance insects. Disadvantages are the adverse effects on human health after misuse of pesticides; these tend to be acute effects. The recent WHO Report of the Informal Consultation on Planning Strategy for 0378-4274/86/% 03.50 0 Elsevier
Science
Publishers
B.V. (Biomedical
Division)
204
the Prevention of Pesticide Poisoning (WHO unpublished document WHO/ VBU86.926, available from WHO Geneva) noted that most acute poisoning cases have been caused by carelessness. About 1 million cases of acute accidental poisoning occur every year but the mortality rate of about 1% is lower than previously expected. Slightly less than half the cases are of occupational origin. Biological monitoring assesses exposure and provide a basis for the definition of health risk provided that dose-effect/response relationships in man of the pesticide in question are known. These need to be established from data obtained from epidemiological studies. A neglected but important source of data is the poison control centre, where the nature and amount of toxicant ingested and the health effects can be recorded. An optimal use of this information for establishing human noeffect levels is strongly recommended. In this workshop most studies which have been presented were carried out in narrow environmental conditions, i.e., in formulation plants and during efficacy trials. Furthermore, the studies mainly concerned the monitoring of acute effects, if present, and the monitoring of absorbed dose. I would like to stress that more real field studies are needed at the endpoint of pesticide use, i.e., with the user. Different human ecological situations should be taken into account, such as the influence of such factors as temperature and humidity. In that context, a clear definition of ecological conditions should be an integral part of any survey report. In conclusion, monitoring is one of the best ways of advancing pesticide science and allaying public anxiety with a sense of responsibility.
Toxicology Letters, 33 (1986) 203-204 Elsevier
TOXLett.
1620s
SOME OBSERVATIONS
ON BIOLOGICAL
MONITORING
(Pesticides; breast feeding; herbicides) J.F.
COPPLESTONE
Pesticide Development and Safe Use Unit, Division of Vector Biology and Control, World Health Organization, 1211 Geneva (Switzerland)
When we discuss the subject of biological monitoring, it is necessary to realize that monitoring is not an activity on its own, but should go hand in hand with epidemiology. What happens when results of biological monitoring are published without taking into account the knowledge gathered from epidemiology can be illustrated with the case of mother’s milk. Publications on the amount of pesticide residues in mother’s milk, giving only the plain results without any attempt to determine the meaning of these in terms of adverse effects on man, have caused unnecessary alarm to nursing mothers, and sometimes adverse effects on the children through their being mistakenly deprived of their mother’s milk. Some alarmist press reports had an adverse influence on breast-feeding, particularly in the development countries. Many people do not realize that organochlorine pesticides have now been used for about 40 years, organophosphorus pesticides for 30 years and pyrethroids for 15 years. In the initial years of pesticide application much heavier exposures occurred than at present. There are, however, accumulating epidemiological indications of the non-carcinogenicity of a wide range of pesticides. Lower or normal cancer rates have been reported in areas in the U.S.A. where organochlorine pesticides were used in very high quantities in the 195Os, particularly on cotton. With respect to pyrethroids, it is known that this group of pesticides has a very good user-safety record (comparable with that of DDT). As far as herbicides are concerned, there is no convincing evidence that phenoxy compounds or their contaminants have teratogenetic or mutagenic effects in man. A range of studies have been carried out on the mutagenicity of pesticides. For many compounds equivocal results have been found in the laboratory, without any epidemiological effect having been reported. Nevertheless, ill-defined concern is expressed about the potential mutagenicity of some pesticides in man. The benefits of the use of pesticides are clear, e.g., the prevention of vector-borne diseases of humans, animals and plants, the promotion of food and fibre production and the combat of nuisance insects. Disadvantages are the adverse effects on human health after misuse of pesticides; these tend to be acute effects. The recent WHO Report of the Informal Consultation on Planning Strategy for 0378-4274/86/% 03.50 0 Elsevier
Science
Publishers
B.V. (Biomedical
Division)
204
the Prevention of Pesticide Poisoning (WHO unpublished document WHO/ VBU86.926, available from WHO Geneva) noted that most acute poisoning cases have been caused by carelessness. About 1 million cases of acute accidental poisoning occur every year but the mortality rate of about 1% is lower than previously expected. Slightly less than half the cases are of occupational origin. Biological monitoring assesses exposure and provide a basis for the definition of health risk provided that dose-effect/response relationships in man of the pesticide in question are known. These need to be established from data obtained from epidemiological studies. A neglected but important source of data is the poison control centre, where the nature and amount of toxicant ingested and the health effects can be recorded. An optimal use of this information for establishing human noeffect levels is strongly recommended. In this workshop most studies which have been presented were carried out in narrow environmental conditions, i.e., in formulation plants and during efficacy trials. Furthermore, the studies mainly concerned the monitoring of acute effects, if present, and the monitoring of absorbed dose. I would like to stress that more real field studies are needed at the endpoint of pesticide use, i.e., with the user. Different human ecological situations should be taken into account, such as the influence of such factors as temperature and humidity. In that context, a clear definition of ecological conditions should be an integral part of any survey report. In conclusion, monitoring is one of the best ways of advancing pesticide science and allaying public anxiety with a sense of responsibility.