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Report of the government chemist 1975
Fd Cosmer. Joxicol.
Vol. IS. pp. 231-238. Pergamon Prar
REVIEWS
1977. Printed in Great Britain
OF RECENT
PUBLICATIONS
rats and mice. The induction of local sarcomas after repeated injection features prominently also in many of the monographs in Volume 10, including those on Research on Cancer, Lyon, 1976. pp. 353. Sw.fr. actinomycins, parasorbic acid, patulin, penicillic acid 3mo*. and mitomycin C. It is true that major attention is paid to the effects of administering materials by routes more relevant to actual human exposure (inIARC Monographs on the Evaluation of Carcinogenic gestion, inhalation and skin contact) and that the Risk of Chemicals to Man. Cadmium, Nickel, Some reader is referred to an introductory comment quesEpoxides, Miscellaneous Industrial Chemicals and tioning the validity of the subcutaneous sarcoma as General Considerations on Volatile Anaesthetics. Vol. an index of carcinogenicity, but no assessmentof the 11. International Agency for Research on Cancer, significance of such data appears in the individual Lyon, 1976. pp. 306. Sw.fr. 34.00*. monographs. Similarly, no attempt has been made to distinguish, in terms of relative risk to man, between The first volume cited above is devoted to the compounds that induce tumours (particularly of the evaluation of the carcinogenicity of some metabolic liver) only when administered in very high doses (e.g. products of plants and fungi. Four of the substances coumarin) and others, like aflatoxin, that are tumorior groups of substances considered, namely the afla- genie in doses of only a few micrograms. These points illustrate what some would consider toxins, cycasin, sterigmatocystin and safrole and its to be a major deficiency in this series. The monorelated compounds, figured in the first volume in this series,published in 1972 (Cited in F.C.T. 1974,12, 243). graphs collect together from scattered sources a great The carcinogenicity of the allatoxins and cycasin to deal of information of considerable value to toxicolovarious species is now more fhmly established and gists and others faced with the task of assessingsubnew epidemiological data support the earlier sus- stances in terms of their carcinogenic risk to man. picions that the aflatoxins are carcinogenic to man. In this way they perform a very useful function, but Newly acquired data have also confirmed the produc- for the most part the experts involved in their compition of liver tumours by safrole in rats and mice and lation give little guidance on the significance of the additional metabolites have been identified in several data presented. The user of these monographs must not be misled by the title of the series, as he will species. have to depend upon his own judgement as far as The eleventh volume in the series also includes some up-dated monographs, those on cadmium and any evaluation of probable human carcinogenicity is nickel having appeared first in Volume 2 (ibid 1974, concerned. 12, 244). Most of the new information supports the earlier observations on the carcinogenicity of these two metals. Both induce tumours in experimentai ani- Report of the Government Chemist 1975. Department mals when administered subcutaneously, and nickel of Industry: Laboratory of the Government Chemist. has been shown to be carcinogenic also in inhalation HMSO, London, 1976. pp. iv + 158. f2.10. studies. While epidemiological evidence indicates that some forms of nickel are carcinogenic to man, the The Laboratory has for many years been involved evidence on cadmium is much less convincing-in fact many workers consider it to be of little value. in sampling foodstuffs for pesticide residues, and Volume 11 also presents monographs on various periodically this activity has been extended to a calcuepoxide compounds and on a miscellaneous group lation of pesticide intakes in the total daily diet. The of chemicals of importance chiefly in connexion with last comprehensive survey in 1970-71 showed that industrial exposure, and makes some general com- levels of dieldrin and DDT and its degradation prodments on volatile anaesthetics. The Working Group ucts had decreased since the first survey in 1966-67, responsible for the latter contribution considered that whereas y-BHC had remained relatively constant and the environment of the operating theatre presented malathion had increased markedly (Cited in F.C.T. some carcinogenic hazard but did not ascribe re- 1974, 12, 747). A third survey conducted during 1974-75 has now revealed a dramatic fall in the levels sponsibility to any specific anaesthetics. of malathion, to below even that recorded in the iniSome of the miscellaneous industrial chemicals considered in this volume are undoubtedly carcino- tial survey, accompanied by further slight declines in genic to animals, but although the epoxides are both the levels of organochlorines (including y-BHC). The industrially important and biologically reactive, the average daily intakes calculated were 4.4pg for y-BHC, 1.9 pg for dieldrin, 12 E for DDT, TDE and main evidence for their carcinogenic activity rests on DDE combined and 7pg for malathion, the last constudies involving repeated subcutaneous injection in trasting with a peak of 53pg during 197&71. In all cases,levels were only a fraction of the ADIs allo*Available in the UK from HMSO. cated by FAO/WHO. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man. Some Naturally Occurring Substances. Vol. 10. International Agency for
231
238
Reviewsof recent publications
Other work on pesticidesduring the year included the development of analytical methods for dithiocarbamates and their degradation products, including ethylene thiourea, which may possibly be limited in the future in specifications for formulated products. In connexion with the fact that chlorophenol fungicides in wood shavings used as litter may give rise to taint in broiler chickens, the Laboratory has been investigating techniques of extraction and clean-up and limits of detection for chlorophenols in poultry meat. This investigation was requested by a subgroup of the Steering Group on Food Surveillance, set up to report on the “effect on wholesomeness of food of the use of wood litter in poultry management”. In the realm of animal feeding stuffs, the Laboratory has been engaged in the development of methods for the determination of goitrogenic thioglucoside derivatives, to provide substitutes for the somewhat unsatisfactory method at present prescribed in the relevant EEC directive. A method for the determination of uric acid has been developed and forwarded to MAFF for possible inclusion in the Fertilizer and Feeding Stuffs Regulations, should it be decided that the use of dried poultry waste in feeds should be controlled. The Laboratory has also participated in a collaborative study of the determination of copper, iron, manganese and zinc in feeding stuffs by atomic absorption spectrophotometry, as a result of which the method used was deemed acceptable for publication. In human foods the range of trace elements monitored under the total diet study was extended in 1975 to include arsenic, copper, iron, manganese, nickel and zinc. Representative dietary items were also analysed for arsenic on behalf of the MAFF Working Party on the Monitoring of Foodstuffs for Heavy Metals, a survey which should provide information useful for the intended review of the Arsenic in Food Regulations 1959. Work on the revision of the nutritional tables for The Composition of Foods reached an advanced stage, and a new edition should be published in 1977. Although analysis of dry tea leaves has suggested that tea may be a rich source of nutrient metals, a study of tea infusions revealed that a major part of the metal content does not pass into the brew. In a representative sample more than 95% of the iron content was found to be retained by the
leaf, together with 85% of the copper, 70% of the manganese, 65% of the zinc and 55% of the nickel, while on the benefit side the toxic metals cadmium and lead were retained to the extent of 65 and 45x, respectively. Routine examination of drinking-water brought to light several cases where the WHO limits for lead and copper were exceeded, and one case in which the cadmium concentration, at 0.02 mg/litre, was twice the WHO limit, necessitating corrective action. Lead (28-33 mg/litre) released by two silver-plated tankards subjected to the usual extraction test with 4”/, acetic acid was apparently the result of extraction from solder through the nickel-silver plating. However, new pewter articles conforming to BS 5140:1974 yielded insignificant amounts of soluble lead. The Laboratory also collaborated in developing methods of sample preparation for inclusion in a proposed European standard on the safety of toys, which will extend the toxic-metal limits now specified for paints to other materials such as plastics and printed paper and card. Following complaints of discomfort to the eyesand nose in a Department of the Environment building where textiles treated with urea-formaldehyde resin were stored, tests were conducted for atmospheric formaldehyde, but all levels were well below the TLV of 2 ppm. A similar complaint that eye irritation had resulted from the use of a foam-backed ironing-board cover led to the setting up of an experiment in which the air was analysed continuously for hourly periods above the covered ironing board, on which a mechanically-driven iron was made to function in a closed compartment. Concentrations of toluene diisocyanate were found to reach a maximum of one third of the TLV, and it was concluded that in a particularly sensitive person this could have produced the reported symptoms. After the tragic death from cyanide poisoning of a small child, who had thrown a teddy bear filled with acrylic fibre on to an electric fire, it was found that even at 200°C the fibre could yield up to 5 mg HCN/g and at 300” up to ten times this amount could be produced. As alternative fillings such as polyurethane crumb are more flammable and can also yield toxic fumes, further research into the problem is now in progress at the Fire Research Station.
Vol. IS. pp. 231-238. Pergamon Prar
REVIEWS
1977. Printed in Great Britain
OF RECENT
PUBLICATIONS
rats and mice. The induction of local sarcomas after repeated injection features prominently also in many of the monographs in Volume 10, including those on Research on Cancer, Lyon, 1976. pp. 353. Sw.fr. actinomycins, parasorbic acid, patulin, penicillic acid 3mo*. and mitomycin C. It is true that major attention is paid to the effects of administering materials by routes more relevant to actual human exposure (inIARC Monographs on the Evaluation of Carcinogenic gestion, inhalation and skin contact) and that the Risk of Chemicals to Man. Cadmium, Nickel, Some reader is referred to an introductory comment quesEpoxides, Miscellaneous Industrial Chemicals and tioning the validity of the subcutaneous sarcoma as General Considerations on Volatile Anaesthetics. Vol. an index of carcinogenicity, but no assessmentof the 11. International Agency for Research on Cancer, significance of such data appears in the individual Lyon, 1976. pp. 306. Sw.fr. 34.00*. monographs. Similarly, no attempt has been made to distinguish, in terms of relative risk to man, between The first volume cited above is devoted to the compounds that induce tumours (particularly of the evaluation of the carcinogenicity of some metabolic liver) only when administered in very high doses (e.g. products of plants and fungi. Four of the substances coumarin) and others, like aflatoxin, that are tumorior groups of substances considered, namely the afla- genie in doses of only a few micrograms. These points illustrate what some would consider toxins, cycasin, sterigmatocystin and safrole and its to be a major deficiency in this series. The monorelated compounds, figured in the first volume in this series,published in 1972 (Cited in F.C.T. 1974,12, 243). graphs collect together from scattered sources a great The carcinogenicity of the allatoxins and cycasin to deal of information of considerable value to toxicolovarious species is now more fhmly established and gists and others faced with the task of assessingsubnew epidemiological data support the earlier sus- stances in terms of their carcinogenic risk to man. picions that the aflatoxins are carcinogenic to man. In this way they perform a very useful function, but Newly acquired data have also confirmed the produc- for the most part the experts involved in their compition of liver tumours by safrole in rats and mice and lation give little guidance on the significance of the additional metabolites have been identified in several data presented. The user of these monographs must not be misled by the title of the series, as he will species. have to depend upon his own judgement as far as The eleventh volume in the series also includes some up-dated monographs, those on cadmium and any evaluation of probable human carcinogenicity is nickel having appeared first in Volume 2 (ibid 1974, concerned. 12, 244). Most of the new information supports the earlier observations on the carcinogenicity of these two metals. Both induce tumours in experimentai ani- Report of the Government Chemist 1975. Department mals when administered subcutaneously, and nickel of Industry: Laboratory of the Government Chemist. has been shown to be carcinogenic also in inhalation HMSO, London, 1976. pp. iv + 158. f2.10. studies. While epidemiological evidence indicates that some forms of nickel are carcinogenic to man, the The Laboratory has for many years been involved evidence on cadmium is much less convincing-in fact many workers consider it to be of little value. in sampling foodstuffs for pesticide residues, and Volume 11 also presents monographs on various periodically this activity has been extended to a calcuepoxide compounds and on a miscellaneous group lation of pesticide intakes in the total daily diet. The of chemicals of importance chiefly in connexion with last comprehensive survey in 1970-71 showed that industrial exposure, and makes some general com- levels of dieldrin and DDT and its degradation prodments on volatile anaesthetics. The Working Group ucts had decreased since the first survey in 1966-67, responsible for the latter contribution considered that whereas y-BHC had remained relatively constant and the environment of the operating theatre presented malathion had increased markedly (Cited in F.C.T. some carcinogenic hazard but did not ascribe re- 1974, 12, 747). A third survey conducted during 1974-75 has now revealed a dramatic fall in the levels sponsibility to any specific anaesthetics. of malathion, to below even that recorded in the iniSome of the miscellaneous industrial chemicals considered in this volume are undoubtedly carcino- tial survey, accompanied by further slight declines in genic to animals, but although the epoxides are both the levels of organochlorines (including y-BHC). The industrially important and biologically reactive, the average daily intakes calculated were 4.4pg for y-BHC, 1.9 pg for dieldrin, 12 E for DDT, TDE and main evidence for their carcinogenic activity rests on DDE combined and 7pg for malathion, the last constudies involving repeated subcutaneous injection in trasting with a peak of 53pg during 197&71. In all cases,levels were only a fraction of the ADIs allo*Available in the UK from HMSO. cated by FAO/WHO. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man. Some Naturally Occurring Substances. Vol. 10. International Agency for
231
238
Reviewsof recent publications
Other work on pesticidesduring the year included the development of analytical methods for dithiocarbamates and their degradation products, including ethylene thiourea, which may possibly be limited in the future in specifications for formulated products. In connexion with the fact that chlorophenol fungicides in wood shavings used as litter may give rise to taint in broiler chickens, the Laboratory has been investigating techniques of extraction and clean-up and limits of detection for chlorophenols in poultry meat. This investigation was requested by a subgroup of the Steering Group on Food Surveillance, set up to report on the “effect on wholesomeness of food of the use of wood litter in poultry management”. In the realm of animal feeding stuffs, the Laboratory has been engaged in the development of methods for the determination of goitrogenic thioglucoside derivatives, to provide substitutes for the somewhat unsatisfactory method at present prescribed in the relevant EEC directive. A method for the determination of uric acid has been developed and forwarded to MAFF for possible inclusion in the Fertilizer and Feeding Stuffs Regulations, should it be decided that the use of dried poultry waste in feeds should be controlled. The Laboratory has also participated in a collaborative study of the determination of copper, iron, manganese and zinc in feeding stuffs by atomic absorption spectrophotometry, as a result of which the method used was deemed acceptable for publication. In human foods the range of trace elements monitored under the total diet study was extended in 1975 to include arsenic, copper, iron, manganese, nickel and zinc. Representative dietary items were also analysed for arsenic on behalf of the MAFF Working Party on the Monitoring of Foodstuffs for Heavy Metals, a survey which should provide information useful for the intended review of the Arsenic in Food Regulations 1959. Work on the revision of the nutritional tables for The Composition of Foods reached an advanced stage, and a new edition should be published in 1977. Although analysis of dry tea leaves has suggested that tea may be a rich source of nutrient metals, a study of tea infusions revealed that a major part of the metal content does not pass into the brew. In a representative sample more than 95% of the iron content was found to be retained by the
leaf, together with 85% of the copper, 70% of the manganese, 65% of the zinc and 55% of the nickel, while on the benefit side the toxic metals cadmium and lead were retained to the extent of 65 and 45x, respectively. Routine examination of drinking-water brought to light several cases where the WHO limits for lead and copper were exceeded, and one case in which the cadmium concentration, at 0.02 mg/litre, was twice the WHO limit, necessitating corrective action. Lead (28-33 mg/litre) released by two silver-plated tankards subjected to the usual extraction test with 4”/, acetic acid was apparently the result of extraction from solder through the nickel-silver plating. However, new pewter articles conforming to BS 5140:1974 yielded insignificant amounts of soluble lead. The Laboratory also collaborated in developing methods of sample preparation for inclusion in a proposed European standard on the safety of toys, which will extend the toxic-metal limits now specified for paints to other materials such as plastics and printed paper and card. Following complaints of discomfort to the eyesand nose in a Department of the Environment building where textiles treated with urea-formaldehyde resin were stored, tests were conducted for atmospheric formaldehyde, but all levels were well below the TLV of 2 ppm. A similar complaint that eye irritation had resulted from the use of a foam-backed ironing-board cover led to the setting up of an experiment in which the air was analysed continuously for hourly periods above the covered ironing board, on which a mechanically-driven iron was made to function in a closed compartment. Concentrations of toluene diisocyanate were found to reach a maximum of one third of the TLV, and it was concluded that in a particularly sensitive person this could have produced the reported symptoms. After the tragic death from cyanide poisoning of a small child, who had thrown a teddy bear filled with acrylic fibre on to an electric fire, it was found that even at 200°C the fibre could yield up to 5 mg HCN/g and at 300” up to ten times this amount could be produced. As alternative fillings such as polyurethane crumb are more flammable and can also yield toxic fumes, further research into the problem is now in progress at the Fire Research Station.