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Dietary intake of pesticide residues: Cadmium, mercury, and lead H. Galal‐Gorchev
a
a
International Programme on Chemical Safety , World Health Organization , Geneva, Switzerland Published online: 10 Jan 2009.
To cite this article: H. Galal‐Gorchev (1991) Dietary intake of pesticide residues: Cadmium, mercury, and lead, Food Additives & Contaminants, 8:6, 793-806, DOI: 10.1080/02652039109374038 To link to this article: http://dx.doi.org/10.1080/02652039109374038
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FOOD ADDITIVES AND CONTAMINANTS, 1991, VOL. 8, NO. 6, 7 9 3 - 8 0 6
Dietary intake of pesticide residues: cadmium, mercury, and lead H. GALAL-GORCHEV
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International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland (Received 13 August 1991; revised 1 October 1991; accepted 4 October 1991) Information on the dietary intake of chemical contaminants has been obtained from institutions participating in GEMS/Food. Contaminants studied include certain organochlorine and organophosphorous pesticides, PCBs, cadmium, mercury, and lead. The intakes are compared with toxicologically acceptable intake levels established by international expert groups. In most cases, dietary intakes of organochlorine and organophosphorous pesticides are well below the Acceptable Daily Intake (ADI) of the respective pesticide. Of some 21 countries providing information on the average dietary intake of cadmium, only in one case is the Provisional Tolerable Weekly Intake (PTWI) exceeded. Several countries identified cereals and cereal products and root and tuber vegetables as the main contributors to the dietary intake of cadmium. For mercury, all reported intakes are below the PTWI of methylmercury. The contribution of fish to the total intake of mercury varied from 20% to 85%, depending on the country. Therefore, the general assumption that fish is the main contributor to the total dietary intake of mercury may, at times, not be justified. Average dietary intake of lead exceeding or approaching the PTWI are reported for adults and infants and children in some countries. Foodstuffs which contribute most to the intake of lead vary from country to country, and have been identified as being alternately drinking water, beverages, cereals, vegetables and fruit. Keywords: dietary intake, pesticide residues, cadmium, mercury, lead
Introduction
The Joint UNEP/FAO/WHO Food Contamination Monitoring Programme, or GEMS/Food, is a component of the Global Environment Monitoring System (GEMS) established by the United Nations Environment Programme. The major objective of the Programme is to collect, assess, and disseminate information on levels and trends of contaminants in food, the magnitude of dietary exposure and the significance with regard to public health. At present 39 countries participate in GEMS/Food, and through the active collaboration of these countries, information has been obtained on levels and trends of chemical contaminants in food and magnitude of dietary exposure. Information on the dietary intake of contaminants is of special health interest since by comparison with acceptable or tolerable intake levels, a determination can be made as to whether or not consumers are likely to be at risk. In order to encourage international cooperation in such exposure studies, Guidelines for the Study of Dietary Intake of Chemical Contaminants have been published (WHO 1985). The Guidelines provide a detailed description of procedures and methods by which dietary intake studies may be conducted and have encouraged several 0265-203X/91 $3.00 © 1991 Taylor & Francis Ltd.
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countries to conduct such studies, and to make available the information to GEMS/Food. Such dietary exposure assessment will enable national health authorities to make sound decisions in the regulation of chemical contaminants in food, and thus ensure the safety of the food supply with respect to these substances. Since 1980, information on contaminants in total diets has been collected by GEMS/Food. Summary reports of these data have been issued (GEMS/Food 1986a, 1988, 1991) and periodic assessment of the data carried out (GEMS/Food 1982, 1986b, UNEP/FAO/WHO 1988). Information recorded includes the mean, median and 90th percentile values. However, most countries provide information on the mean intake only. The composition of the diet, preparation for analysis, total weight of the diet and study approach vary widely from country to country. For instance, the amount of food consumed may be purposely exaggerated (3 • 3 kg/day) in order to protect extreme consumers; drinking water and alcoholic beverages may or may not be included in the diet; foods may not be cooked prior to analysis; the number of foods analysed can vary from 10 to over 100; and finally, the methodology used in estimating the daily intake of a contaminant varies from country to country. Because of such differences, while trends within a country may at times be established, comparisons between countries should be done with caution. Three basic approaches can be used to determine intake (WHO 1985): (a) Total diet (i.e. market basket) studies. The sample for this type of study consists of a market basket of food reflecting a defined total diet of a consumer for a specific period of time. The foods are prepared for table-ready consumption and are analysed either individually or combined in one or more food-group composites (e.g. cereals, meat, root vegetables, etc.) in proportions based on available consumption data. Residue levels measured in the total diet samples are used in calculating the average daily intake for each composite and for the diet as a whole. A total diet study is particularly valuable in initially determining whether residues are widely distributed among all the broad classes of major foods, or are confined to a few general classes of foods, e.g. fruit, vegetables. (b) Selective studies of individual foodstuffs. This approach involves measurement of residue levels in representative samples of staple foods, either raw or cooked, which, together with food consumption data, enables average daily intakes to be calculated. Such an approach is particularly useful if the intake of a contaminant is predominantly influenced by one or two commodities and/or when food contamination monitoring programmes have established average residue levels in the commodities. In combination with food consumption surveys, it is possible to obtain a reasonable assessment of exposure in selected consumer groups. (c) Duplicate portion studies. Representative diets of individuals can be collected over a period of days by requesting that institutions or an individual provide, for residue analysis, a duplicate sample of the meals consumed. Such an approach has been successfully used in residue intake studies in well-defined populations. Depending on the objectives of the assessment and the resources available, all three approaches have been used by countries participating in GEMS/Food. Organochlorine compounds Available information on the average intake by adults of various organochlorine pesticides and PCBs are given in table 1. The intakes are reported
Dietary intake of chemical contaminants
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Table 1. Mean dietary intake, % of ADI (adults, most recent year). Country (year of study) ADI Australia Egypt Finland Guatemala Japan New Zealand Thailand UK USA Compound (;ug/kg bw) (1987) (1988) (1986) (1988) (1988) (1982) (1987) (1985) (1988)
Aldrin/ dieldrin
0-1 20 6 0-2 0-5 8
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DDT
Endosulfan Endrin Heptachlor Lindane HCB b HCH b PCBsb
7-0 a 0-l a l-4 a l-0 a
1364 0-1
68
1194 125
0-03 0-03
ND
7-8 0-2 1-6 0-9 0-4
3-0 0-1
0-02
0-02 ND 0-01 0-04
ND ND
0-01
ND
0-04
7-1
0-01
ND
0-04 0-07
3-9 0-4
0-03 0-2
0-8
0-09 0-01 ND
0-03
ND ND ND
a
95th percentile consumer. No ADI established, intakes in jjg/kg bw/day. ND = Not Detected. b
as percentages of the respective acceptable daily intake (ADI) established by the Joint FAO/WHO Meeting on Pesticide Residues (IPCS 1990). In Egypt, the intakes of aldrin/dieldrin and endrin are about ten times the ADI; in the case of lindane and DDT, the intake was 125% and 68% of the ADI, respectively (Abdel-Gawaad and Shams El Dine 1989). The high intake of organochlorine pesticides in Egypt warrants further investigation. For the other countries, mean intakes in recent years are all below 10% of the respective ADIs and in most cases the intakes are less than 1 % of the ADI. Australia and the USA provided information on the dietary intake of the adult population as well as various other population groups such as infants, 2-year old Adults 26 2422201816 ^ 14 12 S
108 64 2 0
1—
1980
1981
1983
1982 D
Japan
1984
1985 A
1986
1987
USA
Figure 1. Mean intake of aldrin and dieldrin—adults.
—I 1988
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H. Galal-Gorchev
children, boys and girls aged 14-16 years, etc. In the USA, intakes of organochlorine pesticides by the 6-11-month old infant, and the 2-year old child are in many cases 2-4 times that of an adult on a kg/bw basis. In the case of Australia, no clear trend could be seen between the intake of various population groups. For countries reporting intakes over several years, a downtrend is noticeable as shown in figure 1 for the intake of aldrin/dieldrin in Japan and the USA.
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Organophosphorus pesticides
In the case of the organophosphorus pesticides, diazinon, fenitrothion, malathion, methyl parathion and parathion, mean intakes reported by Guatemala, Japan, New Zealand, Thailand and the USA are below l°7o of the respective ADIs, and in the majority of cases these compounds were not detected in total diet studies. The only exception was in the case of Australia which reported an intake of fenitrothion by the 95th percentile consumer of about 50% of the ADI, and recommended that the significance of this finding be assessed by the authorities concerned (NHMRC 1990). Cadmium
International recommendations In 1988, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established a Provisional Tolerable Weekly Intake (PTWI) of cadmium from all sources of 7 /tg/kg bw, applicable to adults as well as infants and children. The PTWI from all sources was derived from estimated accumulation over a period of 50 years at an exposure rate equivalent to 1 fig/kg bw for adults; excursions above this figure may therefore be tolerated provided that they are not sustained for long periods of time. In addition, JECFA estimated the dietary intake of cadmium to be usually 1-4 /tg/kg bw/wk, and recognized that '...there is only a relatively small safety margin between exposure in the normal diet and exposure that produced deleterious effects.' Consequently, JECFA recommended that levels of cadmium in foods and total diet should continue to be monitored, and should not increase further (WHO 1989a). A guideline value of 0-005 mg/litre has been recommended for cadmium in drinking-water (WHO 1984). This value is at present under review. The International Organization for Standardization established maximum limits for the release of cadmium from ceramic ware of 0-17mg/dm2 for flatware and 0-25-0-50 mg/litre of extraction solution for hollow-ware (ISO 1982). Dietary intake of cadmium Average adult intake in different countries for the most recent year provided (over the period 1981-88) are presented in figure 2. With the exception of Thailand, all reported intakes are below the PTWI of 7 /tg/kg bw for cadmium. No particular time trend in intake was noticeable for those countries providing information over several years. Canada, Denmark, Finland, The Netherlands, and the USA identified cereals and their products, followed by potatoes and other vegetables, as the largest contributors to such intake. Fruit, meat, poultry, and dairy products contributed little to the intake.
Dietary intake of chemical contaminants
797
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Adults, 1981-1988
THA NZE POL GUA FRA ITA JPN AUS NET GER CUB UK BEL DEN SWI CAN SWE FIN USA TUR HUN
Figure 2. Average intake of cadmium—adults, 1981-1988.
High cadmium levels are found in animal kidney and shellfish. In Belgium, it was noted that once-a-week consumption of mussels or kidney would result in a mean intake that would approximate the PTWI (Fouassin and Fondu 1980). Similarly, in Denmark (Andersen 1981) above average consumption of beef kidney, mussels from contaminated water, or wild mushrooms, yield intakes that exceed the PTWI. In Poland, intake of cadmium by populations living in industrial areas was about double that of populations in non-industrial areas. Several countries provided information on intakes of cadmium by infants and children (Australia, Canada, Cuba, Germany, Hungary, Poland, Sweden, UK and USA). Intakes on a kg/bw basis for infants and children of varying ages are higher than those of the adult population in these same countries. However, none of these intakes exceed the PTWI. In Sweden, the intake of cadmium by exclusively breastfed infants is appreciably less than that of adults, indicating the low level of contamination of human milk by cadmium. The average dietary intake of cadmium by Canadian infants who were given milk-based formula or human milk amounted to 3 fig/kg bw/wk. Feeding infants soya-based formula increased the intake to 5 fig/kg bw/wk (Dabeka 1989). Cadmium in food and estimated intake Some 20 institutions participating in GEMS/Food provided information on the concentration of cadmium in food. Typical cadmium levels in various foods are given in figure 3. Levels in dairy milk and products, eggs, fats and oils, nuts, and human milk, were usually at or below the limits of detection. High levels of cadmium are found in kidneys and shellfish, with extremely high levels found at times in lobster and crab bodies. Most fish species, cereals, root and tuber vegetables, as well as other vegetables, contain relatively low cadmium levels. Monitoring data on average contaminant levels in food, together with food consumption data, can be used to obtain rough estimates of intakes. In the absence
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350
Offal
Shellfish
Cereals
Roots
Fish
Figure 3. Typical cadmium levels in food, 1980-1988.
of dietary intake studies, this approach can be used to make a preliminary assessment of likely dietary exposure and to tentatively identify foods that are major contributors to the intake. GEMS/Food survey data, together with a hypothetical 'global' diet, are used in table 2 to illustrate such an approach. The global diet, which is representative of an 'average' adult, is based on FAO Food Balance Sheets, and has been developed following the recommendations of the Joint FAO/WHO Consultation on Guidelines for Predicting Dietary Intake of Pesticide Residues. It is being used to predict intake of pesticide residues (WHO 1989b). This global diet is obtained from the highest average food consumption Table 2. Estimated intake of Cd based on global diet and GEMS/Food data.
Commodity Cereals Roots and tubers Fruit Vegetables Meat Fish Shellfish Offal Other foods Total
Global diet (g/day)
Typical Cd levels (mg/kg)
Estimated intake (fg/day)
405 301 236 182 105 33 6 6 226
0-03 0-02 0-003 0-009 0-006 0-02 0-2 0-3 0-002
12-2 6-0 0-7 1-6 0-6 0-7 1-2 1-8 0-5
1500
% of total intake 48 24 3 6 2 3 5 7 2
100 25 or 3 (ig/kg bw/wk (PTWI = 7 /ig/kg bw)
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Dietary intake of chemical contaminants
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values from five regional diets and normalizing to a total daily consumption of 1-5 kg of solid food, i.e. excluding the liquid content of juices or milk. Better intake estimates can, of course, be obtained where national monitoring and food consumption data are used. The percent contribution of various foods to the total intake of cadmium, based on the global diet and typical levels of cadmium in food, are given in table 2. Relatively low levels of cadmium are found in cereals and root and tuber vegetables; nevertheless, concording with the information provided by several countries, these foodstuffs, because of their high consumption, contribute most to the total intake. Offal and shellfish contribute a total of about 10% to the overall intake of cadmium. Steps aimed at reducing the concentration of cadmium in cereals and root and tuber vegetables, the main contributors to the total intake, would be most effective in avoiding an increase in cadmium intake. JECFA identified several sources of contamination of food by cadmium: phosphate fertilizers and sewage sludge used on agricultural land, use of cadmiumplated utensils and galvanized equipment in food processing and preparation, leachable cadmium in enamel and pottery glazes and cadmium-based pigments or stabilizers used in food-contact plastics (WHO 1989a). Effective control of such sources would avoid increases in levels of cadmium in foods and total diet. Mercury International recommendations JECFA established a PTWI of 300 fig of total mercury per person, of which no more than 200 ^g should be present as methylmercury. These amounts are equivalent to 5 ^g/kg bw and 3-3 /*g/kg bw respectively (WHO 1972). In 1988, the Committee re-assessed methylmercury as new data were only then available for this compound, and confirmed the previously recommended PTWI of 200 ng of methylmercury (3-3 /ig/kg bw) for the general population, but noted that pregnant women and nursing mothers are likely to be at greater risk from the adverse effects of methylmercury. The available data were considered insufficient to recommend a specific methylmercury intake for this population group (WHO 1989a). A guideline value of 0*001 mg/litre has been recommended for mercury in drinking-water (WHO 1984). Dietary intake of mercury Adults. Dietary intakes for the most recent year provided by countries (between 1981 and 1988) are given in figure 4. All intakes are below the PTWI of methylmercury of 3-3 ftg/kg bw. The contribution of fish to the total dietary intake of mercury varies from a low of 20% in Belgium, Germany, and The Netherlands, to a high of 85% in Finland and the USA, with France and the UK in between (35%). The Netherlands provided information on levels of mercury in different foods: higher concentration of mercury is found in fish (about 0-1 mg/kg) than in other foods (0'01 mg/kg or less). However, because of higher consumption, the contributions of food groups such as cereals and meat to the total intake were about the same as that from fish. Therefore, the general assumption that fish is the main contributor to the total dietary intake of mercury may, at times, not be justified.
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Adults, 1981-1988
9
I
GER
BEL
GUA
DEN
ITA
NET
THA
NZE
SWE
UK
USA
AUS
FIN
Figure 4. Average intake of mercury—adults, 1981-1988.
Infants. The dietary intakes of mercury by exclusively breast-fed 3-month old infants are given in figure 5 for Sweden, Nigeria, Zaire, the Philippines, Guatemala and Hungary (WHO 1989c). For comparison purposes, the USA reported a 1988 weekly intake by a 6-11-month old infant of 0-4 jig/kg bw. The Swedish value is significantly higher than those for other study areas. 'It is possible that this increased mercury content of human milk be related to the fact that much fish is consumed in the country, but this requires further investigation.' (WHO 1989c). Breast-fed infants
Sweden
Nigeria
Zaire
Philippines
Guatemala
Figure 5. Median intake of mercury—breast-fed infants.
Hungary
Dietary intake of chemical contaminants
801
Mercury in fish and estimated intake Typical levels reported to GEMS/Food for total mercury in fish were in the vicinity of 0-2mg/kg. Inadequate data are available to GEMS/Food on levels of mercury in food other than fish. The 'global' consumption of fish and shellfish is 40 g/day. Assuming a level of methylmercury of 0*2 mg/kg, the estimated weekly intake is about 1 /tg/kg bw in comparison to the PTWI of 3 -3 /xgjkg bw for methylmercury. This estimated intake does not take into account possible exposure from food other than fish.
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Lead International recommendations In 1972, JECFA established a PTWI of lead of 50/ig/kg bw, applicable to adults only (WHO 1972); this PTWI was reconfirmed in 1978 (WHO 1978). Because of the special concern for infants and children, JECFA later evaluated the health risks of lead to this group and established a PTWI of 25 /ig/kg bw. This level refers to lead from all sources (WHO 1987). A guideline value of 0-05 mg/litre has been recommended for lead in drinkingwater (WHO 1984). This value is at present under review. Within the Joint FAO/WHO Food Standards Programme, maximum levels of 0-2 mg/kg to 2>0 mg/kg have been established for lead in a number of foods such as sugars, cocoa products, and fruit juices (FAO/WHO 1984). The International Organization for Standardization established maximum limits for the release of lead from ceramic ware of W m g / d m 2 for flatware and 2-5-5-0 mg/litre of extraction solution for hollow-ware (ISO 1982). Dietary intake of lead Adults. Information on the most recent intake of lead by adults in different countries is given in figure 6. Intakes slightly exceeding or approaching the PTWI are reported for the average adult in Cuba (1984), Italy (1982) and Thailand (1987). The lowest intake is reported by the USA (1988). There are thus considerable differences in lead intakes reported from different countries. Whether these differences are real or partly due to factors associated with the study approach, remains to be assessed. Inadequacies in analytical quality control may also account for some of the differences. In a 1987 study in Australia (NHMRC 1990), lead intake of the 95th percentile consumer was approximately four times the intake of the average consumer. Intake of the average person in a country if approaching the PTWI, should be viewed with some concern since a certain segment of the population, because of varying dietary habits, may exceed the PTWI. Increases in lead intake were noted in some countries with consumption of wine, for populations living in industrial areas and in areas where lead concentrations in tap water are higher than average. Some countries have provide dietary intake information to GEMS/Food over several years. Trends in lead intake are shown for some countries in figure 7. It appears that a downward trend in lead intake has taken place in the UK and the USA. The decreasing trend in the USA coincides, in the early 1980s, with a reduction in the use of lead-soldered cans, and also in the lead content of petrol.
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Adults, 1981-1988
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60-
Cub
Ita Tha Gua HZ
Bel Fra Pol Ire Ger Hun Jpn UK Tur Can Net Den AUS Swi Swe Fin US
Figure 6. Average intake of lead—adults, 1981-1988.
Foodstuffs which contribute most to the total intake of lead by adults vary from country to country, and have been identified as being alternatively drinkingwater, beverages, cereals, vegetables and fruit. In spite of high levels of lead that may be found in canned food, these foods, because of their relatively low consumption, were not identified as major contributors to the intake.
1988
D
USA
o
Japan
a
Hungary
Figure 7. Trends in lead intake by adults.
803
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Infants and children. Relatively few countries report dietary intake of lead by infants and children. The intake by infants and children up to 12 years of age are given in figure 8. Since the PTWI of lead for infants and young children refers to the maximum intake from all sources (food, water, air, dust, etc.) the average intake from food should be well below the PTWI of 25 /*g/kg bw to allow for exposure from other media (WHO 1987). In Hungary (1983), in a children's home, intake of 3-6-year olds was about double the PTWI, while for breast-fed infants, the intake amounted to half the PTWI. Intake greater than the PTWI was reported in Poland (1985) and Germany (1980). In a 1984 study in Poland, the intake of children living in industrial areas amounted to 35 ^g/kg bw/wk in comparison to 18 /ig/kg bw/wk for those living in non-industrial areas. Infants' lead intakes can be strongly influenced by the lead content of water, and by storage of infant formulae in lead-soldered cans. Mean intakes in excess of the PTWI were obtained in studies carried out in Germany (1980) and the UK (1981) in areas with high lead content in tap water. In a 1987 study in Canada, the lead intake by infants fed evaporated milk stored in lead-soldered cans exceeded the PTWI (Dabeka 1989). In several countries, the lowest intake is reported for infants who consume only breast milk. No trends can, as yet, be firmly established for lead intake by infants and children, except in the USA where a decreasing trend is noticeable: between 1982 and 1988, the intake of infants and children decreased from 16 to 3 jtg/kg bw/wk. Infants and Children (1980-1988)
HUN
POL
GER
UK
CAN
AUS
CUB
us
Figure 8. Average intake of lead—infants and children, 1980-1988.
Lead in food and estimated intake Lead is one of the most frequently monitored contaminants in food, with about 30 countries in the GEMS/Food network providing extensive data on concentrations in a wide variety of foods. In the monitoring programme, emphasis is placed on staple foods such as cereals and potatoes, and on foods that are most likely to contain high levels of lead (canned food, shellfish).
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804
Figure 9. Typical lead levels in food, 1980-1988.
Table 3. Estimated intake of Pb based on global diet and GEMS/Food data.
Commodity Cereals Roots and tubers Fruit Vegetables Meat Vegetable oils and fats Fish Pulses Eggs Nuts and oilseeds Shellfish Offal Spices and herbs Other foods
Global diet (g/day) 405 301 236 182 105 38 33 22 17 16 6 6 3 130
Total
1500
Drinking-water Canned beverages Canned food 3
2000 160 30
Grand total
Typical Pb levels (mg/kg)
Estimated intake (f*g/day)
0-06 0-05 0-05 0-05 0-05 0-02 0-1 0-04 0-02 0-04 0-2 0-2 0-3 n.a.
0 •02 0 •2 0 •2
% of total
24 15 12 9 5 1 3 1 0 1 1 1 1
15-9 9-9 7-7 6-0 3-4 0-5 2-2 0-6 0-2 0-4 0-8 0-8 0-6
75
48-9
40 32 6
26 •2 21 •0 3 •9
153 100 or 18 fig/kg bw/wk (PTWI = 50 pg/kg bw)
n.a. = not available. "Assumes canned food consumption 2% of total.
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Figure 9 shows that, in general, spices and herbs, canned food and beverages, are higher in lead content than cereals, fruit, meat, and vegetables. Some canned fruit juices had levels of lead greater than Codex maximum contaminant levels. Further, levels in shellfish are higher than in fish, and levels in offal are substantially higher than in meat muscle. The percent contribution of various foods to the total intake of lead, based on the global diet and typical level of lead in food, is given in table 3. The major contributors to the total intake of lead are in descending order, drinking-water, canned beverages, cereals, root and tuber vegetables, and fruit. Most of these foods have also been identified by several countries as being major contributors to lead intake. In spite of relatively high levels of lead found in shellfish, offal, spices, and canned food, their contribution to the total intake of lead is minimal in this case, because of relatively low consumption. JECFA has recommended that the major source(s) of exposure to lead be determined and all possible steps taken to ensure that lead levels in food and contributions from other environmental sources are minimized. The following major sources of lead exposure were identified by JECFA: a. lead solder and other lead-containing materials in equipment and containers coming into contact with food; b. lead contamination of drinking-water from plumbing systems; c. use of lead compounds as petrol additives; d. house paints; and e. discharge of lead into the environment by industry (WHO 1987). References ABDEL-GAWAAD, A. A., and SHAMS EL DINE, A., 1989, Insecticide residues in total diet samples. Journal of Egyptian Society of Toxicology, 4, 79-89. ANDERSEN, A., 1981, Lead, cadmium, copper and zinc in the Danish diet. Publication No. 52. (Soborg, Denmark: Miljoministeriet, Stattens Levensmiddelinstitut). DABEKA, R. W., 1989, Survey of lead, cadmium, cobalt and nickel in infant formulas and evaporated milks and estimation of dietary intakes of the elements by infants 0-12 months old. The Science of the Total Environment, 89, 279-289. FAO/WHO, 1984, Codex Alimentarius Vol. XVII—Contaminants (Rome: FAO). FOUASSIN, A., and FONDU, M., 1980, Evaluation de la teneur moyenne en plomb et en cadmium de la ration alimentaire en Belgique. Archives Beiges de Médecine Sociale, Hygiène, Médecine du Travail et Médecine Légale, 8, 453-467. GEMS/FOOD, 1982, Summary and assessment of data received from the FAO/WHO Collaborating Centres for food contamination monitoring. (Uppsala: National Food Administration). GEMS/FOOD, 1986a, Summary of 1980-1983 monitoring data (Geneva: WHO). GEMS/FOOD, 1986b, Chemical contaminants in food: 1980-1983 (Geneva: WHO). GEMS/FOOD, 1988, Summary of 1984-1985 monitoring data (Geneva: WHO). GEMS/FOOD, 1991, Summary of 1986-1988 monitoring data (Geneva: WHO). INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY, 1990, Summary of Toxicological Evaluations
Performed by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR). (Geneva: WHO). ISO, 1982, International Standards 6486/1and 6486/2. Ceramic ware in contact with foods—release of lead and cadmium—Part 1: Method of test; part 2: Permissible limits (Geneva). National Health and Medical Research Council, 1990, The 1987 market basket survey (Canberra). UNEP/FAO/WHO, 1988, Assessment of chemical contaminants in food (Nairobi). WHO, 1972, Evaluation of certain food addititives and the contaminants mercury, lead, and cadmium. Sixteenth report of the Joint FAO/WHO Export Committee on Food Additives. WHO Technical Report Series, No. 505 (Geneva: WHO). WHO, 1978, Evaluation of certain food additives and contaminants. Twenty-second report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 631 (Geneva: WHO). WHO, 1984, Guidelines for drinking-water quality (Geneva: WHO).
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WHO, 1985, Guidelines for the study of dietary intake of chemical contaminants. WHO Offset Publication, No. 87 (Geneva: WHO). WHO, 1987, Evaluation of certain food additives and contaminants. Thirtieth report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 751 (Geneva: WHO). WHO, 1989a, Evaluation of certain food additives and contaminants. Thirty-third report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 776 (Geneva: WHO); and WHO Food Additives Series: 24. Toxicological evaluation of certain food additives and contaminants (Geneva: WHO). WHO, 1989b, Guidelines for predicting dietary intake of pesticide residues (Geneva: WHO). WHO, 1989c, Minor and trace elements in breast milk. Report of a Joint WHO/IAEA Collaborative Study (Geneva: WHO).
Food Additives & Contaminants Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tfac19
Dietary intake of pesticide residues: Cadmium, mercury, and lead H. Galal‐Gorchev
a
a
International Programme on Chemical Safety , World Health Organization , Geneva, Switzerland Published online: 10 Jan 2009.
To cite this article: H. Galal‐Gorchev (1991) Dietary intake of pesticide residues: Cadmium, mercury, and lead, Food Additives & Contaminants, 8:6, 793-806, DOI: 10.1080/02652039109374038 To link to this article: http://dx.doi.org/10.1080/02652039109374038
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FOOD ADDITIVES AND CONTAMINANTS, 1991, VOL. 8, NO. 6, 7 9 3 - 8 0 6
Dietary intake of pesticide residues: cadmium, mercury, and lead H. GALAL-GORCHEV
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International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland (Received 13 August 1991; revised 1 October 1991; accepted 4 October 1991) Information on the dietary intake of chemical contaminants has been obtained from institutions participating in GEMS/Food. Contaminants studied include certain organochlorine and organophosphorous pesticides, PCBs, cadmium, mercury, and lead. The intakes are compared with toxicologically acceptable intake levels established by international expert groups. In most cases, dietary intakes of organochlorine and organophosphorous pesticides are well below the Acceptable Daily Intake (ADI) of the respective pesticide. Of some 21 countries providing information on the average dietary intake of cadmium, only in one case is the Provisional Tolerable Weekly Intake (PTWI) exceeded. Several countries identified cereals and cereal products and root and tuber vegetables as the main contributors to the dietary intake of cadmium. For mercury, all reported intakes are below the PTWI of methylmercury. The contribution of fish to the total intake of mercury varied from 20% to 85%, depending on the country. Therefore, the general assumption that fish is the main contributor to the total dietary intake of mercury may, at times, not be justified. Average dietary intake of lead exceeding or approaching the PTWI are reported for adults and infants and children in some countries. Foodstuffs which contribute most to the intake of lead vary from country to country, and have been identified as being alternately drinking water, beverages, cereals, vegetables and fruit. Keywords: dietary intake, pesticide residues, cadmium, mercury, lead
Introduction
The Joint UNEP/FAO/WHO Food Contamination Monitoring Programme, or GEMS/Food, is a component of the Global Environment Monitoring System (GEMS) established by the United Nations Environment Programme. The major objective of the Programme is to collect, assess, and disseminate information on levels and trends of contaminants in food, the magnitude of dietary exposure and the significance with regard to public health. At present 39 countries participate in GEMS/Food, and through the active collaboration of these countries, information has been obtained on levels and trends of chemical contaminants in food and magnitude of dietary exposure. Information on the dietary intake of contaminants is of special health interest since by comparison with acceptable or tolerable intake levels, a determination can be made as to whether or not consumers are likely to be at risk. In order to encourage international cooperation in such exposure studies, Guidelines for the Study of Dietary Intake of Chemical Contaminants have been published (WHO 1985). The Guidelines provide a detailed description of procedures and methods by which dietary intake studies may be conducted and have encouraged several 0265-203X/91 $3.00 © 1991 Taylor & Francis Ltd.
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countries to conduct such studies, and to make available the information to GEMS/Food. Such dietary exposure assessment will enable national health authorities to make sound decisions in the regulation of chemical contaminants in food, and thus ensure the safety of the food supply with respect to these substances. Since 1980, information on contaminants in total diets has been collected by GEMS/Food. Summary reports of these data have been issued (GEMS/Food 1986a, 1988, 1991) and periodic assessment of the data carried out (GEMS/Food 1982, 1986b, UNEP/FAO/WHO 1988). Information recorded includes the mean, median and 90th percentile values. However, most countries provide information on the mean intake only. The composition of the diet, preparation for analysis, total weight of the diet and study approach vary widely from country to country. For instance, the amount of food consumed may be purposely exaggerated (3 • 3 kg/day) in order to protect extreme consumers; drinking water and alcoholic beverages may or may not be included in the diet; foods may not be cooked prior to analysis; the number of foods analysed can vary from 10 to over 100; and finally, the methodology used in estimating the daily intake of a contaminant varies from country to country. Because of such differences, while trends within a country may at times be established, comparisons between countries should be done with caution. Three basic approaches can be used to determine intake (WHO 1985): (a) Total diet (i.e. market basket) studies. The sample for this type of study consists of a market basket of food reflecting a defined total diet of a consumer for a specific period of time. The foods are prepared for table-ready consumption and are analysed either individually or combined in one or more food-group composites (e.g. cereals, meat, root vegetables, etc.) in proportions based on available consumption data. Residue levels measured in the total diet samples are used in calculating the average daily intake for each composite and for the diet as a whole. A total diet study is particularly valuable in initially determining whether residues are widely distributed among all the broad classes of major foods, or are confined to a few general classes of foods, e.g. fruit, vegetables. (b) Selective studies of individual foodstuffs. This approach involves measurement of residue levels in representative samples of staple foods, either raw or cooked, which, together with food consumption data, enables average daily intakes to be calculated. Such an approach is particularly useful if the intake of a contaminant is predominantly influenced by one or two commodities and/or when food contamination monitoring programmes have established average residue levels in the commodities. In combination with food consumption surveys, it is possible to obtain a reasonable assessment of exposure in selected consumer groups. (c) Duplicate portion studies. Representative diets of individuals can be collected over a period of days by requesting that institutions or an individual provide, for residue analysis, a duplicate sample of the meals consumed. Such an approach has been successfully used in residue intake studies in well-defined populations. Depending on the objectives of the assessment and the resources available, all three approaches have been used by countries participating in GEMS/Food. Organochlorine compounds Available information on the average intake by adults of various organochlorine pesticides and PCBs are given in table 1. The intakes are reported
Dietary intake of chemical contaminants
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Table 1. Mean dietary intake, % of ADI (adults, most recent year). Country (year of study) ADI Australia Egypt Finland Guatemala Japan New Zealand Thailand UK USA Compound (;ug/kg bw) (1987) (1988) (1986) (1988) (1988) (1982) (1987) (1985) (1988)
Aldrin/ dieldrin
0-1 20 6 0-2 0-5 8
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DDT
Endosulfan Endrin Heptachlor Lindane HCB b HCH b PCBsb
7-0 a 0-l a l-4 a l-0 a
1364 0-1
68
1194 125
0-03 0-03
ND
7-8 0-2 1-6 0-9 0-4
3-0 0-1
0-02
0-02 ND 0-01 0-04
ND ND
0-01
ND
0-04
7-1
0-01
ND
0-04 0-07
3-9 0-4
0-03 0-2
0-8
0-09 0-01 ND
0-03
ND ND ND
a
95th percentile consumer. No ADI established, intakes in jjg/kg bw/day. ND = Not Detected. b
as percentages of the respective acceptable daily intake (ADI) established by the Joint FAO/WHO Meeting on Pesticide Residues (IPCS 1990). In Egypt, the intakes of aldrin/dieldrin and endrin are about ten times the ADI; in the case of lindane and DDT, the intake was 125% and 68% of the ADI, respectively (Abdel-Gawaad and Shams El Dine 1989). The high intake of organochlorine pesticides in Egypt warrants further investigation. For the other countries, mean intakes in recent years are all below 10% of the respective ADIs and in most cases the intakes are less than 1 % of the ADI. Australia and the USA provided information on the dietary intake of the adult population as well as various other population groups such as infants, 2-year old Adults 26 2422201816 ^ 14 12 S
108 64 2 0
1—
1980
1981
1983
1982 D
Japan
1984
1985 A
1986
1987
USA
Figure 1. Mean intake of aldrin and dieldrin—adults.
—I 1988
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H. Galal-Gorchev
children, boys and girls aged 14-16 years, etc. In the USA, intakes of organochlorine pesticides by the 6-11-month old infant, and the 2-year old child are in many cases 2-4 times that of an adult on a kg/bw basis. In the case of Australia, no clear trend could be seen between the intake of various population groups. For countries reporting intakes over several years, a downtrend is noticeable as shown in figure 1 for the intake of aldrin/dieldrin in Japan and the USA.
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Organophosphorus pesticides
In the case of the organophosphorus pesticides, diazinon, fenitrothion, malathion, methyl parathion and parathion, mean intakes reported by Guatemala, Japan, New Zealand, Thailand and the USA are below l°7o of the respective ADIs, and in the majority of cases these compounds were not detected in total diet studies. The only exception was in the case of Australia which reported an intake of fenitrothion by the 95th percentile consumer of about 50% of the ADI, and recommended that the significance of this finding be assessed by the authorities concerned (NHMRC 1990). Cadmium
International recommendations In 1988, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established a Provisional Tolerable Weekly Intake (PTWI) of cadmium from all sources of 7 /tg/kg bw, applicable to adults as well as infants and children. The PTWI from all sources was derived from estimated accumulation over a period of 50 years at an exposure rate equivalent to 1 fig/kg bw for adults; excursions above this figure may therefore be tolerated provided that they are not sustained for long periods of time. In addition, JECFA estimated the dietary intake of cadmium to be usually 1-4 /tg/kg bw/wk, and recognized that '...there is only a relatively small safety margin between exposure in the normal diet and exposure that produced deleterious effects.' Consequently, JECFA recommended that levels of cadmium in foods and total diet should continue to be monitored, and should not increase further (WHO 1989a). A guideline value of 0-005 mg/litre has been recommended for cadmium in drinking-water (WHO 1984). This value is at present under review. The International Organization for Standardization established maximum limits for the release of cadmium from ceramic ware of 0-17mg/dm2 for flatware and 0-25-0-50 mg/litre of extraction solution for hollow-ware (ISO 1982). Dietary intake of cadmium Average adult intake in different countries for the most recent year provided (over the period 1981-88) are presented in figure 2. With the exception of Thailand, all reported intakes are below the PTWI of 7 /tg/kg bw for cadmium. No particular time trend in intake was noticeable for those countries providing information over several years. Canada, Denmark, Finland, The Netherlands, and the USA identified cereals and their products, followed by potatoes and other vegetables, as the largest contributors to such intake. Fruit, meat, poultry, and dairy products contributed little to the intake.
Dietary intake of chemical contaminants
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Adults, 1981-1988
THA NZE POL GUA FRA ITA JPN AUS NET GER CUB UK BEL DEN SWI CAN SWE FIN USA TUR HUN
Figure 2. Average intake of cadmium—adults, 1981-1988.
High cadmium levels are found in animal kidney and shellfish. In Belgium, it was noted that once-a-week consumption of mussels or kidney would result in a mean intake that would approximate the PTWI (Fouassin and Fondu 1980). Similarly, in Denmark (Andersen 1981) above average consumption of beef kidney, mussels from contaminated water, or wild mushrooms, yield intakes that exceed the PTWI. In Poland, intake of cadmium by populations living in industrial areas was about double that of populations in non-industrial areas. Several countries provided information on intakes of cadmium by infants and children (Australia, Canada, Cuba, Germany, Hungary, Poland, Sweden, UK and USA). Intakes on a kg/bw basis for infants and children of varying ages are higher than those of the adult population in these same countries. However, none of these intakes exceed the PTWI. In Sweden, the intake of cadmium by exclusively breastfed infants is appreciably less than that of adults, indicating the low level of contamination of human milk by cadmium. The average dietary intake of cadmium by Canadian infants who were given milk-based formula or human milk amounted to 3 fig/kg bw/wk. Feeding infants soya-based formula increased the intake to 5 fig/kg bw/wk (Dabeka 1989). Cadmium in food and estimated intake Some 20 institutions participating in GEMS/Food provided information on the concentration of cadmium in food. Typical cadmium levels in various foods are given in figure 3. Levels in dairy milk and products, eggs, fats and oils, nuts, and human milk, were usually at or below the limits of detection. High levels of cadmium are found in kidneys and shellfish, with extremely high levels found at times in lobster and crab bodies. Most fish species, cereals, root and tuber vegetables, as well as other vegetables, contain relatively low cadmium levels. Monitoring data on average contaminant levels in food, together with food consumption data, can be used to obtain rough estimates of intakes. In the absence
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350
Offal
Shellfish
Cereals
Roots
Fish
Figure 3. Typical cadmium levels in food, 1980-1988.
of dietary intake studies, this approach can be used to make a preliminary assessment of likely dietary exposure and to tentatively identify foods that are major contributors to the intake. GEMS/Food survey data, together with a hypothetical 'global' diet, are used in table 2 to illustrate such an approach. The global diet, which is representative of an 'average' adult, is based on FAO Food Balance Sheets, and has been developed following the recommendations of the Joint FAO/WHO Consultation on Guidelines for Predicting Dietary Intake of Pesticide Residues. It is being used to predict intake of pesticide residues (WHO 1989b). This global diet is obtained from the highest average food consumption Table 2. Estimated intake of Cd based on global diet and GEMS/Food data.
Commodity Cereals Roots and tubers Fruit Vegetables Meat Fish Shellfish Offal Other foods Total
Global diet (g/day)
Typical Cd levels (mg/kg)
Estimated intake (fg/day)
405 301 236 182 105 33 6 6 226
0-03 0-02 0-003 0-009 0-006 0-02 0-2 0-3 0-002
12-2 6-0 0-7 1-6 0-6 0-7 1-2 1-8 0-5
1500
% of total intake 48 24 3 6 2 3 5 7 2
100 25 or 3 (ig/kg bw/wk (PTWI = 7 /ig/kg bw)
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Dietary intake of chemical contaminants
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values from five regional diets and normalizing to a total daily consumption of 1-5 kg of solid food, i.e. excluding the liquid content of juices or milk. Better intake estimates can, of course, be obtained where national monitoring and food consumption data are used. The percent contribution of various foods to the total intake of cadmium, based on the global diet and typical levels of cadmium in food, are given in table 2. Relatively low levels of cadmium are found in cereals and root and tuber vegetables; nevertheless, concording with the information provided by several countries, these foodstuffs, because of their high consumption, contribute most to the total intake. Offal and shellfish contribute a total of about 10% to the overall intake of cadmium. Steps aimed at reducing the concentration of cadmium in cereals and root and tuber vegetables, the main contributors to the total intake, would be most effective in avoiding an increase in cadmium intake. JECFA identified several sources of contamination of food by cadmium: phosphate fertilizers and sewage sludge used on agricultural land, use of cadmiumplated utensils and galvanized equipment in food processing and preparation, leachable cadmium in enamel and pottery glazes and cadmium-based pigments or stabilizers used in food-contact plastics (WHO 1989a). Effective control of such sources would avoid increases in levels of cadmium in foods and total diet. Mercury International recommendations JECFA established a PTWI of 300 fig of total mercury per person, of which no more than 200 ^g should be present as methylmercury. These amounts are equivalent to 5 ^g/kg bw and 3-3 /*g/kg bw respectively (WHO 1972). In 1988, the Committee re-assessed methylmercury as new data were only then available for this compound, and confirmed the previously recommended PTWI of 200 ng of methylmercury (3-3 /ig/kg bw) for the general population, but noted that pregnant women and nursing mothers are likely to be at greater risk from the adverse effects of methylmercury. The available data were considered insufficient to recommend a specific methylmercury intake for this population group (WHO 1989a). A guideline value of 0*001 mg/litre has been recommended for mercury in drinking-water (WHO 1984). Dietary intake of mercury Adults. Dietary intakes for the most recent year provided by countries (between 1981 and 1988) are given in figure 4. All intakes are below the PTWI of methylmercury of 3-3 ftg/kg bw. The contribution of fish to the total dietary intake of mercury varies from a low of 20% in Belgium, Germany, and The Netherlands, to a high of 85% in Finland and the USA, with France and the UK in between (35%). The Netherlands provided information on levels of mercury in different foods: higher concentration of mercury is found in fish (about 0-1 mg/kg) than in other foods (0'01 mg/kg or less). However, because of higher consumption, the contributions of food groups such as cereals and meat to the total intake were about the same as that from fish. Therefore, the general assumption that fish is the main contributor to the total dietary intake of mercury may, at times, not be justified.
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Adults, 1981-1988
9
I
GER
BEL
GUA
DEN
ITA
NET
THA
NZE
SWE
UK
USA
AUS
FIN
Figure 4. Average intake of mercury—adults, 1981-1988.
Infants. The dietary intakes of mercury by exclusively breast-fed 3-month old infants are given in figure 5 for Sweden, Nigeria, Zaire, the Philippines, Guatemala and Hungary (WHO 1989c). For comparison purposes, the USA reported a 1988 weekly intake by a 6-11-month old infant of 0-4 jig/kg bw. The Swedish value is significantly higher than those for other study areas. 'It is possible that this increased mercury content of human milk be related to the fact that much fish is consumed in the country, but this requires further investigation.' (WHO 1989c). Breast-fed infants
Sweden
Nigeria
Zaire
Philippines
Guatemala
Figure 5. Median intake of mercury—breast-fed infants.
Hungary
Dietary intake of chemical contaminants
801
Mercury in fish and estimated intake Typical levels reported to GEMS/Food for total mercury in fish were in the vicinity of 0-2mg/kg. Inadequate data are available to GEMS/Food on levels of mercury in food other than fish. The 'global' consumption of fish and shellfish is 40 g/day. Assuming a level of methylmercury of 0*2 mg/kg, the estimated weekly intake is about 1 /tg/kg bw in comparison to the PTWI of 3 -3 /xgjkg bw for methylmercury. This estimated intake does not take into account possible exposure from food other than fish.
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Lead International recommendations In 1972, JECFA established a PTWI of lead of 50/ig/kg bw, applicable to adults only (WHO 1972); this PTWI was reconfirmed in 1978 (WHO 1978). Because of the special concern for infants and children, JECFA later evaluated the health risks of lead to this group and established a PTWI of 25 /ig/kg bw. This level refers to lead from all sources (WHO 1987). A guideline value of 0-05 mg/litre has been recommended for lead in drinkingwater (WHO 1984). This value is at present under review. Within the Joint FAO/WHO Food Standards Programme, maximum levels of 0-2 mg/kg to 2>0 mg/kg have been established for lead in a number of foods such as sugars, cocoa products, and fruit juices (FAO/WHO 1984). The International Organization for Standardization established maximum limits for the release of lead from ceramic ware of W m g / d m 2 for flatware and 2-5-5-0 mg/litre of extraction solution for hollow-ware (ISO 1982). Dietary intake of lead Adults. Information on the most recent intake of lead by adults in different countries is given in figure 6. Intakes slightly exceeding or approaching the PTWI are reported for the average adult in Cuba (1984), Italy (1982) and Thailand (1987). The lowest intake is reported by the USA (1988). There are thus considerable differences in lead intakes reported from different countries. Whether these differences are real or partly due to factors associated with the study approach, remains to be assessed. Inadequacies in analytical quality control may also account for some of the differences. In a 1987 study in Australia (NHMRC 1990), lead intake of the 95th percentile consumer was approximately four times the intake of the average consumer. Intake of the average person in a country if approaching the PTWI, should be viewed with some concern since a certain segment of the population, because of varying dietary habits, may exceed the PTWI. Increases in lead intake were noted in some countries with consumption of wine, for populations living in industrial areas and in areas where lead concentrations in tap water are higher than average. Some countries have provide dietary intake information to GEMS/Food over several years. Trends in lead intake are shown for some countries in figure 7. It appears that a downward trend in lead intake has taken place in the UK and the USA. The decreasing trend in the USA coincides, in the early 1980s, with a reduction in the use of lead-soldered cans, and also in the lead content of petrol.
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Adults, 1981-1988
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60-
Cub
Ita Tha Gua HZ
Bel Fra Pol Ire Ger Hun Jpn UK Tur Can Net Den AUS Swi Swe Fin US
Figure 6. Average intake of lead—adults, 1981-1988.
Foodstuffs which contribute most to the total intake of lead by adults vary from country to country, and have been identified as being alternatively drinkingwater, beverages, cereals, vegetables and fruit. In spite of high levels of lead that may be found in canned food, these foods, because of their relatively low consumption, were not identified as major contributors to the intake.
1988
D
USA
o
Japan
a
Hungary
Figure 7. Trends in lead intake by adults.
803
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Dietary intake of chemical contaminants
Infants and children. Relatively few countries report dietary intake of lead by infants and children. The intake by infants and children up to 12 years of age are given in figure 8. Since the PTWI of lead for infants and young children refers to the maximum intake from all sources (food, water, air, dust, etc.) the average intake from food should be well below the PTWI of 25 /*g/kg bw to allow for exposure from other media (WHO 1987). In Hungary (1983), in a children's home, intake of 3-6-year olds was about double the PTWI, while for breast-fed infants, the intake amounted to half the PTWI. Intake greater than the PTWI was reported in Poland (1985) and Germany (1980). In a 1984 study in Poland, the intake of children living in industrial areas amounted to 35 ^g/kg bw/wk in comparison to 18 /ig/kg bw/wk for those living in non-industrial areas. Infants' lead intakes can be strongly influenced by the lead content of water, and by storage of infant formulae in lead-soldered cans. Mean intakes in excess of the PTWI were obtained in studies carried out in Germany (1980) and the UK (1981) in areas with high lead content in tap water. In a 1987 study in Canada, the lead intake by infants fed evaporated milk stored in lead-soldered cans exceeded the PTWI (Dabeka 1989). In several countries, the lowest intake is reported for infants who consume only breast milk. No trends can, as yet, be firmly established for lead intake by infants and children, except in the USA where a decreasing trend is noticeable: between 1982 and 1988, the intake of infants and children decreased from 16 to 3 jtg/kg bw/wk. Infants and Children (1980-1988)
HUN
POL
GER
UK
CAN
AUS
CUB
us
Figure 8. Average intake of lead—infants and children, 1980-1988.
Lead in food and estimated intake Lead is one of the most frequently monitored contaminants in food, with about 30 countries in the GEMS/Food network providing extensive data on concentrations in a wide variety of foods. In the monitoring programme, emphasis is placed on staple foods such as cereals and potatoes, and on foods that are most likely to contain high levels of lead (canned food, shellfish).
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804
Figure 9. Typical lead levels in food, 1980-1988.
Table 3. Estimated intake of Pb based on global diet and GEMS/Food data.
Commodity Cereals Roots and tubers Fruit Vegetables Meat Vegetable oils and fats Fish Pulses Eggs Nuts and oilseeds Shellfish Offal Spices and herbs Other foods
Global diet (g/day) 405 301 236 182 105 38 33 22 17 16 6 6 3 130
Total
1500
Drinking-water Canned beverages Canned food 3
2000 160 30
Grand total
Typical Pb levels (mg/kg)
Estimated intake (f*g/day)
0-06 0-05 0-05 0-05 0-05 0-02 0-1 0-04 0-02 0-04 0-2 0-2 0-3 n.a.
0 •02 0 •2 0 •2
% of total
24 15 12 9 5 1 3 1 0 1 1 1 1
15-9 9-9 7-7 6-0 3-4 0-5 2-2 0-6 0-2 0-4 0-8 0-8 0-6
75
48-9
40 32 6
26 •2 21 •0 3 •9
153 100 or 18 fig/kg bw/wk (PTWI = 50 pg/kg bw)
n.a. = not available. "Assumes canned food consumption 2% of total.
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Dietary intake of chemical contaminants
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Figure 9 shows that, in general, spices and herbs, canned food and beverages, are higher in lead content than cereals, fruit, meat, and vegetables. Some canned fruit juices had levels of lead greater than Codex maximum contaminant levels. Further, levels in shellfish are higher than in fish, and levels in offal are substantially higher than in meat muscle. The percent contribution of various foods to the total intake of lead, based on the global diet and typical level of lead in food, is given in table 3. The major contributors to the total intake of lead are in descending order, drinking-water, canned beverages, cereals, root and tuber vegetables, and fruit. Most of these foods have also been identified by several countries as being major contributors to lead intake. In spite of relatively high levels of lead found in shellfish, offal, spices, and canned food, their contribution to the total intake of lead is minimal in this case, because of relatively low consumption. JECFA has recommended that the major source(s) of exposure to lead be determined and all possible steps taken to ensure that lead levels in food and contributions from other environmental sources are minimized. The following major sources of lead exposure were identified by JECFA: a. lead solder and other lead-containing materials in equipment and containers coming into contact with food; b. lead contamination of drinking-water from plumbing systems; c. use of lead compounds as petrol additives; d. house paints; and e. discharge of lead into the environment by industry (WHO 1987). References ABDEL-GAWAAD, A. A., and SHAMS EL DINE, A., 1989, Insecticide residues in total diet samples. Journal of Egyptian Society of Toxicology, 4, 79-89. ANDERSEN, A., 1981, Lead, cadmium, copper and zinc in the Danish diet. Publication No. 52. (Soborg, Denmark: Miljoministeriet, Stattens Levensmiddelinstitut). DABEKA, R. W., 1989, Survey of lead, cadmium, cobalt and nickel in infant formulas and evaporated milks and estimation of dietary intakes of the elements by infants 0-12 months old. The Science of the Total Environment, 89, 279-289. FAO/WHO, 1984, Codex Alimentarius Vol. XVII—Contaminants (Rome: FAO). FOUASSIN, A., and FONDU, M., 1980, Evaluation de la teneur moyenne en plomb et en cadmium de la ration alimentaire en Belgique. Archives Beiges de Médecine Sociale, Hygiène, Médecine du Travail et Médecine Légale, 8, 453-467. GEMS/FOOD, 1982, Summary and assessment of data received from the FAO/WHO Collaborating Centres for food contamination monitoring. (Uppsala: National Food Administration). GEMS/FOOD, 1986a, Summary of 1980-1983 monitoring data (Geneva: WHO). GEMS/FOOD, 1986b, Chemical contaminants in food: 1980-1983 (Geneva: WHO). GEMS/FOOD, 1988, Summary of 1984-1985 monitoring data (Geneva: WHO). GEMS/FOOD, 1991, Summary of 1986-1988 monitoring data (Geneva: WHO). INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY, 1990, Summary of Toxicological Evaluations
Performed by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR). (Geneva: WHO). ISO, 1982, International Standards 6486/1and 6486/2. Ceramic ware in contact with foods—release of lead and cadmium—Part 1: Method of test; part 2: Permissible limits (Geneva). National Health and Medical Research Council, 1990, The 1987 market basket survey (Canberra). UNEP/FAO/WHO, 1988, Assessment of chemical contaminants in food (Nairobi). WHO, 1972, Evaluation of certain food addititives and the contaminants mercury, lead, and cadmium. Sixteenth report of the Joint FAO/WHO Export Committee on Food Additives. WHO Technical Report Series, No. 505 (Geneva: WHO). WHO, 1978, Evaluation of certain food additives and contaminants. Twenty-second report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 631 (Geneva: WHO). WHO, 1984, Guidelines for drinking-water quality (Geneva: WHO).
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WHO, 1985, Guidelines for the study of dietary intake of chemical contaminants. WHO Offset Publication, No. 87 (Geneva: WHO). WHO, 1987, Evaluation of certain food additives and contaminants. Thirtieth report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 751 (Geneva: WHO). WHO, 1989a, Evaluation of certain food additives and contaminants. Thirty-third report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Technical Report Series, No. 776 (Geneva: WHO); and WHO Food Additives Series: 24. Toxicological evaluation of certain food additives and contaminants (Geneva: WHO). WHO, 1989b, Guidelines for predicting dietary intake of pesticide residues (Geneva: WHO). WHO, 1989c, Minor and trace elements in breast milk. Report of a Joint WHO/IAEA Collaborative Study (Geneva: WHO).
