Dietary intake estimations of organohalogen contaminants (dioxins, PCB, PBDE and chlorinated pesticides, e.g. DDT) based on Swedish market basket data

Food and Chemical Toxicology 44 (2006) 1597–1606 www.elsevier.com/locate/foodchemtox

Dietary intake estimations of organohalogen contaminants (dioxins, PCB, PBDE and chlorinated pesticides, e.g. DDT) based on Swedish market basket data P.O. Darnerud *, S. Atuma, M. Aune, R. Bjerselius, A. Glynn, K. Petersson Grawe´, W. Becker Toxicology Division, National Food Administration, P.O. Box 622, SE-751 26 Uppsala, Sweden Received 1 July 2005; accepted 24 March 2006

Abstract By use of a Swedish Market basket study from 1999, in which foods were sampled from four regions, the dietary intake of persistent organic pollutants (POPs) was assessed. Based on earlier data, six food groups (fish, meat, dairy products, egg, fats/oils, and pastries; comprising 52 food items) were selected for POP analyses. Homogenates were subjected P from these six groups P P to POP analyses P and levels presented on dioxins (PCDD/PCDFs), dioxin-like PCBs, PCB-153, PCBs, BDE-47, PBDEs, DDE, DDTs, HCB, HCHs, and P chlordanes, after adjusting non-quantified levels to 1/2 LOQ. For all compounds, the fish homogenate contained the comparatively P P highest levels, on a fresh weight basis. Intake calculations based P on the six food groups showed that PCBs and DDTs gave per capita intakes of 615 and 523 ng/day, respectively, that the estimated PBDE intake was 51 ng/day and that of dioxins and P dioxin-like PCBs was 96 pg WHO–TEQ/day. The estimated mean intakes were below (total-TEQ: 1.3 pg/kgbw/day) or well below ( DDTs: 8.9 ng/ P kgbw/day) internationally agreed intake limits (total-TEQ: 2 pg/kgbw/day; DDTs: 10 000 ng/kgbw/day). A number of uncertainty factors, including analytical limitations dueP to low POPP levels in food, give reason for caution in the use of the presented intake data. However, the intake estimations of dioxins, PCBs and PBDEs are well in accordance to calculations of POP intakes in Sweden made by alternate methods. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Food consumption; Persistent organic pollutants (POPs); Intake estimation; Sweden

1. Introduction In most cases, dietary intake of persistent organic pollutants (POPs) is the major source in the total human exposure to these compounds. For example, the food intake of dioxins is estimated to account for at least 90% of the total exposure (Liem et al., 2000). Consequently, in cases where the actual exposure is close to or above the tolerable daily intake (TDI), the presence of POPs in food constitutes a potential health problem. Depending on national or regional food habits and traditions, the actual intake of POPs, and the relative intake from different food groups, may *

Corresponding author. Tel.: +46 18 171452; fax: +46 18 105848. E-mail address: [email protected] (P.O. Darnerud).

0278-6915/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.fct.2006.03.011

vary considerably. Fat-rich food items contain more than lean products, but there are considerable differences in occurrence levels between food groups also when fat weight-based data are compared. Food of animal origin contains the highest levels of most POPs, and these groups will constitute the major contributors to the POP intake. For instance, in the Nordic countries the intake of fish is of major importance for the total intake of POPs, and recent Swedish and Finnish estimations show that 70– 80% of the PCB intake originates from consumption of fish (Lind et al., 2002; Kiviranta et al., 2004). On the other hand, studies from Finland and Holland show that vegetables constitute only a small part of the total dioxin (PCDD/ DFs + dioxin-like PCBs) intake from food (Kiviranta et al., 2001; Patandin et al., 1999; Freijer et al., 2001).

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In Sweden polychlorinated biphenyl (PCB) and dioxin (PCDD/PCDF) intakes have earlier been calculated on the basis on the levels in food of animal origin from the early 1990s using per capita consumption data from the Swedish Board of Agriculture (Darnerud et al., 1995; Wicklund Glynn et al., 1996). A more recent estimation of the intake of several POPs including polychlorinated biphenyls (PCBs), dioxins, DDT, polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD) (Lind et al., 2002), based on the Swedish food consumption survey Riksmaten 1997–1998 (NFA, 2002), indicated lower intakes of PCBs and dioxins than those reported 1995– 1996. As there has lasted a time period of about 10 years between collections of food samples for the two studies, the reason for a lower estimated intake in the recent study could be a general decrease in POP levels in food. However, the result may also be influenced by a changed pattern of food consumption or differences related to the study design and procedures. In the compilation of available dioxin intake estimations from 10 EU member states, including Sweden and the other Nordic countries, the average intakes seemed to be rather similar (e.g. SCOOP, 2000). However, the relative contribution from different food groups varies a great deal between the countries and for example is fish consumption far more important for Sweden, Finland and Norway than for more southern EU countries. Examples of recent studies on POP intake from non-Nordic EU countries are those on dioxins and PCB (Holland – Baars et al., 2004; Spain – Llobet et al., 2003a) and polybrominated diphenyl ethers (PBDEs) (Spain – Domingo, 2004; UK – Harrad et al., 2004). A market basket-based estimation of the average intake of POPs in food has earlier been performed in Sweden. In a study from 1994, a Swedish market basket survey was performed with the main purpose to analyse the levels of radioactive cesium from the Chernobyl accident (Mo¨re et al., 1995). In the same study the intake of several POPs has been estimated in two food groups, representing liquid and solid food of animal P origin. These P approximate estimations of PCB, HCB, HCHs, and DDT have not earlier been published but will now be discussed in connection to the present study. The aim of the present study was to estimate the mean Swedish per capita intake of selected POPs derived from background contamination, to compare the result with other recent intake estimations made by alternative methods and with an earlier Swedish market basket study in 1994. Intake estimations of the actual compounds will be used in risk assessments for Swedish consumers. In the present study, the analysed food groups were selected on the basis of earlier data showing that food of animal origin, especially fatty food, may contain elevated levels of POPs. Thus, of the collected food items belonging to 15 food groups, six groups (fish/fish products, meat/meat products, dairy products, eggs, fats and oils, and pastries) were used for POP analyses, as a basis for intake estimations.

2. Materials and methods 2.1. Sampling The basis for sampling was the per capita consumption data, derived from Swedish producers and trade statistics (SBA, 1999). Thus, 123 selected food products, representing food categories consumed at minimum 0.5 kg per person and year, were obtained in 1999 at two places of purchase in each of four major Swedish cities, namely Malmoe (Malmo¨), Gothenburg (Go¨teborg), Uppsala and Sundsvall (i.e. eight purchase places totally). The towns are geographically well separated in different regions of Sweden and represent major population areas (Fig. 1). The food items were divided into 15 food groups, for example fish/fish products, meat/ meat products, cereals, etc. (Table 1). Some of the food items, e.g. butter, could be found as more or less identical products/brands from all the sampling towns, whereas other food samples, e.g. fresh fish, to some extent represent the local/regional consumption. At least one unit/package of every listed food item was sampled from each shop. For practical reasons, ice cream and the alcohol-containing beverages (the latter sold only in

Fig. 1. Sampling locations in the present market basket study.

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Table 1 Description of food items (and their matching food groups) sampled in Swedish market baskets (n = 8), purchased in four different cities in Sweden 1999 Food group

1% of annual average consumption, g

No. of food items

Description Milk, sour milk, yoghurt, cream, hard cheese, processed cheese, cottage cheese Beef, pork, lamb, poultry, cured/processed meats Butter, margarine, cooking oil, mayonnaise Biscuits, buns, cakes Fresh and frozen, canned products, shellfish

Dairy products

1685

12

Meat products Fats Pastries Fish Egg Cereal products

567 175 137 133 92 694

16 6 4 13 1 11

548 641 514 286 1188 145/218 28 68

19 15 4 6 4 7 3 2

Vegetables, including root vegetables Fruit Potatoes Sugar and sweets Soft drinks, lemonade, beer (2.1–3.5% alcohol) Wine/strong beer (>5% alcohol) Spirits Ice cream

Flour, grain, corn flakes, pasta, bread including wholemeal bread Fresh and frozen, canned products Fresh and frozen, canned products, juice, nuts Fresh, French fried Sugar, chocolate, sugar sweets, sauces Soft drinks, mineral water, light lager, medium-strong beer

The food groups in bold letters (n = 6) have been used in analyses of POP compounds in the present study.

monopoly shops) were obtained only in Uppsala. However, these products are identical all over the country. Based on consumption statistics (SBA, 1999) the yearly consumption of the listed food items was obtained (summarised in Table 1). The complete list represents practically all major single food items or food groups for which the per capita consumption is above 0.5 kg/year, i.e. 1.5 g per day. Thus, the market basket food list will cover approximately 90% of the food supply available for consumption. The market basket study covers several fields of interests, and nutrients as well as food contaminants are studied in various homogenate samples of the overall study. As regards the POP analyses, six of the 15 food groups were chosen. These were fish and fish products, meat and meat products, dairy products, egg, fats and oils, and sweet bakery products (pastries), totally comprising 52 food items. The reason for choosing these groups were earlier data showing that food of animal origin contribute with the major part of the POP intake from food, and that the vegetable food groups generally contain low levels of these compounds and will add little to the total intake (e.g. Kiviranta et al., 2001; Freijer et al., 2001). However, vegetable fats and oils were included in the fats/oil group, as the POPs will primarily be found in the fatty part of the food, if they are at all present. Also, pastries were included in the analyses based on the assumption that marine oils could be used as ingredients of bakery margarines or shortenings.

2.2. Sample preparation From each food unit/package, one percent (by weight) of the yearly per capita consumption was taken out for homogenate preparation and subsequent analysis. In case of food items where wastage could be supposed, inedible parts such as bone, skin, etc. were removed prior to homogenisation. The weighed amount of food samples from every food item within a food group (e.g. meat/meat products) were subsequently mixed and carefully blended (by use of a household mixer). For economical reasons, the two food group-specific homogenates from each town were mixed (1:1 by weight) before analysis to bring down the number of analyses. From these homogenates, samples were taken for analyses of the selected POP compounds.

performed. Generally, in case of occurrence levels below the limit of quantification (LOQ), half the LOQ was used. Apart from the dioxins and the coplanar PCBs, all analyses were carried out at the National Food Administration in Uppsala (NFA) by high-resolution gas chromatography using a dual capillary column system with dual electron-capture detection (Atuma et al., 1996; Atuma and Aune, 1999; Lind et al., 2003). Blank samples were included in every batch of samples to check for possible contamination. The analytical results were not corrected for the blank samples. The coefficient of variation was less than 20% for the compounds analysed. The laboratory at NFA regularly participates in international inter-laboratory trials of the compounds of interest to validate the analytical methods. The laboratory was accredited according to ISO 17025 for the analysis of organochlorine compounds in meat and fat tissue at the time these analyses were made. 2.3.1. Dioxins and dioxin-like PCBs Seventeen PCDD/DF congeners and three coplanar PCB congeners (PCB 77, 126, 169) were analysed by isotope dilution technique by highresolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) at Dr. Wessling Laboratorien GmbH, Altenberge, Germany. Blank and control samples were included in every batch of samples. The analytical results were not corrected for the blank samples. Additional six PCB congeners with TEF factors (PCB 105, 114, 118, 156, 157, 167) were analysed at NFA. The obtained TEQ values, according to the TEFs recommended by WHO (Van den Berg et al., 1998), were based on 17 PCDD/DF and 9 PCB congeners. The three additional dioxin-like PCB congeners with TEF factors that were not included in our analyses (PCB 81, 123 and 189) contribute very little to the total PCB– TEQ values (1–2% based on calculations on salmon and herring samples). 2.3.2. P PBDEs PBDE values are based on analyses of the five PBDE congeners BDE 47, 99, 100, 153 och 154. 2.3.3. PCBs P The PCB values are based on analyses of the PCB congeners 28, 31, 52, 66, 74, 77, 101, 105, 110, 114, 118, 126, 128, 138, 149, 153, 156, 157, 158, 167, 169, 170 and 180 (23 congeners).

2.3. Analysis In the present study analyses on dioxins, PCB, PBDE, and chlorinated pesticides (including DDT, HCB, HCHs, and chlordanes) have been

2.3.4. DDTs P The DDT values are based on analyses of p,p 0 -DDE, p,p 0 -DDD, 0 p,p -DDT and o,p 0 -DDT.

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2.3.5. Other chlorinated pesticides P Analyses were performed on HCB, HCHs ( HCHs based on analyses P of the isomers alfa-, beta- and gamma-HCH), and chlordanes ( chlordane based on analyses of oxy-chlordane, alfa-chlordane, gamma-chlordane, and trans-nonachlor).

2.4. Market basket-derived intake estimation On the basis of the analyses, and if necessary extrapolating nonquantified levels with half the quantification levels (
3. Results The sampled food items, presented in Table 1, constitute the base for homogenates used in the POP analyses. Within each food group, a number of common food items were specified (not shown in the table), and e.g. in the meat group 16 different food items were bought on the market. In Table 2 occurrence values (city specific and mean of four) in food homogenates are shown for dioxin/PCB– TEQs, PCBs, PBDEs (in Table 2a), and DDTs, HCB, P P HCHs, and chlordanes (in Table 2b). These results are given on product (fresh weight) basis in order to be used in calculations of estimated intake from food. In addition, also the fat content of the samples and, in the case were several congeners are summed up, the number of congeners with levels beneath the LOQ are presented. The estimated market basket-intakes of the studied POPs, based on presented mean occurrence values from four cities, are given in Table 3 and Fig. 2. In the table, the mean intake from the various food groups is given, together with the total intake. The estimated intake of the two major POPs, PCBs and the DDTs, is each about 500–600 ng/day. The PCBs and DDTs are dominating, on weight basis, whereas the dioxins/dioxin-like PCBs, not shown in Fig. 2, contribute very little to the total weight-based POP intake (and even less, 0.01%, on ‘‘TEQ-adjusted’’ weight basis). However, the high toxicity and low TDI value make the dioxins nevertheless a great health concern. The contribution of six different Pfood groups P to the total intake of dioxins (total-TEQ), PCBs, PBDEs, and P DDTs is shown in Fig. 3. From this figure it is clearly shown that fish is a major contributor (33–57%) to the total POP intake for Swedish consumers, but that also meat, diary products and fats/oils are important factors for POP intake.

The presented intake estimations are based on occurrence values where levels below the quantification limit are treated as they are half of this limit i.e.
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rected weight (in pg/day), based on earlier measurements, to be at least three to four times higher. If we look at the food-specific sources of POP intake we clearly see that fish often gives a large contribution to the total POP intake. Moreover, the POP levels in fish in comparison to other food groups are even more pronounced than the POP

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intake from fish compared to intake from other sources. This comes from the fact that we, on weight basis, eat less fish than we do of many other food groups. The basis for the present estimation is the occurrence data of POPs and the data on the Swedish per capita consumption of different food items. Both these data sets

Table 2 Levels of analysed POPs in food homogenates of selected Swedish market basket sample groups, based on samples collected in four Swedish cities Dioxins (pg WHO–TEQ/g fresh wt.) PCDD/DFs

PCBs

Total-TEQ

PCBs (ng/g fresh wt.) P PCBs PCB 153

(a) Levels of dioxin + dioxin-like PCB TEQsa, PCBsb and PBDEsc in analysed food homogenates Fish Malmoe 0.304 0.568 0.872 7.62 Gothenb. 0.188 0.586 0.774 14.2 Uppsala 0.328 0.465 0.793 8.30 Sundsvall 0.580 0.380 0.96 8.18 Mean 0.350 0.500 0.850 9.58 % fat 6.1 7.3 7.3
PBDEs (ng/g fresh wt.) P PBDEs BDE 47

1.74 3.24 1.91 1.84 2.18

0.615 0.775 0.509 0.639 0.634 7.2 0/5

0.442 0.651 0.373 0.445 0.478

Meat Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.061 0.061 0.056 0.067 0.061 13.0 15/17

0.027 0.044 0.026 0.025 0.030 12.3 7/9

0.088 0.105 0.082 0.092 0.092

0.530 0.493 0.446 0.453 0.481 12.3 17/23

0.161 0.155 0.129 0.128 0.143

0.060 0.043 0.048 0.032 0.046 12.9 3/5

0.029 0.016 0.017 0.012 0.018

Dairy Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.026 0.035 0.020 0.030 0.028 4.8 15/17

0.012 0.007 0.009 0.023 0.013 5.0 6/9

0.038 0.042 0.029 0.053 0.041

0.225 0.223 0.122 0.154 0.181 5.0 13/23

0.070 0.057 0.029 0.044 0.050

0.026 0.019 0.014 0.014 0.018 5.2 3/5

0.014 0.008 0.004 0.006 0.008

Egg Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.070 0.034 0.116 0.115 0.084 10.6 14/17

0.145 0.035 0.179 0.231 0.148 11.1 2/9

0.215 0.069 0.295 0.346 0.232

1.26 0.423 1.68 1.96 1.33 11.1 5/23

0.320 0.090 0.500 0.645 0.389

0.047 0.025 0.044 0.054 0.042 10.2 3/5

0.017 0.005 0.015 0.020 0.014

Fats Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.278 0.281 0.287 0.282 0.282 69.8 16/17

0.141 0.141 0.141 0.141 0.141 69.1 8/9

0.419 0.422 0.428 0.423 0.423

1.30 1.20 1.20 1.20 1.22 69.1 22/23

0.164 0.06 0.06 0.06 0.086

0.184 0.150 0.150 0.150 0.159 68.7 3/5

0.03 0.03 0.03 0.03 0.03

Pastry Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.107 0.093 0.103 0.084 0.097 24.0 16/17

0.049 0.047 0.048 0.046 0.048 21.9 8/9

0.156 0.14 0.151 0.13 0.145

0.401 0.401 0.401 0.401 0.401 21.9 22/23

0.02 0.02 0.02 0.02 0.02

0.068 0.095 0.102 0.121 0.097 22.2 3/5

0.01 0.023 0.024 0.033 0.022

(continued on next page)

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Table 2 (continued) P

HCB DDTs p,p 0 -DDE P P (b) Levels of DDTse, HCB, HCHsf, and -chlordanesg in analysed food homogenates (in ng/g fresh wt.) Fish Malmoe 5.99 4.08 0.792 Gothenb. 9.80 5.675 1.29 Uppsala 5.96 4.02 0.881 Sundsvall 6.34 4.28 0.964 Mean 7.02 4.51 0.981 % fat 7.3 7.3
HCHs

Chlordanes

0.652 1.60 0.779 0.805 0.960 7.3 0/3

1.90 3.41 2.11 2.18 2.40 7.3 0/4

Meat Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.506 0.742 0.461 0.421 0.533 12.3 3/4

0.306 0.542 0.261 0.221 0.332

0.125 0.126 0.127 0.117 0.124 12.3

0.054 0.061 0.072 0.057 0.061 12.3 1/3

0.04 0.04 0.04 0.04 0.04 12.3 4/4

Dairy Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.314 0.12 0.113 0.101 0.162 5.0 3/4

0.265 0.090 0.083 0.071 0.127

0.108 0.126 0.066 0.082 0.096 5.0

0.056 0.053 0.035 0.04 0.046 5.0 0/3

0.010 0.010 0.008 0.010 0.010 5.0 3/4

Egg Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.875 0.5 0.974 0.58 0.732 11.1 2/4

0.7 0.332 0.679 0.498 0.552

0.165 0.126 0.163 0.157 0.153 11.1

0.086 0.064 0.05 0.053 0.063 11.1 1/3

0.094 0.024 0.094 0.078 0.073 11.1 2/4

Fats Malmoe Gothenb. Uppsala Sundsvall Mean % fat
1.5 1.5 1.5 1.5 1.5 69.1 4/4

0.3 0.3 0.3 0.3 0.3

0.223 0.205 0.204 0.212 0.211 69.1

0.18 0.18 0.18 0.18 0.18 69.1 3/3

0.24 0.24 0.24 0.24 0.24 69.1 4/4

Pastry Malmoe Gothenb. Uppsala Sundsvall Mean % fat
0.5 0.5 0.5 0.5 0.5 21.9 4/4

0.1 0.1 0.1 0.1 0.1

0.02 0.02 0.02 0.02 0.02 21.9

0.158 0.117 0.156 0.114 0.136 21.9 2/3

0.08 0.08 0.08 0.08 0.08 21.9 4/4

a b c d e f g

PCDD/DF–TEQ (17 congeners), PCB–TEQ (nine congeners). Sum of 23 PCB congeners. Sum of 5 PBDE congeners. No. of values
contain elements of uncertainty. In case of the consumption data, they are based on production and trade statistics, which represents a consumption level which is probably higher than what people actually eat. In addition, these

data give only a mean value and do not give information on individual consumption patterns. In case of the analytical methods, the many analyses showing levels less that the LOQ will increase the uncertainty, and this was most

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Table 3 Calculated intakes of persistent organic pollutants (POP) intakes from six individual food groups and summarised (nd = 1/2LOD; no. of congeners analysed given in brackets) POP intake (TEQ-based intakes in pg/day*, all other POPs in ng/day)

Compound

Fish DD/DF–TEQ* PCB–TEQ* Total-TEQ* P PCB(23) PCB 153 P PBDE(5) BDE 47 P DDTs(4) p,p 0 -DDE

Meat

Diary pr.

12.8 18.2 31.0

9.52 4.75 14.3

12.8 5.91 18.7

2.11 3.73 5.85

349 79.4

74.8 22.2

83.6 23.1

33.5 9.80

23.1 17.4

7.13 2.80

256 164

HCB P PHCHs(3) chlordanes(4)

35.7 35.0 87.4

8.40 3.69

82.8 51.7

75.2 58.6

19.3 9.49 6.22

44.3 21.2 4.62

Daily POP intake (ng/day) 700 600 500 400 300 200 100 0

615

B PC m Su

523

114

50.9 DE PB m Su

T DD m Su

B HC

81

115

Hs HC m su

s ne da r o hl -c m u s

Fig. 2. Estimated daily intakes of the studied POPs, except for the dioxins/dioxin-like PCBs, in the market basket survey.

pronounced for the dioxins/dibenzofurans (DD/DF–TEQ) P and less critical for the PCBs. As could be seen in Table 2 especially fats/oils and pastry analyses resulted in levels almost exclusively beneath the LOQ, which will introduce a considerable amount of uncertainty in the intake calculations of these food groups. If these and other potential types of uncertainties (including uncertainties in consumption statistics and sample representativity) are added together, it is obvious that the intake values calculated from market basket studies are only approximate and should be used with caution. The present study could be compared to earlier intake estimations, including the previous Swedish market-basket study performed in 1994 (Mo¨re et al., 1995). This older market basket study show POP intakes that are considerably (three to four times) above those reported in the present study (Table 5). Comparisons could also be made with Swedish intake studies based on POP levels in individual food items in combination with statistical or questionnaire data on consumption of individual foods. Such studies were published in 1996 (Wicklund Glynn et al., 1996; using

Egg

1.07 0.353 18.4 13.9 3.86 1.59 1.84

Fats, oils

Pastry

Total

13.5 7.05 20.6

3.63 1.79 5.40

54.4 41.4 95.8

58.9 4.12

15.0 0.750

7.58 1.44

3.62 0.826

71.9 14.4 10.1 8.63 11.5

18.8 3.75 0.751 5.10 3.00

615 139 50.9 26.5 523 306 114 81.0 115

occurrence data from the early 1990s) and 2002 (Lind et al., 2002; occurrence data mainly from 1998 to 1999, presented as mean values). In the study from 1996, the estimated intake of dioxins and PCBs were considerably higher than those presented here, but the more recent study from 2002 gave results for a number of POPs more in accordance with the present estimation (Table 5). As earlier stated, the difference in intake levels between the different Swedish intake studies is likely a result both of a reduction of POP levels in many food items, as well as the fact that different methods and approaches were used in these cases. For example, in the earlier market basket study by Mo¨re and co-workers from 1994, the use of total homogenates (solid and liquid) instead of homogenates of several food groups as in the present study may influence the final intake estimates. The presently reported POP intake in Sweden could also be compared to respective data from other countries. In the Nordic countries intake estimations on dioxins have recently been performed. In Norway, the Norkost survey from 1997 resulted in a dioxin (total-TEQ) intake of 139 pg I-TEQ/day (SCOOP, 2000), while a Finnish total diet study came up with 100 pg WHO–TEQ/day (Kiviranta et al., 2001). In addition, in a recent Finnish market basket study the dioxin (PCDD/PCDFs P and PCBs) intake was 114 pg WHO–TEQ/day, the PCB intake was 1200 ng/ day, and the PBDE intake 44 ng/day. The comparably high estimated PCB intake could be noted, whereas the dioxin and PBDE intakes are similar to the Swedish ones. In examples of dioxin and dioxin-like PCB intake estimations for adult populations from other countries (in pg WHO– TEQ/kg bw/day), 1.2 pg was estimated in Holland (Baars et al., 2004), 1.36 pg in Spain (Llobet et al., 2003b), 2.2– 2.4 pg in USA (Schecter et al., 2001) and 3.2 in Japan (Tsutsumi et al., 2001; ND = 1/2 LOD). These presented intake data for dioxins and dioxin-like PCBs are similar, and in some cases clearly higher, to the value estimated for Swedish consumers in the present study, i.e. 1.3 pg TEQ/kgbw/day (if
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P.O. Darnerud et al. / Food and Chemical Toxicology 44 (2006) 1597–1606 POP levels in dairy prod (ng/g fr.w.) 0.35 0.3

totalTEQ (pg/g!) sumPCBs

0.25

sumPBDEs

0.2

sumDDTs

0.15

HCB HCHs

0.1

chlordanes

0.05 0 Malmoe

Gothenb.

Uppsala

Sundsvall

Fig. 4. Levels of selected POPs in dairy products from food baskets from four Swedish sampling locations, possibly indicating a spatial differences with decreasing levels from south to north.

Table 4 Estimated daily POP intakes, per individual and per kg body weight basis (in brackets), based on either lower-bound, medium-bound or upperbound food levels (TEQ-based intake in pg/kgbw/day*, all other POPs in ng/kgbw/day; mean weight 73.7 kg, from Riksmaten 1997–1998) Compound

PCB–TEQ* DD/DF–TEQ* Total-TEQ* P PPCB PPBDE DDT

Fig. 3. Relative contribution from the different P food groups to the P estimated total intakes of dioxins/dioxin-like PCBs, PCBs, DDTs and P PBDEs in the market basket survey.

If we look at the POP levels in food baskets from the four different cities, there are differences that in several cases may reflect geographical trends, production forms, or have other sample-related explanations. The levels P someP of PCBs, DDTs and PBDEs in meat products from the Sundsvall market basket were 85%, 83% and 53%, respectively, of that found in the Malmoe basket, and the corresponding values for dairy products were 68%, 32% and 53%, respectively (see Fig. 4). These differences were apparently not seen for the dioxins. The data are in agreement with those showing a geographical trend in fat from Swedish-produced bovines and pig, with higher levels in

Estimated daily intake (per individual or (per kgbw)) Lower-bound

Medium-bound

Upper-bound

27.5 (0.37) 18.8 (0.26) 44.5 (0.60) 508 (6.89) 37.0 (0.50) 387 (5.25)

41.4 (0.56) 54.4 (0.74) 95.8 (1.30) 615 (8.34) 50.9 (0.69) 523 (7.10)

58.6 (0.79) 82.8 (1.12) 141 (1.92) 694 (9.42) 64.9 (0.88) 658 (8.93)

samples from southern Sweden (Wicklund Glynn et al., 2000). The authors speculate that a possible reason for this south–north gradient may be a higher degree of environmental contamination in the more densely populated southern part of the country. In case of eggs, lower POP levels were generally observed in the Gothenburg eggs, although samples are few. A possible explanation to these discrepancies could be that the sampled eggs come from different production forms, as we know that eggs from hens that are allowed to breed outdoors, e.g. in ecological production forms, may have higher levels of e.g. dioxins than eggs produced in conventional farms (Schuler et al., 1997). However, in this study we have not been able to track the eggs as regards to the production form. Likewise, a tendency of higher POP levels in fish products from Gothenburg could be observed but not explained. In case of the Swedish values, the estimated total intakes P are below (total-TEQ: 1.3 pg/kgbw/day) or well below ( DDT: 8.9 ng/kgbw/day) internationally acceptable intake limits (total-TEQ 2 pg/kgbw/day – SCF, P 2001; DDT 10 000 ng/kgbw/day – WHO, 2001), if non-quantified values are set to 1/2 LOD. However, the distribution in intake levels of POPs has been found to

P.O. Darnerud et al. / Food and Chemical Toxicology 44 (2006) 1597–1606

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Table 5 The result of the present POP intake estimation in comparison with other Swedish intake studies Sample collected year Dioxins (total-TEQ)d P PPCB DDT P PBDE HCB P HCH P chlordanes

Unpublished results 1995a 1994 2430 2030

Wicklund Glynn et al. (1996)b ca. 1990

Lind et al. (2002)c 1998–1999

Present study (nd = 1/2 LOD) 1999

255–300 3200

89–106 760–867 543–605 41–47

96 615 523 51 114 81 115

330 320

Estimated intakes in ng/kgbw/day. a Market basket study; survey data and cesium-137 results in Mo¨re et al. (1995). b Based on POP levels in individual food items and per capita consumption data. c Based on POP levels in individual food items and food frequency questionnaire. d Dioxin intake in pg WHO–TEQ/kgbw/day.

be wide. In case of the dioxins more than 10% of the Swedish population is estimated to have an intake over the TDI of 2 pg total WHO–TEQ/kgbw (Lind et al., 2002). Therefore, the lack of individual intake data in the present study conceals variations in consumption habits, which must be kept in mind when discussing the resulting intake values. To conclude, the present Swedish market basket study presents average intake data of POPs, based on analyses of six food groups mainly representing food of animal origin. Fish is the single P food group Pcontributing most to the total POP intake. PCBs and DDTs are the two compound groups showing the largest intake by weight, but the dioxin intake, although much lower on weight basis, is of equal or perhaps even greater relevance in a risk assessment perspective. The resulting intake levels estimated in this study are similar to data from a recent Swedish intake study (Lind et al., 2002), in which individual food consumption data were used. This gives support for the market basket method as an efficient monitoring instrument that can be suitable e.g. in time trend studies. Acknowledgements The authors thank Ingalill Gadhasson and Elvy Netzel for invaluable help with sample collection, preparation and organisation during the study. The skilful analytical support from Lena Hansson and Lotta Larsson is acknowledged. The Environmental Monitoring Section at the Environment Protection Agency in Sweden financially supported this study. The authors thank Ms Merethe Andersen for technical assistance. References Atuma, S.S., Aune, M., 1999. Method for the determination of PCB congeners and chlorinated pesticides in human blood serum. Bull. Environ. Contamin. Toxicol. 62, 8–15. ¨ ., Larsson, Atuma, S.S., Linder, C.-E., Wicklund Glynn, A., Andersson, O L., 1996. Survey of consumption fish from Swedish waters for

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