Environ. Sci. Technol. 2010, 44, 6297–6304
Estimation of Daily Intake of Organohalogenated Contaminants from Food Consumption and Indoor Dust Ingestion in Romania A L I N C D I R T U * ,†,‡ A N D A D R I A N C O V A C I †,§ Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium, Department of Chemistry, “Al. I. Cuza” University of Iasi, Carol I Bvd. No 11, 700506 Iasi, Romania, and Laboratory of Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
Received April 18, 2010. Revised manuscript received July 12, 2010. Accepted July 15, 2010.
We estimated human exposure to organohalogenated contaminants (OHCs), including organochlorine pesticides (OCPs), such as hexachlorocyclohexanes (HCHs), DDT and metabolites, hexachlorobenzene, and chlordanes, but also polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD), through food consumption (mainly food of animal origin) and indoor dust ingestion in Romania. A total of 71 food samples (meat, diary products, vegetable cooking oil, and eggs from urban supermarkets and rural areas) and 18 indoor dust samples were collected from Iasi, Eastern Romania. HCHs and DDTs were the most prevalent OCPs in both food and dust samples. Higher levels of OCPs were measured in food samples collected from rural areas compared to those from urban supermarkets, except milk-based products for which no significant differences could be recorded. However, levels of contamination with HCHs in milk-based products were occasionally higher than current European maximum residue levels (MRLs). AboveMRL levels of DDTs were also recorded in eggs from rural areas. In dust, DDTs (median concentration of 1050 ng/g) were the most prevalent contaminants and p,p′-DDT was consistently the main contributor of sum DDTs, with a contribution between 50 and 75%. Surprisingly, OCPs, mainly DDT, were found at elevated levels in indoor dust samples (median concentrations for sum OCPs of 1200 ng/g dust). This suggests the importance of dust as an exposure route for pesticides (especially at contaminated sites), since dust is not commonly considered in exposure assessments for these chemicals. The main contributor to the sum PBDEs in dust samples was BDE 209 (median concentration of 495 ng/g), with a contribution between 94 and 99%. We estimated that the dietary intake * Corresponding author mailing address: Department of Chemistry, “Al. I. Cuza” University of Iasi, Carol I Bvd., No 11 700506 Iasi, Romania; tel: +40 232 20 1308; fax: +40 232 20 1313; e-mail:
[email protected]. † Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp. ‡ Department of Chemistry, “Al. I. Cuza” University of Iasi. § Laboratory of Ecophysiology, Biochemistry and Toxicology, University of Antwerp. 10.1021/es101233z
2010 American Chemical Society
Published on Web 07/26/2010
of ΣHCHs and ΣDDTs is high for both adults (1500-2100 ng/ day) and toddlers (1100-1500 ng/day), while the PCB dietary intake was estimated at 200 ng/day for adults, being compared to other European studies. The contribution of dust ingestion to the daily intake of PBDEs is increased in comparison to intake of other chlorinated contaminants, while food consumption seems to be more important than dust for the HBCD intake. However, neither BDE 209 nor HBCD were measured at levels above method LOQ in any food samples and their dietary intake is probably overestimated because nondetects were replaced by 1/2 LOQ. The estimated intakes obtained in the present study are in good agreement with the higher concentrations of OCPs and the low levels of PBDEs reported recently in Romanian human samples.
Introduction Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were widely used worldwide until restrictions were introduced in the late 1970s (1). However, despite these measures, these compounds are still among the most prevalent environmental pollutants and are present in food for human consumption. Environmental levels of brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), have been continuously increasing in the past decade (2-4). Their applications vary from soft furnishings and carpets to casings for electronic equipment (for PBDEs) or extruded and expanded polystyrene foam used as thermal insulation in the building industry or in upholstery textiles (for HBCD) (5). PBDEs were sometimes added at considerable amounts in treated polymers (up to 30% by weight in casing for electronic equipment); whereas, due to its efficient flame retardancy, lower levels were required for HBCD (0.7 to 2.5%) (6, 7). As they are not chemically bound to the polymer (5), BFRs migrate from these products into the environment, contaminating indoor air and dust (8, 9), and foodstuffs (10, 11). Exposure through these media ultimately leads to their accumulation in humans (12, 13). The presence of BFRs in human tissues is of particular concern because of their neurodevelopmental and endocrine-disruptive toxicological potential (14). Due to their physicochemical properties, organohalogenated contaminants (OHCs) are mainly found in lipid-rich foods of animal origin, such as meat, fish, and dairy products, which constitute an important part of our daily diet. It has been suggested that food of animal origin is responsible for more than 90% of the average human intake of PCBs and OCPs (15). For PBDEs and HBCD, ingestion of indoor dust has been indicated as an important source for human intake (16-18). Because of similarities in the properties, environmental behavior, and toxicological profiles of various classes of OHCs, there is a need to evaluate human exposure considering the most important sources, such as lipid-rich food and indoor dust. Recent studies reported elevated levels of OCPs in human serum, milk, and hair samples from the Eastern part of Romania (19-22). Polybrominated diphenyl ethers (PBDEs) were, in contrast, present at very low levels in human serum (20). However, while dietary exposure, generally recognized as the most important source to OHCs (23-25), may explain the human levels of OCPs and PCBs, there is still little knowledge about the influence of combined exposure sources (diet and dust) for nonoccupationally exposed populations. Therefore, the present study aims at estimating human exposure to OHCs, such as OCPs, PCBs, PBDEs, and HBCD, VOL. 44, NO. 16, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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through consumption of food of animal origin and indoor dust ingestion in Eastern Romania. The estimation of daily intake for these chemicals was hereby assessed based on monthly food consumption recommendations by local authorities and on studies related to dust ingestion by humans. Particular attention was given to estimation of the daily intake of OHCs for toddlers.
Materials and Methods Sample Collection. Iasi is Romania’s third largest city (approximately 350,000 inhabitants) and has the second largest installed industrial capacity in Romania; agriculture represents the second main branch in the economy of Iasi county. Previous studies showed elevated levels of OHCs in human samples collected from this area (19-22, 26). Therefore, to evaluate the sources for human exposure to such chemicals, 71 food samples and 18 indoor dust samples were collected in June-September 2007 from Iasi, Eastern part of Romania. Selected food samples were included, such as several meat products (pork, beef, and chicken steak, salami and pork sausages), diary products (cheese, butter, milk, cream), vegetable cooking oil, and eggs. Among food samples included in this study, 50 were collected from 3 large-chain supermarkets from Iasi City and were considered as urban samples. The remaining 21 food samples were home-produced in local farms and collected from the rural area around Iasi. Each food sample included in this study was obtained by pooling at least three subsamples of the same category. The samples were homogenized immediately after collection and stored at -20 °C until further treatment. Dust samples were collected from homes located in Iasi city (n ) 14) and from homes located in the rural area (n ) 4) around Iasi, these locations being considered as remote areas for contamination with BFRs. Although we are aware that a number of four samples is too low to allow for statistical comparisons between rural and urban homes, this gives an indication of trends which can be expected in case of a higher sample size. It also allows a direct association with food samples collected in rural areas for a better exposure assessment. At each dust sampling location, 1 m2 of carpet was vacuumed for 2 min. Samples were collected using nylon sample socks (25-µm pore size) that were mounted in the furniture attachment tube of the vacuum cleaner. After sampling, socks were closed with a twist tie, sealed in brown closed glasses and stored at -20 °C. Before and after sampling, the furniture attachment was cleaned thoroughly using a disposable wipe impregnated with iso-propanol. Sample Preparation. The following classes of OHCs were targeted for analysis from each of the collected samples: OCPs including R-, β-, γ-, and δ-HCH (expressed as HCHs), p,p′DDE, o,p′-DDT, p,p′-DDD, and p,p′-DDT (expressed as DDTs), hexachlorobenzene (HCB), oxychlordane (OxC), trans-nonachlor (TN); PCB congeners (118, 153, 138, 187, 183, 156, 180, and 170) and PBDE congeners (28, 47, 100, 99, 154, 153, 183, and 209). Detailed information regarding the chemicals and materials employed in the study is given in the Supporting Information. The methods used for the analyses of food and indoor dust have previously been described (11, 17, 25). Depending on the type of sample, 0.2-4 g of homogenized food (depending on the lipid content) and 0.25 g of dust were dried using anhydrous Na2SO4, spiked with internal standards and Soxhlet extracted for 2 h (hotextraction mode) with n-hexane/acetone (3:1, v/v). For food analysis, an aliquot (∼1/8) of the extract was used for gravimetrical lipid determination (105 °C, 1 h). Cleanup was achieved by column chromatography on ∼8 g acid silica (45% H2SO4, w/w) and successively eluted with hexane and dichloromethane. The eluate was concentrated to near dryness and reconstituted in 100 µL of iso-octane. 6298
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For the analysis of OCPs and PCBs, a GC/MS system operated in ECNI or EI mode equipped with a 25 m × 0.22 mm × 0.25 µm HT-8 capillary column was employed, while the analysis of PBDEs and HBCD was performed on a GC/ MS system operated in ECNI mode and equipped with a 15 m × 0.25 mm × 0.10 µm DB-5. Detailed information regarding GC/MS conditions and quality assurance issues, including results from interlaboratory exercises (Tables SI1-SI-4), is given in the Supporting Information. Statistical Analysis. All statistical analyses were performed using SPSS 15.0 for Windows (LEAD Technologies, Inc., USA) and XLStat-Pro version 2007.7 (Addinsoft 2007). To obtain preliminary information regarding the exposure level of OHCs through food consumption or indoor dust ingestion for the Romanian population, levels below LOQ were replaced with 1 /2 LOQ for statistical calculations. Because most of the data were not normally distributed (Shapiro-Wilk test, p > 0.05), median levels were further used instead of mean concentrations to characterize analyte variations in each type of sample. The level of significance was set at R ) 0.05 throughout this study.
Results and Discussion This is the first study that estimates the dietary exposure to OHCs of a population from Romania through food and indoor dust ingestion. For food samples, we recorded significant differences in the concentrations of HCHs, DDTs, and PCBs in samples from supermarkets (in text - urban samples) compared to samples collected from private farms located in rural areas around Iasi City (in text - rural samples). Therefore, the differences were indicated in the text and Table 1 when each group of contaminants was addressed. Additionally, we have found a wide variation in the OHC concentrations across the sampled food groups. Concentrations and Profiles of OHCs from Food and Dust. OHC concentrations in food and indoor dust were expressed as median values (ng/g of sample, wet weight basis in case of food samples) and an overview of the concentrations depending on the analyte and food item, together with lipid content (%) for each analyzed food item, are presented in Table 1. Regarding the profile of contaminants, the main contributors to the sum of OHCs differed for each analyzed matrix. Higher levels in food were obtained for samples with higher lipid content, such as butter, cheese, or pork sausage. As expected from our previous studies on OCPs and PCBs in Romanian human serum (20, 22, 28), milk (19), and hair samples (21), HCHs and DDTs were the most prevalent OCPs found in food and dust samples. When OHC concentrations were compared with current European maximum residue levels (MRLs) (27), levels of contamination higher than recommended values were occasionally found only in milkbased products (such as butter, cheese, or milk cream), but not in eggs and meat products (Table 1). A plausible explanation for these findings is that milk-based products are usually obtained locally by collecting milk directly from rural areas and processing it afterward. Since previous studies showed that rural environment in Romania is more contaminated with these OHCs compared to urban areas (20, 26), it is possible that such food products are more contaminated with OCPs than those obtained at farms with a stricter food control system. Results presented in Table 1 include also the OHC concentrations in specific food products from rural areas. For milk-based products, the OCP concentrations did not differ significantly between rural and urban samples, but occasionally levels higher than the EU MRLs were measured for HCHs in sheep cheese or milk cream. The profiles of OHCs were similar to that measured in the same food category collected from the urban supermarkets. High median concentrations of DDTs in eggs were encountered in rural
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milk cream
cheese (cow)
cheese (sheep)
butter
pork sausage
salami
pork
chicken
beef
indoor dust
vegetable oil eggs
diary products
meat products
measured MRL measured MRL measured MRL measured MRL measured MRL measured MRL measured MRL measured MRL measured MRL measured measured MRL
2/0 6/3 7/5 7/0 4/0 3/0 6/4 8/5 2/1 2/0 3/3 18
N (U/R) 10 2 15 21 23 71 26 19 30 100 9 -
lipid (%) 2.5 300 0.5 300 0.55 300 1.2 300 2.2 300 20.5 7 10 7 5.3 7 13.5 7 0.9 0.5 30 160
U
R
11
19
4.6
8
-
-
-
1.6
4
-
ΣHCHs R
0.4
0.6
0.5
0.9
-
-
-
0.04
0.15
-
HCB
0.04 200 0.02 200 0.04 200 0.08 200 0.08 200 1.2 10 0.7 10 0.4 10 0.6 10 0.04 0.01 20 0.75
U
R
0.2
0.04
0.2
0.15
-
-
-
0.04
0.05
-
OxC
0.04 50 0.01 50 0.04 50 0.04 50 0.04 50 0.14 2 0.07 2 0.04 2 0.04 2 0.04 0.01 5 0.09
U 0.02 0.01 0.02 0.02 0.02 0.03 0.02 0.02 0.02 0.02 0.01 0.1
U
TN
0.1
0.02
0.04
0.03
-
-
-
0.02
0.05
-
R
95
30
16
13.5
-
-
-
5
65
-
R
ΣDDTs
6.4 1000 2.9 1000 2.7 1000 5.0 1000 6.7 1000 23 40 8 40 6.4 40 26 40 2.6 4.4 50 1050
U
0.3 0.4 0.4 0.3 0.3 1.9 0.8 0.9 2 0.3 0.3 26.5
U
5
2.8
1.8
0.9
-
-
-
0.5
4.3
-
R
ΣPCBs
0.15 0.02 0.12 0.13 0.12 0.11 0.11 0.14 0.11 0.1 0.03 495
U
0.05
0.2
0.1
0.1
-
-
-
0.1
0.15
-
R
ΣPBDEs
R
0.04
0.25
0.25
0.25
-
-
-
0.25
0.04
-
HBCD
0.25 0.04 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.04 190
U
TABLE 1. Median Concentrations (ng/g Wet Weight for Food and ng/g Dry Weight for Dust) for Each OHC Investigated, Maximum Residue Levels (MRLs) for Pesticides in Food Products Stated by the European Commission, 2004 (27), Number of Samples Included in Study and Lipid Content (%) for Each Food Item Analyzed (U, Samples Collected from Supermarkets; R, Samples Collected from Private Farms Located in Rural Areas), and Also for Indoor Dust Samples
samples (95 ng/g ww), exceeding the EU MRLs. For other food categories and other contaminants, higher levels were obtained in samples collected from rural compared to urban areas (Table 1), but the EU MRLs were not exceeded. Moreover, higher contamination levels with OHCs were measured in the present study compared to similar EU studies on food products (29). Since food is acknowledged as the main source for human exposure to OHCs (23), these results may explain reports that the concentration of p,p′-DDT in Romanian human serum is consistently higher than that in other Central and Eastern European countries (20), but is also more than 1 order of magnitude higher than that in Western European countries (e.g., Belgium) (22). Indoor dust was included in this study because of its recently reported importance related to human exposure to BFRs (30). Interestingly, DDTs were the most prevalent OHCs in Romanian indoor dust and p,p′-DDT was consistently the main contributor of sum DDTs, between 50 and 75% contribution. Moreover, 2 samples out of 4 collected from the rural environment around Iasi city (initially collected to represent background samples as they were collected from remote areas related to BFRs contamination) showed very high contamination level with p,p′-DDT (4600 and 15,400 ng/g dust, respectively). Previous studies that reported OCPs in house dust (31, 32), showed lower contamination (median concentrations for p,p′-DDT of 280 ng/g and maximum levels of 9600 ng/g) compared to our dust samples. Therefore, our values may be considered as the highest OCP concentrations reported in indoor dust, suggesting that, beside its importance for BFRs contamination, indoor dust represents an important source for human exposure to OCPs, especially at contaminated sites. Other OCPs measured in this study, HCB, OxC and TN, had very low concentrations in all analyzed samples (Table 1). Such results were not surprising considering previous studies aslo showed undetected to low levels of these OCPs in soil (26), human serum (20), and hair samples (21) collected from the same region. PCBs were found at considerable low levels in food when compared to HCHs or DDTs. When compared to other EU studies (24, 25, 33), food items showed similar contamination level with PCBs suggesting that human exposure in Romania to PCBs is not significantly different than that in other EU populations. This is supported by a recent study (22) which showed that serum levels of PCBs in the Romanian population are not significantly different when compared to Western Europe population. Furthermore, the PCBs profile was similar between food and indoor dust samples and consisted mainly of congeners CB 138, 153, 180, and 170, which comprise between 65 and 85% of the sum PCBs. The PCB profile obtained in dust samples included in this study was similar to that reported in previous literature (33). For BFRs, BDE 209 and HBCD could not be measured above the LOQ in any food samples. The detection frequencies for tri- to hepta-BDE congeners in food were below 30% and their profile consisted of BDE 28 > 47 > 99 > 153 (based on their median concentrations), which contributed to >85% of sum PBDEs. Contrarily to food, BDE 209 was the main contributor to the sum PBDEs in dust (median concentration of 480 ng/g, range 60-6400 ng/g), with a contribution between 94 and 99% that indicates use of the Deca-BDE commercial formulation. The profile recorded for lower PBDEs in dust was also different than for food: the main contributors were BDE 99 ≈ 47 > 153 > 183 (based on their median concentrations), which contributed to >80% to the sum tri- to hepta-BDE congeners. The importance of BDE 209 to the sum PBDEs in dust is in agreement with findings that European dust is composed mainly of BDE 209 (17) in contrast to U.S. dust which is composed equally of BDE 47, 99, and 209 6300
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(17, 34). In general, while North American dust samples are contaminated by components of Deca- and PentaBDE commercial formulations (BDE 209 and tri- to hexaBDEs, respectively) (35), dust samples from Europe are predominantly contaminated by Deca-BDE (17, 34). The PBDEs concentrations in Romanian dust samples are comparable to data from Belgium, Italy, or Canada (17, 36, 37), but are much lower than those reported from the UK (17). For food samples, the profile obtained for lower PBDEs is in agreement with previous literature, but the levels reported here are in general lower than in other studies (24, 38). However, the nondetection of BDE 209 in food is in slight disagreement with recent literature where it has been reported in some European food (36, 39, 40). Since analyses were performed by GC-MS, only total HBCD rather than specific HBCD isomers was determined. The levels of total HBCD in dust samples included in this study (median concentration of 190 ng/g, range 30-600 ng/g) were lower than those of PBDEs, but they were also 2 up to 3 times lower than in similar studies from UK, Canada, or the U.S. (18). These results suggest that HBCD had so far a limited application range in products commercialized in Romania. Regarding the profiles of contaminants measured in food and dust samples included in this study, OHCs showed differences according to the rank of abundance between the two matrices considered. For food samples, the OHCs varied in the following order: OCPs . PCBs > PBDEs ≈ HBCD. This profile differed from that in dust samples where the rank order of abundance was: OCPs . PBDEs > HBCDs > PCBs. Intake Estimation of Organochlorine Contaminants through Food and Dust. Assumptions. To estimate the intake of contaminants through food consumption, concentrations (in wet weight basis) and the official recommendation of the monthly food consumption for an adult (41, 42) were used as follows (IC, intake of contaminant, ng/day; RDC, recommended daily consumption, g/day; CC, contaminants’ concentration, ng/g wet weight): IC (ng/day) ) RDC (g/day) × CC (ng/g) To estimate toddlers’ intake, we considered 60% of the adult diet. This assumption was based on the only available documents found in the literature: (a) indications for food consumption of the adult population (42), and (b) governmental recommendations for children’s menu in day care centers (41). In this way, the contribution of food intake and dust ingestion of contaminants can be assessed for both age groups (toddlers and adults). For a preliminary evaluation of the magnitude of exposure to OHCs through dust ingestion to the population of Iasi City, we have assumed 100% absorption of intake in accordance with the literature (16, 17). We have used low adult and toddler dust ingestion values of 20 and 50 mg/day and high dust ingestion values for adults and toddlers of 50 and 200 mg/day, respectively (16, 17). These values were multiplied with the median contaminants’ levels measured in dust. Therefore, considering the above-mentioned assumptions, the estimation of daily intake (ng/day) of OHCs for adult and toddler through food consumption and indoor dust ingestion is presented in Table 2. However, it is important to mention that this study does not account for the potential decrease in OHCs content caused by food preparation techniques, and therefore the data used here to estimate the dietary exposure of Romanian population to OHCs might be slightly overestimated (38, 43). Yet, we did not include any fish samples in our food basket collected for analysis and therefore the present results might be underestimated, since fish is an important dietary source of OHCs. However, fish represents only a small part of the typical Romanian diet
TABLE 2. Estimation of Daily Intake (ng/day) of OHCs for Adult and Toddler through Food Consumption and Dust Ingestion in Romania (Results Presented for Intake Calculation through Dust Ingestion Were Divided into Two Categories: Low Intake, for Ingestion Values of 20 and 50 mg Dust/Day for Adults and Toddlers, Respectively; and High Intake, for Ingestion Values of 50 and 200 mg Dust/Day for Adults and Toddlers, Respectively). Median Values of Contaminant Concentrations Were Used for Calculations RDCa (g) ΣHCHs adult
meat products butter cheese vegetable oil eggs daily total - food based on median concentrations 5th percentile 95th percentile indoor dust-low based on median intakeb concentrations 5th percentile 95th percentile indoor dust-high based on median intakeb concentrations 5th percentile 95th percentile toddler (6-24 meat products months) butter cheese vegetable oil eggs daily total - food based on median concentrations 5th percentile 95th percentile indoor dust-low based on median intakeb concentrations 5th percentile 95th percentile indoor dust-high based on median intakeb concentrations 5th percentile 95th percentile
190 16.7 110 20 25
HCB
OxC
TN
ΣDDTs ΣPCBs ΣPBDEs HBCD
232 342 920 18 0.2 1512
8.4 6.9 2.9 20 2.3 0.5 64 6.3 2 0.8 0.9 0.4 0.006 0.004 0.002 93.2 16.4 5.8
831 387 825 52 2.2 2097
63 32 104 5.8 0.15 205
22 1.8 14 2.2 0.02 40
40 4.2 28 5 0.02 77
0.02b
420 3300 3.3
58 120 0.05
13 22 0.01
5 6 0.001
1510 3200 50
105 310 1
35 60 30.3
77 77 6
0.05b
0.3 7.3 8.2
0.01 0.14 0.12
0.001 0.001 0.02 0.01 0.01 0.007
1.7 180 124
0.16 4.5 2.6
1.6 150 75.8
0.6 16.5 15
110
0.8 18 139
0.02 0.35 5
0.002 0.002 0.05 0.02 4 1.7
4.15 460 499
0.4 11.3 38
4 370 13
1.5 41 24.3
205 552 11 0.15 907
12 1.3 0.3 38 3.8 1.2 0.5 0.5 0.2 0.003 0.002 0.001 55.5 9.6 3.4
231 495 31 1.3 1257
19 63 3.5 0.09 124
1.1 8.5 1.3 0.01 24
2.5 17 3 0.01 47
0.05b
250 1980 8.2
35 72 0.12
8 13.2 0.01
3 3.6 0.007
910 1920 124
64 190 2.6
21 36 75.8
47 47 15
0.2b
0.8 18 33
0.02 0.35 0.5
0.002 0.002 0.05 0.02 0.05 0.03
4.15 460 494
0.4 11.3 10
4 370 304
1.5 41 61
3 72
0.09 1.4
0.01 0.2
17 1830
1.6 45
16 1480
6 165
10 68 12 15
a RDC ) Recommended daily consumption (g) (41, 42). (16).
b
compared with other types of food of animal origin (41). While this study addresses the ingestion of OHCs absorbed on settled dust particles, inhalation of OHCs from suspended fine particles of present in the gas phase is a possible viable exposure route. However, air samples could not be collected due to logistical reasons and therefore inhalation of OHCs was not investigated here. Results. The dominating OCPs for daily intake through food consumption were ΣHCHs and ΣDDTs with high values for both adults (1500 and 2100 ng/day) and toddlers (1100 and 1500 ng/day). As already documented in the Romanian population (20, 21), the intake of HCB, OxC, and TN through food consumption was much lower than of other contaminants (Table 2). The human exposure to these OCPs through indoor dust ingestion was also very low. The dietary intakes of total PCBs were 200 and 125 ng/day for adults and toddlers, respectively (Table 2). These values are lower than those from Sweden (615 ng/day) (24), Finland (1200 ng/day) (44), Slovak Republic (420-1120 ng/day; results recalculated for an adult of 70 kg body weight) (45), and Belgium (400-535 ng/day) (25). Although human serum from Romania and Belgium (22) showed that there were no significant differences between countries, the dietary exposure to PCBs seems to be slightly lower. However, the total intake of PCBs via dust ingestion in Romania (low and high dust ingestion 1 and 2.6 ng/day for adults, respectively) was slightly higher
0.01 0.06
Low and high dust ingestion figures (g) for adult and toddler
than in Belgium (0.3 to 0.8 ng/day for the same exposure scenarios) (33). As shown in the literature (23), the intake of OCPs and PCBs occurs mainly dietary (>90%). Therefore, when plotting the relative contribution of the intake sources (food consumption and indoor dust ingestion; considering low and high dust ingestion scenarios) for each class of contaminant included in this study (Figure 1), the daily intake of total HCHs, DDTs, and PCBs is mainly due to food consumption for adults (>94%) and toddlers (>70%). For the high dust ingestion scenario for toddlers, the daily intake of ΣDDTs through dust is approximately 30% of the total intake (Figure 2), suggesting that dust may also be relevant in context of human exposure to other chemicals and not only for PBDEs, as already shown. As already suggested (34, 38), dietary exposure alone can not account for the PBDEs body burden typically measured in humans. In addition to food, the indoor environment, such as dust and air, may play an important role for the human exposure to PBDEs. Therefore, besides food consumption, we considered also indoor dust ingestion as an exposure source. In all scenarios considered in this study, the contribution of dust to the daily intake of BFRs is increased in comparison to intake of other chlorinated contaminants (Figures 1 and 2). For adults, the intake of sum PBDEs is similar for both sources, whereas for toddlers, intake through VOL. 44, NO. 16, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 1. Relative contribution of food and dust to daily intake of OHCs for adults in Romania when two scenarios of human exposure to indoor dust were considered: low dust ingestion of 20 mg/day and high dust ingestion of 50 mg/day (16, 17).
FIGURE 2. Relative contribution of food and dust to daily intake of OHCs for toddlers (6-24 months) in Romania when two scenarios of human exposure to indoor dust were considered: low dust ingestion of 50 mg/day and high dust ingestion of 200 mg/day (16, 17).
TABLE 3. Relative Contribution (%) of Food and Indoor Dust (Low and High Dust Ingestion Scenarios)a to the Daily Intake of Σtri- to hepta-BDEs and BDE 209 for Adults and Toddlers in Romania dust ingestion scenario adult
low (0.02 g/day)b b
high (0.05 g/day) toddler (6-24 months)
low (0.02 g/day)b high (0.05 g/day)b
food consumption indoor dust ingestion food consumption indoor dust ingestion food consumption indoor dust ingestion food consumption indoor dust ingestion
Σtri- to hepta BDEs
BDE 209a
99 1 98 2 97 3 88 12
72 28 51 49 38 62 13 87
a Concentrations for BDE 209 in food were considered as 1/2 method LOQ, since it could not be measured above method LOQ in any food samples. b Low and high dust ingestion figures (g/day) for adult and toddler (16).
dust ingestion dominates, especially for the high dust ingestion scenario for which the percentage contribution of dust to total PBDEs intake is >90% (Figure 2). In general, food consumption seems to be more important than dust for the HBCD intake, but it should be acknowledged that HBCD values in food were obtained by considering 1/2 LOQ, while HBCD was detected in all dust samples. The findings of the present study showed also that the contributions of food and dust to the intake of PBDEs were considerably different when tri- to hepta-BDEs and BDE 209 were considered separately. Therefore, for lower PBDE congeners, food consumption is more important in adults 6302
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and toddlers (>90% to the intake), while indoor dust ingestion is more important for BDE 209 (>85% for toddlers and high dust intake scenario) (Table 3). Indeed, such findings were in agreement with the dominance of BDE 209 in all dust samples. However, as mentioned above, BDE 209 could not be measured above the LOQ in any food samples, and results presented in Table 3 were obtained by replacing concentrations with 1/2 LOQ (medium-bound approach). Considering these, when assessing human exposure to PBDEs through different sources, BDE 209 should be treated separately from its lower brominated congeners, as it was also recently suggested (36).
The intake of (sum) PBDEs through dust ingestion estimated in the present study is comparable with similar studies on domestic dust samples from Belgium or Canada, but it is much lower than that reported from the U.K. or U.S. (17, 36). The results obtained in this study explain the relatively high OCP concentrations and low levels of PBDEs recently reported in Romanian human samples (20, 21, 28). Since human exposure of Romanian population to these OHCs was not shown to decrease, and in the light of reported increasing levels of BFRs in human samples, an extensive program for monitoring the contamination with OCPs, PCBs, and BFRs in different Romanian environmental compartments becomes imperiously necessary.
Acknowledgments Dr. Alin C. Dirtu acknowledges financial support from the University of Antwerp, Belgium. Dr. Adrian Covaci was financially supported by the Research Council of the University of Antwerp and by a postdoctoral fellowship from the Research Scientific Foundation - Flanders (FWO).
Supporting Information Available Specific details of analytical protocols and quality control (including results from interlaboratory tests). This information is available free of charge via the Internet at http:// pubs.acs.org.
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