Article pubs.acs.org/est
Occurrence of and Dietary Exposure to Parabens in Foodstuffs from the United States Chunyang Liao, Fang Liu, and Kurunthachalam Kannan* Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, New York 12201-0509, United States S Supporting Information *
ABSTRACT: Parabens are esters of p-hydroxybenzoic acid and are widely used as preservatives in cosmetics, pharmaceuticals, foodstuffs, including beverages. Information on the occurrence of parabens in foodstuffs and dietary exposure of humans to these chemicals is not available. In this study, food samples (n = 267) collected from Albany, New York, United States, were grouped into eight categories, namely, beverages, dairy products, fats and oils, fish and shellfish, grains, meat, fruits, and vegetables, and analyzed for five parabens by highperformance liquid chromatography-tandem mass spectrometry. The majority (>90%) of food samples contained measurable concentrations of parabens, and the total concentrations (Σparabens; sum of five parabens) ranged from below the limit of quantitation to 409 ng/ g fresh weight (mean: 9.67 ng/g; median: 0.92 ng/g). Methyl-, ethyl-, and propyl-parabens were the predominant compounds, accounting for ∼90% of the total concentrations. Butyl- and benzyl-parabens were less frequently detected. There were no significant differences in paraben concentrations among the eight food categories, including the canned foods. On the basis of the concentrations measured and per capita daily ingestion rates of foods, we estimated the daily intake (EDI; ng/kg of body weight (bw)/day)) of parabens through food ingestion. The EDI values of total parabens (calculated from the mean concentrations measured and the mean daily ingestion rates of food items) were 940, 879, 470, 273, and 307 ng/kg bw/day for infants, toddlers, children, teenagers, and adults, respectively. To our knowledge, this is the first study to report the occurrence of parabens in foodstuffs.
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INTRODUCTION The alkyl esters of p-hydroxybenzoic acid (parabens) are a group of a homologous series of chemicals that include methyl(MeP), ethyl- (EtP), propyl- (PrP), butyl- (BuP), and benzylparabens (BzP). Parabens are used as preservatives in cosmetics, pharmaceuticals, foodstuffs, including beverages.1−6 Parabens exhibit several characteristics, such as stability, water solubility, and broad-spectrum antimicrobial activity, which make them a popular preservative in consumer products.1 Humans are exposed to parabens via ingestion, inhalation, and/or dermal absorption through a wide variety of sources.1,3,7 Occurrence of parabens in urine, serum, breast milk, and breast tumors has been documented.8−15 Studies conducted by the Centers for Disease Control and Prevention (CDC) in the United States showed the presence of MeP and PrP in greater than 90% of urine samples from the U.S. general population, with concentrations on the order of several tens of nanograms per milliliter. Other paraben analogues, including EtP, BuP, and BzP, were detected but less frequently ( 0.05, one-way ANOVA). The mean and median concentrations of PrP in food samples collected in 2008, 2011, and 2012 were 1.73 and 0.027 ng/g, 1.44 and 0.023 ng/g, and 0.074 and 0.014 ng/g, respectively (p > 0.05; Table 1). The detection frequency of PrP was lower 3920
dx.doi.org/10.1021/es400724s | Environ. Sci. Technol. 2013, 47, 3918−3925
Environmental Science & Technology
Article
samples is in accordance with that reported for human urine, blood, and breast milk, in which the concentrations of MeP were higher than those of PrP and EtP.9−11,13−15,33 Parabens in Various Food Categories. In this study, food samples were grouped into eight categories as beverages, dairy products, fats and oils, fish and shellfish, grains, meat, fruits, and vegetables (Table S1, Supporting Information). The categorization of foodstuffs analyzed in this study was difficult, especially for mixed and prepared foods. The concentrations of individual and total parabens were compared among the eight categories of foods. The highest mean concentration of total parabens was found in grains (mean: 18.6 ng/g), followed by beverages (14.2 ng/g), and dairy products (9.6 ng/g). The lowest concentrations were found in fat and oils (0.27 ng/g) and fruits (0.83 ng/g). All meat and vegetable samples contained MeP, and the concentrations were in the range 0.097−43.6 ng/g (mean: 4.27 ng/g; median: 1.10 ng/g) and 0.041−69.9 ng/g (4.46; 1.06 ng/ g), respectively (Table 2). MeP also was frequently detected in grains (detection frequency: 98%), fish and shellfish (91%), dairy products (87%), and fruits (85%) (Table 2). Although the mean concentrations of MeP varied among the different categories of foods (from 0.199 ng/g in fats and oils to 14.1 ng/ g in grains), the difference was not statistically significant (p > 0.05). Overal, MeP accounted for 42−78% of the total paraben concentrations (Figure 1). EtP and PrP were the next two major parabens in food samples, accounting for 3.7−27% and 5.2−22%, respectively, of the total paraben concentrations. The concentrations and detection rates of both EtP and PrP were significantly lower than those of MeP (for the entire sample set; p < 0.05) (Table 2). The mean concentrations of EtP and PrP varied by over 2 orders of magnitude (Table 2), and the differences were not statistically significant (p > 0.05) (Figure 2). Similarly, no significant difference was found for the total concentrations (∑parabens) of parabens among food items (p > 0.05, one-way ANOVA; Figure 2 and Table 2). The major source of parabens in foods is not well known. The use of parabens as broad-spectrum antimicrobial preservatives in certain foods or ingredients used in prepared foods is a potential source. In addition, food-packaging materials can be a source of parabens in foods. We compared the concentrations of parabens in food samples that were sold in various types of packaging materials, including foods packaged in cans (canned foods). The food samples analyzed in our study were packaged mainly in four categories of materials: cans, glass, paper, and plastic. We found no significant difference in concentrations and profiles of parabens in foods packaged in the four categories of materials (p > 0.05; Figure 2 and Table S5, Supporting Information). This is different from what was reported for bisphenol A (BPA), which showed elevated concentrations in canned food samples.28,29,34 Concentrations of parabens in canned foods, fats and oils, seafood, and fruits were low. Dietary Exposure Estimation. On the basis of the mean concentrations of parabens measured and the average daily ingestion rates of the corresponding food item, we estimated daily dietary intake (EDI; ng/kg bw/day), as shown in eq 1:35
than that of MeP (63% versus 91% for the entire sample set). The highest concentration of PrP was found in a turkey breast sample (processed meat; 95.4 ng/g). Samples of yogurt (51 ng/ g), roast turkey (32.4 ng/g), and apple pie (31.3 ng/g) contained notable concentrations of PrP. Pearson correlation analysis showed that the concentrations of MeP in foods were positively correlated with the concentrations of PrP (p < 0.05; Table S4, Supporting Information). This pattern is consistent with what was reported in our recent study, which showed a significant positive correlation between MeP and PrP concentrations in indoor dust.32 EtP also was frequently (62%) found in food samples at concentrations that ranged from below LOQ to 258 ng/g (Table 1). The highest concentration of EtP was found in a red wine sample (from California). The concentrations of EtP in food samples were similar to or slightly higher than those of PrP (mean: 2.26 ng/g versus 1.51 ng/g, for the entire sample set; p > 0.05). BuP and BzP were found in less than 30% of food samples. The mean concentrations of BuP and BzP were 2 orders of magnitude lower than those of MeP and PrP (p < 0.01; Table 1). The total concentration of parabens (sum of five parabens: ∑parabens) was compared among the food samples collected during the three years (Table 1 and Figure S1, Supporting Information). Food samples collected in 2012 contained the highest ∑paraben concentrations (range: below LOQ to 409 ng/g; mean: 11.0 ng/g; median: 0.839 ng/g), which were on the same order of magnitude with those collected in 2011 (below LOQ to 150; 9.07; 1.53 ng/g) and somewhat higher than those collected in 2008 (below LOQ to 15.5; 1.97; 0.484 ng/g) (Table 1), although the differences were not statistically significant (p > 0.05, one-way ANOVA). These comparisons among foods collected at different years were tempered by the small number of samples, particularly for samples collected in 2008. The median concentration of ∑parabens (0.92 ng/g for the entire sample set; Table 1) in food was 3−4 orders of magnitude lower than that (1560 ng/g) reported for indoor dust collected from Albany, New York.32 The distribution of individual parabens (expressed as a percentage of the total) was calculated for each category of foods. Among paraben analogues, MeP, PrP, and EtP were predominant, accounting for 65.4 ± 28.6% (mean ± SD), 14.0 ± 20.1%, and 12.3 ± 19.0%, respectively, of the total paraben concentrations (Figure 1). This composition pattern in food
EDI = Figure 1. Composition profiles of parabens in foodstuffs collected from Albany, New York. The numbers within parentheses on the y axis represent the number of samples analyzed.
∑ Ci × FIR i
(1)
where C is the mean paraben concentration in food sample (ng/g) and FIR is the daily food ingestion rate (g/(kg of 3921
dx.doi.org/10.1021/es400724s | Environ. Sci. Technol. 2013, 47, 3918−3925
Environmental Science & Technology
Article
Table 2. Concentrations (ng/g) of Parabens in Several Categories of Food Itemsa BzP Beverages (n = 33) mean 0.016 (CI 95%) (0.005−0.027) median 0.005 range nd−0.134 frequency (%) 21.2 Dairy Products (n = 31) mean 0.010 (CI 95%) (0.005−0.015) median 0.005 range nd−0.052 frequency (%) 12.9 Fats and Oils (n = 5) mean 0.026 (CI 95%) (−0.024−0.076) median 0.011 range nd−0.098 frequency (%) 60.0 Fish and Shellfish (n = 23) mean 0.129 (CI 95%) (−0.093−0.351) median 0.005 range nd−2.47 frequency (%) 21.7 Grains (n = 54) mean 0.046 (CI 95%) (−0.011−0.104) median 0.005 range nd−1.54 frequency (%) 24.1 Meat (n = 52) mean 0.012 (CI 95%) (0.006−0.018) median 0.005 range nd−0.132 frequency (%) 19.2 Fruits (n = 20) mean 0.056 (CI 95%) (−0.016−0.129) median 0.005 range nd−0.679 frequency (%) 25.0 Vegetables (n = 49) mean 0.062 (CI 95%) (0.001−0.123) median 0.005 range nd−1.45 frequency (%) 46.9 a
BuP
EtP
MeP
PrP
Σparabens
0.007 (0.004−0.009) 0.005 nd−0.044 12.1
8.53 (−7.35−24.4) 0.005 nd−258 39.4
4.74 (−1.36−10.8) 0.095 nd−96.8 66.7
0.882 (−0.672−2.44) 0.005 nd−25.2 21.2
14.2 (−4.32−32.7) 0.124 nd−280 72.7
0.036 (−0.012−0.084) 0.005 nd−0.710 16.1
0.160 (0.030−0.290) 0.010 nd−1.32 48.4
5.17 (0.997−9.33) 0.344 nd− 47.5 87.1
4.23 (−0.349−8.81) 0.014 nd−50.8 58.1
9.60 (0.935−18.3) 0.581 nd−98.4 90.3
0.006 (0.003−0.009) 0.005 nd−0.010 20.0
0.031 (−0.031−0.094) 0.005 nd−0.120 40.0
0.199 (−0.131−0.529) 0.005 nd−0.509 40.0
0.009 (−0.002−0.019) 0.005 nd−0.024 20.0
0.271 (−0.150−0.692) 0.031 nd−0.718 60.0
0.009 (0.003−0.016) 0.005 nd−0.068 13.0
0.111 (−0.092−0.315) 0.009 nd−2.27 56.5
1.09 (−0.024−2.21) 0.336 nd−12.2 91.3
0.093 (0.042−0.144) 0.042 nd−0.408 69.6
1.43 (−0.121−2.99) 0.399 0.043−17.5 100
0.059 (−0.006−0.123) 0.005 nd−1.72 37.0
3.17 (−2.40−8.74) 0.048 nd−150 66.7
14.1 (−1.24−29.5) 2.25 nd−409 98.1
1.16 (−0.091−2.41) 0.104 nd−31.3 81.5
18.6 (2.39−34.8) 3.73 0.087−409 100
0.010 (0.006−0.014) 0.005 nd−0.096 23.1
0.100 (0.020−0.179) 0.018 nd−1.56 73.1
4.27 (2.10−6.44) 1.10 0.097−43.6 100
3.28 (−0.623−7.18) 0.070 nd−95.4 75.0
7.67 (2.83−12.5) 1.63 0.117−95.8 100
0.007 (0.005−0.010) 0.005 nd−0.020 25.0
0.182 (−0.042−0.406) 0.012 nd−2.07 55.0
0.462 (0.193−0.732) 0.328 nd−2.33 85.0
0.122 (−0.032−0.276) 0.005 nd−1.24 45.0
0.830 (0.324−1.34) 0.453 nd− 4.37 95.0
0.054 (−0.010−0.118) 0.005 nd−1.55 28.6
2.74 (−0.280−5.75) 0.051 nd−62.4 73.5
4.46 (1.19−7.74) 1.06 0.041−69.9 100
0.116 (0.020−0.212) 0.023 nd−2.03 69.4
7.43 (1.45−13.4) 1.59 0.106−134 100
nd = not detected; CI = confidence interval; frequency = detection frequency.
the parameters used for the EDI calculation are presented in Table S6 (Supporting Information). The EDIs of individual and total parabens from different food categories are summarized in Table 3. The highest mean and 95th percentile values for daily intakes of ∑parabens were found for infants (940 and 3510 ng/kg bw/day, respectively); this was followed, in decreasing order, by toddlers (879 and 2170 ng/kg bw/day), children (470 and 1250 ng/kg bw/day), adults (307 and 856 ng/kg bw/day), and teenagers (273 and 813 ng/kg bw/day). The EDI values from dietary sources were
bw·day)). For EDI calculation, we stratified the population into five age groups: infants (
