Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China.
Environ Sci Technol. 2013 Feb 19;47(4):2069-76. doi: 10.1021/es304659r. Epub 2013 Feb 1.
Hydroxybenzoic acid esters (parabens) are used as preservatives in foods, cosmetics, and pharmaceuticals, which results in the exposure of humans to these compounds. Parabens and its metabolite, p-hydroxybenzoic acid (p-HB) are excreted from urine in free and conjugated forms. In this study, free and total forms (free plus conjugated) of parabens and their common metabolite, p-HB, were measured in urine samples collected from U.S. children (n = 40), Chinese children (n = 70), and Chinese adults (n = 26). The median concentrations of the sum of 6 parabens (Σparabens) in urine from U.S. and Chinese children were 54.6 and 10.1 ng/mL, respectively. The median concentration of urinary parabens measured for Chinese adults was 33.2 ng/mL, which was lower than that reported for U.S. adults. Elevated concentrations of parabens (1000-10,000 ng/mL) were found in urine from some Chinese adult females. Parabens were present predominantly (>90%) as conjugated species in urine. Among the six parabens analyzed, methyl paraben (MeP) and propyl paraben (PrP) were the predominant compounds, which accounted for 57-98% and 1.4-12%, respectively, of the total concentrations. A significant positive correlation was found between the concentrations of MeP and PrP. The geometric mean (GM) concentration of p-HB was 1380 and 2370 ng/mL for Chinese children and adults, respectively. The GM concentrations of p-HB in urine from U.S. children were 752 ng/mL for girls and 628 ng/mL for boys, which were 2-3 times lower than the concentrations determined for Chinese children. There was a significant difference in the ratios of concentrations of Σparabens and p-HB between demographic groups, which suggested the existence of various exposure routes to parabens. Based on the concentrations of urinary parabens and p-HB, the daily intake (DI) of MeP and PrP was estimated. The GM DI(MeP) estimated for Chinese children was 0.5-0.7 mg/day, which was similar to those determined for U.S. children. The GM DI(PrP) (0.2-0.5 mg/day) estimated for Chinese children was 20- to 50-fold higher than the value determined for U.S. children (0.01 mg/day). The highest exposure to parabens was found for Chinese adult females, with GM DI(MeP) and DI(PrP) of 5.9 and 1.2 mg/day, respectively. Elevated exposure to PrP was found in some Chinese adult females (27 mg/day) and children (11 mg/day).
羟基苯甲酸酯（对羟基苯甲酸酯）作为防腐剂被广泛应用于食品、化妆品和药品中，这导致人类接触这些化合物。对羟基苯甲酸酯及其代谢产物对羟基苯甲酸（p-HB）以游离和结合形式从尿液中排出。本研究检测了来自美国儿童（n=40）、中国儿童（n=70）和中国成年人（n=26）尿液中对羟基苯甲酸酯及其常见代谢产物 p-HB 的游离和总形式（游离加结合）。美国和中国儿童尿液中 6 种对羟基苯甲酸酯总和（Σ对羟基苯甲酸酯）的中位数浓度分别为 54.6 和 10.1ng/ml。中国成年人尿液中对羟基苯甲酸酯的中位数浓度为 33.2ng/ml，低于美国成年人的报告值。一些中国成年女性尿液中对羟基苯甲酸酯浓度（1000-10000ng/ml）升高。对羟基苯甲酸酯主要以结合物形式存在于尿液中（>90%）。在所分析的 6 种对羟基苯甲酸酯中，甲基对羟基苯甲酸酯（MeP）和丙基对羟基苯甲酸酯（PrP）是主要的化合物，分别占总浓度的 57-98%和 1.4-12%。MeP 和 PrP 浓度之间存在显著正相关。中国儿童和成年人尿液中 p-HB 的几何均数（GM）浓度分别为 1380 和 2370ng/ml。美国儿童尿液中 p-HB 的 GM 浓度分别为女孩 752ng/ml，男孩 628ng/ml，分别比中国儿童低 2-3 倍。不同人群之间 Σ对羟基苯甲酸酯和 p-HB 浓度的比值存在显著差异，这表明存在不同的对羟基苯甲酸酯暴露途径。基于尿液中对羟基苯甲酸酯和 p-HB 的浓度，估算了甲基对羟基苯甲酸酯和丙基对羟基苯甲酸酯的每日摄入量（DI）。中国儿童估算的甲基对羟基苯甲酸酯 GM DI（0.5-0.7mg/天）与美国儿童相似。中国儿童估算的丙基对羟基苯甲酸酯 GM DI（0.2-0.5mg/天）比美国儿童（0.01mg/天）高 20-50 倍。中国成年女性对对羟基苯甲酸酯的暴露最高，其甲基对羟基苯甲酸酯 GM DI（5.9mg/天）和丙基对羟基苯甲酸酯 GM DI（1.2mg/天）分别为最高。一些中国成年女性（27mg/天）和儿童（11mg/天）体内丙基对羟基苯甲酸酯的暴露量升高。
