Exposure assessment to bisphenol A (BPA) in Portuguese children by human biomonitoring Luísa Correia-Sá 1,2 & Monika Kasper-Sonnenberg 3 & André Schütze 3 & Claudia Pälmke 3 & Sónia Norberto 2 & Conceição Calhau 2 & Valentina F. Domingues 1 & HolgerM. Koch 3 Abstract Exposure to bisphenol A (BPA) is known to be widespread and available data suggests that BPA can act as an endocrine disruptor. Diet is generally regarded as the dom- inant BPA exposure source, namely through leaching to food from packaging materials. The aim of this study was to eval- uate the exposure of 110 Portuguese children (4–18 years old), divided in two groups: the regular diet group (n = 43) com- prised healthy normal weight/underweight children with no dietary control; the healthy diet group (n = 67) comprised children diagnosed for obesity/overweight (without other known associated diseases) that were set on a healthy diet for weight control. First morning urine samples were collected and total urinary BPA was analyzed after enzymatic hydrolysis via on-line HPLC-MS/MS with isotope dilution quantifica- tion. Virtually, all the children were exposed to BPA, with 91% of the samples above the LOQ (limit of quantification) of 0.1 μg/L. The median (95th percentile) urinary BPA levels for non- normalized and creatinine-corrected values were 1.89 μg/L (16.0) and 1.92 μg/g creatinine (14.4), respectively. BPA levels in the regular diet group were higher than in the healthy diet group, 1 REQUIMTE/LAQV - Instituto Superior de Engenharia do Porto do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal 2 CINTESIS - Centro de Investigação em Tecnologias e Sistemas de Informação em Saúde, Centro de Investigação Médica, Faculdade de Medicina da Universidade do Porto, 2° piso, edif. Nascente, Rua Dr. Plácido da Costa s/n, 4200-450 Porto, Portugal 3 Institute for Prevention and Occupational Medicine of the German Social Accident Insurance - Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany but differences were not significant. Calculated daily BPA intakes, however, were significantly higher in children of the regular diet group than in children of healthy diet group. Median (95th percentile) daily intakes amounted to 41.6 (467) ng/kg body weight/day in the regular diet group, and 23.2 (197) ng/kg body weight/day in the healthy diet group. Multiple logistic regression analysis re- vealed that children in the healthy diet group had 33% lower intakes than children in the regular diet group (OR 0.67; 95% CI 0.51–0.89). For both groups, however, urinary BPA levels and daily BPA intakes were within the range reported for other children’s populations and were well below health guidance values such as the European Food Safety Authority (EFSA) temporary tolerable daily intake (t- TDI) of 4 μg/kg body weight/day. In addition, lower daily BPA intakes were more likely linked with the inherent dietary approach rather than with high BMI or obesity. Keywords Bisphenol A . Exposure assessment . Human biomonitoring . Urine . Children . Diet Introduction Bisphenol A (BPA) was first synthesized in the early twentieth century. However, its beneficial chemical and physical prop- erties as a plasticizer were only discovered later, with the production of epoxy resins and polycarbonate plastics (Geens et al. 2012a). Its industrial production volume is ap- proximately 2.9 million tons per year, making BPA one of the chemicals with the highest production volume worldwide (Aaroe Morck 2012). BPA is used in the production of several consumer products including food/beverage can linings, stor- age containers and packing material (such as paperboard), plastic bags, dental sealants, thermal paper, medical