Biomonitoring of arsenic, cadmium and lead in urine of school-aged children from the Portuguese region of Tâmega

Human biomonitoring (HBM) is defined broadly as the measurement of biomarkers in human biological fluids or tissues. HBM measures the internal dose of a chemical resulting from integrated exposures from all exposure routes. It has been used increasingly as a tool for quantifying human exposure to chemicals in order to inform public health, risk assessment, and risk management decisions. Exposure to environmental pollutants occurs through different routes, such as inhalation, ingestion, and dermal absorption. Thus, the body burden of a specific pollutant is determined by several factors, such as the pollutants concentration, their physical and chemical properties and time of exposure, as well as individual factors, such as uptake, metabolism and excretion rates. The present biomonitoring study was conducted to assess children´s exposure to arsenic (As), cadmium (Cd) and lead (Pb) through urine analysis from a representative sample (n=525). This is a cross- sectional study of a random representative sample of children (6-12 years) from one NUTS III region of northern Portugal (Tâmega). We have used a multi-stage complex sampling method, with clusters in three levels (county, group of schools and classes). The urine levels of As, Cd and Pb were measured by inductively coupled plasma-mass spectrometry (ICP-MS) according to the CDC method 3018.3. This is the first study simultaneously analyzing those three elements in urine from Portuguese children. The median levels (μg/L) were 0.14 for Cd, 0.47 for Pb and 29.11 for As. In general, the urinary concentrations of these toxic metals were below international reference limits (<2 μg/L for Cd, <4 μg/L for Pb and <35 μg/L for As), however concentrations of As were higher than 35 μg/L in 35% of children. These preliminary results reinforce the relevance for more detailed toxicological studies in school-aged children.