Determination of low-level arsenic, lead, cadmium and mercury concentration in breast milk of Hungarian women

Breast milk was taken at different stages of lactation from 27 healthy lactating women living in Budapest and its metropolitan area with ages comprising between 25 and 41 years who exclusively breastfed their full-term newborns. Samples were subjected to microwave-assisted (MW) acid digestion in PTFE vessels containing quartz microvials. After fine-tuning of the MW-assisted acid digestion method by determination of total organic carbon content of the digested samples, the volume ratio for sample: 67% by weight HNO3 : 30% by weight H2O2 solutions = 1 : 2 : 1 proved to be suitable for determination of As, Cd and Pb by inductively coupled plasma sector field mass spectrometer. Mercury concentration was <0.4 mu g/L in all samples. The order of Cd, As and Pb mean concentration in the samples were 0.188 +/- 0.071 mu g/L < 0.41 +/- 0.20 mu g/L < 1.74 +/- 0.77 mu g/L, respectively. Mean and median concentration of As and Pb data generally grouped into two-week intervals of lactation decreased by about 25-35% after two months. Moreover, statistically significant increase was observed for Pb concentration with the age of the mothers according to paired sample t-test almost 20 years after the prohibition of the marketing of leaded gasoline in the European Union and about 40 years after the ban on Pb pipes for drinking water delivery in Hungary (Pearson's correlation coefficient 0.8285; at p < 0.05). However, according to our dietary intake estimations, no other threat for newborns fed by exclusive breastfeeding was detected.