Daily fluctuations and distribution of xenobiotics, nutritional and biogenic elements in human milk in Southern Poland.

Cadmium, lead, zinc, copper, calcium and magnesium levels were determined (with voltametric and AAS methods) in mature breast milk (obtained 12 weeks after birth) from women living in the Malopolska District, near Krakow, Poland. Milk was sampled from lactating women during a 14-day period three times a day: at 9:00 am, 3:00 pm, and 9:00 pm. A total of 210 milk samples was collected. In general we noticed the presence of differences both in the levels of Cd and Pb between milk samples taken from different women and statistically significant daily changes of Cd level in two cases and Pb level in three cases. We found daily fluctuations of trace elements levels in milk samples taken from two women in case of Zn, and from one woman in case of Cu. Among the nutritional elements magnesium and cadmium daily fluctuations were detected in isolated cases, respectively. The diferences in their levels among samples taken from different women were statistically significant. We found significant correlations between xenobiotics and two major nutritional elements and between xenobiotics and biogenic elements in breast milk samples. We found strong positive correlations between Cd and Ca (R = 0.220), Cd and Mg (R = 0.201), Cd and Zn (R = 0.279), Cu and Ca (R = 0.347), Cu and Mg (R = 0.084), Zn and Mg (R = -0.089) and negative correlation between Pb and Ca (R = -0.295). Our results suggest that xenobiotics such as Cd and Pb are transported to women's milk during lactation, and their presence has an important influence on trace and nutritional elements in breast milk. Breastfeeding mothers should avoid situations in which they run the risk of xenobiotics interactions.