Predicted intake of trace elements and minerals via household drinking water by 6-year-old children from Krakow (Poland). Part 4: Copper.

The aim of this study was to assess exposure of children to copper (Cu) from household drinking water (DW). DW samples were collected between 1997 and 2004 in approximately 650 households and pre-schools using a double-sampling method (morning - W1; evening - W2). The study group comprised approximately 300 children (5-7 years old) living in Krakow (urban, peripheral) and rural areas in southern Poland. Cu concentrations were determined by flame atomic absorption spectrometry. There was no significant relationship between the sampling period and Cu concentration, but statistically significant differences were found between urban and non-urban (rural, peripheral) sites and between morning and evening samples. Geometric means of Cu concentration in evening DW (95% confidence interval, in microg L(-1)) were 8 (1-110), 20 (1-274) and 12 (0-364) in urban, peripheral and rural sites, respectively. DW contamination after overnight standing was comparable in all sites (average increase approximately 20 microg Cu L(-1)). The adopted threshold of 100 microg Cu L(-1) was exceeded in evening DW by 3.6 and 15% in urban and non-urban households, respectively. Exceedance of the EC limit (2 mg L(-1)) was not significant. The mean predicted contribution of evening DW to Cu intake by children were 18-37 microg day(-1) or 0.8-1.6 microg kg(-1) bw day(-1) but were 2-3-fold higher for morning DW. The Polish RDA (1 mg Cu day(-1)) was exceeded for morning (evening) DW in 3.7 (0.2)% of children, with a mean intake of 159 (118)% of RDA. The observed copper levels and predicted intakes can be considered low and should not raise nutritional or toxicological concerns for the age group studied. Nevertheless, due to overnight contamination, the suggestion that the stagnant portion of drinking water should be discarded remains valid.