OBJECTIVEThis study aims to describe the distribution of 24 elements in urine of Shenzhen residents.

METHODSAccording to the principle of equal probability of selection method, in March 2011 to July, total 11 communities were chosen as the basic sampling unit in Shenzhen, with 1 to 2 communities in each of the municipal district. Then 75 families from each sampling unit were selected using systematic sampling method. In total, 2 200 subjects were chosen. 10-20 ml morning middle stream urine was collected, and then detected the concentration of Li, Be, Sr, Cd, Cs, Ta, Pb, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sn, Sb, Te, As, Se, Ru, Na, Mg, K, and analysed the discrepancies between gender and among age groups.

RESULTSIn those 24 elements, the concentration of Na was highest, the medians( 5th percentile (P 5), 95th percentile (P 95)) were 2 845.78 (920.29, 5 974.53) mg/L; Be was lowest, the result was 0.10(0.01, 0.58) µg/L. Except macroelements of Na (2 921.97 (985.14, 6 201.51) mg/L), Mg (48.20(8.23, 132.41) mg/L), K (2 323.20(683.98, 5 657.47) mg/L), the content of Rb was highest, 3.31(9.82, 7.83) mg/L, followed by Zn, 454.54(113.90, 1 320.00) µg/L, the content of V, Cr, Mn, Se, Tl was pretty low, the median of those elements all less than 1.00 µg/L. Statistically significant differences were found between genders and among age groups in Pb, Fe, Se (gender: Z values were 4.51, 2.53, 4.00, all P values were <0.05; age groups: H values were 55.67, 129.42, 18.46, all P values were <0.05). The medians(P5, P95) were 2.04 (0.57, 5.31), 202.88 (48.66, 564.90), 49.68 (14.34, 150.91) µg/L. The values of male were 2.22 (0.71, 5.33), 212 (47.50, 567.29), 53.42 (16.20, 160.63) µg/L. And the results of female were 1.95 (0.51, 5.24), 193.69 (49.52, 562.31), 46.62 (12.65, 142.80) µg/L; the values of less than 17 years old subjects were 1.66 (0.38, 3.77), 106.13 (26.69, 459.81), 51.86 (15.86, 169.71) µg/L; the results were 1.96 (0.52, 5.08), 209.83(52.87, 577.81), 54.14 (15.14, 144.11) µg/L in the group of 18 to 40 years old; in the 41 to 65 years old group, the values were 2.29 (0.78, 5.85), 228.15 (67.74, 615.16), 46.62 (13.95, 143.57) µg/L, the results were 2.19 (0.65, 5.69), 195.92(55.17, 490.24), 43.16 (12.42, 155.36) µg/L in 66 years old and more group.

CONCLUSIONAmong these 24 elements in urine of Shenzhen residents, the Na concentration was highest, while Be was lowest. Elements (Pb, Fe, Se) differed with the condition of gender and age groups. So we should take all these factors into account to establish their reference values.