[Study of distribution and influencing factors of lead and cadmium in whole blood and urine among population in 8 provinces in China].

OBJECTIVE: To evaluate the levels of lead (Pb) and cadmium (Cd) in blood and urine among general population in China, and thereby analyze their prevalent features. METHODS: A total of 18 120 subjects from general population aged 6-60 years were recruited from 24 districts in 8 provinces in eastern, central and western China mainland from 2009 to 2010, by cluster random sampling method. The blood samples and urine samples of these people were collected. The questionnaire survey was used to collect the information of the living environment and health conditions.Inductive coupled plasma mass spectrometry was applied to test the Pb and Cd levels in the samples, and the distribution of Pb and Cd in blood and urine for different ages, genders, areas and life habits were then analyzed. RESULTS: Among the general population in China, the geometric mean (GM) of blood Pb concentration was 34.9 µg/L; the GM of blood Pb in male and female groups were 40.1 and 30.4 µg/L (Z = -28.05, P < 0.05), respectively; the GM from eastern, central and western China were 31.2, 38.8 and 58.9 µg/L (χ(2) = 1 483.33, P < 0.05) , respectively. The GM of urine Pb of the whole population was 1.05 µg/L;while the GM in male and female groups were 1.06 µg/L and 1.05 µg/L (Z = -0.73, P > 0.05) , respectively;the values from eastern, central and western China were 0.76, 2.85 and 3.22 µg/L (χ(2) = 1 982.11, P < 0.05), respectively. The GM of blood Cd concentration among general population was 0.49 µg/L; and the values in male and female group were 0.60 and 0.41 µg/L (Z = -11.79, P < 0.05) , respectively; the GM from eastern, central and western China were 0.45, 0.65 and 0.67 µg/L (χ(2) = 69.87, P < 0.05), respectively; the GM of urine Cd concentration of the whole population was 0.28 µg/L, while the GM in male and female groups were 0.29 and 0.28 µg/L (Z = -3.86, P < 0.05), respectively; the values from eastern, central and western China were 0.29,0.42 and 0.18 µg/L (χ(2) = 402.76, P < 0.05), respectively. the Spearman's rank correlation coefficient for Cd in blood and Cd in urine was 0.22, for Pb in blood and Pb in urine was 0.21. Both the correlations were statistic significant (P < 0.05). CONCLUSION: The Pb and Cd levels in blood and urine were relatively higher among general population in China varying by gender and area. There were positive correlations between Pb and Cd levels in blood and those in urine.