Distribution of chromium in whole blood and urine among general population in China between year 2009 and 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the chromium (Cr) levels in blood and urine among general population in China between 2009 and 2010, and thereby to analyze its prevalent features.</p><p><b>METHODS</b>From year 2009 to 2010, a total of 11 983 subjects of general population aged between 6 and 60 year-old were recruited from 24 districts in 8 provinces in eastern, central and western China mainland, by cluster random sampling method. The information about their living environment and health status were collected by questionnaire, and 11 983 blood samples and 11 853 urine samples were also collected. Inductively coupled plasma mass spectrometry (ICP-MS) was applied to test the Cr level both in blood and urine; and the Cr distribution in blood and urine among groups of population in different ages, genders and districts, were then analyzed.</p><p><b>RESULTS</b>Among general population in China, the geometric mean (GM) of Cr concentration in blood was 1.19 µg/L, with median at 1.74 µg /L and 95% percentile at 5.59 µg/L. The Cr concentration in blood among males and females were separately 1.18 µg/L and 1.20 µg/L(P > 0.05); while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 1.00, 1.22, 1.01, 1.40, 1.27 and 1.30 µg/L (P < 0.01), respectively; and the figures in populations from eastern, central and western China were 1.00, 1.70 and 1.98 µg/L (P < 0.01), respectively. Among general population, the GM of Cr concentration in urine was 0.53 µg/L, with median was lower than 0.42 µg/L and 95% percentile at 3.53 µg/L. The Cr concentration in urine among males and females were separately 0.52 µg/L and 0.53 µg/L (P > 0.05);while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 0.56, 0.60, 0.52, 0.50, 0.52 and 0.46 µg/L (P < 0.01), respectively;and the figures in populations from eastern, central and western China were 0.58, < 0.42 and 0.60 µg/L (P < 0.01), respectively.</p><p><b>CONCLUSION</b>The study reported the Cr levels in blood and urine among general population in China, and thereby provided basic data evidence for the following Cr biological monitoring studies in near future.</p>

Altered systemic iron metabolism in welders exposed to manganese / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the systemic changes of iron metabolism following manganese exposure.</p><p><b>METHODS</b>Ninety-seven welders and 91 workers with no history of exposure to manganese were recruited from the same factory in Beijing serving as the exposure group and the control group respectively. The welding rods used were type J422. The concentration of the manganese in the air of the work place was determined respectively with the national standard method. The serum iron and manganese, ferritin, transferrin and transferrin receptors were measured with the graphite furnace atomic absorption spectrophotometry and ELISA in both groups.</p><p><b>RESULTS</b>The permissible concentration-STEL of ambient Mn in welders' breathing zone ranged from 0.53 mg/m(3) to 2.19 mg/m(3), while the permissible concentration-TWA of ambient Mn was between 0.29 mg/m(3) and 0.92 mg/m(3) in the breathing zone of the workplace. Serum Mn and Fe concentrations in welders were about 1.40 times (P < 0.0l) and 1.2 times (P < 0.01), respectively, higher than those of control subjects. At the same time, the transferrin concentrations in serum were significantly higher (about 1.2 times, P < 0.05) in welders than in controls. In contrast, transferrin receptors were significantly lower (about 1.2 times) in exposed subjects than controls (P = 0.001). There was no difference in serum ferritin between the two groups (P = 0.112). Although there was no significant trend, the serum ferritin level was increased by 18% in comparison with that of the control. The abnormal percentage of serum Fe and Serum Mn in welders were 55.67% and 67.01% respectively, higher than those of control subjects. In addition, the correlations between all indicators and the duration of employment were not observed.</p><p><b>CONCLUSION</b>The long term exposure to the manganese can induce the disorder of the iron metabolism, which is found in the expression of increase of the serum iron and transferrin as well as the decrease of transferrin receptors.</p>