| Background: Electronic-waste or e-waste, refers to end-of-use electronic products including computers, printers, television sets, refrigerators, mobile phones, and toys. Guiyu, which is located in Shantou City, Guangdong province, is one of the largest e-waste recycling sites in the world. Guiyu is infamous for its involvement in primitive e-waste processing and recycling activities that cause severe damage to the environment and the health of local residents. Elevated levels of toxic heavy metals in air, road dust, soil and sediment of Guiyu had been found. Renal toxicity of Pb, Cd, Mn and Ni had been described. Retinol binding protein (RBP) and Beta-2-microglobulin (β2-MG) are freely filtered by glomerulus and reabsorbed by renal proximal tubules. Based on extensive clinical and experimental studies, elevated levels of these two biomarkers are generally accepted as valid tests for renal damage induced by environment chemicals in humans.Objective: This study investigates the effect of Pb, Mn, Ni and Cd on renal proximal tubular function in school children from an e-waste recycling town.Material and method: A total of 130 school children, aged 8 to 14 years, took part in this study. Sixty-one children living in Nanyang village of Guiyu were selected as subjects, and sixty-nine children from Liangying served as control. The concentrations of Pb and Mn in blood (PbB and MnB), Ni in serum (NiS) and Cd in urine (CdU) were determined by graphite furnace atomic absorption spectrometry with Zeeman background correction. Urinary RBP andβ2-MG were measured with ELISA methods. All urinary parameter assays were adjusted for creatinine in urine. Non-parametric analyses were used for data with skewed distributions and chi-square tests were used for categorical data. Spearman correlation analysis was conducted to evaluate the relationship between different parameters.Result: 1. Median PbB, MnB, NiS and CdU of children in Guiyu was 7.96μg/dL, 20.85μg/L, 5.12μg/L and 0.91μg/g creatinine respectively, while median PbB, MnB, NiS and CdU was 7.32μg/dL, 14.93μg/L, 2.97μg/L and 0.83μg/g creatinine respectively in the control group. PbB, MnB and NiS of children from Guiyu were higher than controls (P<0.05). Of school children in Guiyu, 21.31% had PbB > 10μg/dL, compared with 18.84% of children in Liangying (P>0.05). No significant differences in CdU were observed between the children in Guiyu and in the control group.2. Median urinary RBP of children was 63.03μg/g creatinine in Guiyu and 48.91μg/g creatinine in control. RBP in the Guiyu group was significantly higher than controls (P<0.05). Positive correlation between RBP and CdU were observed in boys (r=0.247, P<0.05).Conclusion: Higher PbB, MnB and NiS were found in school children living in the e-waste recycling town. Urinary RBP andβ2-MG showed increased excretion with increasing age in children. Elevated levels of Cd might cause damage to renal proximal tubule of boys. Primitive e-waste processing and recycling activities might influence renal proximal tubular function of school children.
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