2.4. Statistical method
Statistical analyses were performed by the package of SPSS 11.5 for windows. The characteristics of T-Hg and Me-Hg concentrations were described in Mean±SD (standard deviation) and examined using descriptive statistics. Mean values were compared between different groups using independent-samples t-test to evaluate the differences. The correlation coefficients among U-Hg, hair T-Hg, and Me-Hg in each group were examined by the Pearson correlation analysis. The results of a statistical test were considered statistically significant if p