过夜自来水初流水微量元素含量变化

目的 探讨过夜自来水初流水微量元素含量变化。方法 采集自铸铁及镀铬两种水龙头流出的过夜自来水（贮存于镀锌供水铁管10h)的初流水和中段水,采用原子吸收分光光度法测定铜,锰,铁,锌含量,并分析了其变化趋势与出水量的关系。结果 自两种水龙头流出的过夜自来水初流水和中段水铜锰含量无显著差异,且均符合生活饮用水标准。铸铁水龙头初流水铁含量以及镀铬水龙头初流水锌含量均高于相应中段水,且均超过生活饮用水标准,其变化均与出水量呈负相关（rZn=-0.938,rFe=-0.936,P均＜0．01）。出水3L时,铁锌含量基本生活饮用水标准。结论 水龙头材质影响初流水铁锌含量,给3L的初流水不宜饮用,建议采用更卫生安全的供水管材和水龙头。

Variations of Contents of Trace Elements in First Section of Tap Water Stagnating in Pipe Over Night

Objective To study the variations of the contents of trace elements in first section of tap water stagnating in pipe over night. Methods The first and middle sections of tap water stagnating in galvanized iron pipe for water supply over night for about 10 hours flowing through an iron tap and a chromed tap were sampled and determined for the contents of copper, manganese, iron and zinc by atomic spectrophotometry. The relationship between the variations of contents of four elements and the flow capacity was analyzed also. Results The contents of copper and manganese in the first section and middle section of tap water stagnating in pipe over night accorded with the sanitary standard for drinking water (SSDW), and revealed no significant differences between the first and middle section of tap water. The contents of iron in first section of tap water flowing through an iron tap and the contents of zinc in first section of tap water flowing through a chromed tap both exceeded the SSDW and revealed higher levels respectively compared with those in the related middle section of tap water. The levels of iron and zinc negatively correlated with the flow capacity (r Zn=-0.938,P<0.01,r Fe=-0.936,P<0.01). Iron and zinc revealed levels accorded with those ruled by SSDW in the samples collected at a flow of first 3 L of first section. Conclusion The contents of iron and zinc in first section of tap water stagnating in pipe over night could be influenced by the type of tap. About first 3 L of first section of tap water stagnating in pipe over night was not safe for drinking. It was suggested that more sanitary and safe water supply pipe and tap should be applied.