兰州市农村生活用水的水化学特征分析

摘要

The concentrations of major ions, salinity, total hardness, pH and electrical conductivity (EC) in domestic waters (cellar,well, spring, river, pool, tap waters) in rural areas of Lanzhou City were measured and compared with the background of Sanitary Standards for Drinking Water (GB5749-2006).Based on the results, domestic water salinity in rural areas of Lanzhou City was in the range of 0.14～2.72 g · L-l, with an average of 0.76±0.63 g · L-1.Significant differences were noted among the different domestic water types, with an order of decreasing salinity as follows: well water ＞ spring water ＞ pool water ＞ tap water ＞ river water ＞ cellar water.Average total hardness of the waters was 397.06±307.13 mg · L-1, with also a decreasing order as follows: well water ＞ river water ＞ tap water ＞ spring water ＞ cellar water ＞ pool water.With the exception of pool water, all the water samples had higher hardness than the background standards for drinking water.Ion concentrations, except potassium, were significant different in the water types.Well water had the highest ion concentration.Some well water samples had extreme concentrations of NO3--N, sulphate and chloride, far in excess of the background standards.But the average for all samples was lower than the standard.Significant differences (at P＜0.05) also existed in EC and pH among different water types.The following hydrochemical types were noted for different water types: HCO3-Cl-Ca-Mg for well water, HCO3-Cl-Ca for spring water, HCO3-Cl-SO4-Ca-Na for pool water, and HCO3-Ca-Mg for cellar, river and tap waters.%结合国家饮用水卫生标准(GB5749-2006),对兰州市不同类型农村生活用水(水窖水,井水、泉水、河水、水库水及自来水等)的主要阴阳离子,矿化度、总硬度、pH、电导率等指标进行了测定和分析.结果表明:各类水体矿化度为0.14～2.72 g·L-1,平均矿化度为0.76±0.63 g·L-1,不同水体存在显著差异性,其大小顺序为:井水>泉水>水库水>自来水>河水>水窖水;各类水体平均总硬度为397.06±307.13 mg·L-1,除水库水外,其余水体均有不同程度超标现象,其大小顺序为:井水>河水>自来水>泉水>水窖水>水库水;除钾离子外,其余阴阳离子在不同类型水体中的含量均存在显著差异性,井水中各离子含量高于其他类型水体;水体硝态氮、硫酸盐及氯化物含量在部分井水水样中有超标现象,但平均含量均低于国家标准限额;各类水体pH与电导率在0.05水平上存在显著差异性;水窖水、河流水及自来水水体的水化学类型以HCO3-Ca-Mg型为主,井水以HCO3-Cl-Ca-Mg型为主,泉水以HCO3-Cl-Ca型为主,水库水以HCO3-Cl-SO4-Ca-Na型为主.