The rainwater chemistry within the Metropolitan Area of Monterrey (MAM) was studied during a one-year period (January 2019–January 2020) in seven sampling sites. The metal concentration of Zn, Fe, Cd, Cu, Ni, and Mn was analyzed in bulk samples and the toxicity potential (TP) was calculated for each metal. A canonical correspondence analysis (CCA) was applied to identify the relationship between environmental variables and metals concentrations. An average of 26.6 ± 10 mm of rainfall was obtained. A mean pH of 7.2 ± 0.3 and a mean electrical conductivity of 177.8 ± 8.7 µS cm⁻¹ were observed. The average concentration of metals in all sites follows a descending order of Fe> Zn > Mn > Cu > Ni > Cd. The university site shows the highest averages of Fe, Zn, Cu, and Mn, which is attributed to its proximity to the metallurgical industry. The TP value of Cd reflects a risk in all sites and Fe only for the Universidad, Obispado, Pastora, and Santa Catarina sites, using as a reference value the Environmental Protection Agency (EPA) Drinking Water Regulations and Mexican norm NOM-127-SSA1-1994. The CCA analysis showed that only Ni and Cd had a strong correlation with the environmental variable of relative humidity of air.

中文翻译：

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墨西哥东北部蒙特雷大都市区的大体积沉淀化学成分及其毒性潜力指数

在为期一年（2019年1月至2020年1月）的七个采样点研究了蒙特雷都会区（MAM）内的雨水化学。分析了散装样品中锌，铁，镉，铜，镍和锰的金属浓度，并计算了每种金属的毒性潜力（TP）。应用规范对应分析（CCA）来确定环境变量与金属浓度之间的关系。平均年降雨量为26.6±10 mm。平均pH值为7.2±0.3，平均电导率为177.8±8.7 µS cm ^-1被观察。所有位置的金属平均浓度均按Fe> Zn> Mn> Cu> Ni> Cd的降序排列。该大学的站点显示出Fe，Zn，Cu和Mn的最高平均值，这归因于其与冶金行业的距离。Cd的TP值反映了所有场所的风险，而仅Universidad，Obispado，Pastora和Santa Catarina场所的Fe表示风险，使用环境保护局（EPA）饮用水法规和墨西哥规范NOM-127-SSA1作为参考值-1994。CCA分析表明，只有Ni和Cd与空气相对湿度的环境变量密切相关。