Pollution of Water for Domestic Use and Human Consumption, by Heavy Metals Pb, Cd, Cr, Zn and As,Derived from Mining Activity in Hidalgo Del Parral,Chihuahua, Mexico

摘要

Research was done with the objective of evaluating the quality of water supplied to the potable water system in Hidalgo Del Parral, which comes from two main supply sources: wells from Valle del Verano, which provide water to the east side of the city, and the Water Treatment Plant, which receives water from different mines and supplies the west side of the city. When this plant is overcome on its capacity of treatment, a part of the water from the mines is fed directly to the northwest part of the city. The metals lead (Pb), chromium (Cr), cadmium (Cd), zinc (Zn), and arsenic (As) were analyzed by atomic absorption (AA) technique, based in the United States Environmental Protection Agency (EPA) Method 7000B (Revision 2, February 2007). The digestion process was done according to the guidelines established in Method NMX-AA-051-SCFI-2001, Analysis of Water-Determination of Metals by Atomic Absorption, developed by the National Standardization Technical Committee for Environmental Protection (Mexico). The samples were collected from the following points: 13 wells and 2 re-pumping stations of Valle del Verano, the inlet and outlet of the Water Treatment Plant, and domestic faucets. The east side of the city, supplied by the wells of El Verano, is metal-pollution free. The water that comes from the mines contains high concentrations of As, Zn, Cd and Pb, with levels that can get to 0.12, 32.6, 0.26 and 3.5 mg/L, respectively. This water pollution generated by mining can be concluded from the high levels found in the domestic samples in which, for several points, the concentrations exceed the parameters set by the current guideline. According to the results, it is vital to set a plan of remediation for the water that comes from the mines, because there is a great risk for health in the consumption of this water.