Water quality assessment of the Rio Conchos, Chihuahua, Mexico

A baseline study was conducted to evaluate the overall quality of the Rio Conchos (Chihuahua, Mexico) and to identify those chemical parameters that can best represent the water quality in different segments of the river. Chemical analyses included the measurement of 62 elements at more than 100 sampling stations along the river, in addition to conventional field analyses (e.g., pH, conductivity). Concentrations of these elements are reported and water quality indicators were identified. Based on the element concentration patterns, the segment of the river in which the water quality is most endangered corresponds to that receiving irrigation drain returns near the confluence of the Rio San Pedro. Self-cleaning and dilution processes account for the improvement in water quality observed as the Rio Conchos approaches the Rio Grande. (C) 1999 Elsevier Science Ltd.