Water quality assessment of the Rio Conchos, Chihuahua, Mexico

A baseline study was conducted to evaluate the overall quality of the Rio C onchos (Chihuahua, Mexico) and to identify those chemical parameters that c an best represent the water quality in different segments of the river. Che mical analyses included the measurement of 62 elements at more than 100 sam pling 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 concentrati on patterns, the segment of the river in which the water quality is most en dangered corresponds to that receiving irrigation drain returns near the co nfluence of the Rio San Pedro. Self-cleaning and dilution processes account for the improvement in water quality observed as the Rio Conchos approache s the Rio Grande. (C) 1999 Elsevier Science Ltd.