Evaluación de la calidad de las aguas del estero Limache (Chile central), mediante bioindicadores y bioensayos

Abstract

The water quality in the Limache stream was evaluated at five sampling stations during the pe- riod of low water flow. At each station, aquatic macroinvertebrates were collected and the following parame- ters were measured in situ: pH, conductivity, dissolved oxygen, and total dissolved solids. The biological oxy- gen demand, total phosphorus, and total nitrogen were determined in the laboratory. Water toxicity was deter- mined through toxicity bioassays with the microalga Pseudokirchrneriella subcapitata. Thirty-three macroin- vertebrate families were found and the dominant taxa were Dugessidae, Oligochaeta and Chironomidae. A significant correlation was found among the Family Biotic Index ChFBI, conductivity, and total dissolved solids (r = 0.92; p < 0.05). Species diversity was lowest, as was the growth rate of P. subcapitata, at the sta- tions with the greatest anthropogenic activity and in the discharge zone of a domestic wastewater treatment plant.