| application of 2 microbioassays for evaluating the pollution present in the xochimilco and lerma-santiago basins]. | pollution due to urban-agricultural and urban-industrial activities, on the enzymatic activity of two microorganisms was evaluated. the zones under study are located in the caltongo "embarcadero", in xochimilco, d.f., and the basin of lerma-santiago river, state of mexico. nine and ten stations were established, respectively. samples of water and sediment were taken, in order to determine their ph, salinity, organic matter, as well as the toxic effect produced on escherichia coli beta-galactosid ... | 1999 | 11001710 |