Evaluation of Genotoxicity and Toxicity of Buenos Aires City Hospital Wastewater Samples

Abstract

The untrated wastewaters from health centers present a potential risk aquatic ecosystems because of the content of toxic and genotoxic chemicals. The composition of these wastewaters discharged to the urban sewer system present fluctua-tions generated by spatial and temporal variations in the discharges of citostatics, heavy metals (Pb, Cr, Hg), antibiot-ics, etc. In Buenos Aires city the Hospital effluents are discharged to the sewer system with no previous treatment in turn the wastes of the municipal sewage system are released to the Rio de la Plata, at a rate of 1,900 m 3 /day, with no treat-ment at all. This river is also the source of water for the plants that provide drinking water to the city. The objective of this paper was the study of the genotoxicity and toxicity from Hospital San Martin wastewaters. This General Hospital releases approximately 560 m 3 daily of effluents to the municipal sewer system, from. Sampling this effluent was per-formed seasonally, in this paper we report the results obtained in summer 2003, autumn 2004 samples. The determina-tion of toxicity was performed with the Pseudomonas fluorescens growth inhibition test and with the determination of mitotic index in Allium root tips. On the other hand the genotoxicity was studied with Saccharomyces cerevisiae D7 as-say and with the induction of chromosomal aberrations in Allium cepa test. Each sample was assayed either after steril-ization by filtration or as an XAD-2 resins extract. The samples of summer 2003 were toxic and genotoxic in the Allium test when were assayed at 100% and 50% v/v dilutions, genotoxicity in the Saccharomyces cerevisiae test was also de-tected at 100% and 10% v/v dilutions. The samples of autumn 2004 were no genotoxic, only toxicity for Saccaromyces strain was detected when raw effluents and 100X extracts were tested. None of the wastewaters samples assayed dem-onstrated toxicity in the Pseudomonas fluorescens test.