Ecotoxicological analysis using Caenorhabditis elegans and Lactuca sativa to assess water quality in the Tunuyán river basin (Mendoza, Argentina)

MORÁBITO, J.; CLAVIJO, A.; ROSSEN, A.; MUNARRIZ, E.R.; KRONBERG, M.F.; CONFEGGI, A.; CALVO, D.; SYROKA, V.

Santos

Congreso; SETAC Latin America 12th Biennial Meeting; 2017

Water quality has long been analyzed using physicochemical and bacteriologicalparameters. Today scientific community agrees that to have an overall scenario of environmental impact is necessary to include ecotoxicological measurements. Both determinations are critical to establish a sustainable water management policy. In this regard, the European Water Framework Directive has established a common framework for sustainable and integrated management of water resources, in which sensitive environmental information, biological and ecological data play a leading role. In Argentina routine monitoring in general includes only standardized physicochemical and bacteriological parameters but toxicological properties are not considered. Seven sites were selected from Tunuyán River Basin (Province of Mendoza, Argentina). Monitoring were carried out from autumn 2015 to autumn 2016 to assess temporal variability. Two bioassays were used to assess toxicological characteristics of the water samples: the nematode Caenorhabditis elegans bioassays that use the relative growth as an end point and the Lactuca sativa elongation test.Jointly with these bioassays, physicochemical and bacteriological parameters were determined and a Water Quality Index based on the Canadian Council of Ministers of the Environment (CCMEWQI) according to the local normative for aquatic life protection was built. Both toxicological tests help to identify different spatio-temporal water qualities in the river basin. Multivariate statistical analyses (PCA) were developed. A toxicological ranking was established to quantify the water toxicity level using the results from C. elegans bioassays. Our results shown that most of the samples were in the highly toxic effect category for C.elegans, while L. sativa test seemed to exhibit no phytotoxic effect. Although a biostimulation effect on the radicle and hypocotyl elongation were observed in all samples specially in the lower basin monitoring sites. Comparison between the WQI and the toxicological ranking confirmed that traditional water quality studies do not predict potential toxic effects on living organisms. Our results verify that the bioassays show different sensibilities. C. elegans proved to be a more suitable tool to assess toxicity. Furthermore, they should be implemented in routine water quality monitoring to obtain a realistic scenario of water quality threats.