Water quality assessment in the region of Vale dos Sinos trough the alternative model Caenorhabditis elegans

Abstract

The determination of the condition of river water quality is critical to establishing sustainable water resource management policies. The use of bioindicators tests for the evaluation of water quality is a valuable tool, and the nematode C. elegans is described as a good organism to assess toxicological risks in aquatic and soil environments. The samples of water were collected in three stretches of the Paranhana and Ilha rivers (P1, P2 and P3) in November (spring) of 2018, January (summer) of 2019, April (autumn) of 2019, and August (winter) of 2019. The physic-chemical parameters were analyzed according to the standard methods (Standard Methods for the examination of Water and Wastewater 23rd edition). The nematode strains used are savage lineage N2 and were obtained through the Caenorhabidits Genetics Center (CGC) for the bioindicator test. The development evaluation was verified by the body surface area measurement of 20 nematodes which were quantified thru the ImageJ software. Most of the physic-chemical parameters were within the limits recommended by CONAMA, but aluminum, that presented values ten times higher than the recommended limit. Significant differences were observed in the nematodes development from all the samples when compared to the control group (p<0,001). The analysis of nematode development demonstrated that the bioindicator was sensitive to the research, showing that ecotoxicological assays are important for a more realistic scenario of threats to water quality, and C. elegans allows this assessment to be performed adequately.