Prospecting for Phytotoxicity and Enzymatic Modulation of Waters from Springs in the Surroundings of Campo Mourão, State of Paraná, Brazil, in Lactuca sativa L.

The Rio do Campo and Rio Km 119 rivers are under constant human pressure. Thus, it is necessary to assess the adverse effects caused by waters of these rivers to living organisms. Phytotoxicity and enzymatic modulation of waters from eight sites was evaluated against Lactuca sativa L.—five located in Rio do Campo (P1, P2, P3, P4, and P5) and three located in Rio Km 119 (P6, P7, and P8)—strategically making up the surroundings of Campo Mourão. For every site, two samplings were made in 2019, one during the dry season (first sampling) and another during the rainy season (second sampling). Waters from P2 and P8, collected in the dry season reduced the seed germination rate. With the exception of P7 in sampling 1, waters from the other sites, in both seasons considered, significantly inhibited radicle elongation. In the dry season, there was an increase in CAT activity, mainly in roots exposed to waters from P3 and P7. In the rainy season, there was a reduction in the activity of this enzyme in roots, caused by waters from P1, P2, P4, P6, and P7. Except for P3 in the first sampling, roots exposed to waters from the eight sites, in samplings 1 and 2, had inhibition in SOD activity. Therefore, waters from the eight sites caused significant phytotoxicity and oxidative stress to L. sativa. These results complement and corroborate studies to assess the toxicity of waters of the Rio do Campo and Rio Km 119 rivers present in the literature. The imminent intervention of the public management of Campo Mourão and of the State government is necessary in the urban and agricultural human activities carried out in these springs, given the significant degradation and putting the survival of different species at risk.