Cu, Pb, or Cu+Pb, supplied as CuCl2 and PbCl2 (10, 25,
and 50 μM for both individual metal treatments and 10+10,
25+25, and 50+50 for combined metal treatments), totaling
four metal treatments. Stock solutions of 500 mL were prepared
in Erlenmeyer flasks. Four replicates were made for
each experimental group (16 Erlenmeyer flasks). Proposed
concentrations were based on recently analyzed data of
Rovai et al. (2013) and concentrations of heavy metals observed
in natural waters in the study area.