Besides, these authors evaluated concentrations of nutrients and other chemical compounds such as nitrates, ammonia, sul¬fates, H2S, Fe, Cu, among others (data not shown).
Roldan (2003) reported pH values ranging from 6.1 to 7.4 for 14 Colombian reservoirs. Other data were as follow: 6.0-20 mg L-1 alkalinity, 14-90 pS cm-1 conductivity, 5.0-50mgL_1 total hardness, and 0.01-0.08 mg L_1 phosphates. In our study, we found higher values for alkalinity (range 17.95-39.38 mg L_1) and phosphates (0.01-0.30 mg L_1), and values slightly higher for conductivity (48.73-67.06 pScm-1) and pH (6.42-8.48) than those reported by that author.