**5. Conclusions**

The results obtained with the three toxicity indicators reveal that *H. attenuata* does not present sensitivity to toxic substances present in this type of water, so its use for this purpose is not recommended. On the other hand, *D. magna* showed sensitivity even in diluted samples as well as *L. sativa*, which showed growth inhibition and excessive growth in different concentrations of the analyzed water, inclusive of waters with pollutant concentrations below the detection level. The Ames test shows an increase in the revertants indicating the possibility of mutations in the population that consumes this type of water, which is correlated with the results of the mutagenicity test that showed a mutagenic effect in the five stations evaluated with both strains used in the study. The highest mutagenic index was found in the water sample taken from the house sampling station. The concentration of bacteria in the water exceeded the limits allowed by Colombian regulations, creating a health risk, also with an alert call to the presence of possible pathogenic viruses, and the risk that they imply for the inhabitants of Monterrey due to somatic coliphage levels determined.

This research recognizes the potential use of bioassays to evaluate the toxic effects generated by chemical wastes produced by gold mining and discharged into surface waters. The use of animal and plant models is recommended to evaluate said effects on the environment and public health and infer the damages that until now have not been sufficiently evaluated having as correlation factors physicochemical and microbiological parameters.

Finally, this research generated data that contribute to the knowledge of the effects caused to the environmental and public health by illegal and legal mining carried out with bad practices in emerging countries with inefficient controls of this type of activity. These assays used can help sanitation organizations in different countries to take preventive actions on this issue

**Author Contributions:** All authors contributed to all features of the paper. A.M., J.A., J.L., L.S., C.V., A.O.-A., and M.D. were involved in the sampling and analysis of bacteria, coliphages, bioassays, and physicochemical determinations. C.C. and C.C.Z. conceived the idea for the research and contributed to the development of the project by obtaining economic resources. C.C., N.d.P., and C.C.Z. provided consultation and interpretation of the results and contributed to writing the manuscript. C.V., A.M., and J.L. edited the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research and article publication was funded by Pontificia Universidad Javeriana, Bogotá, Colombia. Grant number 0005746 and 0008469.

**Acknowledgments:** The authors would like to acknowledgment the residents of Monterrey Sur de Bolívar, Colombia, and Programa de Desarrollo y Paz del Magdalena Medio by the logistical support in sampling.

**Conflicts of Interest:** The authors declare no conflict of interest.


*Water* **2020** , *12*, 2523

**Appendix**

 **A** Zinc (Zn) (mg/L) mg/L: milligram per liter; S: sampling, the numbers 1S, 2S, and 3S correspond to the month of July, September, and December in which the sample was taken; <: less than the limit of

quantification;

 n: is the number of samples.

<1.0 × 10−3

<1.0 × 10−3

<1.0 × 10−3

<1.0 × 10−3

<1.0 × 10−3

<1.0 × 10−3

3.0
