**Evaluation of the E**ff**ect of Gold Mining on the Water Quality in Monterrey, Bolívar (Colombia)**

**Alison Martín 1,2, Juliana Arias 1, Jennifer López 1, Lorena Santos 1, Camilo Venegas 1, Marcela Duarte 3, Andrés Ortíz-Ardila 4, Nubia de Parra 3, Claudia Campos <sup>1</sup> and Crispín Celis Zambrano 2,\***


Received: 7 August 2020; Accepted: 4 September 2020; Published: 10 September 2020

**Abstract:** Gold mining uses chemicals that are discharged into rivers without any control when there are no good mining practices, generating environmental and public health problems, especially for downstream inhabitants who use the water for consumption, as is the case in Monterrey township, where the Boque River water is consumed. In this study, we evaluate Boque River water quality analyzing some physicochemical parameters such as pH, heavy metals, Hg, and cyanide; bioassays (*Lactuca sativa, Hydra attenuata*, and *Daphnia magna*), mutagenicity (Ames test), and microbiological assays. The results show that some physicochemical parameters exceed permitted concentrations (Hg, Cd, and cyanide). *D. magna* showed sensitivity and *L. sativa* showed inhibition and excessive growth in the analyzed water. Mutagenic values were obtained for all of the sample stations. The presence of bacteria and somatic coliphages in the water show a health risk to inhabitants. In conclusion, the presence of Cd, Hg, and cyanide in the waters for domestic consumption was evidenced in concentrations that can affect the environment and the health of the Monterrey inhabitants. The mutagenic index indicates the possibility of mutations in the population that consumes this type of water. Bioassays stand out as an alert system when concentrations of chemical contaminants cannot be analytically detected.

**Keywords:** bioassays; gold mining; health risk; mercury; microbiological indicators; mutagenicity; toxicity
