Ecological and Health Risk Assessment of Potential Toxic Elements from a Mining Area (Water and Sediments): The San Juan-Taxco River System, Guerrero, Mexico

Abstract

The San Juan-Taxco River system is situated in the Taxco mining district, which is a well-known international producer of silver, jewelry and precious metal handicrafts. The population and biota in the area have been affected by inappropriate disposal of anthropogenic activities that pollute the hydric resources and threaten their health and sustainability, since the inhabitants use the groundwater and river water for human consumption, domestic water supply and irrigation. This study was conducted to assess the pollution in the river system, human health implications and ecological risk in the aquatic environment (groundwater, surface water and superficial sediment). This evaluation was done on the base of hydrochemical, textural, mineralogical and geochemical analysis supported by calculation of human health risk using chronic daily intake (CDI), hazard quotient (HQ) and hazard index (HI) with environmental and geochemical indices for ecological risk evaluation. The health risk assessment indicated increasing non-health carcinogenic risk to the exposed population to the river water and dug wells (HI > 1), and thus, these resources are not recommended for human consumption, domestic activities and prolonged ingestion. The results demonstrated a high degree of pollution due to toxic elements and geochemical indices. The Pollution Load Index indicated potential risk that will cause harmful biological effects in the riverine environment.

Could the presence of ferrihydrite identified in a riverbed impacted by mining leachates be linked to the reduction in the Heavy Metals Contamination Index?

“…This methodology is characterized by the identification and analysis of toxic elements and their adverse effects at a specific time and the estimation of their risk level. The calculation of chronic daily intake (CDI) is based on equations 4 and 5, as the two primary routes of pollutant entry through ingestion or dermal absorption, according to Salcedo et al, (2022).…”

Socio-Environmental Risks Linked with Mine Tailings Chemical Composition: Promoting Responsible and Safe Mine Tailings Management Considering Copper and Gold Mining Experiences from Chile and Peru

“…In the aquatic environment, heavy metals can be very toxic to aquatic life and the human population due to their persistence, toxicity, non-degradability, bioaccumulation, and biomagnification in the food chain [ 81 , 82 ]. Heavy metals can enter the human body through the oral, inhalation, and dermal contact routes [ 83 ].…”

Heavy Metal Contamination and Ecological Risk Assessment in the Sediment Cores of the Wetlands in Southern Thailand

“…The ecological risk index (R¡) was calculated to assess the degree of heavy metal pollution in sediment cores of the Khuan Khi Sian wetland based on the toxicity of heavy metals and the response of the environment. The Ri was calculated according to Equation (3) [41]:…”