Human Health Risk Assessment for Exposure to Potentially Toxic Elements in Polluted Rivers in the Ecuadorian Amazon

Abstract

Anthropogenic activities performed in the Ecuadorian Amazon have released potentially toxic elements (PTEs) into the rivers, causing severe environmental pollution and increasing the risk of exposure to the residents of the surrounding areas. This study aims to carry out a human health risk assessment using deterministic and probabilistic methods to estimate the hazard index (HI) and total cancer risk (TCR) related to multi-pathway human exposure to PTEs in polluted rivers. Concentrations of Al, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in surface water and sediment samples from rivers on the Ecuadorian Amazon were considered to assess the potential adverse human health effects. As a result, deterministic and probabilistic estimations of cancer and non-cancer risk through exposure to surface waters and sediments were above the safety limit. A sensitivity analysis identified the concentration of PTEs and the exposure duration (ED) as the two most important variables for probabilistic health risk assessment. The highest risk for receptors was related to exposure to polluted sediments through incidental ingestion and dermal contact routes. According to the deterministic estimation, the human health risk through ingestion of water was above the threshold in specific locations. This study reveals the potential health risk to which the population is exposed. This information can be used as a baseline to develop public strategies to reduce anthropogenic pollution and exposure to PTEs in Ecuadorian Amazon rivers.

An Integrative Approach to Assess the Environmental Impacts of Gold Mining Contamination in the Amazon

“…Exceedance of regulatory thresholds has been reported in several areas affected by mining exploitation in the Amazon basin [ 12 , 35 , 36 , 37 ]. Excessive metal concentrations in water and sediments, both those considered essential and nonessential to biological systems, can cause serious damage to aquatic life by affecting the reproductive physiology of fish and invertebrates, inducing carcinogenicity, genotoxicity, and causing adverse effects on the endocrine systems, such as liver necrosis and ultimately death [ 37 , 38 ].…”

An Integrative Approach to Assess the Environmental Impacts of Gold Mining Contamination in the Amazon

“…Exceedance of regulatory thresholds has been reported in several areas affected by mining exploitation in the Amazon basin [16,[38][39][40]. Excessive metal concentrations in water and sediments, both those considered essential and non-essential to biological systems, can cause serious damage to aquatic life by affecting the reproductive physiology of fish and invertebrates, inducing carcinogenicity, genotoxicity, and causing adverse effects on the endocrine systems, such as liver necrosis and ultimately death [9,40].…”

“…Moreover, the implemented techniques to extract gold ore include the unauthorized and indiscriminate use of Mercury (Hg) for the amalgamation process, which has led to high concentrations of this metal in freshwater ecosystems [6,7]. Hg release from mining poses high toxicity to aquatic organisms [8] and it is known to be a major driver for cancer and other diseases in local populations [9].…”

Perspective Chapter: Application of Environmental Epidemiology for Exposure and Health Risk Assessment

“…An example is how environmental epidemiology studies in health risk assessment, a study conducted in Czech Republic on potentially toxic elements pollution in agricultural soil health risk assessment revealed that of the total sample locations 6.04% non-carcinogenic and 13.05% carcinogenic to children [31]. According to Oyola et al [32] exposure to polluted sediments through incidental ingestion and dermal contact routes was the highest risk for receptors. Another study revealed that girls were more susceptible than boys to trace metal pollutants for both carcinogenic and non-carcinogenic risk [33].…”