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

Samantha Jiménez-Oyola,Kenny Escobar Segovia,Marcelo Ortega,Bryan Salgado,María-Jesús García-Martínez,Iker García-Garizabal,David Bolonio

doi:10.3390/w13050613

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.

Highlights

Toxic elements (PTEs), including trace elements and heavy metals, are naturally occurring substances in the environment; the anthropogenic activities in some regions have increased their concentration [1,2]
This study provides preliminary information on the health risk of Potentially toxic elements (PTEs) for adults and children, both of which are river users in the Ecuadorian Amazon
The highest risk for adults and children was related to exposure to polluted sediments through incidental ingestion and dermal contact routes

Summary

Introduction

Toxic elements (PTEs), including trace elements and heavy metals, are naturally occurring substances in the environment; the anthropogenic activities in some regions have increased their concentration [1,2]. Several studies have reported that exposure to PTEs can cause various acute and chronic health hazards [6,7]. These pollutants are released into many environmental media and may enter the human body; inhabitants of polluted areas, mainly children, are exposed to PTEs from several different sources and pathways [8,9,10]. Cd, Cr, Hg, and Pb are systemic non-cancerous, and can produce adverse health effects even at low levels of exposure [12]

Objectives

Methods

Results

Discussion

Conclusion