Health risk assessments of arsenic and toxic heavy metal exposure in drinking water in northeast Iran

Tafaghodi Mohamad,Maryam Fakhari,Batoul Zarif Garaati Oftadeh,Seyedeh Belin Tavakoly Sany,Hosein Shamszade,Hosein Alidadi

doi:10.1186/s12199-019-0812-x

Abstract

BackgroundArsenic and heavy metals are the main cause of water pollution and impact human health worldwide. Therefore, this study aims to assess the probable health risk (non-carcinogenic and carcinogenic risk) for adults and children that are exposed to arsenic and toxic heavy metals (Pb, Ni, Cr, and Hg) through ingestion and dermal contact with drinking water.MethodIn this study, chemical analysis and testing were conducted on 140 water samples taken from treated drinking water in Mashhad, Iran. The health risk assessments were evaluated using hazard quotient (HQ), hazard index (HI), and lifetime cancer risk (CR).ResultsThe results of the HQ values of arsenic and heavy metals for combined pathways were below the safety level (HQ < 1) for adults, while the HI for children were higher than the safety limit in some stations. Likewise, Cr showed the highest average contribution of HItotal elements (55 to 71.2%) for adult and children population. The average values of total carcinogenic risk (TCR) through exposure to drinking water for children and adults were 1.33 × 10−4 and 7.38 × 10−5, respectively.ConclusionOverall, the CRtotal through exposure to drinking water for children and adults was borderline or higher than the safety level of US EPA risk, suggesting the probability of carcinogenic risk for the children and adults to the carcinogenic elements via ingestion and dermal routes. Therefore, appropriate purification improvement programs and control measures should be implemented to protect the health of the residents in this metropolitan city.

Highlights

Heavy metals and arsenic contamination in drinking water poses a serious threat to human life because of their toxicity, bio-accumulative nature, and persistence in the environment [1,2,3]
The results of the hazard quotient (HQ) values of arsenic and heavy metals for combined pathways were below the safety level (HQ < 1) for adults, while the hazard index (HI) for children were higher than the safety limit in some stations
Studies elsewhere showed that several factors such as source water, pipeline corrosion, poor purification system, and water dynamics affect the concentration of heavy metals in pipeline drinking water [34, 35]

Summary

Introduction

Heavy metals and arsenic contamination in drinking water poses a serious threat to human life because of their toxicity, bio-accumulative nature, and persistence in the environment [1,2,3]. The greatest threat of toxic heavy metals and arsenic is reported in the drinking water and groundwater of several countries, including Mexico, Saudi Arabia, India, Bangladesh, China, Chile, Thailand, and Iran [1, 7]. In the last 10 years, data on heavy metal contamination of groundwater in most rural areas of India showed that the average concentrations of As, Mn, Cr, Pb, Ni, and Zn in drinking water exceeded the WHO guidelines, which was linked to the pharmaceutical, paint, pesticide and fertilizer industries [11, 12]. This study aims to assess the probable health risk (non-carcinogenic and carcinogenic risk) for adults and children that are exposed to arsenic and toxic heavy metals (Pb, Ni, Cr, and Hg) through ingestion and dermal contact with drinking water

Objectives

Methods

Results

Conclusion