Spatial distribution and health risk assessment of As and Pb contamination in the groundwater of Rayong Province, Thailand

Wiyada Nilkarnjanakul; Pensri Watchalayann; Srilert Chotpantarat

doi:10.1016/j.envres.2021.111838

Spatial distribution and health risk assessment of As and Pb contamination in the groundwater of Rayong Province, Thailand

Environ Res. 2022 Mar;204(Pt A):111838. doi: 10.1016/j.envres.2021.111838. Epub 2021 Aug 20.

Authors

Wiyada Nilkarnjanakul¹, Pensri Watchalayann², Srilert Chotpantarat³

Affiliations

¹ Faculty of Public Health, Thammasat University, Rangsit Campus, Pathum Thani, 12121, Thailand. Electronic address: wiyada.n@fph.tu.ac.th.
² Faculty of Public Health, Thammasat University, Rangsit Campus, Pathum Thani, 12121, Thailand. Electronic address: pensri.watchalayann@gmail.com.
³ Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Research Program on Controls of Hazardous Contaminants in Raw Water Resources for Water Scarcity Resilience, Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Thailand; Research Unit Control of Emerging Micropollutants in Environment, Chulalongkorn University, 10330, Thailand. Electronic address: Srilert.C@Chula.ac.th.

PMID: 34425115
DOI: 10.1016/j.envres.2021.111838

Abstract

This study investigates the presence of arsenic (As) and lead (Pb) in groundwater and their spatial distribution in Ban Khai District, Rayong Province, Thailand. Forty groundwater samples were collected at different locations in the dry and wet seasons during March and August of 2019, respectively. The hydrochemical facies illustrate that the major groundwater types in both seasons mainly consisted of Ca-Na-HCO_3, Ca-HCO₃-Cl and Na-HCO₃ types. The concentration of As ranged from <0.300 to 183.00 μg/L, accounting for 22% (18 of 80 samples), exceeding the WHO guidelines of 10 μg/L. The spatial distribution of As was distinctly predominant as a hot spot in some areas during the wet season. The wells may have been contaminated from human activity and thus constituted a point source in the adjacent area. For Pb, its concentration in all the wells were not exceeded 10 μg/L of the WHO guidelines, appearing as a background concentration in this area. Most of the wells were shown to be in an oxidation state, supporting As^V mobility. Moreover, the area also had a nearly neutral pH that promoted As^V desorption, while the presence of undissolved Pb in the aquifers tended to increase. Furthermore, chemical applications to agricultural processes could release the As composition into the groundwater. The health risk resulting from oral consumption was at a higher risk level than dermal contact. The non-carcinogenic risk affecting the adult population exceeded the threshold level by approximately 27.5% of the wells, while for the children group, the risk level was within the limit. Total cancer risk (TCR) of adult residents exceeded the acceptable risk level (1 × 10^-6) in all wells, causing carcinogenic health effects. Therefore, health surveillance is important in monitoring the toxic effects on the local residents who use groundwater from these contaminated wells. Furthermore, a sanitation service and an alternative treatment of the water supply will be needed, especially in wells with high As levels.

Keywords: Arsenic species; Drinking groundwater; Groundwater contamination; Health risk assessment; Thailand.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Arsenic* / analysis
Child
Environmental Monitoring
Groundwater*
Humans
Lead
Risk Assessment
Thailand
Water Pollutants, Chemical* / analysis
Water Pollutants, Chemical* / toxicity

Substances

Water Pollutants, Chemical
Lead
Arsenic