HEALTH RISK ASSESSMENT OF HEAVY METALS IN KUANTAN RIVER BASIN, PAHANG

Abstract

Introduction: Industrialisation, urbanisation, and nearby human activities can lead to heavy metal pollution in the Kuantan River basin, posing a health risk. Objective: This quantitative secondary data analysis study aimed to estimate the health risk assessment (HRA) of the arsenic (As), lead (Pb), cadmium (Cd) and mercury (Hg) in the Kuantan River basin. Methods: All the secondary data on heavy metals concentration, physicochemical parameters and rainfall were obtained from the Department of Environment (DOE) and the Meteorological Department (MET), respectively. In reducing the uncertainties in health risk estimation, the Monte Carlo simulation technique was used to estimate the Hazard Quotient, HQ and Lifetime Cancer Risk, LCR of studied heavy metals via ingestion and dermal absorption. Sensitivity analysis (SA) was used to measure the most influential parameters on the estimated risk. Results: The results demonstrated that in 2017, the ascending order of mean concentrations of heavy metals was Pb > As > Cd > Hg. However, from 2018 to 2021, Cd and Hg consistently fell below the detection limit, leaving Pb > As as the dominant heavy metals during this period. All mean HQ values of studied heavy metals did not exceed the acceptable limit of one for both ingestion and dermal uptake. The mean LCR values for As via ingestion and dermal exposure remained within acceptable limits (1 x 10^-4). However, in 2017, the mean LCR value for Cd through dermal uptake (1.40 x 10^-4) slightly exceeded the acceptable level. Meanwhile, the worst-case predicted values at the 95^th percentile showed that the LCR values of As via ingestion route (all years), ranged from 1.48 x 10^-4 to 2.98 x 10^-4 and dermal uptake (except for 2019 and 2021), ranged from 3.80 x 10^-3 to 1.99 x 10^-4, exceeded the acceptable limit. SA demonstrated that the concentration of As and Cd had the greatest influence on HRA via the ingestion pathway and dermal uptake in 2017. Conclusion: It indicates As and Cd potentially increasing the chance of developing cancer. This study will help individuals in high-risk heavy metal exposure areas be more cautious and aid authorities in mitigating contamination.