HEALTH RISK ASSESSMENT OF TRACE AND TOXIC METALS IN DRINKING WATER OF THE COASTAL AREA OF TALUKA MIRPUR SAKRO, SINDH

Abstract

Contamination of drinking water with trace and toxic metals is a significant public health concern, particularly in coastal areas where natural and anthropogenic factors may elevate metal concentrations. This study assesses the levels of eight metals (Arsenic, Cadmium, Chromium, Cobalt, Manganese, Nickel, Copper, and Zinc) in drinking water samples collected from the coastal area of Taluka Mirpur Sakro, Sindh. A total of 30 water samples (MS-145 to MS-174) were collected and prepared using the wet digestion method. Analysis was performed using Atomic Absorption Spectrophotometry (AAS). The concentrations were compared with WHO permissible limits. Health risk assessment was conducted by calculating Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), and Cancer Risk for carcinogenic metals (As, Cd, Cr, Ni) using standard USEPA methodologies. The results revealed that concentrations of As exceeded the WHO limit (10 µg/L) in 24 out of 30 samples (80%), with values ranging from 5 to 75 µg/L. Co exceeded the WHO limit (0.1 mg/L) in 12 samples, with a maximum of 0.340 mg/L (MS-154). The EDI values ranged from 10⁻⁵ to 10⁻² mg/kg-day. THQ analysis indicated that all samples had THQ > 1 for multiple metals, with Co showing the highest THQ values (up to 32.38). The Hazard Index (HI) for all samples exceeded the safe level of 1, ranging from 3.35 to 34.85, indicating significant non-carcinogenic health risks. Total Cancer Risk (TCR) for all samples exceeded the USEPA acceptable limit of 1 × 10⁻⁴, ranging from 6.62 × 10⁻⁴ to 3.88 × 10⁻³, with As being the primary contributor. The drinking water of Taluka Mirpur Sakro is contaminated with toxic metals, particularly As and Co, posing significant non-carcinogenic and carcinogenic health risks to the local population. Immediate remediation measures and regular monitoring are recommended.

Keywords : Toxic metals, Arsenic, Estimated Daily Intake, Cancer Risk, Mirpur Sakro, Atomic Absorption Spectrophotometry.