Study of Arsenic Contamination in the Caplina Basin, Tacna, Peru: Arsenite and Arsenate Analysis Using Inductively Coupled Plasma Mass Spectrometry and High-Performance Liquid Chromatography

This study examines arsenic contamination in the Caplina Basin, Tacna, Peru, focusing on arsenic speciation and associated risks in surface waters. Arsenic concentrations were quantified using inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC). Total arsenic levels ranged from 0.0304 mg/L to 0.0730 mg/L across all monitoring points, exceeding the World Health Organization (WHO) limit of 10 µg/L (0.01 mg/L) for drinking water. Arsenite (As(III)), the most toxic and mobile species, reached levels up to 0.0154 mg/L, posing a significant concern at Point 7, characterized by acidic pH (3.82) and high conductivity (1456 µS/cm). Arsenate (As(V)), less toxic but predominant under alkaline conditions, peaked at 0.0260 mg/L at Point 6 (pH 8.42). Organic species such as dimethylarsenic acid (DMA) and monomethylarsenic acid (MMA) were also detected, indicating active methylation processes and anthropogenic influences. The risk assessment revealed carcinogenic risk values ranging from 2.56 × 10⁻⁵ to 6.28 × 10⁻⁵, below the USEPA threshold (1 × 10⁻⁴), but significant for prolonged exposure. Non-carcinogenic hazard quotient (HQ) values ranged from 0.09 to 0.21. These findings highlight severe public health implications and emphasize the urgent need for comprehensive strategies, including continuous monitoring, targeted treatment technologies, and community education, in order to guarantee water quality in vulnerable areas.