Detection of Arsenic at Micromolar Concentrations and Remediation of Arsenic from Drinking Water with a Bemliese Teabag

Arsenic (As) contamination in groundwater is a global public health concern, with many water sources across the globe exceeding the World Health Organization’s maximum permissible limit of 10 μg·L–1. Health issues related to As in groundwater are most prominent in South and Southeast Asia, where approximately 180 million people are exposed to dangerous As levels. To address this global health challenge, there exists a need for new, cost-effective methods to detect and remove As in water. Measurements of As levels in water are most typically performed in the field using colorimetric test strips, which are hard to use and not widely accessible. To address these ongoing detection challenges, we developed an accurate and affordable assay for the detection of As that involves the dissociation of NaAsO2 in the presence of HCl and KIO3 to form AsI3, which has a strong yellow color. Current methods to remove As from water mainly focus on wastewater treatment by reverse osmosis, which is expensive and not available to all communities vulnerable to As contamination. Here, Bemliese teabags embedded with magnetic iron oxide nanoparticles (MIO-NPs) and filled with 5 g of pulverized eggshells are shown to be a cost-effective and accessible way to remove >98% of As from a 50 mL solution initially containing 35 mg·L–1 NaAsO2 after 6 h of contact at near-neutral pH (∼7), reducing [As] to 0.69 mg·L–1. Taken together, the combination of new methods for As detection and removal provides scalable solutions to the global health challenges posed by As contamination in drinking water.