Scientists have developed a groundbreaking optical fiber sensor capable of detecting arsenic in drinking water at levels significantly below the World Health Organization's safety threshold. This innovation, unveiled by researchers at the Indian Institute of Technology Guwahati, allows for real-time monitoring of water safety, empowering households to safeguard their health.
Arsenic contamination poses a major environmental and public health challenge, impacting millions globally. It seeps into groundwater naturally, but human activities like mining and pesticide use exacerbate the issue. Lead author Sunil Khijwania emphasized the urgency of addressing arsenic exposure, stating, "Consuming arsenic-contaminated water can lead to severe health conditions, including arsenic poisoning and cancers of the skin, lung, kidney, and bladder."
The study, published in the journal Applied Optics, outlines how the sensor employs localized surface plasmon resonance to detect arsenic at concentrations as low as 0.09 parts per billion (ppb), far exceeding the WHO's limit of 10 ppb. Unlike traditional spectroscopy methods that require complex and costly equipment, this sensor is designed for routine use, delivering results in just 0.5 seconds.
To create the sensor, researchers coated the core of an optical fiber with gold nanoparticles and a specialized nanocomposite of aluminum oxide and graphene oxide, which selectively binds to arsenic ions. As light travels through the fiber, it interacts with these nanoparticles, facilitating the detection of arsenic through a measurable shift in wavelength.
Extensive testing confirmed the sensor's capability to reliably detect arsenic across a range of concentrations, achieving a resolution of ± 0.058 ppb. It demonstrated consistent performance over multiple days and aligned closely with results from the gold-standard inductively coupled plasma mass spectrometry (ICP-MS).
Real-world testing of drinking water samples from various locations in Guwahati validated the sensor's reliability. Khijwania noted, "These investigations established that the proposed optical fiber sensor offers a highly sensitive, selective, fast, cost-effective, straightforward, and easy solution for arsenic detection in real field conditions."
While the sensor is poised for practical applications, further advancements in optical sources and detectors are required for broader adoption. The research team envisions this technology as a step toward establishing a new standard in water quality testing, potentially saving lives by preventing arsenic exposure and ensuring safer drinking water for communities worldwide.