Laser-Induced Breakdown Spectroscopy for the Rapid Detection of Heavy Metals in Sargassum

A major influx of pelagic Sargassum spp. (sargasso) into the Atlantic coast of Florida has had a negative impact on the coastal environment, the local tourism and economy since 2011. Sargassum has a high capacity to absorb metals and recent studies using X-ray fluorescence (XRF) found high arsenic levels in sargasso on the Caribbean coast. As a result, leachates of sargasso cause toxic contamination of the sea and the groundwater if deposited in soil. A faster detection method uses laser-induced breakdown spectroscopy (LIBS) and can quickly dictate proper repurposing of the algae. Arsenic-free Sargassum can be repurposed as livestock feed and fertilizer. Yet, arsenic-containing Sargassum should not come in contact with humans and may be repurposed to produce sustainable aviation fuel and battery-grade graphite. Our research utilizes LIBS to detect and quantify the concentration of arsenic in Sargassum. With emission peaks at 189-m, 193-m and 278-nm, we use a special spectrophotometer with an optical fiber diffuser adapted to our current setup. Emission data will be collected for 20 samples from each of three beaches. The fast detection of arsenic with LIBS makes it an ideal technology for testing Sargassum samples in Florida beaches and deciding repurposing channels.