Freshwater Sponges Reveal Heavy Metal Pollution in Louisiana Waters

Heavy metals are persistent pollutants in aquatic systems, with their toxicity influenced by site-specific factors such as pH, temperature, salinity, and organic matter. In Louisiana, water bodies often contain high levels of dissolved and particulate organic matter, elevated temperatures, and multiple freshwater sponge species, creating unique conditions for metal accumulation. To assess heavy metal contamination, water, sediment, and freshwater sponges were collected from multiple sites in Louisiana. Metal concentrations were quantified using inductively coupled plasma mass spectrometry (ICP-MS), and laser ablation ICP-MS (LA-ICP-MS) was applied to sponge tissues to map spatial metal distribution. Results indicate that sediments and sponges consistently contain higher metal concentrations than surrounding water, confirming the role of sponges as efficient passive samplers. LA-ICP-MS revealed localized patterns of metal accumulation within sponge tissues, providing detailed insight into uptake mechanisms and tissue-specific bioavailability. These findings demonstrate that freshwater sponges effectively reflect the heavy metal burden of Louisiana aquatic ecosystems and can serve as bioindicators to complement conventional monitoring approaches. Integrating ICP-MS and laser ablation techniques offers a powerful method for evaluating bioavailable metals, supporting improved water quality assessment, environmental management, and the development of aquatic life criteria in Louisiana freshwater and brackish systems.