Toxicity of acrylamide after degradation by conjugated (UV/H₂O₂) photolysis in microalgae

Acrylamide (AA) is routinely used in laboratories and industries, and its disposal is always a problem; consequently, offering an alternative for their treatment contributes to conducting research in a responsible way. Therefore, in this work, acrylamide solutions were degraded by ultraviolet radiation and hydrogen peroxide (H₂O₂), and their toxicity was evaluated using a Desmodesmus quadricauda microalgae growth assay. The AA solutions were exposed to different dosages of H₂O₂ and different exposure times to UV radiation. The degradation was evaluated by liquid chromatography, which allowed the identification of the acrylamide peak and subsequent by-product peaks. A 100% degradation of the 1.5 mg L^-1 AA solution with UV/H₂O₂ (0.034 g L^-1) was achieved in just 10 min. The by-products formed did not inhibit the growth of D. quadricauda microalgae. The number of D. quadricauda individuals that grew in acrylamide solutions exposed to 20 and 30 min of UV radiation, with 0.034 g L^-1 of H₂O₂, was very similar to the number of individuals that grew in the control solution. Thus, the treatment proposed in this work using H₂O₂ combined with ultraviolet radiation degraded acrylamide into by-products with reduced toxicity.