Chronic toxicity and environmental risk assessment of antivirals in Ceriodaphnia dubia and Raphidocelis subcapitata

Antiviral drugs are a class of medications used for treating viral infections. Due to their widespread use, especially in cases of pandemics and limited human metabolism, antivirals have been detected in multiple environmental matrices. This study aims to evaluate the chronic effects of acyclovir, efavirenz, lamivudine and zidovudine using Ceriodaphnia dubia and Raphidocelis subcapitata. The results with R. subcapitata showed the following toxicities: zidovudine (IC₅₀ = 5.442 mg L^-1) < acyclovir (IC₅₀ = 3.612 mg L^-1) < lamivudine (IC₅₀ = 3.013 mg L^-1) < efavirenz (IC₅₀ = 0.034 mg L^-1). The results of the chronic bioassay with C. dubia demonstrated that zidovudine is the least toxic (EC₅₀ = 5.671 mg L^-1), followed by acyclovir (EC₅₀ = 3.062 mg L^-1), lamivudine (EC₅₀ = 1.345 mg L^-1) and efavirenz (EC₅₀ = 0.026 mg L^-1). Both species have been shown to be sensitive to efavirenz. A risk quotient (RQ) was calculated, and efavirenz had an RQ greater than 1 for both species, and lamivudine had an RQ greater than 1 for C. dubia, representing a high ecological risk for these organisms. Antivirals pose a significant environmental risk to aquatic organisms and should be taken into consideration in future monitoring of water sources.