Ecotoxicological response of algae to contaminants in aquatic environments: a review

Algae play a vital role in aquatic ecosystems, contributing to oxygen production and serving as a foundational component of the food chain. Environment stress and contamination can lead to harmful algal blooms, depleting oxygen levels and creating dead zones in water bodies. When exposed to contaminants such as industrial chemicals, pharmaceuticals, pesticides, heavy metals, and synthetic nano/microparticles, algae can exhibit adverse responses, disrupting the balance of aquatic ecosystems. Furthermore, environmental issues related to ecotoxicology responses of algae include the disruption of biodiversity and the loss of crucial habitats, which can lead to health issues. We reviewed the response of algae exposed to contaminants in the aquatic environments, including ecotoxicology and environmental stresses. The major points are: (1) The accumulation of polycyclic aromatic hydrocarbons in food chains and ecosystems and their uptake is widely revealed as a major concern for environmental health and human beings. (2) Bisphenol A can negatively impact algae by inhibiting biochemical and physiological processes, in which half maximal effective concentration varies from 1.0 mg L^-1 to 100 mg L^-1. (3) Though the level of per- and polyfluoroalkyl substances in the environment is generally low, ranging from ng L^-1 to mg L^-1, the combined contaminant exposure leads to significantly more significant toxic effects than individual compounds. (4) An exposure level of 1000ng L is unsafe for the ecosystems, and per- and polyfluoroalkyl substances could lead to algal growth inhibition, e.g., damage to the photosynthetic, inhibition of deoxyribonucleic acid replication, and reactive oxygen species metabolism. (5) The ecotoxicity of chemicals to algae is influenced by chemical, biological, and physical factors, creating complex effects at the biological community level. (6) This research indicated the importance of the ecotoxicology response of algae to contaminants, emphasizing the necessity for monitoring and strategic interventions to protect the sustainability of aquatic ecosystems.