Periphyton bioaccumulation and biosorption potential: in-situ experiment in a eutrophic, mixohaline lake ecosystem (Tierra del Fuego, Argentina)

Periphyton is gaining relevance in bioremediation of polluted aquatic ecosystems because of its ubiquity and cost-effectiveness. The aim of this work was to study phosphorus and nitrogen bioaccumulation by periphyton grown on artificial substrata as a remediation strategy in two points (EB1 and EB2) in the Encerrada Bay, a mixohaline, eutrophic lake ecosystem in the City of Ushuaia (Tierra del Fuego, Argentina). In addition, the biosorption potential of the harvested periphytic biomass was assessed, using several organic molecules, including an emerging pollutant. Maximum nitrogen (N) accumulation was achieved after 4 months of colonization of the substrata for EB1 and 2 months for EB2 (1185.9 and 645.9 mg N m⁻², respectively). Also, maximum phosphorous (P) accumulation was achieved after 4 months of colonization of the substrata for EB1 and 2 months for EB2 (34.4 and 17.5 mg P m⁻², respectively). Once harvested, the dried biomass could be used in biosorption processes for different organic pollutants, as removal efficiencies were above 80% and 60% for dyes methylene blue and crystal violet, respectively, and almost 40% for the emerging pollutant oxytetracycline. These biosorption results are particularly interesting because it would suggest that it is a promising biomass reutilization strategy in the framework of circular economy.