Removal cadmium and copper by Desmodesmus communis (Chlorophyta, Sphaeropleales) isolated from the high Andean wetland of Lake Junín (Peru)

Jara-Peña E.; Montoya H.; Huerta R.; Quinteros-Gómez Y.; Cano N.; Sánchez T.; Macedo D.; Gómez J. · Lilloa (2025) · DOI: 10.30550/j.lil/2274

Resumen

Lake Junín, considered the second largest lake in Peru, is a high Andean wetland. However, it is polluted by heavy metal residues and domestic waste entering through the Upamayo Reservoir. The objective of the study was to determine the effectiveness of Desmodesmus communis in extracting cadmium and copper from the water. Phytoplankton were obtained by horizontal trawling at for sampling stations. In the laboratory, the phytoplankton were seeded in Petri dishes containing agar and Bold Basal Medium (BBM). The microalgal colonies were then cultured in flasks containing liquid BBM. Metal removal was determined by measuring the difference in metal concentrations between the beginning and the end of the experiment. Microalgal biomass was calculated by measuring the difference in weight between the initial and final stages. To evaluate chlorophyll a content, unicellular cultures were sieved, and 90% acetone was added; the mixture was then centrifuged at 2500 rpm for five minutes. Absorbance readings were then taken in the chlorophyll supernatant at 630, 647, 664 and 750 nm using a spectrophotometer. Cell density was evaluated daily using a Neubauer chamber, and cell counting was performed under a microscope. The results show that D. communis evaluated with treatments of 40 mg L-1 of cadmium and 6 mg L-1 of copper achieved the highest removal rates of cadmium with 46.56% and copper with 24.79%, respectively. However, the exposure of D. communis to copper and cadmium treatments significantly decreased biomass, cell density and chlorophyll a content compared to the negative control, which obtained higher biomass (0.21 g L-1), a high chlorophyll a content (22.14 mg L-1), and the maximum cell density (192.05 × 10 5 cells ml -1). This shows that this microalga is tolerant to cadmium and copper, and its removal from water is possible due to bioaccumulation mechanisms.

Instituciones: Universidad Nacional Mayor de San Marcos