Bioaccumulation characteristics and acute toxicity of uranium in Hydrodictyon reticulatum: An algae with potential for wastewater remediation.

The bioaccumulation characteristics and acute toxicity of uranium (U) to Hydrodictyon reticulatum were studied to provide reference for further mechanism and application research. According to an analysis using visual MINTEQ software, the pH change caused by the photosynthesis of H. reticulatum leads to U remaining mainly in the species of UO(OH). Fourier transform infrared spectrometer (FTIR) and transmission electron microscope (TEM) analysis showed that the bioaccumulation of U was related to the amino and carboxyl groups, resulting in cell wall damage. Using innovative cell staining microscopic observation techniques, U was mainly compartmentalized in vacuoles and pyrenoid; chlorophyll, soluble protein, dehydrogenase activity, and other physiological responses were closely related to the U stress concentration. Especially here, the change trend of the specific activity and specific growth rate of dehydrogenase was consistent, showing low concentration promotion and high concentration inhibition. Combined with the toxic response of the two, the half inhibitory dose for 72 h was determined to be about 30 mg L. When bioaccumulation equilibrium is reached at 72 h, the maximum tolerance concentration of U without affecting the easy collection characteristics of the algae is 30 mg L, and the maximum U bioaccumulation capacity was able to reach 24.47 ± 0.86 mg g by dry biomass.