Total and inorganic arsenic biosorption by Sarcodia suiae (Rhodophyta), as affected by controlled environmental conditions

Abstract

Temperature, light intensity (LI), adsorbent source and concentrations are key external factors affecting algal metabolism and thus metal-accumulation mechanisms. In this study, the alga Sarcodia suiae was exposed individually to a range of temperature (15, 20, and 25 degrees C), and LI (30, 55, and 80 timol photons m(-2) s(-1)) at initial arsenate [As(V)] concentration (;conc: 0, 62.5, 125, 250, and 500 mu g L-1) conditions, to investigate the variations of total arsenic (TAs) and inorganic arsenic (iAs) accumulation mechanisms in the algal body. Temperature significantly affected TAs and arsenite [As(III)] production and maximum absorption were obtained at 15 degrees C, which was significantly stimulated by increasing ;conc. However, the temperature did not affect As(V) production. LI had no significant effect on TAs or iAs production, although maximum absorption was estimated in 80 timol photons m(-2) s(-1). The iAs component of TAs was much greater in the temperature experiment particularly under 250-500 mu g L-1 (i)conc than in the LI experiment, is witnessed. Overall, temperature and (i)conc strongly affected As accumulation. The predominant iAs produced was As(III), regardless of temperature or LI, suggesting that the alga favored As(III) biosorption. Also, visible effects on the morphology of this alga were adverse with increased concentration and environmental factors did affect the difference somewhat. Our results contribute to improving our understanding of the effects of the tested factors on As cycling, which is necessary for maximizing biosorption of algae if utilized for bioremediation studies as well as in the wastewater treatment implementation approach in the environment. (C) 2020 Elsevier Ltd. All rights reserved.