Effects of humic acid and suspended soils on adsorption and photo-degradation of microcystin-LR onto samples from Taiwan reservoirs and rivers

► The adsorption of MC-LR onto water sample with various aspects. ► The detailed studies on factors affecting the adsorption phenomenon. ► Elaborate simulation studies of adsorption and photo-degradation. This article covers the adsorption capacity of microcystin-LR (MC-LR) onto natural organic matter (NOM) or suspended solids of water samples from reservoirs (Emerald and Jade reservoirs) and rivers (Dongshan, Erhjen and Wukai rivers) in Taiwan to determine the fate, transport behavior and photo-degradation of microcystins in natural water systems. Langmuir adsorption and photo-degradation studies were carried out and the capability of samples for MC-LR adsorption was confirmed. Among these, samples collected from reservoir showed enhanced MC-LR adsorption than that of river samples and the greater adsorption behavior was always favored by larger content of organic matter and suspended particles in the system. It is obvious from the experimental results that the adsorption of MC-LR was influenced by suspended particles (turbidity), humic acid (HA), organic matter content and other pollutants. The effective photo-degradation of MC-LR was achieved using higher energy, lower wavelength (254nm) UV light within 60min. The presence of humic acid and turbidity affected the photo-degradation process. These data provide important information that may be applied to management strategies for improvement of water quality in reservoirs and rivers and other water bodies in Taiwan.