The study looked at how different forms of arsenic affect the growth and chlorophyll levels of a type of algae called Scenedesmus obliquus. They found that high levels of As(III) had a stronger impact on slowing down the algae's growth compared to As(V). As the arsenic concentration increased, the chlorophyll levels in the algae decreased. Chlorophyll a was more sensitive to As(III) than As(V). The study also showed that arsenic negatively affected the algae's chlorophyll fluorescence parameters. Overall, the research suggests that arsenic inhibits the growth of Scenedesmus obliquus by affecting its photosynthetic system, with As(III) having a stronger impact on chlorophyll fluorescence than As(V).