Arsenic and heavy metals contamination by effluent dam rupture in a subtropical coastal lagoon.

Dam accidents, often resulting from inadequate structural monitoring, pose significant environmental risks. In southern Brazil, the rupture of an evaporation-infiltration lagoon released over 500,000 m of treated domestic effluent into a coastal lagoon, raising concerns about potential contamination from nutrients and heavy metals. This study aimed to (1) assess the environment's self-purification capacity regarding dissolved nutrients, (2) determine total heavy metal concentrations in water and sediments throughout the coastal lagoon using inductively coupled plasma mass spectrometry, (3) correlate variables influencing heavy metal availability to identify potential sources, and (4) evaluate environmental risks by comparing concentrations to established water and sediment quality guidelines.