Vertical Profiles of Acid-Volatile Sulfide and Toxicity of Heavy Metals in a Municipal Polluted River in PRD, China

AVS (Acid-volatile sulfide) and SEM (Simultaneously Extracted Metals) profiles are presented for a 100cm-sediment core taken in Foshan Waterway, a typical municipal polluted river in PRD, China. The purpose of this study was to reveal the vertical distribution of AVS and toxicity of heavy metals in deep sediment in the heavily polluted area. Results of ΣSEM₅-AVS obtained in the current work indicated that sediment in the most surface layer (0~4cm) possessed potential biotoxicity, sediment in the sub-surface layer (4~10cm) had no potential biotoxicity, and the sediment biotoxicity fluctuated in deeper layers, and sediment below 45cm can be considered to exert no potential biotoxicity, where AVS was much larger than SEM₅. These revealed the biotoxicity of sediment demonstrated significant changes along vertical direction by displaying a layered distribution within 0~10cm, therefore to mix samples from different depths as a whole could not correctly assess the heavy metal biotoxicity of surface layer sediment.