In this article, the latest development on the study of acid-volatile sulfide in aquatic sediment is reviewed. Acid-volatile sulfide (AVS) is operationally defined as sulfide in sediment which is soluble in cold acid, and was reported as the most active part of the total sulfur in aquatic sediments and a key partitioning phase controlling the activities of divalent cationic heavy metals in sediment. It has been reported that the measurement procedures of AVS concentration are very important for AVS study, t...