This is a preliminary report on total mercury (T Hg) in core sediments (<63 μm particle size) of Sunderban mangrove wetland, northeastern part of the Bay of Bengal, India. Cold vapor atomic absorption spectrometry (CVAAS) was used for T Hg determination. The concentration varies from 9.8 to 535.1 ppb (ngg -1). Results revealed variations over premonsoon and postmonsoon month at different core depth, as well as in studied three sampling stations, located at the site of three rivers: Hugli River (S 1), Matla River (S 2) and Bidyadhari River (S 3). Elevated concentration of T Hg in subsurface layer (4-8 cm) of the core at S 2 is attributed to remobilization of mercury from deeper sediment (32-36 cm). Positive correlation is present between total Hg and clay content. Based on index of geoaccumulation (I geo) and Effects-Range Low (ER-L) value (150 ppb) it is considered that the sediments are till now unpolluted. As a consequence, there is less chance of ecotoxicological risk to organisms living in studied sediments. Two statistical methods were applied to determine T Hg anomalies. Box plot method showed one extreme and three outliers in S 1 at postmonsoon season. Two extremes were found at S 2 at 4-8 and at 32-36 cm in premonsoon period. In S 3 there was no anomaly by box plot method. MAD method was more sensitive than box plot method and T Hg anomaly was detected at 12-16 cm in S 3 during postmonsoon season. The data reported are useful baselines for T Hg in Sunderban mangrove wetland, India and would be of help in future sediment quality studies. © 2008 Springer Science+Business Media, LLC.