Spatial, Temporal and Depth Profiles of Trace Metals in an Urban Wetland System: A Case Study with Respect to the Deepor Beel, Ramsar Site 1207, India

The Deepor Beel is a permanent, freshwater wetland at the southwest corner of Guwahati (India) and it is a major stormwater storage basin for the city. Beel was designated as a Ramsar site (No. 1207) in 2002 and recognized as an important habitat for a large number of migratory aquatic birds. Orchids of commercial value are also found in the forests on the bank. The Deepor Beel is presently under stress due to excessive fishing activities, hunting of water fowl, input of contaminants from the agricultural fields and industries in the surroundings and infestation by water hyacinth. This study reports on monitoring of pH and 10 trace metals (As, Cd, Cr, Co, Cu, Ni, Mn, Pb, Hg, Zn) in the Deepor Beel water at 13 sites for three different depths consisting of surface layer, middle layer or euphotic zone, and bottom layer or euphotic zone x 1.5. The assessment was done bimonthly for a year.