Chemistry and Ecology Vol. 24, No. 4, August 2008, 297–303 Analysis of silver in the water column of the Pra and the Eture estuaries in Ghana D.K. Essumang a * and B.K. Nortsu b a Department of Chemistry; b Department of Laboratory Technology, University of Cape Coast, Cape Coast, Ghana (Received 23 January 2008; final version received 6 June 2008 ) Silver is a rare but naturally occurring metal, often found deposited as mineral ore in association with other elements like gold, manganese and aluminium. Emission from smelting and gold mining operations as well as indiscriminate disposal of waste from photographic laboratories and other chemical laboratories are some of the anthropogenic sources of silver in the environment. This work analysed the concentration of total recoverable silver in the water column of the Eture and the Pra estuaries in Ghana. The result indicated high concentrations in the two estuaries, higher than the values that should be tolerated in the estuarine environment. The high levels in the Pra estuary could be attributed to the numerous mining activities upstream and this was the same for the Eture estuary which also runs through Cape Coast and the University of Cape Coast. The higher levels of silver reported in this study area suggest that much work has to be done to monitor and improve the quality of these ecosystems in the Ghanaian environment. Keywords: silver; Pra estuary; Eture estuary; gold mining 1. Introduction Silver is a rare but naturally occurring metal, often found deposited as a mineral ore in association with other elements like gold. Emission from mining and smelting operations, manufacture and the disposal of certain photographic and electrical supplies, coal combustion and cloud seeding are some of the anthropogenic sources of silver in the biosphere [1]. The global biogeochemical movements of silver are characterised by releases to the atmosphere, water, and land by natural and anthropogenic sources, long-range transport of fine particles in the atmosphere, wet and dry deposition, and sorption to soils and sediments [1]. Silver in the aquatic environment has received attention in recent years because it is highly toxic to aquatic organisms even at trace levels, and widely distributed in the vicinity of industrialised areas [2–4]. The most recent measurements of silver in rivers, lakes and estuaries using clean techniques showed values about 0.01 μg/l for pristine and unpolluted areas and 0.01–0.1 μg/l in urban and industrialised areas [1]. In the water column, silver is readily adsorbed onto particles due to its high particle affinity (typical partition coefficient, K d of 10 4.5 to 10 6 ); thus, sediment constitutes the main *Corresponding author. Email: kofiessumang@yahoo.com ISSN 0275-7540 print/ISSN 1029-0370 online © 2008 Taylor & Francis DOI: 10.1080/02757540802253944 http://www.informaworld.com