ADSORPTION OF MERCURY-COMPOUNDS BY TROPICAL SOILS .1. ADSORPTION IN SOIL PROFILES IN RELATION TO THEIR PHYSICAL, CHEMICAL, AND MINERALOGICAL PROPERTIES

Mercury adsorption of HgCl//2 and 2-methoxyethylmercury chloride (Aretan) (100 mg HG L** minus **1) was measured for three soil profiles from Morogoro, Arusha, and Dar es Salaam in Tanzania. The adsorption was investigated for the physical, chemical, and mineralogical properties of the soils. All soil samples showed greater capacity for adsorption of Aretan than for HgCl//2. In the Morogoro profile Hg adsorption decreased with depth but in the other two soils, the minimum adsorption occurred in the third horizon and increased both upwards and downwards. In the Morogoro profile, Aretan adsorption correlated well with pH. Adsorption of both Aretan and HgCl//2 correlated well with the distribution of organic C and with the cation exchange capacity of the soils. In the Arusha and Dar es Salaam profiles Hg adsorption was not significantly correlated with any of the soil properties tested.