Trace metal speciation trends in Mazowe dam, Zimbabwe, a typical sub-tropical dam ecosystem impacted by gold mining and agriculture.

The present study aimed to assess trace metal speciation trends in the water and sediments of Mazowe Dam, a typical sub-tropical dam ecosystem impacted by gold mining and agriculture in Zimbabwe. The elements studied include Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn. Elemental speciation in the water column was determined using Visual MINTEQ version 3.

Persistence and fate of chlortetracycline in the aquatic environment under sub-tropical conditions: generation and dissipation of metabolites.

The persistence of chlortetracycline in the aquatic environment, including the generation and dissipation of its metabolites, were investigated over a period of 90 days using microcosm experiments, with a view to establishing the metabolites generated and their persistence under conditions closely resembling the actual aquatic environment in terms of chemical and microbial composition. The concentrations of chlortetracycline and its metabolites were monitored in the water phase as well as the sediment phase. Data are presented showing that the degradation of chlortetracycline in each phase conforms to a triphasic linear rate law, confirming the existence of three speciation forms in each phase, attributed to one free dissolved form, and two colloidal particle adsorbed forms.