Determinatioh Of' Total Arsenic in Streams and Sediments from Obuasi Gold Mines

Abstract

In this work streams and sediments of Obuasi, a major gold mining town in Ghana were analysed. In addition to the total arsenic the parameters determined included the levels of Pe, Al, Nn and Au# and nutrients. Leaching of arsenic from the sediment was also carried out to ascertain the rate at which as will be removed from the sediment to acceptable levels. Results indicate that in spite of the newly installed Arsenic Recovery Plant <ARP> which is able to remove about 90X of the arsenic dusts, the streams in the area remain heavily polluted with arsenic. In the water Total Arsenic values range between 0.13 - 20.OOppm. The sediments are also polluted to a depth of at least 30cm with values ranging from 15.38 - 50.OOppm. Contrary to expectations, the gold concentration in both the water and sediment are too low and may not be suitable for exploration. The leaching results show that very little amount of arsenic was leached from the sediments. Even after 20 weeks of continuous leaching less than 15! of As had been leached. This was attributed to the ability of arsenic to form spai— ingly soluble compounds with Fe, Al, Mn etc in the sediment environment.