Enkele aspekte rakende die bio-beskikbaarheid van chemiese verbindings afkomstig van Suid-Afrikaanse vliegas

Abstract

The bioavailability of chemical compounds found on South African coal fly ash particles collected from Kendal, Lethabo and Matimba power stations was examined. Physiological sodium chloride solution, hydrochloric acid and simulated surfactant were used as leaching solutions to simulate human/fly ash interaction. The toxic potential of the leachates was evaluated by means of a lethality test (Daphnia test). The Salmonella Ames Spot test was used to detect mutagenic activity. The presence of metal compounds in the leachates was established by means of the Metal indicator test. Of the leaching solutions used hydrochloric acid was found to be the most efficient followed by physiological sodium chloride solution and simulated surfactant. Fly ash collected from Kendal power station had the highest toxic potential whilst the toxic potential of fly ash from Lethabo and Matimba power stations was more or less on a par. None of the leachates showed any mutagenic potential. The highest concentrations of metal compounds were recorded in respect of the Kendal leachates. The in vitro tests conducted in this study disclose certain tendencies. The results, however, cannot be directly applied to human beings. As the chemical compounds on fly ash can leach when coming into contact with body fluids and thus spread throughout the body, a long term biological monitoring programme based on the present study, can be embarked upon to establish whether the exposure to fly ash of personnel working in coal power stations, poses a health hazard to them.