ABSTRACT
Revised text based on EIFAC Technical Paper 43, 1983 and additional material, revised by
G. HOWELLS Zoology Department, University of Cambridge, Downing Street,
Cambridge, CB2 3EJ
1. INTRODUCTION
1.1. Sources and Occurrence of Chromium
Chromium is a metal of widespread natural occurrence, although not as the pure metal, but generally as trivalent or hexavalent chromium. It is found in spinel-type minerals (iron and magnesium chromo-aluminates) and as chromite (FeO.Cr203) which is the most important mineral for refining. Chromium is mined in the Philippines, South Africa, Turkey, Russia and Zimbabwe, and is widely used in industry. Several general reviews list the concentrations in the ores (Cheremisinoff and Habib, 1972; NRCC, 1976) and tonnages produced (NRCC, 1976; Van der Velde,1978). A number of papers refer to specific industrial uses, for example tanning (Ryder, 1978; Smillie et al., 1981; Wickliff et al., 1982; Ziglio and Del Corno, 1979), metal-plating (Pfeiffer et al., 1980), as mordants in textiles (US EPA, 1980) and as an anti-corrosion agent in cooling water systems (Cranston and Murray, 1980; Landy, 1971; Young and Jan, 1977). The presence of chromium (Imhoff et al., 1980; Jan et al., 1977; Schafer, 1976) and details of the methods and problems of treating waste waters containing chromium have been reported (Ryder, 1978; Wickliff et al., 1982). Chromium in fly ash (Egget and Thorpe, 1978) and deposited from air after a major bush fire (Young and Jan, 1977) have also received attention.
