Abstract

Cowhides ‘ponmo’ prepared by various and unknown processing methods were purchased from several markets in Lagos and environs and the contents of lead, cadmium, chromium, zinc, mercury and arsenic were determined before and after boiling. Significantly high levels of these metals except cadmium and zinc were found in all the samples obtained after boiling. The highest levels of Pb (1.54 mg.kg^-1), Cr (0.79 mg.kg^-1) and As (2.85 mg.kg^-1) were found in singed hides processed with flame fuelled by plastics mixed with refuse while Hg (6.74 mg.kg^-1) content was highest in singed hides processed with burning tyres. However, cadmium (0.10 - 0.38 mg.kg^-1) was detected in three samples of hides randomly obtained from the open market and hence of unknown processing methods. The lowest levels of the metals were usually found in hides processed through the traditional method of boiling in water followed by shaving. A sample of the ‘black oil’ used as fuel in one of the processing methods was found to have lead content as high as 31.4 mg.dm^-3. Some samples of the ash scraped from the singed cowhides were found to have high levels of Pb, Cd, Cr, Zn, Hg and As. The ash is usually carelessly handled and often disposed into streams by food processors thus causing extensive water pollution. Several of the samples were found to be toxic and suggestions are made about how to obtain cowhide samples that are fit for consumption and eliminate pollution and health hazards associated with processing cowhides.

Key words: Heavy metal concentrations, meat products, cowhides.