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The determination of trace and toxic elements in biological samples (blood, urine and scalp hair samples) of human beings is an important clinical test. The aim of our present study was to determine the concentration of arsenic (As), copper (Cu), cobalt (Co) and manganese (Mn), in biological samples of male production workers (PW) and quality control workers (QW) of steel mill, with aged 25-55 years, to assess the possible influence of environmental exposure. For comparison purpose, the same biological samples of unexposed healthy males of same age group were collected as control subjects. The determination of all elements in biological samples was carried out by electrothermal atomic absorption spectrometry, prior to microwave assisted acid digestion. The accuracy of the As, Cu, Co and Mn measurements was tested by simultaneously analyzing certified reference materials (CRMs) and for comparative purposes conventional wet acid digestion method was used on the same CRMs. No significant differences were observed between the analytical results and the certified values, using both methods (paired t-test at P > 0.05). The results indicate that concentrations of As, Cu, Co and Mn in all three biological samples of the exposed workers (QW and PW) were significantly higher than those of the controls. The possible correlation of these elements with the etiology of different physiological disorders is discussed. The results were also demonstrated the need of attention for improvements in workplace, ventilation and industrial hygiene practices.

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AN important factor affecting the keeping quality of oat-based food products is the presence of residual lipase, but occasionally the stabilisation process carried out by oat millers prior to groats being ground, flaked or rolled may not result in fully de-activating the enzyme present. The more usual method for detecting residual lipase activity is based on the increase in acidity of fat after incubation but, because of the time required to complete the test, a more rapid qualitative test was considered desirable from the quality control aspect.Until recently, the method used in this laboratory for routine examination of deliveries of oat flour and rolled oats was a colorimetric test for tyrosinase (private communication from Quaker Oats Ltd., Southall, Middlesex), which is also present in oats and which acts on tyrosine and catechol derivatives to form pink dihydroxyindole and finally melanin. This test required only 30 minutes to complete and was adequate provided no colour was produced, but a positive result for tyrosinase made it necessary to carry out the incubation test and, as in our experience about 50 per cent. of the samples received in this laboratory giving a positive tyrosinase reaction were found subsequently to be free from lipase activity, a more specific test was required.Such a test that will give a quick indication of the presence of residual lipolytic enzymes in oat products has been developed. REAGENTS-(Research and Development, Tea Division, J . Lyons 6. Company Limited, Greenford, Middlesex) EXPERIMENTAL Calcium acetate, analytical-reagent grade. Phenol red indicator, 0-02 9er cent. w / v . Sodium carbonate, 5 $er cent. wlv, analytical-reagent grade. Formaldehyde, 40 per cent. wlv. PROCEDURE-Transfer about 2 g of the sample to an 8 x l-inch glass-stoppered tube, add 20 ml of