Synek 0., S. Zima, M. Sucmanova, E. Sucman: Determination of Lead, Mercury and Arsenic in Feeding Phosphates. Acta vet. Bmo, 47, 1978: 153-158. Elaborated was the method of determination of lead, mercury and arsenic in feeding phosphates by means of atomic absorption spectrophotometry. Five different types of foreign and Czechoslovak phosphates commonly used for the preparation of feed mixtures were analyzed. The content of lead, mercury and arsenic ranged from 0.72 to 6.89 mg kg-I, 0.09 to 0.37 mg kg-l and from 0.75 to 69.77 mg kg-I, respectively. With regard to the content of all the three elements studies it was found that the relatively purest was dinatriumphosphate (Fosfa, n. p.), while the highest amount of admixtures was found in monocalciumphosphate (Reymeshoim) and dicalciumphosphate (CKF).
Microelements, atomic absorption spectrophotometry, feed mixtures.The ever increasing industrialization and intensification of agricultural large-scale production necessitates investigations of new aspects in the nutrition of farm animals, aspects that had not been important before. One of the problems discussed has recently become the content of some microelements in feeds and feed mixtures; the intense development of instrumentation techniques over the past years has enabled these investigations to be carried out. The most important of these microelements are lead, cadmium, mercury and arsenic, indicated as "toxical civilization elements". The importance of uptake of these elements by farm animals should be judged from two aspects. i. e. from the point of view of the health condition of animals (possible intoxication, etc.), and because feed is the first link of the food chain which ends in man. Whereas the final links of this chain (raw materials for the preparation of foodstuffs, finished products, etc.) have already been studied, are being discussed, or there already exist standards for the admissible contents, in the field of feeds not many studies of this kind exist. These studies are aimed namely at lead of which namely the increased content in conventional feeds is closely associated with civilization. The intoxication of farm animals with lead in the industrial regions and in the vicinity of main roads with heavy traffic is becoming an ever increasing problem (Matyas 1975).The most important mineral components of feed mixtures include various types of phosphates, representing 1-10 % of the total composition of feed mixtures. With regard to the initial raw materials and the industrial character of the production of these substances the present study deals with the determination of lead, mercury and arsenic in the most frequently used types of feeding phosphates of both foreign and Czechoslovak origin.
Materials and MethodsSamples of dicalcium phosphate (DCP) and monocaIciumphosphate (MCP) imported to Czechoslovakia in 1975Czechoslovakia in -1977 as mineral feed admixtures were analyzed as for the content of lead, mercury and arsenic. The other phosphates studied (dinatriumphosphate, pyrophosphat...
