الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
he trace elements in cement: chormium, nickel and cobalt, particularly the hexavalent chromium, have been blamed for the occupational dermatitis reported among workers exposed or handling cement in general and wet cement in particular. Other trace elements present in cement (e.g. Cd, Cu, Zn, Mn,.. .etc) might also have probable effect(s) on health of workers handling cement or its raw material, or exposed to their dust; however, has not yet been investigated. The present study was conducted in an endeavour to investigate this subject through the qualitative determi nation of trace elements in the cement and the raw material used in its production, and in the total and respirable airborne dust to which workers involved in the different operations of cement production are exposed, and assess them quantitatively. Samples of ”parent materials” (viz: raw materi~ls, intermediate products and cement) were collected from the different production operations of the Alexandria cement production plant. Samples o£ airborne total dust were collected at different operatlons (viz: crushing of lime stone, grinding of raw materials, grinding of clinker and packing of cement) of the cement plant in Alexandria and the National and Torrah cement production plants in Cairo using a high volume el~c~ro2tati~Erecipitator. Respirable airborne dust samples were collected at the operations of the Alexandria plant using the same sampling instrument equipped with a cyclone pre-collector to exclude non respirable dust. Sample (four of each type of raw material or cement and/or of each operation) were analysed for chromium, nickel, cadmium, cobalt, copper, manganese and zinc using atomic absorption spectrophotometry, as well as for hexavalent chromium using a modified tested spectrophotometric method. Trace metals were present in the different samples in a mostly ascending order as follow$: cadmium, copper cobalt, nickel, chromium, zinc and the~_maa~ese. The trace metals concentration oftenly increased while progressing from one operation to another as additives rich with trace metals were added (e.g iron oxide or slag), or trace metals were worn off the internal surfaces of the grinding mill of the raw material (viz: zinc and manganese), the grinding mill of clinker (viz: chromium an~ manganese), and the rotary kiln (viz: all’the trace metals except for zinc which decreased in the produced clinker). . Most of the trace metals were the highest in the samples of total dust collected at the different operations of the Alexandria cement plant. Analysis of trace metals in respirable and total dust versus parent materia~s in Alexandria indicated that; mostly all trace metals (Cd, Co, Cu, Ni, Cl’, Zn, and to lesser extent Mn) were concentrated in total and/or respirable dust (the finer fraction) than in the parent material. which was attributed to the physical properties and chemical structure of the material. However, manganese was more concentrated in the clinker and cement than in dust evolved from these materials. which was attributed to the hardness of the iron slag, the main donnor of manganese Comparison of the concentrations of hexavalent chromium present in this study and reported in literature with the prevalence of cement eczema reported in the Egyptian and the foreign literature demonstrated clea’l’”’ly the relation of the prevalence of the cement eczema and the concentration of hexavalent chromium