Health hazards among workers in power stations comparative study between natural gas and mazout stations

This study was done on 65 workers working in power station I [Shoubra El-Kheima] where they are exposed to natural gas and mazout, 74 workers in power station II [El-Gharb] where there is mazout exposure only and 74 individuals acting as controls. All these individuals were admitted to a questionnaire, examined clinically and they were investigated to assess their respiratory, liver and kidney function tests. This is in addition to a complete blood picture. Air pollution inside these stations was assessed. The study aimed at determining the pollutants inside and outside the stations and to investigate the health hazards of the workers exposed to these pollutants. It aimed also to see if it is important and urgent to replace the mazout by natural gas as a fuel in these power stations. The results showed that by products of mazout have bad effect on the environment. When mazout is used alone as a fuel, it has an adverse effect on the respiratory system and the liver. There is a need for a prospective study to assess the causal relationship between mazout by-products and health hazards before taking the decision of replacing mazout by natural gas

Effect of irradiation on microbial indicators during sewage treatment

A study was carried out to assess the changes in the population densities of certain microbial groups of hygienic significance throughout the successive steps of treatment in Virginia Key Wastewater Plant in Miami, Florida. Samples were taken from raw sewage, oxygenated tanks, settling tanks and chlorinated effluent. Total count, total coliform, Streptococcus faecalis, Aeromonas hydrophila and coliphage increased or remained unchanged after oxygenation but they sharply decreased in settling and chlorination tanks were more than 99% reduction in counts initially present was observed. A. hydrophila and coliphage were still detected in the final effluent. With respect to the last stages of treatment till the production of dewatered sludge, all tested groups of microorganisms attained their highest values in the effluent of concentration tanks. They decreased throughout the steps of treatment till the dewatered sludge to attain 106-105 cfu/g for total counts and total coliform as well as 104 cfu/g for A. hydrophila and S. faecalis and 103 pfu/g for coliphage. An experiment was conducted to study the efficiency of gamma radiation in reducing the microbial load in the chlorinated effluent and dewatered sludge. In the chlorinated effluent, total counts, S. faecalis and coliphage were eliminated with 2 kGy while 1 kGy was sufficient to eradicate total coliform and A. Hydrophila. Regarding the dewatered sludge, a dose of 6 kGy was quite sufficient to decrease total counts from 6x105 to few cells/g. Whereas, total coliform, S. Faecalis and A. hydrophila could not be detected after irradiation with 2,4 and 1 kGy respectively. Coliphage was eliminated after irradiation with 6 kGy. Another experiment was carried out to compare the effect of gamma radiation with that of electron beam on microbial groups in chlorinated effluent. At any given dose of radiation, gamma rays proved to be of more lethal than electron beam for all types of organisms

Microbiological quality of local dehydrated soups with special reference to Bacillus cereus

A total of 105 samples of precooked dehydrated soups representing the different types produced in Egypt were examined. Moisture content ranged from 1.5 to 6% and pH values were between 6.9 and 7.7. Mean values of total bacterial counts were generally less than 105 CFU/g except for brand "F" which contained about 103 CFU/g. Wide variation in the percentage of sporeformers in total count was observed. Mean values of spore counts ranged from 103 to 104 CFU/g. Bacillus cereus was found in variable densities; mean values hardly exceeding 104/g, it was not detected in some samples. Generally, B. Cereus represented 20-70% of the total spore counts. Yeast colony mean counts around 102 CFU/g. Enterobacteriaceae, molds coliforms, Staphylococcus aureus, Streptococcus faecalis and salmonellae could not be detected in all samples. D10 value of B. cereus was 2.85 KGy, while the D10 values at 85, 90, 95 and 100C were found to be 15.0, 9.5, 8.5 and 2.5 min, respectively. Preirradiation treatment of B. cereus spores had a synergistic effect with heat treatment