Dehalogenation of polychlorinated biphenyls and polybrominated diphenyl ethers using a hybrid bioinorganic catalyst

The environmentally prevalent polybrominated diphenyl ether (PBDE) #47 and polychlorinated biphenyls (PCBs) #28 and #118 were challenged for 24 hours with a novel biomass-supported Pd catalyst (BioPd0). Analysis of the products via GC/MS revealed the BioPd0 to cause the challenged compounds to undergo stepwise dehalogenation with preferential loss of the least sterically hindered halogen atom. A mass balance for PCB #28 showed that it is degraded to three dichlorobiphenyls (33.9 %), two monochlorobiphenyls (12 %), and biphenyl (30.7 %). The remaining mass was starting material. In contrast, while PCB #118 underwent degradation to yield five tetra- and five trichlorinated biphenyls; no less chlorinated products or biphenyl were detected, and the total mass of degraded products was 0.3 %. Although the BioPd0 material was developed for treatment of PCBs, a mass balance for PBDE #47 showed that the biocatalyst could prove a useful method for treatment of PBDEs. Specifically, 10 % of PBDE # 47 was converted to identifiable lower brominated congeners, predominantly the tribrominated BDE 17, and the dibrominated BDE 4, 75 % remained intact, while 15 % of the starting mass was unaccounted for

Studying the Amount of Noise Exposure and Measuring the Hearing Loss in Workers of Door and Window Construction Factory

Material and method: by using a dosimeter we tried to study the amount of noise exposure each worker is exposed to; the microphone was connected to the collar of the shirts and the dosimeter to the belt. The audiometric evaluations were performed before starting work in the factory. Results: the years of experience in the factory has a significant correlation with amount of hearing loss in the workers of the noisy environments (based on the findings of the dosimetric measurements) Conclusion: the findings of the current study demonstrated that workers of the door and window construction factory were exposed to high level of noises and their hearing thresholds were largely affected by the noise pollution. This is in accordance with results of the similar studies. This impact was mostly revealed in the forgers