ABSTRACT
To assess the environmental radioactivity levels and hence to determine the population exposure in Kutubdia Island, Bangladesh the sediment samples were analyzed by using gamma ray spectrometry. In those sediment samples the average activity concentration of natural radionuclides [238]U, [232]Th and [40]K were found 15.39+/-1.67, 38.35+/-0.76 and 475.51+/-21.15 Bq/kg respectively. The activity concentration of [238]U and [232]Th were less than the world average. But the activity concentration of 40K was higher than the world average values. These results were used to calculate the radiological hazard parameters like radium equivalent activities [Ra[eq]], representative level index [I[gammar]]. Due to natural radionuclides in sediment, the effective annual outdoor dose in the study area was 0.07 mSv; which is within the accepted range of 0.07 mSv. The average value of radium equivalent activities [Ra[eq]] and representative level index [Igr] were found to be 128.03+/-12.08 Bq/Kg and 0.96+/-0.09 Bq/Kg which were greater than the world average. The anthropogenic radionuclide [137]Cs was also found in few samples. The average activity concentration of [137]Cs was 1.64+/-0.20 Bq/kg which is lower than the world average. The obtained experimental data of this research work would be useful to assess the population exposure from radionuclides in sediment as well as base line data of natural radioactivity in this island
ABSTRACT
Ethambutol is considered to have a relative lack of toxicity. In Bangladesh, out of a total of 350 patients receiving ethambutol [25 mg to 35 mg/kg daily] for tuberculosis, 20 [5.71%] developed neuroretinal toxicity. Ten [50%] of these patients had peripheral, four [20%] central, and six [30%] mixed visual field defects. Thirteen [65%] patients recovered, with or without additional treatment, after ethambutol was stopped, but seven [35%] had irreversible damage. In several of the patients who recovered, the visual improvement began only when hydroxycobalamin was administered following the discontinuation of ethambutol. One woman mistakenly received cyanocobalamin instead of hydroxycobalamin, leading to optic atrophy and an irreversible visual loss in her. We would like to warn against the use of cyanocobalamin in patients on ethambutol