Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related in...Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(Ⅵ) (2.7-12.6 mg/L), Cu(Ⅱ) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(Ⅵ), Cu(Ⅱ) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(Ⅵ) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(Ⅱ) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose.展开更多
The analysis of naturally occurring radionuclides （226Ra, 232 Th and 40 K） and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. （Pakistan）, usin...The analysis of naturally occurring radionuclides （226Ra, 232 Th and 40 K） and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. （Pakistan）, using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium （HPGe） detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq.kg-1 for 22TRa, 21.73 to 75.28Bq.kg- 1 for 232Th, 7.06 to 14.9Bq.kg 1 for 1arcs and 298.46 to 570.77Bq.kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq.kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report （370 Bq.kg-1）. Man-made radionuclide 13r Cs is also present in detectable amount in all sell samples. Presence of 13r Us indicates that the samples in this renlote area also recelvo some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.展开更多
文摘Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(Ⅵ) (2.7-12.6 mg/L), Cu(Ⅱ) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(Ⅵ), Cu(Ⅱ) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(Ⅵ) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(Ⅱ) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose.
文摘The analysis of naturally occurring radionuclides （226Ra, 232 Th and 40 K） and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. （Pakistan）, using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium （HPGe） detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq.kg-1 for 22TRa, 21.73 to 75.28Bq.kg- 1 for 232Th, 7.06 to 14.9Bq.kg 1 for 1arcs and 298.46 to 570.77Bq.kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq.kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report （370 Bq.kg-1）. Man-made radionuclide 13r Cs is also present in detectable amount in all sell samples. Presence of 13r Us indicates that the samples in this renlote area also recelvo some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.
