This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to s...This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to study the dynamic effect of ozone on climate and vice versa. This is due to the fact that ozone and climate influence each other and the understanding of the dynamic effect of the interconnectivity is still an open research area. Monthly mean daily TOC and cloud cover data were obtained from the Earth Probe Total Ozone Mass Spectroscopy (EPTOMS) and the International Satellite Cloud Climatology Project (ISCCP)-D2 datasets respectively. Bivariate analysis and Mann Kendall trend tests were used in data analysis. MATLAB and ArcGIS software were employed in analyzing the data. Results reveal that TOC increased spatially from the coastal region to the north eastern region of the country. Seasonally, the highest value of TOC was observed at the peak of rainy season when cloud activity is very high, while the lowest value was recorded in dry season. These variations were attributed to rain producing mechanisms and atmospheric phenomena which influence the transport and distribution of ozone. Furthermore, the statistical analysis reveals significant relationship between TOC and low and middle cloud covers in contrast to high cloud cover. This relationship is consistent with previous studies using other atmospheric variables. This study has given scientific insight which is useful in understanding the coupling of the lower and upper atmosphere.展开更多
Heavy metals are elements, whose density is greater than water. They are generated from our environment. Rocks, sediments, plants, water and aerosol particles represent the carriers of heavy metals. An accumulated amo...Heavy metals are elements, whose density is greater than water. They are generated from our environment. Rocks, sediments, plants, water and aerosol particles represent the carriers of heavy metals. An accumulated amount of heavy metal in the body, either by inhalation, food or drinking water, can cause an adverse health effect to human. The Benue river passed through the town of makurdi, was high population of the inhabitant of Benue State dwells. The industrial and agricultural activities carried out in this region, increase the concentration of heavy metals. This may result to adverse health effect on the inhabitant of Makurdi. The objectives of this work were to determine the heavy metal concentration and its site contaminations along the bank of river Benue, Makurdi. An inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the heavy metals concentration. The metals concentrations (Iron, Copper, Manganese, Lead, Zinc, Chromium, Arsenic, and Cadmium) of the three stations were found. This ranges from 3.55 - 9454.0 mg/kg, 0.20 - 8928.0 mg/kg and 2.80 - 13,657 mg/kg for stations 1, 2 and 3. With Fe recorded as the highest concentration in the sediment, this value is compared with the World Health Organisation (WHO) and World Surface Rock Average (WSRA) standard. The assessment on contamination status of heavy metals in the riverbank, showed low degree of contamination in stations 1 and 2, and moderate degree in station 3. The degree of enrichment to heavy metals in all the stations is deficient to minimal. The evaluation of the results of pollution load index (PLI) from this present study indicated PLI 1 in stations 1 and 3. Hence stations 1 and 3 are polluted, while station 2 is not polluted with heavy metals.展开更多
Ionizing Radiation emitted from radionuclide has an adverse effect on human health. A continuing population exposure to naturally occurring radioactive materials (NORMS) found in our environment is one of the major sc...Ionizing Radiation emitted from radionuclide has an adverse effect on human health. A continuing population exposure to naturally occurring radioactive materials (NORMS) found in our environment is one of the major scientific subjects that attract public attention. The assessment of radionuclide content of shore sediments of river Benue-North Central Nigeria was carried out using gamma-ray spectrometry. The activity concentrations of U-238, Th-232 and K-40 were found to have an average concentration of 1.17, 3.31 and 405.95 Bq·kg-1 respectively. The values gotten from present study were compared with the world average values. World average values of U-238, Th-232 and K-40 are 50 Bq·kg-1, 50 Bq·kg-1 and 500 Bq·kg-1 respectively. The mean concentration of daughter radionuclides generated from U-238, Th-232 was 4.32, 10.37, 5.24, 3.86, 11.87, and 6.52 for Bi-212, Pb-212, Bi-214, Pb-214, Ra-226 and Ac-228, respectively. The mean of the absorbed dose, Annual effective dose equivalent, for radium equivalent activity, and external hazard index, were evaluated to be 19.45 nGy·h-1, 23.82 μSv·y-1, 37.16 Bq·kg-1, 0.10 mSv·y1, below the permissible limit of 57 nGy·h-1, 70 μSv·y-1, 370 Bq·kg-1 and 1 mSv·y-1 respectively. These shore sediments from river Benue are therefore, radiologically safe for construction and other domestic and industrial purposes.展开更多
文摘This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to study the dynamic effect of ozone on climate and vice versa. This is due to the fact that ozone and climate influence each other and the understanding of the dynamic effect of the interconnectivity is still an open research area. Monthly mean daily TOC and cloud cover data were obtained from the Earth Probe Total Ozone Mass Spectroscopy (EPTOMS) and the International Satellite Cloud Climatology Project (ISCCP)-D2 datasets respectively. Bivariate analysis and Mann Kendall trend tests were used in data analysis. MATLAB and ArcGIS software were employed in analyzing the data. Results reveal that TOC increased spatially from the coastal region to the north eastern region of the country. Seasonally, the highest value of TOC was observed at the peak of rainy season when cloud activity is very high, while the lowest value was recorded in dry season. These variations were attributed to rain producing mechanisms and atmospheric phenomena which influence the transport and distribution of ozone. Furthermore, the statistical analysis reveals significant relationship between TOC and low and middle cloud covers in contrast to high cloud cover. This relationship is consistent with previous studies using other atmospheric variables. This study has given scientific insight which is useful in understanding the coupling of the lower and upper atmosphere.
文摘Heavy metals are elements, whose density is greater than water. They are generated from our environment. Rocks, sediments, plants, water and aerosol particles represent the carriers of heavy metals. An accumulated amount of heavy metal in the body, either by inhalation, food or drinking water, can cause an adverse health effect to human. The Benue river passed through the town of makurdi, was high population of the inhabitant of Benue State dwells. The industrial and agricultural activities carried out in this region, increase the concentration of heavy metals. This may result to adverse health effect on the inhabitant of Makurdi. The objectives of this work were to determine the heavy metal concentration and its site contaminations along the bank of river Benue, Makurdi. An inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the heavy metals concentration. The metals concentrations (Iron, Copper, Manganese, Lead, Zinc, Chromium, Arsenic, and Cadmium) of the three stations were found. This ranges from 3.55 - 9454.0 mg/kg, 0.20 - 8928.0 mg/kg and 2.80 - 13,657 mg/kg for stations 1, 2 and 3. With Fe recorded as the highest concentration in the sediment, this value is compared with the World Health Organisation (WHO) and World Surface Rock Average (WSRA) standard. The assessment on contamination status of heavy metals in the riverbank, showed low degree of contamination in stations 1 and 2, and moderate degree in station 3. The degree of enrichment to heavy metals in all the stations is deficient to minimal. The evaluation of the results of pollution load index (PLI) from this present study indicated PLI 1 in stations 1 and 3. Hence stations 1 and 3 are polluted, while station 2 is not polluted with heavy metals.
文摘Ionizing Radiation emitted from radionuclide has an adverse effect on human health. A continuing population exposure to naturally occurring radioactive materials (NORMS) found in our environment is one of the major scientific subjects that attract public attention. The assessment of radionuclide content of shore sediments of river Benue-North Central Nigeria was carried out using gamma-ray spectrometry. The activity concentrations of U-238, Th-232 and K-40 were found to have an average concentration of 1.17, 3.31 and 405.95 Bq·kg-1 respectively. The values gotten from present study were compared with the world average values. World average values of U-238, Th-232 and K-40 are 50 Bq·kg-1, 50 Bq·kg-1 and 500 Bq·kg-1 respectively. The mean concentration of daughter radionuclides generated from U-238, Th-232 was 4.32, 10.37, 5.24, 3.86, 11.87, and 6.52 for Bi-212, Pb-212, Bi-214, Pb-214, Ra-226 and Ac-228, respectively. The mean of the absorbed dose, Annual effective dose equivalent, for radium equivalent activity, and external hazard index, were evaluated to be 19.45 nGy·h-1, 23.82 μSv·y-1, 37.16 Bq·kg-1, 0.10 mSv·y1, below the permissible limit of 57 nGy·h-1, 70 μSv·y-1, 370 Bq·kg-1 and 1 mSv·y-1 respectively. These shore sediments from river Benue are therefore, radiologically safe for construction and other domestic and industrial purposes.
