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E. U. Onweremadu M.Sc. Ph.D. E. T. Eshett lecturer professor G. E. Osuji Head of department lecturer professor of soil conservation physics &environment 《International Journal of Environmental Science and Technology》2007,4(1):35-41
Studies on seasonal changes of heavy metal concentration in soils provide vital information for best management options at all times. The study investigated temporal variation in concentration of heavy metals in three towns having automobile service centres in Imo State. The study site is characterized by two major seasons in a year. Heavy metals were found in both arable and automobile soils, but more concentrations were recorded on the latter. Mean values of Cd, Cr, Ni, Hg and Pb were 6.2 mg/kg, 4.7 mg/kg 6.5 mg/kg, 0.02 mg/kg and 71.9 mg/kg respectively in the dry season while 2.9 mg/kg Cd, 2.2 mg/kg Cr, 1.9 mg/kg Ni, 0.01 mg/kg Hg and 51.9 mg/kg Pb were recorded during the rainy season of the experimental period. Higher values of heavy metal concentration were found in automobile soils as follows: 18.1 mg/kg Cd, 12.0mg/kgCr, 16.3 mg/kg Ni, 4.8 mg/kg Hg and312.8 mg/kg Pb in rainy season, and 15.1 mg/kg Cd, 8.1 mg/kg Cr, 11.9 mg/kg Ni 2.7 mg/kg Hg and 267.9 mg/kg Pb. However, Cd showed highest variability in arable soils during the dry season (CV=79%) while Hg varied widely in automobile soils in the rainy season (CV=54%). 相似文献
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Loess: The Yellow Earth 总被引：1，自引：0，他引：1
Secretary of the INQUA Loess Commission Ian Smalley & senior lecturer Chris Rogers 《Geology Today》1996,12(5):186-193
A wind-deposited silt forming large deposits in China and middle America, loess is the basis of much grade-one agricultural land. 相似文献
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WANG JinlingCHENG YongqiTAO BenzaoWANG Jinling lecturer school of Geo-science Surveying Engineering WTUSM Wuhan China 《地球空间信息科学学报》1998,(1)
Up to now,outlier detection and reliability theory are generallybased on the regular Gauss-Markov models,in which the covariance matrix of ob-servations is positively definite.For the adjustment models with singular covari-ance matrix,the statistics for outlier detection are derived by the authors.Thecorresponding reliability theory is developed.And the application of the theory isdemonstrated with a practical example. 相似文献
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Fossil charcoal: a plant-fossil record preserved by fire 总被引：2，自引：0，他引：2
Small pieces of black organic material are common in many post-Devonian sequences, both sedimentary and volcanic. While many of these are coalified plant fragments, others are fossil charcoal, also known as fusain. Charcoalification preserves exquisite detail of the plant ultra-structure and is best viewed by scanning electron microscopy. 相似文献
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