Seasonal variation in bacterial heavy metal biosorption in water samples from Eziama river near soap and brewery industries and the environmental health implications     

I. Kanu  O. K. Achi  O. U. Ezeronye  E. C. Anyanwu 《International Journal of Environmental Science and Technology》2006,3(1):95-102

Seasonal variation in bacterial heavy metals biosorption from soap and brewery industrial effluent samples from Eziama River in Abia State were analyzed for Pb, Hg, Fe, Zn, As, and Mn, using atomic absorption spectrophotometry. Bioaccumulation of the metals by bacteria showed the following trend > Fe >Zn >As > Pb > Mn (Rainy Season) and Zn > Fe > Mn > As > Hg > Pb (Dry season). Statistical analysis using of variance (ANOVA) showed significant differences in concentrations of Pb, Hg, Fe, Zn, As, and Mn level between the sampling zones at Eziama River. Seasonal changes in heavy metal concentrations, showed increases in Pb, Fe, and As from 1.32 x 10⁵ mg/L in the rainy season to 1.42 x 10⁵ mg/L in the dry season. Fe increased from 40.35 x 10⁵ mg/L to 42.1 x 10⁵ mg/L, while As increased from 2.32 to 2.48 x 10⁵ mg/L with a net increases of+56 and + 69 x 10⁵ mg/L respectively. However, Hg, Zn, and Mn concentrations decreased in the rainy season from 40.54 x 10⁵ mg/L to 39.24 x 10⁵ mg/L, 1.65 to 0.62 x 10⁵ mg/L respectively.  相似文献   

Clay minerals in fluvial shaley sandstone of upper Triassic reservoir (TAGS)—Toual field SE Algeria: identification from wireline logs and core data     

Mazouz  El Hadi  Hamimed  Messaoud  Yahiaoui  Abdelouahab  Benzagouta  Mohamed Said  Khodja  Mohamed  Achi  Nada  Duplay  Joëlle 《Arabian Journal of Geosciences》2020,13(9):1-11

The creep property of rock under cyclic loading is very important in civil engineering. In order to establish a novel constitutive equation for rock under cyclic loading, a fractional-order viscoplastic body under cyclic loading was constructed based on fractional-order viscous element. A fractional-order visco-elastoplastic model (FVEPM) for rock was established by connecting constructed fractional-order viscoplastic body with Burgers model. The model was a Burgers model when the maximum value of cyclic loading was less than the critical strength of rock; otherwise, it was a FVEPM which can be used to reflect the transient, steady-state, and tertiary creep phases of rock. The cyclic loading was decomposed into a static load and a cyclic loading with a zero average stress. According to rheological mechanics theory, the rheology constitutive equation of rock under the static load can be derived. According to viscoelastic mechanics theory, the constitutive equation under cyclic loading with a zero average stress was established by introducing the variation parameters of energy storage and energy dissipation compliance caused by rock damage and fracture. Finally, a new dynamic constitutive equation of rock cyclic loading can be obtained by superimposing the constitutive equation under static load and cyclic loading with a zero average stress. Compared with existing test results of rock under cyclic loading, the proposed constitutive model can be used to describe the creep characteristics of rock under cyclic loading and reflect the presented fluctuation of strain curve of rock under cyclic loading.  相似文献