Heavy metals originating from the use of fertilizers and pesticides are toxic pollutants that limit the beneficial use of water for agricultural, domestic and industrial applications. Three vegetable production basins in the Western Highlands of Cameroon (Bafou, Foumbot and Santa) were surveyed in March 2013, to determine the concentration of heavy metals (Pb, Cd, Cu, Fe, Mn) in surface water. A total of 21 surface water samples were collected and transported to the laboratory where heavy metals were analyzed with a flame Atomic Absorption Spectrometer (AAS). Analysis of variance was carried out to show differences in the heavy metal concentrations from the different basins using SPSS. Results showed that surface water was slightly acidic pH (6.2-7.0). Cd, Pb, Fe, Cu and Mn concentrations ranged between 0.002-0.042, 0.016-1.555, 0.001-0.200, 0.026-1.506 and 0.001-0.519 mg/L respectively. Highest mean concentrations of Cd (0.019 mg/L) and Cu (0.122 mg/L) were observed in Foumbot, Fe (0.420 mg/L) and Mn (0.054 mg/L) in Bafou and Pb (0.322) in Santa. Results showed no significant differences (p>0.05) in mean concentrations of Pb, Cu, Fe and Mn in these basins. Concentrations of heavy metals in water were significantly higher (p<0.05) than those of their control. Generally, results revealed that some heavy metals (Pb, Fe and Mn) were higher than WHO permissible limits while Cd was detected above both the World Health Organization and Food and Agriculture Organization of the United Nations safe limits which can pose health risks to the consumers. Consequently, regular monitoring is needed to alert farmers when heavy metal concentration in water is above safe limits.
Vertical Electrical Sounding (VES) was applied in investigating the subsurface layers along Adibawa-Zarama pipeline route in the Niger Delta, Nigeria in an attempt to determine the depth of aquifer. A total of thirty (30) VES sets were executed using Schlumberger array of a maximum half current electrode spacing of 50m and interval distance of 250 m along the 6.75 km Adibawa-Zarama route. The fundamental parameters of resistivity, conductance, anisotropy and depths were computed using Resist software. Transverse resistivity is generally higher than longitudinal resistivity, and it ranges from 70.49 Ω m to 936.30 Ω m while those of longitudinal ranges from 31.37â Ω m to 585.81Ω m. Anisotropy value ranges from 1.01 to 1.75 which is an indication that the layers are laterally inhomogeneous. The 1st layer has a resistivity range of 40.00 Ω m - 453.00 Ω m the 2nd layer resistivity range is 17.00 Ωm - 320 Ω m, 3rd layer has resistivity range of 130.00 has resistivity range of m - 1400.00 Ω m, 4th layer has resistivity ranges from 23.00 Ω m - 1450.00 Ω m, the 5th layer has resistivity range of 220.00 Ω m - 4950.00Ω m, while the 6th layer has resistivity range of 600.00 Ω m - 3997.00 Ω m. The minimum and maximum thicknesses for the respective first five layers in sequence are: 1.45 m and 3.0 m, 0.75 m and 4.10 m, 1.42 m and 15.04 m, 3.10 m and 23.20 m, and 7.00 m and 18.90 m. The saturated layers occur mostly in third, fourth and fifth layers are at depths 12.87 m and 26.02 m and 38.97 m respectively. Clay was located at a depth from 0m to 5m, while beyond these depths the formation is clayey sand to sandy clay, fine sand, clayey sand and sand of various grades. Tying results of the geoelectric survey to various lithologies reveals that resistivity is affected by lithology and fluid content of the rock. The aquifer is thick and is located between 12.87 m and 38.97 m.
A geoelectrical investigation for potable groundwater potentials in Dorowa and its environs, Plateau State, North Central Nigeria has been carried out. The area is part of Jos-Bukuru Younger Granite Complex and is underlain by seven main rock types namely: Vom Microgranite (Vm), Rayfield Gona Biotite Granite (RGB), Ngell Biotite Granite (NGB), Vom Hornblende Biotite Granite (VHB), Shen Hornblende – Fayalite Granite (SHF), Porphyritic Biotite Granite (PBG) and Jos Biotite Granite (JBG). Interpretation of field structures and GIS data reveal lineaments trending NW-SE and NE-SW. Vertical electrical soundings conducted within Ngell biotite granite reveals that the area is underlain by three geoelectric layers. The top layer is mainly made up of laterite at depth between 0 - 5 m with resistivity values ranging from 79 – 202 â„¦m, the second layer is made up of weathered granite at depth between 3 – 16 m with resistivity between 46 - 396 â„¦m and the third layer is made up of slightly weathered to fresh granite at depths greater than 4 m with resistivity greater than 113 â„¦m. The zones of medium groundwater potential vary from 15 -16 m. Weathering depth in areas of fair water potentials varies from 13m – 14m with the best water potentials on VES 10 and VES 6. Zones of low groundwater potentials cover most part of the study area at depth less than 12m.
A better understanding of the future climate pattern developments in the Arctic may only follow a better reconstruction of the past patterns of natural oscillations and the determination of the forcing and the resulting oscillations occurred in the climate parameters over different time scales. The proposed information for the past demonstrates the Walsh & Chapman reconstruction  claiming a flat sea ice 1870 to 1950 is too simple. The Arctic sea ice experienced a drastic reduction that was phased with warming temperatures 1923 to 1940. This reduction was followed by a sharp cooling and sea ice recovery. This permits us to also conclude that very likely the Arctic sea ice extent also has a quasi-60 years’ oscillation. The recognition of a quasi-60 year’s oscillation in the sea ice extent of the Arctic similar to the oscillation of the temperatures and the other climate indices may permit us to separate the natural from the anthropogenic forcing of the Arctic sea ice. The heliosphere and the Earth’s magnetosphere may have much stronger influence on the climate patterns on Earth including the Arctic sea ices than has been thought.
Vinícius Verna Magalhães Ferreira, Amanda Lafetá Oliveira, Raquel Luiza Mageste Fonseca, Natália Manuele Gomes de Oliveira, Rodrigo Oscar de Albuquerque, Carlos Alberto Carvalho Filho, Lúcia Maria Alencar Labossiere Auler
Aims: The goal of this study is to perform the characterization of bottom and in suspension sediments at Serra Azul stream. Chemical, mineralogical and grain size aspects were evaluated, as also the legal issues pertinent to this matter. Study Design: Hydrosedimentological studies at Juatuba basin. Place and Duration of Study: Juatuba basin – southeast part of Brazil, between December 2013 and October 2014. Methodology: The bottom and in suspension sediments of Serra Azul stream were characterized through different techniques: x-ray diffraction, x-ray fluorescence and grain size analysis (using sieves and laser techniques). The environmental legislation was checked in order to see the values of the allowed concentrations of some heavy metals in the waters. Also, the data of a small hydrometric network were treated in order to obtain the natural flows of the water courses. Results: Two elements found in the sediments in suspension were not found in bottom sediments: Chlorine and Bromine. Gallium, Lead, Barium and Nickel were not found in the bottom sediments samples in 2013, only in 2014. The concentration values of Chrome, Potassium, Sodium and Silicon became smaller in 2014, however for the other elements that were found, these values became bigger. The bottom sediments collected in the study area present values higher than the threshold above which a probable adverse effect on the biota is expected for Chrome and Nickel, in order of importance. When the global values of the dissolved constituents in surface waters were compared to the ones found at Juatuba basin, it was possible to verify that only for Iron and Aluminum the 2014 found values were bigger than the average elemental composition, according to a variety of sources and authors. Conclusion: The transport of sediments in the studied area showed that some heavy metals are being transported towards the Serra Azul reservoir in concentrations higher than the allowed ones. Due to a long dry season in the study area, this transport is currently minimized, however the next rain station can generate a serious scenario. It is necessary to implement a permanent program in order to collect and analyze these sediments, inclusive in other parts of the basin. It is also necessary to solve the question concerning to the absence of a legislation for several other chemical elements found in the sediments.