Besides electrochemical corrosion protection, laser shock peening provides extended fatigue life and mechanical properties for metals, as reported in the literature. However, most of the studies were performed under static conditions. The effectiveness of this method under flow conditions and prolonged immersion duration is addressed in this study. Copper discs were peened with Nd: YAG laser in the presence of ~2 mm thickness of water and polyvinyl chloride to absorb the intensity and provide residual stress without surface damage. Electrochemical and hydrodynamic analyses indicate that the peened surface showed higher corrosion resistance in 3.5 % NaCl compared to the unpeened.

Determination of the levels of heavy metal (Cu

The aim of this study is to determine the impact of crude oil spillage on soil and harvested tuber crops (cocoyam and cassava) in Mogho Community. Polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, xylene (BTEX) were investigated using Gas Chromatography-Flame Ionization Detector. Tuber crops and soils from crude oil impacted area of Mogho Community were used as the sample; while soil not impacted by crude oil were collected from Bori was used as the control. The results obtained for PAHs showed mean concentration of 0.035mg/kg for polluted soil; 0.001mg/kg for cassava, and 0.005mg/kg for cocoyam harvested from the polluted soil while the unpolluted soil (control) had a mean concentration of 0.002mg/kg. The mean concentration of BTEX for the samples was <0.001 which is below detection limit. The presence of PAHs in samples was found to be both low molecular weight and high molecular weight. The PAHs found in the polluted soil was higher compared to that of the unpolluted soil. The concentration of PAHs found in samples, exceeds the recommended permissible limit of WHO standard, which is (0.0001mg/kg). These results reveal that crude oil pollution is responsible for the presence of PAHs in soils and tuber crops like cassava and cocoyam which are frequently consumed in our localities. Government and oil companies should employ mitigating measures to deal with pipeline vandalization and oil spillage in this area.

No abstract

Studies of the presence of heavy metals were carried out on some vegetables and crops harvested from farms in Ebocha, Egbeda and Igbo-Etche in Rivers State, Nigeria. These farms are located in communities where oil exploration activities are ongoing. The samples were prepared by wet digestion using a mixture of Perchloric acid (HClO 4): Nitric acid (HNO 3) in the ratio 1:4 and analyzed using Atomic Absorption Spectroscopy (AAS). The heavy metals concentration in almost all the vegetables and crops studied were high compared to the maximum permissible limits prescribed by World Health Organisation (WHO), Food Agriculture Organization (FAO) and