Spices and herbs are being added to diet as ingredients often to improve color, aroma and acceptability of food. The presence of heavy metals in spices could result in the accumulation of these metals in the body organs. The amount of essential and non-essential heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in spices commonly used in Eritrea were determined using a dual viewing ICP-OES. Fe was found to have the highest concentration of all the studied metals in all studied spices that ranged from 197-2364 mgkg-1. Co was found to be the least accumulated metal in all the species except in Rosemarie and Cinnamon. The level of Fe in all the studied spices (except Cinnamon), the level of Cd in Cumin and Cinnamon, the level of Cu in Allspices, the level of Mn in Black pepper, Allspices, Nutmeg and Cinnamon, the level of Pb in Turmeric and the level of Zn in Nutmeg were found above the WHO Maximum Permissible Limit (MPL). Cumin, Cinnamon, Black pepper and Nutmeg are constituents of the spice called Allspices. Allspices (comprising of almost fourteen spices) is added to berbere which is traditionally prepared and most consumed powder in Eritrea. Cumin was found to be the greatest accumulator of Co, Cr, Ni and Fe. Moreover, the levels of Cr and Cu in Cumin were alarming. Therefore, based on the results of this study consumption of Cumin, Cinnamon, Allspices, Black pepper and Nutmeg may have a serious health threat to consumers because berbere is consumed in large amount and with high frequency by Eritrean people. Based on the results of this study, it is recommended that either the consumption of berbere has to be reduced or the addition of spices to berbere has to be controlled.
Soils irrigated with wastewater are by and large contaminated with heavy metals, and consumption of vegetables and animal feed grasses grown in contaminated soils have been a major food chain route for human exposure and pose a health hazard. A study was conducted in three sites to assess the accumulation of heavy metals in farms irrigated with wastewater between two and five decades in and around Asmara, Eritrea. The concentrations of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, V, and Zn) in soils and plants (Medicago sativa L., Avena sativa L., Cynodon dactylon L., Corchorus olitorius L., and Cynara scholymus L.) grown in the farms were analyzed using an inductively coupled plasma optical emission spectrophotometer (ICP-OES). Multivariate analysis, such as principal component analysis (PCA) and cluster analysis (CA), was performed on the distribution of elements in plant species to identify the source of the heavy metals. The level of the metals in the soil samples was in the order of Mo < Cd < Co < Cu < Pb < V < Cr ≈ Zn < Mn < Fe < Al. The order of the metals in the plants of the different sites has been, in general, Cd < Co < V < Cr < Pb < Cu < Zn < Mn < Al < Fe. The study revealed that the soil samples of the studied sites were unsafe for agricultural purposes with respect to Fe, Mn, and Pb except for Pb in the case of the soil sample from the Kushet area. The levels of most of the studied heavy metals in the vegetation samples from all the sites were found within the FAO/WHO permissible limit. Al and Fe exceeded the FAO/WHO permissible limit with the exception of all plant samples from the Kushet area and M. sativa from Paradizo. The concentration of Al was also below the limit in C. dactylon from Adi-Segdo and Paradizo. Of the five vegetation considered in this study, C. olitorius was found to be a good accumulator and C. dactylon, the lowest accumulator of heavy metals. Based on the results of this study, the grass species C. olitorius should be further investigated for its phytoremediation capability of contaminated soils. The results of the multivariate analysis revealed that Fe, V, Al, Cr, Co, and Pb were controlled by mixed (natural and anthropogenic) sources and Zn, Mo, Cu, Mn, and Cd originated from the anthropogenic source. Very limited and inadequate studies were conducted on the accumulation of heavy metals in plants grown in wastewater irrigated farms around Asmara. Therefore, the results of this study are expected to shed light on the understanding of the community and enable the City Council to monitor the environmental quality and take appropriate actions.
The degradation of organic-inorganic hybrid materials based on epoxy resin was characterized electrochemically in aggressive chemical electrolyte. In the present study, the hybrid material as primer was prepared from epoxy resin pigmented by zinc phosphate cured with polyamide (EPZ). The hybrid material was coated on mild steel substrate, and the corrosion behavior was studied by electrode-potential time measurements and mainly by electrochemical impedance spectroscopy (EIS) in 5% NaCl solution. The impedance parameters, namely, coating capacitance (C c ), pore resistance (R po ), charge transfer resistance (R t ), double layer capacitance (C d1 ), and break point frequency ( f b ), corresponding to 45• phase angle as a function of time of exposure were estimated. The observed impedance behavior were compared with the established equivalent electrical circuit represents the coated metal/electrolyte interface. Changes in the values of the circuit components given the information on the stages of degradation and physical phenomenon occurring throughout the degradation of primer coating were also been predicted. In addition, information related to the porous nature of the primer, limited passivation effect, and delamination of coating with longer exposure that resulted in the diffusion controlled corrosion of metal are also recognized. Thus, results indicate that the EPZ coating had good corrosion resistance. This could be a nonpolluting alternative to the traditional chromate like environmentally harmful coatings.
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