A novel adsorbent for heavy metal remediation in aqueous environments

The objective of this study was to investigate the possibility of using maize tassel as an alternative adsorbent for the removal of chromium (VI) and cadmium (II) ions from aqueous solutions. The effect of pH, solution temperature, contact time, initial metal ion concentration and adsorbent dose on the adsorption of chromium (VI) and cadmium (II) by tassel was investigated using batch methods. Adsorption for both chromium (VI) and cadmium (II) was found to be highly pH dependent compared to the other parameters investigated. Obtained results gave an adsorption capacity of 79.1 % for chromium (VI) at pH 2, exposure time of 1h at 25 °C. Maximum capacity of cadmium of 88 % was obtained in the pH range of 5-6 at 25 °C after exposure time of 1 h. The adsorption capacities of tassel for both chromium (VI) and cadmium (II) were found to be comparable to those of other commercial adsorbents currently in use for the removal of heavy metals from aqueous wastes. These results have demonstrated the immense potential of maize tassel as an alternative adsorbent for toxic metal ions remediation in polluted water and wastewater.     

It's not all about wealth and beauty: Changing perceptions of fatness among Makola market women of Accra,Ghana

Within the African context, body shape preferences may be influenced by culture without necessarily taking into consideration health implications. Thus, fatness is culturally associated with beauty, prosperity, and prestige while thinness is perceived as a sign of ill‐health or poverty. Using a cross section of Makola market women, who traditionally are perceived as fat and affluent, our findings revealed that the perception of fatness as a sign of richness and beauty is changing due to women's access to knowledge and information on the health implications of fatness. The challenge for these women however, is adhering to healthy lifestyles despite living sedentary lives in the market place which is a conducive environment for one to become fat. We recommend that qualified professionals should encourage these women through continuous programmes on regenerative health and nutrition aimed at healthy lifestyle behaviour at the market places. The social groups that women belong to should be targeted, trained and equipped with the right information on healthy living so that they can disseminate this information to other members of their networks.     

Quantitative evaluation of strategies for erosion control on a railway embankment batter

Strategies for erosion control on a railway embankment batter (side slope) are quantitatively evaluated in this paper. The strategies were centred on control (‘do nothing’ treatment), grass seeding, gypsum application, jute mat (an erosion control blanket) placement and planting hedgerows of Monto vetiver grass. Rainfall and runoff were monitored at 1 min intervals on 10 m wide embankment batter plots during 1998 and 1999. Total bedload and suspended sediment eroded from the plots were also measured but only for a group of storm events within sampling intervals. It has been demonstrated that vetiver grass is not cost‐effective in controlling erosion on railway batters within Central Queensland region. Seeding alone could cause 60% reduction in the erosion rate compared with the control treatment. Applying gypsum to the calcium‐deficient soil before seeding yielded an additional 25% reduction in the erosion rate. This is the result, primarily, of 100% grass cover establishment within seven months of sowing. Therefore, for railway embankment batter erosion control, the emphasis needs to be on rapid establishment of 100% grass cover. For rapid establishment of grass cover, irrigation is necessary during the initial stages of growth as the rainfall is unpredictable and the potential evaporation exceeds rainfall in the study region. The risk of seeds and fertilizers being washed out by short‐duration and high‐intensity rainfall events during the establishment phase may be reduced by the use of erosion control blankets on sections of the batters. Accidental burning of grasses on some plots caused serious erosion problems, resulting in very slow recovery of grass growth. It is therefore recommended that controlled burning of grasses on railway batters should be avoided to protect batters from being exposed to severe erosion. Copyright © 2001 John Wiley & Sons, Ltd.     

Modelling diurnal cycles in point rainfall properties

A hybrid model for point rainfall has been explored to model the diurnal cycles in rainfall properties. The hybrid model is a product of two random processes: an occurrence process and an intensity process. Two occurrence process models, first‐order Markov chain and periodic discrete autoregressive, were compared initially. Fourier series was fitted to the properties of the occurrence and intensity processes of the observed data in order to reduce the number of model parameters. The Bayesian and Akaike information criteria were used to identify the optimum number of harmonics of the Fourier series. Simulation results of the two hybrid models were similar, if not identical, and compared well with the observed. In the average sense, the introduction of diurnal cycles in the model parameters did not improve the reproduction of the observed aggregation properties of the occurrence process. However, the diurnal distributions of the aggregation statistics were significantly improved by increasing the order of the Markov chain model. Also the information criteria tend to favour higher than first‐order Markov chain models. Copyright © 2001 John Wiley & Sons, Ltd.     

Is better to be a kayayei than to be unemployed: reflecting on the role of head portering in ghana’s informal economy

The implementation of neoliberal economic reforms with its resultant effects on rural agricultural economies has facilitated the migration of young girls from northern to southern Ghana to seek for alternative livelihoods in the urban informal economy as head porters (Kayayei). Using semi-structured questionnaires and interviews with 45 Kayayei in Makola and Agbogbloshie Markets, Accra, this study examines how migration as a livelihood strategy contributes to an improvement in the living conditions of young girls and their families. The paper also looks more closely into the pathways through which the livelihoods of these young female migrants may contribute to local economic development. The study highlights that Kayayei contribute to local economic development through market exchange and revenue generation, also there is significant perceived positive impact of head portering on standard of living of these young girls through improved access to income, health care and asset accumulation while their families benefit from remittances. The study concludes by advocating for the need to provide access to credit and skills training in enhancing the livelihood of Kayayei.     

Effects of Planting Field on Groundwater and Surface Water Pollution in China

Water forms an essential resource for life on earth because all living things on earth depend on water for life activities. However, with the increase in the human population, which is coupled with intense urbanization and agricultural activities, global water pollution has increased over the past decades. In China, agricultural activities that occure mainly in the planting fields have been listed as the main source of surface water and groundwater pollution. This review focuses on the major factors that influence pollution from planting fields in China mainly as a result of farming activities such as flood irrigation, excessive application of fertilizers and pesticides, and poor management practices. At present, good results are achieved by adopting soil fertilization test formula, biodegradable pesticides, proper irrigation, and agroforestry interventions. In the future, pollution from planting fields as a non‐point source of water pollution can be improved and resolved by perfect nutrient management, best management practices, organic amendments, restoring water environment, and intelligent assessment management.