African Journal of Environmental Science and Technology 

About: African Journal of Environmental Science and Technology is an academic journal published by Academic Journals. The journal publishes majorly in the area(s): Water quality & Population. It has an ISSN identifier of 1996-0786. It is also open access. Over the lifetime, 1017 publications have been published receiving 13865 citations. The journal is also known as: AJEST.

Impacts of climate change, variability and adaptation strategies on agriculture in semi arid areas of Tanzania: the case of Manyoni District in Singida Region, Tanzania.

Abstract: A study was carried in two villages of Kamenyanga and Kintinku of Manyoni District, central Tanzania. The overall objective of this study was to understand local communities’ perceptions on climate and variability issues and establish its impacts and adaptation strategies within agricultural sector. Both secondary and primary were used. Primary data were obtained using different Participatory Research Approaches (PRA) including, focus group discussions and household questionnaires. In each village, a sample size of 10% of all households was interviewed. Findings showed that local people perceived changes in rainfall and temperature. The changes have affected crops and livestock in a number of ways resulting in reduced productivity. Empirical analysis of rainfall suggest decreasing rainfall trend between 1922 and 2007 whereas mean maximum and minimum temperature increased by 1.9 and 0.2°C respectively. The average annual temperature increase of 0.7°C between 1984 and 2004 was realized. There are different wealth groups namely the rich, the middle and the poor and these are differently vulnerable climate change. The study concluded that, the wealth of knowledge on coping and adaptation that farmer has should form a foundation for designing agricultural innovation systems to deal with impacts of climate change and variability. Further, development initiatives at community level in semi arid areas should put more emphasis on water harvesting to ensure water storage for crops and livestock. Key words: Agriculture production, climate change, Kamenyanga village, Manyoni District, rainfall, Singida Region.

The linkages between land use change, land degradation and biodiversity across East Africa.

Abstract: Land use changes in East Africa have transformed land cover to farmlands, grazing lands, human settlements and urban centers at the expense of natural vegetation. These changes are associated with deforestation, biodiversity loss and land degradation. A synthesis of results of long term research by an interdisciplinary team reveals the linkages between land use change, biodiversity loss and land degradation. The results indicate that as native vegetation is lost, indigenous plant and animal biodiversity and plant cover are lost. Pastoralism maintains native plant and animal species more effectively than crop cultivation. As croplands expand, soil fertility and moisture drops and soils erode more easily. Farmers who grow many crops conserve native plant species better than those who grow only one crop. Increased crop diversity encourages regeneration of indigenous plant species. Moderate farming as in the less intensive low input rainfed mixed crop farming, in less forested areas increases tree cover thus increasing the biodiversity. Farmers’ who combine livestock rearing with cropping, use livestock manure to replenish soil nutrients in their farms and are thus able to maintain higher productivity. Farming in grasslands, woodlands and bushland areas where there are fewer trees, increases the diversity of habitats due to introduction of agrosystems that attract new species of birds. However, if the farming is intensified and the diversity of habitats is reduced biodiversity is also reduced. This paper presents findings of the investigations on these linkages in a diverse farming and herding systems ranging from lowlands to high mountains land uses.

Assessment of heavy metal pollution in soils along major roadside areas in Botswana

Abstract: Assessment of heavy metal pollutants: Al, Co, Cu, Fe, Pb, Mn, Ni and Zn was conducted along major roadside soils of Botswana, lying between latitudes 18°S to 27°S and longitudes 20°E to 29°E using enrichment factor ratios (EF), contamination factor (CF), pollution load index (PLI) and geoaccumulation index (Igeo) methods. The studied sites were demarcated into five zones referred to as FN (Francistown-Nata), NM (Nata-Maun), MG (Maun-Ghanzi), GK (Ghanzi-Kang) and TS (Tshabong-Sekoma). All the four pollution assessment methods revealed that zones FN, NM and MG are pollution impacted as compared to GK and TS zones. Results of multivariate analysis suggest mixed origins of pollution sources including human activities, vehicular emissions and lithogenic occurrences. Al, Cu, Fe, Mn, Zn and Co is of mixed origins of pollutants, with Fe and Mn being predominantly lithogenic, and vehicular emissions characterised by Pb and Ni. The findings in this study will serve to create awareness of vehicular heavy metal pollution to Botswana policy makers in the mitigation of vehicular pollution, as it is barely monitored. Key words: Heavy metal contamination, roadside soils, enrichment factors, contamination factor, pollution load index, geoaccumulation index, cluster analysis, factor analysis.

Assessment of groundwater contamination in an industrial city, Sialkot, Pakistan

Abstract: Contamination of groundwater due to heavy metals is one of the most important concerns that have received attention at regional, local and global levels because of their toxicological importance in ecosystems and impact on public health. The present study was designed to assess the quality of groundwater in relation to heavy metal pollution and its implication on human health. The groundwater quality of Sialkot, an industrial city of Pakistan, was evaluated using water samples collected from 25 localities during October-November 2005. Twenty-two physiochemical parameters including pH, Electric Conductivity (EC), Total Dissolved Solids (TDS), Salinity, Temperature, Turbidity, Sulfate (SO4) Chloride (Cl), Total Hardness, Iodide, Fluoride, Ferric (Fe+3), Nitrate (NO3), Manganese (Mn), Total Chlorine, Alkalinity, Zinc (Zn), Lead (Pb), Iron (Fe), Copper (Cu), Nickel (Ni) and Chromium (Cr) were recorded. The results were compared with standard guidelines of World Health Organization (WHO) and Pakistan Standard Quality Control Authority (PSQCA) for groundwater quality. Cluster Analysis (CA) grouped all sites into four zones based on spatial similarities and dissimilarities of physiochemical properties. Zone 1 was highly ontaminated with high level of turbidity; EC, TDS, SO4, Cl, total hardiness, Zn, Pb and Fe concentrations were above the permissible levels of WHO and PSQCA. Cr+6 was detected in nineteen sampling sites and its concentration ranged between 0.01 - 0.30 mg/L. Factor Analysis (FA) and Discriminant Analysis (DA) revealed significant variables including pH, EC, TDS, SO4, NO3, Cl, Total Hardness, Iodide, Total Chlorine, Fluoride, alkalinity, Pb, Fe and Mn which are responsible for variations in groundwater quality and affect water chemistry. The results revealed that the groundwater of the study area cannot be considered of good quality as it is highly turbid (57% of total sites) with high level of Zn, Fe and Pb, which were above WHO and PSQCA permissible limits. The spatial distribution maps of water quality parameters were produced using Geographic Information System (GIS). The distribution maps served as important information to understand ecological status of the groundwater systems and for the identification of groundwater quality parameters withconcentration above the allowable limits of WHO and to fin d out potential areas where water treatment plants/technologies can be targeted in Sialkot.

Vulnerability and adaptation of rain fed agriculture to climate change and variability in semi-arid Tanzania.

Abstract: A vulnerability assessment of rain fed agriculture to climate change and variability in semi-arid parts of Tabora Region in Tanzania was conducted in 2009. Four village clusters were selected out of which, three villages represent Millennium Villages Program (MVP) namely Mbola, Mpenge and Isila from Uyui District. One village namely Tumbi from Tabora Urban bordering the MVP was also selected. Both primary and secondary data were collected using different methods including structured questionnaire interviews, focus group discussion, documentary review and field observations. Structured questionnaire interviews were administered to 7% of all farmers selected at random from the four villages and 30 research and extension officers obtained through accidental purposeful sampling. Simple regression and t-test analyses of numeric data for rainfall and temperature collected over the last 35 growing seasons were performed using Microsoft Excel and Statistical Analysis System respectively. Non-numeric data were coded, summarized and analyzed using Statistical Package for Social Sciences spreadsheet. Results indicate that the overall rainfall amount was found to decline while distribution was varying both in time and space. Inter-seasonal dry spells between January and February appeared to increase both in duration and frequency. Temperature has shown an increasing trend. Minimum temperature increased faster (R 2 = 0.68, p<0.001) while maximum temperature increased gradually (R 2 = 0.24, p<0.01). Farmers, research and extension officers also perceived these changes by the help of a series of indicators. Nevertheless, perception on the climate change indicators varied depending on the type of livelihood activity most affected. Major implications on rain fed agriculture are possible shrinking of the growing season, increasing moisture and heat stress to common food and cash crops, increased insects and pests and eventually low income and food insecurity. This study concludes that there is strong evidence demonstrating the vulnerability of rain fed agriculture to negative impacts of climate change and variability in the study area. It is suggested that there is a need for multi-level interventions on adaptation to climate change and variability taking into account a wide range of stakeholder involvement.