Browsing by Author "Lema, Emmy"

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Agrochemicals use in horticulture industry in Tanzania and their potential impact to water resources
(International Journal of Biological and Chemical Sciences, 2014-04) Lema, Emmy; Machunda, Revocatus; Njau, Karoli
The objective of this review was to analyze the existing information on the use of agrochemicals (Fertilizers and Pesticides) in the Tanzanian horticulture industry especially the Northern regions and their potential to impacting water resources. Agrochemicals play an important role in horticulture, and have been widely used in Tanzania for crop protection and increasing productivity. Apart from these benefits, agrochemicals have the potential to impair the quality of water resources for different end uses. Majority of communities in Tanzania depend on surface water from rivers and lakes for potable uses such as washing, drinking and domestic animals also drink from these sources. Reports from studies done in Northern Tanzania have indicated the presence of significant levels of pesticides, phosphates and nitrates in surface and groundwater. It is apparent that most of the horticultural farms in Northern Tanzania are located on gently sloping land adjacent to water bodies. Thus discharges of wastewaters from horticulture farms may affect the quality of water resources through run-off and groundwater through infiltration if proper management of the agrochemicals is not well adhered to. The agrochemicals that have been widely used and identified as potential environmental pollutants from their use as horticultural chemicals are reviewed. The potentially adverse impacts of these agrochemicals to water resources are discussed. The review concludes with a discussion of the directions for further investigation.
Influence of Macrophyte Types towards Agrochemical Phytoremediation in a Tropical Environment
(International Journal of Engineering Research and General Science, 2014-09) Lema, Emmy; Machunda, Revocatus; Njau, Karoli
The presence of agrochemicals waste water from agricultural fields poses major environmental and human health problems which may be solved by phytoremediation technologies. Phytoremediation is the use of plants to remediate contaminants in the environment. Batch experiments were conducted to evaluate the influence of four aquatic macrophytes (Cyperus papyrus, Typha latifolia, Cyperus alternifolius and Phragmites mauritianus) towards phytoremediation of agrochemicals from simulated wastewater in Arusha, Tanzania. The selected agrochemicals belonged to different categories namely heavy metal based (Cu, Fe, Mn and Zn) and pesticides (L-Cyhalothrin, Endosulfan and Permethrin). The change in mean concentration of the agrochemicals was described by first-order reaction kinetics. The results indicated that the removal rate constants were greater for the batch experiments planted with the macrophytes than for the control group. Furthermore, the rate of removal varied between the treatments for the different categories of agrochemicals. As far as heavy metals are concerned, Cyperus papyrus had a greater removal Cu and Fe with the k values of 0.338 d-1 and 0.168 d-1 respectively and Typha latifolia had a greater removal of Mn and Zinc with k values 0.420 d-1 and 0.442 d-1 respectively. On the other hand, the pesticides endosulfan and permethrin were greatly removed by Cyperus papyrus with k values 0.086 d-1 and 0.114 d-1 respectively. Lastly, L-Cyhalothrin was removed greatly by Typha latifolia with k value of 0.116 d-1. Generally, the results demonstrated that aquatic macrophytes can influence the reduction of agrochemicals in wastewater