TITLE:
Investigation of the Physico-Chemical Standards of the Ground Waters around Mai-Bella Area in Asmara
AUTHORS:
Goitom Kfle, Mussie Sium, Arumugam Manohar, Semere Debretsion, Aron Tesfamariam, Nahom Tesfalem, Abel Okbaselasie, Kibrom Tesfay
KEYWORDS:
Mai-Bella, Groundwater, Physico-Chemical, Heavy Metals
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.7 No.9,
September
26,
2019
ABSTRACT: There are many possible sources of ground water contamination and may include wastes from industrial chemical production, domestic wastewater and pesticide run off from agricultural lands. The groundwater is thus susceptible to chemical, physical and/or microbiological contamination and ultimately becomes a cause for diverse diseases borne from the contaminated water. It has been a common practice to cultivate vegetables, crops and animal feed grasses around Asmara using sewage and industrial effluents and there are likelihoods that contaminants in the wastewater used for irrigation would infiltrate to the nearby wells. It is believed that the groundwater around the wastewater irrigated area is not safe for domestic and agricultural applications. Thus, this study was conducted to evaluate the quality of the groundwater in order to safeguard the public health treats caused by using this water. Samples were collected from five locations around Mai-Bella and thus different physico-chemical parameters were investigated. The pH of the samples was measured by pH metric method; electrical conductivity (EC) and salinity by using conductometric method. Hardness was estimated by EDTA method; total alkalinity (TA) and bicarbonate concentrations by titrimetric methods. Chloride concentration was analyzed by titration against mercurial nitrate. Na and K were determined using flame photometric method. Fe, Mn, nitrate, nitrite, sulphates and ammonia were determined using spectrophotometric method. Chemical Oxygen Demand (COD) was determined using photometric method. Moreover, the concentrations of trace, major and heavy metals were analysed using Inductively Coupled Plasma Optical Emission Spectrophotometer (ICP-OES). The suitability of the groundwater for domestic and irrigation purposes was examined using WHO and FAO standards. Most of the physico-chemical parameters, except the temperature, pH, COD, Al, Cd, Cr, Cu and Zn, of the samples were found above the standard limits given by WHO. Similarly, the levels of toxic metals (Pb, As, Hg and Se) in all the water sources and Ni from two water sources were found above the permissible limit. Accordingly, the results signpost that most of the groundwater samples from the study sites are not suitable for drinking and irrigation purposes. Further studies related to the bacterial load would be appropriate to assess the health effects of all the water sources found around Mai-Bella.