Browsing by Author "Mjemah, Ibrahimu C."

Now showing 1 - 2 of 2

Nitrate pollution of Neogene alluvium aquifer in Morogoro Municipality, Tanzania.
(International Formulae Group, 2011-02) Kibona, Irene; Mkoma, Stelyus L.; Mjemah, Ibrahimu C.
Concern over nitrate pollution of groundwater in integrated water quality management has been growing recently. The levels of nitrate in wells from septic tanks and urban agriculture with nitrogen fertilizers application may increase the potential groundwater pollution by nitrate. The purpose of this study was to determine the concentrations and spatial distribution of nitrate (NO 3 − ) in groundwater in Morogoro Municipality. Groundwater samples were collected from 20 wells during wet season period in March-April 2010 in 6 wards namely Kihonda, Mji Mpya, Mafisa, Saba Saba, Boma and Kilakala. The spectrophotometer was used to measure the NO 3 − concentration in water samples. The minimum and maximum nitrate levels were 1.4 and 32.5 mg/L respectively in the wards studied with an average of 7.76 mg/L. These results showed that all of the groundwater samples have NO 3 − concentration below the Tanzania Bureau of Standards upper limit value and World Health Organization guideline of 75 mg/l and 50 mg/l respectively. Also, the level of nitrate concentration tend to decrease with depth for most of the places due to the anoxic condition that is available at the higher depth which facilitates the utilization of nitrate by anaerobic microorganisms.
The use of the DRASTIC-LU/LC model for assessing groundwater vulnerability to Nitrate contamination in Morogoro municipality, Tanzania.
(MDPI Earth, 2022-11-07) Mkumbo, Neema J.; Mussa, Kassim R.; Mariki, Eliapenda E.; Mjemah, Ibrahimu C.
Groundwater is a useful source of water for various uses in different places. The major challenge in the use of this resource is how to manage and protect it from contamination. The current study was conducted in Morogoro Municipality to identify vulnerable groundwater areas by using DRASTIC-LU/LC model. The study applied eight input parameters, i.e., depth to water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, hydraulic conductivity and land use/land cover patterns, which were overlaid in GIS to generate groundwater vulnerable map. The model used rating (R = 1–10) and weighting (W = 1–5) techniques to assess the effect of each parameter on groundwater contamination. The DRASTIC-LU/LC Vulnerability Index map was classified into low- (area = 29.2 km 2 ), moderate- (area = 120.4 km 2 ) and high-vulnerability zones (area = 124.4 km 2 ). Nitrate analysis was conducted using the cadmium reduction method (DR 890) to assess the validity of the model and it was observed that 55%, 15% and 50% of the samples with unacceptable (>50 mg/L), high (29–50 mg/L) and moderate (14–28 mg/L) nitrate concentrations, respectively, fall into the high-vulnerability zone. Furthermore, 45%, 70% and 50% of the samples with unacceptable, high and moderate nitrate concentrations, respectively, fall into the moderate- vulnerability zone. In the low-vulnerability zone, only 15% of samples were found with a high nitrate concentration.