scholarly journals Sources of Nitrate in Ground Water Aquifers of the Semiarid Region of Tanzania

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Rita Alex ◽  
Aldo Kitalika ◽  
Emmanuel Mogusu ◽  
Karoli Njau
Keyword(s):  
Ground Water ◽  
Water Sources ◽  
Semiarid Region ◽  
Wet Season ◽  
Nitrate Sources ◽  
Mean Values ◽  
Sewage Effluents ◽  
Nitrification Process ◽  
Shallow Wells ◽  
The Mean

Nitrate isotopic values are often used as a tool to identify sources of nitrate in order to effectively manage ground water quality. In this study, the concentrations of NO3−, NO2−, and NH4+ from 50 boreholes and shallow wells in the Singida and Manyoni Districts were analyzed during the dry and wet seasons, followed by identification of nitrate sources using the hydrochemical method (NO3−/Cl−) and stable isotope (δ15N and δ18O) techniques. Results showed that NO2− and NH4+ concentrations were very low in both seasons due to the nitrification process. The concentrations of NO3− ranged from 2.4 ppm to 929.6 ppm with mean values of 118.5   ppm ± 118.5   ppm , during the dry season and from 2.4 ppm to 1620.0 ppm with mean values of 171.6   ppm ± 312.3   ppm , during the wet season. The higher NO3− contamination observed in the wet season could be due to rainfall which accelerated the surface runoff that collects different materials from various settings into the ground water sources. Nitrate source identification through hydrochemical technique revealed that most nitrates originated from sewage effluents and/or organic wastes such as manure. Likewise, the mean values of δ15N-NO3− ( + 20.90 ‰ ± 5.17 ‰ and + 18.30 ‰ ± 6.33 ‰ ) and the mean values of δ18O-NO3−( + 13.86 ‰ ± 3.18 ‰ and + 13.69 ‰ ± 3.97 ‰ ) suggest that 80% of boreholes and 52% of shallow wells were dominated with nitrate from sewage effluents and/or manure as most ground water sources were situated in densely populated areas with congested and poorly constructed onsite sanitation facilities such as pit latrines and manure. Therefore, to reduce nitrate pollution in the study area, a central sewer must be constructed to treat the discharged wastes. Also, groundwater harvesting should consider the proper principles for groundwater harvesting recommended by the respective authority to minimize chances of contamination and hence prevention of health risk.

scholarly journals Heavy metal levels in drinking water sources of Chingola District, Zambia

2020 ◽  
Author(s):  
Francis Hamwiinga ◽  
Chisala D. Meki ◽  
Patricia Mubita ◽  
Hikabasa Halwiindi
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Drinking Water ◽  
Ground Water ◽  
Water Samples ◽  
Tap Water ◽  
Water Sources ◽  
Wet Season ◽  
Drinking Water Sources ◽  
Metal Levels

Abstract Background: One of the factors impeding access to safe water is water pollution. Of particular concern is heavy metal contamination of water bodies. This study was aimed at determining the levels of heavy metals in drinking water sources of Chingola District of Zambia. Methods: A cross sectional study was employed. A total of 60 water samples were collected. Thirsty (30) samples were collected in the dry season in the month of October 2016 and another 30 in the wet season in the months of February and March, 2017. For each season 10 water samples were collected from each of the three water sources. i.e. Tap water, Urban ground water sources and Rural ground water sources. Heavy metal analysis was done using Atomic Absorption Spectrophotometer (AAS).Results: This study revealed that the concentrations of Iron, Manganese, Lead, Nickel and Arsenic were beyond maximum permissible levels in various water sources. Combined averages for both dry and wet seasons were as follows: Iron: 2.3, Copper: 0.63, Cobalt: 0.02, Manganese: 0.36, Lead: 0.04, Zinc:3.2, Nickel: 0.03, Arsenic: 0.05. Chromium and Cadmium were below detection limit in all water samples. The median concentrations of iron, arsenic, copper, manganese in drinking water from the Tap, rural and urban ground water sources were different, and this difference was statistically significant (p<0.05). The median concentrations of arsenic, nickel, manganese and cobalt were different between dry and wet season, and this difference was statistically significant (p<0.05).Conclusions: Sources of heavy metals in water seems to be both natural and from human activities. The concentration of heavy metals in different water sources in this study was found to be above the recommended levels. This calls for improvement in water monitoring to protect the health of the public. Therefore, there is need for continuous monitoring of heavy metals in drinking water sources by regulatory authorities.

scholarly journals Surface Layer Turbulent Characteristics over the Complex Terrain of the Loess Plateau Semiarid Region

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhida Zhang ◽  
Jiening Liang ◽  
Min Zhang ◽  
Qi Guo ◽  
Lei Zhang
Keyword(s):  
Surface Layer ◽  
Transfer Coefficient ◽  
Loess Plateau ◽  
Turbulence Intensity ◽  
Complex Terrain ◽  
Semiarid Region ◽  
The Loess Plateau ◽  
Mean Values ◽  
The Mean ◽  
Standard Deviations

Surface layer turbulence has an important influence on land-air interactions and pollutant dispersion, and studying the characteristics of surface layer turbulence in complex terrain can contribute to understanding land-air interactions, improving model surface layer parameterization, and enhancing pollution prediction capabilities. The surface layer turbulence observations from the Semi-Arid Climate and Environment Observatory (SACOL) of Lanzhou University in 2008 were processed in this study. High-quality turbulence parameters were calculated, the statistical and transfer characteristics of turbulence were analyzed, and the formation of turbulence was assessed in terms of dynamics and thermodynamics. The atmospheric stability in the semiarid region of the Loess Plateau is basically dominated by neutral/near-neutral and weakly unstable/weakly stable conditions; this pattern is significantly different from the preponderance of unstable and stable layers at other sites. The turbulence intensity differs significantly in both the horizontal and vertical directions and basically shows the relationship I u ≈ I v > I w . The mean values of I u and I v are 0.42 and 0.40, respectively, and the mean value of I w is 0.14, which is different from the general pattern of I u > I v > I w , indicating that the turbulence intensity at SACOL is characterized by a large lateral wind contribution. The dimensionless standard deviations of the nonneutral wind velocity components satisfy the “1/3rd law,” and the dimensionless standard deviations of u, v , and w components are 3.35, 2.98, and 1.26, respectively, in the semiarid Loess Plateau. These values are larger than those over flat terrain. The contribution of the shear term to the formation of turbulence is greater than that of the buoyancy term, and the mean annual values of the shear term and the buoyancy in the kinetic energy budget equation in SACOL are 47.94 × 10−4 m2·s−3 and 11.32 × 10−4 m2·s−3, respectively. The annual mean values of the momentum transfer coefficient C D and the heat transfer coefficient C H under near-neutral conditions are 8.54 × 10−3 and 2.52 × 10−3, respectively.

scholarly journals An investigation of water quality in shallow ground water sources in the Odaube area of Benue State, Nigeria

2014 ◽  
Vol 36 ◽  
Author(s):  
Ifeanyichukwu Clinton Ezekwe ◽  
Ahamefula Sunday Ezekwe ◽  
Ochekwu Austin Sunday
Keyword(s):  
Water Quality ◽  
Ground Water ◽  
Treatment Options ◽  
Water Sources ◽  
World Health ◽  
Chemical Additives ◽  
Domestic Water ◽  
The People ◽  
Shallow Wells ◽  
Health Organization

This study examined shallow ground water quality in Odaube, Benue State, Nigeria. Physico-chemical parameters (taste, odour, pH, conductivity, dissolved solids, hardness, alkalinity, acidity, Nitrate and chloride) and coliform communities were investigated. Generally, results obtained did not meet the acceptable standard of the World Health Organization for potable water. 80% of sampled water sources had odour and taste problems, 10% had pH problems while 20% had elevated nitrate concentrations. Also all the sampled sites showed evidence of serious microbial pollution. This stems from the poor hygienic conditions around water sources and proximity to pit latrines and waste dump sites. Over 90% of the people in the study area depend on these contaminated shallow wells for domestic water as such cheap water treatment options like boiling and the use of chemical additives like water Guard® is highly recommended.

scholarly journals Quality Assessment of Three Types of Drinking Water Sources in Guinea-Bissau

2020 ◽  
Vol 17 (19) ◽  
pp. 7254
Author(s):  
Aducabe Bancessi ◽  
Luís Catarino ◽  
Maria José Silva ◽  
Armindo Ferreira ◽  
Elizabeth Duarte ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Sources ◽  
Chromium Concentration ◽  
Residual Chlorine ◽  
Waterborne Diseases ◽  
Wet Season ◽  
Guinea Bissau ◽  
Piped Water ◽  
Shallow Wells ◽  
Important Health

The lack of access to safe drinking water causes important health problems, mainly in developing countries. In the West African country Guinea-Bissau, waterborne diseases are recognised by WHO as major infectious diseases. This study analysed the microbiological and physicochemical parameters of drinking water in the capital Bissau and its surroundings. Twenty-two sites belonging to different water sources (piped water, tubewells and shallow wells) were surveyed twice a day for three weeks, in both dry and wet seasons. Most of the microbiological parameters were out of the acceptable ranges in all types of water and both seasons and tended to worsen in the wet season. Moreover, in Bissau, the levels of faecal contamination in piped water increased from the holes to the consumer (tap/fountain). Several physicochemical variables showed values out of the internationally accepted ranges. Both well sources showed low-pH water (4.87–5.59), with high nitrite and iron levels in the wet season and high hexavalent chromium concentration in the dry season. The residual chlorine never reached the minimum recommended level in any of the water sources or seasons, suggesting a high risk of contamination. Results reveal a lack of quality in the three water sources analysed, coherent with the high number of diarrheal cases in the country. There is an urgent need to improve sanitarian conditions to reduce the disease burden caused by these waterborne illnesses.

scholarly journals Characteristics of artisanal fisheries in the upper reaches of Bonny Estuary, Niger Delta, Nigeria

2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Daniel Utibe I ◽  
Monsi BG
Keyword(s):  
Oxygen Demand ◽  
Fish Growth ◽  
Artisanal Fisheries ◽  
Chemical Parameters ◽  
Wet Season ◽  
Mean Values ◽  
Access To Credit ◽  
Physico Chemical ◽  
The Mean ◽  
Laws And Policies

Characteristics of artisanal fisheries in the upper reaches of Bonny Estuary were investigated for a period of six months from December 2014 to June 2015. Data were collected from randomly selected fishermen from five communities, viz., Bodo, Kpor, Bomu, Lewe and Gbe, using interview and open ended structured questionnaire. The research was carried out to ascertain the fish existed in the study area, types of gear, and methods of fishing, preservation and marketing techniques. The mean values of physico-chemical parameters such as temperature, dissolved oxygen (D.O), salinity, pH, turbidity, and biological oxygen demand (BOD) were 30.47±1.34˚C, 8.64±1.24 mg/l, 16.4±5.78 ppt, 7.66±0.76, 117.0±16.9 NTU and 4.94±2.66 mg/l, respectively. A total of 52 fish species belonging to 24 families were identified and the species diversity and their abundance were determined. Tilapia guineensis was the highest in number (190) with 4.0% of abundance, while Sphryraena afra was the least in number (9) with 2.0% of abundance. The dry season (December–February) recorded the number of 2,772 (57.7%) fin fishes, while the wet season (April–June) found 2,028 (42.3%). The mean number of fish caught was highest in station 2 and lowest in station 4. The physico chemical parameters were within the acceptable limits for fish growth in brackish water ecosystem. The study revealed that the gear commonly used by the fishermen include cast nets, drag nets, hook and line, and traps, while the crafts used were mainly dug-out canoe and non-motorised boat. It also revealed that the constraints responsible for the low catch and poor standard of living of the fishermen as observed include high cost of gear materials, poor condition of boat, no access to credit facilities, destruction of nets by engine boat and environmental pollution. In view of the negative impacts that the aforementioned factors have on the fishermen, it is necessary to implement an effective management of the fisheries through proper enforcement and environmental laws and policies to safeguard and conserve the aquatic biota from going into extinction as well as restoring the source of livelihood to the fishermen in the area under investigation.

A geospatial model for mapping desertification risk areas in the Caatinga biome, a semiarid region of Brazil

2020 ◽  
Author(s):  
Marcos César Ferreira ◽  
Mariana Monteiro Navarro de Oliveira ◽  
Danilo Carneiro Valente
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Logistic Regression Analysis ◽  
Vegetation Index ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Wet Season ◽  
Mean Values ◽  
Risk Areas ◽  
The Mean

&lt;p&gt;Desertification is a process characterized by the degradation and drying of soils in arid, semiarid and subhumid regions that results from a combination of climatic factors and human activities. This process influences the productivity potential of the soils, impacting the populations residing in the affected areas, and may cause long-term economic problems and impacts on human health, such as hunger and food insecurity. The aim of this paper is to present a geospatial model for mapping desertification risk areas in northeastern Brazil. The test area for the model was located in the Brazilian semiarid climatic region in the state of Cear&amp;#225;. In this area, the dry season lasts for 7 to 8 months, and the original vegetation belongs to the Caatinga biome. The model was based on algebraic operations between maps of environmental variables, performed in a geographic information system, and based on equations obtained through logistic regression analysis. First, 300 points were mapped in the centroids of desertification polygons (D), and 300 points were mapped in areas where no desertification processes (ND) had occurred. All points were selected by visual interpretation of Sentinel-2A multispectral images. Then, 500 m radius buffers were mapped around the centroids of the D and ND areas, and the mean values of the following environmental variables were extracted within these buffers: the average annual rainfall (RAIN), altitude (ELV), vegetation index dry season (VID), wet season vegetation index (VIM), dry season soil temperature (LTD), and wet season soil temperature (LTM). The mean values &amp;#8203;&amp;#8203;of the RAIN, ELV, VID, VIM, LTM and LTD variables for the D and ND areas were entered in the MedCalc software for logistic regression analysis. The &lt;em&gt;p&lt;/em&gt; probability map of desertification occurrence was constructed in ArcGIS Pro using equations for which the parameters were obtained with the logistic regression analysis. The results showed that the variables RAIN, ELV, VID and LTD (p &lt;0.0001) contributed significantly to the occurrence of desertification areas. The value obtained for the area under the ROC curve (AUC) parameter was 0.757, and the percentage of cases correctly classified by the model was 70.17%. In the next step of this research, this model will be tested on a larger area of 72,000 km&lt;sup&gt;2&lt;/sup&gt; that is located in the Jaguaribe River basin, northeastern Brazil.&lt;/p&gt;

Estimation of radon concentrations and associated radon doses by using active technique in drinking water sources of Abbottabad, KPK, Pakistan

2016 ◽  
Vol 27 (5) ◽  
pp. 682-689 ◽  
Author(s):  
F. Khan ◽  
Z. Wazir ◽  
N. Ali ◽  
S. A. Khattak
Keyword(s):  
Drinking Water ◽  
Surface Waters ◽  
Water Samples ◽  
Radon Concentration ◽  
Water Sources ◽  
Mean Values ◽  
Drinking Water Sources ◽  
The Mean ◽  
Active Technique ◽  
Radon Concentrations

In-situ measurement of radon concentration was carried out in three types of drinking water sources (spring, surface and bore/well). Water samples from all three sources were collected from the city of Abbottabad and its surroundings. Radon concentrations were measured through active technique, using the AB-5 series of portable radiation monitor (Pylon). The mean concentrations (ranges) of radon in the phosphate region were 13.4 ± 2.0 (9.1–23.6), 11.2 ± 1.5 (6.2–20.1) and 7.1 ± 0.9 (4.3–14) kBq m−3 in well, spring and surface waters, respectively. Similarly, the mean concentrations (ranges) of radon outside the phosphate region were 7.2 ± 1.0 (3.4–11.5), 5.4 ± 0.7 (2.5–8.9) and 3.1 ± 0.4 (1.7–5.8) kBq m−3 in well, spring and surface waters, respectively. The arithmetic mean values of radon concentration in drinking waters in the phosphate and non-phosphate parts or rocks were 10.76 ± 1.5 and 5.10 ± 0.70 kBq m−3, respectively. Respective doses of radon taken in by the people via water ingestion and inhalation were calculated as 0.029 ± 0.004 and 0.014 ± 0.002 mSv. The mean values of radon concentrations in drinking water samples collected from Abbottabad phosphate and non-phosphate rocks were below the US EPA Maximum Contamination Level (MCL) of 11.1 kBq m−3. The annual mean effective doses of all samples are lower than the reference level of 0.1 mSv a−1 for drinking water as recommended by WHO. Thus, the drinking water of Abbottabad and its surroundings is generally below the recommended levels as regards to radon-related health hazards.

scholarly journals Geospatial and Geostatistical Analyses of Particulate Matter (PM10) Concentrations in Imo State, Nigeria

2016 ◽  
Vol 57 ◽  
pp. 89-107 ◽  
Author(s):  
Alex Iheanyichukwu Opara ◽  
Francis Chizoruo Ibe ◽  
Pascal Chukwuemeka Njoku ◽  
Jude Ikechukwu Alinnor ◽  
Conrad Kenechukwu Enenebeaku
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Ambient Air ◽  
Dry Season ◽  
Air Pollutant ◽  
Wind Rose ◽  
Wet Season ◽  
Mean Values ◽  
Imo State ◽  
The Mean

Geospatial and geostatistical analysis of particulate matter (PM10) variation in Imo State, Nigeria was carried out. The objectives of the study were to determine and analyze the variation in concentration of ambient PM10level in Imo State, Nigeria. Air quality sampling was conducted within November 2014 and June 2015, in wet and dry seasons three times daily using Haze Dust Particulate Monitor (10μm). The mean concentration of PM10level observed in the study varied from 5.22 - 6.63 mg/m3in wet season and 5.80 - 8.38 mg/m3in dry season. Coefficient of variation (CV %) revealed that the variability of PM10level ranged between little and moderate variations in both wet and dry season. Analysis of variance (ANOVA p<0.05) showed statistically significant variation in the mean PM10level in the study locations. Box and Whisker plots confirmed variation of PM10in the morning, afternoon and evening. The GIS plots revealed the spatial attributes of the air pollutant in the study locations. Time series plots indicate that the air pollutants fluctuated throughout the study duration. The Wind Rose suggests that the prevailing wind speed and wind directions were responsible for the dispersal migration of the air pollutant in the study area. The highest seasonal mean values were observed in Egbema and Okigwe area in both dry and wet season. The seasonal mean values recorded in the study exceeded the Nigerian National Ambient Air Quality Standards. This calls for urgent response to prevent further air quality deterioration and its negative effects on man and the environment.

Studies on Stomoxys calcitrans (L.) in Uganda, East Africa. II.—Notes on life-history and behaviour

1962 ◽  
Vol 53 (2) ◽  
pp. 437-443 ◽  
Author(s):  
H. C. M. Parr
Keyword(s):  
East Africa ◽  
Laboratory Culture ◽  
Egg Laying ◽  
Stomoxys Calcitrans ◽  
Cattle Dung ◽  
Wet Season ◽  
Mean Values ◽  
The Third ◽  
Cent Relative Humidity ◽  
The Mean

Features of the development of Stomoxys calcitrans (L.) are described, based on observations in Uganda on stocks maintained in laboratory culture at 80°F. and 80 per cent, relative humidity. Eggs hatch within 24 hours of deposition, and the mean viability of 10 random batches was 76·5 per cent. The larvae are about 1 mm. long when newly hatched, reach maximum length (about 11 mm.) in the third (final) instar on the seventh day, and pupate one day later, the puparium being barrel-shaped and about 5 mm. long and 11 mg. in weight. The pupal period is two days. Females mate when six days old and oviposit 1–2 days later. The mean values, for five newly emerged, once-mated females, of total eggs laid, number of batches and duration of egg-laying (in days) were, respectively, 376, 10·6 and 12·2.To be suitable for breeding of Stomoxys in the field in East Africa, sites require the presence of rotted cattle dung, rotted straw or foliage, and shade. In the dry season, such conditions occur only within cattle enclosures and particularly in the small, grass-thatched structures, provided with straw bedding, that are used for housing calves. In the wet season, suitable breeding conditions occur in open park-land and banana plantations, wherever rotted cattle manure and vegetation occur together.

scholarly journals HEAVY METALS ANALYSIS OF MAI-ALLO POND IN GWALE LOCAL GOVERNMENT AREA, KANO STATE, NIGERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 16-21
Author(s):  
M. M. Karaye ◽  
H. A. Ibrahim
Keyword(s):  
Heavy Metals ◽  
Pond Water ◽  
Dry Season ◽  
Wet Season ◽  
Mean Values ◽  
A Value ◽  
Significant Difference ◽  
Dry Seasons ◽  
The Mean ◽  
Wet And Dry Seasons

Study of Seven heavy metals namely, Zinc, Lead, Copper, Cadmium, Manganese, Chromium and Nickel was conducted in Mai-Allo pond, Gwale, Kano State in order to assess the concentration of the heavy metals in the pond. The results of the heavy metals showed that Zn has a value of 0.34±0.17 mg-l in the wet season and 0.49±0.37 mg-l in the dry season, Cu has a value of 1.42±0.14 mg-l in the wet season and 0.64±0.09 mg-l in the dry season, and Ni also has 0.12±0.02 mg-l in the wet season and 0.23±0.13 mg-l in the dry season, all these were within acceptable limits, while Pb with a value of 0.05±0.02 mg-l was within the limits during the wet season but during the dry season, the value 0.14±0.09mg-l exceeds the limits. Cd has a value of 0.06±0.01 in the wet season and 0.17±0.12 in the dry season, Cr has 0.36±0.12 in the wet season and 0.04±0.07 in the dry season, and Mn also has values of 0.46±0.12 and 0.22±0.03 in the wet and dry seasons respectively. Hence there was no significant difference (P>0.05) in the mean values of the sampling stations of the heavy metals during the wet and dry seasons. The study showed that the pond water was polluted with some heavy metals and hence measures must be taken to ensure the safety of the aquatic ecosystem, humans and the environment.

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