scholarly journals Impacts of Emerging Agricultural Practices on Groundwater Quality in Kahe Catchment, Tanzania

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2263 ◽  
Author(s):  
Lwimbo ◽  
Komakech ◽  
Muzuka
Keyword(s):  
Groundwater Quality ◽  
Large Scale ◽  
Agricultural Practices ◽  
Pesticides Residues ◽  
Average Value ◽  
Intensive Use ◽  
Shallow Wells ◽  
Dry Seasons ◽  
Deep Boreholes ◽  
Wet And Dry Seasons

This paper assesses the impacts of farmers’ intensive use of agrochemicals (fertilizers and pesticides) on groundwater quality in the Kahe catchment. Samples were collected during the wet and dry seasons of the year 2018 and analyzed for the presence of agrochemicals in the water. Groundwater chemistry was dominated by magnesium-sodium-bicarbonate (Mg-Na-HCO3−). The cations levels were in the trend of Mg2+ >Na+ > Ca2+ > K+, whereas anions were HCO3− > Cl− > SO42− for both seasons. The NO3− had an average value of about 18.40 ± 4.04 and 7.6 ± 1.7 mg/L in the wet and dry season, respectively. Elevated levels of nitrate, sulfate, phosphate, and ammonium were found in water samples collected near the large-scale sugarcane plantation in the catchment. For both seasons, Pb, Cd, Fe, Mn, Zn and Cu concentrations averaged approximately 0.08 ± 0.03, 0.11 ± 0.03, 0.16 ± 0.02, 0.11 ± 0.01, 0.46 ± 0.05, and 0.55 ± 0.02 mg/L, respectively. On the other hand, the concentrations were higher in shallow wells than in the deep boreholes. Pesticides’ residues were below the detection limit in all sampled groundwater. The findings from this study provide important information for intervention in groundwater quality management in Kahe Catchment, Tanzania.

Spatial distribution of Serengeti wildebeest in relation to resources

1999 ◽  
Vol 77 (8) ◽  
pp. 1223-1232 ◽  
Author(s):  
John F Wilmshurst ◽  
John M Fryxell ◽  
Brian P Farm ◽  
ARE Sinclair ◽  
Chris P Henschel
Keyword(s):  
Spatial Distribution ◽  
Energy Intake ◽  
Large Scale ◽  
Spatial Scales ◽  
Mechanistic Model ◽  
Large Herbivores ◽  
Serengeti Ecosystem ◽  
Dry Seasons ◽  
Behavioural Factors ◽  
Wet And Dry Seasons

We investigated the spatial distribution of radio-marked wildebeest (Connochaetes taurinus) in the Serengeti ecosystem in relation to the distribution of their food resources, comparing patterns in the wet and dry seasons and at local and landscape spatial scales. A mechanistic model of ruminant energy optimization predicted that wildebeest should maximize energy intake on swards 3 cm high and maintain energy balance on swards between 3 and 10 cm high. At the ecosystem scale, wildebeest preferred short and intermediate-height grass of moderate greenness during both the wet and dry seasons. This was consistent with the model prediction which suggests that large-scale movements by wildebeest are motivated, at least partially, by an energy-maximizing strategy. At the local scale, however, wildebeest showed spatial selectivity only on the basis of grass greenness, not on grass height. This differed from model expectations and may have resulted from wildebeest exploiting ephemeral green flushes of grass caused by localized rainfall in their movement radius. According to these results, the influence of other nutritional or behavioural factors on wildebeest distributions is not rejected, yet they suggest the potentially important role of an energy intake maximizing strategy on movement patterns. Our findings show that wildebeest movements are broadly similar to those of other large herbivores that migrate in response to resource gradients.

scholarly journals A BRIEF OBSERVATION OF THE FORMATION OF COHERENT STRUCTURES AND TURBULENCE OVER A RAIN FOREST AREA IN CENTRAL AMAZÔNIA: THE ATTO-CLAIRE/IOP – 1/2012 EXPERIMENT

2017 ◽  
Vol 35 (3) ◽  
Author(s):  
Newton Silva de Lima ◽  
Julio Tota da Silva ◽  
Maurício José Alves Bolzam ◽  
Alan Dos Santos Ferreira ◽  
Matheus Da Rocha Pietzsch
Keyword(s):  
Coherent Structures ◽  
Large Scale ◽  
Inflection Point ◽  
Terra Firme ◽  
Central Amazonia ◽  
Intensive Observation ◽  
Dry Seasons ◽  
Box Plot ◽  
Observation Period ◽  
Wet And Dry Seasons

ABSTRACT. This work used micrometeorological measurements of temperature and wind in order to characterize the turbulence due to wind in a terra firme forest in central Amazonia as part of the ATTO-CLAIRE / IOP-1 (2012) (Amazon Tall Tower Observatory – Cooperative LBA Airborne Regional Experiment / Intensive Observation Period – 2012 / LBA – Large Scale Biosphere-Atmosphere Experiment in the Amazon). This research was conducted at the Uatumã ATTO Sustainable Development Reserve in the State of Amazonas, Brazil, from February to September, 2012, and used data from February 26 to September 07, 2012, dates that partially encompass the wet and dry seasons, respectively. The ATTO site has 5 towers: one that is 320m, and four that are 80 m in height, and this research was conducted on an 80 m triangular tower. A total of ten 3D and 2D ultrasonic anemometers were installed on the tower, and the importance of these instruments used for flux measurements is also evident when taking into account the fact that the dissemination and diffusion of seeds and chemical composts in the forest happens through the action of turbulent fluxes. In order to understand the wind profile, the inflection point of the wind velocity, and coherent structures (ECs) and local turbulence, box-plot diagrams, quadrant analyses, wavelet potential spectrum, and energy potential analyses were conducted. The turbulence characterized at the ATTO had a roll or ramp structure during the study period, which represents favorable conditions for the maintenance of the forest during the wet and dry seasons in the Central Amazon. Keywords: inflection point, ramp, wavelet, turbulence. RESUMO. Este trabalho faz uso de medidas micrometeorológicas de temperatura e vento, com finalidade de caracterizar a turbulência aerotransportada em uma floresta de terra firme na Amazônia Central, realizadas no experimento ATTO-CLAIRE / IOP-1 (2012) (Amazon Tall Tower Observatory – Cooperative LBA Airborne Regional Experiment / Intensive Observation Period – 2012 / LBA – Large Scale Biosphere-Atmosphere Experiment in Amazônia), no sítio do ATTO, na Reserva de Desenvolvimento Sustentável do Uatumã – AM (Brasil) nos meses de fevereiro a setembro de 2012, com dados analisados a partir do dia 26 de fevereiro de 2012 até o dia 7 de setembro de 2012, entre as estações úmida e seca na Amazônia Central, no complexo de torres altas composta de 5 (cinco) torres; uma de 320 m e 4 (quatro) de 80 m. Este trabalho foi realizado na torre triangular (80 m). Foram instalados 10 (dez) anemômetros ultrassônicos de 3D e 2D. Equipamentos necessários em método de fluxos, visto que, a disseminação e difusão de sementes e compostos químicos da floresta, faz-se também por fluxos turbulentos. Para compreensão do perfil de vento, ponto de inflexão do perfil da velocidade do vento, estruturas coerentes e a turbulência local, para tal desenvolveu-se a partir dos dados processados, diagrama de caixa (box-plot ), análise de quadrantes, espectro de potência em ondeletas, espectro de energia. A turbulência caracterizada no ATTO, foi de estruturas do tipo “rolo” ou rampa, para o período estudado, condições favoráveis para manutenção da floresta em período úmido-seco na Amazônia Central.Palavras-chave: ponto de inflexão, rampa, ondeleta, turbulência.

scholarly journals Modelling spatio-temporal heterogeneities in groundwater quality in Ghana: a multivariate chemometric approach

2017 ◽  
Vol 15 (4) ◽  
pp. 658-672
Author(s):  
Frederick Ato Armah ◽  
Arnold Paintsil ◽  
David Oscar Yawson ◽  
Michael Osei Adu ◽  
Justice O. Odoi
Keyword(s):  
Groundwater Quality ◽  
Predictive Accuracy ◽  
Groundwater Resources ◽  
Quality Data ◽  
Anthropogenic Factors ◽  
Dry Seasons ◽  
Chemometric Approach ◽  
Spatio Temporal ◽  
Very High ◽  
Wet And Dry Seasons

Chemometric techniques were applied to evaluate the spatial and temporal heterogeneities in groundwater quality data for approximately 740 goldmining and agriculture-intensive locations in Ghana. The strongest linear and monotonic relationships occurred between Mn and Fe. Sixty-nine per cent of total variance in the dataset was explained by four variance factors: physicochemical properties, bacteriological quality, natural geologic attributes and anthropogenic factors (artisanal goldmining). There was evidence of significant differences in means of all trace metals and physicochemical parameters (p < 0.001) between goldmining and non-goldmining locations. Arsenic and turbidity produced very high value F's demonstrating that ‘physical properties and chalcophilic elements’ was the function that most discriminated between non-goldmining and goldmining locations. Variations in Escherichia coli and total coliforms were observed between the dry and wet seasons. The overall predictive accuracy of the discriminant function showed that non-goldmining locations were classified with slightly better accuracy (89%) than goldmining areas (69.6%). There were significant differences between the underlying distributions of Cd, Mn and Pb in the wet and dry seasons. This study emphasizes the practicality of chemometrics in the assessment and elucidation of complex water quality datasets to promote effective management of groundwater resources for sustaining human health.

scholarly journals Analysis of Pesticide Residues in Tomatoes and French Beans from Murang’a and Kiambu Counties, Kenya

2020 ◽  
pp. 121-132
Author(s):  
Evans Kipkemoi ◽  
Warren A. Andayi ◽  
Eric C. Njagi ◽  
Brian Ptoton
Keyword(s):  
Pesticide Residues ◽  
The European Union ◽  
Health And Environmental Effects ◽  
Pesticides Residues ◽  
French Beans ◽  
Food Standards ◽  
Maximum Residue Levels ◽  
Dry Seasons ◽  
Handling Practices ◽  
Wet And Dry Seasons

Poor Pesticide-handling practices during production of tomatoes and French beans pose adverse health and environmental effects. This study was conducted to determine the concentrations of pesticide residues in tomatoes and French beans grown and sold in Murang’a and Kiambu counties, Kenya. Samples were collected in farms and markets during the wet and dry seasons. Pesticide residues were extracted using the QuEChERS method and quantified using GC-MS/MS and LC-MS/MS. The recoveries of pesticides from spiked samples were within the acceptable range (70-120%) for quantitative pesticide residue methods. The concentration range of pesticides residues in tomatoes were: profenofos, <LOQ to 0.18 mg/Kg;   omethoate, <LOQ to 0.03 mg/Kg; indoxacarb, <LOQ to 0.05 mg/Kg; chlorantraniliprole <LOQ to 0.11 mg/Kg; spirotetramat <LOQ to 0.01 mg/Kg; and metalaxyl < LOQ to 0.02 mg/Kg. The concentration range of pesticides residues in French beans were: imidacloprid <LOQ to 0.29 mg/Kg; chlorantraniliprole <LOQ to 0.37 mg/Kg; spirotetramat <LOQ to 0.01 mg/Kg; indoxacarb <LOQ to 0.05 mg/Kg; and metalaxyl <LOQ to 0.02 mg/Kg. The concentrations of pesticide residues in tomatoes and French beans were below the Maximum Residue Levels set by the Joint FAO/WHO Food Standards Programme and the European Union except for concentrations of omethoate in tomatoes, which were higher in 29% of analyzed samples. The presence of omethoate in tomatoes, whose use in vegetables  is banned, suggests poor pesticide handling practices by some tomato farmers in the two  counties.

scholarly journals Tracking Sources and Fate of Groundwater Nitrate in Kisumu City and Kano Plains, Kenya

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 401 ◽  
Author(s):  
Benjamin Nyilitya ◽  
Stephen Mureithi ◽  
Pascal Boeckx
Keyword(s):  
Waste Water ◽  
Dry Season ◽  
Public Institutions ◽  
Kisumu City ◽  
Shallow Wells ◽  
Dry Seasons ◽  
Sanitation Systems ◽  
Groundwater Wells ◽  
Wet And Dry Seasons

Groundwater nitrate (NO3−) pollution sources and in situ attenuation were investigated in Kisumu city and Kano plains. Samples from 62 groundwater wells consisting of shallow wells (hand dug, depth <10 m) and boreholes (machine drilled, depth >15 m) were obtained during wet (May–July 2017) and dry (February 2018) seasons and analyzed for physicochemical and isotopic (δ15N-NO3−, δ18O-NO3−, and δ11B) parameters. Groundwater NO3− concentrations ranged from <0.04 to 90.6 mg L−1. Boreholes in Ahero town showed significantly higher NO3− (20.0–70.0 mg L−1) than boreholes in the Kano plains (<10.0 mg L−1). Shallow wells in Kisumu gave significantly higher NO3− (11.4–90.6 mg L−1) than those in the Kano plains (<10.0 mg L−1). About 63% of the boreholes and 75% of the shallow wells exceeded the drinking water WHO threshold for NO3− and NO2− (nitrite) during the study period. Mean δ15N-NO3− values of 14.8‰ ± 7.0‰ and 20.7‰ ± 11.1‰, and δ18O-NO3− values of 10.2‰ ± 5.2‰ and 13.2‰ ± 6.0‰ in wet and dry seasons, respectively, indicated manure and/or sewage as main sources of groundwater NO3−. However, a concurrent enrichment of δ15N and δ18O was observed, especially in the dry season, with a corresponding NO3− decrease, indicating in situ denitrification. In addition, partial nitrification of mostly sewage derived NH4+ appeared to be responsible for increased NO2− concentrations observed in the dry season. Specifically, targeted δ11B data indicated that sewage was the main source of groundwater NO3− pollution in shallow wells within Kisumu informal settlements, boreholes in Ahero, and public institutions in populated neighborhoods of Kano; while manure was the main source of NO3− in boreholes and shallow wells in the Kano and planned estates around Kisumu. Waste-water sanitation systems in the region should be urgently improved to avoid further deterioration of groundwater sources.

scholarly journals Cloud characteristics, thermodynamic controls and radiative impacts during the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) experiment

2017 ◽  
Vol 17 (23) ◽  
pp. 14519-14541 ◽  
Author(s):  
Scott E. Giangrande ◽  
Zhe Feng ◽  
Michael P. Jensen ◽  
Jennifer M. Comstock ◽  
Karen L. Johnson ◽  
...  
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Department Of Energy ◽  
Cloud Characteristics ◽  
Radiative Impacts ◽  
Atmospheric Radiation Measurement ◽  
Dry Seasons ◽  
Basin Region ◽  
Cloud Regimes ◽  
Wet And Dry Seasons

Abstract. Routine cloud, precipitation and thermodynamic observations collected by the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) and Aerial Facility (AAF) during the 2-year US Department of Energy (DOE) ARM Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign are summarized. These observations quantify the diurnal to large-scale thermodynamic regime controls on the clouds and precipitation over the undersampled, climatically important Amazon basin region. The extended ground deployment of cloud-profiling instrumentation enabled a unique look at multiple cloud regimes at high temporal and vertical resolution. This longer-term ground deployment, coupled with two short-term aircraft intensive observing periods, allowed new opportunities to better characterize cloud and thermodynamic observational constraints as well as cloud radiative impacts for modeling efforts within typical Amazon wet and dry seasons.

scholarly journals Cloud Characteristics, Thermodynamic Controls and Radiative Impacts During the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment

2017 ◽  
Author(s):  
Scott E. Giangrande ◽  
Zhe Feng ◽  
Michael P. Jensen ◽  
Jennifer Comstock ◽  
Karen L. Johnson ◽  
...  
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Short Term ◽  
Cloud Characteristics ◽  
Cloud Regime ◽  
Radiative Impacts ◽  
Dry Seasons ◽  
Thermodynamic Regime ◽  
Basin Region ◽  
Wet And Dry Seasons

Abstract. Routine cloud, precipitation and thermodynamic observations collected by the ARM Mobile Facility (AMF) and Aerial Facility (AAF) during the two-year DOE ARM Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign are summarized. These observations quantify the diurnal to large-scale thermodynamic regime controls on the clouds and precipitation over the undersampled, climatically important, Amazon basin region. The extended ground deployment of cloud-profiling instrumentation enabled a unique look at multiple cloud regime controls at high temporal and vertical resolution. This longer-term ground deployment coupled with two short-term aircraft intensive observing periods allowed new opportunities to better characterize cloud and thermodynamic observational constraints as well as cloud radiative impacts for modeling efforts within typical Amazon ‘wet’ and ‘dry’ seasons.

scholarly journals Investigating Groundwater Quality in the Flood Prone Neighborhood Area in Malaysia

2019 ◽  
Vol 51 (2) ◽  
pp. 123
Author(s):  
Nasir Nayan ◽  
Yazid Saleh ◽  
Mohmadisa Hashim ◽  
Hanifah Mahat ◽  
Koh Liew See
Keyword(s):  
Groundwater Quality ◽  
Water Samples ◽  
Dry Season ◽  
Wet Season ◽  
Alternative Source ◽  
Dry Seasons ◽  
Wet And Dry Seasons

The purpose of this study is to compare the quality of groundwater during wet and dry seasons in Malaysia especially in Kuala Krai District which frequently involved in annual monsoon floods and the question whether the wells can be used during floods as well as an alternative source when there are no floods. Six sampling stations were selected using six main parameters which included DO, pH, BOD, COD, TSS and NH3N. The assessment was conducted based on the standards set by Malaysian INWQS and the classification of WQI. The results of the analysis showed that most of the water samples taken during the wet season had concentration values that did not meet the DOE standards such as the DO, BOD, and NH3N parameters. Based on the WQI classification, majority stations during the wet season were in moderately contaminated except for station T6 which was clean. On the contrary, during a dry season were found to be clean except for station T1 which was moderately contaminated.

scholarly journals Pesticide Residue Levels in Soil, Water, Kales and Tomatoes in Ewaso Narok Wetland, Laikipia, County, Kenya

2019 ◽  
pp. 1-11
Author(s):  
Peter Ngolo ◽  
Mildred Nawiri ◽  
Alex Machocho ◽  
Helida Oyieke
Keyword(s):  
Soil Water ◽  
Pesticide Residues ◽  
Agricultural Practices ◽  
World Health ◽  
The European Union ◽  
Negative Effects ◽  
Wetland Biodiversity ◽  
Dry Seasons ◽  
Residue Levels ◽  
Wet And Dry Seasons

Soil, water, kales and tomatoes from Ewaso Narok wetland were collected during wet and dry seasons and analyzed for 15 pesticide residues. Multi-residues method (QuEChERS EN) was used for sample preparation and Liquid chromatography-tandem mass spectrometry (LC-MS/MS) used for analysis. The soil was highly contaminated compared to water, kales and tomatoes. Banned (Aldicarb, azinphos methyl) and restricted (diazinon, chlorpyrifos and fenpropathrin) pesticide residues were detected in sample matrices in different concentrations. Residues levels that exceeded the European Union (EU) maximum residues limit (MRLs) were found in kales (triadimefon, cyproconazole I and II, fenpropathrin), tomatoes (cyproconazole I and II, fenpropathrin and spiroxamine) and water (aldicarb). All the pesticide residues concentrations were within the recommended levels of the World Health Organization (WHO) and Agricultural Food Organization (FAO). Residue levels were significantly high in the upstream and midstream during wet and dry seasons. Temperatures, conductivity (EC), pH, salinity, total dissolved solids (TDS) and dissolved oxygen (DO) were measured to assess soil/water quality. All the physicochemical parameters were within the recommended levels. Though most residue levels were below the EU-MRLs, MCLs and within the toxicological levels (LD50), the negative effects of the long term exposure to the wetland biodiversity and human health are real and should not be ignored. Farmers need to embrace Good Agricultural Practices (GAP) in order to reduce over-reliance on pesticide use in the wetland.

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