Eastern Niger Research Articles

Magnetic Structure of Agadem Petroleum Block (Termit Basin, Eastern Niger): Analysis and Interpretation of Aeromagnetic Data

The Agadem block is an area of major oil interest located in the large sedimentary basin of Termit, in the south-east of the Republic of Niger. Since the 1950s, this basin has known geological and geophysical research activities. However, despite the extensive research carried out, we believe that a geophysical contribution in terms of magnetic properties and their repercussions on the structure of the Agadem block allowing the improvement of existing knowledge is essential. The present study aims to study the structural characteristics of the Agadem block associated with magnetic anomalies. For this, after data shaping, several filtering techniques were applied to the aeromagnetic data to identify and map deep geological structures. The reduction to the pole map shows large negative wavelength anomalies in the southeast half of the block and short positive wavelength anomalies in the northwest part embedded in a large positive anomaly occupying the lower northern half of the block. The maps of the total horizontal derivative and tilt angle show lineaments globally distributed along the NW-SE direction in accordance with the structural style of the study area. The resulting map highlights numerous lineaments that may be associated with faults hidden by the sedimentary cover. The calculation of the Euler deconvolution allowed us to locate and estimate the depths of magnetic sources at variable depths of up to 4000 m. The compilation of the results obtained allowed us to locate zones of high and low intensities which correspond respectively to horsts and grabens as major structures of the Agadem block.

Development and Application of Human Health Risk-Based Screening Levels for Crude Oil Affected Soils and Sediments in the Niger Delta.

Management of oil impacted sites in Nigeria is regulated through the Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN). This includes an intervention value for total petroleum hydrocarbons (TPH) of 5,000 mg/kg as a trigger for remedial action. This single intervention value does not differentiate between varied land uses or the specific chemical composition of spilled oil. The EGASPIN does allow development of refined screening levels based upon human health risk assessment methods. Following these requirements, we have applied the ASTM risk-based corrective action (RBCA) process to define Tier 1 Risk Based Screening Levels (RBSLs) and Tier 2 Site Specific Target Level (SSTLs). Both are derived using United States Environmental Protection Agency (USEPA) guidance supplemented by equations correcting for the properties of chemical mixtures, presence of a residual oil phase, and preferential depletion of volatile oil components. The RBSLs were calculated for five Nigerian crude oils and six exposure scenarios specific to the Niger Delta while SSTLs were calculated using sediment sampling results and four exposure scenarios from the Bodo oil spill area located in the eastern Niger Delta mangrove swamp area. Derived TPH RBSLs range between a factor of 2.5 lower (more stringent) for residential land use to > 10x higher for 'Commercial and Industrial Workers', when compared to the Nigerian EGASPIN intervention value. Derived SSTLs for TPH ranged between a value just above the intervention value for shoreline areas near Bodo Town to values ∼6x higher than the intervention value for most uninhabited mangrove areas. The derived RBSLs and SSTLs are protective of human health but other criteria (aesthetic, ecological) may be more stringent. Additional criteria are introduced, including oil mobility (potential spreading of existing impacts) and criteria for ensuring the viability of the mangrove environment.

BEARING CAPACITY AND FOUNDATION QUALITY OF SUBSOILS IN PARTS OF THE MAIN CAMPUS OF AKWA IBOM STATE UNIVERSITY, IKOT AKPADEN, AKWA IBOM STATE, NIGERIA

The study of the Foundation quality of Subsoils in parts of the main campus of Akwa Ibom State University, Ikot Akpaden, Eastern Niger Delta, Nigeria was carried out with the aim of determining the bearing capacity of the subsoils and designing suitable foundations for the construction of structures. Through field and laboratory investigations carried out, the geophysical study revealed four geo-electric layers namely; the top soil, silty clay, sand, and clayey sand. Six geotechnical boreholes were drilled in the field to a maximum depth of 15m each, with standard penetration tests and cone penetration tests carried out. Soil samples were extracted at 1meters each for different laboratory tests including; moisture content, liquid limit, plastic limit, bulk density, specific gravity, particle size distribution, shear box test, undrained shear strength and Consolidation test. The subsurface stratigraphic profile consists of clayey silty sand (0-7m), sandy silty clay (2-14m) and sand (10-15m) from top to bottom. The clayey silty sand are soft to firm, low to medium compressibility clays with liquid limit, plastic limit and average cohesion values of 23% to 41.5%, 14% to 24% and 14KN/m2 to 64KN/m2 respectively. Ultimate bearing capacity values of the clayey silty sand range from 152.65KN/m2 to 667.94KN/m2. The sandy silty clays are soft, intermediate to high compressibility clays with liquid limit, plastic limit and average cohesion values of 44% to 83%, 25.5% to 51% and 10KN/m2 to 32KN/m2 respectively. Ultimate bearing capacity values of the sandy silty clay range from 269.43KN/m2 to 582.4KN/m2.The sand is poorly graded, medium dense with standard penetration N- values ranging from 13-16. The ultimate bearing capacity ranges from 7878.12KN/m2 to 11423.36KN/m2 respectively. Standard penetration tests and pile bearing capacity analysis indicate that the sands are suitable foundation materials for construction. A Pile foundation terminated within the sand substratum is recommended for large structures.

A review of the Eastern Niger Rifts tectonostratigraphy and petroleum systems

A review of the Eastern Niger Rifts tectonostratigraphy and petroleum systems

Sedimentation rates, coastal delta accretion, and stratigraphic datum of the Late Pleistocene–Mid-Holocene transition in the East Equatorial Atlantic: New concept from calcareous nannoplankton

This study examines the sedimentation rates (SR) during the last 20 kyr in the Niger Delta using selected biostratigraphic datum levels. Three gravity cores (GCs) collected at −40 m below sea level from the shallow offshore Niger Delta (GC1 = Western, GC2 = Central, and GC3 = Eastern) were analysed for their calcareous nannoplankton species ( Emiliania huxleyi , Gephyrocapsa oceanica , Helicophaera sellii and Reticulofenestra asanoi ). Successive datums were established mainly from the informal biozones and ranges of Gephyrocapsa oceanica and Emiliania huxleyi marker species due to their abundance. By correlating the First Occurrence (FOC) and Last Occurrence (LOC) datums of the marker species in the cored sequences (GCs), SRs were reconstructed. Based on the constructions, the FOC of Gephyrocapsa oceanica (20 kyr) reflects a position towards the bottom of the GCs, the FOC of Emiliania huxleyi (11–8.5 kyr) delineates the middle of the GCs, and the LOC of Emiliania huxleyi (6.5 kyr) marks the uppermost part of the GCs. The sediment load by average calculated from each location in the Western, Central, and Eastern Niger Delta shows sequences of sedimentation rates of ~36.7 cm/kyr for the late Pleistocene, ~174 cm/kyr for the early Holocene, and ~18.6 cm/kyr for mid-Holocene time periods. Consequently, on average, ~229.3 cm/kyr of sediment were deposited at −40 m water level over the last 20 kyr, with the early Holocene experiencing the highest sedimentation rates (~174 cm/kyr) across the three locations. Additionally, this study provides evidence that the Niger Delta sink deposits responded to the West African Monsoon (WAM) driven sedimentation rates during the late Quaternary (20–6.5 kyr). Furthermore, this sediment deposit facilitated the development of a high-resolution age-depth and sedimentation rate model linked to the regional sea level of the Eastern Equatorial Atlantic that succinctly delineates the late Pleistocene and early Holocene boundary of the Niger Delta. The outputs of this study bridged the research gap and knowledge on the impact of coastal accretion and depositional processes on sedimentation rates in the shallow offshore Niger Delta.

Correction: Basin margin sediment wedge build out of the Eastern Niger Delta: application of shelf-edge trajectory pattern studies

The articles of issues 11(3) and 11(4) were published with incorrect abbreviated

Source, transport, and fate of nitrate in shallow groundwater in the eastern Niger Delta

The eastern Niger Delta region in Nigeria is a hotspot for reactive nitrogen pollution due to extensive animal husbandry, pit latrine usage, and agricultural practices. Despite the high level of human activity, the sources and processes affecting nitrogen in groundwater remain understudied. Groundwater nitrate (NO3−) concentrations are highly variable, with some areas recording values well above the safe drinking water threshold of 50 mg/L. This is particularly true near municipal sewage systems. Elevated nitrite (NO2−) and ammonium (NH4+) concentrations were also detected in the study area. Sewage analysis revealed NO3− concentrations ranging from 1 to 145 mg/L, NO2− from 0.2 to 2 mg/L, and notably high NH4+ concentrations. A comparison of major ions indicated that 71%, 90%, 87%, and 92% of groundwater samples surpassed reference site levels for calcium (Ca2+), sodium (Na+), potassium (K+), and chloride (Cl−), respectively, pointing to sewage as a likely source of contamination. The NO3−/Cl− ratios at several sites suggested that most groundwater NO3− originates from human waste. Stable isotope analysis of NO3− showed a general enrichment in 15N and, in some cases, a depletion in 18O, indicating that the NO3− originates from sewage-derived NH4+ nitrification. Although denitrification, a process that reduces NO3−, is present, the high dissolved oxygen (DO) and NO3− levels in the groundwater suggest that denitrification is insufficient to fully mitigate NO3− pollution. Consequently, there is a risk of NO3− leaching from shallow aquifers into the Niger Delta’s surface waters and ultimately into the coastal ocean.

Characterization of a deep-water turbiditic reservoir under an active hydrodynamic regime (Niger delta)

Characterization of a deep-water turbiditic reservoir under an active hydrodynamic regime (Niger delta)

Pipeline-Related Residential Benzene Exposure and Groundwater Natural Attenuation Capacity in the Eastern Niger Delta, Nigeria

This study was conducted to investigate the presence of benzene in the ground and drinking water in the eastern Niger Delta, where multiple oil and gas production facilities are present. Samples from drinking water wells were collected for measurements of benzene, toluene, ethylbenzene, and xylenes (BTEX). Additionally, the dissolved organic carbon (DOC) concentration was determined for the first time to establish the groundwater’s total hydrocarbon and non-hydrocarbon load. The groundwater BTEX and benzene levels were up to 3904 µg/L and 3500 µg/L, respectively. DOC concentrations were up to 49 mg/L. The highest benzene concentrations were detected in wells near an underground petroleum pipeline. However, the concentrations decreased with distance from the pipeline to levels less than 0.1 µg/L. Despite benzene contamination, the aquifer has shown promising aerobic attenuation potential, having up to a 7.5 (95%) mg/L DO level and 2.11 mg/L BTEX biodegradation capacity for DO. However, the high groundwater temperature of up to 32.5 °C may weaken attenuation. The benzene and BTEX point attenuation rates ranged from 0.128 to 0.693 day−1 and 0.086 to 0.556 day−1, respectively. Hence, by natural attenuation alone, up to 66.5 and 85 years would be required to reach Nigeria’s groundwater benzene and BTEX remediation goals, respectively.

Vulnerability of Coastal Livelihood to Sea Level Rise and Climate Change in Eastern Niger Region of Nigeria

Studies were carried out to assess the vulnerability of Coastal livelihood to sea level rise and effect of climate change in Eastern Niger Region of Nigeria. The study area covered the major estuaries in the south-eastern Nigeria. questionnaires, Focus Group Discussions were used in the study on the basis of finding, The primary occupation of households surveyed is fishing (64%), followed by forestry (mangrove resource) (26%) and daily wage laborer (10%); with significant difference of 0.310 (2-sided), livelihood ratio of 0.292 and linear by linear association of 0.740 at (0.05) significant level. It was observed that more income was spent on maintaining fishing gear, purchasing gasoline and health care with significant difference of p-value 0.002 (2-sided), livelihood ratio of 0.002 and linear by linear association of 0.008, as such the effect of flood on fish production in south-eastern Nigeria was on the increasing (80% at risk). The study concluded that, flooding is currently a major threat to the fishermen’s livelihoods especially the resultant decline in mangrove abundance and diversity causing a reduction in fish production/catch. As such, a well-planned and managed mangrove reforestation programme is necessary, educating communities about the impacts of climate change and involving them in adaptation planning is essential for building resilience. Programs that raise awareness about sustainable practices and disaster preparedness can help mitigate climate risks also, establishing and managing protected areas such as marine parks and wildlife sanctuaries help conserve critical habitats and biodiversity to serve as hot spot to affected areas. It is also recommended that further research be carried out to investigate the physiological response of mangrove related to temperature and salinity.

Spatial distribution and human health risk assessment of heavy metals in groundwater of Kolo- Creek and Environs, Eastern Niger Delta, Nigeria

This study investigated the distribution of heavy metals and human health risk assessment of them in the groundwater of Kolo Creek and environs, Niger Delta, Nigeria. Groundwater samples were collected from ten geo-referenced borehole points drilled to depths of 6 m. An Atomic Absorption Spectrophotometer (AAS) was utilised to ascertain the pollutant concentrations in the conserved samples. The average mean concentrations of the heavy metals (Cu = 0.43 mg/l, Zn =0.97 mg/l), (Cr, Cd, Hg, and Al not detected) in this study area for the two seasons were below international recommended limits except Pb = 0.019 mg/l and Fe = 35.57 mg/l which are above the international recommended limits of 0.01 mg/l and 0.3 mg/l respectively. The HI average (non-carcinogenic risk) value (1.561) for adults in all the locations is greater than 1, suggestive of likely health problems. The average HI value for children in all the locations is also greater than 1 (3.698), three times the value of adults also suggestive of greater health problems due to presence of the metallic contaminants in the children compared to the adults. The average CR (carcinogenic risk) value for Pb in adults and children in all locations exceeded (> 10−6) suggesting the possibility of cancer risk due to the intake of contaminated groundwater. Therefore, the results show that the children are at greater risk of cancer threefold more than the adults.

Gravity tectonics controls on reservoir-scale sandbodies: Insights from 3D seismic geomorphology of the canyons buried in the upper slope of the Eastern Niger delta basin

Gravity tectonics controls on reservoir-scale sandbodies: Insights from 3D seismic geomorphology of the canyons buried in the upper slope of the Eastern Niger delta basin

Machine learning methods of satellite image analysis for mapping geologic landforms in Niger: A comparison of the Aïr mountains, Niger River basin and Djado Plateau

This study analyses geological landforms and land cover types of Niger using spaceborne data. A landlocked African country rich in geological structures, Niger is notable for contrasting environmental regions which were examined and compared: 1) lowlands (Niger River basin); 2) Aïr Mountains; and 3) Djado Plateau. The methodology is based on machine learning (ML) models and programming applied for Earth observation data. Spatio-temporal analysis was performed using Landsat 8-9 OLI-TIRS multispectral images classified by GRASS GIS. Data were processed by scripts using ML algorithms by modules r.random, r.learn.train, r.learn.predict, i.cluster, and i.maxlik. The algorithms of probabilistic forecasting included support vector machine (SVM), random forest (RF), decision tree classifier and K neighbors classifier. Variations in landscapes caused by water deficit and soil erosion were analyzed, and parallels between geologic and environmental setting were drawn. The intra-landscape variability of patches within Niger is revealed from 2014 to 2024. Landscape patterns are affected by drought periods in central Niger, geological setting of mountains, distribution of crust Karst pits and sinkholes in Eastern Niger. Western region of the Niger River basin shown land cover patterns linked to hydrological effects of soil erosion. This paper shows the use of ML methods for geological-environmental analysis.

Integration of Petrophysical and 3D Seismic Attribute Analyses for Reservoir Characterization in Agana Field, Onshore Niger Delta, Nigeria

The study integrates petrophysical analysis, attribute studies of 3D seismic data to analyze structures, delineate reservoirs, identify prospects and estimate reserves within the Agana field. The study area is located in the coastal swamp of the Eastern Niger Delta. Four wells were used for the study. Four reservoirs A, B, C and D were identified and correlated across the wells. Volume attribute studies revealed a complexly faulted region. A total of sixty six faults were mapped and were labeled F1 to F66. The major faults were trending East-West direction, while the minor faults were trending in Northeast-Southwest direction. The trapping mechanism identified from the interpretation indicates that the field is characterized mostly by fault assisted closures. The results of the three surface attributes; RMS Amplitude, Extract value, Sum of Positive Amplitudes extracted from the subsurface structure maps identified only one prospect, B1 on horizon B. The average petrophysical parameters of reservoir B in the four wells which included thickness, net-to-gross, volume of shale, water saturation, hydrocarbon saturation and porosity, were calculated as 485.99ft, 0.58, 0.20, 0.52, 0.48, and 0.21, respectively. These average parameters were used to estimate the reserve for the identified prospect B1. The calculated results for Hydrocarbon Initially In Place (HIIP) and Hydrocarbon Pore Volume (HPV), are 303,709.43×106 STB, and 455,564.15ft3 respectively. Risk analysis based on Geologic Chance of Success showed that the prospect can be explored with 56% chance of success. The result showed integration of petrophysical and structural analysis with attribute studies to be more efficient in identifying prospect so that where structural interpretation is inefficient attribute studies compliment.

Lithostratigraphy and Sedimentation Models of TMG-C4 Well Offshore Eastern Niger Delta

Analysis was carried out in TMG-C4 well by integrating well logs data that revealed three depositional sequences within the Agbada Formation of about 400ft thick. Three systems tracts identified include highstand systems tract, transgressive systems tract and lowstand systems tracts. The highstand systems tract is majorly stacked regressive shoreface sands that occurred in two parasequence sets, whereas the transgressive systems tract is a transgressive unit with both source rock and sealing potentials. The lowstand systems tract shows a boxcar log motif and is identified to be probably channel or barrier bar sand. Major shale units (maximum flooding surfaces) with regional significance mapped are designated MFS. This division is relevant to identifying genetic depositional units. Three genetic sequences occurred in the well. The transgressive shales represent interruptions in the overall regressive sequence that is related to sea-level rise. Three of these shales have been mapped and two of them correspond to the eleven genetic megasequences that occur delta wide. A predominantly marine and deltaic sequences strongly influenced by clastic output from the continent is inferred from the well logs. Paleo water depth is interpreted to fluctuate considerably and deposition occurred within a variety of littoral and neritic environments ranging from nearshore barrier sand complexes to fully marine outer shelf mudstones. The sediments are rapidly deposited within the shallow marine realm and reworked into longitudinal bars by wave action, strong longshore drift and tidal effects. The dominant depositional trend observed in the well shows progradation

Sorption studies of Tetraoxophosphate (v) ions on some agricultural soils in Akwa Ibom State, eastern Niger Delta, Nigeria

The phosphate sorption capacity regulates principally the phosphorus concentration and available phosphorus in any soil solution. This work aims to study the phosphate sorption characteristics of five agricultural soils in Akwa Ibom State, Nigeria. The phosphate adsorption isotherm was obtained by shaking each soil sample with 20, 40, 60, 80, 100 and 120 mgL–1 for 24 h with 20 mL of KH2PO4 in 0.01 M CaCl2 solution. The Langmuir, Freundlich, Van Huay and Temkin isotherms were applied to study the PO43-sorption characteristics of the soil samples. The Freundlich model provided the best choice for phosphate sorption with mean R2 value of 0.9872. Results obtained for the phosphate sorbed (µg g–1soil) with 120 mgL-1 solution, heterogeneity factor of adsorption sites (nF), and the Freundlich constant (KF) (Lg–1) were 101(84.3), 0.515 and 7.355 for Onna soil; 62.8(52.3), 0.641 and 2.464 for Ikot-Amama 2; 60.6(50.5), 0.708 and 3.985 for Ogu-Itumbonuso soil; 59.3(49.5), 0.652 and 2.505 for Ikot-Amama 1 soils; 58.0(48.3), 0.704 and 3.682 for Ikot-Nkon soils, respectively. The equilibrium concentration for phosphates (EC-P) were used as desorption index to determine whether the soils could serve as potential sources for their bioavailability to plants and results ranged from 5.0 to 9.90 mgL–1, indicating high vulnerability to phosphate loss. The relationship between phosphate sorption parameters and soil physicochemical properties showed that the Freundlich adsorption intensity factor, nF, strongly correlated negatively with organic carbon and organic matter (r = -0.953 and -0.947; P<0.01), Fe and Mn (r = -0.911 and -0.812, P<0.05). The EC-P correlated strongly with soil pH(H2O) (r = 0.959, P<0.01), clay (r = 0.913, P<0.05), cation exchange capacity (CEC) (r = -0.824, P<0.05), Mn (r = -0.792, P<0.05) and Fe (r = -0.826, P<0.05). The study illustrated that soil management practices which involves the using organic fertilizers as the basis for PO43- sorption in relation to soil properties can be a useful tool for sustainable crop production and environmental soil-water contamination.

Impact of Climate Change on Fisheries Resources in the Eastern Niger Delta Regions, Nigeria

Studies were carried out during February – August 2022 to investigate the impact of climate change on fisheries resources in Eastern Niger Region of Nigeria. The study area covered was Cross River and Mbo River estuaries. Both face to face, group interview and structured questionnaire were used in the study, likewise the historic data on the annual climatic parameters of temperature, rainfall, comparative moistness and wind speed in the study area were obtained for the region, spanning over a period of 50 years and compared with more recent (10 years ago) for all the climatic factors. Results showed that 44.9% of the respondents indicate that climate change impacted on their fishing infrastructure in the area through damage to boat/canoe, anchor/net and drying hut, damage to fish dying hut, damage to fish processing platforms and damage to fish preservation cages/baskets. Revealing consistent fluctuations in the area for the past 50 years with the following mean temperature values of 26.92°C in the year 1986, 26.47°C in the year 2012 and 27.12°C in the year 2020 respectively. The statistical results reflect that the impacts on fisheries are not alarming and are controllable. On the basis of finding it was concluded that, the climate of Cross River Estuaries fluctuates with its attendant impact on artisanal fisheries in the area. The study noted important correlation among changing climatic apparatus and ecological problems of fisheries in the area.

Slope Stability Analysis of the Afaha Ekpenedi Integrated Farm Site, Esit Eket, Eastern Niger Delta, Nigeria

Slope Stability Analysis of the Afaha Ekpenedi Integrated Farm Site, Esit Eket, Eastern Niger Delta, Nigeria

The SEDIMENTOLOGICAL ANALYSIS, DEPOSITIONAL ENVIRONMENT AND SEQUENCE STRATIGRAPHIC STUDY OF IDA 4, 5, 6 WELLS NIGER DELTA BASIN, NIGERIA

Sequence stratigraphic study divides sedimentary successions into unconformity or maximum flooding surface bounded units (sequence) that form during a single, major cycle of sea-level change. Detailed sedimentological and sequence stratigraphic studies of the strata penetrated by Ida-4, 5, and 6 wells were carried out to deduce the depositional environment and correlate the stratigraphic units. The wells are located in the coastal swamp depobelt of the Eastern Niger Delta. Studied samples were dry-sieved for sedimentological analyses. Each fraction was studied under reflected light microscope. The lithology consists of an alternation of shale and sandstone units. The grain size of the sandstone units consists of fine to medium grains, occasionally coarse to granule-sized grains. Dominant accessories minerals are ferruginous materials, shell fragments, carbonaceous detritus, and few records, of mica flakes, glauconite, and pyrite. Regular sand and shale intercalation pattern on the Gamma Ray log permitted easy recognition of sub-cycles (autocycles) of sedimentation in an extensively developed paralic sequence. Paleoenvironmental reconstruction using accessories minerals recognizes shallow water settings with intermittent deeper water conditions. Rapid sedimentation rates are inferred in the studied area based on the observed alternation of thick sandstone, shale, and mudstone units. The MFS and SB were dated 9.5 Ma and 10.35 Ma respectively. Lithologic and system tracts correlations show lateral continuity of sandstone units (potential reservoirs) depicted in the lithofacies subcycles correlation. This is useful in the determination of reservoir geometry, areal coverage, and calculation of the volume of accumulated hydrocarbon, and directing well trajectory during the drilling operation.

Seasonal and Tidal variations of DO, BOD, and Nutrients in Major Rivers within Eastern Niger Delta, Nigeria

River channels within the Oil producing Area of Nigeria are highly impacted by the activities of the Oil Companies. This work examined the Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Nitrate (NO3-), Phosphate (PO43-), and sulphate (SO42-) in Calabar, Cross River, Imo, Great Kwa, and Qua-Iboe Rivers using standard procedures. Results showed that, DO, BOD, NO3-, and SO42- were within their limits by NESREA whereas, PO43- was higher than the limit. Mean levels of NO3-, PO43-, and SO42- were higher during the dry season and low tidal regime while DO and BOD showed higher levels in wet season and high tidal regime. Results also indicated that, DO belong to the slightly polluted class, BOD, NO3-, and SO42- belong to the non-polluted class whereas, PO43- varied between moderately polluted and the severely polluted classes in the studied aquatic channels. Generally, the relationships among the parameters varied from one parameter to the other. Principal component analysis (PCA) identified mainly the anthropogenic factor and moderately the natural factor as being responsible for the levels of the parameters assessed in the studied rivers. Hierarchical clusters analysis (HCA) recorded common associations and sources for the DO and BOD, PO43- and SO42- while NO3- had a separate and personal cluster. The study revealed the existing relationships among the studied parameters and their related impact on the health of the aquatic ecosystems investigated.