Assessment of heavy metals pollution in sediment at the Omaruru River basin in Erongo region, Namibia

Onjefu, Sylvanus Ameh; Shaningwa, Fatima; Lusilao, Julien; Abah, J.; Hess, Euodia; Kwaambwa, Habauka M.

doi:10.1080/26395940.2020.1842251

Cited by 16 publications

(8 citation statements)

References 21 publications

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“…The observed variability in the study findings can be attributed to the textural properties identified, the degree and extent of the pollution sources, and the recorded water discharge at the sampling stations. The study findings, particularly the pH ranges, are slightly related to the pH values provided by Onjefu et al [86]. The average moisture content of the sediment samples ranged from 9.19 ± 0.3% to 41.46 ± 0.6%; the difference in the moisture content might be attributed to the textural properties of the sediment and other factors, such as the presence of total dissolved ions that reduce the saturation in the soil particles.…”

Section: Physical Parameterssupporting

confidence: 56%

Land-Use–Land Cover Changes in the Urban River’s Buffer Zone and Variability of Discharge, Water, and Sediment Quality—A Case of Urban Catchment of the Ngerengere River in Tanzania

Mbonaga,

Hamad,

Mkoma

2024

Hydrology

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The physical integrity of the Ngerengere River and its three tributaries drains within Morogoro Municipality were evaluated by assessing the variations in land-use–land cover (LULC) in the river’s buffer zone, the discharge, and the contamination of river water and sediment from nutrients and heavy metals. Integrated geospatial techniques were used to classify the LULC in the river’s buffer zone. In contrast, the velocity area method and monitoring data from the Wami-Ruvu Basin were used for the discharge measurements. Furthermore, atomic absorption spectrophotometry was used during the laboratory analysis to determine the level of nutrients and heavy metals in the water and river sediment across the 13 sampling locations. The LULC assessment in the river’s buffer during the sampling year of 2023 showed that bare land and built-up areas dominate the river’s buffer, with a coverage of 28% and 38% of the area distribution. The higher discharge across the sampling stations was in the upstream reaches at 3.73 m3/s and 2.36 m3/s at the confluences. The highest concentrations of heavy metals in the water for the dry and wet seasons were 0.09 ± 0.01, 0.25 ± 0.01, 0.03 ± 0.02, 0.73 ± 0.04, 4.07 ± 0.08, and 3.07 ± 0.04 mg/L, respectively, for Pb, Cr, Cd, Cu, Zn, and Ni. The order of magnitude of the heavy metal concentration in the sediments was Zn > Ni > Cr > Cu > Cd > Pb, while the highest NO2−, NO3−, NH3, and PO43− in the water and sediment were 2.05 ± 0.01, 0.394 ± 0.527 0.66 ± 0.05, and 0.63 ± 0.01 mg/L, and 2.64 ± 0.03, 0.63 ± 0.01, 2.36 ± 0.01, and 48.16 ± 0.01 mg/kg, respectively, across all sampling seasons. This study highlights the significant impact of urbanization on river integrity, revealing elevated levels of heavy metal contamination in both water and sediment, the variability of discharge, and alterations in the LULC in the rivers’ buffer. This study recommends the continuous monitoring of the river water quality and quantity of the urban rivers, and the overall land-use plans for conserving river ecosystems.

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Section: Physical Parameterssupporting

confidence: 56%

Land-Use–Land Cover Changes in the Urban River’s Buffer Zone and Variability of Discharge, Water, and Sediment Quality—A Case of Urban Catchment of the Ngerengere River in Tanzania

Mbonaga,

Hamad,

Mkoma

2024

Hydrology

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“…In Namibia, a semi-arid country, evaluation and monitoring of pollution of freshwater ecosystems are important to mitigate water shortage. This has been demonstrated by several local studies that aimed at assessing the levels of pollution due to heavy metals in marine environments (e.g [20]- [28]). However, the Orange river which extends from Lesotho through South Africa and Namibia into the Atlantic Ocean is poorly studied in Namibia, thus locally there exists limited literature on the status of metal pollution in this river.…”

Section: Introductionmentioning

confidence: 92%

“…The elucidation of the physicochemical parameters was based on the criteria of the World Health Organization (WHO). Multiple indices (CF, PLI, I geo and EF) classification used in [20] [39] as presented in Table 2, was adopted in this work to categorize pollution level, nature of enrichment and sediment quality.…”

Section: Metal Assessment In Sedimentsmentioning

confidence: 99%

A Pilot Study on the Concentration of Heavy Metals in Sediments from the Lower Orange River, //Karas Region, Namibia

Pitiya¹,

Jacob²,

Emilinot³

2022

MSCE

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Global water shortage is caused not just by the physical scarcity of water, but also by gradual deterioration of the quality of water resources such as lakes, streams and rivers with heavy metals. This present study evaluated the status of Mn, Fe, Cr, Cu, Ni, As, Zn, Pb and Cd in sediments from the lower Orange River by Inductively Coupled Plasma Atomic Emission Spectrometry technique by collecting a total of eleven samples, each weighing 1 -2 kg at the depth of 15 -20 cm from two observations sites along the lower Orange River and applying pollution indicators such as contamination factor(CF), pollution load index(PLI), index of geo-accumulation(I geo ) and enrichment factor(EF) to assay the nature and extent of heavy metals contamination in sediments. The sequence of the total heavy metal content in descending order was Fe > Mn > Cr > As > Zn > Ni > Cu > Pb > Cd. The results of CF and I geo showed Mn, Cd, Ni, Zn and Pb were minor sources of sediment contamination since most of the samples were unpolluted and moderately polluted by these metals. However, most sediments were moderate to considerably polluted with Cr, As and Fe suggesting that these were the major pollution sources. The value of PLI at one of the two observation sites was equivalent to the value of baseline level, while the next site indicted quality deterioration of the sediments. The EF revealed that Cr was moderately enriched and arsenic (As) significantly enriched in all the sediments, which suggested contamination due to anthropogenic intervention. Hence, it is recommended that sediment quality be evaluated on a regular basis to avoid further deterioration of the Orange River's health, which might have detrimental repercussions for both aquatic life and local communities along the river.

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“…The location of Oshikoto region (where anthill soil sample was collected) on the Namibian map (Source: Thomson, 2018). Open Journal of Soil Science potential (ORP) using a portable meter (HI9811-5, Hanna instrument) [21].…”

Section: ) Measurement Of Anthill Soil Physicochemical Parametersmentioning

confidence: 99%

Assessment of the Level of Metal(loid)s Pollution and Bioactive Compounds Screening of Anthill Soil

Kandanda,

Shafodino,

Ambuga

et al. 2023

OJSS

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The anthill soil is used by hypertensive elderly and teenagers from Oshikoto region (Namibia) and many of them testified stabilization of their blood pressure to normal after consuming the anthill soil-derived aqueous extracts. This study therefore investigated and/or assessed the physicochemical parameters, the contents of some metal(loid)s (and their associated potential health risks) and the qualitative composition of bioactive compounds of this anthill soil. The homogenous soil sample collected from various anthill soils in the Oshikoto region was used to obtain the measurements of physiochemical parameters. The elemental contents were determined (using an Inductively Coupled Plasma Optical Emission Spectrophotometer) after acid digestion in accordance with the EPA method 350B and their potential health risk assessments were performed. Methanol, aqueous methanol, and aqueous-based extracts were generated via maceration extraction process prior to the screening of bioactive compounds using standard diagnostic assays. The oxidation reduction potential (164.4 ± 16.6 mV) was the only physicochemical parameter whose value was within the World Health Organization limits for drinking water whereas, total dissolved solids (23 ± 5.5 mg/L), electrical conductivity (44 ± 10.1 uS/cm) and pH (5.35 ± 0.33) were out of specifications. Phenolic compounds, flavonoids, terpenoids, and cardiac glycosides were present in anthill soil (with respect to the extractants used) to which its antihypertensive properties can be attributed in addition to some of the studied mineral components. With respect to the pH, TDS and EC, and the contents of most metal(loid)s in relation to their health risk assessment values, the results suggest that aqueous extracts derived from this anthill soil can be deemed unsuitable for human consumption.

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Assessment of heavy metals pollution in sediment at the Omaruru River basin in Erongo region, Namibia

Cited by 16 publications

References 21 publications

Land-Use–Land Cover Changes in the Urban River’s Buffer Zone and Variability of Discharge, Water, and Sediment Quality—A Case of Urban Catchment of the Ngerengere River in Tanzania

Land-Use–Land Cover Changes in the Urban River’s Buffer Zone and Variability of Discharge, Water, and Sediment Quality—A Case of Urban Catchment of the Ngerengere River in Tanzania

A Pilot Study on the Concentration of Heavy Metals in Sediments from the Lower Orange River, //Karas Region, Namibia

Assessment of the Level of Metal(loid)s Pollution and Bioactive Compounds Screening of Anthill Soil

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