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Research Article
Evaluation of the Contamination Profile of Oysters from Soumbedioune/Dakar/Senegal Beach by PCB-DL
Diouf Sitor
,
Dione Mame Mor,
Diagne Ibrahima,
Ndiaye Birame*,
Dione Cheikh Tidiane,
Hane Maoudo,
Ba Seydou,
Cisse Dame,
Ka Ousmane,
Sarr Mamadou,
Diebakate Cheikhna,
Ndiaye Momar
Issue:
Volume 11, Issue 4, December 2025
Pages:
113-121
Received:
5 September 2024
Accepted:
23 September 2024
Published:
17 October 2025
Abstract: Contamination of the marine environment by persistent organic pollutants (POPs) is a worrying issue. So-called "dioxin-like" PCBs in particular are pollutants that are widely dispersed in the environment. Furthermore, due to their affinity with fatty tissues, they are highly bioaccumulated by aquatic species. In return, these organisms consumed by humans as food can be a source of contamination. Hence the interest in studying these biological matrices in order to become aware of the risks of degradation of aquatic ecosystems. In this work, the contamination profile of oysters from Soumbedioune beach by DL-PCBs (PCB81; 114; 118; 123; 126; 167; 169; 189) was studied. The analysis method used is Gas Chromatography Coupled with Mass Spectrometry (GC-MS). The average levels of the different campaigns of July, August and September 2021 are respectively 28.218; 119.863; 48.053 µg/Kg in dry weight in oysters. These levels are above the maximum limit according to European Commission Regulation No. 1881/2006 (0.008 µg/Kg). Thus we estimated the exposure of the population to PCB-DL. The factor obtained varies from 0.005 µg/Kg to 0.28 µg/Kg for an individual of 40 Kg and from 0.002 µg/Kg to 0.17 µg/Kg for an individual of 70 Kg. In 2002, the WHO proposed a tolerable daily dose of 0.02 µg/kg/body weight per day for all PCBs. According to these results, the contamination status of Soumbedioune beach is worrying and the consumption of these oysters as food could prove problematic for health. Consequently, a synergy involving the stakeholders, namely the populations, industrialists, authorities and the scientific community, could lead to better solutions. To do this, it is necessary to treat the effluents that are discharged into this coastline and to raise awareness among the populations of the consequences of the contamination of the marine environment.
Abstract: Contamination of the marine environment by persistent organic pollutants (POPs) is a worrying issue. So-called "dioxin-like" PCBs in particular are pollutants that are widely dispersed in the environment. Furthermore, due to their affinity with fatty tissues, they are highly bioaccumulated by aquatic species. In return, these organisms consumed by ...
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Research Article
Application of the QUAL2K Water Quality Model to Assess Pollutant Dispersion in River Sosiani in Western Kenya
Maemba Okori*,
Julius Kipkemboi Kollongei
Issue:
Volume 11, Issue 4, December 2025
Pages:
122-129
Received:
16 August 2025
Accepted:
1 September 2025
Published:
27 October 2025
Abstract: This study applied the QUAL2K water quality model to investigate the pollutant dispersion dynamics in River Sosiani, a vital freshwater source in western Kenya. The river, which historically supported diverse domestic, agricultural and recreational uses for the Eldoret City residents, is currently facing severe degradation due to urbanization and inadequate waste management practices. The model was calibrated and validated using weekly field data collected over six months from designated sampling points. Model performance was evaluated using standard statistical measures, including the R-Squared correlation (R2), the Nash-Sutcliffe efficiency (NSE), and the ratio of the Root Mean Square Error to the observations’ standard deviation (RSR). The results demonstrated good to excellent performance, with R2 values ranging from 0.82 to 0.95, NSE value above 0.75, and RSR values below 0.5 confirming the model’s reliability in simulating the rivers pollutant dispersion dynamics. The simulation results revealed deterioration in water quality from upstream to downstream. Precisely, dissolved oxygen (DO) decreased significantly along the river course, while carbonaceous biochemical oxygen demand (CBODf), electrical conductivity (EC), temperature, total phosphate (TP), and nitrate-nitrogen (NO3-N) concentration all increased. pH remained within the neutral to slightly alkaline range, with some localized shifts downstream, while flow discharge (DS) increased progressively from upstream to downstream. These trends, revealing an increasing pollution load, mainly in urbanized areas, highlight the significant impact of anthropogenic activities on River Sosiani ecological health and underline the urgent need for targeted interventions to mitigate further degradation.
Abstract: This study applied the QUAL2K water quality model to investigate the pollutant dispersion dynamics in River Sosiani, a vital freshwater source in western Kenya. The river, which historically supported diverse domestic, agricultural and recreational uses for the Eldoret City residents, is currently facing severe degradation due to urbanization and i...
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Case Report
Case Analysis of Wastewater Treatment Project for Citrus (Citrus aurantium L.) Extract Production
Issue:
Volume 11, Issue 4, December 2025
Pages:
130-137
Received:
10 November 2025
Accepted:
24 November 2025
Published:
17 December 2025
DOI:
10.11648/j.ajwse.20251104.13
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Abstract: The extract of citrus (Citrus aurantium L.) plays a significant role in medical and pharmaceutical applications due to its rich content of hesperidin, methyl hesperidin, and other compounds. However, wastewater generated from citrus extraction contains substances such as pectin, which readily encapsulate biochemical strains and inhibit their activity. This severely impairs the function of biochemical degradation processes, posing significant challenges in wastewater treatment. This project employs a “dissolved air flotation + iron-carbon fluidized bed” pretreatment process to remove pectin and enhance wastewater biodegradability, followed by a combined “upflow anaerobic sludge blanket (UASB) + anoxic-oxic (A/O)” biochemical unit to eliminate organic pollutants. Operational results indicated that the influent water quality for the project ranged from pH 4.5 to 6.5, with chemical oxygen demand (CODcr) ≤ 9800 mg/L, ammonia nitrogen ≤ 40 mg/L, suspended solids (SS) ≤ 2000 mg/L. The pretreatment process achieved a pectin removal rate exceeding 87%, significantly enhanced biodegradability, and stabilized the biochemical oxygen demand (BOD)/CODcr ratio at approximately 0.4. The final effluent quality achieved a pH range of 6 to 9, CODcr ≤ 500 mg/L, ammonia nitrogen ≤ 25 mg/L, SS ≤ 400 mg/L, consistently meeting the discharge standards specified in the “Integrated Wastewater Discharge Standard” (GB 8978-1996) for pipe discharge. This combined process offers stable and reliable effluent quality with simple and efficient management. It holds significant reference value and promising application prospects for wastewater treatment in industries such as plant extraction and fruit processing.
Abstract: The extract of citrus (Citrus aurantium L.) plays a significant role in medical and pharmaceutical applications due to its rich content of hesperidin, methyl hesperidin, and other compounds. However, wastewater generated from citrus extraction contains substances such as pectin, which readily encapsulate biochemical strains and inhibit their activi...
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