Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri

Jessica Carmelia Mbemba Peleka; Anthony Verdin; Mathilda Osiris Mahouekpo; Robert Faomowe Foko; Fatoumata Gueye; Fatoumata Bah; Aminata Toure; Mathilde Cabral; Mamadou Fall; Cheikh Diop

doi:doi:10.11648/j.ijee.20261101.12

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Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri

Jessica Carmelia Mbemba Peleka

, Anthony Verdin

, Mathilda Osiris Mahouekpo

, Robert Faomowe Foko

, Fatoumata Gueye, Fatoumata Bah

, Aminata Toure

, Mathilde Cabral

, Mamadou Fall

, Cheikh Diop^*

Published in International Journal of Ecotoxicology and Ecobiology (Volume 11, Issue 1)

Received: 3 March 2026 Accepted: 27 March 2026 Published: 16 April 2026

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Abstract

Bioavailable trace metals in sediments can be a significant source of contamination for aquatic organisms. The present study aims to evaluate the overall toxicity of the bioavailable fraction of Pb and Cd in sediments from the Senegalese coast on the bacterium Aliivibrio fischeri. Surface sediment samples were collected at five sites (Rufisque, Soumbedioune, Saint-Louis, Hann, and Kayar) on the Senegalese coast during the dry and wet seasons, and trace metals content were determined by flame atomic absorption spectrophotometry. The results revealed a high level of contamination at the Rufisque and Soumbedioune sites, mainly related to lead and more pronounced during the dry season. In contrast, cadmium had the highest bioavailable fraction, exceeding 80% during the dry season at the Soumbedioune, Rufisque, and Saint-Louis sites, suggesting an anthropogenic origin for these metals. The results of the test carried out on the marine bacterium Aliivibrio fischeri confirm this observation by highlighting a proven higher toxicity of sediments during the dry season at the Soumbedioune site, followed by Rufisque, compared to the Kayar control site. Ultimately, this work has shown that even though lead contributes more to sediment contamination, the harmful effects on aquatic life are more related to cadmium due to its higher bioavailability. These effects are more pronounced in the dry season and at Soumbedioune due to the discharge of domestic and industrial wastewater without prior treatment.

Published in	International Journal of Ecotoxicology and Ecobiology (Volume 11, Issue 1)
DOI	10.11648/j.ijee.20261101.12
Page(s)	9-18
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2026. Published by Science Publishing Group

Keywords

Trace Metals, Sediments, Bioavailability, Ecotoxicity, Aliivibrio fischeri, Senegalese Coast

1. Introduction

Sediments are ecologically important components of aquatic habitats but also act as a receptacle for various contaminants

[32]

. They are known for their ability to trap pollutants such as trace metals introduced into seas and estuaries by direct industrial and urban effluents, riverine inputs, and atmospheric deposition

[36, 37]

. Trace metals such as Pb, Cd and Hg pose a risk to ecosystem health due to their to their toxicity, persistence, and bioaccumulation potential in aquatic organism

[18, 34]

Variation in environmental parameters can promote the remobilization of trace metals from sediments, thereby increasing their bioavailability and amplifying their toxic effects on the ecosystem

[6]

. Therefore, although chemical analysis of sediments is a relevant tool for assessing the level of pollution in marine environments, it alone is not sufficient to demonstrate the adverse effects on aquatic life

[32]

. Toxicity tests, including the Microtox test, due to their ecological relevance and sensitivity, are necessary to detect these harmful effects on organisms

[14, 20, 31]

The key factor in this test lies in the ability of bioluminescent bacteria such as Aliivibrio fischeri to come into contact with the bioavailable fraction of trace metals in sediments

[22]

. Analyses using Aliivibrio fischeri thus make it possible to assess the bioavailability and potential toxicity of trace metals in marine and estuarine sediments. Several authors have demonstrated that the Aliivibrio fischeri bioassay is a good choice for assessing the toxicity of trace metals in sediments

[22, 32]

In Senegal, anthropogenic pressures in coastal areas steadily increasing. The combined effects of urbanization, industrialization, and the discharge of untreated wastewater, have led to the input of trace metals into the marine environment

[9]

. Trace metals have therefore become one of the main pollutants of seawater and the sedimentary environment of the Senegalese coast, threatening its ecological balance. With this in mind, this study, conducted using an integrated approach (chemical and ecotoxicological analyses), aims to assess the impact of trace metals (Pb and Cd) present in the surface sediments of the Senegalese coast on aquatic life through the marine bacterium Aliivibrio fischeri.

2. Materials and Methods

2.1. Study Area

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Figure 1. Geographic location of sampling sites.

The study area is located along the Senegalese coast, at the western tip of the African continent (Figure 1). Five sampling sites were selected to represent a large part of the coastline, but also according to their degree of anthropization. The sites of Rufisque (Ru), Soumbedioune (So), and Hann (Hn), located near the city of Dakar, are characterized by high urban activity and significant domestic and/or industrial waste

[10]

. The Saint Louis (St) site is located away from significant anthropogenic pressure but close to the mouth of the Senegal River, which carries many pollutants, and the Kayar (Ky) site is some distance from significant anthropogenic influences and serves as a control site for this study.

2.2. Sediment Sample Collection

Surface sediment sample (approximately 5 cm depth) were collected in September 2022 (wet season) and May 2023 (dry season) using sterile polyethylene bags. Upon collection, samples were transported to the laboratory at 4°C and stored at -20°C until analysis for trace metals and Microtox testing.

2.3. Analytical Techniques

2.3.1. Analysis of Total Trace Metals in Sediments

The method described by APHA was used to determine trace metals in sediments

[2]

. Briefly, 1g of dry, 1 g of dry sediment was digested in a mixture of 69% HNO₃ and 37% HCl (1: 3 v/v) at 100°C for 1 hour. The resulting digest was diluted to 50 mL with ultrapure water. Lead and cadmium concentration were determined using an Agilent Technologies Model 240 FS AA flame atomic absorption spectrometer.

2.3.2. Determination of the Bioavailable Fraction of Trace Metals

The bioavailable fraction of trace metals in sediments was determined using the method described by Diop et al

[8]

. In short, 0.5 g of sediment was treated for 24 hours at room temperature and under continuous stirring with 20 mL of 1M HCl. The resulting solution was then centrifuged at 2500 × g for 20 minutes, filtered using a 0.45 µm PTFE syringe filter, and analyzed by flame atomic absorption spectrometry using an Agilent Technologies model 240 FS AA.

2.3.3. Ecotoxicological Analysis

The toxicity of ten surface sediment samples was assessed using the BioTox™ LumoPlate™ Ultimate Matrix kit (EBPI, Mississauga, Ontario, Canada). This method is frequently used to estimate the ecotoxicological risk associated to soil, sediment or water samples

[1, 19, 30, 35]

. Toxicity of sediment samples was measured by observing the decrease in bioluminescence from Aliivibrio fischeri bacteria after 30 minutes of exposure (each sediement sample was tested in duplicate). The measurements were taken using a Varioskan™ LUX multimode microplate reader (Thermo Scientific, Fisher Scientific SAS, Illkirch, France). Manufacturer’s instructions were scrupulously followed. Brefly, two grams of sediment were mixed with 8 mL of sample diluent for 5 minutes (LumoPlate™ Ultimate Matrix kit, reagent 1243–125) and 2-folds serial dilutions were performed to create concentration gradients. These gradients were used to determine the EC50 values, representing the concentration that inhibits 50% of bacterial luminescence (ISO/TC 147/SC 5 2007)

[26]

. Higher toxicity resulted in a greater reduction in luminescence and are traduced by low EC50 values.

2.4. Parameters for Assessing Potential Effects Related to Sediment Pollution

In this study, the degree of contamination (Cdeg), the potential ecological risk index (RI), and adverse effect index (AEI) were determined to assess the impact of trace metal contamination in sediments on biota.

2.4.1. Degree of Sediment Contamination

The overall level of sediment contamination by trace metals is assessed by the contamination factor (CF) determined using the following equation (1):

{CF}_{n} = \frac{C_{η}}{C_{m}}

(1)

Where C_n(mg/kg) represents the concentration of bioavailable trace metals in a sediment sample and C_m (mg/kg) represents the value for the reference sediment

[17]

The degree of contamination (Cdeg) was calculated using the equation (2) described by

[17]

. It allows the level of pollution at sites to be determined by adding together the contamination factors for the trace metals studied.

C_{\deg} = \sum_{1}^{n} {CF}_{i}

(2)

2.4.2. Potential Ecological Risk Index

The potential ecological risk index (RI) was used to assess the ecological risk posed by bioavailable trace metals in sediments. This index, originally proposed by

[17]

is calculated using the following equation (3):

RI = \sum_{0}^{n} E_{r}^{n} = \sum_{0}^{n} {T_{r}}^{n} {CF}_{n}

(3)

where

E_{r}^{n}

is the potential ecological risk coefficient for metal

n

T_{r}^{n}

is the toxicity factor of metal

n

, and

C F_{n}

is the contamination factor. In this study, toxicity factors of 5 for Pb and 30 for Cd were applied. The resulting RI values were classified into five risk categories (Table 1).

Table 1. Classification of potential ecological risk

[17]

Er		RI
Level	Classification	Level	Classification
$E_{r}^{n}$ < 40	Low risk	RI <150	Ecological risk
40 ≤ < 80 $E_{r}^{n}$	Moderate risk	150 ≤ RI 300 <	Moderate ecological risk
80 ≤ < 160 $E_{r}^{n}$	Considerable risk	300 ≤ RI <600	Significant ecological risk
160 ≤ < 320 $E_{r}^{n}$	High risk	RI≥ 600	Very high ecological risk
$E_{r}^{n}$ ≥ 320	Very high risk	-	-

2.4.3. Index of Adverse Effects

The adverse effects index (AEI) was used to estimate the risks associated with biota exposure to the bioavailable fraction of trace metals in sediment

[25]

. It was calculated using the low-effect range (ERL) developed by Long et al

[21]

. This index involves the concentration of bioavailable trace metals in sediment relative to the concentration above which adverse effects on biota are likely to occur

[27]

. The calculations were performed using the equation (4):

AEI = \frac{C_{n}}{ERL}

(4)

Where C_n (mg/kg) represents the bioavailable concentration of the metal in the sediment and ERL (mg/kg) represents the range of low effects.

If AEI ≤ 1: no adverse effects on biota.

If AEI ≥ 1: adverse effects on biota

[27]

2.5. Statistical Data Processing

The data were recorded and statistically processed using Microsoft Excel 2019 and SPSS 24.0.12 (Statistical Package for the Social Sciences). Differences in toxicity and bioavailability of trace metals in sediments were analyzed using one-way ANOVA. Principal component analysis (PCA) was used to explore the relationships between the observed effects and the bioavailable fraction of metals in sediments.

3. Results and Discussion

3.1. Trace Metals Concentrations in Sediments

The results of the total trace metals content of the sediments are recorded in Table 2.

Table 2. Total trace metals concentrations (mg/kg) in surface sediments along the Senegalese coast.

Site	Season	Pb (mg/kg)	Cd (mg/kg)
Ru	Dry	44.51±4.50	3.15±0.02
Ru	Wet	31.20 ±2.83	2.26 ±0.01
So	Dry	28.39 ±6.42	3.75 ±0.02
So	Wet	41.90 ±2.71	2.48 ±0.62
St	Dry	22.89 ±2.33	2.51±0.08
St	Wet	20.92 ±10.61	2.32±0.15
Hn	Dry	26.78 ±0.52	1.58±0.68
Hn	Wet	19.08 ±8.11	1.66 ±0.06
Ky	Dry	21.78 ±4.37	0.77±0.29
Ky	Wet	21.31 ±4.96	0.29 ±0.06
ERL		46.7	1.2
ERM		218	9.6

ERL: low effect range; ERM: median effect range

The highest Pb concentrations were recorded at the Ru site during the dry season at 44.51 mg/kg and at the So site during the wet season at 41.90 mg/kg. These levels are below the low-effect range (ERL) and median-effect range (ERM) for the protection of aquatic life, which are 46.7 mg/kg and 218 mg/kg, respectively

[21]

With regard to Cd, the highest concentration (3.75 mg/kg) was recorded at the So site during the dry season. This exceeds the ERL value for the protection of aquatic life, which is 1.20 mg/kg

[21]

, and can be explained by the discharge of untreated domestic wastewater from hospitals and homes in a large part of the city of Dakar via Canal 4

[7]

. However, it should be noted that these comparisons with ecotoxicological reference values concern the total concentrations of trace metals in sediments. Indeed, several studies have now shown that the total concentration of trace metals cannot characterize the ecotoxicological risks of sediments, as only the bioavailable fraction of trace metals is toxic to aquatic organisms

[3]

Thus, the concentrations and percentages of bioavailable fractions of trace metals in sediments are presented in Table 3.

Table 3. Average values of bioavailable concentrations of trace metals (mg/kg) and percentage of the bioavailable fraction.

Site	Season	Cd	%bioavailable	Pb	%bioavailable
Ru	Dry	2.68±0.08	85	24.95±1.44	56
Ru	Wet	0.77±0.15	34	16.65±0.75	53
So	Dry	3.45±0.15	92	26.40±0.08	93
So	Wet	1.48±0.16	60	37.65±4.42	90
St	Dry	2.1±0.05	84	8±0.71	35
St	Wet	0.6±0.05	26	7.60±1.21	36
Hn	Dry	0.43±0.05	27	6.50±0.83	24
Hn	Wet	0.35±0.06	21	9.55±1.22	50
Ky	Dry	0.28±0.10	36	4.15±0.38	19
Ky	Wet	0.17±0.07	59	5.2±0.38	24

With the exception of the Ky site during the dry season, where the percentage of Pb bioavailability is less than 20%, the other sites showed bioavailable fractions ranging from 21 to 93% in all seasons. This suggests high mobility and bioavailability of these elements. In the literature, the work of Monte et al. and Freitas et al. has indicated an increase in the bioavailability of trace metals after sediment resuspension, caused by factors such as bioturbation and anthropogenic factors such as dredging and sediment discharge

[13, 24]

. When sediments are resuspended, various physicochemical changes can occur, including changes in redox potential, leading to the remobilization of elements associated with sediment particles

[5]

, particularly in polluted areas

[11, 12]

. These observations corroborate our results, since the highest bioavailable fractions were noted in Soumbedioune and Rufisque, which are our most polluted sites. In addition, dilution phenomena associated with a greater input of organic matter by rain during the wet season may explain the decrease in bioavailability during this season. Indeed, high organic matter content complexifies metals, reducing their mobility and bioavailability to aquatic organisms

[28, 33]

. Our results are similar to those obtained by Diop et al. on the Dakar coast and the Saint-Louis estuary, indicating significant mobility and bioavailability of Pb and Cd, particularly in the dry season

[8]

3.2. Sediment Ecotoxicity Through Inhibition of Aliivibrio fischeri Bioluminescence

EC50 were determined through the bioluminescence of Aliivibrio fischeri was determined using 7 dilutions of six replicates of each sediment samples. After 30 min of exposure, the Ky control site exhibited no toxicity to minor toxicity (EC50 greater than 200 mg/mL during the dry season and above 121.7 mg/mL during the wet season) towards Aliivibrio fischeri (Figure 2).

However, the bacterium Aliivibrio fischeri was highly affected when exposed to sediments from the So and Ru sites during the dry season, with respective EC50 concentrations of 7.9 mg/mL and 14.3 mg/mL corresponding to intermediate to high toxicity

[4]

. All samples collected during the wet season, as well as for samples from St and Hn collected during the dry season, exhibited low toxicity with values ranging from 27 to 117.6 mg/mL. The highest toxicity of So and Ru samples collected during the dry season can be related to the high concentrations of Pb and Cd in sediments, with the highest bioavailable fractions greater than 80%. The toxicity detected by the bacteria would therefore be linked to the trace metals content of the sediments and, above all, to their high bioavailability. Indeed, the bioassay on Aliivibrio fischeri is recognized for its high sensitivity in detecting the toxicity of bioavailable trace metals

[22]

. It is therefore a good bioindicator for characterizing the ecotoxicological risks of trace metals in sediments

[29]

. In general, at all sites except the control site, EC 50 values are lower in the dry season than in the wet season, suggesting greater sediment toxicity during the dry season. These results correlate with the levels of bioavailable trace metal concentrations in sediments during the dry season.

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Figure 2. Inhibition of Aliivibrio fischeri bioluminescence in sediments. D = dry season, W = wet season.

3.3. Assessment of Potential Sediment Effects

3.3.1. Contamination Factor (CF) and Degree of Contamination (Cdeg)

The results relating to the factors and degree of contamination are presented in Table 4. They reveal low to considerable trace metal contamination in sediments at all sites. Only the Ru site in the dry season and the So site in the dry and wet seasons showed contamination levels above 11, corresponding to a high level of pollution characterized by a significant contribution from Pb. This high contribution of Pb to sediment pollution suggests an anthropogenic origin for this metal in our study area. Indeed, numerous studies have revealed that the discharge of untreated domestic and/or industrial wastewater into aquatic environments, as well as atmospheric deposits from fuels and waste incineration, are sources of metals, including lead, in the aquatic environment

[3, 15]

Table 4. Contamination factor (CF) and contamination degree (Cdeg) calculated for bioavailable trace metals in sediment samples collected from various sites along the coast of Dakar and the Saint-Louis estuary.

Site	Season	CF		Cdeg
Site	Season	Cd	Pb	Cdeg
Ru	Dry	2.83±0.08	6.24±0.36	9.26±0.43
Ru	Wet	0.81±0.16	4.17±0.19	5.13±0.29
So	Dry	3.64±0.08	7.15±0.36	11.25±0.43
So	Wet	1.56±0.16	9.42±1.11	11.22±1.00
St	Dry	2.21±0.05	2±0.18	4.37±0.19
St	Wet	0.61±0.06	1.9±0.30	2.66±0.28
Hn	Dry	1.56±0.06	1.63±0.21	3.42±0.16
Hn	Wet	0.18±0.08	2.39±0.30	2.77±0.28
Ky	Dry	0.79±0.11	1.04±0.09	1.99±0.02
Ky	Wet	0.39±0.06	1.3±0.15	1.84±0.20

3.3.2. Potential Ecological Risk Index

The ecological risk potential coefficient (Er) and the ecological risk potential index (RI) were determined in order to understand individually and aggregate the ecological risk potential of Pb and Cd in sediment. The results are presented in Table 5. The average Er values for Pb were below 40 at all sites, except for the So site in the wet season, which had a moderate risk level [40 < Er < 80] with an Er of 47.12. Cd presented a considerable risk level [80 < Er < 160] on average for the So (109.08) and Ru (84.84) sites during the dry season. These results therefore indicate a low to moderate potential ecological risk to aquatic organisms, particularly in relation to cadmium

[16]

. The RI classification places each of these sites in the low ecological risk category (RI < 150). These results are consistent with those of Mohajane et al whose risk index indicated a low potential ecological risk, although heavy metal analysis showed concentrations above sediment quality criteria at all sites

[23]

Table 5. Er and RI calculated for bioavailable trace metals in sediment samples collected from various sites along the coast of Dakar and the Saint-Louis estuary.

Site	Season	Er		RI
Site	Season	Cd	Pb	RI
Ru	Dry	84.84±2.41	31.22±1.80	116.25±3.97
Ru	Wet	16.33±10.53	20.84±0.94	37.38±9.52
So	Dry	109.08±4.74	35.73±0.11	145.28±4.77
So	Wet	7.82±0.80	47.12±5.53	55.4±4.98
St	Dry	66.4±1.58	10.01±0.89	76.56±1.97
St	Wet	3.07±0.30	9.51±1.52	12.86±1.39
Hn	Dry	46.9±1.83	8.13±1.03	55.27±1.11
Hn	Wet	0.88±0.40	11.95±1.52	13.24±1.39
Ky	Dry	23.71±3.16	5.19±0.47	29.06±2.69
Ky	Wet	1.93±0.30	6.51±0.76	8.75±1.02

3.3.3. Index of Adverse Effects of Bioavailable Trace Metals on Biota

The adverse effects index (AEI) is used to estimate the probability of toxicity to living organisms in sediments

[25]

. The adverse effects index values obtained for Pb are less than 1 at all sites during both seasons (Table 6). This suggests a low risk of potential biological effects on aquatic organisms for Pb. In contrast, Cd had values greater than or equal to 1 at the So sites in the dry and wet seasons, and at the Ru and St sites in the dry season, which can be explained by the greater bioavailability of this element in the sediment at these sites. Similar results were reported by

[25]

. Indeed, these three bays have a high degree of anthropization, including high urban activity and significant domestic and/or industrial discharges

[10]

, which may explain the high bioavailability of Cd at these sites. These observations are confirmed by the results of the experimental study on the inhibition of Aliivibrio fischeri bioluminescence by sediments from the So and Ru sites, which induced the highest toxicity compared to the other study sites.

Download: Download full-size image

Figure 3. PCA linking the observed effects (EC50) on Aliivibrio fischeri to the levels of bioavailable metals (Pb, Cd) in sediments at the study sites during the dry season (D) and wet season (W).

Table 6. Adverse Effects Index (AEI) for surface sediments along the coast of Dakar and in the Saint-Louis estuary.

Site	Season	Cd	Pb
Ru	Dry	2.23	0.53
Ru	Wet	0.64	0.35
So	Dry	2.87	0.56
So	Wet	1.23	0.8
St	Dry	1.75	0.17
St	Wet	0.5	0.16
Hn	Dry	0.35	0.14
Hn	Wet	0.29	0.20
Ky	Dry	0.23	0.08
Ky	Wet	0.14	0.11

These observations are consistent with the results of the experimental study on the inhibition of Aliivibrio fischeri bioluminescence by sediments from the So and Ru sites, which induced the highest toxicity compared to the other study sites. Multivariate statistical analysis using PCA confirms the relationship between the bioavailable fraction of trace metals (Pb, Cd) and toxicity (EC50) observed in Aliivibrio fischeri bacteria after exposure to sediments from our various study sites (Figure 3). The first two axes (dim 1 and dim 2) explain 90.4% of the total data information, with a strong negative correlation between EC50 and the bioavailable fraction of Cd in Soumbedioune and Rufisque during the dry season. This confirms the link between the effects observed on Aliivibrio fischeri and the levels of bioavailable trace metals in the sediments.

4. Conclusion

This study focused on assessing the toxicity of surface sediments at certain sites along the Senegalese coast by determining the bioavailable fraction of trace metals using the Microtox acute test. Overall, our results showed that the Soumbedioune site is considered polluted by Cd in both the dry and wet seasons, and the Rufisque site by Pb in the dry season. Despite these pollution levels, the potential ecological risk index values classify each of the sites in this study as low risk. Nevertheless, the adverse effects index for Cd at the Soumbedioune, Rufisque, and Saint-Louis sites suggests potential effects of this element on living organisms in the sediments. These observations are confirmed by the results of toxicity tests on Aliivibrio fischeri bacteria, which revealed higher toxicity in sediments at the Soumbedioune and Rufisque sites during the dry season. Thus, the analysis carried out as part of this study showed that Pb contributes more to sediment pollution by trace metals; on the other hand, cadmium has the most harmful effects on aquatic life due to its greater bioavailability. These effects are more pronounced in the dry season, and Soumbedioune is the most impacted site due to the discharge of domestic and industrial wastewater without prior treatment.

Abbreviations

AEI	Adverse Effects Index
Cdeg	Degree of Contamination
CF	Contamination Factor
D	Dry Season
Er	Potential Ecological Risk Coefficient
ERL	Low Effect Range
ERM	Median Effect Range
Hn	Hann
Ky	Kayar
RI	Potential Ecological Risk Index
Ru	Rufisque
So	Soumbedioune
St	Saint-Louis
W	Wet Season

Acknowledgments

This document was produced with financial assistance from the Senegalese Ministry of Higher Education, Research and Innovation.

Author Contributions

Jessica Carmelia Mbemba Peleka: Conceptualization, Data curation, Methodology, Writing – original draft

Anthony Verdin: Methodology, Writing – review & editing

Mathilda Osiris Mahouekpo: Data curation, Methodology

Robert Faomowe Foko: Data curation, Methodology

Fatoumata Gueye: Formal Analysis

Fatoumata Bah: Data curation, Writing – review & editing

Aminata Toure: Visualization, Writing – review & editing

Mathilde Cabral: Visualization, Writing – review & editing

Mamadou Fall: Validation, Visualization

Cheikh Diop: Conceptualization, Supervision, Writing – review & editing, Project administration

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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Peleka, J. C. M., Verdin, A., Mahouekpo, M. O., Foko, R. F., Gueye, F., et al. (2026). Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. International Journal of Ecotoxicology and Ecobiology, 11(1), 9-18. https://doi.org/10.11648/j.ijee.20261101.12

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Peleka, J. C. M.; Verdin, A.; Mahouekpo, M. O.; Foko, R. F.; Gueye, F., et al. Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. Int. J. Ecotoxicol. Ecobiol. 2026, 11(1), 9-18. doi: 10.11648/j.ijee.20261101.12

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Peleka JCM, Verdin A, Mahouekpo MO, Foko RF, Gueye F, et al. Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. Int J Ecotoxicol Ecobiol. 2026;11(1):9-18. doi: 10.11648/j.ijee.20261101.12

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@article{10.11648/j.ijee.20261101.12,
  author = {Jessica Carmelia Mbemba Peleka and Anthony Verdin and Mathilda Osiris Mahouekpo and Robert Faomowe Foko and Fatoumata Gueye and Fatoumata Bah and Aminata Toure and Mathilde Cabral and Mamadou Fall and Cheikh Diop},
  title = {Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri},
  journal = {International Journal of Ecotoxicology and Ecobiology},
  volume = {11},
  number = {1},
  pages = {9-18},
  doi = {10.11648/j.ijee.20261101.12},
  url = {https://doi.org/10.11648/j.ijee.20261101.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijee.20261101.12},
  abstract = {Bioavailable trace metals in sediments can be a significant source of contamination for aquatic organisms. The present study aims to evaluate the overall toxicity of the bioavailable fraction of Pb and Cd in sediments from the Senegalese coast on the bacterium Aliivibrio fischeri. Surface sediment samples were collected at five sites (Rufisque, Soumbedioune, Saint-Louis, Hann, and Kayar) on the Senegalese coast during the dry and wet seasons, and trace metals content were determined by flame atomic absorption spectrophotometry. The results revealed a high level of contamination at the Rufisque and Soumbedioune sites, mainly related to lead and more pronounced during the dry season. In contrast, cadmium had the highest bioavailable fraction, exceeding 80% during the dry season at the Soumbedioune, Rufisque, and Saint-Louis sites, suggesting an anthropogenic origin for these metals. The results of the test carried out on the marine bacterium Aliivibrio fischeri confirm this observation by highlighting a proven higher toxicity of sediments during the dry season at the Soumbedioune site, followed by Rufisque, compared to the Kayar control site. Ultimately, this work has shown that even though lead contributes more to sediment contamination, the harmful effects on aquatic life are more related to cadmium due to its higher bioavailability. These effects are more pronounced in the dry season and at Soumbedioune due to the discharge of domestic and industrial wastewater without prior treatment.},
 year = {2026}
}

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TY  - JOUR
T1  - Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri
AU  - Jessica Carmelia Mbemba Peleka
AU  - Anthony Verdin
AU  - Mathilda Osiris Mahouekpo
AU  - Robert Faomowe Foko
AU  - Fatoumata Gueye
AU  - Fatoumata Bah
AU  - Aminata Toure
AU  - Mathilde Cabral
AU  - Mamadou Fall
AU  - Cheikh Diop
Y1  - 2026/04/16
PY  - 2026
N1  - https://doi.org/10.11648/j.ijee.20261101.12
DO  - 10.11648/j.ijee.20261101.12
T2  - International Journal of Ecotoxicology and Ecobiology
JF  - International Journal of Ecotoxicology and Ecobiology
JO  - International Journal of Ecotoxicology and Ecobiology
SP  - 9
EP  - 18
PB  - Science Publishing Group
SN  - 2575-1735
UR  - https://doi.org/10.11648/j.ijee.20261101.12
AB  - Bioavailable trace metals in sediments can be a significant source of contamination for aquatic organisms. The present study aims to evaluate the overall toxicity of the bioavailable fraction of Pb and Cd in sediments from the Senegalese coast on the bacterium Aliivibrio fischeri. Surface sediment samples were collected at five sites (Rufisque, Soumbedioune, Saint-Louis, Hann, and Kayar) on the Senegalese coast during the dry and wet seasons, and trace metals content were determined by flame atomic absorption spectrophotometry. The results revealed a high level of contamination at the Rufisque and Soumbedioune sites, mainly related to lead and more pronounced during the dry season. In contrast, cadmium had the highest bioavailable fraction, exceeding 80% during the dry season at the Soumbedioune, Rufisque, and Saint-Louis sites, suggesting an anthropogenic origin for these metals. The results of the test carried out on the marine bacterium Aliivibrio fischeri confirm this observation by highlighting a proven higher toxicity of sediments during the dry season at the Soumbedioune site, followed by Rufisque, compared to the Kayar control site. Ultimately, this work has shown that even though lead contributes more to sediment contamination, the harmful effects on aquatic life are more related to cadmium due to its higher bioavailability. These effects are more pronounced in the dry season and at Soumbedioune due to the discharge of domestic and industrial wastewater without prior treatment.
VL  - 11
IS  - 1
ER  -

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Author Information

Jessica Carmelia Mbemba Peleka

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0009-0003-2498-3646
Anthony Verdin

Environmental Chemistry and Live Interactions Unit, University of Littoral Côte d'Opale, Dunkerque, France

http://orcid.org/0000-0003-3438-9854
Mathilda Osiris Mahouekpo

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0009-0003-7335-6307
Robert Faomowe Foko

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0000-0002-4859-8385
Fatoumata Gueye

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal
Fatoumata Bah

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0000-0002-8558-5313
Aminata Toure

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0000-0001-5629-849X
Mathilde Cabral

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0000-0001-7257-5979
Mamadou Fall

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal

http://orcid.org/0000-0001-8588-8309
Cheikh Diop

Laboratory of Toxicology and Hydrology, Cheikh Anta Diop University, Dakar, Senegal;IRL3189 ESS CNRS, Cheikh Anta Diop University, Dakar, Senegal

Contact Email

http://orcid.org/0000-0001-8623-573X

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Peleka, J. C. M., Verdin, A., Mahouekpo, M. O., Foko, R. F., Gueye, F., et al. (2026). Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. International Journal of Ecotoxicology and Ecobiology, 11(1), 9-18. https://doi.org/10.11648/j.ijee.20261101.12

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ACS Style

Peleka, J. C. M.; Verdin, A.; Mahouekpo, M. O.; Foko, R. F.; Gueye, F., et al. Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. Int. J. Ecotoxicol. Ecobiol. 2026, 11(1), 9-18. doi: 10.11648/j.ijee.20261101.12

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AMA Style

Peleka JCM, Verdin A, Mahouekpo MO, Foko RF, Gueye F, et al. Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri. Int J Ecotoxicol Ecobiol. 2026;11(1):9-18. doi: 10.11648/j.ijee.20261101.12

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@article{10.11648/j.ijee.20261101.12,
  author = {Jessica Carmelia Mbemba Peleka and Anthony Verdin and Mathilda Osiris Mahouekpo and Robert Faomowe Foko and Fatoumata Gueye and Fatoumata Bah and Aminata Toure and Mathilde Cabral and Mamadou Fall and Cheikh Diop},
  title = {Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri},
  journal = {International Journal of Ecotoxicology and Ecobiology},
  volume = {11},
  number = {1},
  pages = {9-18},
  doi = {10.11648/j.ijee.20261101.12},
  url = {https://doi.org/10.11648/j.ijee.20261101.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijee.20261101.12},
  abstract = {Bioavailable trace metals in sediments can be a significant source of contamination for aquatic organisms. The present study aims to evaluate the overall toxicity of the bioavailable fraction of Pb and Cd in sediments from the Senegalese coast on the bacterium Aliivibrio fischeri. Surface sediment samples were collected at five sites (Rufisque, Soumbedioune, Saint-Louis, Hann, and Kayar) on the Senegalese coast during the dry and wet seasons, and trace metals content were determined by flame atomic absorption spectrophotometry. The results revealed a high level of contamination at the Rufisque and Soumbedioune sites, mainly related to lead and more pronounced during the dry season. In contrast, cadmium had the highest bioavailable fraction, exceeding 80% during the dry season at the Soumbedioune, Rufisque, and Saint-Louis sites, suggesting an anthropogenic origin for these metals. The results of the test carried out on the marine bacterium Aliivibrio fischeri confirm this observation by highlighting a proven higher toxicity of sediments during the dry season at the Soumbedioune site, followed by Rufisque, compared to the Kayar control site. Ultimately, this work has shown that even though lead contributes more to sediment contamination, the harmful effects on aquatic life are more related to cadmium due to its higher bioavailability. These effects are more pronounced in the dry season and at Soumbedioune due to the discharge of domestic and industrial wastewater without prior treatment.},
 year = {2026}
}

Copy | Download

TY  - JOUR
T1  - Assessment of the Overall Ecotoxicity Associated with the Bioavailable Fraction of Trace Metals in Surface Sediments Along the Senegalese Coast on Aliivibrio fischeri
AU  - Jessica Carmelia Mbemba Peleka
AU  - Anthony Verdin
AU  - Mathilda Osiris Mahouekpo
AU  - Robert Faomowe Foko
AU  - Fatoumata Gueye
AU  - Fatoumata Bah
AU  - Aminata Toure
AU  - Mathilde Cabral
AU  - Mamadou Fall
AU  - Cheikh Diop
Y1  - 2026/04/16
PY  - 2026
N1  - https://doi.org/10.11648/j.ijee.20261101.12
DO  - 10.11648/j.ijee.20261101.12
T2  - International Journal of Ecotoxicology and Ecobiology
JF  - International Journal of Ecotoxicology and Ecobiology
JO  - International Journal of Ecotoxicology and Ecobiology
SP  - 9
EP  - 18
PB  - Science Publishing Group
SN  - 2575-1735
UR  - https://doi.org/10.11648/j.ijee.20261101.12
AB  - Bioavailable trace metals in sediments can be a significant source of contamination for aquatic organisms. The present study aims to evaluate the overall toxicity of the bioavailable fraction of Pb and Cd in sediments from the Senegalese coast on the bacterium Aliivibrio fischeri. Surface sediment samples were collected at five sites (Rufisque, Soumbedioune, Saint-Louis, Hann, and Kayar) on the Senegalese coast during the dry and wet seasons, and trace metals content were determined by flame atomic absorption spectrophotometry. The results revealed a high level of contamination at the Rufisque and Soumbedioune sites, mainly related to lead and more pronounced during the dry season. In contrast, cadmium had the highest bioavailable fraction, exceeding 80% during the dry season at the Soumbedioune, Rufisque, and Saint-Louis sites, suggesting an anthropogenic origin for these metals. The results of the test carried out on the marine bacterium Aliivibrio fischeri confirm this observation by highlighting a proven higher toxicity of sediments during the dry season at the Soumbedioune site, followed by Rufisque, compared to the Kayar control site. Ultimately, this work has shown that even though lead contributes more to sediment contamination, the harmful effects on aquatic life are more related to cadmium due to its higher bioavailability. These effects are more pronounced in the dry season and at Soumbedioune due to the discharge of domestic and industrial wastewater without prior treatment.
VL  - 11
IS  - 1
ER  -

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