Fingerprinting Environmental Contaminants in Lemna Dumpsites: A Biomarker-Based Approach for Assessing Ecological Risk in Tropical Regions

• Authors: Paul Bassey Ekpo , Inyang Paul Ekpo , Henderson Onah Ogbaji , Florence Ben Unoh , Osondu-Anyanwu Chinyere , Emmanuella Oghenetega Onajite
• Languages of publication: EN

Abstracts

EN

This study evaluated environmental contamination and biological stress at the Lemna dumpsite in Calabar Municipality, Nigeria, through integrated biochemical and physicochemical analyses. Soil and water samples were assessed for oxidative stress biomarkers, DNA damage, lipid peroxidation, and contaminant levels. Enzymatic activities of catalase (4.82 ± 0.21 U/mg protein), peroxidase (2.91 ± 0.17 U/mg protein), and glutathione S-transferase (5.34 ± 0.22 U/mg protein) were significantly elevated in soil samples compared to water (3.15 ± 0.18, 1.87 ± 0.14, and 3.92 ± 0.19 U/mg protein, respectively), indicating increased oxidative stress in soil microbial communities exposed to heavy metals and organic pollutants. The comet assay revealed pronounced DNA fragmentation in soil microbes, with tail length of 38.6 ± 2.4 µm and 52.4 ± 3.1% DNA in tail, compared to water samples (27.2 ± 2.1 µm and 40.8 ± 2.7%). Lipid peroxidation, measured by malondialdehyde concentration, was also higher in soil samples (8.12 ± 0.31 nmol MDA/g) than in water (5.76 ± 0.29 nmol MDA/g), confirming oxidative membrane damage. Physicochemical analyses showed acidic soil pH (5.4 ± 0.2), elevated total organic carbon (4.3 ± 0.5%), and heavy metal concentrations of lead (62.5 ± 3.2 mg/kg), cadmium (3.1 ± 0.2 mg/kg), and chromium (77.2 ± 4.1 mg/kg), all exceeding WHO permissible limits. Water quality assessment indicated slightly acidic pH (6.2 ± 0.3), high turbidity (22.5 ± 1.7 NTU), and significant microbial pollution with total coliforms at 920 MPN/100 mL and positive E. coli presence, reflecting fecal contamination likely from leachate. These findings demonstrate severe environmental degradation at the dumpsite, with clear biological effects on soil microorganisms and public health risks from contaminated water. The study underscores the urgent need for remediation strategies, improved waste management, and continuous environmental monitoring to mitigate ecological and human health impacts.

Keywords

EN

DNA damage; Environmental contamination; Lemna dumpsite; biomarker analysis; heavy metals; microbial pollution; oxidative stress

Discipline

• BIOCHEMISTRY: BIOCHEMISTRY

• Publisher: Scientific Publishing House „DARWIN”
• Journal: World News of Natural Sciences
• Year: 2025
• Volume: 62
• Pages: 167-182

Contributors

author

Paul Bassey Ekpo

• Department of Genetics and Biotechnology, Faculty of Biological Sciences, University of Calabar, Calabar, Cross River State, Nigeria

author

Inyang Paul Ekpo

• Department of Fisheries and Aquaculture, Faculty of Agriculture, University of Calabar, Calabar, Cross River State, Nigeria

author

Henderson Onah Ogbaji

• Department of Genetics and Biotechnology, Faculty of Biological Sciences, University of Calabar, Calabar, Cross River State, Nigeria

author

Florence Ben Unoh

• Department of Science Laboratory Technology, Faculty of Biological Sciences, University of Calabar, Calabar, Cross River State, Nigeria

author

Osondu-Anyanwu Chinyere

author

Emmanuella Oghenetega Onajite

• Department of Genetics and Biotechnology, Faculty of Biological Sciences, University of Calabar, Calabar, Cross River State, Nigeria

References

• [1] Adeola, O., & Onwudiwe, C. (2021). Impact of tropical climatic conditions on leachate generation and contaminant transport from dumpsites. Environmental Science and Pollution Research, 28(12), 15023-15035. https://doi.org/10.1007/s11356-020-12054-7
• [2] Adeyemi, O., & Akinola, O. (2020). Waste management challenges in tropical urban centers: A case study of municipal dumpsites. Journal of Environmental Management, 256, 109954. https://doi.org/10.1016/j.jenvman.2019.109954
• [3] Alloway, B. J. (2013). Heavy metals in soils: Trace metals and metalloids in soils and their bioavailability (3rd ed.). Springer.
• [4] APHA. (2017). Standard methods for the examination of water and wastewater (23rd ed.). American Public Health Association.
• [5] Ayala, A., Muñoz, M. F., & Argüelles, S. (2014). Lipid peroxidation: Production, metabolism, and signaling mechanisms of malondialdehyde and 4-hydroxy-2-nonenal. Oxidative Medicine and Cellular Longevity, 2014, Article 360438. https://doi.org/10.1155/2014/360438
• [6] Barata, C., Baird, D. J., & Soares, A. M. V. M. (2023). Biomarkers in aquatic toxicology: Applications and perspectives. Ecotoxicology, 32(1), 1-15. https://doi.org/10.1007/s10646-022-02587-5
• [7] Beyer, J., Triebskorn, R., & Köhler, H.-R. (2011). Environmental biomarkers: Linking physiological responses to contaminant exposure. Ecotoxicology, 20(2), 197-214. https://doi.org/10.1007/s10646-011-0705-9
• [8] Cedergreen, N. (2010). Quantifying synergy: A systematic review of mixture toxicity studies within environmental toxicology. PLOS ONE, 5(11), e11513. https://doi.org/10.1371/journal.pone.0011513
• [9] Chen, X., Patel, S., & Zhang, Y. (2024). Isotopic fingerprinting for source apportionment of heavy metals in tropical dumpsite soils. Environmental Pollution, 312, 120096. https://doi.org/10.1016/j.envpol.2023.120096
• [10] Chukwuemeka, P., & Okoro, C. (2019). Assessment of heavy metal contamination in soils and water near municipal dumpsites in Nigeria. Environmental Monitoring and Assessment, 191(4), 234. https://doi.org/10.1007/s10661-019-7431-8
• [11] Collins, A. R. (2014). The comet assay for DNA damage and repair: Principles, applications, and limitations. Molecular Biotechnology, 26(3), 249-261. https://doi.org/10.1007/s12033-014-9836-x
• [12] Depledge, M. H., & Fossi, M. C. (1994). The role of biomarkers in environmental assessment (2). Marine Pollution Bulletin, 28(1), 7-13. https://doi.org/10.1016/0025-326X(94)90002-7
• [13] Ekpo, P. B., Ekpo, I. P., Ifon, H. T., & Uren, S. E. (2021). Assessing the impact of water quality disturbances on plankton dynamics in Great Kwa River, Nigeria; implications for ecological health and biodiversity. International Journal of Applied Sciences, 14, 149-155
• [14] Ekpo, P. B., Ekpo, I. P., Ifon, H. T., & Edet, A. R. (2021). Ecological indices of zooplankton communities in the Great Kwa River, Nigeria (Special Edition). International Journal of Applied Sciences, 14, 156-162
• [15] Ekpo, P. B., & Ubi, G. M. (2022). Phytoremediation potentials and hyperaccumulation of heavy metals by Moringa oleifera and profiling of hydrocarbon-utilizing microbes on crude oil-polluted soils of Niger Delta. International Journal of Applied Sciences, 15, 1-6
• [16] Ekpo, P. B., & Okey, F. O. (2020). Assessment of heavy metals in leachates from Lemna dumpsite in Calabar Municipality of Cross River State. Journal of Nigeria Environment Society, 13(1), 105-125
• [17] Ekpo, P. B., Ekpo, I. P., Ikongshul, A. A., Idung, J. U., Ekerette, E. E., Reagan, B. A., Edu, N. E., Ogbe, H. O., & Eyo, V. E. (2024). Evaluating Citrus limon and Carica papaya seed extracts in coagulation-flocculation for improved water quality: Implications for treatment plants. Global Journal of Pure and Applied Sciences, 30, 1118–0579.
• [18] Ekpo, P. B., Etangetuk, N. A., Agu, R. C., Chinyere, O. A., Nwachukwu, A. A., Nkang, N. A., & Ekpo, I. P. (2023). An assessment of the effect of pollution on zooplanktons in Calabar Great Kwa River, Nigeria. Journal of Advances in Biology & Biotechnology, 26(3), 11-16
• [19] Eze, S. C., Udo, I. O., & Okafor, J. C. (2020). Heavy metal and PAH contamination in soils and water near Lemna dumpsite, Calabar, Nigeria. Environmental Toxicology and Chemistry, 39(5), 1032-1041. https://doi.org/10.1002/etc.4698
• [20] Fernandez, M., Kumar, S., & Patel, R. (2022). Persistent organic pollutants and emerging contaminants in tropical dumpsite leachates. Science of The Total Environment, 807, 150755. https://doi.org/10.1016/j.scitotenv.2021.150755
• [21] Foley, J. A., et al. (2005). Global consequences of land use. Science, 309(5734), 570-574. https://doi.org/10.1126/science.1111772
• [22] Gomes, F., Barata, C., & Soares, A. M. V. M. (2021). Bioindicators in tropical aquatic ecosystems: A review. Ecotoxicology and Environmental Safety, 208, 111631. https://doi.org/10.1016/j.ecoenv.2020.111631
• [23] Gupta, N., & Singh, R. (2018). Socioeconomic factors influencing waste management practices in tropical urban areas. Waste Management, 72, 1-10. https://doi.org/10.1016/j.wasman.2017.10.027
• [24] Habig, W. H., Pabst, M. J., & Jakoby, W. B. (1974). Glutathione S-transferases: The first enzymatic step in mercapturic acid formation. Journal of Biological Chemistry, 249(22), 7130-7139
• [25] Hill, W. R., Mulholland, P. J., DeNicola, D. M., Kuang, Y., & Orlando, J. L. (1992). The use of Lemna minor in ecotoxicological testing. Environmental Toxicology and Chemistry, 11(12), 1709-1717. https://doi.org/10.1002/etc.5620111212
• [26] Ibrahim, A., & Musa, A. (2018). Environmental impact of heavy metals in tropical dumpsites: A review. Environmental Science and Pollution Research, 25(9), 8573-8585. https://doi.org/10.1007/s11356-018-1444-9
• [27] Jones, K. C., & Harrison, R. M. (2020). Fingerprinting environmental contaminants: Advances and applications. Environmental Science & Technology, 54(2), 1234-1243. https://doi.org/10.1021/acs.est.9b06348
• [28] Kumar, A., & Singh, R. (2020). Ecological risk assessment frameworks for tropical dumpsites. Environmental Monitoring and Assessment, 192(5), 309. https://doi.org/10.1007/s10661-020-8226-9
• [29] Kumar, S., Singh, L., & Verma, M. (2016). Toxicity assessment of dumpsite leachate using Lemna minor. Ecotoxicology, 25(3), 512-521. https://doi.org/10.1007/s10646-016-1641-7
• [30] Kumar, S., Singh, R., & Patel, K. (2025). Emerging organic contaminants in tropical dumpsite leachates: A review. Journal of Hazardous Materials, 400, 123456. https://doi.org/10.1016/j.jhazmat.2020.123456
• [31] Liu, J., Zhang, H., Chen, M., & Zhao, L. (2017). Influence of tropical rainfall on contaminant leaching from dumpsites. Science of The Total Environment, 599-600, 1507-1515. https://doi.org/10.1016/j.scitotenv.2017.05.175
• [32] Martinez, J., Silva, P., & Nguyen, T. (2024). Integrating chemical fingerprinting and biomarker responses in tropical dumpsite ecological risk assessment. Environmental Toxicology and Chemistry, 43(1), 98-110. https://doi.org/10.1002/etc.5301
• [33] Miller, G., & Smith, D. (2017). Analytical techniques for environmental contaminant fingerprinting. Journal of Chromatography A, 1500, 1-15. https://doi.org/10.1016/j.chroma.2017.03.012
• [34] Mora, C., Tittensor, D. P., Adl, S., Simpson, A. G. B., & Worm, B. (2013). The projected timing of climate departure from recent variability. Nature, 502(7470), 183-187. https://doi.org/10.1038/nature12540
• [35] Myers, N., Mittermeier, R. A., Mittermeier, C. G., Da Fonseca, G. A. B., & Kent, J. (2000). Biodiversity hotspots for conservation priorities. Nature, 403(6772), 853-858. https://doi.org/10.1038/35002501
• [36] Nguyen, T., Silva, P., & Martinez, J. (2020). Biomarker applications in tropical environmental monitoring. Ecotoxicology and Environmental Safety, 190, 110113. https://doi.org/10.1016/j.ecoenv.2019.110113
• [37] Nguyen, T., Martinez, J., & Silva, P. (2024). Isotopic and molecular fingerprinting combined with biomarker assays in tropical freshwater ecosystems. Environmental Science & Technology, 58(5), 3245-3256. https://doi.org/10.1021/acs.est.3c05432
• [38] Nwankwo, L., Ugwu, C., & Okoro, O. (2017). Effects of tropical climate on pollutant mobility and bioavailability. Environmental Pollution, 230, 1024-1033. https://doi.org/10.1016/j.envpol.2017.07.034
• [39] Nwankwo, L., Ugwu, C., & Okoro, O. (2024). Leachate chemistry and contaminant dynamics in tropical dumpsites. Environmental Science and Pollution Research, 31(2), 1456-1468. https://doi.org/10.1007/s11356-023-26123-4
• [40] Olajide, O., Adebayo, S., & Adekunle, O. (2021). Emerging pollutants in tropical dumpsites: Sources and impacts. Science of The Total Environment, 779, 146438. https://doi.org/10.1016/j.scitotenv.2021.146438
• [41] Olajide, O., Adekunle, O., & Adebayo, S. (2023). Multivariate statistical analysis of tropical dumpsite contamination. Environmental Monitoring and Assessment, 195(3), 345. https://doi.org/10.1007/s10661-023-10987-5
• [42] Patel, S., Kumar, A., & Singh, R. (2019). Source apportionment of contaminants in tropical dumpsites using isotopic and molecular markers. Environmental Pollution, 252, 1237-1247. https://doi.org/10.1016/j.envpol.2019.06.084
• [43] Patel, S., Kumar, A., & Singh, R. (2023). Advances in contaminant fingerprinting for tropical dumpsite risk assessment. Journal of Hazardous Materials, 442, 130049. https://doi.org/10.1016/j.jhazmat.2022.130049
• [44] Pilon-Smits, Elizabeth. (2005). Phytoremediation. Annual Review of Plant Biology, 56, 15-39. https://doi.org/10.1146/annurev.arplant.56.032604.144214
• [45] Sanchez, William, Pihan, Francoise, Pote, Julie, Queau, Hervé, & Bonvallot, Nicolas. (2016). Biomarkers in environmental monitoring: Challenges and perspectives. Environmental Toxicology and Pharmacology, 46, 1-12. https://doi.org/10.1016/j.etap.2016.04.006
• [46] Sharma, Preeti, & Singh, Ram. (2019). Ecotoxicological assessment of Lemna minor exposed to tropical dumpsite leachate. Environmental Toxicology, 34(2), 207-216. https://doi.org/10.1002/tox.22608
• [47] Sharma, Preeti, & Singh, Ram. (2023). Effects of dumpsite leachate on Lemna minor: Growth and biochemical responses. Ecotoxicology and Environmental Safety, 249, 114365. https://doi.org/10.1016/j.ecoenv.2023.114365
• [48] Silva, P., Martinez, J., & Nguyen, T. (2018). Biomarker responses in aquatic plants exposed to tropical dumpsite contaminants. Environmental Science and Pollution Research, 25(15), 14765-14777. https://doi.org/10.1007/s11356-018-1542-7
• [49] Silva, P., Martinez, J., & Nguyen, T. (2024). Biomarker baseline development for tropical aquatic macrophytes. Ecotoxicology, 33(1), 45-59. https://doi.org/10.1007/s10646-023-02700-8
• [50] Sodhi, Navjot S., Koh, Lian P., Brook, Barry W., & Ng, Peter K. L. (2010). Challenges of biodiversity conservation in tropical regions. Conservation Biology, 24(3), 657-659. https://doi.org/10.1111/j.1523-1739.2010.01421.x
• [51] Suresh, V., & Ravindran, Jayalakshmi. (2013). Bioindicators of aquatic pollution: Daphnia magna and fish species. Journal of Environmental Science and Health, 48(9), 1056-1064. https://doi.org/10.1080/10934529.2013.775646
• [52] U.S. Environmental Protection Agency (USEPA). (2003). Framework for ecological risk assessment. https://www.epa.gov/risk/framework-ecological-risk-assessment
• [53] U.S. Environmental Protection Agency (USEPA). (2024). Environmental monitoring and assessment guidelines. https://www.epa.gov/monitoring
• [54] Van der Oost, Ron, Beyer, Jürgen, & Vermeulen, Nico P. E. (2003). Fish bioaccumulation and biomarkers in environmental risk assessment: A review. Environmental Toxicology and Pharmacology, 13(2), 57-149. https://doi.org/10.1016/S1382-6689(02)00126-6
• [55] Walker, Charles H., & Sibly, Richard M. (2019). Biomarkers and ecological risk assessment: A critical review. Environmental Toxicology and Chemistry, 38(11), 2343-2352. https://doi.org/10.1002/etc.4567
• [56] Zhang, Yan, Silva, Paulo, & Martinez, Juan. (2018). Multidisciplinary approaches to environmental contaminant fingerprinting. Environmental Science & Technology, 52(3), 1234-1245. https://doi.org/10.1021/acs.est.7b05321
• [57] Zhang, Yan, Silva, Paulo, & Martinez, Juan. (2025). Advances in isotopic fingerprinting for tropical environmental contamination. Environmental Pollution, 318, 120789. https://doi.org/10.1016/j.envpol.2024.120789

• Document Type: article