Skip to main content
Search for Articles:
Tropical Aquatic and Soil Pollution

Trop. Aqua. Soil Pollut. , Vol. 4 Iss. 1 (2024) – 5 articles

			View Vol. 4 Iss. 1 (2024)
Published: 6 February 2024
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published. To view the papers in pdf format, click on the "View PDF Full-text" link.

Stabilization of Pb, Cu, and Zn in Phytoaccumulator Ash in Calcined Clay-based Geopolymers and Potential Application
by Samuel Sunday Ogunsola, Adedeji Adebukola Adelodun, Mary Bosede Ogundiran

Trop. Aqua. Soil Pollut. 2024, 4(1), pp 27-42;

Following phytoremediation, the disposal of accumulating plants (phytoaccumulators) is challenging because the accumulated metals could leach back into the soil if not properly managed. Therefore, this study aims to use calcined clay (CC)-based geopolymer to stabilize Pb, Cu, and Zn in a phytoaccumulator (Sporobolus pyramidalis) ash (PA). Additionally, the effect of adding PA on the setting time, mechanical and heavy metals leaching properties of the geopolymers was investigated, to determine their environmental suitability and potential applications. Mixed proportions of CC (85-100%) and PA (5% - 15%) were used to produce geopolymers, using 8 M NaOH/Na2SiO3 (1:1) as an alkaline activator. The geopolymers were cured for 7 and 28 days at ambient temperatures. Thermograms showed the dehydroxylation of kaolinite at 450-650 °C. X-ray flourescene (XRF) analysis showed CC’s predominant oxides as SiO2 (53.1%) and Al2O3 (41.4%), while PA exhibited SiO2 (46.6%), CaO (13.8%), PbO (1.30%), ZnO (0.28%), and CuO (0.04%). Thermal treatment eliminated most FTIR bands associated with kaolinite, converting crystalline kaolinite into amorphous metakaolinite. Geopolymer setting time ranged from 75 min (100% CC) to 111 min (85% CC). Furthermore, elevated Cao content in the PA resulted in the geopolymer’s early strength development. However, the compressive strength decreased as PA quantity increased, with 95% CC-PA exhibiting maximum strength (22.5 ± 0.2 MPa) after 28 days. Further tests confirmed that 95% and 90% CC-PA geopolymer effectively stabilized Pb and Cu. Fabricated geopolymers met the ASTM (C62-17) Specification Standard for building brick, indicating their suitability as a waste-based construction material under controlled conditions. Full text

Phytoremediation with Sunflower (Helionthus annus) and Its Capacity for Cadmium Removal in Contaminated Soils
by Peter Oyelade Ogungbile, Adefemi Olatayo Ajibare, Adebisi Esther Enochoghene, Timothy Oyebamiji Ogunbode, Olumide Ekundayo Omotayo Omotayo, Christiana Tinuola Ekanade, Mynepalli Kameswara Chandra Sridhar, John Adebayo Akande

Trop. Aqua. Soil Pollut. 2024, 4(1), pp 1-9;

This study assessed the phytoremediation potential of sunflowers for removing cadmium from the soil around a paint manufacturing industry in Eleyele, Ibadan. Background levels of Cd in the topsoil and subsoil were determined. The site was divided into two plots. Organo-mineral fertilizer (OMF) was applied to the first plot, which served as the experimental plot, while the second plot was without OMF and served as the control. Concentrations of cadmium in the plants were determined using an Atomic Absorption Spectrophotometer. Baseline mean Cd contents were 29.23 mg/kg and 33.30 mg/kg for topsoil and subsoil, respectively. Over the planting period, the sunflower plants removed 53.1% and 51.6% of Cd from the topsoil and subsoil in the test plot, while 40.65% and 47.80% were removed from the topsoil and subsoil, respectively, in the control. Cd absorption from the contaminated soils was found to be translocated to all parts of the sunflower. The concentrations of Cd in the sunflower parts were as follows: root system (10.70 mg/kg), shoot (8.17 mg/kg), leaves (6.43 mg/kg), and seeds (2.52 mg/kg) for the test plot. For the control plots, Cd in the root, shoot, leaves, and seeds were 7.60 mg/kg, 7.43 mg/kg, 4.75 mg/kg, and 2.03 mg/kg, respectively. The study confirmed that sunflowers have the potential to remediate Cd from contaminated soil, and this potential was enhanced by the application of OMF. Full text

Assessing the Impact of Pharmaceutical Contamination in Malaysian Groundwater: Risks, Modelling, and Remediation Strategies
by Michael Lie, Rubiyatno, Faisal Saud Binhudayb, Nguyen Thi Thanh Thao, Risky Ayu Kristanti

Trop. Aqua. Soil Pollut. 2024, 4(1), pp 43-59;

Pharmaceuticals in Malaysia’s groundwater are a growing concern as they can potentially affect the environment and human health negatively. Pharmaceuticals are found in abundance in groundwater from sources such as septic tanks, leachates from landfills, wastewater effluents from pharmaceutical-related industries, medical institutions, wastewater treatment plants, and households, agriculture runoff and leakage of effluent wastes in Malaysia. Pharmaceutical contaminant usually travels through advection and dispersion from waterways or soil into the groundwater. The mathematical model of the advection-dispersion equation and enzyme-linked immunosorbent assay (ELISA) are analysed for the prediction of movement and concentration of pharmaceuticals.  Furthermore, the evolution of pharmaceuticals in the environment, living organisms and human health is assessed. Pharmaceuticals have found their way into the food chain and exhibit toxicity and hazard to aquatic ecosystems. However, the toxicity of pharmaceuticals to humans is still not yet much to be researched although strong evidence of possible negative consequences. Moreover, remediation technologies such as activated carbon adsorption, activated sludge, anaerobic treatment and advanced oxidation process are discussed for the mitigation of pharmaceuticals contamination. Full text

Microplastics and Antibiotics in Aquatic Environments: A Review of Their Interactions and Ecotoxicological Implications
by Kuok Ho Daniel Tang

Trop. Aqua. Soil Pollut. 2024, 4(1), pp 60-78;

Microplastics and antibiotics are two significant emerging pollutants found together in water bodies, raising concerns about their mutual effects. This review delves into how microplastics and antibiotics interact in aqueous environments and the ecotoxicological implications of such interactions, particularly the bioavailability of antibiotics and the prevalence of antibiotic-resistance genes. It outlines that antibiotics attach to microplastics primarily through hydrophobic, hydrogen-bonding, and electrostatic interactions. Other bonds, comprising halogen bonding, cation−π interaction, and negative charge-assisted hydrogen bonds, may also be involved to better explain antibiotic adsorption patterns. The adsorption of antibiotics to microplastics often follows the pseudo-second-order kinetic model and in some instances, the pseudo-first-order kinetic model. The common adsorption isotherms governing this interaction are the linear and Freundlich models. Microplastics may increase the biodegradation of adsorbed antibiotics due to the presence of antibiotic-degrading bacteria in the biofilms. They could also hamper direct photodegradation but facilitate indirect photodegradation of adsorbed antibiotics. However, their photodegradative effect remains inconclusive. Microplastics and antibiotics exhibit significant toxicity to algae, while their effects on fish and daphnia are less noticeable, suggesting that their combination does not pose an immediate threat to the well-being and proliferation of larger aquatic organisms. In some instances, microplastics reduce the deleterious effects of antibiotics on aquatic life. Microplastics serve as catalysts for gene transfer, enhancing the propagation of antibiotic-resistance genes in these ecosystems. This review underscores the importance of understanding the regulatory mechanisms of microplastics on antibiotic-resistance gene diversity, particularly at the gene expression level. Full text

Biodegradation of Chlorpyrifos by Microbes: A Review
by Rubiyatno, Aulia Maulana, Jovale Vincent Tongco, Arma Yulisa, Sang Hyeok Park, Md Abu Hanifa Jannat, Rega Permana, Ocean Thakali, Michael Lie, Aouatif Fahssi, Ouahiba Aziez, Camilo Bastidas

Trop. Aqua. Soil Pollut. 2024, 4(1), pp 10-26;

Chlorpyrifos (CP) is a widely used organophosphate pesticide known for its recalcitrant nature, raising concerns about potential ecological and health impacts due to its toxicity. Many plants and animals are contaminated with this pesticide. Microbial biodegradation offers an environmentally friendly and effective method to remove CP from the environment and mitigate its impacts, especially given its low cost, particularly when bioremediation is conducted on-site. Different types of microbial species have been found to function under various environmental conditions, with some, like Pseudomonas nitroreducens PS-2 and Pseudomonas aeruginosa (NCIM 2074), showing promising results with degradation rates of up to 100%. However, challenges exist, such as partial degradation caused by the presence of metabolites, and the recalcitrant nature of CP, which can impede microbes' ability to effectively degrade its hydrocarbon ring. Overall, a combination of approaches, such as microbial and algal methods, or the discovery of new microbial strains, can help overcome these challenges and further enhance the long-term viability of this technique. Full text