Jawaria Abid

This study investigated the potential of microbial-assisted phytoremediation using Eichhornia crassipes (water hyacinth) to reduce heavy metal and salinity pollution in produced water collected from Aadi Oil Field in Gujar Khan, Pakistan. Produced water was analyzed for physicochemical parameters and heavy metal content using Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES) to establish baseline data. E. crassipes plants augmented with indigenous, contaminant-tolerant microbial isolates were employed in a 15-day laboratory experiment. The results showed a resilient growth response, with plant height increasing to approximately 11–15 cm and root length extending up to 10–13 cm across treatments. Biomass also improved, with wet weights reaching 21–24 g from an initial 20 g. The treatment effectively reduced key physicochemical parameters: pH was stabilized from an initial alkaline value of 9.14 to near-neutral values (7.0–7.5), and total dissolved solids (TDSs) were reduced by approximately 50%. Heavy metal removal rates varied, with the highest efficiency of 79.2% for Silver (Ag) and the lowest (18.5%) for Mercury (Hg) This study demonstrates that E. crassipes actively participated in phytoremediation by absorbing and accumulating heavy metals and reducing salinity. The association with contaminant-tolerant microbes appeared to enhance the plant’s tolerance and overall treatment efficacy, indicating that plant–microbe interactions offer a sustainable strategy for the treatment of produced water.

The widespread presence of pharmaceutical residues, particularly emerging antibiotics such as levofloxacin (LVX) and amoxicillin (AMOX), in aquatic environments poses serious risks to ecosystems and public health. In this study, magnetically modified biochar was synthesized from orange peel waste and evaluated for the percentage removal of LVX and AMOX from synthetic wastewater. The biochar was chemically modified with iron to enhance its adsorption capacity and facilitate magnetic separation. The physicochemical properties of raw and iron-modified biochar were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Batch adsorption experiments were conducted to investigate the effects of temperature, contact time, adsorbent dosage, pH, and initial antibiotic concentration on removal efficiency. Antibiotic concentrations were quantified using UV–Vis spectrophotometry. Batch adsorption experiments revealed that iron-modified biochar (FeMBC) significantly outperformed raw biochar (RBC) in antibiotic removal. Optimal removal efficiencies of 90% for AMOX and 92% for LVX were achieved at an adsorbent dosage of 0.1 g, antibiotic concentration of 10 mg L⁻¹, contact time of 120 min, and temperature of 30 °C. Equilibrium data were best described by the Langmuir isotherm model, indicating monolayer adsorption, with correlation coefficients of 0.98 for AMOX and 0.97 for LVX. Kinetic analysis showed that the pseudo-second-order model provided the best fit, suggesting that chemisorption dominated the adsorption process. Thermodynamic studies confirmed that the adsorption was spontaneous and exothermic. Overall, the results demonstrate that iron-modified orange peel biochar is an efficient (90% better removal efficiency than RBC), low-cost, and environmentally sustainable adsorbent for the removal of emerging antibiotics from pharmaceutical wastewater, offering strong potential for practical water treatment applications.

Laboratory uptake and depuration kinetics of ¹³⁷Cs were determined in freshwater green filamentous algae Spirogyra sp. and macrophyte Hydrilla verticillata by using the radiotracer technique. This study provides the first comprehensive comparative analysis of two distinct groups of freshwater plant, free floating algae and a submerged vascular plant, that accumulate radioactive ¹³⁷Cs over time. The results showed that both plants take up ¹³⁷Cs from water in direct proportion to its dissolved concentration during the experiment. At equilibrium, the concentration factors were found to be 4.80 ± 0.03 (mL g⁻¹) and 3.15 ± 0.06 (mL g⁻¹) while uptake rate constant k_u was 0.58 ± 0.09 (d⁻¹) and 0.21 ± 0.04 (d⁻¹) for Spirogyra sp. and H. verticillata, respectively. Depuration kinetic parameters indicated that most of the radiocesium was rapidly lost from plants during the first days of depuration, and only 20–40% of ¹³⁷Cs was retained in both plants at the end of the experiment. The depuration rate constants (k_e) and the biological half-lives (T_b1/2) of ¹³⁷Cs were observed to be 0.16 ± 0.01 (d⁻¹) and 0.09 ± 0.08 (d⁻¹) and 4.29 ± 0.01(d⁻¹) and 7.70 ± 0.04 (d⁻¹) for Spirogyra sp. and H. verticillata, respectively. Differences in ¹³⁷Cs concentration between both species growing under similar environmental conditions suggest that the uptake rate of ¹³⁷Cs is mainly influenced by plant morphology. The results presented in this study suggest that both Spirogyra sp. and H. verticillata could serve as suitable bioindicators for monitoring ¹³⁷Cs contamination in freshwater systems.

The widespread discharge of synthetic dyes such as Eriochrome Black T (EBT) into water bodies poses significant environmental and health concerns due to their toxicity, persistence, and resistance to degradation. In response to this issue, the removal of EBT dye from aqueous solutions using nickel-modified orange peel biochar (MOPB) was investigated in this study at various experimental conditions such as adsorbent dose, pH, concentration of dye, temperature, and contact time. Biochar was prepared from orange peels via pyrolysis, and structural characterization was performed using FTIR, XRD, and SEM to assess morphological changes, pore structure, and functional groups post-modification. MOPB exhibited significantly enhanced adsorption capacity compared to unmodified biochar. Optimal removal (at 0.1 g adsorbent dose, 25 ppm dye concentration, 90 min contact time, 35 °C, and pH 4) resulted in maximum EBT elimination. The equilibrium dataset was evaluated using Langmuir and Freundlich isotherm models. The Langmuir model (R² = 0.99) best described the uptake of EBT dye, which implies that the adsorption of EBT dye onto MOPB was monolayered. The kinetic data were also analyzed using pseudo-first-order and pseudo-second-order models. The pseudo-second-order kinetic model was found to be the best fit (R² = 0.99), indicating that it governs the rate-limiting step of the reaction. Thermodynamic parameters confirmed that the adsorption process is spontaneous and exothermic. These findings demonstrate the potential of MOPB as a low-cost, sustainable adsorbent for the efficient removal of EBT from industrial wastewater.

Twenty surface sediment samples were gathered from Chasma Lake, deciding the radionuclides ¹³⁷Cs, ²²⁶Ra, ²²⁸Ra, ²³²Th, and ⁴⁰K and their associated hazard indices. The deliberate radionuclide activities of present research have been contrasted with earlier research, and acquired outcomes in the present study are found below the results in the world. The radiation hazard indices following the presence of natural radionuclides in sediment samples were estimated, and the results assigned the values of all the determined radiological indices found inside the worldwide suggested limits. It was concluded from the current review that the sediment of Chashma Lake is safe for construction and agriculture and does not make radiation dangerous to the nearby local area of the lake.