Waste water generated from vehicle service/wash centres are serious issue in now a day. This become critical if waste water from unauthorized service centres is discharged to the river stream which has potential to degrade river water quality and its depended wildlife. The present study demonstrates that the river water chemistry changes drastically and river become more worse after the influx of the discharged waste water from vehicle service/wash centres. Significant number of surfactants, oil & grease, nitrate and nitrite are detected in both the river water while they are passing through the Dehradun city stretch, Uttarakhand- India. Further, service centres are also the major contributor of the heavy metals in river water, however the concentration of Cu, Mn, Fe, Cu, Zn, As, Cd, Pb, and Ni under acceptable limits at upper stretch of the Rispana and Bindal. Whereas, the study reveals that the HPI value of the metals are > 30 at each location which indicates their unsuitability for utility. Moreover, HI values are estimated under unity which are 0.00845, 0.00655, 0.00542, 0.033 for upper stretch -Rispana, upper stretch-Bindal, average effluent discharge from vehicle service centres and downstream of river, respectively indicates less possible threat to non-carcinogenic effects. In upper stretch of both the rivers, cancer risk values of heavy metals such as As, Cr, and Ni are estimated under 1*10 -4 while other exceeds show the probability of cancer if consumed for long term. In best of our knowledge this is the first study, therefore no data is available to compare and observe the changes, if occur.Additionally, more studies are needed to understand and establish the relationship between contaminated river water quality and its impact on dependent wildlife.

Rice husk-derived biochars with progressively modified surface properties were investigated for adsorbing flucloxacillin sodium (FLX-Na) from aqueous solution. Four materials—rice husk biochar (RHB), nitrogen-functionalized RHB (N-RHB), magnetic nitrogen-functionalized RHB (MN-RHB), and magnetic nitrogen/sulfur-functionalized RHB (MN,S-RHB)—were prepared and characterised using morphological, structural, textural, and surface-chemical techniques. The sequential preparation routes produced materials with different surface areas, pore structures, and surface functionalities. FLX-Na adsorption increased in the order RHB < MN-RHB < N-RHB < MN, S-RHB, with the highest equilibrium adsorption capacity obtained for MN,S-RHB (118.6 mg g⁻¹). Because chemical activation and a higher carbonisation temperature were introduced only for MN,S-RHB, the higher uptake is interpreted as an effect of the combined modification route rather than being attributed specifically to N/S co-doping. Kinetic and equilibrium data were described using several empirical models, with the pseudo-second-order and Sips models giving the highest coefficients of determination among the tested fits. The adsorption capacity of MN,S-RHB decreased from 84.60 ± 1.30 mg g⁻¹ in deionised water to 60.30 ± 1.80 mg g⁻¹ in a mixed inorganic/humic-acid matrix, corresponding to 71.3% capacity retention. Spectroscopic changes after adsorption were consistent with changes in the surface chemical environment, while the matrix experiments indicated that coexisting inorganic ions and dissolved organic matter influenced adsorption performance. These results show that the combined physicochemical modification route altered the adsorption behaviour of rice husk-derived biochar under the investigated conditions.

Pharmaceutical contaminants, such as Cefuroxime sodium, pose a significant threat to aquatic ecosystems due to their persistence and bioactivity. This study reports the synthesis of sustainable mesoporous silica adsorbents, RH-MCM-41 and RH-SBA-15, from rice husk, an abundant agricultural waste, for efficient removal of cefuroxime from water. The adsorbents exhibited points of zero charge (pH_PZC) values of 5.2 and 4.5, respectively, which influenced surface interactions with anionic cefuroxime. Batch adsorption experiments revealed high removal efficiencies, while desorption studies demonstrated that acidic eluents, particularly nitric and phosphoric acids, regenerated over 90% of the adsorbed antibiotic. In the present study, under optimum conditions (pH 6.0, adsorbent dosage 0.05 g, contact time 120 min, and initial concentration 200 mg·L⁻¹), RH-SBA-15 exhibited a maximum Langmuir adsorption capacity of 105.4 mg·g⁻¹. At the same time, RH-MCM-41 showed 98.7 mg·g⁻¹, with high cefuroxime removal efficiencies under controlled batch conditions. Reusability tests confirmed structural stability and sustained adsorption over multiple cycles. Compared with conventional adsorbents, rice husk-derived mesoporous silica combines high adsorption performance, low-cost synthesis, and environmental sustainability. These findings highlight that the synthesised mesoporous silica materials demonstrated promising adsorption performance toward cefuroxime sodium in controlled single-component model solutions, indicating their potential applicability for future pharmaceutical wastewater remediation studies.