Iranian Journal of

Background and Objective: Antibiotics are a group of emerging contaminants in the aquatic environment. Antibiotic residues threaten the human health and ecosystem in the low concentrations found in the environment. Hence, the present work has been conducted to investigate the occurrence and removal efficiency of most prescribed antibiotics including amoxicillin, penicillin, cefixime, cephalexin, ciprofloxacin, erythromycin and azithromycin detected in two urban wastewater treatment plants (WWTPs) in Tehran.
Materials and Methods: The present work is an applied research based on USEPA method no. 1694, to investigate pharmaceuticals residues in water by HPLC/MS/MS in year 2016. The differences between target antibiotics residues were investigated statistically. After the calculation of the removal efficiencies, the normality of the data was assessed. Then, parametric and non-parametric tests were used to compare the removal efficiencies in both WWTPs.
Results: There was not a significant difference between the influent and effluent concentrations of cefixime and azithromycin (in Ekbatan WWTP) and cefixime (in southern Tehran WWTP). There is a significant difference between the removal efficiencies of cephalexin (p=0.005) and erythromycin (p=0.002) in two WWTPs. The Highest median removal efficiencies were observed for cephalexin 94.41 and 99.47 in Ekbatan WWTP and southern Tehran WWTP, respectively.
Conclusion: In addition to the type of treatment processes, it is physicochemical properties of the selected compound has a significant influence on removal efficiencies.
 

Background and Objective: Occurrence of the pharmaceutical active residues (particularly antibiotics) threatens the health of the environment and human society. Therefore, this research aimed to investigate the impacts of the Amoxicillin (AMX) residues on resistance to environmental stress and biochemical compositions of the body in Penaeus vannamei.
Materials and Methods: Six-hundred specimens with a mean (±SD) weight and total length of 9.23±1.77 g and 9.28±0.73 cm were randomly experimented in four triplicate treatments, namely T₁(control): without AMX residues in a rearing environment, T₂: 100 μg/L AMX residues concentration in water, T₃: 300 μg/L and T₄: 500 μg/L for 60 days. At the end of the experimental trial, five specimens for biochemical body composition analyses were separately sampled. Ten shrimps from each treatment were also randomly selected and exposed to 50 ppt salinity stress for 48 hours, and then survival rates were computed.
Results: Body composition analyses showed that moisture and protein not differed among the treatments (p>0.05), while fat in T₂ (28.29±5.50) was significantly more than in others (p<0.05). The lowest values of ash were obtained in T₁ and T₄, and they differed with T₂ and T₃ (p<0.05). The highest survival rate of shrimps exposed to salinity stress (50 ppt in 48 h) was observed in T₂ and T₃, in contrast, the lowest value was recorded for T₄ (p<0.01).
Conclusion: Findings of the present research indicate that the occurrence of high doses of AMX residues pollution in the rearing water affects the stress resistance of P. vannamei which can be due to disruption of protein and fat metabolisms in the shrimp body.
 

Background and Objective: Vacuum Ultraviolet (VUV)-based advanced oxidation is a new category of advanced purification processes, so this study aimed to compare the efficiency of VUV and Ultraviolet-C (UVC) processes in combination with H₂O₂ and PMS in degrading Remdesivir.
Materials and Methods: The photoreactor was investigated with VUV and UVC lamps in combination with H₂O₂ and PMS for Remdesivir degradation. Also, the effect of variables such as solution pH, H₂O₂ dose, Remdesivir concentration, the presence of radical scavengers and anions, as well as hydraulic retention time was considered in the continuous process of Remdesivir removal.
Results: The findings showed that the optimal pH in the processes of VUV, UVC, and their derivatives was equal to 7. By adding 1 mM of PMS and H₂O₂ to the VUV process, the degradation efficiency of Remdesivir was increased from 92.2 ± 0.4% to 98.3 ±2.1% and 100 ± 0.3%, respectively, after 30 min. Also, in the UVC process combined with H₂O₂ and PMS, the degradation efficiency reached 77.8 ± 1.5 and 85.2 ± 1.3% after 40 min, respectively. The degradation kinetics in the examined processes were as follows: VUV/H₂O₂ > VUV/PMS > VUV > UVC/H₂O₂ > UVC/PMS > UVC. The hydroxyl radical was the main reactive oxygen species that led to the decomposition of Remdesivir. The continuous operation of VUV/H₂O₂ showed that the removal efficiency of Remdesivir reached 94.7 ±0.8% after 40 min.
Conclusion: Considering the high rate of Remdesivir degradation by adding H₂O₂, the VUV/H₂O₂ process can be introduced as an efficient technology for the removal of antiviral drugs.