Indirect electrochemical degradation of acetaminophen: process performance, pollutant transformation, and matrix effects evaluation

Acetaminophen (ACE), a highly consumed pharmaceutical, was degraded in aqueous matrices by reactive chlorine species (RCS) electrogenerated using Ti/IrO2 electrodes. Although this pollutant has been extensively treated by electrochemical techniques, little information is known about its degradation in fresh urine by electrogenerated RCS, and the understanding of its transformations using analyses of atomic charge. In this work, these two topics were discussed. Initially, the effect of current (10-40 mA) and supporting electrolyte (considering typical ions present in surface water and urine (Cl- and SO42-)) on the electrochemical system was evaluated. Then, the kinetics and primary transformations products involved in the elimination of ACE were described. It was found that, in distilled water, the process at 40 mA in NaCl presence led to 100 % of ACE degradation (10 min, 0.056 Ah L-1). Theoretical analyses of atomic charge for ACE indicated that the amide group is the most susceptible to attacks by RCS such as HOCl. On the other hand, degradation of acetaminophen in synthetic fresh urine was slower (21% of degradation after 60 min of treatment) than in distilled water. This was attributed to the other substances in the urine matrix, which induce competition for the degrading RCS.

Use of CdS from Teaching-Laboratory Wastes as a Photocatalyst for the Degradation of Fluoroquinolone Antibiotics in Water

Laboratory wastes containing Cd2+ and water polluted by pharmaceuticals represent an environmental concern. In this work, a proof concept, consisting of the use of teaching-laboratory wastes to synthesize CdS and its subsequent use as a photocatalyst to degrade fluoroquinolone antibiotics, was developed. The CdS was prepared by extraction with thioacetamide and calcination (at 450 °C) and characterized using several techniques. The photocatalytic activity of the CdS, to degrade levofloxacin and norfloxacin, was tested, and the routes involved in the process and the primary transformations of the fluoroquinolones were established. Moreover, the ability of CdS-photocatalysis to eliminate levofloxacin in simulated matrices of fresh urine and hospital wastewater was evaluated. The characterization analyses indicated that the CdS semiconductor was synthesized successfully. Effectively, the CdS acted as a photocatalyst toward degradation of levofloxacin, involving the action of superoxide anion radical, holes, and singlet oxygen mainly. The process induced transformations on the methyl-piperazyl moiety, plus hydroxylation of the fluoroquinolone nucleus on levofloxacin. Additionally, CdS-photocatalysis was highly selective for the elimination of the target pollutant in both tested matrices. Our research indicated the good potentiality of recycling teaching-laboratory wastes to generate photocatalysts to degrade organic pollutants. This work was presented at 4° Congreso Colombiano de Procesos Avanzados de Oxidación (4CCPAOx).

Field assessment in Cameroon of a reader of POC-CCA lateral flow strips for the quantification of Schistosoma mansoni circulating cathodic antigen in urine

Background Determining Schistosoma mansoni infection rate and intensity is challenging due to the low sensitivity of the Kato-Katz (KK) test that underestimates the true disease prevalence. Circulating cathodic antigen (CCA) excreted in urine is constantly produced by adult worms and has been used as the basis of a simple, non-invasive point of care test (POC-CCA) for Schistosoma mansoni infections. Although the abundance of CCA in urine is proportional to worm burden, the POC-CCA test is marketed as a qualitative test, making it difficult to investigate the wide range of infection intensities. This study was designed to compare the prevalence and intensity of S. mansoni by KK and POC-CCA and quantify, on fresh and frozen (<-20°C) urine samples, CCA using the visual scores and the ESEquant LR3 reader. Methodology Stool and urine samples were collected from 759 school-aged children. The prevalence and intensity of S. mansoni were determined using KK and POC-CCA. The degree of the positivity of POC-CCA was estimated by quantifying CCA on fresh and frozen urine samples using visual scores and strip reader. The prevalence, the infection intensity as well the relative amounts of CCA were compared. Results The S. mansoni infection rates inferred from POC-CCA and KK were 40.7% and 9.4% respectively. Good correlations were observed between infection intensities recorded by; i) the reader and visual scoring system on fresh (Rho = 0.89) and frozen samples (Rho = 0.97), ii) the reader on fresh urine samples and KK (epg) (Rho = 0.44). Nevertheless, 238 POC-CCA positive children were negative for KK, and sixteen of them had high levels of CCA. The correlation between results from the reader on fresh and frozen samples was good (Rho = 0.85). On frozen samples, CCA was not detected in 55 samples that were positive in fresh urine samples. Conclusion This study confirmed the low sensitivity of KK and the high capacity of POC-CCA to provide reliable data on the prevalence and intensity of S. mansoni infections. The lateral flow reader enabled accurate quantification of CCA under field conditions on fresh and frozen urine samples with less time and effort than KK.

Reliability of Three Urine Specific Gravity Meters Measuring Brix and Urine Solutions at Different Temperatures

Context: The measurement of urine specific gravity should be performed at room temperature (20 °C) but sample temperature is not always taken in consideration. Objective: Evaluate the effect of sample temperature on the measurement accuracy of a digital (DIG) and optical (MAN) refractometer and a hydrometer (HYD). Design: Quantitative comparison between measurement outcomes for a reference solution (sucrose, degrees Brix) and fresh collected urine samples. Samples: Experiment 1 used a 24 Brix (°Bx) samples and experiment 2 used 33 fresh urine samples. Main Outcome Measure: Urine specific gravity (USG). Results: Experiment 1 showed DIG and MAN did not differ from reference, but HYD reported lower or inconsistent values compared to Bx, while highly correlating with Bx solutions (r: &gt; 0.89). The overall diagnostic ability of elevated USG (≥ 1.020; ≥ 1.025; ≥ 1.030) was high for all tools (AUC &gt; 0.92). Misclassification of samples increased from 0 to 2 at 1.020 to 1 to 3 samples at cutoff 1.025 and 1.030 USG. Bland–Altman analysis showed DIG 5 °C underreports slightly without reporting bias (r: −0.344, P = 0.13); all other plots for DIG, MAN, and HYD showed considerably larger underreporting at higher concentrations (r ranging from −0.21 to −0.97 with P &gt; .02) at all temperatures. The outcomes of experiment 2 using DIG 20°C as standard, showed only negligible differences between DIG and MAN at all temperatures, but larger differences using HYD. Conclusions: All tools showed reporting bias when compared to °Bx solutions which can impact classification of low and high urine concentration at higher USG cutoff values, especially at a sample temperature of 37 °C.

Alkaline Dehydration of Human Urine Collected in Source-Separated Sanitation Systems Using Magnesium Oxide

Fresh human urine, after it is alkalized to prevent the enzymatic hydrolysis of urea, can be dehydrated to reduce its volume and to produce a solid fertilizer. In this study, we investigated the suitability of MgO to alkalize and dehydrate urine. We selected MgO due to its low solubility (&lt;2 g·L−1) and relatively high saturation pH (9.9 ± 0.2) in urine. Using a laboratory-scale setup, we dehydrated urine added to pure MgO and MgO mixed with co-substrates (biochar, wheat bran, or calcium hydroxide) at a temperature of 50°C. We found that, dehydrating urine added to a mixture of MgO (25% w/w), biochar, and wheat bran resulted in a mass reduction of &gt;90% and N recovery of 80%, and yielded products with high concentrations of macronutrients (7.8% N, 0.7% P and 3.9% K). By modeling the chemical speciation in urine, we also showed that ammonia stripping rather than urea hydrolysis limited the N recovery, since the urine used in our study was partially hydrolyzed. To maximize the recovery of N during alkaline urine dehydration using MgO, we recommend treating fresh/un-hydrolysed urine a temperature &lt;40°C, tailoring the drying substrate to capture NH4+ as struvite, and using co-substrates to limit the molecular diffusion of ammonia. Treating fresh urine by alkaline dehydration requires only 3.6 kg MgO cap−1y−1 and a cost of US$ 1.1 cap−1y−1. Therefore, the use of sparingly soluble alkaline compounds like MgO in urine-diverting sanitation systems holds much promise.

Usefulness Of Medi Test Combi 9 In The Diagnosis Of Hemoglobinuria In Limited Recourse Setting

Detection of hemoglobin in fresh urine remains a challenge in resource limited setting since quantitative measurements of hemoglobinuria is not always technically feasible. This study aimed to evaluate the performance of 3 types of dipstick for the diagnosis of hemoglobinuria in children suffering Black water fever.

NephroCheck® Quality Test

<b><i>Background:</i></b> The acute kidney injury (AKI) risk score helps detect moderate and severe AKI in the next 12–24 h. However, inappropriate urine collection may impact its results. <b><i>Aim:</i></b> The aim of this study was to evaluate the stability of NephroCheck® after urine storage at different temperatures. <b><i>Methods:</i></b> The urine sample was centrifuged and split into 3 tubes. One was tested as soon as possible by the laboratory. The other 2 samples were frozen at −20 and −80°C, and the NephroCheck® test was performed 8 weeks later. <b><i>Results:</i></b> The mean values of the AKI risk score were 1.19 ± 0.93, 1.15 ± 1.14, and 1.20 ± 1.11 (ng/mL)²/1,000 for fresh urine, −20, and −80°C, respectively (<i>p</i> = 0.70). Spearman’s rank correlation for −20 and −80°C versus immediate processing was strong with a rho of 0.82 and 0.98, respectively. <b><i>Conclusion:</i></b> The AKI risk score was relatively stable. Urine could be collected without dry ice or liquid nitrogen and kept for up to 8 weeks with either −20 or −80°C freezing with stable NephroCheck® results.

Degradation of Losartan in Fresh Urine by Sonochemical and Photochemical Advanced Oxidation Processes

In this work, the degradation of the pharmaceutical losartan, in simulated fresh urine (which was considered because urine is the main excretion route for this compound) by sonochemistry and UVC/H2O2 individually, was studied. Initially, special attention was paid to the degrading action of the processes. Then, theoretical analyses on Fukui function indices, to determine electron-rich regions on the pharmaceutical susceptible to attacks by the hydroxyl radical, were performed. Afterward, the ability of the processes to mineralize losartan and remove the phyto-toxicity was tested. It was found that in the sonochemical treatment, hydroxyl radicals played the main degrading role. In turn, in UVC/H2O2, both the light and hydroxyl radical eliminated the target contaminant. The sonochemical system showed the lowest interference for the elimination of losartan in the fresh urine. It was established that atoms in the imidazole of the contaminant were the moieties most prone to primary transformations by radicals. This was coincident with the initial degradation products coming from the processes action. Although both processes exhibited low mineralizing ability toward losartan, the sonochemical treatment converted losartan into nonphytotoxic products. This research presents relevant results on the elimination of a representative pharmaceutical in fresh urine by two advanced oxidation processes.

Selective Oxidation of Pharmaceuticals and Suppression of Perchlorate Formation during Electrolysis of Fresh Human Urine

<p>Many pharmaceutical compounds are excreted unchanged or as active metabolites via urine. They pass through conventional wastewater treatment processes and present a risk to aquatic ecosystems and humans. Point-source remediation of source-separated urine provides a promising alternative to destroy pharmaceuticals before dilution with wastewater. Electrochemical advanced oxidation processes are one possible option for degrading pharmaceuticals in urine, but they often lead to the formation of oxidation byproducts (OBPs) including chlorate, perchlorate, and halogenated organics at hazardous concentrations due to high background chloride concentrations. Here, we show that the high urea content of fresh human urine suppresses the formation of oxychlorides by inhibiting formation of HOCl/OCl‒ during electrolysis, while still enabling the oxidation of pharmaceuticals by •OH due to the slow rate of urea oxidation by •OH. This results in improved performance when compared to equivalent treatment of hydrolyzed aged urine. This (primarily indirect) electrochemical oxidation scheme is shown to degrade the model pharmaceuticals cyclophosphamide and sulfamethoxazole with surface-area-to-volume-normalized pseudo-first-order observed rate constants greater than 0.08 cm/min in authentic fresh human urine matrixes. It results in two orders-of-magnitude decrease in pharmaceutical concentrations in 2 hours while generating three orders-of-magnitude lower oxychloride byproduct concentrations in synthetic fresh urine as compared to synthetic hydrolyzed aged urine matrixes. Importantly, this proof-of-principle shows that simple and safe electrochemical methods can be used for point-source-remediation of pharmaceuticals in fresh human urine (before storage and hydrolysis), without formation of significant oxychloride byproducts. <br></p>