Assessment of nonsteroidal anti-inflammatory drugs by ultrasonic-assisted extraction and GC-MS in Mgeni and Msunduzi river sediments, KwaZulu-Natal, South Africa

Development of a GIS-based knowledge hub for contaminants of emerging concern in South African water resources using open-source software: Lessons learnt

With population growth and dwindling freshwater sources, protecting such sources has come to the forefront of water resource management. Historically, society's response to a problem is based on funding availability, current threat, and public outcry. Achieving this is largely dependent on the knowledge of the factors that are resulting in compromised water sources. These factors are constantly changing as novel contaminants are introduced into surface water sources. As we are in the information age, the interest in contaminants of emerging concern (CEC) is gaining ground. Whilst research is being conducted to identify contaminants in South African water sources, the research outputs and available information is not collated and presented to the science community and stakeholders in readily available formats and platforms. Current research outcomes need to be made known to regulators in order to develop environmental laws. By using fourth industrial revolution technology, we were able to collate available data in literature and display these in a user-friendly online format to regulatory bodies as well as researchers. A standardized excel spreadsheet was developed and uploaded to a PostgreSQL, running a PostGIS extension and was then processed in the GeoServer to allow for visualization on an interactive map which can be continuously updated. The near real-time access to information will reduce the possibility of duplication of research efforts, enhance collaboration in the discipline, and act as a CEC early warning system.

Pharmaceutical pollution of hospital effluents and municipal wastewaters of Eastern Canada

Quantification of drugs residues in wastewaters of different sources could help better understand contamination pathways, eventually leading to effluent regulation. However, limited data are available for hospital-derived wastewaters. Here, an analytical method based on automated on-line solid-phase extraction liquid chromatography tandem mass spectrometry (on-line SPE - UPLC-MS/MS) was developed for the quantification of multi-class pharmaceuticals in wastewaters. Filtrate phase and suspended solids (SPM) were both considered to evaluate the distribution of targeted analytes. Experimental design optimization involved testing different chromatographic columns, on-line SPE columns, and loading conditions for the filtrate phase, and different organic solvents and cleanup strategies for suspended solids. The selected methods were validated with suitable limits of detection, recovery, accuracy, and precision. A total of 30 hospital effluents and 6 wastewater treatment plants were sampled to evaluate concentrations in real field-collected samples. Certain pharmaceuticals were quantified at high levels such as caffeine at 670,000 ng/L in hospital wastewaters and hydroxyibuprofen at 49,000 ng/L in WWTP influents. SPM samples also had high contaminant concentrations such as ibuprofen at 31,000 ng/g in hospital effluents, fluoxetine at 529 ng/g in WWTP influents or clarithromycin at 295 ng/g in WWTP effluents. Distribution coefficients (K_d) and particle-associated fractions (Φ) indicate that pharmaceuticals tend to have better affinity to suspended solids in hospital wastewater than in municipal wastewaters. The results also bring arguments for at source treatment of these specific effluents before their introduction into urban wastewater systems.

Method optimisation and application based on solid phase extraction of non steroidal anti-inflammatory drugs, antiretroviral drugs, and a lipid regulator from coastal areas of Durban, South Africa

This study presents an optimized method that is applicable in monitoring the occurrence of pharmaceuticals in a wide range of aquatic environments. The optimised Solid Phase Extraction method is based on Bond Elut Plexa cartridges for the identification and quantification of three non-steroidal anti-inflammatory drugs, three antiretroviral drugs and a lipid regulator in the coastal area of Durban city, South Africa covering four seasons. The extracted compounds are qualitatively and quantitatively detected by a high-performance liquid phase chromatographic instrument coupled to a photodiode array detector. The recoveries range from 62 to 110% with a Relative Standard Deviation of 0.56−4.68%, respectively, for the determination of emtricitabine, tenofovir, naproxen, diclofenac, ibuprofen, efavirenz, and gemfibrozil. The analytical method is validated by spiking estuarine water samples with 5 µg L− 1 of a mixture containing the target pharmaceuticals and the matrix detection limit is established to be 0.62–1.78 µg L− 1 for the target compounds. The optimized method is applied to seasonal monitoring of pharmaceuticals at chosen study sites from winter and spring of 2019 and summer and autumn of 2020. The results indicate the concentration of the pharmaceuticals studied varies with the type of aquatic environment and season.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

Effect of Calcination Conditions on the Properties and Photoactivity of TiO2 Modified with Biuret

A simple wet impregnation-calcination method was used to obtain a series of novel non-metal doped TiO2 photocatalysts. Biuret was applied as C and N source, while raw titanium dioxide derived from sulfate technology process was used as TiO2 and S source. The influence of the modification with biuret and the effect of the atmosphere (air or argon) and temperature (500–800 °C) of calcination on the physicochemical properties and photocatalytic activity of the photocatalysts towards ketoprofen decomposition under simulated solar light was investigated. Moreover, selected photocatalysts were applied for ketoprofen photodecomposition under visible and UV irradiation. Crucial features affecting the photocatalytic activity were the anatase to rutile phase ratio, anatase crystallites size and non-metals content. The obtained photocatalysts revealed improved activity in the photocatalytic ketoprofen decomposition compared to the crude TiO2. The best photoactivity under all irradiation types exhibited the photocatalyst calcined in the air atmosphere at 600 °C, composed of 96.4% of anatase with 23 nm crystallites, and containing 0.11 wt% of C, 0.05 wt% of N and 0.77 wt% of S.

Occurrence and ecotoxicological risk assessment of non-steroidal anti-inflammatory drugs in South African aquatic environment: What is known and the missing information?

Non-steroidal anti-inflammatory drugs (NSAIDs) are medications used individually or as mixtures with other pharmaceuticals for the treatment of various illnesses. Their easy accessibility and high human consumption have resulted to their detection at high concentrations in South African water resources. In the present work, an extensive review of the occurrence and ecotoxicological risk assessment of NSAIDs in South African aquatic environment is provided. Reviewed literature suggested ibuprofen, naproxen, diclofenac, ketoprofen and fenoprofen as the most prominent NSAIDs in the South African aquatic environment. Among these NSAIDs, higher concentrations of ibuprofen are common in South African waters. As a result, this drug was found to pose high ecotoxicological risks towards the aquatic organisms with the highest risk quotients of 14.9 and 11.9 found for algae in surface water and wastewater, respectively. Like in other parts of the world, NSAIDs are not completely removed in wastewater treatment plants. Removal efficiencies below 0% due to higher concentrations of NSAIDs in wastewater effluents rather than influents were observed in certain instances. The detection of NSAIDs in sediments and aquatic plants could serve as the important starting step to investigate other means of NSAIDs removal from water. In conclusion, recommendations regarding future studies that could paint a clearer picture regarding the occurrence and ecotoxicological risks posed by NSAIDs in South African aquatic environment are provided.

Facile fabrication of magnetic covalent organic frameworks for magnetic solid-phase extraction of diclofenac sodium in milk

A robust magnetic solid-phase extraction (MSPE) method based on magnetic covalent organic framework (MCOF) coupled with high-performance liquid chromatography (HPLC)-ultraviolet (UV)/mass spectrometry (MS) was proposed for the determination of trace diclofenac sodium (DS) in milk. The prepared MCOF exhibited high extraction efficiency, which can be attributed to its high specific surface area as well as strong π-π and hydrophobic interactions between MCOF and DS. In addition, the potential influencing factors, including sample volume, adsorbent dosage, extraction time, and elution parameters, were fully estimated. The experimental results demonstrated that the established method was sensitive for the quantification of DS with high accuracy. Remarkably, the detection limit of DS was found to be 10 ng/kg under the optimal conditions. More impressively, the developed method was successfully applied to monitor trace DS in milk, demonstrating its outstanding durability and practical potential as an appealing method to regular monitor trace pharmaceutical contaminants in real food samples.

Quantification of selected pharmaceutical compounds in water using liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS)

The detection and quantitation of pharmaceutical compounds (PCs) in different environmental matrices is still a challenge, due to their extremely low (ng-μg) concentrations and the lack of rapid and sensitive analytical techniques. A number of techniques, such as enzyme-linked immunosorbent assay (ELISA), chromatography, electrophoresis, and electrochemical methods have been explored. These methods are limited by their poor sensitivity. In this study, a hyphenated liquid chromatography-mass spectrometric (LC-MS) method was developed, validated, and tested for the detection and quantification of seven active pharmaceutical compounds, with solid-phase extraction for analytes recovery and separation of interference from the aqueous matrix. The sensitivity achieved for the method allowed for LODs (μg/L) of 0.0439, 0.0684, 0.1219, 0.0710, 0.1129, 0.0447, 0.0837 and LOQs (μg/L) of 0.1462, 0.2281, 0.4065, 0.2367, 0.3763, 0.1492, 0.2792, for lamivudine, acetaminophen, vancomycin, ciprofloxacin, sulfamethoxazole, diclofenac, and ivermectin, respectively, within a linear range of 0.01-0.1 μg/mL. Other ICH validation parameters are also discussed. The different PCs were positive in 61 % of the tested surface waters, with diclofenac present only in two of the sampling points. The concentrations at which they occurred were variable and ranged between ND and 398.98 μg/L.

Ultrasonic Followed by Solid Phase Extraction and Liquid Chromatography-Photodiode Array for Determination of Pharmaceutical Compounds in Sediment and Soil

This work reports on the method optimization and application for quantitative analysis of non-steroidal anti-inflammatory drugs and anti-epileptic drug in soil and sediment samples. The analytes were extracted by ultrasonic extraction followed by solid phase extraction and quantified using liquid chromatographic coupled with photodiode array. The sensitivity of the method was determined based on the limit of detection and the limit of quantification which ranged between (0.010-0.027 µg/kg) and (0.025-0.049 µg/kg), respectively. The %recoveries of the method ranged between 74% and 112%. The concentrations obtained in real samples ranged from 0.055 to 0.426 µg/kg in sediment and 0.044-0.567 µg/kg in soil samples. The highest concentration was found for diclofenac in soil samples.

Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS

There is growing interest in determining the unidentified peaks within a sample spectra besides the analytes of interest. Availability of reference standards and hyphenated instruments has been a key and limiting factor in the rapid determination of emerging pollutants in the environment. In this work, polar compounds were silylated and analyzed with gas chromatography mass spectrometry (GC-MS) to determine the abundant fragments within the single ion monitoring (SIM) mode and methodology. Detection limits and recoveries of the compounds were established in river water, wastewater, biosolid and sediment matrices. Then, specific types of polar compounds that are classified as emerging contaminants, pharmaceuticals and personal care products, in the environment were targeted in the Mgeni and Msunduzi Rivers. We also performed suspect and non-target analysis screening to identify several other polar compounds in these rivers. A total of 12 compounds were quantified out of approximately 50 detected emerging contaminants in the Mgeni and Msunduzi Rivers. This study is significant for Africa, where the studies of emerging contaminants are limited and not usually prioritized.