Pharmaceuticals as emerging organic contaminants in Umgeni River water system, KwaZulu-Natal, South Africa

Transcriptomic analysis of Raphidocelis subcapitata exposed to erythromycin: The role of DNA replication in hormesis and growth inhibition

The occurrence of hormesis in the algal growth inhibition test is a major challenge in the dose-response characterization, whereas the molecular mechanism remains unraveled. The aim of this study is therefore to investigate the changes in the molecular pathways in a model green alga Raphidocelis subcapitata treated with erythromycin (ERY; 4, 80, 120 μg L^-1) by transcriptomic analysis. After 7 day exposure, ERY at 4 μg L^-1 caused hormetic effects (21.9 %) on cell density, whereas 52.0 % and 65.4 % were inhibited in two higher exposures. By using adj p < 0.05 and absolute log₂ fold change> 1 as a cutoff, we identified 218, 950, and 2896 differentially expressed genes in 4, 80, 120 μg L^-1 treatment groups, respectively. In two higher ERY treated groups, genes involved in phases I, II & III metabolism processes and porphyrin and chlorophyll metabolism pathway were consistently suppressed. Interestingly, genes (e.g., pri2, mcm2, and mcm6) enriched in DNA replication process were up-regulated in 4 μg L^-1 group, whereas these genes were all repressed in 120 μg L^-1 group. Alteration trend in gene expression was consistent with algal growth. Taken together, our results unveiled the molecular mechanism of action in ERY- stimulated/ inhibited growth in green alga.

Pharmaceuticals and personal care products in water and wastewater: a review of treatment processes and use of photocatalyst immobilized on functionalized carbon in AOP degradation

The presence of emerging contaminants such as pharmaceutical and personal care products in many aqueous matrices have been reported. One of such matrix is streams of wastewater, including wastewater treatment plants inflows and outflows and wastewater flow by-passing wastewater treatment plants. Their persistence arises from their resistant to breakdown, hence they may remain in the environment over long time, with a potential to cause adverse effects including endocrine disruption, gene toxicity, the imposition of sex organs, antibiotic resistance and many others in some aquatic organisms exposed to arrays of residues of pharmaceutical and personal care products. Among the treatment techniques, advanced oxidation processes have been reported to be a better technique through which these PPCPs can be degraded in the WWTPs. Heterogeneous photocatalysis using various photocatalyst immobilized on solid support such as activated carbon, graphene and carbon nanotubes in AOPs have been shown to be a viable and efficient method of PPCPs degradation. This is because, the performance of most WWTPs is limited since they were not designed to degrade toxic and recalcitrant PPCPs. This review highlight the occurrence, concentration of PPCPs in wastewater and the removal efficiency of heterogeneous photocatalysis of TiO2 immobilized on solid supports.

Effects of short-term exposure of paracetamol in the gonads of blue mussels Mytilus edulis

A growing body of literature suggests that pharmaceutical contamination poses an increasing risk to marine ecosystems. Paracetamol or acetaminophen is the most widely used medicine in the world and has recently been detected in seawater. Here, we present the results of 7 days' exposure of blue mussel adults to 40 ng/L, 250 ng/L and 100 μg/L of paracetamol. Histopathology shows that haemocytic infiltration is the most observed condition in the exposed mussels. The mRNA expression of VTG, V9, ER2, HSP70, CASP8, BCL2 and FAS in mussel gonads present different patterns of downregulation. VTG and CASP8 mRNA expression show downregulation in all exposed mussels, irrespective of sex. The V9, HSP70, BCL2 and FAS transcripts follow a concentration-dependent variation in gene expression and may therefore be considered good biomarker candidates. ER2 mRNA expression shows a downregulated trend, with a clearer dose-response relationship in males. In conclusion, this study suggests that paracetamol has the potential to alter the expression of several genes related to processes occurring in the reproductive system and may therefore impair reproduction in blue mussels.

Cardiovascular drugs and lipid regulating agents in surface waters at global scale: Occurrence, ecotoxicity and risk assessment

Cardiovascular drugs and lipid regulating agents have emerged as major groups of environmental contaminants over the past decades. However, knowledge about their occurrence in freshwaters and their ecotoxicity is still limited. Here, we critically summarize the presence of 82 cardiovascular drugs and lipid regulating agents at a global-scale and represent their effects on aquatic organisms. Only about 71% of these pharmaceuticals in use have been analyzed for their residues in aquatic ecosystems and only about 24% for their effects. When detected in surface waters, they occurred at concentrations of dozens to hundreds of ng/L. In wastewaters, they reached up to several μg/L. Effects of cardiovascular drugs and lipid regulating agents have been extensively studied in fish and a few in invertebrates, such as Daphnia magna and mussels. These pharmaceuticals affect cardiac physiology, lipid metabolism, growth and reproduction. Besides, effects on spermatogenesis and neurobehavior are observed. Environmental risks are associated with beta-blockers propranolol, metoprolol, and lipid lowering agents bezafibrate and atorvastatin, where adverse effects (biochemical and transcriptional) occurred partially at surface water concentrations. In some cases, reproductive effects occurred at environmentally relevant concentrations. This review summarizes the state of the art on the occurrence of cardiovascular drugs and lipid regulating agents at a global-scale and highlights their risks to fish. Further research is needed to include more subtle changes on heart function and to explore non-investigated drugs. Their occurrence in freshwaters and impact on a diverse array of aquatic organisms are particularly needed to fully assess their environmental hazards and risks.

Optimization and application of hollow fiber liquid-phase microextraction and microwave-assisted extraction for the analysis of non-steroidal anti-inflammatory drugs in aqueous and plant samples

Human consumption of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing, which poses a great risk of pollution by these pharmaceuticals on the aquatic environment. Therefore, this study reports the optimization of microwave-assisted extraction using water as a green solvent and hollow fiber liquid-phase microextraction (HF-LPME) methods followed by high-performance liquid chromatography-high resolution mass spectrometry analysis of NSAIDs in wastewater and aquatic plant, Eichhornia crassipes. The optimized MAE resulted in efficient transfer of selected NSAIDs from plant samples into the aqueous phase yielding the recoveries ranging from 91 to115%. A multivariate approach based on half fractional factorial and central composite design was used during the optimization of HF-LPME. Under the optimized conditions, the maximum enrichment factors for naproxen, fenoprofen, diclofenac, and ibuprofen were 49, 126, 93 and 156, respectively. The overall analytical method recoveries ranged from 86 to 116% while the limits of quantitation for wastewater and plant samples ranged from 0.09 to 0.59 μg L^-1 and from 0.11 to 0.59 μg kg^-1, respectively. The precision of the proposed analytical method which was measured in terms of RSD values did not exceed 5%. Naproxen was the most abundant compound in both wastewater and the Eichhornia crassipes plant samples with concentrations of up to 3.30 μg L^-1 and 10.97 μg kg^-1, respectively. The detection of NSAIDs in Eichhornia crassipes means this plant has the ability to bioaccumulate pharmaceutical load in surface water.

Poikilocytosis and tissue damage as negative impacts of tramadol on juvenile of Tilapia (Oreochromis niloticus)

Pharmaceuticals residue was detected in the water bodies as a consequence of the incomplete treatment. Recently, the side impacts of that residue on aquatic creatures have received a considerable attention. However, there is insufficient information about the effect of the most consumed narcotic drug (tramadol) on fish as an aquatic model. Thus, this study aims at investigating the poikilocytosis and tissue damage in Oreochromis niloticus after the exposure to 100 and 200 mg/L of tramadol hydrochloride. Three groups of fish were used; one as a control group, and the other two groups were exposed to 100 mg/L and 200 mg/L of tramadol hydrochloride respectively for 25 days. Exposure to tramadol caused a significant increase in the percentage of poikilocytosis compared to the control group. Poikilocytosis included tear-drop cell, spindle-shaped cell, sickle cell, schistocyte, blebbed cell, acanthocyte, eccentric nucleus, amoebocyte, dividing cell, and crenated cell. Moreover, liver tissue in fish exposed to tramadol showed degeneration and vacuolization of hepatocytes and atrophy of pancreatic acini as signs of histopathological alterations. Histopathological changes of brain showed severe gliosis, dark neurons, and vacuolization in fish exposed to tramadol compared to control fish. Gills tissue showed erosion, epithelial lifting, and secondary lamellae shrinking in fish exposed to tramadol compared to control fish. In conclusion, tramadol induced histopathological changes in liver, brain, and gills of Oreochromis niloticus as well as poikilocytosis were indicated clearly. Therefore, tramadol leakage to waters should be avoided to preserve aquatic creatures.

Accumulation characteristics and biological response of ginger to sulfamethoxazole and ofloxacin

The potential risk to human health of antibiotics that pass through the food chain has become an important global issue, but there are few reports on the response of ginger (Zingiber officinale) to antibiotic pollution. In this study, we investigated the enrichment characteristics and biological response of ginger to sulfamethoxazole (SMZ) and ofloxacin (OFL) residues, which are common in the environment. Lower levels of SMZ, OFL and their combined duplex treatment (SMZ+OFL) promoted the growth of ginger, but the critical doses necessary to stimulate growth differed among treatments: 10 mg L-1 SMZ, 1 mg L-1 OFL and 1 mg L-1 (SMZ+OFL) had the strongest stimulating effects. At higher dosages, the root growth and light energy utilization efficiency of ginger were impaired, and (SMZ+OFL) had the strongest inhibitory effect. Treatments with lower levels of antibiotics had no significant effect on reactive oxygen species and antioxidant enzyme activities. However, when SMZ, OFL and SMZ+OFL concentrations exceeded 10 mg L-1, the contents of H2O2, O2- and MDA continued to increase, while the activities of SOD, POD, CAT first increased and then decreased, especially in SMZ+OFL. Ginger accumulated more SMZ and OFL in rhizomes and less in leaves, and accumulation increased significantly as antibiotic concentration increased. When SMZ concentration was 1 mg L-1, the SMZ concentrations in rhizomes, roots, and leaves were 0.23, 0.15, and 0.05 mg kg-1, respectively, and the residual SMZ in the rhizome was 2.3 times higher than the maximum residue limit. The abundance of the resistance genes sul1, sul2, qnrS, and intI1 increased with increasing antibiotic concentrations, and intI1 abundance was the highest. OFL induced higher levels of intI1 expression than did SMZ.

Modeling electrochemical oxidation and reduction of sulfamethoxazole using electrocatalytic reactive electrochemical membranes

In this research, degradation of the antibiotic sulfamethoxazole (SMX) was studied using electrochemical reduction and oxidation in single pass, flow-through mode using porous titanium suboxide (Ti₄O₇) reactive electrochemical membranes (REMs) and Pd-Cu doped Ti₄O₇ REMs (Pd-Cu/Ti₄O₇ REMs). Electrochemical reduction of SMX increased from 3.8 ± 0.3% for the Ti₄O₇ REM to 96.1 ± 3.9% for the Pd-Cu/Ti₄O₇ REM at -1.14 V/SHE and at a permeate flux of 300 L m^-2 h^-1 (LMH) (liquid residence time: ∼1.8 s). By contrast, electrochemical oxidation using Ti₄O₇ REMs achieved 95.7 ± 1.0% removal of SMX at 2.03 V/SHE and a permeate flux of 300 LMH (liquid residence time: ∼9.0 s) without the catalyst addition. We developed a reactive transport mathematical model and calibrated it to the SMX experimental data. The calibrated model predicted SMX permeate concentrations at fixed potentials and as a function of permeate flux. Based on products from SMX reduction, we proposed that SMX was reduced by a hydrogen atom transfer reaction that was mediated by the Pd-Cu/Ti₄O₇ REM. Toxicity tests indicated that electrochemical oxidation/reduction lowered solution toxicity. The results of this work indicate that a tandem electrochemical reduction/oxidation approach using the REM-based technology is a potential treatment strategy for sulfonamide-contaminated pharmaceutical wastewater.

Characterization of the Nairobi River catchment impact zone and occurrence of pharmaceuticals: Implications for an impact zone inclusive environmental risk assessment

The largely uncontrolled release of active pharmaceuticals ingredients (APIs) within untreated wastewater discharged to waterbodies, associated with many rapidly urbanising centres is of growing concern owing to potential antimicrobial resistance, endocrine disruption and potential toxicity. A sampling campaign has been undertaken to assess the source, occurrence, magnitude and risk associated with APIs and other chemicals within the Nairobi/Athi river basin, in Kenya, East Africa. The catchment showed an extensive downstream impact zone estimated to extend 75 km, mostly, but not exclusively, derived from the direct discharge of untreated wastewater from the urban centre of Nairobi city. The exact extent of the downstream boundary of the Nairobi city impact zone was unclear owing to the inputs of untreated wastewater sources from the continuous urbanized areas along the river, which counteracted the natural attenuation caused by dilution and degradation. The most frequently detected APIs and chemicals were caffeine, carbamazepine, trimethoprim, nicotine, and sulfamethoxazole. Paracetamol, caffeine, sulfamethoxazole, and trimethoprim alone contributed 86% of the total amount of APIs determined along the Nairobi/Athi catchment. In addition to direct discharge of untreated domestic wastewater attributed to the informal settlements within the conurbation, other sources were linked to the industrial area in Nairobi City where drug formulation is known to occur, the Dandora landfill and veterinary medicines from upstream agriculture. It was shown that there was a possible environmental risk of API ecotoxicological effects beyond the end of the traditional impact zone defined by elevated biochemical oxygen demand concentrations; with metronidazole and sulfamethoxazole exhibiting the highest risk.

Using a high-throughput zebrafish embryo screening approach to support environmental hazard ranking for cardiovascular agents

Cardiovascular agents are among the most frequently prescribed pharmaceuticals worldwide. They are widely detected in aquatic ecosystems, while their ecotoxicological implications are rarely explored. Here, by the use of a new developed high-throughput zebrafish embryo screening approach, we systematically assessed the cardiovascular disruptive effects of 32 commonly used cardiovascular agents at environmental relevant concentrations and above (0.04, 0.2 and 1 µM). Multiple endpoints, including cardiac output, heart rate and blood flow, were quantified via customized video analysis approaches. Among the 32 agents, simvastatin and lovastatin exhibited the strongest toxicities to fish embryos, and the lethal doses were observed at 0.2 µM and 1 µM. Beta-blockers such as atenolol and metoprolol significantly decreased heart rates by up to 15% and 12% and increased blood flows by up to 14% and 14%, respectively, at concentrations as low as 0.04 µM. Several hypertension/hyperlipidemia medications such as pravastatin and enalapril led to significant inhibition of heart rates (up to 14% and 16% decreases, respectively) as well as slightly decreases of the cardiac outputs and blood flows. In addition, a tentative risk assessment clearly demonstrated that some compounds such as atenolol, metoprolol and bezafibrate pose considerable risks to aquatic organisms at environmental or slightly higher than surface water concentrations. Our results provided novel insights into understanding of the potential risks of cardiovascular agents and contributed to their environmental hazard ranking.

Biological removal of pharmaceuticals by Navicula sp. and biotransformation of bezafibrate

Pharmaceutically active compounds are of great concern due to their detection frequency in the environment and the unexpected risks. In this study, the simultaneous removal of mixed pharmaceuticals by microalgae was explored using a typical freshwater diatom Navicula sp. Results showed that Navicula sp. could efficiently remove atenolol, carbamazepine, ibuprofen and naproxen with the efficiencies of >90% after 21 d of exposure. As compared to the removal efficiencies of each pharmaceutical in the individual pharmaceutical treatments, the degradation of sulfamethoxazole, bezafibrate, and naproxen was improved in the mixed treatment, whereas the removal efficiencies of carbamazepine and atenolol decreased. Additionally, the presence of hydrophobic pharmaceuticals (i.e., ibuprofen and naproxen) accelerated the degradation of carbamazepine and sulfamethoxazole and inhibited the removal of atenolol in the mixture with the combination of six pharmaceuticals, while the addition of other pharmaceuticals show no significant effect on the removal of ibuprofen and naproxen. The bioaccumulation of pharmaceuticals in Navicula sp. increased as their log K_OW values decreased. Four bezafibrate metabolites were identified and the degradation pathways of bezafibrate in diatom were proposed. It is the first report on the metabolism of BEZ in diatom, and further studies on the environmental risk of the metabolites should be investigated.

Surface Water and Groundwater Quality in South Africa and Mozambique—Analysis of the Most Critical Pollutants for Drinking Purposes and Challenges in Water Treatment Selection

According to a recent report by the World Health Organization (WHO), the countries which still have limited access to water for drinking purposes are mainly those in the Sub-Saharan region. In this context, the current study provides an overview of the quality of surface water and groundwater in rural and peri-urban areas of the Republic of South Africa (RSA) and Mozambique (MZ) in terms of concentrations of conventional pollutants, inorganic chemicals, microorganisms, and micropollutants. Their values were compared with the drinking water standards available for the two countries. Regarding surface water, it was found that microorganisms occur at high concentrations; nickel (RSA) and boron (MZ) are other critical parameters. Regarding groundwater, arsenic and lead (RSA) and boron, sodium, and chloride (MZ) are the main critical substances. With regard to micropollutants, their surface water concentrations are much higher than those in European rivers. The highest values were for ibuprofen, acetylsalicylic acid, clozapine, and estriol. Suitable treatment is necessary to produce safe water depending on the main critical pollutants but, at the same time, action should be taken to improve wastewater treatment in rural areas to improve and safeguard surface water bodies and groundwater which are sources for drinking needs.

Fate, occurrence and potential adverse effects of antimicrobials used for treatment of tuberculosis in the aquatic environment in South Africa

The consumption of tonnes of anti-tubercular and other anti-microbial compounds for the control of the tuberculosis epidemic and other opportunistic diseases associated with human immunodeficiency virus presents tuberculosis-endemic countries such as South Africa, with a problem regarding the occurrence and fate of these compounds in the aquatic environment. The majority of these compounds are not readily degradable and could persist in the aquatic environment with potential detrimental effect on the aquatic microbiota ecosystem, development and dissemination of anti-microbial resistance as well as chronic toxicity in humans due to long-term exposure. This review summarises and discusses the occurrence, fate and potential adverse effects of the commonly administered anti-tubercular compounds in the aquatic environment in tuberculosis-endemic countries and South Africa in particular. It further attempts to identify information gaps in the literature regarding anti-tubercular compounds in the environment that needs further investigation so that their risk can be comprehensively assessed and impact mitigated.

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.

Pharmaceutically active compounds in aqueous environment: A status, toxicity and insights of remediation

Pharmaceutically active compounds (PhACs) have pernicious effects on all kinds of life forms because of their toxicological effects and are found profoundly in various wastewater treatment plant influents, hospital effluents, and surface waters. The concentrations of different pharmaceuticals were found in alarmingly high concentrations in various parts of the globe, and it was also observed that the concentration of PhACs present in the water could be eventually related to the socio-economic conditions and climate of the region. Drinking water equivalent limit for each PhAC has been calculated and compared with the occurrence data from various continents. Since these compounds are recalcitrant towards conventional treatment methods, while advanced oxidation processes (AOPs) have shown better efficiency in degrading these PhACs. The performance of the AOPs have been evaluated based on percentage removal, time, and electrical energy consumed to degrade different classes of PhACs. Ozone based AOPs were found to be favorable because of their low treatment time, low cost, and high efficiency. However, complete degradation cannot be achieved by these processes, and various transformation products are formed, which may be more toxic than the parent compounds. The various transformation products formed from various PhACs during treatment have been highlighted. Significant stress has been given on the role of various process parameters, water matrix, oxidizing radicals, and the mechanism of degradation. Presence of organic compounds, nitrate, and phosphate usually hinders the degradation process, while chlorine and sulfate showed a positive effect. The role of individual oxidizing radicals, interfering ions, and pH demonstrated dissimilar effects on different groups of PhACs.

Concentration and reduction of antibiotic residues in selected wastewater treatment plants and receiving waterbodies in Durban, South Africa

In the province of KwaZulu-Natal, South Africa the incidence of resistant tuberculosis, upper respiratory tract diseases as well as diarrhoeal and parasitic infections is high. Treatment of these diseases with antibiotics is partly reflected by the excretion of the respective antibiotics and their subsequent occurrence in wastewater. Their quantitative reduction in wastewater treatment reflects their potential environmental as well as human impact, the latter due to the use of the recipient water for domestic purposes and for irrigation. Information of the occurrence and reduction of different classes of antibiotics in wastewater treatment is sparse, especially the particle bound fraction of these. Due to this, analyses of aqueous and particle bound antibiotics in untreated wastewater of four selected wastewater treatment plants (WWTPs) and their receiving water bodies was carried out in Durban, South Africa. The treatment step especially considered was the biological one, represented by activated sludge and trickling filters. The treatment further included secondary clarifiers and final chlorine disinfection. Composite samples were collected during the period February 2017 to May 2017 and analysed with online solid phase extraction - high performance liquid chromatography mass spectrometry (SPE-HPLC-MS). For the 13 assessed antibiotics, the limit of detection (LOD) and the limit of quantification (LOQ) ranged from 0.07 to 0.33 ng L^-1 and 0.23 to 1.09 ng L^-1 respectively, while the total percentage recovery was in the range of 51 to 111%. The percentage of individual antibiotics bound to the particulate fraction normally lost by sample (influent) filtration, if not analysed in parallel, was in the range of 2.6%-97.3% (n = 32). In this fraction (sludge from centrifuge sample), the concentration of bound antibiotics of all the target antibiotics were detected in the influent of all WWTP in concentration ranges between 1.3 ng L^-1 (Azithromycin; AZI) to 81,748 ng L^-1 (Ciprofloxacin; CIP). The antibiotics with the highest median concentrations in receiving water bodies of the respective WWTP were; Sulfamethoxazole; SUL (239 ng L^-1) WWTP "K", Ciprofloxacin; CIP (708 ng L^-1) WWTP "S" and Albendazole; ALB (325 ng L^-1 and 683 ng L^-1) WWTP "P" and "I" respectively. The overall percentage removal efficiency for the four WWTPs ranged from 21% to 100%. The biological treatment steps, activated sludge and trickling filters, were effective in removing antibiotics especially with the trickling filter and the impact of the sedimentation stage after activated sludge treatment.

Hatching success and survival of fish early life stages in a chronic exposure to nevirapine: a case study of the Mozambique tilapia

The anti-retroviral nevirapine has been detected in surface waters throughout South Africa and its effects on non-target aquatic animals are still unknown. The aim was to investigate the potential effects of nevirapine on the hatching success and survival of Oreochromis mossambicus early life stages through a chronic exposure. The exposer started with newly fertilized O. mossambicus eggs and concluded 30 days after hatching. Environmental relevant concentration of nevirapine (1.48 µg/l) was used in a static renewal system and a controlled environment (27 ± 1°C; 14:10 day/night cycle). The main endpoints assessed included hatching success and survival; a morphological assessment was also done on whole individual on day 1 and 30 post-hatching to identify any physical abnormality. Nevirapine had no noticeable effects on the hatching success and survival of O. mossambicus larvae; no statistically significant differences were observed between the control and the nevirapine exposed fish (p > 0.05).

Pharmaceuticals, herbicides, and disinfectants in agricultural water sources

Agricultural water withdrawals account for the largest proportion of global freshwater use. Increasing municipal water demands and droughts are straining agricultural water supplies. Therefore, alternative solutions to agricultural water crises are urgently needed, including the use of nontraditional water sources such as advanced treated wastewater or reclaimed water, brackish water, return flows, and effluent from produce processing facilities. However, it is critical to ensure that such usage does not compromise soil, crop, and public health. Here, we characterized five different nontraditional water types (n = 357 samples) for the presence of pharmaceuticals, herbicides, and disinfectants using ultra-high-pressure liquid chromatography tandem mass spectrometry based method (UPLC-MS/MS). We then evaluated whether the levels of these contaminants were influenced by season. The highest level of herbicides (atrazine) was detected in untreated pond water (median concentration 135.9 ng/L). Reclaimed water had the highest levels of antibiotics and stimulants including azithromycin (215 ng/L), sulfamethoxazole (232.1 ng/L), and caffeine (89.4 ng/L). Produce processing plant water also tended to have high levels of atrazine (102.7 ng/L) and ciprofloxacin (80.1 ng/L). In addition, we observed seasonal variability across water types, with the highest atrazine concentrations observed during summer months, while the highest median azithromycin concentrations were observed in reclaimed water during the winter season. Further studies are needed to evaluate if economically feasible on-farm water treatment technologies can effectively remove such contaminants from nontraditional irrigation water sources.

Use of the Chemcatcher® passive sampler and time-of-flight mass spectrometry to screen for emerging pollutants in rivers in Gauteng Province of South Africa

Many rivers in urbanised catchments in South Africa are polluted by raw sewage and effluent to an extent that their ecological function has been severely impaired. The Hennops and Jukskei Rivers lying in the Hartbeespoort Dam catchment are two of the worst impacted rivers in South Africa and are in need of rehabilitation. Passive sampling (Chemcatcher® with a HLB receiving phase) together with high-resolution tandem mass spectrometry-targeted screening was used to provide high sensitivity and selectivity for the identification of a wide range of emerging pollutants in these urban waters. Over 200 compounds, including pesticides, pharmaceuticals and personal care products, drugs of abuse and their metabolites were identified. Many substances (~ 180) being detected for the first time in surface water in South Africa. General medicines and psychotropic drugs were the two most frequently detected groups in the catchment. These accounted for 49% of the emerging pollutants found. Of the general medicines, antihypertensive agents, beta-blocking and cardiac drugs were the most abundant (28%) classes detected. The Hennops site, downstream of a dysfunctional wastewater treatment plant, was the most polluted with 123 substances detected. From the compounds detected, peak intensity-based prioritisation was used to identify the five most abundant pollutants, being in the order caffeine > lopinavir > sulfamethoxazole > cotinine > trimethoprim. This work provides the largest available high-quality dataset of emerging pollutants detected in South African urban waters. The data generated in this study provides a solid foundation for subsequent work to further characterise (suspect screening) and quantify (target analysis) these substances.

Pharmaceuticals in freshwater aquatic environments: A comparison of the African and European challenge

Hundreds of tons of pharmaceutical compounds are annually dispensed and consumed worldwide. Pharmaceuticals are an important class of emerging environmental micropollutants: their presence in water bodies is an increasing environmental concern. The aim of this review paper is to provide a comprehensive review of the occurrence of pharmaceuticals in freshwater aquatic environments in the African and European context. A literature survey has been performed, resulting in 3024 data points related to environmental occurrence. The concentration levels of 71 pharmaceuticals were assessed. The top ten most frequently detected and quantified compounds in both continents were sulfamethoxazole, carbamazepine, diclofenac, trimethoprim, ibuprofen, naproxen, paracetamol (acetaminophen), ketoprofen, venlafaxine and clarithromycin. The maximum concentrations of 17β-estradiol, estriol, ciprofloxacin, sulfamethoxazole, paracetamol, naproxen reported in African aquatic environments were ~3140, ~20,000, ~125, ~100, ~215 and ~171 times higher, respectively, than the concentrations reported in European based studies. The variation in pharmaceutical consumption, partial removal of pharmaceuticals in wastewater treatment processes, and the direct discharge of livestock animal farm wastewater were identified among the major reasons for the observed differences. Several pharmaceuticals were found in aquatic environments of both continents in concentration levels higher than their ecotoxicity endpoints. In Europe, compounds such as diclofenac, ibuprofen, triclosan, sulfadimidine, carbamazepine and fluoxetine were reported in a concentration higher than the available ecotoxicity endpoints. In Africa, much more compounds reached concentrations more than the ecotoxicity endpoints, including diclofenac, ibuprofen, paracetamol, naproxen, ciprofloxacin, triclosan, trimethoprim, sulfamethoxazole, carbamazepine and fluoxetine, estriol and 17β-estradiol. Details for each therapeutic group are presented in this review.

Synthesis and application of a molecularly imprinted polymer in selective solid-phase extraction of efavirenz from water

Efavirenz is one of the antiretroviral drugs widely used to treat the human immunodeficiency virus. Antiretroviral drugs have been found to be present in surface water and wastewater. Due to complexity of environmental samples, solid-phase extraction (SPE) is used for isolation and pre-concentration of antiretroviral drugs prior to their chromatographic analysis. However, the commercially available SPE sorbents lack selectivity, which tends to prolong the analysis time. Therefore, in this study a molecularly imprinted polymer was synthesized for the specific recognition of efavirenz and then applied as the SPE sorbent for its extraction from wastewater and surface water samples. The imprinted and non-imprinted polymers were synthesized using a bulk polymerization technique where efavirenz was used as the template, 2-vinylpyridine as functional monomer, 1,1'-azobis-(cyclohexanecarbonitrile) as initiator, ethylene glycol dimethacrylate as cross-linker and toluene:acetonitrile (9:1, v/v) as the porogenic solvent mixture. The characterization was performed using Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, elemental analysis, and thermogravimetric analysis techniques. Results showed better selectivity of molecularly imprinted polymer to efavirenz than did non-imprinted polymer. The analysis was performed using high performance liquid chromatography equipped with a photo-diode array detector. The analytical method gave a detection limit of 0.41 μg/L and the analyte recovery of 81% in wastewater. The concentrations found in wastewater ranged from 2.79 to 120.7 μg/L, while in surface water they were between 0.975 and 2.88 μg/L. Therefore, the results of this study show a strong need for a detailed screening of efavirenz in major water utilities in the country.

Synthesis of a molecularly imprinted polymer and its application in selective extraction of fenoprofen from wastewater

The presence of various classes of pharmaceutical drugs in different environmental compartments has been reported worldwide. In South Africa, the detection of pharmaceuticals especially the non-steroidal anti-inflammatory drugs is recent, and more studies are being done in order to fully understand their fate in the aquatic environment. With considerations for the need of better sample preparation techniques, this study synthesized a molecularly imprinted polymer for the selective extraction of a non-steroidal anti-inflammatory drug, fenoprofen in aqueous environmental samples. Batch adsorption studies showed that adsorption of fenoprofen onto the cavities of the polymer followed a Langmuir isotherm as well as a pseudo second order model implying formation of a monolayer on the surface through chemisorption. The polymer had a maximum adsorption capacity of 38.8 mg g^-1 and a Langmuir surface area of 1607 m² g^-1. The imprinted polymer was then used as the selective sorbent for solid phase extraction in the analysis of fenoprofen from wastewater followed by chromatographic determination. The analytical method gave a detection limit of 0.64 ng mL^-1 and recovery of 99.6%. The concentration of fenoprofen detected in influent and effluent samples from two wastewater treatment plants ranged from 24 to 58 ng mL^-1. The ability of the treatment plants to remove fenoprofen during wastewater processing based on the difference in concentrations in influent and effluent samples was found to be 41%. This work has shown that there is a possibility of release of fenoprofen from wastewater treatment plants into surface water sources.

Assessment of Pharmaceuticals, Personal Care Products, and Hormones in Wastewater Treatment Plants Receiving Inflows from Health Facilities in North West Province, South Africa

The presence of 17 pharmaceutical and personal care products (PPCPs) belonging to various therapeutic categories was investigated in two hospital wastewater treatment plants (WWTPs) in North West Province, South Africa. The compounds were extracted from wastewater samples by solid-phase extraction and analysed by liquid chromatography-tandem mass spectrometry. The results showed that ofloxacin, chloramphenicol, and bezafibrate were generally below the limit of quantification (LOQ) in the analysed samples. Acetaminophen and ibuprofen were the dominant pharmaceuticals in the influent streams with corresponding concentrations ranging from 21 to 119 μg/L and 0.3 to 63 μg/L, respectively. Both WWTPs were shown to have the capability to remove some of the target PPCPs, including acetaminophen (76-98%), tetracycline (15-93%), ibuprofen (44-99%), and triclocarban (13-98%). The monitoring of the target PPCPs in both influent and effluent samples of the investigated WWTPs revealed that the discharge of inadequately treated effluents could be contributing to the possible increase in the concentrations of these contaminants in the receiving environmental compartments. Further studies must be focused on the broader characterisation of these matrices in order to assess the potential ecological impacts of this waste disposal practice.

Antibiotic Residue in the Aquatic Environment: Status in Africa

Information on the presence of antibiotics is sparse for all types of water in Africa, including groundwater, surface water, effluent of wastewater treatment plants (WWTPs) and municipal potable water. With the relatively high sales of different antibiotics to treat infectious diseases in the human population of Africa, the residual of the antibiotics is bound to be released through excretion via urine or fecal matter in parallel to the high sales. This article reviews the published analysis on the occurrence of antibiotics in the environment particularly in the aquatic environment in some countries in Africa. In general, sulfamethoxazole was the most commonly detected in Africa surface water (with eight reports from four countries) at a concentration range of 0.00027 – 39 μgL-1. Wastewater analysis is believed to give an early warning for preventing epidemics. Thus, we discuss the associated level of antibiotic resistance to some prevalent diseases in Africa whose aetiological agents can develop antibiotic resistance due to exposure to antibiotic residue in water. This is important because of rising population of immuno-deficient African residents ravaged by HIV/AIDS, poor nutrition and less efficient sanitation systems.

Electrochemical remediation of amoxicillin: detoxification and reduction of antimicrobial activity

Amoxicillin (AMX) is one of the most commonly prescribed antibiotics around the world to treat and prevent several diseases in both human and veterinary medicine. Incomplete removal of AMX during wastewater treatment contributes to its presence in water bodies and drinking water. AMX is an emerging contaminant since its impact on the environment and human health remains uncertain. This contribution was aimed to evaluate the electrochemical oxidation (EO) of AMX using different anodes in tap water, NaCl or Na₂SO₄ solutions and to evaluate the potential toxicity of remaining AMX and its by-products on zebrafish early-life stages. Chemical intermediates generated after EO were determined by mass spectrometry and their resulting antimicrobial activity was evaluated. AMX did not induce significant mortality in zebrafish during extended exposure but affected zebrafish development (increased body length) from 6.25 mg/L to 25 mg/L and inhibited enzymatic biomarkers. Carbon modified with titanium oxide (TiO₂@C) anode achieved complete AMX removal in just a few minutes and efficiency of the supported electrolytes occurred in the following order: 0.1 M NaCl > 0.1 M Na₂SO₄ > 0.01 M NaCl > tap water. The order of potential toxicity to zebrafish early life-stages related to lethal and sublethal effects was as follows: 0.1 M Na₂SO₄ > 0.1 M NaCl >0.01 M NaCl = tap water. Additionally, the EO of AMX using TiO₂@C electrode with 0.01 M NaCl was able to inhibit the antimicrobial activity of AMX, reducing the possibility of developing bacterial resistance.

Contaminants of emerging concern in the Hartbeespoort Dam catchment and the uMngeni River estuary 2016 pollution incident, South Africa

A quantitative assessment of pollutants of emerging concern in the Hartbeespoort Dam catchment area was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to establish the occurrence, source and distribution of 15 environmental pollutants, including 10 pharmaceuticals, 1 pesticide and 4 steroid hormones. Seasonal sampling was conducted in the Hartbeespoort Lake using sub-surface grab sampling to determine the lake's ecological status and obtain data for establishment of progressive operational monitoring. The Jukskei River, which lies upstream of the Hartbeespoort Dam, was sampled in the winter season. Five year old carp (Cyprinus carpio) and catfish (Clarias gariepinus) were also sampled from the Hartbeespoort Dam to study bioaccumulation in biota as well as to estimate risk associated with fish consumption. In the Jukskei River, the main source of 11 emerging pollutants (EPs) was identified as raw sewage overflow, with the highest ∑11 EP concentration of 593ngL^-1 being recorded at the Midrand point and the lowest ∑11 EP concentration of 164ngL^-1 at the N14 site located 1km downstream of a large wastewater treatment plant. The Jukskei River was found to be the largest contributor of the emerging contaminants detected in the Hartbeespoort Dam. In the Hartbeespoort Dam EP concentrations were generally in the order efavirenz>nevirapine>carbamazepine>methocarbamol>bromacil>venlafaxine. Water and sediment were sampled from the uMngeni River estuary within 24h after large volumes of an assortment of pharmaceutical waste had been discovered to be washed into the river estuary after flash rainfall on 18 May 2016. Analytical results revealed high levels of some emerging pollutants in sediment samples, up to 81ngg^-1 for nevirapine and 4ngg^-1 for etilefrine HCL. This study shows that efavirenz, nevirapine, carbamazepine, methocarbamol, bromacil and venlafaxine are contaminants that require operational monitoring in South African urban waters.

Sorption of active pharmaceutical ingredients in untreated wastewater effluent and effect of dilution in freshwater: Implications for an "impact zone" environmental risk assessment approach

Evidence of ecotoxicological effects of active pharmaceuticals ingredients (APIs) has increased research into their environmental fate. In low and low-middle income countries (LLMICs) the main source of APIs to surface waters is from discharge of untreated wastewater. Consequently, concentrations of APIs can be relatively high in the "impact zone" downstream of a discharge point. Little is known about the fate of APIs in these impact zones. In this laboratory scale investigation, the effect of successive dilution of synthetic untreated wastewater (dilution factor 1 to 10) on the distribution of APIs was studied. The sorption was consistent with the chemical properties of each compound: charge, lipophilicity, and structure. Dilution increased desorption of the basic and neutral APIs (up to 27.7%) and correlated with their lipophilicity (R²>0.980); the positive charge was of secondary importance. Anions did not significantly desorb (<10% loss). Increased concentrations of dissolved organic matter at dilutions of 8 and 10 times that of untreated wastewater coincided with lower dissolved API concentrations. The data showed a clear trend in the desorption process of APIs that may lead to higher exposure risk than anticipated. Therefore, it is suggested that these aspects should be accounted for in the development of dedicated environmental risk assessment approach for APIs in riverine impact zones of LLMICs countries.

Organic contaminants in African aquatic systems: Current knowledge, health risks, and future research directions

Organic contaminants (OCs) are increasingly being reported in African aquatic systems, yet a critical evaluation of the literature is still lacking. The objectives of this review were to: (1) identify hotspot reservoirs, transfer pathways and ecological and human risks of OCs, (2) identify potential interventions to minimize the health risks, and (3) highlight knowledge gaps and research constraints. OCs widely reported in aquatic systems include pesticides, pharmaceuticals, plasticizers, solvents, endocrine disrupting compounds, and antimicrobial resistance genes, originating from applications in crop protection, veterinary and animal husbandry, human sanitation and hygiene, human vector and disease control. Potential hotspot reservoirs of OCs include wastewaters, on-site sanitation systems, leachates from non-engineered landfills and contaminated recharge of shallow groundwater systems. OCs could be transferred into humans via drinking of contaminated water, consumption of contaminated crops and aquatic foods, and to a lesser extent, inhalation and dermal contact. Ecological effects including intersex, estrogenicity, and acute and chronic toxicity occur in avian and aquatic species. Although the evidence base of human ecotoxicological effects of OC remains weak, pesticides have been reported in human milk, serum and sperms, pointing to potential chronic and acute toxicity and endocrine disruption. The prevalence of antimicrobials and their resistance genes could in turn lead to antimicrobial resistance in humans. The lack of OC monitoring in drinking water, coupled with over-reliance on untreated drinking water vulnerable to OC contamination predisposes humans to OC health risks. Appropriate water treatment methods, were identified, and a conceptual framework developed to minimize the ecological and human health risks. Future research directions on OC hotspot reservoirs, environmental behaviour and fate, ecotoxicology, epidemiology and interventions to minimize health risks are highlighted. However, lack of advanced analytical facilities in most African countries and other developing regions will continue to constrain OC research for now and in the foreseeable future.

Application of as-synthesised MCM-41 and MCM-41 wrapped with reduced graphene oxide/graphene oxide in the remediation of acetaminophen and aspirin from aqueous system

In this study, ASM41 (as-synthesised MCM-41), MCM-41, MCM-41 encapsulated with graphene oxide (MCM-41-GO) and reduced graphene oxide (MCM-41-G) were fabricated and utilized in the remediation of acetaminophen and aspirin from water. A surfactant template (cetyltrimethylammonium bromide) was added to ASM41 to make it more hydrophobic and its effects on the remediation of acetaminophen and aspirin from wastewater was studied. To further improve the adsorption capacity of the adsorbent, MCM-41 was encapsulated with GO and G which also aided in easy separation of the adsorbent from the aqueous solution. Comparative studies of the adsorption of acetaminophen and aspirin on all four adsorbents were investigated. Batch adsorption studies of acetaminophen and aspirin were carried out to determine the effects of pH, initial concentration, time and adsorbent dose. Adsorption mechanism was through EDA, π-π interactions, and hydrophobic effects. Data from sorption kinetics showed ASM41 had the highest q_m value for aspirin (909.1 mg/g) and MCM-41-G had the highest q_m value for acetaminophen (555.6 mg/g). The significant adsorption by ASM41 can be attributed to increased hydrophobicity due to the retention of the surfactant template. Thermodynamic studies revealed the adsorption process as spontaneous and exothermic. Desorption studies revealed that adsorbents could be regenerated and reused for adsorption.

Combined effects of binary antibiotic mixture on growth, microcystin production, and extracellular release of Microcystis aeruginosa: application of response surface methodology

The interactive effects of binary antibiotic mixtures of spiramycin (SP) and ampicillin (AMP) on Microcystis aeruginosa (MA) in terms of growth as well as microcystin production and extracellular release were investigated through the response surface methodology (RSM). SP with higher 50 and 5% effective concentrations in MA growth was more toxic to MA than AMP. RSM model for toxic unit approach suggested that the combined toxicity of SP and AMP varied from synergism to antagonism with SP/AMP mixture ratio decreasing from reversed equitoxic ratio (5:1) to equitoxic ratio (1:5). Deviations from the prediction of concentration addition (CA) and independent action (IA) model further indicated that combined toxicity of target antibiotics mixed in equivalent ratio (1:1) varied from synergism to antagonism with increasing total dose of SP and AMP. With the increase of SP/AMP mixture ratio, combined effect of mixed antibiotics on MA growth changed from stimulation to inhibition due to the variation of the combined toxicity and the increasing proportion of higher toxic component (SP) in the mixture. The mixture of target antibiotics at their environmentally relevant concentrations with increased total dose and SP/AMP mixture ratio stimulated intracellular microcystin synthesis and facilitated MA cell lysis, thus leading to the increase of microcystin productivity and extracellular release.

Database-driven screening of South African surface water and the targeted detection of pharmaceuticals using liquid chromatography - High resolution mass spectrometry

Pharmaceuticals and personal care products are released into aquatic environments, largely as a result of ineffectual removal during wastewater treatment. Here we present a screening strategy based on the use of three commercially available mass spectral databases, combined into a single searchable entity and parallelized by cluster computing. In addition to this, a targeted solid phase extraction method with Ultra High Pressure Liquid Chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF) was used to quantify 99 pharmaceuticals in South African surface water on a national level. Limits of quantification were in the low ng/L range for the majority of the compounds and it was found that nationally both Lamotrigine and Nevirapine occurred most often. Prednisolone and Ritonavir were present at the highest average concentration; 623 and 489 ng/L respectively. It is however shown that more than 50% of the targets chosen for analysis are not detectable in any of the samples, which highlights the utility of untargeted, database driven screening; prior to the use of costly analytical standards. Untargeted screening detected 45% of the compounds detected in targeted mode, and furthermore tentatively identified a total of 4273 unique compounds across the samples. Automatically triggered MS/MS analyses yielded 92 unique hits with greater than 95% confidence. It is therefore suggested that untargeted screening should precede the targeted approach as a matter of economy and to guide the selection of targets for quantification. There is however great room for improvement in current commercial database search methodologies as a large bottleneck exists due to processing time.

Development of the hybrid cells in series model to simulate ammonia nutrient pollutant transport along the Umgeni River

Discharge of organic waste results in high nutrient pollution of the water bodies which is a major menace to the environment. A high quantity of nutrients such as ammonia causes a reduction in the dissolved oxygen level and induces algal growth in the water bodies. Water quality models have been the tools to evaluate the rate at which streams can disperse the pollutants they receive. Many water quality models are flawed either because of their inadequacy to completely simulate the advection component of the pollutant transport, or because of the limited application of the models, due to inaccurate estimation of model parameters. The hybrid cell in series (HCIS) developed by Ghosh et al. (2004) has been able to overcome such difficulties associated with the mixing cell-based models. Thus, the current study focuses on developing an analytical solution for the pollutant transport of the ammonia concentration through the plug flow, the first and second well-mixed cells of the HCIS model. The HCIS model coupled with the first order kinetic equation for ammonia nutrient was developed to simulate the ammonia pollutant concentration in the water column. The ammonia concentration at various points along the river system was assessed by considering the effects of the transformation of ammonia to nitrite, the uptake of ammonia by the algae, the respiration rate of the algae and the input of benthic source to the ammonia concentration in the water column. The proposed model was tested using synthetic data, and the HCIS-NH₃ model simulations for spatial and temporal variation of ammonia pollutant transport were analysed. The simulated results of the HCIS-NH₃ model agreed with the Fickian-based advection-dispersion equation (ADE) for simulating ammonia concentration solved using an explicit finite difference scheme. The HCIS-NH₃ model also showed a good agreement with the observed data from the Umgeni River, except during rainy periods.

Identification of antibiotics in wastewater: current state of extraction protocol and future perspectives

The release and occurrence of antibiotics in the aquatic environment has generated increased attention in the past few decades. The residual antibiotic in wastewater is important in the selection for antimicrobial resistance among microorganisms and the possibility of forming toxic derivatives. This review presents an assessment of the advancement in methods for extraction of antibiotics with solid phase extraction and liquid-liquid extraction methods applied in different aquatic environmental media. These advanced methods do enhance specificity, and also exhibit high accuracy and recovery. The aim of this review is to assess the pros and cons of the methods of extraction towards identification of quinolones and sulphonamides as examples of relevant antibiotics in wastewater. The challenges associated with the improvements are also examined with a view of providing potential perspectives for better extraction and identification protocols in the near future. From the context of this review, magnetic molecular imprinted polymer is superior over the remaining extraction methods (with the availability of commercial templates and monomers), is based on less cumbersome extraction procedures, uses less solvent and has the advantage of its reusable magnetic phase.

Occurrence of naproxen, ibuprofen, and diclofenac residues in wastewater and river water of KwaZulu-Natal Province in South Africa

The present paper reports a detailed study that is based on the monitoring of naproxen, ibuprofen, and diclofenac in Mbokodweni River and wastewater treatment plants (WWTPs) located around the city of Durban in KwaZulu-Natal Province of South Africa. Target compounds were extracted from water samples using a multi-template molecularly imprinted solid-phase extraction prior to separation and quantification on a high-performance liquid chromatography equipped with photo diode array detector. The analytical method yielded the detection limits of 0.15, 1.00, and 0.63 μg/L for naproxen, ibuprofen, and diclofenac, respectively. Solid-phase extraction method was evaluated for its performance using deionized water samples that were spiked with 5 and 50 μg/L of target compounds. Recoveries were greater than 80% for all target compounds with RSD values in the range of 4.1 to 10%. Target compounds were detected in most wastewater and river water samples with ibuprofen being the most frequently detected pharmaceutical. Maximum concentrations detected in river water for naproxen, ibuprofen, and diclofenac were 6.84, 19.2, and 9.69 μg/L, respectively. The concentrations of target compounds found in effluent and river water samples compared well with some studies. The analytical method employed in this work is fast, selective, sensitive, and affordable; therefore, it can be used routinely to evaluate the occurrence of acidic pharmaceuticals in South African water resources.

Status of pharmaceuticals in African water bodies: Occurrence, removal and analytical methods

In this review paper, the milestones and challenges that have been achieved and experienced by African Environmental Scientists regarding the assessment of water pollution caused by the presence of pharmaceutical compounds in water bodies are highlighted. The identification and quantification of pharmaceuticals in the African water bodies is important to the general public at large due to the lack of information. The consumption of pharmaceuticals to promote human health is usually followed by excretion of these drugs via urine or fecal matter due to their slight transformation in the human metabolism. Therefore, large amounts of pharmaceuticals are being discharged continuously from wastewater treatment plants into African rivers due to inefficiency of employed sewage treatment processes. Large portions of African communities do not even have proper sanitation systems which results in direct contamination of water resources with human waste that contains pharmaceutical constituents among other pollutants. Therefore, this article provides the overview of the recent studies published, mostly from 2012 to 2016, that have focused on the occurrence of different classes of pharmaceuticals in African aqueous systems. Also, the current analytical methods that are being used in Africa for pharmaceutical quantification in environmental waters are highlighted. African Scientists have started to investigate the materials and remediation processes for the elimination of pharmaceuticals from water.

The fate of pharmaceuticals and personal care products (PPCPs), endocrine disrupting contaminants (EDCs), metabolites and illicit drugs in a WWTW and environmental waters

A large number of emerging contaminants (ECs) are known to persist in surface waters, and create pressure on wastewater treatment works (WWTW) for their effective removal. Although a large database for the levels of these pollutants in water systems exist globally, there is still a lack in the correlation of the levels of these pollutants with possible long-term adverse health effects in wildlife and humans, such as endocrine disruption. The current study detected a total of 55 ECs in WWTW influent surface water, 41 ECs in effluent, and 40 ECs in environmental waters located upstream and downstream of the plant. A list of ECs persisted through the WWTW process, with 28% of all detected ECs removed by less than 50%, and 18% of all ECs were removed by less than 25%. Negative mass balances of some pharmaceuticals and metabolites were observed within the WWTW, suggesting possible back-transformation of ECs during wastewater treatment. Three parental illicit drug compounds were detected within the influent of the WWTW, with concentrations ranging between 27.6 and 147.0 ng L^-1 for cocaine, 35.6-120.6 ng L^-1 for mephedrone, and 270.9-450.2 ng L^-1 for methamphetamine. The related environmental risks are also discussed for some ECs, with particular reference to their ability to disrupt endocrine systems. The current study propose the potential of the pharmaceuticals carbamazepine, naproxen, diclofenac and ibuprofen to be regarded as priority ECs for environmental monitoring due to their regular detection and persistence in environmental waters and their possible contribution towards adverse health effects in humans and wildlife.

Ionic liquids for the passive sampling of sulfonamides from water-applicability and selectivity study

Ionic liquids (ILs) are new-generation, non-volatile solvents which are designable, and their structure may be specifically adjusted to the current application needs. Therefore, it is possible to create and apply ILs which efficiently and selectively extract various analytes from different matrices. It has already been examined that ILs may be applied as receiving phases in passive sampling for the long-term water monitoring of PAHs and pharmaceuticals in water. In this paper, the concept of passive sampling with ILs (PASSIL applied as receiving phases) was continued and developed using phosphonium-, imidazolium-, and morpholinium-cation-based ILs. The target group of analytes was pharmaceuticals which represent one of the most common categories of water contaminants. Fourteen-day-long extractions using various ILs were performed in stirred conditions at a constant temperature (20 °C). The best extraction efficiency was achieved for trihexyl(tetradecyl)phosphonium dicyanamide ([P666-14][N(CN)₂]). For this preliminary calibration, the sampling rates were calculated for each sulfonamide. Once again, selectivity was observed in passive sampling using [P666-14][N(CN)₂]. Therefore, PASSIL is seen as a very promising method for pharmaceutical monitoring in water.

Detection and quantification of acidic drug residues in South African surface water using gas chromatography-mass spectrometry

A method was optimized for derivatization, separation, detection and quantification of salicylic acid, acetylsalicylic acid, nalidixic acid, ibuprofen, phenacetin, naproxen, ketoprofen, meclofenamic acid and diclofenac in surface water using gas chromatography-mass spectrometry. For most of the acidic drugs, recovery was in the range 60-110% and the percent standard deviation was below 15% for the entire method, with limits of detection ranging from 0.041 to 1.614 μg L^-1. The developed method was applied in the analysis of acidic drugs in Umgeni River system, KwaZulu-Natal South Africa. All of the selected acidic drugs were detected and quantified, their concentration in Umgeni River system ranged from 0.0200 to 68.14 μg L^-1.

Occurrence patterns of pharmaceutical residues in wastewater, surface water and groundwater of Nairobi and Kisumu city, Kenya

Emerging organic contaminants have not received a lot of attention in developing countries, particularly Africa, although problems regarding water quantity and quality are often even more severe than in more developed regions. This study presents general water quality parameters as well as unique data on concentrations and loads of 24 pharmaceuticals including antibiotic, anti(retro)viral, analgesic, anti-inflammatory and psychiatric drugs in three wastewater treatment plants, three rivers and three groundwater wells in Nairobi and Kisumu. This allowed studying removal efficiencies in wastewater treatment, identifying important sources of pharmaceutical pollution and distinguishing dilution effects from natural attenuation in rivers. In general, antiretrovirals and antibiotics, being important in the treatment of common African diseases such as HIV and malaria, were in all matrices more prevalent as compared to the Western world. Wastewater stabilization ponds removed pharmaceuticals with an efficiency between 11 and 99%. Despite this large range, a different removal is observed for a number of compounds, as compared to more conventional activated sludge systems. Total concentrations in river water (up to 320 μg L(-1)) were similar or exceeded concentrations in untreated wastewater, with domestic discharges from slums, wastewater treatment plant effluent and waste dumpsites identified as important sources. In shallow wells situated next to pit latrines and used for drinking water, the recalcitrant antiretroviral nevirapine was measured at concentrations as high as 1-2 μg L(-1). Overall, distinct pharmaceutical contamination patterns as compared to the Western world can be concluded, which might be a trigger for further research in developing regions.

Occurrence and distribution pattern of acidic pharmaceuticals in surface water, wastewater, and sediment of the Msunduzi River, Kwazulu-Natal, South Africa

The paucity of information on the occurrence of pharmaceuticals in the environment in African countries led the authors to investigate 8 acidic pharmaceuticals (4 antipyretics, 3 antibiotics, and 1 lipid regulator) in wastewater, surface water, and sediments from the Msunduzi River in the province of KwaZulu-Natal, South Africa, using solid-phase extraction (SPE) and liquid chromatography-mass spectrometry (LC/MS). The method recoveries, limits of detection (LOD), and limits of quantification were determined. The method recoveries were 58.4% to 103%, and the LODs ranged between 1.16 ng/L and 29.1 ng/L for water and between 0.58 ng/g and 14.5 ng/g for sediment. The drugs were all present in wastewater and in most of the surface water and sediment samples. Aspirin was the most abundant pharmaceutical observed, 118 ± 0.82 μg/L in wastewater influent, and the most observed antibiotic was nalidixic acid (25.2-29.9 μg/L in wastewater); bezafibrate was the least observed. The distribution pattern of the antipyretic in water indicates more impact in suburban sites. The solid-liquid partitioning of the pharmaceuticals between sediment and water, measured as the distribution coefficient (log KD ) gave an average accumulation magnitude of 10× to 32× in sediments than in water. The downstream distribution patterns for both water and sediment indicate discharge contributions from wastewater, agricultural activities, domestic waste disposal, and possible sewer system leakages. Although concentrations of the pharmaceuticals were comparable with those obtained from some other countries, the contamination of the present study site with pharmaceuticals has been over time and continues at present, making effective management and control necessary.