Contamination of Surface Water and River Sediments by Antibiotic and Antiretroviral Drug Cocktails in Low and Middle-Income Countries: Occurrence, Risk and Mitigation Strategies

Hazards of antiviral contamination in water: Dissemination, fate, risk and their impact on fish

Antiviral drugs are a cornerstone in the first line of antiviral therapy and their demand rises consistently with increments in viral infections and successive outbreaks. The drugs enter the waters due to improper disposal methods or via human excreta following their consumption; consequently, many of them are now classified as emerging pollutants. Hereby, we review the global dissemination of these medications throughout different water bodies and thoroughly investigate the associated risk they pose to the aquatic fauna, particularly our vertebrate relative fish, which has great economic and dietary importance and subsequently serves as a major doorway to the human exposome. Our risk assessment identifies eleven such drugs that presently pose high to moderate levels of risk to the fish. The antiviral drugs are likely to induce oxidative stress, alter the behaviour, affect different physiological processes and provoke various toxicological mechanisms. Many of the compounds exhibit elevated bioaccumulation potential, while, some have an increased tendency to leach through soil and contaminate the groundwater. Eight antiviral medications show a highly recalcitrant nature and would impact the aquatic life consistently in the long run and continue to influence the human exposome. Thereby, we call for urgent ecopharmacovigilance measures and modification of current water treatment methods.

Ecological impact of pharmaceutical pollutants and options of river health improvements - A risk analysis-based approach

Pharmaceuticals are one of the emerging pollutants (EPs) in river waters across the world. Due to their toxic effects on aquatic organisms, they have drawn the global attention of the scientific community concerned with river ecosystems. This paper reviews the existing occurrence data for various pharmaceutical pollutants (PPs) reported in river waters in some part of the world and their ecological impacts. Using algae, macroinvertebrates (MI), and fish as biotic indicator groups in water to reflect river health conditions, an attempt has been made to assess the ecological risk due to the presence of PPs in the water environment. After ascertaining the predicted no-effect concentration (PNEC) of PPs for selected groups of aquatic organisms, the risk quotient (RQ) is estimated based on their measured environmental concentration (MEC). When MEC > PNEC and RQ > 1 for any of the biotic indicator, ecologically it is 'high risk' condition. The determination of PNEC uses a minimum assessment factor (AF) of 10 due to uncertainty in data over the no observed effect level (NOEL) or lowest observed effect level (LOEL). Accordingly, MEC 10 times higher than PNEC, (RQ = 10) represents a threshold risk concentration (RCT) beyond which adverse effects may start showing observable manifestations. In the present study, a new classification system of 'high risk' conditions for RQ = 1-10 has been proposed, starting from 'moderately high' to 'severely high'. For RQ > 10, the ecological condition of the river is considered 'impaired'. For river health assessment, in the present study, the whole range of physico-chemical characteristics of river water quality has been divided into three groups based on their ease of measurement and frequency of monitoring. Dissolved oxygen related parameters (DORPs), nutrients (NTs), and EPs. PPs represent EPs in this study. A framework for calculating separate indicator group score (IGS) and the overall river health index (RHI) has been developed to predict indicator group condition (IGC) and river health condition (RHC), respectively. Color-coded hexagonal pictorial forms representing IGC and RHC provide a direct visible perception of the existing aquatic environment and a scientific basis for prioritization of corrective measures in terms of treatment technology selection for river health improvements. The analyses indicate that many rivers across the world are under 'high risk' conditions due to PPs having MEC > PNEC and RQ > 1. Up to RCT, (where RQ = 10), the 'high risk' condition varies from 'moderately high' to 'severely high'. In many instances, RQ is found much more higher than 10, indicating that the ecological condition of river may be considered as 'impaired'. Algae is the most frequently affected group of biotic indicators, followed by MI and fish. A review of treatment methods for selection of appropriate technology to reduce the pollution load, especially PPs from the wastewater streams has been summarized. It appears that constructed wetlands (CWs) are at present the most suitable nature-based solutions, particularly for the developing economies of the world, to reduce the concentrations of PPs within limits to minimize the ecological impacts of pharmaceutical compounds on biotic indicators and restore the river health condition. Some suggestive design guidelines for the CWs have also been presented to initiate the process.

Environmental Drivers of Antimicrobial Resistance in Low and Middle-Income Countries: The Impacts of a Changing World

This letter highlights the impact of environmental drivers on antimicrobial resistance (AMR) in low and middle-income countries (LMICs) and highlights the need for a comprehensive approach to address this global health threat. Key factors, such as agricultural practices, wastewater treatment, and pollution, contribute to the development and spread of resistant pathogens. Utilizing the One Health approach, the paper emphasizes the importance of promoting responsible antimicrobial use, strengthening public health systems, investing in innovative research, and raising public awareness. By understanding and addressing these environmental drivers, we can work toward safeguarding global health and ensuring a sustainable future.

Assessing ecological responses to exposure to the antibiotic sulfamethoxazole in freshwater mesocosms

Antibiotics are a contaminant class of worldwide concern as they are frequently detected in aquatic ecosystems. To better understand the impacts of antibiotics on aquatic ecosystems, we conducted an outdoor mesocosm experiment in which aquatic communities were exposed to different concentrations of the antibiotic sulfamethoxazole (0, 0.15, 1.5, 15 and 150 μg/L). These concentrations include mean (0.15 μg/L) and maximum detected concentrations (15 and 150 μg/L) in aquatic ecosystems worldwide. Sulfamethoxazole was applied once a week for eight consecutive weeks to 1530 L outdoor mesocosms in the Netherlands, followed by an eight-week recovery period. We evaluated phytoplankton-, bacterial- and invertebrate responses during and after sulfamethoxazole exposure and assessed impacts on organic matter decomposition. Contrary to our expectations, consistent treatment-related effects on algal and bacterial communities could not be demonstrated. In addition, sulfamethoxazole did not significantly affect zooplankton and macroinvertebrate communities. However, some effects on specific taxa were observed, with an increase in Mesostoma flatworm abundance (NOEC of <0.15 μg/L). In addition, eDNA analyses indicated negative impacts on the insects Odonata at a sulfamethoxazole concentration of 15 μg/L. Overall, environmentally relevant sulfamethoxazole concentration did not result in direct or indirect impairment of entire aquatic communities and ecological processes in our mesocosms. However, several specific macroinvertebrate taxa demonstrated significant (in)direct effects from sulfamethoxazole. Comparison of the results with the literature showed inconsistent results between studies using comparable, environmentally relevant, concentrations. Therefore, our study highlights the importance of testing the ecological impacts of pharmaceuticals (such as sulfamethoxazole) across multiple trophic levels spanning multiple aquatic communities, to fully understand its potential ecological threats.

Spatio-temporal distribution and source identification of antibiotics in suspended matter in the Fen River Basin

In this study, 26 typical antibiotics in the suspended matter of the Fen River basin were analyzed during the wet and dry seasons, and the main sources of antibiotic contamination were further identified. The results showed that the concentrations of antibiotics in the suspended matter varied seasonally. Sixteen antibiotics were detected in the suspended matter during the wet season with an average concentration of 463.56 ng/L. However, a total of 21 antibiotics were detected in the dry season, with an average concentration of 106.00 ng/L. The concentration of chloramphenicol antibiotics was outstanding in the wet season and dry season. The spatial distribution of the antibiotics in suspended matter showed little spatial discrepancy during the wet season. During the dry season, nevertheless, the concentration was higher upstream than midstream and downstream. The main sources of antibiotics in the Fen River Basin were livestock and poultry breeding, wastewater from wastewater treatment plants (WWTPs), agricultural drainage, domestic sewage, and pharmaceutical wastewater. Wastewater from WWTPs and domestic sewage were identified as two primary sources in the suspended matter during the wet season, with wastewater from WWTPs contributing the most accounting for 37%. While the most significant source of antibiotics in the suspended matter in the dry season was pharmaceutical wastewater, accounting for 36%. In addition, the contribution proportion of sources for antibiotics exhibited discrepant spatial distribution characteristics. In the wet season, wastewater from WWTPs dominated in the upstream and midstream, and livestock and poultry breeding was prominent in the midstream and downstream. Pharmaceutical wastewater was the main source in the midstream and downstream regions during the dry season.

Electrooxidation of amoxicillin in aqueous solution with graphite electrodes: Optimization of degradation and deciphering of byproducts using HRMS

Contaminants of emerging concern (CECs) such as antibiotics have become a matter of worry in aquatic environments worldwide. Their presence in the environment has been increasing due to the inability of conventional wastewater and water treatments to annihilate them. Hence, attempts have been made to remove CECs using electrochemical oxidation (EO). Present study employed the low cost, active carbon based graphite sheet electrodes as anode and cathode to oxidize and degrade Amoxicillin (AMOX)- a β-lactum thiazolidine antibiotic. Optimization studies found pH 9, 45 mA cm-2, 81 cm2 electrode surface area, 6 mM electrolyte concentration and 60 min treatment time to be optimal for AMOX removal. Studies with varying concentrations of AMOX (20 mg L-1, 30 mg L-1 and 40 mg L-1) found that increase in concentrations of AMOX require higher current densities and treatment time for better TOC removal. High performance liquid chromatography photo diode array (HPLC-PDA) studies found 94% removal for 40 mg L-1 of AMOX at optimal conditions with 90% COD and 46% TOC removal. High resolution mass spectrometry (HRMS) studies using Ultra performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-Q-ToF-MS) identified major degradation mechanisms to be hydroxylation, β-lactum ring cleavage, breakage of thiazolidine ring chain from the aromatic ring and piperazinyl ring formation. The final byproducts of AMOX oxidation were carboxylic acids.

Occurrence, Bioaccumulation, Metabolism and Ecotoxicity of Fluoroquinolones in the Aquatic Environment: A Review

In recent years, there has been growing concern about antibiotic contamination in water bodies, particularly the widespread presence of fluoroquinolones (FQs), which pose a serious threat to ecosystems due to their extensive use and the phenomenon of "pseudo-persistence". This article provides a comprehensive review of the literature on FQs in water bodies, summarizing and analyzing contamination levels of FQs in global surface water over the past three years, as well as the bioaccumulation and metabolism patterns of FQs in aquatic organisms, their ecological toxicity, and the influencing factors. The results show that FQs contamination is widespread in surface water across the surveyed 32 countries, with ciprofloxacin and norfloxacin being the most heavy contaminants. Furthermore, contamination levels are generally higher in developing and developed countries. It has been observed that compound types, species, and environmental factors influence the bioaccumulation, metabolism, and toxicity of FQs in aquatic organisms. FQs tend to accumulate more in organisms with higher lipid content, and toxicity experiments have shown that FQs exhibit the highest toxicity to bacteria and the weakest toxicity to mollusk. This article summarizes and analyzes the current research status and shortcomings of FQs, providing guidance and theoretical support for future research directions.

Decadal Assessment of Microplastics, Pharmaceuticals, and Pesticides as Contaminants of Emerging Concern in Kenya's Surface Waters: A Review

Studies investigating microplastics, pharmaceuticals, and pesticides as contaminants of emerging concern (CECs) in surface water sources in Kenya are reviewed. Contaminants of emerging concern are chemicals that have recently been discovered that may pose a threat to the environment, aquatic life, and human life. Microplastics in surface waters range from 1.56 to as high as 4520 particles/m3 , with high concentrations recorded in coastal waters. The dominant microplastics are fibers, fragments, and films, with foams, granules, and pellets making up only a small percentage. The main source of pharmaceuticals in water sources is not wastewater-treatment plants but rather raw untreated sewage because high concentrations are found near informal settlements with poor sewage connectivity. Antibiotics are detected in the range of the limit of quantification to 320 μg/L, with sulfamethoxazole, trimethoprim, and ciprofloxacin being the most abundant antibiotics. The high frequency of detection is attributed to the general misuse of antibiotics in the country. A health risk assessment indicated that only ciprofloxacin and acetaminophen posed noncarcinogenic health risks in the Ndarugo River and Mombasa periurban creeks, respectively. Similarly, the detection of antiretroviral drugs, mainly lamivudine, nevirapine, and zidovudine, is associated with human immunodeficiency virus prevalence in Kenya. In the Lake Naivasha, Nairobi River, and Lake Victoria basins, frequently detected organochloride pesticides (OCPs) are methoxychlor, alachlor, endrin, dieldrin, endosulfan, endosulfan sulfate, α-hexachlorocyclohexane (α-HCH), γ-HCH, and dichlorodiphenyltrichloroethane (DDT), some of which occur above permissible concentrations. The presence of DDT in some sites translates to illegal use or historical application. The majority of individual OCPs posed no noncarcinogenic health risk, except dieldrin and aldrin which had a hazard quotient >1 in two sites. Therefore, more surveying and regular monitoring in different regions in Kenya concerning CECs is essential to determine the spatial variability and effective measures to be taken to reduce pollution. Environ Toxicol Chem 2023;42:2105-2118. © 2023 SETAC.

The pit latrine paradox in low-income settings: A sanitation technology of choice or a pollution hotspot?

Pit latrines are widely promoted to improve sanitation in low-income settings, but their pollution and health risks receive cursory attention. The present narrative review presents the pit latrine paradox; (1) the pit latrine is considered a sanitation technology of choice to safeguard human health, and (2) conversely, pit latrines are pollution and health risk hotspots. Evidence shows that the pit latrine is a 'catch-all' receptacle for household disposal of hazardous waste, including; (1) medical wastes (COVID-19 PPE, pharmaceuticals, placenta, used condoms), (2) pesticides and pesticide containers, (3) menstrual hygiene wastes (e.g., sanitary pads), and (4) electronic wastes (batteries). Pit latrines serve as hotspot reservoirs that receive, harbour, and then transmit the following into the environment; (1) conventional contaminants (nitrates, phosphates, pesticides), (2) emerging contaminants (pharmaceuticals and personal care products, antibiotic resistance), and (3) indicator organisms, and human bacterial and viral pathogens, and disease vectors (rodents, houseflies, bats). As greenhouse gas emission hotspots, pit latrines contribute 3.3 to 9.4 Tg/year of methane, but this could be an under-estimation. Contaminants in pit latrines may migrate into surface water, and groundwater systems serving as drinking water sources and pose human health risks. In turn, this culminates into the pit latrine-groundwater-human continuum or connectivity, mediated via water and contaminant migration. Human health risks of pit latrines, a critique of current evidence, and current and emerging mitigation measures are presented, including isolation distance, hydraulic liners/ barriers, ecological sanitation, and the concept of a circular bioeconomy. Finally, future research directions on the epidemiology and fate of contaminants in pit latrines are presented. The pit latrine paradox is not meant to downplay pit latrines' role or promote open defaecation. Rather, it seeks to stimulate discussion and research to refine the technology to enhance its functionality while mitigating pollution and health risks.

Antiviral drugs in wastewater are on the rise as emerging contaminants: A comprehensive review of spatiotemporal characteristics, removal technologies and environmental risks

Antiviral drugs (ATVs) are widely used to treat illnesses caused by viruses. Particularly, ATVs were consumed in such large quantities during the pandemic that high concentrations were detected in wastewater and aquatic environment. Since ATVs are not fully absorbed by the human or animal body, this results in large amounts of them being discharged into the sewage through urine or feces. Most ATVs can be degraded by microbes at wastewater treatment plants (WWTPs), while some ATVs either require deep treatment to reduce concentration and toxicity. Parent and metabolites residing in effluent posed a varying degree of risk when entering the aquatic environment, while increasing the potential of natural reservoirs for environmentally acquired antiviral drug resistance potential. There is a rising research on the behavior of ATVs in the environment has surged since the pandemic. In the context of multiple viral diseases worldwide, especially during the current COVID-19 pandemic, a comprehensive assessment of the occurrence, removal, and risk of ATVs is urgently needed. This review aims to discuss the fate of ATVs in WWTPs from various regions in the world with wastewater as the main analyzing object. The ultimate goal is to focus on ATVs with high ecological impact and regulate their use or develop advanced treatment technologies to mitigate the risk to the environment.

Zirconium ferrite incorporated zeolitic imidazolate framework-8: a suitable photocatalyst for degradation of dopamine and sulfamethoxazole in aqueous solution

The complete removal of pharmaceutical wastes from polluted water systems is a global challenge. Therefore, this study incorporates zirconium ferrite (ZrFe2O4) into zeolitic imidazolate framework-8 (ZIF-8) to form ZrFe2O4@ZIF-8. The ZrFe2O4@ZIF-8 is a photocatalyst for removing dopamine (DOP) and sulfamethoxazole (SMX) from an aqueous solution. The scanning electron micrograph revealed the surfaces of ZrFe2O4 and ZrFe2O4@ZIF-8 to be heterogeneous with irregularly shaped and sized particles. The transmission electron micrograph (TEM) images of ZrFe2O4 and ZrFe2O4@ZIF-8 showed an average particle size of 24.32 nm and 32.41 nm, respectively, with a bandgap of 2.10 eV (ZrFe2O4@ZIF-8) and 2.05 eV (ZrFe2O4). ZrFe2O4@ZIF-8 exhibited a better degradation capacity towards DOP and SMX than ZrFe2O4. ZrFe2O4@ZIF-8 expressed a complete (100%) degradation of DOP and SMX during the photodegradation process. Interestingly, the process involved both adsorption and photocatalytic degradation simultaneously. ZrFe2O4@ZIF-8 demonstrated high stability with a consistent regeneration capacity of 98.40% for DOP and 94.00% for SMX at the 10th cycle of treatment in a process described by pseudo-first-order kinetics. The study revealed ZrFe2O4@ZIF-8 as a promising photocatalyst for the purification of DOP and SMX-contaminated water systems.

Levels and ecological risk of pharmaceuticals in River Sosiani, Kenya

The continued frequent detection of pharmaceuticals in the environment is of major concern due to potential human and ecological risks. This study evaluated 30 antibiotics from 8 classes: sulphonamides (SAs), penicillins (PNs), fluoroquinolones (FQs), macrolides (MLs), lincosamides (LINs), nitroimidazoles (NIs), diaminopyrimidines (DAPs), salfones and 4 anthelmintics benzimidazoles (BZs) in surface water and sediments from River Sosiani in Eldoret, Kenya. Samples were collected during the wet and dry seasons and subjected to solid phase extraction using HLB cartridges. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was used for the simultaneous quantification of the compounds. Chromatographic separation was on a reversed-phase Zorkax Eclipse Plus C18 column eluted in a gradient program and compounds detected by mass spectrometer operated in a positive electrospray ionization (+ ESI) mode. Twenty-eight antibiotics were detected in water where 22 had a 100% detection frequency and the remaining 4 showed detection frequencies ranging from 5 to 47%. Three BZs had a 100% detection frequency. Detectable concentrations of the pharmaceuticals in water ranged between 0.1 and 247 ng L^-1 and 0.01 and 974 µg kg^-1 in the sediments. The sulfonamide, sulfamethoxazole, had the highest concentration in water (247 ng L^-1), whereas penicillin G showed the highest concentrations in sediments (414-974 µg kg^-1). Quantified pharmaceuticals decreased in the order SAs > DAPs > FQs > ATs > PNs ≈ MCs ≈ LNs > NIs in water, and followed the order PNs > BZs > FQs > MLs > DAPs ≈ LNs > NIs > SAs in sediments. Risk quotients (RQ_w) showed that sulfamethoxazole and ciprofloxacin were of high ecological risk in the surface water (RQ_w values of 1.11 and 3.24, respectively), whereas penicillin V, ampicillin, penicillin G, norfloxacin, enrofloxacin, erythromycin, tylosin, and lincomycin were of medium ecological risk in the aquatic system. The findings show high prevalence of pharmaceuticals in surface water and sediments and are therefore potential ecological hazards. Such information is vital when devising mitigation strategies.

Pristina longiseta reproduction test: chronic exposure to environmental contaminants

Aquatic worms are considered a suitable group to evaluate the effects of contaminants on the environment, although one of the main challenges is to use the species of local occurrence. Recently, Pristina longiseta was suggested to be used in acute bioassays. In this context, this study aimed to establish a chronic exposure for ecotoxicological bioassays using the cosmopolitan species of occurrence in Brazilian freshwater P. longiseta. Firstly, we tested three exposure times (4, 7, and 10 days) under the presence or absence of aeration for reproduction outputs. After determining the best configuration (7 days without aeration), we assessed the effects of the chronic exposures using the standardized reference substance potassium chloride (KCl), the antibiotic sulfamethoxazole (SMX), the flame retardant tetrabromobisphenol A (TBBPA), and the sugarcane vinasse. Our results showed suitability for applying the chronic exposure using P. longiseta and indicated the sensitivity of the offspring to KCl (EC50-7d = 0.51 g/L). Sulfamethoxazole and TBBPA caused a significant decrease in the offspring of P. longiseta (EC50-7d = 59.9 µg/L and < 62.5 µg/L, respectively). Sugarcane vinasse showed high toxicity for the species, and 4.26% of vinasse was calculated as EC50-7d. Therefore, the described protocol was successfully applied as an ecotoxicological bioassay to evaluate the effects of environmental contaminants on the reproduction rate of the freshwater worm P. longiseta.

The screening of emerging micropollutants in wastewater in Sol Plaatje Municipality, Northern Cape, South Africa

Although pollutants pose environmental and human health risks, the majority are not routinely monitored and regulated. Organic pollutants emanate from a variety of sources, and can be classified depending on their chemistry and environmental fate. Classification of pollutants is important because it informs fate processes and apposite removal technologies. The occurrence of emerging contaminants (ECs) in water bodies is a source of environmental and human health concern globally. Despite being widely reported, data on the occurrence of ECs in South Africa are scarce. Specifically, ECS in wastewater in the Northern Cape in South Africa are understudied. In this study, various ECs were screened in water samples collected from three wastewater treatment plants (WWTPs) in the province. The ECs were detected using liquid chromatography coupled to high resolution Orbitrap mass spectrometry following Oasis HLB solid-phase extraction. The main findings were: (1) there is a wide variety of ECs in the WWTPs, (2) physico-chemical properties such as pH, total dissolved solids, conductivity, and dissolved organic content showed reduced values in the outlet compared to the inlet which confirms the presence of less contaminants in the treated wastewater, (3) specific ultraviolet absorbance of less than 2 was observed in the WWTPs samples, suggesting the presence of natural organic matter (NOM) that is predominantly non-humic in nature, (4) most of the ECs were recalcitrant to the treatment processes, (5) pesticides, recreational drugs, and analgesics constitute a significant proportion of pollutants in wastewater, and (6) NOM removal ranged between 35 and 90%. Consequently, a comprehensive database of ECs in wastewater in Sol Plaatje Municipality was created. Since the detected ECs pose ecotoxicological risks, there is a need to monitor and quantify ECs in WWTPs. These data are useful in selecting suitable monitoring and control strategies at WWTPs.

Emerging technologies for enhanced removal of residual antibiotics from source-separated urine and wastewaters: A review

Antibiotic residues are of significant concern in the ecosystem because of their capacity to mediate antibiotic resistance development among environmental microbes. This paper reviews recent technologies for the abatement of antibiotics from human urine and wastewaters. Antibiotics are widely distributed in the aquatic environment as a result of the discharge of municipal sewage. Their existence is a cause for worry due to the potential ecological impact (for instance, antibiotic resistance) on bacteria in the background. Numerous contaminants that enter wastewater treatment facilities and the aquatic environment, as a result, go undetected. Sludge can act as a medium for some chemicals to concentrate while being treated as wastewater. The most sewage sludge that has undergone treatment is spread on agricultural land without being properly checked for pollutants. The fate of antibiotic residues in soils is hence poorly understood. The idea of the Separation of urine at the source has recently been propagated as a measure to control the flow of pharmaceutical residues into centralized wastewater treatment plants (WWTPs). With the ever increasing acceptance of urine source separation practices, visibility and awareness on dedicated treatement technologies is needed. Human urine, as well as conventional WWTPs, are point sources of pharmaceutical micropollutants contributing to the ubiquitous detection of pharmaceutical residues in the receiving water bodies. Focused post-treatment of source-separated urine includes distillation and nitrification, ammonia stripping, and adsorption processes. Other reviewed methods include physical and biological treatment methods, advanced oxidation processes, and a host of combination treatment methods. All these are aimed at ensuring minimized risk products are returned to the environment.

Do anti-HIV drugs pose a threat to photosynthetic microorganisms?

We investigated the occurrence and risk assessment of three anti-HIV drugs [(tenofovir (TNF), lamivudine (LMV) and efavirenz (EFV)] in urban rivers from Curitiba (Brazil), as well as the individual and combined effects of their environmental representative concentrations on the freshwater periphytic species Synechococcus elongatus (Cyanobacteria) and Chlorococcum infusionum (Chlorophyta). The three studied drugs, except TNF, were found in 100% of the samples, and concentrations in samples ranged from 165 to 412 ng TNF L^-1, 173-874 ng LMV L^-1 and 13-1250 ng EFV L^-1. Bioassays using artificial contaminated water showed that at environmental concentrations, TNF and LMV did not represent environmental risks to the studied photosynthetic organisms. However, EFV was shown to be toxic, affecting photosynthesis, respiration, and oxidative metabolism. The studied drugs demonstrated interactive effects. Indeed, when submitted to the combination of TNF and LMV, decreased photosynthesis was observed in C. infusionum cells. Moreover, the toxic effects of EFV were amplified in both species when TNF and/or LMV were added to the media. The simultaneous presence of TNF, LMV and EFV in environmental matrices associated with their interactive effects, lead to increased toxicological effects of water contaminated by anti-HIV drugs and thus to an ecological threat to photosynthetic microorganisms.

Occurrence and Distribution of Antibiotics in the Water, Sediment, and Biota of Freshwater and Marine Environments: A Review

Antibiotics, as pollutants of emerging concern, can enter marine environments, rivers, and lakes and endanger ecology and human health. The purpose of this study was to review the studies conducted on the presence of antibiotics in water, sediments, and organisms in aquatic environments (i.e., seas, rivers, and lakes). Most of the reviewed studies were conducted in 2018 (15%) and 2014 (11%). Antibiotics were reported in aqueous media at a concentration of <1 ng/L−100 μg/L. The results showed that the highest number of works were conducted in the Asian continent (seas: 74%, rivers: 78%, lakes: 87%, living organisms: 100%). The highest concentration of antibiotics in water and sea sediments, with a frequency of 49%, was related to fluoroquinolones. According to the results, the highest amounts of antibiotics in water and sediment were reported as 460 ng/L and 406 ng/g, respectively. In rivers, sulfonamides had the highest abundance (30%). Fluoroquinolones (with an abundance of 34%) had the highest concentration in lakes. Moreover, the highest concentration of fluoroquinolones in living organisms was reported at 68,000 ng/g, with a frequency of 39%. According to the obtained results, it can be concluded that sulfonamides and fluoroquinolones are among the most dangerous antibiotics due to their high concentrations in the environment. This review provides timely information regarding the presence of antibiotics in different aquatic environments, which can be helpful for estimating ecological risks, contamination levels, and their management.

Sweep-Out of Tigecycline, Chlortetracycline, Oxytetracycline, and Doxycycline from Water by Carbon Nanoparticles Derived from Tissue Waste

Pharmaceutical pollution has pervaded many water resources all over the globe. The propagation of this health threat drew the researchers' concern in seeking an efficient solution. This study introduced toilet paper waste as a precursor for carbon nanoparticles (CRNPs). The TEM results showed a particle size range of 30.2 nm to 48.1 nm, the BET surface area was 283 m² g^-1, and the XRD pattern indicated cubical-graphite crystals. The synthesized CRNPs were tested for removing tigecycline (TGCN), chlortetracycline (CTCN), oxytetracycline (OTCN), and doxycycline (DXCN) via the batch process. The adsorption equilibrium time for TGCN, DXCN, CTCN, and OTCN was 60 min, and the concentration influence revealed an adsorption capacity of 172.5, 200.1, 202.4, and 200.0 mg g^-1, respectively. The sorption of the four drugs followed the PSFO, and the LFDM models indicated their high sorption affinity to the CRNPs. The adsorption of the four drugs fitted the multilayer FIM that supported the high-affinity claim. The removals of the four drugs were exothermic and spontaneous physisorption. The fabricated CRNPs possessed an excellent remediation efficiency for contaminated SW and GW; therefore, CRNPs are suggested for water remediation as low-cost sorbent.

Contribution of Illicit Drug Use to Pharmaceutical Load in the Environment: A Focus on Sub-Saharan Africa

Illicit drug abuse and addiction are universal issues requiring international cooperation and interdisciplinary and multisectoral solutions. These addictive substances are utilized for recreational purposes worldwide, including in sub-Saharan Africa. On the other hand, conventional wastewater treatment facilities such as waste stabilization ponds lack the design to remove the most recent classes of pollutants such as illicit drug abuse. As a result, effluents from these treatment schemes contaminate the entire ecosystem. Public health officials are concerned about detecting these pollutants at alarming levels in some countries, with potential undesirable effects on aquatic species and increased health hazards through exposure to contaminated waters or recycling treated or untreated effluents in agriculture. Contaminants including illicit substances enter the environment by human excreta following illegal intake, spills, or through direct dumping, such as from clandestine laboratories, when their manufacturer does not follow accepted production processes. These substances, like other pharmaceuticals, have biological activity and range from pseudopersistent to highly persistent compounds; hence, they persist in the environment while causing harm to the ecosystem. The presence of powerful pharmacological agents such as cocaine, morphine, and amphetamine in water as complex combinations can impair aquatic organisms and human health. These compounds can harm human beings and ecosystem health apart from their low environmental levels. Therefore, this article examines the presence and levels of illicit substances in ecological compartments such as wastewater, surface and ground waters in sub-Saharan Africa, and their latent impact on the ecosystem. The information on the occurrences of illicit drugs and their metabolic products in the sub-Saharan Africa environment and their contribution to pharmaceutical load is missing. In this case, it is important to research further the presence, levels, distribution, and environmental risks of exposure to human beings and the entire ecosystem.

Occurrence and ecotoxicity of sulfonamides in the aquatic environment: A review

Rapid population growth and increasing demand for animal protein food have led to a continuous increase in global utilization of antibiotic. Sulfonamides (SAs) are ubiquitous in aquatic environments and pose an ecological risk owing to their large consumption and strong environmental persistence. Hence, this review focuses on the recent publications on 12 different SAs and provides a detailed summary of selected antibiotic concentrations in various water systems. We evaluated the ecotoxicity of SAs on organisms at different trophic level organisms and the environmental risks regarding aquatic systems. The results indicated that SA antibiotics were ubiquitous in aquatic environments at concentrations ranging from ng/L to μg/L. According to the data using standard ecotoxicity bioassays, algae were the most susceptible aquatic organisms for selected antibiotics, followed by crustaceans and fish. The risk data suggested that some antibiotics, such as sulfadiazine (SDZ), sulfamethoxazole (SMX), and sulfamethazine (SMZ) pose a great risk to the aquatic system. Based on the present review, it is necessary to strengthen the research into their ecotoxicity to marine systems and the chronic toxicity of antibiotic mixtures.

Cytochrome P450 Inhibition by Antimicrobials and Their Mixtures in Rainbow Trout Liver Microsomes In Vitro

Antimicrobials are ubiquitous in the environment and can bioaccumulate in fish. In the present study, we determined the half-maximal inhibitory concentrations (IC50) of 7 environmentally abundant antimicrobials (ciprofloxacin, clarithromycin, clotrimazole, erythromycin, ketoconazole, miconazole, and sulfamethoxazole) on the cytochrome P450 (CYP) system in rainbow trout (Oncorhynchus mykiss) liver microsomes, using 7-ethoxyresorufin O-deethylation (EROD, CYP1A) and 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylation (BFCOD, CYP3A) as model reactions. Apart from ciprofloxacin and sulfamethoxazole, all antimicrobials inhibited either EROD or BFCOD activities or both at concentrations <500 µM. Erythromycin was the only selective and time-dependent inhibitor of BFCOD. Compared with environmental concentrations, the IC50s of individual compounds were generally high (greater than milligrams per liter); but as mixtures, the antimicrobials resulted in strong, indicatively synergistic inhibitions of both EROD and BFCOD at submicromolar (~micrograms per liter) mixture concentrations. The cumulative inhibition of the BFCOD activity was detectable even at picomolar (~nanograms per liter) mixture concentrations and potentiated over time, likely because of the strong inhibition of CYP3A by ketoconazole (IC50 = 1.7 ± 0.3 µM) and clotrimazole (IC50 = 1.2 ± 0.2 µM). The results suggest that if taken up by fish, the mixtures of these antimicrobials may result in broad CYP inactivation and increase the bioaccumulation risk of any other xenobiotic normally cleared by the hepatic CYPs even at biologically relevant concentrations. Environ Toxicol Chem 2022;41:663-676. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A recent advancement on nanomaterials for electrochemical sensing of sulfamethaoxole and its futuristic approach

Sulfamethoxazole (SMX) forms the high harmfulness and causing negative health impacts to well-being human and environment that found to be major drastic concern. It is subsequently important to keep in track for monitoring of SMX through convenient detecting devices which include the requirement of being minimal expense and potential for on location environmental applications. Nanomaterials based design has been proposed to determine the SMX antibiotic which in turn provides the solution for this issue. In spite of the critical advancement accomplished in research, further endeavors are yet to foster the progress on electrochemical sensors with the guide of various functional nanomaterials and guarantee the effective transportability for such sensors with improved coherence. Moreover, it has been noticed that, only few reports on electrochemical sensing of SMX detection using nanomaterials was observed. Hence an in-depth evaluation of electrochemical sensing systems using various nanomaterials for SMX detection was summarized in this review. Additionally this current review centers with brief presentation around SMX hazard evaluation followed by study on the current logical techniques to feature the importance for SMX detection. This review will provide the sum up view towards the future ideas of this field which assists in improving the detecting strategies for SMX detection.

HIV-antiretrovirals in river water from Gauteng, South Africa: Mixed messages of wastewater inflows as source

South Africa has the highest number of people living with the human immunodeficiency virus (HIV). High usage of HIV-antiretroviral drugs (ARVs) for the treatment of the acquired immunodeficiency syndrome (AIDS) leads to the presence of ARVs in the environment. Wastewater is a major contributor of pharmaceuticals in surface and drinking water as wastewater treatment plants (WWTPs) are not designed to remove these compounds. Pharmaceuticals in the environment pose risks and the effects of ARVs on non-target organisms are largely unknown. The concentrations of ARVs in surface water upstream and downstream from WWTPs in rivers were determined. The samples were extracted by solid-phase extraction and analysed by using liquid chromatography coupled with a quadrupole time-of-flight mass spectrometer. Five ARVs were quantified, mostly in downstream samples of the WWTPs, indicating wastewater as a source of ARVs, but this was not apparent in all cases. Nevirapine, lopinavir, and efavirenz were frequently detected; the highest concentrations being lopinavir and efavirenz at 38 μg/L and 24 μg/L, respectively. Aquatic ecosystems are at risk due to the constant input of pharmaceuticals that include large amounts of everyday use and the release of ARVs. This study highlights the potential of increased water pollution worldwide should more people consume increased quantities of pharmaceuticals.

Antiretroviral Drugs in African Surface Waters: Prevalence, Analysis, and Potential Remediation

The sources, ecotoxicological impact, and potential remediation strategies of antiretroviral drugs (ARVDs) as emerging contaminants in surface waters are reviewed based on recent literature. The occurrence of ARVDs in water bodies raises concern because many communities in Africa depend on rivers for water resources. Southern Africa is a potential hotspot regarding ARVD contamination due to relatively high therapeutic application and detection thereof in water bodies. Efavirenz and nevirapine are the most persistent in effluents and are prevalent in surface water based on environmental concentrations. Whereas the highest concentration of efavirenz reported in Kenya was 12.4 µg L^-1 , concentrations as high as 119 and 140 µg L^-1 have been reported in Zambia and South Africa, respectively. Concentrations of ARVDs ranging from 670 to 34 000 ng L^-1 (influents) and 540 to 34 000 ng L^-1 (effluents) were determined in wastewater treatment plants in South Africa, compared with Europe, where reported concentrations range from less than limit of detection (LOD) to 32 ng L^-1 (influents) and less than LOD to 22 ng L^-1 (effluents). The present African-based review suggests the need for comprehensive toxicological and risk assessment of these emerging pollutants in Africa, with the intent of averting environmental hazards and the development of sustainable remediation strategies. Environ Toxicol Chem 2022;41:247-262. © 2021 SETAC.

Spatio-temporal distribution of pharmaceutically active compounds in the River Cauvery and its tributaries, South India

Pharmaceutically active compounds (PhACs) present in the environment are a great threat to human well-being and the ecosystem. Eventhough recognized as the pharmacy of the world", studies addressing the distribution of PhACs in the Indian environment are scarce. Hence, in the current study, selected PhACs, heavy metals (HMs), and physicochemical parameters (PCPs) were measured from the surface waters of the River Cauvery during the pre- and post-monsoon. PhACs such as caffeine, carbamazepine, and diclofenac were detected in most samples, whereas topiramate, ibuprofen, and verapamil were found only in few stations. In contrast, the distribution of ciprofloxacin, atenolol, and isoprenaline was strongly influenced by the seasonal pattern (p < 0.05). PhACs such as loperamide, glafenine, erythromycin, and gemfibrozil were not detected during the study. Distribution of PhACs based on average concentration (ng/L) are, CBZ (205.62) > CAF (114.09) > DCF (28.51) > CIP (25.23) > ATL (18.86) > IPL (13.91) > PPL (11.26) > TCS (10.39) > IBF (7.34) > TPT (3.09) > VPL (1.16). Bivariate and multivariate statistical analyses have revealed a positive correlation expressed by the majority of the PhACs with PCPs (COD, TOC), nutrients (TN, TP), and HMs (Pb, Mn, Ni) in the range from 0.540** to 0.961**(p < 0.01). Whereas, DO revealed negative correlation with most of the parameters in the range from -0.559** to -0.831** (p < 0.01). A high average concentration of PhACs was recorded in the upstream (52.08 ng/L) and wastewater discharge points (55.60 ng/L). Further, the environmental risk assessment study has identified the higher risk exhibited by TCS (RQ: 3.29) and CAF (RQ: 38.82) on algae and Daphnia respectively. The study portrays the distribution of emerging contaminants in the River Cauvery and its tributaries and also delivers preliminary data about the distribution of isoprenaline, topiramate, verapamil, and perindopril in the Indian freshwater system.

Occurrence and Effects of Antimicrobials Drugs in Aquatic Ecosystems

Currently, thanks to the development of sensitive analytical techniques, the presence of different emerging pollutants in aquatic ecosystems has been evidenced; however, most of them have not been submitted to any regulation so far. Among emerging contaminants, antimicrobials have received particular attention in recent decades, mainly due to the concerning development of antibiotic resistance observed in bacteria, but little is known about the toxicological and ecological impact that antimicrobials can have on aquatic ecosystems. Their high consumption in human and veterinary medicine, food-producing animals and aquaculture, as well as persistence and poor absorption have caused antimicrobials to be discharged into receiving waters, with or without prior treatment, where they have been detected at ng-mg L−1 levels with the potential to cause effects on the various organisms living within aquatic systems. This review presents the current knowledge on the occurrence of antimicrobials in aquatic ecosystems, emphasizing their occurrence in different environmental matrixes and the effects on aquatic organisms (cyanobacteria, microalgae, invertebrates and vertebrates).

Contrasting Effects of Environmental Concentrations of Sulfonamides on Microbial Heterotrophic Activities in Freshwater Sediments

The sulfonamide antibiotics sulfamethoxazole (SMX) and sulfamethazine (SMZ) are regularly detected in surface sediments of contaminated hydrosystems, with maximum concentrations that can reach tens of μg kg^–1 in stream and river sediments. Little is known about the resulting effects on the exposed benthic organisms. Here we investigated the functional response of stream sediment microbial communities exposed for 4 weeks to two levels of environmentally relevant concentrations of SMX and SMZ, tested individually. To this end, we developed a laboratory channel experiment where natural stream sediments were immersed in water contaminated with nominal environmental concentrations of 500 and 5,000 ng L^–1 of SMX or SMZ, causing their accumulation in surface sediments. The mean maximum concentrations measured in the sediment (about 2.1 μg SMX kg^–1 dw and 4.5 μg SMZ kg^–1 dw) were consistent with those reported in contaminated rivers. The resulting chronic exposure had various effects on the functional potential of the sediment microbial communities, according to the substance (SMX or SMZ), the type of treatment (high or low) and the measured activity, with a strong influence of temporal dynamics. Whereas the SMZ treatments resulted in only transient effects on the five microbial activities investigated, we observed a significant stimulation of the β-glucosidase activity over the 28 days in the communities exposed to the high concentration of SMX. Together with the stimulation of aerobic respiration at low SMX concentrations and the reduced concentration observed in the last days, our results suggest a potential biodegradation of sulfonamides by microbial communities from sediments. Given the key functional role of surface sediment microbial communities in streams and rivers, our findings suggest that the frequently reported contamination of sediments by sulfonamides is likely to affect biogeochemical cycles, with possible impact on ecosystem functioning.

Strong links between load and manure and a comprehensive risk assessment of veterinary antibiotics with low KOW in intensive livestock farming watersheds

Various veterinary antibiotics (VAs) are used in large quantities as an essential component for intensive livestock farming, and can flow into the environment from various pollution sources. In this study, VAs in surface water and groundwater in the Gwangcheon stream watershed, an intensive livestock farming area in Korea, were analyzed using ultra-high-performance liquid chromatograph-quadrupole orbitrap high-resolution mass spectrometer with online solid phase extraction. Although the selected VAs are relatively mobile and have low K_OW values it is significant to assess their fates and ecological risks in the environment. The concentration of VAs in the surface water was higher than that in groundwater by approximately 23-fold, indicating that the former were directly introduced from pollution sources such as livestock manure. An analysis of the correlation between livestock manure production and the residuals of VAs in the stream showed a high linearity (R² > 0.70), confirming that livestock excreta significantly contributed to the VAs in the watershed. A combined evaluation of environmental behaviors and ecological risks of VAs was performed for the first time using persistence, bioaccumulation potential, and toxicity properties and risk quotient values of VAs. Trimethoprim showed persistence and a potential impact on the ecosystem. The cumulative risk quotient values at one sampling point exceeded 1 indicating that several VAs can cumulatively cause local risk. The risk assessment method considering pollution sources, different locations, and correlation analysis applied in this study will be useful in evaluating the impacts of trace pollutants in watersheds.

Histopathological changes in Oreochromis mossambicus (Peters, 1852) ovaries after a chronic exposure to a mixture of the HIV drug nevirapine and the antibiotics sulfamethoxazole and trimethoprim

The burden of the human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) infection has transformed the African continent into a major consumer of antiretrovirals (ARVs) drugs. In addition to HIV burden, the African continent has also a high incidence of tuberculosis (TB) and has been experiencing recurring outbreaks of several other viral, bacterial, and parasitic epidemic diseases. The novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2 or Covid-19) pandemic outbreak is adding to the continent's infectious diseases burden as experts are predicting that it will be here for a long time. One of the consequences of these infectious diseases is that antiviral and antibiotic compounds have become some of the most consumed pharmaceuticals on the continent. Many of these drugs have been frequently detected in surface waters across Africa. There is limited information available on the adverse effects of the mixtures of different types of pharmaceuticals in African aquatic environments on fish reproduction. The present study investigated the effects of the ARV drug nevirapine (NVP - 1.48 and 3.74 μg/L) and its mixture with the antibiotic sulfamethoxazole (3.68 μg/L) and trimethoprim (0.87 μg/L) on O. mossambicus gonads using histopathological endpoints as biomarkers. The fish (n = 52) were exposed for 30 days in a static renewal system. Female O. mossambicus exposed to nevirapine (3.74 μg/L) and to NVP - antibiotic mixture recorded higher ovary indices. Statistically significant differences were found in female ovary indices between the fish exposed to NVP (3.74 μg/L) and the control fish (p = 0.002) as well as between the fish exposed to the NVP - antibiotic mixture and the control fish (p = 0.009). The main observed histopathological changes in the ovaries were increased vitellogenic oocyte atresia and vacuolation of the interstitial tissue in the fish exposed to NVP - antibiotic mixture. It is evident that the presence of NVP - antibiotics mixture in water triggered the observed histopathology in female fish ovaries. The detected abnormal high rate of atretic oocytes could result in impaired fish reproduction.

Rapid and cost-effective multiresidue analysis of pharmaceuticals, personal care products, and antifouling booster biocides in marine sediments using matrix solid phase dispersion

Currently, there are many contaminants of concern that need to be accurately determined to help assess their potential environmental hazard. Despite their increasing interest, yet few environmental occurrence data exist, likely because they are present at low levels and in very complex matrices. Therefore, multiresidue analytical methods for their determination need to be highly sensitive, selective, and robust. Particularly, due to the trace levels of these chemicals in the environment, an extensive extraction procedure is required before determination. This work details the development of a fast and cheap vortex-assisted matrix solid-phase dispersion-high performance liquid chromatography tandem-mass spectrometry (VA-MSPD-HPLC-MS/MS) method for multiresidue determination of 59 contaminants of emerging concern (CECs) including pharmaceuticals, personal care products, and booster biocides, in sediment. The validated method provided high sensitivity (0.42-36.8 ngg^-1 dw quantification limits), wide and good linearity (r² > 0.999), satisfactory accuracy (60-140%), and precision below 20% for most target analytes. In comparison with previous methods, relying on traditional techniques, the proposed method demonstrated to be more environmentally friendly, cheaper, simpler, and faster. The method was applied to monitor the occurrence of these compounds in sediments collected in Brazil, using only 2 g dw sediment samples, free-solid support, and 5 mL methanol as extraction solvent. The UV filter avobenzone, the UV stabilizer and antifreeze methylbenzotriazole, the preservative methylparaben, the fluoroquinolone antibiotic ciprofloxacin, and the biocides irgarol and 4,5-dichloro-2-octyl-4-isothiazolin-3-one were determined at concentrations in the range 1.44-69.7 ngg^-1 dw.