Assessing the risk associated with the presence of emerging organic contaminants in sludge-amended soil: A country-level analysis

Study on the fate of per- and polyfluoroalkyl substances during thermophilic anaerobic digestion of sewage sludge and the role of granular activated carbon addition

Limited information is available on the removal of per- and polyfluoroalkyl substances (PFAS) in anaerobic digestion (AD). Τhe fate of six PFAS was studied in thermophilic bioreactors in the presence of granular activated carbon (GAC) and voltage application. Reactors with GAC exhibited lower concentrations of volatile fatty acids and higher methane production compared to those with and without the application of voltage. Analysis of PFAS in dissolved and solid phase showed that their distribution was dependent on perfluorocarbon chain length and functional group. Mass balances showed that PFAS were not removed during conventional AD or after applying voltage; however, significant removal (up to 61 ± 8 %) was observed in bioreactors with GAC for perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonate (PFOS). Biomass characterization showed that in these bioreactors, the relative abundance of Acinetobacter and Pseudomonas was higher, indicating their potential role in PFAS biotransformation.

Selection of pharmaceuticals of concern in reclaimed water for crop irrigation in the Mediterranean area

The reuse of reclaimed water in agriculture is being fostered in areas suffering from water scarcity. However, water pollutants can compromise food safety and pose a risk for the environment. This study aims to select the pharmaceutical compounds worth monitoring and investigating when reclaimed water is used for tomato and lettuce irrigation. A comprehensive study was first conducted to identify the pharmaceuticals frequently detected in secondary wastewater effluents in Catalonia (Northeast Spain). Priority pharmaceuticals were further selected based on their occurrence in secondary effluents, persistence (removal in conventional treatment), bioaccumulation potential, toxicity for aquatic organisms, and the risks they pose to the terrestrial environment and human health (through the consumption of crops). Out of the 47 preselected priority compounds, six could pose a risk to organisms living in soil irrigated with reclaimed water and seven could be potentially taken up by the crops. Nonetheless, no risk for human consumption was foreseen.

The occurrence of heavy metals and antimicrobials in sewage sludge and their predicted risk to soil - Is there anything to fear?

The study assessed the occurrence of legally-monitored heavy metals and unmonitored antimicrobials in sludge from small, medium, large and very large municipal wastewater treatment plants (WWTPs), and the predicted environmental risk and risk of resistance selection associated with sludge administration to soil. The temporal variations of the studied compounds in sludge and associated risks to soil were determined by sampling over a year. Although the highest concentrations of heavy metals were noted in sludge from the largest WWTP, i.e. from 1.50 mg/kg (mean 1.61 mg/kg) for Cd to 2188 mg/kg (mean 1332 mg/kg) for Zn, the obtained values only reached a few percent of the legal limits. The same WWTP also demonstrated lower concentrations of antimicrobials compared to the smaller ones. The highest concentrations of antimicrobials, ranging from 24.04 μg/kg for trimethoprim to 900.24 μg/kg for tetracycline, were found in the small and medium WWTPs. However, due to lack of regulations at the national and EU levels, the results cannot be compared with legal limits. Principal Component Analysis (PCA), cluster and heatmap analysis separated samples according to WWTP size. Small WWTP demonstrated correlation with antimicrobials (tetracycline, trimethoprim, clindamycin, ciprofloxacin and ofloxacin), while the large and very large WWTP revealed correlations with heavy metals (Cu and Cr). The obtained environmental risk quotients confirmed that the heavy metals did not present a threat, measured either as individual risk quotients (RQenv), cumulative risk (RQcumulative) or risk of mixture of heavy metals (RQmix-metals). In the case of antimicrobials, only tetracycline demonstrated moderate RQenv, RQcumulative and RQmix-antimicrobials in the small WWTP sludge, with values of 0.1 to 1. Our findings highlight the importance of monitoring sewage sludge before soil application, especially from small WWTPs, to reduce the potential environmental impact of antimicrobials. They also confirm our previous data regarding the environmental risk associated with various toxic compounds, including emerging contaminants, in the sludge from small WWTPs.

Persistence and potential risks of tetracyclines and their transformation products in two typical different animal manure composting treatments

Abundant residues of tetracyclines in animal manures and manure-derived organic fertilizers can pose a substantial risk to environments. However, our knowledge on the residual levels and potential risk of tetracyclines and their transformation products (TPs) in manure and manure-derived organic fertilizers produced by different composting treatments is still limited. Herein, the occurrence and distribution of four veterinary tetracyclines (tetracycline, oxytetracycline, chlortetracycline, and doxycycline) and ten of their TPs were investigated in paired samples of fresh manure and manure-derived organic fertilizers. Tetracyclines and TPs were frequently detected in manure and manure-derived organic fertilizer samples in ranging from 130 to 118,137 μg·kg-1 and 54.6 to 104,891 μg·kg-1, respectively. Notably, the TPs concentrations of tetracycline and chlortetracycline were comparable to those of the parent compounds, with 4-epimers being always dominant and retained antibacterial potency. Based on paired-sampling strategy, the removal efficiency of tetracyclines and TPs in thermophilic composting was higher than that in manure storage. Toxicological data in the soil environment and the data derived from equilibrium partitioning method, indicated that tetracyclines and some TPs like 4-epitetracycline, 4-epichlortetracycline and isochlortetracycline could pose median to high ecological risk to terrestrial organisms. Total concentrations of TPs in manure-derived organic fertilizers were significantly correlated with the absolute abundance of tet(X) family genes, which provide evidence to evaluate the effects of TPs on the levels of antibiotic resistance in the environment. Among them, the 4-epitetracycline could pose ecological risk and retain antibacterial potency. Our findings emphasize the importance of monitoring and controlling the prevalence of tetracyclines and their TPs in livestock-related environments.

Gut microbiota and transcriptome response of earthworms (Metaphire guillelmi) to polymyxin B exposure

Polymyxin B (PMB) has received widespread attention for its use as a last-line therapy against multidrug-resistant bacterial infection. However, the consequences of unintended PMB exposure on organisms in the surrounding environment remain inconclusive. Therefore, this study investigated the effects of soil PMB residue on the gut microbiota and transcriptome of earthworms (Metaphire guillelmi). The results indicated that the tested doses of PMB (0.01-100 mg/kg soil) did not significantly affect the richness and Shannon's diversity index of the earthworm gut microbiota, but PMB altered its community structure and taxonomic composition. Moreover, PMB significantly affected Lysobacter, Aeromonas, and Sphingomonas in the soil microbiota, whereas Pseudomonas was significantly impacted the earthworm gut microbiota. Furthermore, active bacteria responded more significantly to PMB than the total microbial community. Bacterial genera such as Acinetobacter and Bacillus were highly correlated with differential expression of some genes, including up-regulated genes associated with folate biosynthesis, sulphur metabolism, and the IL-17 signalling pathway, and downregulated genes involved in vitamin digestion and absorption, salivary secretion, other types of O-glycan biosynthesis, and the NOD-like receptor signalling pathway. These results suggest that adaptation to PMB stress by earthworms involves changes in energy metabolism, their immune and digestive systems, as well as glycan biosynthesis. The study findings help elucidate the relationship between earthworms and their microbiota, while providing a reference for understanding the environmental risks of PMB.

Health impact assessment after Danio rerio long-term exposure to environmentally relevant concentrations of metformin and guanylurea

The antidiabetic drug metformin (MET) and its metabolite guanylurea (GUA) have been frequently and ubiquitously detected in surface water. Consequently, there has been a consistent rise in studying the toxicity of MET and GUA in fish over the past decade. Nonetheless, it is noteworthy that no study has assessed the harmful effects both compounds might trigger on fish blood and organs after chronic exposure. Taking into consideration the data above, our research strived to accomplish two primary objectives: Firstly, to assess the effect of comparable concentrations of MET and GUA (1, 40, 100 μg/L) on the liver, gills, gut, and brain of Danio rerio after six months of flow-through exposure. Secondly, to compare the outcomes to identify which compound prompts more significant oxidative stress and apoptosis in organs and blood parameter alterations. Herein, findings indicate that both compounds induced oxidative damage and increased the expression of genes associated with apoptosis (bax, bcl2, p53, and casp3). Chronic exposure to MET and GUA also generated fluctuations in glucose, creatinine, phosphorus, liver enzymes, red and white blood count, hemoglobin, and hematocrit levels. The observed biochemical changes indicate that MET and GUA are responsible for inducing hepatic damage in fish, whereas hematological alterations suggest that both compounds cause anemia. Considering GUA altered to a more considerable extent the values of all endpoints compared to the control group, it is suggested transformation product GUA is more toxic than MET. Moreover, based on the above evidence, it can be inferred that a six-month exposure to MET and GUA can impair REDOX status and generate apoptosis in fish, adversely affecting their essential organs' functioning.

Simulating fate and transport of non-steroidal anti-inflammatory drugs using Root Zone Water Quality Model 2

The fate and transport of non-steroidal anti-inflammatory drugs (NSAIDs) in soil are determined by various processes, and the complexity of the system lends itself to the use of computer simulation models to help understand it. This study demonstrated the first attempt to use empirical data from lab incubation and field studies to parameterize and test a process-based agricultural systems model, Root Zone Water Quality Model 2 (RZWQM2), to simulate the fate and transport of naproxen (NPX), ibuprofen (IBF), and ketoprofen (KTF) in field-based lysimeters amended with alkaline-treated biosolids (ATBs). The model calibrated for the soil-water balance module and contaminant transport module was used to predict water seepage through the soil profile in 2017 and 2018 within a 15% error of the field measured data, with model performance statistics such as Nash-Sutcliffe model efficiency (NSE) and R2 all greater than 0.70. The overall predicted percent recovery of initial spiked NSAIDs in both soil and water samples, after further calibration of the contaminant transport module, was within the same order of magnitude as the measured data. The model underestimated the percent recovery of initial spiked NSAIDs at the 30- to 55-cm soil depth for all treatments on day 3. The calibrated soil subsurface aerobic half-lives of NPX and IBF were found to be considerably lower than their laboratory-measured half-lives obtained from the incubation study. The overall performance of RZWQM2 in simulating the soil hydrology and behavior of NSAIDs in soil profiles receiving various rates of ATB amendments was satisfactory.

Estrogens and xenoestrogen residues in manure-based fertilizers and their potential ecological risks

Optimal manure treatment aimed at usage as agricultural soil fertilizers is a prerequisite ecological pollution control strategy. In this work, livestock manure-based fertilizers were collected from 71 animal farms across 14 provinces in China. The contamination levels and potential ecotoxicological risks of residual steroid estrogens (SEs): estrone (E1), estriol (E3), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2) and xenoestrogen (XE) bisphenol A (BPA), were investigated. The results showed that the occurrence frequencies for SEs and XE ranged from 66.67% to 100%, and the mean concentration varied considerably across the study locations. The total content of SEs and XE in Hebei province was the highest, and swine manure-based fertilizers concentrations were higher than the levels reported in other animal fertilizers. Compared with farm level manure, manure-based fertilizers are processed by composting, and the micropollutants quantities are significantly reduced (mean: 87.65 - 534.02 μg/kg). The total estradiol equivalent quantity (EEQ) that might migrate to the soil was estimated to be 1.23 μg/kg. Based on the estimated application rate of manure, 38% of the fertilizers risk quotients exceeded 0.1, indicating medium to high risks pressure on terrestrial organisms. Nonetheless, the estrogenic risk was lower in manure-based fertilizers than in manure. This study highlights the significance of proper treatment of livestock manure and designing an optimal manure fertilization strategy to mitigate the risks posed by SEs and XEs to the agroecosystems.

Risk control of antibiotics, antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) during sewage sludge treatment and disposal: A review

Sewage sludge is an important reservoir of antibiotics, antibiotic resistance genes (ARGs), and antibiotic resistant bacteria (ARB) in wastewater treatment plants (WWTPs), and the reclamation of sewage sludge potentially threats human health and environmental safety. Sludge treatment and disposal are expected to control these risks, and this review summarizes the fate and controlling efficiency of antibiotics, ARGs, and ARB in sludge involved in different processes, i.e., disintegration, anaerobic digestion, aerobic composting, drying, pyrolysis, constructed wetland, and land application. Additionally, the analysis and characterization methods of antibiotics, ARGs, and ARB in complicate sludge are reviewed, and the quantitative risk assessment approaches involved in land application are comprehensively discussed. This review benefits process optimization of sludge treatment and disposal, with regard to environmental risks control of antibiotics, ARGs, and ARB in sludge. Furthermore, current research limitations and gaps, e.g., the antibiotic resistance risk assessment in sludge-amended soil, are proposed to advance the future studies.

Stressors of emerging concern in deep-sea environments: microplastics, pharmaceuticals, personal care products and deep-sea mining

Although most deep-sea areas are remote in comparison to coastal zones, a growing body of literature indicates that many sensitive ecosystems could be under increased stress from anthropogenic sources. Among the multiple potential stressors, microplastics (MPs), pharmaceuticals and personal care products (PPCPs/PCPs) and the imminent start of commercial deep-sea mining have received increased attention. Here we review recent literature on these emerging stressors in deep-sea environments and discuss cumulative effects with climate change associated variables. Importantly, MPs and PPCPs have been detected in deep-sea waters, organisms and sediments, in some locations in comparable levels to coastal areas. The Atlantic Ocean and the Mediterranean Sea are the most studied areas and where higher levels of MPs and PPCPs have been detected. The paucity of data for most other deep-sea ecosystems indicates that many more locations are likely to be contaminated by these emerging stressors, but the absence of studies hampers a better assessment of the potential risk. The main knowledge gaps in the field are identified and discussed, and future research priorities are highlighted to improve hazard and risk assessment.

Exploring the correlations between epi indicators of COVID-19 and the concentration of pharmaceutical compounds in wastewater treatment plants in Northern Portugal

The COVID-19 pandemic caused by the SARS-CoV-2 virus led to changes in the lifestyle and human behaviour, which resulted in different consumption patterns of some classes of pharmaceuticals including curative, symptom-relieving, and psychotropic drugs. The trends in the consumption of these compounds are related to their concentrations in wastewater systems, since incompletely metabolised drugs (or their metabolites back transformed into the parental form) may be detected and quantified by analytical methods. Pharmaceuticals are highly recalcitrant compounds and conventional activated sludge processes implemented in wastewater treatment plants (WWTP) are ineffective at degrading these substances. As a results, these compounds end up in waterways or accumulate in the sludge, being a serious concern given their potential effects on ecosystems and public health. Therefore, it is crucial to evaluate the presence of pharmaceuticals in water and sludge to assist in the search for more effective processes. In this work, eight pharmaceuticals from five therapeutic classes were analysed in wastewater and sludge samples collected in two WWTP located in the Northern Portugal, during the third COVID-19 epidemic wave in Portugal. The two WWTP demonstrated a similar pattern with respect to the concentration levels in that period. However, the drugs loads reaching each WWTP were dissimilar when normalising the concentrations to the inlet flow rate. Acetaminophen (ACET) was the compound detected at highest concentrations in aqueous samples of both WWTP (98. 516 μg L ^- 1 in WWTP2 and 123. 506 μg L ^- 1in WWTP1), indicating that this drug is extensively used without the need of a prescription, known of general public knowledge as an antipyretic and analgesic agent to treat pain and fever. The concentrations determined in the sludge samples were below 1.65 µg g ^- 1 in both WWTP, the highest value being found for azithromycin (AZT). This result may be justified by the physico-chemical characteristics of the compound that favour its adsorption to the sludge surface through ionic interactions. It was not possible to establish a clear relationship between the incidence of COVID-19 cases in the sewer catchment and the concentration of drugs detected in the same period. However, looking at the data obtained, the high incidence of COVID-19 in January 2021 is in line with the high concentration of drugs detected in the aqueous and sludge samples but prediction of drug load from viral load data was unfeasible.

Fate and toxicity of triclosan in tidal flow constructed wetlands amended with cow dung biochar

Triclosan (TC) is one of the threats to the environment due to its bioaccumulative nature, persistency, combined toxicity in aquatic biota, and endocrine-disrupting nature. This study revealed the removal of TC via three distinct setups of vertical flow constructed wetlands (VFCW: B-VFCW (with biochar); PB-VFCW (with plant Colocasia and biochar); C-VFCW (without biochar but with plant)) operated with normal flow and tidal-flow (flooding/drying cycles of 72 h/24 h: B-TFCW; PB-TFCW; C-TFCW) mode for 216 h of the operation cycle. The effluent was analyzed for changes in TC load and wastewater parameters (COD, NO₃-N, NH₄⁺-N, and DO). TC reduction efficiency (%) was found to be higher in PB-TFCW (98.41) followed by, C-TFCW (82.41), B-TFCW (77.51), PB-VFCW (71.83), C-VFCW (64.25), and B-VFCW (52.19) (p < 0.001). Reduction efficiency for COD (29-75 - 53.10%), and NH₄⁺-N (86.5-97.9%) was better in TFCWs than that of setups with a normal mode of operation. TFCWs showed higher DO (3.87-4.89 mg L^-1) during the operation period than that of VFCWs. The toxic impact of TC in plant stand was also assessed and results suggested low phototoxic and oxidative enzyme activities (catalase, CAT; superoxide dismutase, SOD; hydrogen peroxide, H₂O₂; malondialdehyde, MDA) in TFCWs. In summary, biochar addition and tidal flow operation played a significant role in oxidative- and microbial-mediated removals of TC in wastewater. This study provides an alternative strategy for the efficient removals of TC in constructed wetland systems and new insights into the toxic impact of pharmaceuticals on wetland plants.

Predictive modeling of pharmaceutical product removal by a managed aquifer recharge system: Comparison and optimization of models using ensemble learners

Pharmaceutical products (PPs) are emerging water pollutants with adverse environmental and health-related impacts, owing to their toxic, persistent, and undetectable microscopic nature. Globally, increasing scientific knowledge and advanced technologies have allowed researchers to study PP-associated problems and their removal for water reuse. Experimental modeling methods require laborious, lengthy, expensive, and environmentally hazardous lab-work to optimize the process. On the other hand, predictive machine learning (ML) models can trace the complex input-output relationship of a process using available datasets. In this study, ensemble ML techniques, including decision tree (DT), random forest (RF), and Xtreme gradient boost (XGB), were used to explore PP (diclofenac, iopromide, propranolol, and trimethoprim) removal by a managed aquifer recharge (MAR) system. The model input parameters included characteristics of reclaimed water and soil used in the columns, pH, dissolved organic carbon, operating time, nitrogen dioxide, sulfate, nitrate, electrical conductivity, manganese, and iron. The selected PP removal was the model output. Datasets were collected through a one-year experimental study of continuous MAR system operation to predict the removal of PPs. DT, RF, and XGB models were then developed for one of the selected compounds and tested for the others to check the reliability of the ML model results. The developed models were assessed using statistical performance matrices. The experimental results showed >80% removal of propranolol and trimethoprim; however, removal of diclofenac and iopromide was only ≈50% by the MAR system. The proposed DT and RF models presented higher coefficients of determination (R² ≥ 0.92) for diclofenac, propranolol, and trimethoprim than for iopromide (R² ≤ 0.63). In contrast, the XGB model showed better results for diclofenac, iopromide, propranolol, and trimethoprim, with R² values of 0.92, 0.72, 0.96, and 0.97, respectively. Therefore, XGB could be the best predictive model to provide insight into the adaptation of ML models to predict PP removal by the MAR system, thereby minimizing experimental work.

Novel nonylphenol-degrading bacterial strains isolated from sewage sludge: Application in bioremediation of sludge

Nonylphenol (NP) is an anthropogenic pollutant frequently found in sewage sludge due to the insufficient degrading effectiveness of conventional WWTPs and has attracted attention as an endocrine disruptor. The aim of this study was to isolate specific NP-degrading bacteria from sewage sludge to be used in the degradation of this contaminant through bioaugmentation processes in aqueous solution and sewage sludge. Up to eight different bacterial strains were isolated, six of them not previously described as NP degraders. Bacillus safensis CN12 presented the best NP degradation in solution, and glucose used as an external carbon source increased its effect, reaching DT₅₀ degradation values (time to decline to half the initial concentration of the pollutant) of only 0.9 days and a complete degradation in <7 days. Four NP metabolites were identified throughout the biodegradation process, showing higher toxicity than the parent contaminant. In sewage sludge suspensions, the endogenous microbiota was capable of partially degrading NP, but a part remained adsorbed as bound residue. Bioaugmentation was used for the first time to remove NP from sewage sludge to obtain more environmentally friendly biosolids. However, B. safensis CN12 was not able to degrade NP due to its high adsorption on sludge, but the use of a cyclodextrin (HPBCD) as availability enhancer allowed us to extract NP and degrade it in solution. The addition of glucose as an external carbon source gave the best results since the metabolism of the sludge microbiota was activated, and HPBCD was able to remove NP from sewage sludge to the solution to be degraded by B. safensis CN12. These results indicate that B. safensis CN12 can be used to degrade NP in water and sewage sludge, but the method must be improved using consortia of B. safensis CN12 with other bacterial strains able to degrade the toxic metabolites produced.

Removal of toxic metals from sewage sludge by EDTA in a closed-loop washing process

Sewage sludge (SS) is a potential resource for P and other nutrients, but often contaminated with metals. SS containing Pb-102, Zn-968, Cu-267, Cr-101, Mn-222, and Fe-8374 mg kg^-1 was washed in a batch process for 1 h with a recycled washing solution containing 50 mmol L^-1 of recycled EDTA and 50 mmol L^-1 H₂SO₄, solid/liquid ratio 1/7 (w/V). After solid/liquid separation, the washed SS was further rinsed 3-times with cleansed recycled solutions. EDTA and process solutions were recycled/cleansed in a pH gradient of 12.5-2.0 imposed by addition of CaO and H₂SO₄ (the ReSoil® method). EDTA, recycled as ineffective Ca-EDTA, was activated by capturing Ca with H₂SO₄. The process was closed-looped, no wastewater was generated, solid waste was centrifuged away. 10 consecutive SS washing batches preserved the quality of the process solutions. Metals were mainly removed from the SS organic fraction, the average removal was Pb-35, Zn-59, Cu-60, Cr-19, Mn-25, and Fe-1%. Washing reduced the leachability of Cu and Cr from SS by 13.4 and 3.5 times, but increased the leachability of Pb, Zn, Mn, and Fe by 2.5, 3.8, 1.9, and 1.6 times, respectively. Metal concentrations in the leachates were below the limits stipulated as hazardous. The content of accessible P and K in washed SS decreased by 24 and 45%, and the total N decreased by 10%. Overall, the results prove the feasibility of the novel SS washing process.

Triclosan and triclocarban as potential risk factors of colitis and colon cancer: Roles of gut microbiota involved

In recent decades there has been a dramatic increase in the incidence and prevalence of inflammatory bowel disease (IBD), a chronic inflammatory disease of the intestinal tissues and a major risk factor of developing colon cancer. While accumulating evidence supports that the rapid increase of IBD is mainly caused by exposure to environmental risk factors, the identities of the risk factors, as well as the mechanisms connecting environmental exposure with IBD, remain largely unknown. Triclosan (TCS) and triclocarban (TCC) are high-volume chemicals that are used as antimicrobial ingredients in consumer and industrial products. They are ubiquitous contaminants in the environment and are frequently detected in human populations. Recent studies showed that exposure to TCS/TCC, at human exposure-relevant doses, increases the severity of colitis and exacerbates colon tumorigenesis in mice, suggesting that they could be risk factors of IBD and associated diseases. The gut toxicities of these compounds require the presence of gut microbiota, since they fail to induce colonic inflammation in mice lacking the microbiota. Regarding the functional roles of the microbiota involved, gut commensal microbes and specific microbial β-glucuronidase (GUS) enzymes mediate colonic metabolism of TCS, leading to metabolic reactivation of TCS in the colon and contributing to its subsequent gut toxicity. Overall, these results support that these commonly used compounds could be environmental risk factors of IBD and associated diseases through gut microbiota-dependent mechanisms.

Metformin as an emerging concern in wastewater: Occurrence, analysis and treatment methods

Metformin is a wonder drug used as an anti-hypoglycemic medication; it is also used as a cancer suppression medicament. Metformin is a first line of drug choice used by doctors for patients with type 2 diabetes. It is used worldwide where the drug's application varies from an anti-hypoglycemic medication to cancer oppression and as a weight loss treatment drug. Due to its wide range of usage, metformin and its byproducts are found in waste water and receiving aquatic environment. This leads to the accumulation of metformin in living beings and the environment where excess concentration levels can lead to ailments such as lactic acidosis or vitamin B12 deficiency. This drug could become of future water treatment concerns with its tons of production per year and vast usage. As a result of continuous occurrence of metformin has demanded the need of implementing and adopting different strategies to save the aquatic systems and the exposure to metformin. This review discuss the various methods for the elimination of metformin from wastewater. Along with that, the properties, occurrence, and health and environmental impacts of metformin are addressed. The different analytical methods for the detection of metformin are also explained. The main findings are discussed with respect to the management of metformin as an emerging contaminants and the major recommendations are discussed to understand the major research gaps.

Impact of fertilization with pig or calf slurry on antibiotic residues and resistance genes in the soil

Antibiotic residues and antibiotic resistance genes can enter the environment via fertilization with calf and pig manure. In a longitudinal study, nine antibiotic resistance genes (tet(B), tet(L), tet(M), tet(O), tet(Q), tet(W), erm(B), erm(F) and sul2) and 56 antibiotic residues were investigated in 288 soil samples and 8 corresponding slurry samples from 6 pig farms and 2 veal farms using qPCR and LC-MS/MS, respectively. A significant increase in gene copy number of tet(M), erm(B), erm(F) and sul2 was observed in all the soil layers between sampling times prior to (T1) and 2-3 weeks after fertilization (T3). Tet(B), tet(Q) and tet(L) were least abundant in the soil among the genes tested. From 7 classes of antibiotics, 20 residues were detected in soil and slurry using an optimized and validated extraction method. Flumequine was detected in all soil samples in concentrations below 100 μg/kg despite being detected in only half of the corresponding slurry samples. Doxycycline, oxytetracycline, lincomycin and sulfadiazine were also frequently detected in concentrations ranging from 0.1 μg/kg to 500 μg/kg and from 2 μg/kg and 9480 μg/kg in soil and slurry, respectively. Furthermore a positive association between the presence of antibiotic residues (total antibiotic load) and antibiotic resistance genes in soil was found. One possible explanation for this is a simultaneous introduction of antibiotic residues and resistance genes upon application of animal slurry.

Occurrence and risk assessment of trace organic contaminants and metals in anaerobically co-digested sludge

Anaerobic co-digestion of sludge increases biogas production and maintains anaerobic digestion stability. However, it is unclear whether the addition of co-substrates may increase the concentration of trace organic contaminants (TrOCs) and metals, limiting potential resource recovery opportunities when applied to agricultural land. This study explored the occurrence of 20 TrOCs and 18 metals in wastewater sludge anaerobically co-digested with beverage rejects (cola, beer and juice) and food wastes. TrOCs results showed that cola reject caused an accumulation of caffeine in final digestate. Bisphenol A also significantly increased in food waste co-digestion when compared with the mono-digestion (control). No significant difference in TrOCs was observed in the juice reject co-digestion. Analysis of the metal composition revealed a significant increase in Cr and Al in juice reject co-digested sludge. While restaurant food waste increased concentrations of K and Ca, both of which may be beneficial when applied to land. All metals in this study were below the maximum permissible concentrations specified for agricultural land use in Australia. Environmental risk assessment of sludge when used as soil fertiliser, showed that caffeine, diuron, triclocarban, triclosan, Cu and Zn exhibited high risks, with the largest risk quotient (RQ) posed by caffeine. Estrone and naproxen implied medium risks, and ibuprofen implied a high risk except for the co-digestion using cola reject (RQ = 0.9, medium risk). The results emphasise the importance for wastewater utility operators to understand the impact of co-substrate selection on the quality of sludge to minimise environmental risk from the use of biosolids on agricultural land.

Influence of selected antibiotics on respirometric activity of activated sludge

The main topic of this study is to determine the effect of selected antibiotics on the respirometric activity of sewage sludge microorganisms. Within the practical part of the work, several respirometric measurements were performed with activated sludge from a wastewater treatment plant, while the influence of three selected antibiotics — sulfamethoxazole, sulfapyridine, and ciprofloxacin, on sludge activity was monitored. The aim of the work was to point out the inhibitory effect of all monitored compounds on sludge activity and to quantify the inhibitory effect. For sulfamethoxazole (in the concentration range of 0.142—1.42 mg·L−1), the determined inhibition was in the range of 9.67—27.7 %, depending on the concentration of the test substance and the type of respirometric measurements. For sulfapyridine, inhibition values ranged from 1.13 % to 31.9 % for the concentration range from 0.134 to 1.34 mg·L−1. Ciprofloxacin inhibited the activity of activated sludge microorganisms in the range of 4.55 % to 28.8 % (at CPX concentrations from 0.104 to 1.04 mg·L−1).

Biomarker responses and metabolism in Lumbricus terrestris exposed to drugs of environmental concern, an in vivo and in vitro approach

The earthworm Lumbricus terrestris is an anecic species living in natural soils but it is also a sentinel in pollution monitoring. Specimens of L.terrestris were exposed for 48 h though the filter paper contact test at 1 mg/mL of the chemicals: Lamotrigine (LMG), Cocaine (COC), Fipronil (FIP) and the pesticide bis-4-nitrophenyl phosphate (BNPP). After that period, the activities of Acetylcholinesterase, Glutathione S-transferase, Carboxylesterase (CE) using different substrates, and lipid peroxidation levels were evaluated in the exposed whole tissue earthworms. The results revealed differences only in CE activity, with 4-nitrophenyl butyrate (4NPB) and 1-naphthyl butyrate (1NB) the most responsive substrates to COC. The kinetic parameters of CE were characterized, for the first time, in whole tissue of this species. The chemical analysis by LC-MS/MS, confirmed the exposure to the parent compounds, identified metabolites and evidenced biotransformation pathways in earthworms. Metabolic reactions included oxidation (LMG and FIP), hydrolysis (COC and FIP) as well as glycosylation (LMG, COC and FIP). A hitherto unknown metabolite of LMG due to the conjugation with phenylalanine glutamine was formed. The in vivo results on CE activity with the specific inhibitor, BNPP, were confirmed in vitro. Moreover, in the in vitro approach, the inclusion of other contaminants of environmental concern supports the potential of CE as biomarker. This study identifies the main metabolites formed by earthworms for further in vivo exposures under more realistic conditions and the potential use of CE measures as biomarker of emerging contaminants.

Veterinary antibiotics and estrogen hormones in manures from concentrated animal feedlots and their potential ecological risks

The spread of pharmaceutically active chemicals (PACs), such as antibiotics and estrogenic hormones from animal manures can pose threats to the ecologic environment. In this work, animal manure samples were collected from 71 concentrated animal feedlots in Northern China and investigated for 24 antibiotics and 4 estrogenic hormones. Results showed that these micropollutants were ubiquitous in manures with the concentration ranges of undetectable (ND)-543,445 μg/kg (mean: 44,568 μg/kg) for antibiotics and ND-249.8 μg/kg (mean: 24.78 μg/kg) for estrogens. There was a significant variation in the amounts of PACs in different animal manures. The amounts of antibiotics in manures had following order: swine (83,177 μg/kg) >chicken (52,932 μg/kg) >beef (37,120 μg/kg) >dairy (305 μg/kg), while the estrogens in dairy (mean: 39.27 μg/kg) and chicken manures (mean: 40.08 μg/kg) were higher than those in beef (2.7 μg/kg) and swine manures (1.8 μg/kg). Based on the estimated farmland application rate of manure, antibiotics and estrogens may cause high ecological risks to terrestrial organisms according to the risk quotient evaluation. Estrogens could pose a relatively higher risk than antibiotics. The toxicological effects of antibiotics and estrogens to the terrestrial environment should receive more intensive study.

Presence of Antibiotic Residues and Antibiotic Resistant Bacteria in Cattle Manure Intended for Fertilization of Agricultural Fields: A One Health Perspective

Antibiotic resistant bacteria and antibiotic residues can enter the environment when using animal manure as fertilizer. Twenty-five mixed beef cattle farmyard manure samples and 9 mixed fattening calf slurry samples from different farms across Belgium were investigated for the presence of 69 antibiotic residues, antibiotic resistant Escherichia coli and Salmonella spp. Doxycycline, oxytetracycline, ciprofloxacin, enrofloxacin, flumequine and lincomycin were detected in all fattening calf slurry samples with mean concentrations of 2776, 4078, 48, 31, 536 and 36 µg/kg manure, respectively. Sulfadiazine was detected at a mean concentration of 10,895 µg/kg. Further, antibiotic residues were found in only 4 of the 25 beef cattle farmyard manure samples. Oxytetracycline was detected twice below 500 µg/kg. Paromomycin, ciprofloxacin and enrofloxacin were detected in a concentration below 100 µg/kg. Of E. coli isolates, 88% and 23% from fattening calf slurry and beef cattle farmyard manure, respectively, were resistant to at least one of the antibiotics tested. Multi-drug resistance was observed at a maximum of 10 and 7 antibiotics, respectively. The occurrence of antibiotic resistant E. coli and antibiotic residues is shown to be higher in fattening calf slurry than in beef cattle farmyard manure used for agricultural field fertilization.

Biodegradation kinetics of individual and mixture non-steroidal anti-inflammatory drugs in an agricultural soil receiving alkaline treated biosolids

Land application of biosolids is one potential source of pharmaceuticals and personal care products (PPCPs) into agricultural soils. Degradation is an important natural attenuation pathway that affects the fate and transport of PPCPs in the soil system and biosolids application could alter the process. The present study assessed the effect of individual and mixture compound environments on the biodegradation rate and half-life of three non-steroidal anti-inflammatory drugs (NSAIDs), naproxen (NPX), ibuprofen (IBF), and ketoprofen (KTF), in a loamy sand textured agricultural soil receiving an alkaline treated biosolid (ATB) amendment. A prolonged half-life of the target NSAIDs was determined for sterile soils and shorter half-lives in unsterile soils, indicating the loss of target compounds in all treatments was mainly attributed to biodegradation and followed first-order kinetics. IBF and NPX showed low to moderate persistence in soil and ATB amended soil, with half-lives ranging from 4.9 to 14.8 days, while KTF appeared to be highly persistent with an average half-life of 33 days. The order in which the target NSAIDs disappeared in both soil and ATB amended soil was: IBF > NPX > KTF, for both individual and mixture compound treatments. Soils that received the ATB amendment demonstrated inhibited degradation of NPX in all treatments, as well as IBF and KTF in individual compound treatment over the 14-day incubation study. We also observed an inhibition effect from the ATB amendment in sterile soil treatments. In mixture compound treatments, IBF degradation was inhibited in both soil and ATB amended soil. The degradation rate of KTF in mixture compound environment in soil was lower, while the opposite effects were observed in ATB amended soils. For NPX, the degradation was enhanced in mixture compound environment in ATB amended soil, while the same degradation rate of NPX was calculated in soil.

Optimized Photo-Fenton degradation of psychoactive pharmaceuticals alprazolam and diazepam using a chemometric approach-Structure and toxicity of transformation products

The objectives of the present study were: a) to evaluate the photocatalytic degradation of two benzodiazepine pharmaceuticals, alprazolam and diazepam, using Photo-Fenton, b) to optimize the experimental parameters through a central composite experimental design, c) to assess their mineralization and toxicity variations and d) to identify the transformation products during the process and to propose transformation pathways. Response Surface Methodology proved to be a useful tool for the optimization of the degradation process as the statistical coefficients (R² = 0.967 for alprazolam and R² = 0.929 for diazepam) showed satisfactory values confirming the adequate correlation between the predicted models and experimental values. Two sets of experimental conditions were proposed taking into consideration criteria related to the reaction rate and the minimum use of iron. Toxicity of the system varied with time after the treatment, indicating the gradual production of transformation products which differ in their toxic potential. Fifteen and twenty-three photocatalytic degradation products were identified for ALP and DZP respectively using LC-(ESI)MS/MS. In the case of ALP, the main degradation reactions included, phenyl-group removal and the opening of the 7-membered ring, while for DZP, degradation occurred through hydroxylation, formation of benzophenone and the opening of the 7-membered cyclic group.

A multi-residue analytical method for extraction and analysis of pharmaceuticals and other selected emerging contaminants in sewage sludge

Sewage sludge is a by-product of wastewater treatment processes, and may be employed in agriculture as a fertilizer or in forestry for land reclamation. It is an important source of nutrients but its reuse can arouse concern on account of the wide range of contaminants that are retained and may persist during treatments. Information on the emerging contaminants (ECs) in sewage sludge in Italy is limited. The present study developed and applied a reliable analytical method for the analysis of 44 ECs in sewage sludge. ECs were extracted by accelerated solvent extraction followed by a clean-up step on solid-phase cartridges. High performance liquid chromatography coupled to mass spectrometry was used for analysis. The ECs, selected on the basis of their use and documented presence in the environment, were 42 pharmaceuticals belonging to 12 therapeutic categories and 2 perfluorinated substances. The method performance was good, with recoveries higher than 70%, good repeatability (<20%) and sensitivity in the low ng g^-1 range, allowing measurement of the analytes selected. The method was applied for analysis of sludge from 12 wastewater treatment plants in Italy. The most abundant compounds were antibiotics, anti-inflammatories and antihypertensives and ranged up to 5 μg g^-1 (ciprofloxacin). Seasonal differences were found for some antibiotics and anti-inflammatory drugs as well as some differences - in terms of concentration - with other European countries. This is the first Italian study to investigate the presence of a large number of ECs in sewage sludge and the results may be useful to drive future regulatory actions.

Large scale micropollutants and lipids screening in the sludge layers and the ecosystem of a vertical flow constructed wetland

Wastewater is one of the major sources of micropollutant release into the environment. In order to reduce the impact of wastewater, wastewater treatment plants (WWTP) have been set up, in the instance of vertical flow constructed wetlands (VFCWs). Besides, micropollutants could represent a vast diversity of compounds and compound's choice could bias studies focused on their fate. To overcome this bias, non-targeted screening approaches can be performed. Therefore, the diffusion of micropollutants from raw wastewater in the VFCW compartments (wastewater, plants and sludge) as well as their fate have been investigated using this non-target approach with liquid chromatography (LC) coupled to high resolution mass spectrometry (HRMS) and gas chromatography (GC) coupled to mass spectrometry. To help the operators in their sludge management, this study will be focused on the following question: Is there a specific distribution of micropollutants according to sludge layers? To eliminate the background contamination found both inside the CW and in the surrounding environment, a control coring was performed in bank. A specific distribution could be observed in the top (191 compounds) and bottom layers (38 compounds). However, a distribution over the whole depth for xenobiotics was observed. Micropollutants classes and the main microbial productivity were preferably found in the top layer. The micropollutants fate could however not be restricted to the sludge compartment. Therefore, the specific micropollutants distribution was analyzed in the outputs of the system in their interactions with wastewater (effluent, sludge, and reed rhizomes) to understand their fate. In our study, the results highlighted a consistent part of compounds found in at least two or three of these compartments, with a similar trend in each compartment. These results underline the interactions between the compartments and the global issues of micropollutants distribution as well as its wide spreading in the whole CW ecosystem.

Pharmaceuticals and personal care products in a Brazilian wetland of international importance: Occurrence and environmental risk assessment

Despite the fact that the occurrence of emerging contaminants in the environment has become frequent in recent decades, the seasonal dynamics of contaminants in different environmental compartments are little studied in protected areas influenced by effluent discharges. In this study, the seasonal and spatial occurrence of 33 pharmaceuticals and personal care products (PPCPs) was investigated in surface waters and sediments from Anil and Bacanga rivers (northeast of Brazil). The studied area is located within a Wetland of International Importance by Ramsar Convention (Amazon Estuary and its Mangroves). Sample preparation was carried out using solid-phase extraction and QuEChERS, for water and sediment samples, respectively and all determinations were performed by liquid chromatography tandem mass spectrometry. Eleven PPCPs were detected in water samples and 14 in sediments. In aqueous samples, caffeine was the most occurring compound reaching 13,798 ng L^-1. In addition, high levels of acetaminophen, ibuprofen, sulfamethoxazole, carbamazepine and diclofenac were also observed. In the sediment samples, triclocarban, benzophenone-3, ketoconazole and methylparaben were also detected. The spatial and temporal distribution of the assessed molecules indicates urbanization and anthropic activities as relevant sources of PPCPs in the region. Moreover, the levels of acetaminophen, caffeine, diclofenac, ibuprofen, benzophenone-3, triclosan and triclocarban measured within the Ramsar site pose a high risk to aquatic and terrestrial organisms. These findings indicate potential threats to the allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect this unique and vulnerable area.

Chemical reagent-assisted phytoextraction of heavy metals by Bryophyllum laetivirens from garden soil made of sludge

Making municipal sludge into garden soil is a challenging issue in land using due to the high content of heavy metals, however phytoremediation can reduce the heavy metal pollution in the soil. Three artificial regulators were used in combination to improve phytoremediation of heavy metals by Bryophyllum laetivirens from municipal sludge made garden (MSMG) soil. Results showed that B. laetivirens grew well in MSMG soil and bioaccumulated Cu, Pb, Zn, Cd, and Ni by 2.16-11.0 times higher than those grew in local common garden soil. The application of ethylenediaminetetraacetic acid (EDTA), indole-3-acetic acid (IAA) and microbial liquid (BL) promoted the bioaccumulation of heavy metals of plants in MSMG soil, with 2.1-6.8 times than the control group. The optimum dose for the phytoremediation of B. laetivirens was the combining treatment of 3 mmol kg^-1 EDTA, 10^-10 M IAA, and 5 ml kg^-1 BL, which has been successfully applied in MSMG soil. EDTA treatment is more direct and effective in facilitating HM uptake of root, while the other two treatments play important roles in promoting the transport of HMs in plants.

Effects of sewage sludge supplementation on heavy metal accumulation and the expression of ABC transporters in Sinapis alba L. during assisted phytoremediation of contaminated sites

ATP binding cassette (ABC) transporters, types C, G, and B were monitored via qPCR in order to investigate the influence of heavy metal (HM) contamination of post-industrial and post-agricultural soils and the effects of its supplementation with sewage sludge, on Sinapis alba plants. Five house-keeping genes were selected and validated to ensure the best reference points. The relative expression of ABC types C and G genes was profoundly affected by experimental conditions and included their upregulation after plants exposure to heavy metals and downregulation after supplementation with sewage sludge. However, ABC type C was more responsive then type G. The experimental conditions altered the expression of ABC type C gene faster than ABC type G and thus, the expression of ABC type C can therefore potentially be used as a bioindicator during assisted phytoremediation of degraded sites. In clean soil, supplementation with sewage sludge with a slight content of heavy metals still caused an upregulation in the expression of ABC types C and G, which showed that proper toxicity assessments are necessary to ensure safe application of sewage sludge into soils. Results showed that the analysed genes take a significant part in plants metal detoxification and that their expression is regulated at transcriptional level after exposure to soil contaminated with heavy metals by both, industrial activities and by sewage sludge supplementation. Thus, their expression can potentially be used as an early-warning biomarker when soil supplementation with sewage sludge is incorporated into the soil-management process.

Occurrence, fate and environmental risk of anionic surfactants, bisphenol A, perfluorinated compounds and personal care products in sludge stabilization treatments

In this work, twenty-three endocrine disrupting compounds have been monitored in sludge from different stages of four sludge stabilization treatments (anaerobic digestion, aerobic digestion, composting and anaerobic stabilization ponds). Their occurrence and fate in sludge stabilization plants and their potential environmental risk in treated sludge and in treated sludge-amended soils have been evaluated. Monitored compounds were six perfluoroalkyl compounds (PFC), four anionic surfactants (sodium alkylsulfates), a plasticiser (bisphenol A (BPA)), four preservatives (parabens), six UV-filters (benzophenones) and two biocides (triclosan and triclocarban). Only two of the UV-filters were not detected in any of the 141 analysed samples. Anionic surfactants (mean concentrations up to 1673 ng/g dry matter (dm) for the sum of surfactants) were the compounds at the highest concentration levels followed by biocides (up to 512 ng/g dm) and UV-filters (up to 662 ng/g dm). The concentrations of anionic surfactants, preservatives and UV-filters decreased 78, 25 and 80%, respectively, after anaerobic digestion. The concentration of perfluorinated carboxylic acids only decreased after composting (80% reduction) whereas biocides and BPA were not affected by any of the studied treatments. Environmental risks (risk quotients > 1) were obtained for all compounds, except for triclocarban and sodium octadecylsulfate, in treated sludge. In treated sludge-amended soils, risk quotients were lower than 1 for all compounds except for triclosan.

A review of the occurrence of selected micropollutants and microorganisms in different raw and treated manure - Environmental risk due to antibiotics after application to soil

This study consists of a review based on 104 papers published between 1980 and 2019, which dealt with the occurrence of pharmaceuticals, hormones and a selection of microorganisms in raw and treated manure from different types of animal farms. The selected pharmaceuticals and hormones are those regularly administered to livestock for treating and preventing diseases. Worldwide, manure is commonly spread on soil as a fertilizer due to its nutrient content. However, this practice also represents a potential pathway for micropollutant release into the environment. In this context, this study evaluates the predicted concentrations of some antibiotics in soil after the application of swine slurry on soil and compares them with corresponding measured concentrations found in the literature. Enrofloxacin, oxytetracycline and chlortetracycline were the antibiotics with the highest concentrations that were found in raw and treated manure and that showed a high risk together with sulfamethazine. Future research should focus on monitoring other pathogens, parent compounds and their main metabolites in raw and treated manure, studying the spread and development of antibiotic resistance genes in the environment due to residues of antibiotics in manure applied to soil, and evaluating predicted no effect concentrations of pharmaceuticals and hormones commonly administered to livestock with regard to terrestrial organisms.

Occurrence, toxic effects and removal of metformin in the aquatic environments in the world: Recent trends and perspectives

Metformin (MET) is the most common drug used to treat type 2 diabetes, but also it is used as an anticancer agent and as a treatment for polycystic ovary syndrome. This drug is not metabolized in the human body, and may enter into the environment through different pathways. In wastewater treatments plants (WWTPs), this contaminant is mainly transformed to guanylurea (GUA). However, three further transformation products (TPs): (a) 2,4- diamino-1,3,5-triazine, 4-DAT; (b) 2-amino-4-methylamino-1,3,5-triazine, 2,4-AMT; and (c) methylbiguanide, MBG; have also been associated with its metabolism. MET, GUA and MBG have been found in WWTPs influents, effluents and surface waters. Furthermore, MET and GUA bioaccumulate in edible plants species, fish and mussels potentially contaminating the human food web. MET is also a potential endocrine disruptor in fish. Phytoremediation, adsorption and biodegradation have shown a high removal efficiency of MET, in laboratory. Nonetheless, these removal methods had less efficiency when tried in WWTPs. Therefore, MET and its TPs are a threat to the human being as well as to our environment. This review comprehensively discuss the (1) pathways of MET to the environment and its life-cycle, (2) occurrence of MET and its transformation products (3) removal, (4) toxic effects and (5) future trends and perspectives of possible methods of elimination in water in order to provide potential options for managing these contaminants.

Thermal hydrolysis of sewage sludge partially removes organic micropollutants but does not enhance their anaerobic biotransformation

Pretreatment technologies prior to anaerobic digestion (AD) have been developed with the aim of enhancing biogas productivity and reducing the presence of pathogens in digested sludge. Among them, thermal hydrolysis (TH) appears as the most promising one. In wastewater treatment plants (WWTPs) sludge is the end point of many organic micropollutants (OMPs), which was proved to lead to important environmental and human risks since sludge is commonly used in agriculture. The objective of this work is to determine the fate OMPs in TH and subsequent AD. Sewage sludge was pretreated in a TH pilot plant at 170 °C for 20 min. Afterwards, two anaerobic digesters with a working volume of 14 L fed with fresh and pretreated sludge were operated in parallel in mesophilic conditions. TH proved to be an effective technology to partially or totally remove the dissolved fraction of OMPs as well as the fraction sorbed into those suspended solids that are solubilised after this pretreatment. However, it did not affect the OMPs sorbed concentration into solids that are not solubilised. Globally, the OMPs removal efficiency during TH appears to be linked to the solids solubilisation during this process. Afterwards, the OMPs biotransformation efficiency in AD of fresh and pretreated sludge was determined. Noticeable differences between the microbiome of both reactors was determined, but the anaerobic biotransformation was not substantially different for most of the OMPs. However, it affected musk fragrances, which presented considerably lower biotransformation efficiency in the reactor fed with pretreated sludge. Therefore, TH was proved effective in partially removing OMPs but not in enhancing their bioavailability and subsequent anaerobic biotransformation.

Assessment of bisphenol-A in the urban water cycle

The plasticizer bisphenol-A (BPA) is common to municipal wastewaters and can exert toxicity to exposed organisms in the environment. Here BPA concentration at 5 sewage treatment works (STW) and distribution throughout a river catchment in South West UK were investigated. Sampling sites included influent and effluent wastewater (n = 5), river water (n = 7) and digested sludge (n = 2) which were monitored for 7 consecutive days. Findings revealed average BPA loads in influent wastewater at two STWs were 10-37 times greater than the other wastewaters monitored. Concentrations up to ~100 μg L^-1 were measured considerably higher than previously reported for municipal wastewaters. Temporal variability throughout the week (i.e., highest concentrations during weekdays) suggests these high concentrations are linked with industrial activity. Despite ≥90% removal during wastewater treatment, notable concentrations remained in tested effluent (62-892 ng L^-1). However, minimal impact on BPA concentrations in river water was observed for any of the effluents. The maximum BPA concentration found in river water was 117 ng L^-1 which is considerably lower than the current predicted no effect concentration of 1.6 μg L^-1. Nevertheless, analysis of digested sludge from sites which received these elevated BPA levels revealed average concentrations of 4.6 ± 0.3 and 38.7 ± 5.4 μg g^-1. These sludge BPA concentrations are considerably greater than previously reported and are attributed to the high BPA loading in influent wastewater. A typical sludge application regime to agricultural land would result in a predicted BPA concentration of 297 ng g^-1 in soil. Further studies are needed on the toxicological thresholds of exposed terrestrial organisms in amended soils to better assess the environmental risk here.

Risk assessment of pharmaceutically active compounds (PhACs) in the Klang River estuary, Malaysia

The concentration profile, distribution and risk assessment of pharmaceutically active compounds (PhACs) in the coastal surface water from the Klang River estuary were measured. Surface coastal water samples were extracted using offline solid phase, applying polymeric C18 cartridges as extraction sorbent and measuring with liquid chromatography mass spectrometry-mass spectrometry (LC MS-MS) technique. Extraction method was optimized for its recovery, sensitivity and linearity. Excellent recoveries were obtained from the optimized method with percentage of recoveries ranging from 73 to 126%. The optimized analytical method achieved good sensitivity with limit of detection ranging from 0.05 to 0.15 ng L^-1, while linearity of targeted compounds in the LC MS-MS system was more than 0.990. The results showed that amoxicillin has the highest concentration (102.31 ng L^-1) followed by diclofenac (10.80 ng L^-1) and primidone (7.74 ng L^-1). The percentage of contribution (% of total concentration) for the targeted PhACs is in the following order; amoxicillin (92.90%) > diclofenac (3.95%) > primidone (1.23%) > dexamethasone (0.75%) > testosterone (0.70%) > sulfamethoxazole (0.33%) > progesterone (0.14%). Environmental risk assessment calculated based on deterministic approach (the RQ method), showed no present risk from the presence of PhACs in the coastal water of Klang River estuary. Nonetheless, this baseline assessment can be used for better understanding on PhACs pollution profile and distribution in the tropical coastal and estuarine ecosystem as well as for future comparative studies.

Plant uptake and translocation of contaminants of emerging concern in soil

The advent of industrialization has led to the discovery of a wide range of chemicals designed for multiple uses including plant protection. However, after use, most of the chemicals and their derivatives end up in soil and water, interacting with living organisms. Plants, which are primary producers, are intentionally or unintentionally exposed to several chemicals, serving as a vehicle for the transfer of products into the food chain. Although the exposure of pesticides towards plants has been witnessed over a long time in agricultural production, other chemicals have attracted attention very recently. In this review, we carried out a comprehensive overview of the plant uptake capacity of various contaminants of emerging concern (CEC) in soil, such as pesticides, polycyclic aromatic hydrocarbons, perfluorinated compounds, pharmaceutical and personal care products, and engineered nanomaterials. The uptake pathways and overall impacts of these chemicals are highlighted. According to the literature, bioaccumulation of CEC in the root part is higher than in aerial parts. Furthermore, various factors such as plant species, pollutant type, and microbial interactions influence the overall uptake. Lastly, environmental factors such as soil erosion and temperature can also affect the CEC bioavailability towards plants.

Physicochemical Properties of Biochars Produced from Biosolids in Victoria, Australia

Some of the barriers associated with the land application of biosolids generated in wastewater treatment plants can be eliminated simply by converting the biosolids into biochar using a thermal conversion process called “pyrolysis”. In the current work, eight biosolids from four different wastewater treatment plants in southeast Melbourne, Victoria, Australia were collected and pyrolysed to produce biochars at two different temperatures (500 and 700 °C). In addition, characterisation studies were carried out on the biochars to obtain their physicochemical properties, which were subsequently compared with the properties of the parent biosolids. The major findings of the work demonstrated that biochars exhibited large decreases in DTPA-extractable metals such as Cd, Cu, and Zn, and also led to favorable changes in several chemical and physical characteristics (i.e., pH, Olsen P, electrical conductivity, and surface area) for agricultural land application compared to their original form (i.e., biosolids). Overall, the study suggests that there is great potential for converting biosolids to biochar using pyrolysis. This may not only improve the properties of biosolids for land application, but also has potential to reduce the risk to receiving environments and, furthermore, eliminate many of the costly elements associated with biosolids stockpiling and management.

Mechanism and kinetics of photochemical transformation of ketoprofen and its degradation intermediates

Ketoprofen, 2-(3-benzoylphenyl)-propionic acid, a widely used non-steroidal anti-inflammatory drug, is considered as an important water pollutant. Kinetics and mechanism of its photolytic transformation in aqueous solutions was studied experimentally and partial reaction steps were modelled by means of quantum chemistry methods. While the rate of ketoprofen photolysis was not significantly affected by its acid-base equilibrium, a marked influence of pH on the subsequent degradation reactions was observed. At pH 1.3, two oxygenated primary products were identified, that underwent fast photolysis. Deprotonated form of ketoprofen was transformed preferentially to ethylbenzophenone and further degradation proceeded substantially slower. Oxygen participated on photolytic processes both as a reactant and the triplet state quencher. The active involvement of water molecules in the reaction mechanism was investigated by comparative experiments in acetonitrile. The phototransformation mechanism proposed based on the experimental data corresponded well with the theoretical results.

Ecological risk evaluation of combined pollution of herbicide siduron and heavy metals in soils

Combined pollution of agrichemicals and heavy metals in urban lawn soils were commonly observed throughout the world, and the co-existed two chemicals could interact with each other both in environment behavior and toxic effect. However, little has been reported on the ecological risk of their combined pollution, especially in field due to lack of systematic methodology. In this study, four soils (C, N1, N2, N3) from two public parks in Beijing, China, with similar properties but contrasting heavy metal contaminated level were chosen to assess the ecological risks of co-existed herbicide siduron and heavy metals. Environmental behaviors of siduron in studied soils were investigated with batch experiments in lab, based on which the environmental exposure level of siduron was simulated with HYDRUS-1D. Results suggested that soil organic matter (SOM) rather than the co-existed heavy metals was the dominant factor affecting the fate and the accumulation of siduron in soils. Soil N2 with the highest SOM, showed the strongest tendency to retain siduron among the studied soils. Significant joint effect of siduron and heavy metals on cucumber root elongation was observed through lab experiments. Thus, the joint toxicity of siduron and heavy metals were calculated based on single toxicology data of them using independent action (IA) and concentration addition (CA) model. Then, the predicted no effect concentration (PNEC_soil) of siduron was calculated with equilibrium partitioning method and extrapolation techniques. The PNEC_soil of siduron was the lowest in heaviest heavy metal contaminated soil N3. The risk characterization ratios (RCR) of siduron in four soils were all >1. The highest RCR of siduron in soil N3 suggested that it was the joint toxicity of siduron and heavy metals to organisms determining the ecological risks of siduron in combined polluted soils.

Long-Term Exposure of Agricultural Soil to Veterinary Antibiotics Changes the Population Structure of Symbiotic Nitrogen-Fixing Rhizobacteria Occupying Nodules of Soybeans (Glycine max)

Antibiotics are entrained in agricultural soil through the application of manures from medicated animals. In the present study, a series of small field plots was established in 1999 that receive annual spring applications of a mixture of tylosin, sulfamethazine, and chlortetracycline at concentrations ranging from 0.1 to 10 mg · kg-1 soil. These antibiotics are commonly used in commercial swine production. The field plots were cropped continuously for soybeans, and in 2012, after 14 annual antibiotic applications, the nodules from soybean roots were sampled and the occupying bradyrhizobia were characterized. Nodules and isolates were serotyped, and isolates were distinguished using 16S rRNA gene and 16S to 23S rRNA gene intergenic spacer region sequencing, multilocus sequence typing, and RSα fingerprinting. Treatment with the antibiotic mixture skewed the population of bradyrhizobia dominating the nodule occupancy, with a significantly larger proportion of Bradyrhizobium liaoningense organisms even at the lowest dose of 0.1 mg · kg-1 soil. Likewise, all doses of antibiotics altered the distribution of RSα fingerprint types. Bradyrhizobia were phenotypically evaluated for their sensitivity to the antibiotics, and there was no association between in situ treatment and a decreased sensitivity to the drugs. Overall, long-term exposure to the antibiotic mixture altered the composition of bradyrhizobial populations occupying nitrogen-fixing nodules, apparently through an indirect effect not associated with the sensitivity to the drugs. Further work evaluating agronomic impacts is warranted.IMPORTANCE Antibiotics are entrained in agricultural soil through the application of animal or human waste or by irrigation with reused wastewater. Soybeans obtain nitrogen through symbiotic nitrogen fixation. Here, we evaluated the impact of 14 annual exposures to antibiotics commonly used in swine production on the distribution of bradyrhizobia occupying nitrogen-fixing nodules on soybean roots in a long-term field experiment. By means of various sequencing and genomic fingerprinting techniques, the repeated exposure to a mixture of tylosin, sulfamethazine, and chlortetracycline each at a nominal soil concentration of 0.1 mg · kg-1 soil was found to modify the diversity and identity of bradyrhizobia occupying the nodules. Nodule occupancy was not associated with the level of sensitivity to the antibiotics, indicating that the observed effects were not due to the direct toxicity of the antibiotics on bradyrhizobia. Altogether, these results indicate the potential for long-term impacts of antibiotics on this agronomically important symbiosis.

Effect of composting and soil type on dissipation of veterinary antibiotics in land-applied manures

The objective of this study was to determine the fate of commonly used veterinary antibiotics in their naturally excreted form when manure-based amendments are applied to soil. Beef cattle were administered sulfamethazine, tylosin, and chlortetracycline and dairy cows were treated with pirlimycin. The resulting manure was composted for 42 d under static or turned conditions and applied at agronomic N rates to sandy, silt, and silty clay loam soils and compared with amendment with corresponding raw manures in sacrificial microcosms over a 120-day period. Antibiotic dissipation in the raw manure-amended soils followed bi-phasic first order kinetics. The first phase half-lives for sulfamethazine, tylosin, chlortetracycline, and pirlimycin ranged from 6.0 to 18, 2.7 to 3.7, 23 to 25, and 5.5-8.2 d, respectively. During the second phase, dissipation of sulfamethazine was negligible, while the half-lives for tylosin, chlortetracycline, and pirlimycin ranged from 41 to 44, 75 to 144, and 87-142 d, respectively. By contrast, antibiotic dissipation in the compost-amended soils followed single-phase first order kinetics with negligible dissipation of sulfamethazine and half-lives of tylosin and chlortetracycline ranging from 15 to 16 and 49-104 d, respectively. Pirlimycin was below the detection limit in the compost-amended soils. After incubating 120 d, antibiotics in compost-amended soils (up to 3.1 μg kg^-1) were significantly lower than in manure-amended soils (up to 19 μg kg^-1, p < .0001), with no major effect of soil type on the dissipation. Risk assessment suggested that composting can reduce antibiotic resistance selection potential in manure-amended soils.

Effects of earthworm casts on sorption-desorption, degradation, and bioavailability of nonylphenol in soil

Up to hundreds of milligrams per kilogram (dry weight) of nonylphenol (NP) reportedly entered the soil and sediment through the agricultural reuse of biosolids, pesticide application, etc. Organic pollutants in soil could not only further trigger groundwater contamination via leaching (that highly depends upon sorption-desorption and degradation phenomena) but also harm food safety by crop uptake (that mainly rests with the bioavailability of pollutants in soil). Thus, we first investigated the effects of earthworm casts (EWCs) on the sorption-desorption, degradation, and bioavailability of NP in soil under laboratory microcosm conditions, and then, analyzed the FT-IR spectra of EWC and soil samples (with and without EWC). The application of EWC could notably increase the sorption capacity of soils for NP and in turn significantly inhibited the desorption of NP from soil; responsively lengthened the half-time of NP in the soil; and reduced the uptake and translocation of NP in tomato seedlings and promoted their growth during the first 3 weeks. Finally, FT-IR spectra of EWC and soil samples indicated that the application of EWC increased the content of N, P, and organic matter in soil.

Municipal sewage sludge compost promotes Mangifera persiciforma tree growth with no risk of heavy metal contamination of soil

Application of sewage sludge compost (SSC) as a fertilizer on landscaping provides a potential way for the effective disposal of sludge. However, the response of landscape trees to SSC application and the impacts of heavy metals from SSC on soil are poorly understood. We conducted a pot experiment to investigate the effects of SSC addition on Mangifera persiciforma growth and quantified its uptake of heavy metals from SSC by setting five treatments with mass ratios of SSC to lateritic soil as 0%:100% (CK), 15%:85% (S15), 30%:70% (S30), 60%:40% (S60), and 100%:0% (S100). As expected, the fertility and heavy metal concentrations (Cu, Zn, Pb and Cd) in substrate significantly increased with SSC addition. The best performance in terms of plant height, ground diameter, biomass and N, P, K uptake were found in S30, implying a reasonable amount of SSC could benefit the growth of M. persiciforma. The concentrations of Cu, Pb and Cd in S30 were insignificantly different from CK after harvest, indicating that M. persiciforma reduced the risk of heavy metal contamination of soil arising from SSC application. This study suggests that a reasonable rate of SSC addition can enhance M. persiciforma growth without causing the contamination of landscaping soil by heavy metals.

Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review

In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.