Antibiotics and antimycotics in waste water treatment plants: Concentrations, removal efficiency, spatial and temporal variations, prediction, and ecological risk assessment.

For investigating the spatial, temporal variations and assessing ecological risk of 10 antibiotics and 6 antimycotics, influent sewage water and treated effluent were collected during three different seasons in 19 waste water treatment plants of Tianjin. High performance liquid chromatography tandem mass spectrometry was used to analyze 16 substances. The concentration range of influent samples was not detected (nd) -547.94 ng/L and the concentration range of effluent samples was nd-52.97 ng/L. By calculating the removal efficiency, it was found that Ciprofloxacin (CIP), Ofloxacin (OFL) and Clotrimazole (CTR) were effectively removed. There were significant spatial and temporal differences, the concentration in the dry season was evidently higher than that in the wet and normal seasons, and the northeast was lower than that in the northwest and southeast. By establishing a data set of influent and effluent, the priority features were extracted by feature engineering, which were temperature and NH3-N. Under the condition of ensuring the best performance of the models, the influent model with 9 features and the effluent model with 4 features were established, and the quantitative relationship between the above features and concentration was obtained through partial dependence analysis. Except for Moxifloxacin (MOX), Norfloxacin (NOR) and OFL in the influent samples, the RQ values for other antibiotics and antimycotics were less than 0.1. Among the effluent samples, only NOR had an RQ value greater than 0.1, and OFL, MOX, and Pefloxacin (PEF) had RQ values between 0.01 and 0.1. Comparing the observations and predictions individual RQ values, the predictions were ideal and matched the observations. This work effectively assessed environmental impact and provided a valuable reference for evaluating antibiotics and antimycotics ecological toxicity.

Antibiotics in sewage treatment plants, receiving water bodies and groundwater of Chennai city and the suburb, South India: Occurrence, removal efficiencies, and risk assessment.

The presence of antibiotics in the aqueous environment can alter the water microbiome, inducing antimicrobial resistance genes. Hence, the occurrence of 18 antibiotics belonging to sulfonamides, fluoroquinolones, tetracyclines, phenicols, and macrolides classes were investigated in surface water, groundwater, and sewage treatment plants in Chennai city and the suburbs. Fluoroquinolones had the maximum detection frequency in both influent and effluent samples of urban and suburban STPs, with ofloxacin and ciprofloxacin showing the highest influent concentrations. Erythromycin was the predominant antibiotic in surface water samples with an average concentration of 194.4 ng/L. All the detected antibiotic concentrations were higher in the Buckingham Canal compared to those in Adyar and Cooum rivers, possibly due to direct sewer outfalls in the canal. In groundwater samples, ciprofloxacin showed the highest levels with an average of 20.48 ng/L and the concentrations were comparable to those of surface water. The average sulfamethazine concentration in groundwater (5.2 ng/L) was found to be slightly higher than that of the surface water and much higher than the STP influent concentrations. High levels of ciprofloxacin and sulfamethazine in groundwater may be because of their high solubility and wide use. Moreover, erythromycin was completely removed after treatment in urban STPs; FQs showed relatively lesser removal efficiency (2.4-54%) in urban STPs and (8-44%) in suburban STP. Tetracyclines and phenicols were not detected in any of the samples. Ciprofloxacin and azithromycin in surface water pose a high risk in terms of estimated antibiotic resistance. This study revealed that the measured surface water concentration of antibiotics were 500 times higher for some compounds than the predicted calculated concentrations from STP effluents. Therefore, we suspect the direct sewage outlets or open drains might play an important role in contaminating surface water bodies in Chennai city.

An automated on-line turbulent flow liquid-chromatography technology coupled to a high resolution mass spectrometer LTQ-Orbitrap for suspect screening of antibiotic transformation products during microalgae wastewater treatment.

The evaluation of wastewater treatment capabilities in terms of removal of water pollutants is crucial when assessing water mitigation issues. Not only the monitoring of target pollutants becomes a critical point, but also the transformation products (TPs) generated. Since these TPs are very often unknown compounds, their study in both wastewater and natural environment is currently recognized as a tedious task and challenging research field. In this study, a novel automated suspect screening methodology was developed for a comprehensive assessment of the TPs generated from nine antibiotics during microalgae water treatment. Three macrolides (azithromycin, erythromycin, clarithromycin), three fluoroquinolones (ofloxacin, ciprofloxacin, norfloxacin) and three additional antibiotics (trimethoprim, pipemidic acid, sulfapyridine) were selected as target pollutants. The analysis of samples was carried out by direct injection in an on-line turbulent flow liquid chromatography-high resolution mass spectrometry (TFC-LC-LTQ-Orbitrap-MS/MS) system, followed by automatic data processing for compound identification. The screening methodology allowed the identification of 40 tentative TPs from a list of software predicted intermediates created automatically. Once known and unknown TPs were identified, degradation pathways were suggested considering the different mechanisms involved on their formation (biotic and abiotic). Results reveal microalgae ability for macrolide biotransformation, but not for other antibiotics such as for fluoroquinolones. Finally, the intermediates detected were included into an in-house library and applied to the identification of tentative TPs in real toilet wastewater treated in a microalgae based photobioreactor (PBR). The overall approach allowed a comprehensive overview of the performance of microalgae water treatment in a fast and reliable manner: it represents a useful tool for the rapid screening of wide range of compounds, reducing time invested in data analysis and providing reliable structural identification.

Distribution, fate, and risk assessment of antibiotics in five wastewater treatment plants in Shanghai, China.

The project studied the occurrence, fate, and seasonal variation of 14 antibiotics, from five wastewater treatment plants (WWTPs) in Shanghai. The results indicated that ofloxacin, sulfamethoxazole, and oxytetracycline were the predominant antibiotics, with maximum concentrations of 1208.20, 959.13, and 564.30 ng/L in influents, while 916.88, 106.60, and 337.81 ng/L in effluents, respectively. The level of antibiotics in WWTPs obviously varied with seasonal changes, and higher detectable frequencies and concentrations were found in winter. The daily mass loads per capita of amoxicillin, enrofloxacin, and oxytetracycline in the study were all higher than those in other regions/countries, such as Hong Kong, Australia, and Italy. The elimination of antibiotics through these WWTPs was incomplete, and a wide range of removal efficiencies during the different treatment process and seasons were observed (-500.56 to 100 % in winter and -124.24 to 94.21 % in summer). Sulfonamides were relatively easy to be removed in WWTPs and the ultraviolet (UV) process can effectively improve the removal efficiency. Risk assessment of antibiotics in effluents was estimated. Only AMOX's hazard quotient (HQ) was higher than 0.01. Even though the environmental risks in the study were estimated to be low, the potential negative effects on aquatic ecosystems should call our attention as continually discharge in the long term.

Co-sorption of ofloxacin and Cu(II) in soils before and after organic matter removal.

Various mechanisms play roles simultaneously for antibiotic sorption on solid particles. Previous studies simply emphasized mechanisms that match the increased or decreased antibiotic sorption by metal ions, without a general concept including these diverse mechanisms in their co-sorption. We observed both increased and decreased OFL and Cu(II) sorption in their co-sorption system. The comparison of the sorption coefficients of primary adsorbate (Kd(pri)) and co-adsorbate (Kd(co)) suggested that enhanced sorption occurred at high Kd(pri) region (low primary adsorbate concentration). Competitive sorption was observed when Kd(pri) was decreased to a certain value depending on solid particle properties. We thus summarized that if the adsorbates were introduced with low concentrations, OFL (such as hydrophobic region in solid particles) and Cu(II) (such as inner-sphere complexation sites) occupied their unique high-energy sorption sites. Cu(II) complexed with the adsorbed OFL, and OFL bridged by the adsorbed Cu(II) promoted the sorption for both chemicals. With the increased concentrations, the adsorbates spread to some common sorption sites with low sorption energy, such as cation exchange and electrostatic attraction region. The overlapping of Cu(II) and OFL on these sorption sites resulted in competitive sorption at high concentrations. The previously reported apparently increased or decreased sorption in antibiotic-metal ion co-sorption system may be only a part of the whole picture. Extended study on the turning point of decreased and increased sorption relating to water chemistry conditions and solid particle properties will provide more useful information to predict antibiotic-metal ion co-sorption.

Competitive sorption and desorption behavior for three fluoroquinolone antibiotics in a wastewater treatment wetland soil.

Significant amounts of pharmaceuticals are discharged into the environment through wastewater effluent. Sorption has been shown to be a significant aqueous removal pathway for many of these compounds. Competition between ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR) and their sorption to, and desorption from, a surrogate Louisiana wastewater treatment wetland soil were investigated to gain insight into the fate and transport of the pollutants within wastewater treatment wetlands. This study was undertaken in the context of a treatment wetland that continuously receives pharmaceuticals. Therefore it is important to understand the total capacity of this soil to sorb these compounds. Sorption to this treatment wetland soil was found to provide a major and potentially long-term removal pathway for these antibiotics from wastewater. LogK(F) values for all three compounds were between 4.09 and 3.90 for sorption and 4.24 and 4.05 microg(1-1/)(n)(cm(3))(1/)(n)g(-1) for desorption. The compounds were sorbed in amounts ranging from 60% to 90% for high and low loading, respectively. The majority of the compounds were sorbed to the soil within the first 20h, indicating that treatment wetland may not need long retention times (weeks to months) in order to remove these compounds. Sorption K(D) values for competition (20 ppm of each compound for 60 ppm of total fluoroquinolones) ranged from 2300 to 3800 cm(3)g(-1) which is between both the 20 (4300-5800 cm(3)g(-1)) and 60 (1300-3000 cm(3)g(-1)) ppm single compound K(D) values, indicating that there is competition between these three compound for sorption sites. Sorption and desorption data (single component and mixture) collectively provide the following evidence: (1) NOR and, to a lesser extent, CIP outcompete OFL for sorption sites, (2) OFL sorbes to its share of "quality" sorption sites, and (3) competition only occurs for lesser "quality" binding sites.