Warming and acidification are expected impacts of climate change to the marine environment. Besides, organisms that live in coastal areas, such as bivalves, can also be exposed to anthropogenic pollutants like pharmaceuticals (PhACs) and endocrine disrupting compounds (EDCs). In this study, the effects of warming and acidification on the bioconcentration, metabolization and depuration of five PhACs (sotalol, sulfamethoxazole, venlafaxine, carbamazepine and citalopram) and two EDCs (methylparaben and triclosan) were investigated in the mussel species (Mytilus galloprovincialis), under controlled conditions. Mussels were exposed to warming and acidification, as well as to the mixture of contaminants up to 15.7 μg L−1 during 20 days; followed by 20 days of depuration. All contaminants bioconcentrated in mussels with levels ranging from 1.8 μg kg−1 dry weight (dw) for methylparaben to 12889.4 μg kg−1 dw for citalopram. Warming increased the bioconcentration factor (BCF) of sulfamethoxazole and sotalol, whereas acidification increased the BCF of sulfamethoxazole, sotalol and methylparaben. In contrast, acidification decreased triclosan levels, while both stressors decreased venlafaxine and citalopram BCFs. Warming and acidification facilitated the elimination of some of the tested compounds (i.e. sotalol from 50% in control to 60% and 68% of elimination in acidification and warming respectively). However, acidification decreased mussels' capacity to metabolize contaminants (i.e. venlafaxine). This work provides a first insight in the understanding of aquatic organisms' response to emerging contaminants pollution under warming and acidification scenarios.

The knowledge of gene-chemical interaction can be used to derive toxicological mechanism of chemical pollutants, therefore, it might be useful to discriminate chemicals with different mechanisms. In this study, three narcotic chemicals (4-chlorophenol (4-CP), 3, 4-dichloroaniline (DCA) and 2, 2, 2-trichloroethanol (TCE)) and three specific acting chemicals (triclosan (TCS), clarithromycin (CLARY), sulfamethoxazole (SMX)) were assessed by Escherichia coli (E. coli) genome-wide knockout screening. 66, 97, 88, 144, 198 and 180 initial robust hits were identified by exposure to 4-CP, DCA, TCE, TCS, CLARY and SMX with two replicates at the concentration of IC50, respectively. The average fold change values of responsive mutants to the three narcotic chemicals were smaller than the three specific acting chemicals. The common gene ontology (GO) term of biological process enriched by the three narcotic chemicals was “response to external stimulus” (GO: 0009605). Other GO terms like “lipopolysaccharide biosynthetic process” (induced by 4-CP) and “purine nucleotide biosynthetic process” (induced by DCA) were also influenced by the narcotic chemicals. The toxic target of three known specific acting chemicals could be validated by GSEA of responsive genes. Four genes (flhC, fliN, fliH and flhD) might serve as potential biomarkers to distinguish narcotic chemicals and specific acting chemicals. The E. coli functional genomic approach presented here has shown great potential not only for the molecular mechanistic screening of chemicals, rather it can discriminate chemicals based on their mode-of-action.

Metabolism of pharmaceuticals in plants is important to evaluate their fate and accumulation in vegetables, and subsequently the risks to human health. However, limited knowledge is available to evaluate metabolism of pharmaceuticals in plants due to the lack of appropriate research approaches. In this study, radish was selected as a model plant to investigate metabolism of pharmaceuticals in intact plants (in vivo) growing in hydroponic solution and in plant tissue enzyme extracts (in vitro). For caffeine, six phase-I demethylation metabolites identified in the intact radish plant were also found in the plant enzyme extracts. After 7 days of in vivo exposure, the amount of the identified metabolites was about 5.4 times greater than the parent compound caffeine in radish roots. Furthermore, the metabolism potential of fifteen pharmaceuticals in radish was evaluated on the basis of mass balance. After 7 days of hydroponic exposure, oxytetracycline, trimethoprim, carbamazepine, lincomycin, monensin and tylosin manifested relatively less extent of metabolism with the mass recoveries ranging from 52.3 to 78.2%. In contrast, 17 β-estradiol, sulfamethoxazole, sulfadiazine, estrone, triclosan, acetaminophen, caffeine, carbadox and lamotrigine underwent extensive metabolism with only 3.0 to 32.1% of the parent compound recovered. In the in vitro system, 17 β-estradiol, estrone, triclosan, oxytetracycline, acetaminophen, sulfadiazine and sulfamethoxazole were readily metabolized in radish root enzyme extracts with 1.8 to 34.0% remaining after 96-h exposure. While in the leaf enzyme extracts, only triclosan was rapidly metabolized with 49.2% remaining, and others pharmaceuticals were ≥60%, indicating that the varying extents of metabolism occurred in different plant parts. This study highlights the importance of pharmaceutical metabolism in plants, and suggests that plant tissue enzyme extracts could serve as an alternative tool to assess pharmaceutical metabolism in plants.

The combination of emerging antibiotic resistance and lack of discovery of new antibiotic classes poses a threat to future human welfare. Antibiotics are administered to livestock at a large scale and these may enter the environment by the spreading of manure on agricultural fields. They may leach to groundwater, especially in the Netherlands which has some of the most intensive livestock farming and corresponding excessive manure spreading in the world. This study investigates the presence of antibiotics in groundwater in two regions with the most intensive livestock farming in the Netherlands. If so, the hydrochemical conditions were further elaborated. Ten multi-level wells with in total 46 filters were sampled, focusing on relatively young, previously age-dated groundwater below agricultural fields. Twenty-two antibiotics were analyzed belonging to the following antibiotic groups: tetracyclines, sulfonamides, trimethoprims, β-lactams, macrolides, lincosamides, quinolones, nitrofurans and chloramphenicol. The samples were analyzed for these antibiotics by LC-MS/MS ESI-POS/NEG (MRM) preceded by solid phase extraction which resulted in importantly low detection limits. Six antibiotics were found above detection limits in 31 filters in seven wells: sulfamethazine, sulfamethoxazole, lincomycin, chloramphenicol, ciprofloxacin, and sulfadiazine. The concentrations range from 0.3 to 18 ng L−1. Sulfonamides were detected at all measured depths down to 23 meters below surface level with apparent groundwater ages up to 40 years old. No antibiotics were detected below the nitrate/iron redox cline, which suggests that the antibiotics might undergo degradation or attenuation under nitrate-reducing redox conditions. This study provides proof that antibiotics are present in groundwater below agricultural areas in the Netherlands due to the spreading of animal manure.

Antibiotics have been widely used in human and veterinary medicine to both treat and prevent disease. Due to their high water solubility and low bioavailability, many antibiotic residues have been found in aquatic environments. Fish are an indispensable link between the environmental pollution and human health. However, the chronic effects of environmental concentrations of antibiotics in fish have not been thoroughly investigated. Sulfamethoxazole (SMX) and oxytetracycline (OTC) are frequently detected in aquatic environments. In this study, zebrafish were exposed to SMX (260 ng/L) and OTC (420 ng/L) for a six-week period. Results indicated that exposure to antibiotics did not influence weight gain of fish but increased the metabolic rate and caused higher mortality when treated fish were challenged with Aeromonas hydrophila. Furthermore, exposure to antibiotics in water resulted in a significant decrease in intestinal goblet cell numbers, alkaline phosphatase (AKP), acid phosphatase (ACP) activities, and the anti-oxidant response while there was a significant increase in expression of inflammatory factors. Antibiotic exposure also disturbed the intestinal microbiota in the OTC-exposed group. Our results indicated that environmental antibiotic concentrations can impair the gut health of zebrafish. The potential health risk of antibiotic residues in water should be evaluated in the future.

In recent years, numerous studies have reported the prevalence of organic micropollutants in natural waters. There is an increasing interest in assessing the occurrence and transport of these contaminants in groundwater because a large number of people in the United States rely on groundwater for their drinking water. However, commonly used mass-spectrometry-based analytical methods are expensive and time-consuming. The enzyme-linked immunosorbent assay (ELISA) method offers an inexpensive analytical alternative that provides semi-quantitative results in a relatively quick timeframe. We investigated the use of ELISA for two commonly detected micropollutants, sulfamethoxazole (SMX) and carbamazepine (CBZ), in groundwater collected as part of two different studies, one in Minnesota and the other in Iowa. The ELISA results were compared with two mass-spectrometry-based methods: (1) direct aqueous injection-high performance liquid chromatography/tandem mass spectrometry (HPLC) and (2) online solid-phase extraction with liquid chromatography/electrospray ionization-mass spectrometry (SPE LC). Differences in SMX and CBZ observations between ELISA and both HPLC and SPE LC were analyzed using the Paired Prentice-Wilcoxon test. Estimates of bias and limits of agreement between paired observations also were calculated. The SMX determinations by ELISA yielded results that were 30 and 14% greater than HPLC and SPE LC, respectively. The CBZ determinations by ELISA yielded results that were 25 and 9% greater than HPLC and SPE LC, respectively. The ELISA determinations were in presence-absence agreement with HPLC for 83% of samples for SMX and CBZ; and with SPE LC for 76 and 80% of samples for SMX and CBZ, respectively. Results indicate that ELISA for SMX and CBZ is a reliable and cost effective screening-tool alternative to more commonly used mass spectrometry-based analytical methods.

Environmental antimicrobial resistance (AMR) has drawn increasing attention due to its great risk to human health. The aim of this study was to investigate AMR and genotyping of Vibrio parahaemolyticus isolates (n = 114) recovered from shrimp mariculture environment in China. The isolates exhibited a high rate of resistance to streptomycin (78.9%), ampicillin (64.9%) and gentamicin (53.5%). Furthermore, multi-drug resistance was highly prevalent (61.4%), in which 95.9% of these ampicillin-resistant isolates were primarily mediated by blaCARB-17. Surprisingly, doxycylcine, florfenicol, and trimethoprim/sulfamethoxazole (TMP/SMZ) resistance genes occurred in susceptible isolates. Moreover, 114 isolates were grouped into unique pulsed field gel electrophoresis patterns. These findings suggest the need for the prudent use of antimicrobial agents on mariculture farms, in order to control the dissemination of antimicrobial resistant V. parahaemolyticus.

Microplastics and sulfamethoxazole coexist ubiquitously in the marine environment, and microplastics tend to sorb organic pollutants from the surrounding environment. Here, the sorption kinetics and isotherms of sulfamethoxazole on polyethylene (PE) microplastics closely fitted a pseudo-second-order model (R2 = 0.98) and linear model (R2 = 0.99), respectively, indicating that the sorption process was partition-dominant interaction. The main binding mechanism was possibly the van der Waals interaction for hydrophilic sulfamethoxazole onto hydrophobic PE microplastics. The effects of pH, dissolved organic matter and salinity on sorption behavior were also studied. The sorption behavior of sulfamethoxazole on PE microplastics was not significantly influenced by pH and salinity, probably because the electrostatic repulsion played a minor role. In addition, the negligible effect of dissolved organic matter was attributed to the greater affinity of sulfamethoxazole to PE microplastics than to dissolved organic matter. Our results demonstrated that PE microplastics may serve as a carrier for sulfamethoxazole in the aquatic environment.

Concentrations of selected antibiotic compounds from different groups were measured in sediment samples (14 analytes) and in near-bottom water samples (12 analytes) collected in 2011–2013 from the southern Baltic Sea (Polish coastal zone). Antibiotics were determined at concentration levels of a few to hundreds of ng g−1 d.w. in sediments and ng L−1 in near-bottom waters. The most frequently detected compounds were sulfamethoxazole, trimethoprim, oxytetracycline in sediments and sulfamethoxazole and trimethoprim in near-bottom waters. The occurrence of the identified antibiotics was characterized by spatial and temporal variability. A statistically important correlation was observed between sediment organic matter content and the concentrations of sulfachloropyridazine and oxytetracycline. Risk assessment analyses revealed a potential high risk of sulfamethoxazole contamination in near-bottom waters and of contamination by sulfamethoxazole, trimethoprim and tetracyclines in sediments. Both chemical and risk assessment analyses show that the coastal area of the southern Baltic Sea is highly exposed to antibiotic residues.

The aim of the present study was to evaluate the sorption and desorption of sulfamethoxazole (SMX), propranolol (PRP) and sertraline (SER) by polyethylene (PE) microplastics in water. After the 96 h mixture, the sorption percentages of pharmaceuticals on PE microplastics decreased according to the following order: SER (28.61%) > PRP (21.61%) > SMX (15.31%). The sorption kinetics were fitted well with the pseudo-second-order model. Both linear and Freundlich models were able to describe the sorption isotherm. The results suggest that the sorption process of the pharmaceuticals may be adequately described by their hydrophobicity and electrostatic interactions. The desorption results showed that 8% and 4% of PRP and SER, respectively, were released from the microplastics within 48 h, but the sorption of SMX was irreversible. The results indicate the potential risks of PRP and SER for bioaccumulation in aquatic organisms via ingestion of the microplastics in aquatic environments.