Negative effects of environmental antibiotics on non-target organisms were observed in studies at various levels of the biological organization. Yet, studies combining the effects at multiple levels were required to interpret their ecological frequencies in a broader context. Currently, effects of sulfamethoxazole (SMX) was studied on the amphipod Hyalella azteca which is important in ecological stability. At the biochemical level, effects on the antioxidant capacities showed stimulation with an inverse U-shaped change over the concentrations. The stimulation was greater in male than in females. Effects on the oxidative stress showed a U-shaped change which included stimulation and inhibition in males, and solely stimulation in females. The stimulation was less in males than in females. Effects on acetylcholinesterase (AChE) activities in both sexes were well correlated with those on oxidative stress (p < 0.05). At the individual level, effects on the body weight showed an inverse U-shaped change over concentrations, and the stimulation was greater in males than in females. The stimulations were significantly correlated with the male oxidative stress (p < 0.01), and male (p < 0.1) and female AChE activities (p < 0.05). Effects of SMX on the pre-copulation behavior also showed an inverse U-shaped change which correlated with male and female antioxidant capacities (p < 0.05) and the male body weight (p < 0.05). At the population level, effects on the reproduction showed an inverse U-shaped change over concentrations, and they significantly correlated with the male body weight (p < 0.05) and the pre-copulation behavior (p < 0.05). Summing up, SMX provoked simultaneous disturbances on the amphipod at multiple levels with sex-dependent responses.

Beef cattle feedyards have been identified as sources of large amounts of particulate matter (PM) which may transport affiliated chemicals including steroids, beta agonists, and antibiotics from feedyards into the environment. This study is the first to examine persistence of PM-affiliated pharmaceuticals downwind of feedyards using multiple downwind samples collected at increasing distances from feedyard boundaries (n = 5). Concentrations of antibiotics and ractopamine per gram of PM remained consistent at all downwind locations (out to 4.8 km) whereas concentrations per m³ air decreased significantly at distances between 0.1 and 0.7 km downwind, corresponding to significant decreases in mass of PM. Monensin was present in the highest concentrations of any measured pharmaceutical, with concentrations of 37 μg/g PM (376 ng/m³) air in samples collected within 0.1 km downwind of feedyards. Total copy count of tetracycline resistance genes (tetW, tetQ, tetO, tetM, tetL, and tetB) were also significantly increased in samples collected within 0.1 km downwind of feedyards (10⁶ copies) as compared to samples collected upwind (10³ copies) and farther downwind (10⁴ copies) of feedyard boundaries. These results suggest that transport of pharmaceutical-laden PM into the terrestrial environment is occurring primarily via PM deposition within 0.7 km of the feedyard, while aerial transport persists over longer distances (>4.8 km).

The Deception Island, located in Maritime Antarctica, is a volcanic island with geothermal activity and one of the most visited by tourists. However, the extent of the anthropogenic impact remains largely unknown and the factors shaping the resistance/tolerance mechanisms in the microbiomes from Whalers Bay ecosystems have never been investigated. In this context, this study aimed to reveal the resistome profiles of Whalers Bay sediments and correlate them with environmental factors. Samples were collected at four sites during the summer 2014/2015 along a transect of 27.5 m in the Whalers Bay sediments. DNA isolated from sediment samples was sequenced using the Illumina HiSeq platform. Bioinformatic analyses allowed the assembly of contigs and scaffolds, prediction of ORFs, and taxonomic and functional annotation using NCBI RefSeq database and KEGG orthology, respectively. Microorganisms belonging to the genera Psychrobacter, Flavobacterium and Polaromonas were shown to dominate all sites, representing 60% of taxonomic annotation. Arsenic (As), copper (Cu) and iron (Fe) were the most abundant metal resistance/tolerance types found in the microbiomes. Beta-lactam was the most common class related to antibiotics resistance/tolerance, corroborating with previous environmental resistome studies. The acridine class was the most abundant amongst the biocide resistance/tolerances, related to antiseptic compounds. Results gathered in this study reveal a repertoire of resistance/tolerance classes to antibiotics and biocides unusually found in Antarctica. However, given the volcanic nature (heavy metals-rich region) of Deception Island soils, this putative impact must be viewed with caution.

The development of high-efficiency adsorbents and the exploration of their adsorption mechanisms are major challenges in environmental remediation. Herein, MIL-100 was prepared, characterized, and utilized for the adsorptive removal of diclofenac sodium (DCF) from aqueous solutions. A high monolayer adsorption capacity of 773 mg g⁻¹ was recorded. The adsorption mechanism was proposed based on different contributions of two types of pore structure of MIL-100 to the adsorption of DCF from aqueous solutions according to the experimental results and theoretical calculation. During adsorption process, DCF (5.2 × 7.4 × 10.3 Å) diffused through the free area of hexagonal pores (8.6 × 8.6 Å) into the cages of MIL-100, whilst it was adsorbed by the pentagonal pores (4.8 × 5.8 Å) preferentially. Internal mass transfer resistance, which was identified as one of the dominant rate-limiting steps by the mass transfer resistance kinetic models based on the Sips model, will be derived from the diffusion process, which was affected by the size-sieving effect of the pore structure of MIL-100. The successful diffusion of DCF into the interior of MIL-100 and the stable configuration between MIL-100 and DCF accounted for the high adsorption capacity. The capture of DCF into MIL-100 also resulted in the pore size distribution variation of adsorbent, which provided vital experimental evidence for the proposed mechanism. This study may offer deeper insights into other pollutants removal by metal-organic frameworks type adsorbents.

The impact of commonly-used livestock antibiotics on soil nitrogen transformations under varying redox conditions is largely unknown. Soil column incubations were conducted using three livestock antibiotics (monensin, lincomycin and sulfamethazine) to better understand the fate of the antibiotics, their effect on nitrogen transformation, and their impact on soil microbial communities under aerobic, anoxic, and denitrifying conditions. While monensin was not recovered in the effluent, lincomycin and sulfamethazine concentrations decreased slightly during transport through the columns. Sorption, and to a limited extent degradation, are likely to be the primary processes leading to antibiotic attenuation during leaching. Antibiotics also affected microbial respiration and clearly impacted nitrogen transformation. The occurrence of the three antibiotics as a mixture, as well as the occurrence of lincomycin alone affected, by inhibiting any nitrite reduction, the denitrification process. Discontinuing antibiotics additions restored microbial denitrification. Metagenomic analysis indicated that Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi were the predominant phyla observed throughout the study. Results suggested that episodic occurrence of antibiotics led to a temporal change in microbial community composition in the upper portion of the columns while only transient changes occurred in the lower portion. Thus, the occurrence of high concentrations of veterinary antibiotic residues could impact nitrogen cycling in soils receiving wastewater runoff or manure applications with potential longer-term microbial community changes possible at higher antibiotic concentrations.

Antibiotics are introduced into agricultural fields by the application of manure or biosolids, or via irrigation using reclaimed wastewater. Antibiotics can enter the terrestrial food chains through plant uptake, which forms an alternative pathway for human exposure to antibiotics. However, previous studies mainly focused on detecting residues of the parent antibiotics, while ignoring the identification of antibiotics transformation products in plants. Here, we evaluated the uptake and metabolism of clarithromycin (CLA) and sulfadiazine (SDZ) in lettuce under controlled hydroponic conditions. The antibiotics and their metabolites were identified by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS/MS) and ultra-performance liquid chromatograph Micromass triple quadrupole mass spectrometry (UPLC−QqQ−MS/MS). The structure of CLA, SDZ and N-acetylated SDZ were confirmed with synthesized standards, verifying the reliability of the identification method. Eight metabolites of CLA and two metabolites of SDZ were detected in both the leaves and roots of lettuce. The metabolites of CLA included phases I and II transformation products, while only phase II metabolites of SDZ were observed in lettuce. The proportion of CLA metabolites was estimated to be greater than 70%, indicating that most of the CLA was metabolized in plant tissues. The proportion of SDZ metabolites was lower than 12% in the leaves and 10% in the roots. Some metabolites might have the ability to increase or acquire antibacterial activity. Therefore, in addition to the parent compounds, metabolites of antibiotics in edible vegetables are also worthy of study for risk assessment and to determine the consequences of long-term exposure.

The abuse of antibiotics has caused the propagation of antibiotic resistance genes (ARGs) in aquaculture systems. Although the recirculating systems have been considered as a promising approach for preventing the coastal water pollution of antibiotics and ARG, rare information is available on the distribution and proliferation of ARGs in the recirculating mariculture system. This study firstly investigated the proliferation of ARGs in coastal recirculating mariculture systems. Ten subtypes of ARGs including tet (tetB, tetG, tetX), sul (sul1, sul2), qnr (qnrA, qnrB, qnrS), and erm (ermF, ermT) were detected. The absolute abundances of the ARGs detected in the mariculture farm were more than 1 × 10⁴ copies/mL. The sulfonamide resistance genes (sul1 and sul2) were the most abundant ARGs with the abundance of 3.5 × 10⁷–6.5 × 10¹⁰ copies/mL. No obvious correlation existed between the antibiotics and ARGs. Some bacteria were positively correlated with two or more ARGs to indicate the occurrence of multidrug resistance. The fluidized-bed biofilter for wastewater treatment in the recirculating system was the main breeding ground for ARGs while the UV sterilization process could reduce the ARGs. The highest flux of ARGs (6.5 × 10²¹ copies/d) indicated that the discharge of feces and residual baits was the main gateway for ARGs in the recirculating mariculture system to enter the environments.

Manmade antibiotics are emerging organic pollutants widely detected in the marine environment. In this study, 14 out of 19 target antibiotics were detected in corals collected from coastal and offshore regions in the South China Sea. The average total antibiotic concentrations (∑19ABs) in the two regions were similar: 28 ng/g for coastal corals and 31 ng/g for offshore corals, based on dry tissue weight (dw). Fluoroquinolones (FQs) were predominant antibiotics in the coastal corals (mean ∑FQs: 18 ng/g dw), while sulfonamides (SAs) predominated in the offshore corals (mean ∑SAs: 23 ng/g dw). However, corals living in coastal regions tend to excrete more mucus than corals in offshore habitat. We found 53% by average of ∑19ABs in the mucus of the coastal corals; while in offshore corals, most antibiotics (88% by average) were accumulated in the tissues. In addition, the tissue-mucus mass distribution differs among individual antibiotics. Sulfonamides were mainly accumulated in tissues while fluoroquinolones were present mainly in mucus. The results of this study suggest that mucus played an important role in the bioaccumulation of antibiotics by corals. It may resist the bioaccumulation of antibiotics by coral tissue, especially for the coastal corals. Additionally, corals were compared with other marine biotas in the study area and found to be more bioaccumulative towards antibiotics.

Coexistence of antibiotics/heavy metals and the overexpression of resistance genes in the vermicompost has become an emerging environmental issue. Little is known about the interaction and correlation between chemical pollutants and biological macromolecular compounds. In this study, three typical vermicompost samples were selected from the Yangtze River Delta region in China to investigate the antibiotic, heavy metal and corresponding antibiotic resistance genes (ARGs) and heavy metal resistance genes (HRGs). The results indicated the prevalence of tetracycline (TC), copper (Cu), zinc (Zn), cadmium (Cd), corresponding TC-resistance genes (tetA, tetC, tetW, tetM, tetO, and tetS) and HRGs (copA, pcoA, cusA, czcA, czcB, and czcR) in the three vermicompost samples. In addition, the ARG level was positively associated with the water-soluble TC fraction in the vermicompost, and it was same between the HRG abundance and exchangeable heavy metal content (p < 0.05). Moreover, a positive correlation was found between ARG and HRG abundance in the vermicompost samples, suggesting a close regulation mechanism involving the expression of both genes. The result obtained here could provide new insight into the controlling risk of heavy metals, TC, and relevant resistance genes mixed contamination in the vermicompost.

Land application of animal manure could change the profiles of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs) and bacterial communities in receiving soils. Using high-throughput real-time quantitative PCR and 16S rRNA amplicon sequencing techniques, this study investigated the ARGs and bacterial communities in field soils under various crop (corn and pasture) and manure (swine and dairy) managements, which were compared with those of two non-manured reference soils from adjacent golf course and grassland. In total 89 unique ARG subtypes were found in the soil samples and they conferred resistance via efflux pump, cellular protection and antibiotic deactivation. Compared to the ARGs in the golf course and grassland soils (28 and 34 subtypes respectively), manured soils generally had greater ARG diversity (36–55 subtypes). Cornfield soil frequently receiving raw swine manure had the greatest ARG abundance. The short-term (one week) application of composted and liquid swine manures increased the diversity and total abundance of ARGs in cornfield soils. Intriguingly the composted swine manure only marginally increased the total abundance of ARGs, but substantially increased the number of ARG subtypes in the cornfield soils. The network analysis revealed three major network modules in the co-occurrence patterns of ARG subtypes, and the hubs of these major modules (intl1-1, vanC, and pncA) may be candidates for selecting indicator genes for surveillance of ARGs in manured soils. The network analyses between ARGs and bacteria taxa revealed the potential host bacteria for the detected ARGs (e.g., aminoglycoside resistance gene aacC4 may be mainly carried by Acidobacteriaceae). Overall, this study highlighted the potentially varying impact of various manure management on antibiotic resistome and microbiome in cornfield and pasture soils.