Florfenicol is one of the most-used antimicrobial agents in global fish farming. Nevertheless, in most countries, its use is not conducted in accordance with good practices. The aim of this work was to evaluate the leaching of florfenicol from coated fish feed into the water. Analytical methods were developed and validated for the quantitation of florfenicol in medicated feed and water by UHPLC-MS/MS. Florfenicol residues in the water were quantified after 5- and 15-min exposures of the medicated feed in the water at 22 and 28 °C and at pH 4.5 and 8.0. The influence of pellet size and three coating agents (vegetable oil, carboxymethylcellulose, and low-methoxylated pectin) on the leaching of the drug was also assessed. Pellet size, coating agent, water temperature, and time of exposure significantly (p < 0.05) affected florfenicol leaching, while water pH did not interfere with the leaching. Coating with vegetable oil was the most efficient method to reduce florfenicol leaching, while coating with carboxymethylcellulose presented the highest leaching (approximately 60% after 15 min at 28 °C). Thus, the coating agent has a significant effect on the florfenicol leaching rate and, consequently, on the necessary dose of the drug to be administered. Moreover, it is worth mentioning that higher florfenicol leaching will pose a greater risk to environmental health, specifically in terms of the development of bacteria resistant to florfenicol. Additional studies are needed with other polymers and veterinary drugs used in medicated feed for fish farming.

Studies are underway to gather information about the mode of action (MOA) of emerging pollutants that could guide practical environmental decision making. Previously, we showed that propranolol, an active pharmaceutical ingredient, had adverse effects on Daphnia magna that were similar to its pharmaceutical action. In order to characterize the mode of action of propranolol in D. magna, which is suspected to be organ-specific pharmaceutical action or baseline toxicity, we performed time-series monitoring of behavior along with heart rate measurements and nuclear magnetic resonance (NMR) based metabolite profiling. Principle component analysis (PCA) and hierarchical clustering were used to categorize the mode of action of propranolol among 5 chemicals with different modes of action. The findings showed that the mode of action of propranolol in D. magna is organ-specific and vastly different from those of narcotics, even though metabolite regulation is similar between narcotic and non-narcotic candidates. The method applied in this study seems applicable to rapid characterization of the MOA of other cardiovascular pharmaceutical ingredients.

Knowledge of environmental risk factors for stroke and their role are limited. We performed a case-cohort study to evaluate the association between serum persistent organic pollutants (POPs) level and stroke risk.526 subcohort members and 111 stroke incidence cases were identified from the Korean Cancer Prevention Study-II. Serum levels of POPs were measured using gas chromatography/high-resolution mass spectrometry. The hazard ratios (HRs) for stroke (ischemic, hemorrhagic, and all stroke types) were estimated using the weighted Cox regression model. Age, sex, body mass index, smoking status, physical activity, family history of cardiovascular disease, and hypertension were adjusted in the weighted Cox regression model.After adjusting for potential confounding factors, increased risk for stroke was observed among participants with serum concentration of p,p'-DDE in the highest tertile compared to those in the lowest tertile (HR = 4.10, 95% CI: 1.58, 10.59). A similar association was estimated for PCB118 (HR = 2.33, 95% CI: 1.04, 5.22), PCB156 (HR = 3.42, 95% CI: 1.42, 8.23), and PCB138 (HR = 3.80, 95% CI: 1.48, 9.76). For TEQ, stroke was three times as likely to occur among subjects with TEQ in the highest tertile compared to those in the lowest tertile (HR = 3.12, 95% CI: 1.27, 7.65). PCBs were positively associated with ischemic stroke, but not with hemorrhagic stroke.Elevated serum POPs levels were associated with an increased risk of stroke, especially ischemic stroke.

Static environmental exposure assessment models based on material flow analysis (MFA) have previously been used to estimate flows of engineered nanomaterials (ENMs) to the environment. However, such models do not account for changes in the system behavior over time. Dynamic MFA used in this study includes the time-dependent development of the modelling system by considering accumulation of ENMs in stocks and the environment, and the dynamic release of ENMs from nano-products. In addition, this study also included regional variations in population, waste management systems, and environmental compartments, which subsequently influence the environmental release and concentrations of ENMs. We have estimated the flows and release concentrations of nano-SiO₂, nano-iron oxides, nano-CeO₂, nano-Al₂O₃, and quantum dots in the EU and six geographical sub-regions in Europe (Central Europe, Northern Europe, Southern Europe, Eastern Europe, South-eastern Europe, and Switzerland). The model predicts that a large amount of ENMs are accumulated in stocks (not considering further transformation). For example, in the EU 2040 Mt of nano-SiO₂ are stored in the in-use stock, 80,400 tonnes have been accumulated in sediments and 65,600 tonnes in natural and urban soil from 1990 to 2014. The magnitude of flows in waste management processes in different regions varies because of differences in waste handling. For example, concentrations in landfilled waste are lowest in South-eastern Europe due to dilution by the high amount of landfilled waste in the region. The flows predicted in this work can serve as improved input data for mechanistic environmental fate models and risk assessment studies compared to previous estimates using static models.

Plastic debris incidence in marine environment was already highlighted in the early 1970s. Over the last decade, microplastic pollution in the environment has received increasing attention and is now an emerging research area. Many studies have focused on quantifying microplastic abundance in the marine environment, while there are relatively few data on microplastic occurrence in freshwater environment. Recent studies have reported high concentrations of microplastics in lakes and rivers, although the understanding of several factors influencing source, transport and fate is still limited. This study compares different lakes and the common factors, which could influence the occurrence and distribution of microplastics. The three subalpine lakes monitored include Lake Maggiore, Iseo and Garda. The selected sampling transects reflect the hydrologic conditions, the morphometric characteristics of these lakes, and other factors influencing the release of plastics debris in lakes. Particles of microplastics (<5 mm) were found in all sampled surfaces. The particles collected were classified depending on their number, shape and composition. The shape distribution showed the dominating occurrence of fragments (73.7%). The chemical composition of all examined samples clearly shows dominating presence of polyethylene (45%), polystyrene (18%) and polypropylene (15%). The results provide significant relations among the different contribution of direct and diffuse sources to the quantity of microplastics, highlighting the importance of understanding the spatial distribution dynamics of microplastics within a lake system that acts as a sink and source of plastic particles.

Coastal areas are the transition zones between ocean and land where intracellular antibiotic resistance genes (iARGs) and extracellular antibiotic resistance genes (eARGs) could spread among marine organisms, and between humans and marine organisms. However, little attention has been paid to the combined research on iARGs and eARGs in marine environment. In this context, we collected water and sediment samples from the coastal areas of the Bohai Bay in China and performed molecular and chemical analyses. The results of quantitative real-time PCR (qPCR) showed that the relative abundance of eARGs was up to 4.3 ± 1.3 × 10−1 gene copies/16S rRNA copies in the water samples and 2.6 ± 0.3 × 10−3 gene copies/16S rRNA copies in the sediment samples. Also, the abundance of eARGs was significantly higher than that of iARGs. Furthermore, the average abundances of antibiotic resistance genes (ARGs, include iARGs and eARGs) were the highest in both the water and sediment samples from the estuaries. The results of liquid chromatography-mass spectrometry showed that the concentrations of antibiotics in estuaries and areas near the mariculture site were higher than that in the other sites. The class 1 integron gene (int1) and sul1 in the intracellular DNA were significantly correlated in the water samples. Moreover, significant correlation between int1 and sul2 in the extracellular DNA was also found in the sediment samples. The combination of sulfamerazine and tetracycline as well as the combination of sulfamethazine and dissolved oxygen can both explain the abundance of ARGs, implying the combined effects of multiple stresses on ARGs.

Nitrite is a common pollutant in water and is highly toxic to aquatic animals. To reveal the mechanism of salinity in attenuating nitrite toxicity to fish, we measured the physiological responses of juvenile Takifugu obscurus exposed to nitrite concentrations (0, 10, 20, 50, and 100 mg/L) under different salinity levels (0, 10, and 20 ppt) for 96 h. Salinity increased the survival rates of juvenile T. obscurus exposed to nitrite. Changes in key hematological parameters, antioxidant system, malondialdehyde, Na⁺/K⁺–ATPase, and HSP70 indicated that nitrite induced considerable damage to juveniles; salinity mitigated the harmful effects. This finding reflects similar changing trends in both antioxidants and their gene expressions among different tissues. We applied an overall index, an integrated biomarker response (IBR), that increased under high−nitrite condition but recovered to the normal levels under salinity treatment. Analysis of the selected detection indices and IBR values showed that the overall mitigating effect of salinity on nitrite toxicity seems to be at sub-cellular level and associated with complicated physiological responses.

Genetic and epigenetic changes were investigated in chronically irradiated Scots pine (Pinus sylvestris L.) populations from territories that were heavily contaminated by radionuclides as result of the Chernobyl Nuclear Power Plant accident. In comparison to the reference site, the genetic diversity revealed by electrophoretic mobility of AFLPs was found to be significantly higher at the radioactively contaminated areas. In addition, the genome of pine trees was significantly hypermethylated at 4 of the 7 affected sites.

The fast economic development of southwest China has resulted in significant increases in the concentrations of reactive nitrogen (Nr) in the atmosphere. In this study, an urban (Chengdu, CD), suburban (Shifang, SF) and agriculture (Yanting, YT) – dominated location in the Sichuan Province, southwest China, were selected to investigate the atmospheric composition of Nr, their concentrations and deposition rates. We measured Nr concentrations in precipitation (NH₄⁺, NO₃⁻ and organic N (DON)), the gas phase (NH₃ and NO₂), and the aerosol particles (PM₂.₅), and calculated their fluxes over a two year period (2014–2016). Total annual N deposition rates were 49.2, 44.7 and 19.8 kg N ha⁻¹ yr⁻¹ at CD, SF and YT, respectively. Ammonia concentrations were larger at the urban and suburban sites than the agricultural site (12.2, 14.9, and 4.9 μg N m⁻³ at CD, SF and YT, respectively). This is consistent with the multitude of larger sources of NH₃, including city garbage, livestock and traffic, in the urban and suburban areas. Monthly NO₂ concentrations were lower in warmer compared to the colder months, but seasonal differences were insignificant. Daily PM₂.₅ concentrations ranged from 7.7 to 236.0, 5.0–210.4 and 4.2–128.4 μg m⁻³ at CD, SF and YT, respectively, and showed significant correlations with fine particulate NH₄⁺ and NO₃⁻ concentrations. Ratios of reduced to oxidized N were in the range of 1.6–2.7. This implies that the control of reduced Nr especially in urban environments is needed to improve local air quality.

Pesticides, in particular insecticides, can be very beneficial but have also been found to have harmful side effects on non-target insects. Butterflies play an important role in ecosystems, are well monitored and are recognised as good indicators of environmental health. The amount of information already known about butterfly ecology and the increased availability of genomes make them a very valuable model for the study of non-target effects of pesticide usage. The effects of pesticides are not simply linear, but complex through their interactions with a large variety of biotic and abiotic factors. Furthermore, these effects manifest themselves at a variety of levels, from the molecular to metapopulation level. Research should therefore aim to dissect these complex effects at a number of levels, but as we discuss in this review, this is seldom if ever done in butterflies. We suggest that in order dissect the complex effects of pesticides on butterflies we need to integrate detailed molecular studies, including characterising sequence variability of relevant target genes, with more classical evolutionary ecology; from direct toxicity tests on individual larvae in the laboratory to field studies that consider the potentiation of pesticides by ecologically relevant environmental biotic and abiotic stressors. Such integration would better inform population-level responses across broad geographical scales and provide more in-depth information about the non-target impacts of pesticides.