Ciprofloxacin (CIP) is a broad-spectrum antibiotic found within μg/L concentration range in the aquatic environment. It is a known contributor of umuC induction in hospital wastewater samples. CIP can undergo photolysis to result in many transformation products (TPs) of mostly unknown toxicity. The aims of this study were to determine the genotoxicity of the UV mixtures and to understand the possible genotoxic role of the stable TPs. As such, CIP and its UV-irradiated mixtures were investigated in a battery of genotoxicity and cytotoxicity in vitro assays. The combination index (CI) analysis of residual CIP in the irradiated mixtures was performed for the umu assay. Further, Quantitative Structure–Activity Relationships (QSARs) predicted selected genotoxicity endpoints of the identified TPs. CIP achieved primary elimination after 128 min of irradiation but was not completely mineralized. Nine photo-TPs were identified. The irradiated mixtures were neither mutagenic in the Ames test nor genotoxic in the in vitro micronucleus (MN) test. Like CIP, the irradiated mixtures were umuC inducing. The CI analysis revealed that the irradiated mixtures and the corresponding CIP concentration in the mixtures shared similar umuC potentials. QSAR predictions suggested that the TPs may be capable of inducing chromosome aberration, MN in vivo, bacterial mutation and mammalian mutation. However, the experimental testing for a few genotoxic endpoints did not show significant genotoxic activity for the TPs present as a component of the whole mixture analysis and therefore, further genotoxic endpoints may need to be investigated to fully confirm this.

Nitrogen (N) deposition impacts natural and semi-natural ecosystems globally. The responses of vegetation to N deposition may, however, differ strongly between habitats and may be mediated by the form of N. Although much attention has been focused on the impact of total N deposition, the effects of reduced and oxidised N, independent of the total N deposition, have received less attention. In this paper, we present new analyses of national monitoring data in the UK to provide an extensive evaluation of whether there are differences in the effects of reduced and oxidised N deposition across eight habitat types (acid, calcareous and mesotrophic grasslands, upland and lowland heaths, bogs and mires, base-rich mires, woodlands). We analysed data from 6860 plots in the British Countryside Survey 2007 for effects of total N deposition and N form on species richness, Ellenberg N values and grass:forb ratio. Our results provide clear evidence that N deposition affects species richness in all habitats except base-rich mires, after factoring out correlated explanatory variables (climate and sulphur deposition). In addition, the form of N in deposition appears important for the biodiversity of grasslands and woodlands but not mires and heaths. Ellenberg N increased more in relation to NHx deposition than NOy deposition in all but one habitat type. Relationships between species richness and N form were habitat-specific: acid and mesotrophic grasslands appear more sensitive to NHx deposition while calcareous grasslands and woodlands appeared more responsive to NOy deposition. These relationships are likely driven by the preferences of the component plant species for oxidised or reduced forms of N, rather than by soil acidification.

Recently it became known that Volkswagen Group has been cheating with emission tests for diesel engines over the last six years, resulting in on-road emissions vastly exceeding legal standards for nitrogen oxides in Europe and the United States. Here, we provide an estimate of the public health consequences caused by this fraud. From 2009 to 2015, approximately nine million fraudulent Volkswagen cars, as sold in Europe and the US, emitted a cumulative amount of 526 ktonnes of nitrogen oxides more than was legally allowed. These fraudulent emissions are associated with 45 thousand disability-adjusted life years (DALYs) and a value of life lost of at least 39 billion US dollars, which is approximately 5.3 times larger than the 7.3 billion US dollars that Volkswagen Group has set aside to cover worldwide costs related to the diesel emissions scandal.

Information on the biological responses of polyploid animals towards environmental contaminants is scarce. This study aimed to compare reproductive axis-related gene expressions in the brain, plasma biochemical responses, and the liver and gill histopathological alterations in diploid and triploid full-sibling juvenile African catfish (Clarias gariepinus). Fish were exposed for 96 h to one of the two waterborne phenanthrene (Phe) concentrations [mean measured (SD): 6.2 (2.4) and 76 (4.2) μg/L]. In triploids, exposure to 76 μg/L Phe increased mRNA level of fushi tarazu-factor 1 (ftz-f1). Expression of tryptophan hydroxylase2 (tph2) was also elevated in both ploidies following the exposure to 76 μg/L Phe compared to the solvent control. In triploids, 76 μg/L Phe increased plasma alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) levels compared to the other Phe-exposed group. It also elevated lactate and glucose contents relative to the other groups. In diploids, however, biochemical biomarkers did not change. Phenanthrene exposures elevated glycogen contents and the prevalence of histopathological lesions in the liver and gills of both ploidies. This study showed substantial differences between diploids and triploids on biochemical and molecular biomarker responses, but similar histopathological alterations following acute Phe exposures.

Rice is one of the major pathways of arsenic (As) exposure in human food chain, threatening over half of the global population. Greenhouse pot experiments were conducted to examine the effects of Si application on iron (Fe) plaque formation, As uptake and rice grain As speciation in indica and hybrid rice genotypes with different radial oxygen loss (ROL) ability. The results demonstrated that Si significantly increased root and grain biomass. Indica genotypes with higher ROL induced greater Fe plaque formation, compared to hybrid genotypes and sequestered more As in Fe plaque. Silicon applications significantly increased Fe concentrations in iron plaque of different genotypes, but it decreased As concentrations in the roots, straws and husks by 28–35%, 15–35% and 32–57% respectively. In addition, it significantly reduced DMA accumulation in rice grains but not inorganic As accumulation. Rice of indica genotypes with higher ROL accumulated lower concentrations of inorganic As in grains than hybrid genotypes with lower ROL.

Bacterial communities in sediments of human-impacted rivers are exposed to multiple anthropogenic contaminants and eventually lead to biodiversity lost and ecological functions disable. Nanfei River of Anhui province has been contaminated by pollutants from industrial and/or agricultural sources. This study was conducted to investigate the structure of in situ sediment bacterial communities in Nanfei River and to examine the correlation between the different taxonomic components and contaminant concentrations. The bacterial communities were dominated by Proteobacteria, Bacteroidetes and Chloroflexi. Both the profiles of environmental predictors and the composition of microbial communities differed among agriculture, industrial and confluence regions. There were significant associations between bacterial community phylogenies and the measured contaminants in the sediments. Nutrients (TN and TP) and two metals (Cd and Zn) were negatively correlated with the essential “core” of the bacterial interaction network (Betaproteobacteria and Deltaproteobacteria). Metals (Fe, Ni and Zn) and nutrients (TN and TP) had higher impact on bacterial community compositions than PAHs, OPs and PRTs according to the correlation and network analyses. Furthermore, several sensitive candidate genera were identified as potential bioindicators to monitor key contaminants by species contaminant correlation analysis. Overall, in situ bacterial communities could provide a useful tool for monitoring and assessing ecological stressors in freshwater sediments.

Periphyton have been widely applied in aquaculture systems, however, little information is available on how periphyton respond to such high nutrient levels in water. Thus, changes in the morphological characteristics, community structure, and metabolic function of periphyton under high eutrophic waters were evaluated. The results indicated that the morphology of periphyton was affected by increasing the nutrient concentration of water, which shifted the micromorphology of periphyton from spheriform to filamentous. The periphyton under higher water nutrient levels were able to utilize more carbon source types. Additionally, higher water nutrient levels increased the bacterial and protozoal proportions in periphyton. This study fills the gap in knowledge about the responses of periphytic communities to extremely eutrophic waters. It provides valuable information on the full understanding of the periphyton-nutrient relationship in aquaculture systems, which is beneficial for regulating the microbial species or communities in periphyton by manipulating the nutrient levels in water.

In order to better understand the exposure of aquatic systems to halogenated flame retardant contaminants, the present study investigated a variety of legacy and emerging flame retardants in common carp and largemouth bass collected from 58 stations across Illinois (United States). The data revealed that polybrominated diphenyl ethers (PBDEs) generally dominated the flame retardant residues in Illinois fish. Concentrations of ΣPBDEs (including all detectable PBDE congeners) ranged from 24.7 to 8270 ng/g lipid weight (median: 135 ng/g lw) in common carp and 15–3870 ng/g lw (median: 360 ng/g lw) in largemouth bass. In addition to PBDEs, Dechlorane analogues (i.e. Dec-603, Dec-604, and Chlordane Plus) were also frequently detected. Median concentrations of ΣDechloranes (including all detected Dechlorane analogues) were 34.4 and 23.3 ng/g lw in common carp and largemouth bass, respectively. Other emerging flame retardants, including tetrabromo-o-chlorotoluene (TBCT), hexabromobenzene (HBBZ), 2-ethylhexyltetrabromobenzoate (EH-TBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP), were also detected in 40–78% of the fish at the monitored stations. Spatial analysis revealed significantly greater PBDE concentrations in fish living in impaired urban streams and lakes compared to those from the impaired agricultural and unimpaired agricultural/urban waters, demonstrating a significant urban influence on PBDE contamination. Future studies and environmental monitoring are recommended to focus on temporal trends of PBDEs and alternative flame retardants, as well as human exposure risks via edible fishes, in the identified Areas of Concern within Illinois.

The presence of polycyclic aromatic hydrocarbons (PAHs) in biochars hinders their environmental use. The aim of this study was to determine the freely dissolved (Cfree) PAH content in soil amended with biochar in a long-term (851 days) field experiment. Biochar was added to the soil at a rate of 30 and 45 t/ha. The addition of biochar to the soil resulted in a decrease in Σ13 Cfree PAHs by 25 and 22%, in the soil with the addition of biochar at the rate of 30 and 45 t/ha, respectively. As far as individual PAHs are concerned, in most cases a reduction in Cfree was also observed (from 3.6 to 66%, depending on the biochar rate). During the first 105 days of the experiment, the content of Σ13 Cfree in the biochar-amended soil significantly decreased by 26% (30 t/ha) and 36% (45 t/ha). After this period of time until the end of the experiment, no significant changes in Cfree were observed, regardless of the biochar rate. However, the behavior of individual PAH groups differed depending on the number of rings and experimental treatment. Ultimately, after 851 days of the experiment the content of Σ13 Cfree PAHs was lower by 29% (30 t/ha) and 35% (45 t/ha) compared to the beginning of the study as well as lower by 40% (30 t/ha) and 42% (45 t/ha) than in the control soil. The log KTOC coefficients calculated for the biochar-amended soils were higher immediately after adding biochar and subsequently they gradually decreased, indicating the reduced strength of the interaction between biochar and the studied PAHs. The obtained results show that the addition of biochar to soil does not create a risk in terms of the content of Cfree PAHs.

Pb tolerant mechanisms, plant physiological response and Pb sub-cellular localization in the root cells of Iris halophila were studied in sand culture and the Pb mine tailings. Results showed that the activities of superoxide dismutase (SOD) and peroxidase (POD) in the underground parts and the activity of catalase (CAT) in the aboveground and underground parts increased as Pb level was enhanced. Glutathione (GSH) and ascorbic acid (AsA) contents increased by Pb treatments. Pb deposits were found in the middle cell walls or along the inner side of epibiotic protoplasm of some cells which accumulated a large quantity of Pb and died. The dry weights (DWs) of aboveground parts under all Pb tailings treatments decreased insignificantly, while the DW of the underground parts growing in the pure Pb tailings decreased significantly. Pb, Cu, Cd, and Zn contents increased significantly as the levels of Pb tailings were enhanced and Pb contents in the aboveground and underground parts reached 64.75 and 751.75 μg/g DW, respectively, at pure Pb tailings treatment. The results indicated that I. halophila is a promising plant in the phytoremediation of Pb contaminated environment. Some antioxidant enzymes, antioxidants and compartmentalization of Pb were played major roles in Pb tolerance of I. halophila.