The main objective of the current study was to estimate the potential environmental risks associated with human consumption of antimicrobials in Greece. Consumption data was collected for the 24 most often used antimicrobials for the years 2008–2010, and their predicted environmental concentrations (PECs) in raw and treated wastewater were calculated using mass balances and literature data on human excretion and elimination efficiency during wastewater treatment. The ecotoxicological risk was estimated by calculating the ratio of PEC to predicted no-effect concentration (PNEC) for three categories of aquatic organisms (algae, daphnids, and fish). PNEC values were calculated based on experimental ecotoxicity data and data originated from the Ecological Structure Activity Relationship (ECOSAR). PEC values in raw sewage ranged between 0.02 μg L⁻¹(erythromycin) and 27 μg L⁻¹(amoxicillin), while in treated wastewater, the highest concentration was predicted for cefuroxime axetil (6.6 μg L⁻¹). Based on acute toxicity data for algae, risk quotient (RQ) values higher than 1 were obtained for 7 out of the 24 target antimicrobials in raw and treated wastewater, while no significant risk was estimated for daphnids and fish. Regarding the possible risk due to the chronic toxicity of antimicrobials, RQ values higher than 80 were obtained for amoxicillin and clarithromycin in algae. The use of baseline toxicity data from ECOSAR showed that the environmental risk from exposure to mixtures of antimicrobials was low for all three aquatic species. However, further studies on toxicity of mixtures should be performed as calculation of toxicity ratio (TR) values showed that 90 % of the target antimicrobials seem to exhibit a specific mode of toxic action when present in mixtures rather than baseline toxicity. As a result, an underestimation of toxicity based on the ECOSAR model is possible for the mixture of target antimicrobials. For Greek rivers where low (dilution factor, D < 10) and medium (D = 10–100) dilution of wastewater occurs, moderate to high risk is expected due to the existence of individual antimicrobials such as amoxicillin, clarithromycin, ciprofloxacin, azithromycin, erythromycin, and levofloxacin in discharged treated wastewater.

A greenhouse experiment was conducted to investigate the effects of zucchini (Cucurbita pepo L.), inoculated with the arbuscular mycorrhizal (AM) species Acaulospora laevis, Glomus caledonium, and Glomus mosseae, on the soil bacterial community responsible for Aroclor 1242 dissipation. The dissipation rates of Aroclor 1242 and soil bacteria abundance were much higher with the A. laevis and G. mosseae treatments compared to the non-mycorrhizal control. The biphenyl dioxygenase (bphA) and Rhodococcus-like 2,3-dihydroxybiphenyl dioxygenase (bphC) genes were more abundant in AM inoculated soils, suggesting that the bphA and Rhodococcus-like bphC pathways play an important role in Aroclor 1242 dissipation in the mycorrhizosphere. The soil bacterial communities were dominated by classes Betaproteobacteria and Actinobacteria, while the relative proportion of Actinobacteria was significantly (F = 2.288, P < 0.05) correlated with the PCB congener profile in bulk soil. Our results showed that AM fungi could enhance PCB dissipation by stimulating bph gene abundance and the growth of specific bacterial groups.

Treatment and disposal of fly ash in China are becoming increasingly difficult, since its production has steadily risen and its features are uncertain. The excess pollutant components of fly ash are the key factor affecting its treatment and resource utilization. In this study, fly ash samples collected from a power plant with circulating fluidized incinerators of municipal solid waste (MSW) located in Shandong Province (eastern China) were studied. The results showed that there were no obvious seasonal differences in properties of fly ash. The content of total salt, Zn, and pH exceeded the national standards and low-ring polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (Fs) were the main organic components of fly ash for this power plant, which posed great threats to the surrounding environment. The amount of Zn of fly ash was higher than other heavy metals, which should be due to alkaline batteries of MSW. The leachate of fly ash had low concentrations of heavy metals and the main soluble components were sulfates and chlorides. The major mineral crystals of fly ash were SiO₂, CaSO₄, and Fe₂O₃. The main organic pollutants were low-ring PAHs, polychlorinated PCDDs, and low-chlorinated PCDFs, and concentrations were lower than the limiting values of the national regulations. Additionally, the distribution of PCDD/Fs had either a positive or a negative linear correlation with fly ash and flue gas, which was associated with the chlorinated degree of PCDD/Fs. The analysis was conducted to fully understand the properties of fly ash and to take appropriate methods for further comprehensive utilization.

Water is an essential factor for maintaining the vital functions of living beings. Nickel is the 24th most abundant element on Earth; it is a heavy metal that is genotoxic and mutagenic in its chloride form. Due to industrial use, its concentration in surface sediments increased considerably. Fish develop characteristics that make them excellent experimental models for studying aquatic toxicology. They are particularly useful because they can alert of the potential danger of chemical substances or environmental pollution. Due to water quality impairment and because there are few published studies that relate nickel to tissue alteration, this study aimed to examine the consequences of nickel in an aquatic environment. For this analysis, individuals of Oreochromis niloticus were exposed for 96 h to three different concentrations of nickel dissolved in water according to the standard established by Brazilian law and compared them to a control group. After exposure, the gills were analyzed using X-ray microanalysis, ultramorphology, and histological and histochemical analysis. The results demonstrated that all the concentrations used in the experiment altered the histophysiology of the individuals exposed. In conclusion, the nickel presents a toxic potential to fish, even at the lowest concentration tested, which is equivalent to half of the concentration allowed by law. The CONAMA resolution should be revised for this parameter because of the interference of this metal in the histophysiology of the tested organism.

In recent decades, China’s agriculture has been experiencing flourishing growth accompanied by rising pesticide consumption, fertilizer consumption, energy consumption, etc. and increasing CO₂emissions. Analyzing the driving forces of agricultural CO₂emissions is key requirements for low-carbon agricultural policy formulation and decomposition analysis is widely used for this purpose. This study estimates the agricultural CO₂emissions in China from 1994 to 2011 and applies the Logarithmic Mean Divisia Index (LMDI) as the decomposition technique. Change in agricultural CO₂emissions is decomposed from 1994 to 2011 and includes a measure of the effect of agricultural subsidy. Results illustrate that economic development acts to increase CO₂emissions significantly. Agricultural subsidy acts to reduce CO₂emissions effectively and has increased in recent years. Policy is needed to significantly optimize agricultural subsidy structure and change agricultural development pathway, if China’s low-carbon agriculture target is to be achieved. This requires not only decreasing pesticide consumption, fertilizer consumption, energy consumption, etc. but also transformation of China’s agricultural development path for optimal outcomes.

Understanding the influence of arbuscular mycorrhizal (AM) fungi on the expressions of the dominant plant-related genes under heavy metal (HM) stress is important for developing strategies to reclaim polluted sites. In this study, we cloned full-length cDNAs of phytochelatin synthase gene (PCS1) and Actin of Sophora viciifolia Hance., a predominant plant in Qiandongshan lead and zinc mine, by rapid amplification of cDNA ends. Consequently, we studied the response of SvPCS1 to Funneliformis mosseae inoculation under lead stress (0, 50, and 200 μM Pb(NO₃)₂) at different durations (1, 3, and 7 days) using quantitative reverse-transcription polymerase chain-reaction (qRT-PCR) technique. The Pb concentrations and chlorophyll fluorescence parameters were also measured to assay Pb toxicity to Sophora viciifolia. We found that Pb concentrations in roots increased with increasing Pb application and the durations; the F ᵥ /F ₘ , F ᵥ /F ₒ , qP, and Y(II) decreased; NPQ rose with increasing Pb concentrations; mycorrhizal symbiosis alleviated the Pb toxicity to plants; and SvPCS1 was constitutively expressed in the roots. It was also found that F. mosseae inoculation could promote the expression of SvPCS1 with the concentration ≤200 μM at the exposure time shorter than 7 days.

Trichloroacetic acid (TCA), a common water disinfection byproduct and a persistent metabolite of trichloroethylene (TCE), has been examined for its genotoxic potential in human lymphocytes. Chromosomal aberration (CA) and cytokinesis-block micronucleus (CBMN) assay were employed to assess the toxicity of TCA. Lymphocytes obtained from three healthy donors were exposed to 25, 50, and 100 μg/ml concentration of TCA separately. TCA exposure resulted in chromosomal anomalies and the formation of micronuclei in lymphocytes. Chromosome analysis revealed the dose-dependent and significant induction of CA. Chromatid break/chromosome break, fragments, and chromatid exchanges were commonly observed. Exposure of higher concentration (50 and 100 μg/ml) significantly inhibited mitotic index. Data obtained with CBMN assay indicated that the induction of micronucleus (MN) formation was greater than that of CA. At 25 μg/ml, TCA induced significant frequencies of MN as compared to control cells. Significant induction of MN at the lowest concentration indicates TCA may also interact with mitotic spindles. Lower percentage of CA and MN at 100 μg/ml as compared to 50 μg/ml indicates occurrence of severe cytotoxicity on exposure of 100 μg/ml TCA in lymphocytes. Collectively, results of both cytogenetic assays indicate that exposure of TCA can induce significant genotoxic and cytotoxic effects.

Soils in urban areas are subjected to compaction with accelerating urbanization. The effects of anthropogenic compaction on urban soil denitrification are largely unknown. We conducted a study on an urban park soil to investigate how compaction impacts denitrification. By using¹⁵N labeling method and acetylene inhibition technique, we performed three coherent incubation experiments to quantify denitrification in compacted soil under both aerobic and anaerobic conditions. Uncompacted soil was set as the control treatment. When monitoring soil incubation without extra substrate, higher nitrous oxide (N₂O) flux and denitrification enzyme activity were observed in the compacted soil than in the uncompacted soil. In aerobic incubation with the addition of K¹⁵NO₃, N₂O production in the compacted soil reached 10.11 ng N h⁻¹ g⁻¹as compared to 0.02 ng N h⁻¹ g⁻¹in the uncompacted soil. Denitrification contributed 96 % of the emitted N₂O in the compacted soil and 36 % of the emitted N₂O in the uncompacted soil; total denitrification rate was higher in the compacted soil (up to 79.35 ng N h⁻¹ g⁻¹) than in the uncompacted soil (0.11 ng N h⁻¹ g⁻¹). Under anaerobic incubation with the addition of K¹⁵NO₃, no statistical difference in total N losses and¹⁵N-(N₂O+N₂) flux between the uncompacted soil and the compacted soil was detected. Compaction promoted soil denitrification and may impact urban N biogeochemical cycling.

In the salt marshes of the joint estuary of Tinto and Odiel rivers (SW Spain), one of the most polluted areas by heavy metals in the world, Spartina densiflora grows on sediments with high concentrations of heavy metals. Furthermore, this species has shown to be useful for phytoremediation. The total bacterial population of the rhizosphere of S. densiflora grown in two estuaries with different levels of metal contamination was analyzed by PCR denaturing gradient gel electrophoresis. Results suggested that soil contamination influences bacterial population in a greater extent than the presence of the plant. Twenty-two different cultivable bacterial strains were isolated from the rhizosphere of S. densiflora grown in the Tinto river estuary. Seventy percent of the strains showed one or more plant growth-promoting (PGP) properties, including phosphate solubilization and siderophores or indolacetic acid production, besides a high resistance towards Cu. A bacterial consortium with PGP properties and very high multiresistance to heavy metals, composed by Aeromonas aquariorum SDT13, Pseudomonas composti SDT3, and Bacillus sp. SDT14, was selected for further experiments. This consortium was able to two-fold increase seed germination and to protect seeds against fungal contamination, suggesting that it could facilitate the establishment of the plant in polluted estuaries.

Rare earth element accumulation in the soil and elevated ultraviolet (UV)-B radiation (280–315 nm) are important environmental issues worldwide. To date, there have been no reports concerning the combined effects of lanthanum (La)(III) and elevated UV-B radiation on plant roots in regions where the two issues occur simultaneously. Here, the combined effects of La(III) and elevated UV-B radiation on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean (Glycine max L.) seedlings were investigated. A 0.08 mmol L⁻¹La(III) treatment improved the root growth and biomass of soybean seedlings, while ion absorption, activities, and membrane permeability were obviously unchanged; a combined treatment with 0.08 mmol L⁻¹La(III) and elevated UV-B radiation (2.63/6.17 kJ m⁻² day⁻¹) exerted deleterious effects on the investigated indices. The deleterious effects were aggravated in the other combined treatments and were stronger than those of treatments with La(III) or elevated UV-B radiation alone. The combined treatment with 0.24/1.20 mmol L⁻¹La(III) and elevated UV-B radiation exerted synergistically deleterious effects on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean seedlings. In addition, the deleterious effects of the combined treatment on the root growth were due to the inhibition of ion absorption induced by the changes in the root activity and membrane permeability.