Imidacloprid (IMI) is a commonly used pesticide against aphids and accumulates in plant parts, maximum in leaves. Present study was conducted to check the efficiency of seed pre-soaking with 24-epibrassinolide (24-EBL) for reduction of this pesticide in the leaves of Brassica juncea L. plants raised from 24-EBL pre-soaked seeds and grown in soils supplemented with IMI. Leaves were analyzed for IMI residues using gas chromatography-mass spectrometry (GC-MS). Activities of guaiacol peroxidase (POD), glutathione reductase (GR), and glutathione S-transferase (GST), and glutathione (GSH) content were determined by spectrophotometry. Soil containing 350 mg IMI/kilogram soil resulted in 88.66 μg/g fresh weight (FW) of IMI residue in the leaves, which was maximum decrease to 35.31 μg/g FW (60.17 %), when seeds were pre-soaked in 100 nM 24-EBL. In this treatment (350 mg IMI/kilogram soil + 100 nM 24-EBL), GSH content, GR, POD, and GST activities were increased by 42.30, 34.5, 20.5, and 13.4 %, respectively, as compared to plants grown in soils amended with 350 mg IMI/kilogram soil.

The high chroma of cellulosic ethanol production wastewater poses a serious environmental concern; however, color-causing compounds are still not fully clear. The characteristics of the color compounds and decolorization of biologically treated effluent by electro-catalytic oxidation were investigated in this study. Excitation-emission matrix (EEM), fourier transform infrared spectrometer (FTIR), UV-Vis spectra, and ultrafiltration (UF) fractionation were used to analyze color compounds. High chroma of wastewater largely comes from humic materials, which exhibited great fluorescence proportion (67.1 %) in the biologically treated effluent. Additionally, the color compounds were mainly distributed in the molecular weight fractions with 3–10 and 10–30 kDa, which contributed 53.5 and 34.6 % of the wastewater color, respectively. Further decolorization of biologically treated effluent by electro-catalytic oxidation was investigated, and 98.3 % of color removal accompanied with 97.3 % reduction of humic acid-like matter was achieved after 180 min. The results presented herein will facilitate the development of a well decolorization for cellulosic ethanol production wastewater and better understanding of the biological fermentation.

Degradation of aqueous solution of bisphenol A (BPA) has been investigated through non-catalytic and catalytic ozonation treatments conducted in a semi-batch reactor. Non-catalytic ozonation resulted in complete degradation of aqueous BPA in less than 3 min but did not completely convert the reaction intermediates of BPA ozonation into CO₂ and H₂O. The main goal of this study was to find an effective heterogeneous catalyst to increase the extent of BPA mineralization at different pH conditions. In this way, the most promising catalyst carrier was γ-Al₂O₃; at pH = 8.0, 68 % of total organic carbon (TOC) was removed in the period of 75 min, out of which 42 % was attributed to mineralization. Finally, 3.0 wt.% Ru/γ-Al₂O₃ catalyst exhibited over 82 % of TOC removal after 240 min of ozonation at pH = 5.9, of which 56 % was mineralized.

In this study, a bacterial strain able to use sulcotrione, a β-triketone herbicide, as sole source of carbon and energy was isolated from soil samples previously treated with this herbicide. Phylogenetic study based on16S rRNA gene sequence showed that the isolate has 100 % of similarity with several Bradyrhizobium and was accordingly designated as Bradyrhizobium sp. SR1. Plasmid profiling revealed the presence of a large plasmid (>50 kb) in SR1 not cured under nonselective conditions. Its transfer to Escherichia coli by electroporation failed to induce β-triketone degrading capacity, suggesting that degrading genes possibly located on this plasmid cannot be expressed in E. coli or that they are not plasmid borne. The evaluation of the SR1 ability to degrade various synthetic (mesotrione and tembotrione) and natural (leptospermone) triketones showed that this strain was also able to degrade mesotrione. Although SR1 was able to entirely dissipate both herbicides, degradation rate of sulcotrione was ten times higher than that of mesotrione, showing a greater affinity of degrading-enzyme system to sulcotrione. Degradation pathway of sulcotrione involved the formation of 2-chloro-4-mesylbenzoic acid (CMBA), previously identified in sulcotrione degradation, and of a new metabolite identified as hydroxy-sulcotrione. Mesotrione degradation pathway leads to the accumulation of 4-methylsulfonyl-2-nitrobenzoic acid (MNBA) and 2-amino-4 methylsulfonylbenzoic acid (AMBA), two well-known metabolites of this herbicide. Along with the dissipation of β-triketones, one could observe the decrease in 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibition, indicating that toxicity was due to parent molecules, and not to the formed metabolites. This is the first report of the isolation of bacterial strain able to transform two β-triketones.

Several studies provide evidence of calcium (Ca)-limited reproduction in birds. A Ca-supplementation experiment was carried out in 2014 in a Ca-poor area associated with metal pollution in SW Finland. We aimed to evaluate the relationship between Ca availability and heavy metal exposure in free-living passerines, and to compare Ca levels in plasma and feces and the effects of Ca supplementation and metals on breeding, nestling growth, and plasma biochemistry in great tits and pied flycatchers. Although the Ca supplement was used by parents, in general the treatment had limited effects on growth and biochemistry, suggesting that parents are capable of finding sufficient Ca-rich foods to allow nestlings to grow properly. Snail shells were an abundant Ca source in the moderately polluted zone for pied flycatcher, and great tits likely combines the intake of snail shells and other anthropogenic Ca-rich items. Great tits had higher Ca concentrations in feces and plasma than pied flycatcher nestlings, suggesting that they need and sustain higher Ca levels and seem to be more opportunistic in search for Ca than pied flycatcher, since they consumed more of the supplemented Ca. Negative effects of pollution in nestling size and fledgling number were found in great tit. This species may suffer especially from the lower food quality and quantity in the polluted area. The pied flycatcher seems to be adapted to low Ca availability and they can successfully breed when metal concentrations are not too high. Our results show that great tits and pied flycatchers may employ different strategies in response to low Ca availability.

In the present study, a two-hybrid yeast bioassay and a T-screen were used to screen for the thyroid receptor (TR)-disrupting activity of select metallic compounds (CdCl₂, ZnCl₂, HgCl₂, CuSO₄, MnSO₄, and MgSO₄). The results reveal that none of the tested metallic compounds showed TR-agonistic activity, whereas ZnCl₂, HgCl₂, and CdCl₂ demonstrated TR antagonism. For the yeast assay, the dose–response relationship of these metallic compounds was established, and the concentrations producing 20 % of the maximum effect of ZnCl₂, HgCl₂, and CdCl₂ were 9.1 × 10⁻⁵, 3.2 × 10⁻⁶, and 1.2 × 10⁻⁶ mol/L, respectively. The T-screen also supported the finding that ZnCl₂, HgCl₂, and CdCl₂ decreased the cell proliferation at concentrations ranging from 10⁻⁶ to 10⁻⁴ mol/L. Furthermore, the thyroid-disrupting activity of metallic compounds in environmental water samples collected from the Guanting Reservoir, Beijing, China was evaluated. Solid-phase extraction was used to separate the organic extracts, and a modified two-hybrid yeast bioassay revealed that the metallic compounds in the water samples could affect thyroid hormone-induced signaling by decreasing the binding of the thyroid hormone. The addition of ethylenediaminetetraacetic acid (30 mg/L) could eliminate the effects. Thus, the cause(s) of the thyroid toxicity in the water samples appeared to be partly related to the metallic compounds.

To investigate the chemical characteristics of organic acids and to identify their source, cloud water and rainwater samples were collected at Mount Lu, a mountain site located in the acid rain-affected area of south China, from August to September of 2011 and March to May of 2012. The volume-weighted mean (VWM) concentration of organic acids in cloud water was 38.42 μeq/L, ranging from 7.45 to 111.46 μeq/L, contributing to 2.50 % of acidity. In rainwater samples, organic acid concentrations varied from 12.39 to 68.97 μeq/L (VWM of 33.39 μeq/L). Organic acids contributed significant acidity to rainwater, with a value of 17.66 %. Formic acid, acetic acid, and oxalic acid were the most common organic acids in both cloud water and rainwater. Organic acids had an obviously higher concentration in summer than in spring in cloud water, whereas there was much less discrimination in rainwater between the two seasons. The contribution of organic acids to acidity was lower during summer than during spring in both cloud water (2.20 % in summer vs 2.83 % in spring) and rainwater (12.24 % in summer vs 19.89 % in spring). The formic-to-acetic acid ratio (F/A) showed that organic acids were dominated by primary emissions in 71.31 % of the cloud water samples and whole rainwater samples. Positive matrix factorization (PMF) analysis determined four factors as the sources of organic acids in cloud water, including biogenic emissions (61.8 %), anthropogenic emissions (15.28 %), marine emissions (15.07 %) and soil emissions (7.85 %). The findings from this study imply an indispensable role of organic acids in wet deposition, but organic acids may have a limited capacity to increase ecological risks in local environments.

We evaluated the utility of chironomid and lamprey larval responses in ecotoxicity assessment of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F)-, polychlorinated biphenyls (PCB)- and mercury (Hg)-contaminated river sediments. Sediment samples were collected from the River Kymijoki with a known industrial pollution gradient. Sediment for the controls and lamprey larvae were obtained from an uncontaminated river nearby. Contamination levels were verified with sediment and tissue PCDD/F, PCB and Hg analyses. Behaviour of sediment-exposed chironomid and lamprey larvae were measured with Multispecies Freshwater Biomonitor© utilizing quadrupole impedance conversion technique. In addition, mortality, growth and head capsule deformity incidence of chironomids were used as ecotoxicity indicators. WHOPCDD/F₊PCB-TEQ in the R. Kymijoki sediments ranged from the highest upstream 22.36 ng g⁻¹ dw to the lowest 1.50 ng g⁻¹ near the river mouth. The sum of PCDD/Fs and PCBs correlated strongly with Hg sediment concentrations, which ranged from <0.01 to 1.15 μg g⁻¹. Lamprey tissue concentrations of PCDD/Fs were two orders and PCBs one order of magnitude higher in the R. Kymijoki compared to the reference. Chironomid growth decreased in contaminated sediments and was negatively related to sediment ∑PCDD/Fs, WHOPCDD/F₊PCB-TEQ and Hg. There were no significant differences in larval mortality or chironomid mentum deformity incidence between the sediment exposures. The distinct behavioural patterns of both species indicate overall applicability of behavioural MFB measurements of these species in sediment toxicity bioassays. Chironomids spent less and lampreys more time in locomotion in the most contaminated sediment compared to the reference, albeit statistically significant differences were not detected. Lamprey larvae had also a greater activity range in some of the contaminated sediments than in the reference. High pollutant levels in lamprey indicate risks for biomagnification in the food webs, with potential health risks to humans consuming fish.

The influences of Cu²⁺ and Fe²⁺ on the photodegradation of soil-incorporated chlorpyrifos were investigated in the present study. The soil samples spiked with chlorpyrifos and selected metal ions were irradiated with UV light for different intervals of time and analyzed by HPLC. The unsterile and sterile control soil samples amended with pesticides and selected metals were incubated in the dark at 25 °C for the same time intervals. The results of the study evidenced that photodegradation of chlorpyrifos followed the first-order kinetics. The dissipation t₀.₅ of chlorpyrifos was found to decrease from 41 to 20 days under UV irradiation. The rate of chlorpyrifos photodegradation was increased in the presence of both metals, i.e., Cu²⁺ and Fe²⁺. Thus, initially observed t₀.₅ of 19.8 days was decreased to 4.39 days in the case of Cu⁺² and 19.25 days for Fe⁺². Copper was found to increase the rate of photodegradation by 4.5 orders of magnitude while the microbial degradation of chlorpyrifos was increased only twofold. The microbial degradation of chlorpyrifos was only negligibly affected by Fe²⁺ amendment. The studied trace metals also affected the abiotic degradation of the pesticide in the order Cu²⁺ > Fe²⁺.

A culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (SRpf) was used to enhance the biological nutrient removal of potentially functional bacteria. The obtained results suggest that SRpf accelerated the start-up process and significantly enhanced the biological nutrient removal in sequencing batch reactor (SBR). PO₄ ³⁻-P removal efficiency increased by over 12 % and total nitrogen removal efficiency increased by over 8 % in treatment reactor acclimated by SRpf compared with those without SRpf addition. The Illumina high-throughput sequencing analysis showed that SRpf played an essential role in shifts in the composition and diversity of bacterial community. The phyla of Proteobacteria and Actinobacteria, which were closely related to biological nutrient removal, were greatly abundant after SRpf addition. This study demonstrates that SRpf acclimation or addition might hold great potential as an efficient and cost-effective alternative for wastewater treatment plants (WWTPs) to meet more stringent operation conditions and legislations.