The effect of microemulsion on the biodegradation of total petroleum hydrocarbons (TPH) in nitrate-induced bioremediation of marine sediment was investigated in this study. It was shown that the microemulsion formed with non-ionic surfactant polyoxyethylene sorbitan monooleate (Tween 80), 1-pentanol, linseed oil, and either deionized water or seawater was stable when subjected to dilution by seawater. Desorption tests revealed that microemulsion was more effective than the Tween 80 solution or the solution containing Tween 80 and 1-pentanol to desorb TPH from marine sediment. In 3 weeks of bioremediation treatment, the injection of microemulsion and NO₃ ⁻ seems to have delayed the autotrophic denitrification between NO₃ ⁻ and acid volatile sulfide (AVS) in sediment compared to the control with NO₃ ⁻ injection alone. However, after 6 weeks of treatment, the delaying effect of microemulsion on the autotrophic denitrification process was no longer observed. In the meantime, the four injections of microemulsion and NO₃ ⁻ resulted in as high as 29.73 % of TPH degradation efficiency, higher than that of two injections of microemulsion and NO₃ ⁻ or that of four or two injections of NO₃ ⁻ alone. These results suggest that microemulsion can be potentially applied to enhance TPH degradation in the nitrate-induced bioremediation of marine sediment.

Two contrasting ecotypes of Dianthus carthusianorum L., metallicolous (M) and nonmetallicolous (NM), were cultivated in hydroponics at 0–50 μM Cd for 14 days to compare their Cd accumulation, sensitivity and tolerance mechanisms. While both ecotypes contained similar concentrations of Cd in the shoots and roots, the M ecotype was more Cd-tolerant (as measured by fresh weight production and root and leaf viability). Both ecotypes accumulated phytochelatins (PCs) in response to Cd with a higher amount thereof found in the NM ecotype. Concentrations of PCs remained unchanged with increasing Cd concentrations in the root tissues, but their content in the shoots increased. The addition of L-buthionine-sulfoximine (BSO) diminished glutathione (GSH) accumulation and arrested PC production, which increased the sensitivity to Cd of the NM, but not M ecotype. Organic acids (malate and citrate) as well as proline accumulation did not change significantly after Cd exposition and was at the same level in both ecotypes. The enhanced Cd tolerance of the M ecotype of D. carthusianorum cannot be explained in terms of restricted Cd uptake and differential production of PCs, organic acids or proline; some other mechanisms must be involved in its adaptation to the high Cd content in the environment.

Aedes aegypti is the vector for transmitting dengue, chikungunya, and yellow fever. These diseases’ transmission has increased predominantly in urban and semi-urban areas as a major public health concern. In present investigation, Trichoderma atroviride culture filtrates were used for the synthesis of silver nanoparticle. Moreover, T. atroviride is a free-living and rapidly growing fungi common in soil and root ecosystem. This fungi is an exceptionally good model for biocontrol and more significant as a bioagent. T. atroviride was grown in malt extract. T. atroviride culture filtrates were exposed to silver nitrates solution for 24 h at 25 °C for the synthesis of silver nanoparticles (AgNPs). These AgNPs were characterized to find their unique properties with UV-visible spectrophotometer and transmission electron microscope (TEM) analysis. The T. atroviride culture filtrates have formed hexagonal (diamond shape) AgNPs with the range of size of 14.01–21.02 nm. These AgNPs have shown significant efficacies against first, second, third, and fourth instar larvae of A. aegypti. The LC₉₀ and LC₉₉ values for the first instar were 1 and 3 ppm, second instar 2 and 3.18 ppm, third instar 3.12 and 4.12 ppm, and fourth instar 6.30 and 6.59 ppm, respectively, after an exposure of 7 h. The confocal laser scanning microscopy (CLSM) studies were verdict that these AgNPs embedded in the cuticle of larvae and cause instant lethality in 7 h. Present investigations have demonstrated that the AgNPs of T. atroviride culture filtrates synthesized can be used for larvae control of A. aegypti. T. atroviride is synthesized to silver nanoparticles to be a promising new candidate for application in mosquito control. We therefore suggested that the ability of T. atroviride culture filtrates in synthesis can also be explored for synthesizing silver nanoparticles for commercial exploitation.

Trichoderma asperellum H15, a previously isolated strain characterized by its high tolerance to low (LMW) and high molecular weight (HMW) PAHs, was tested for its ability to degrade 3–5 ring PAHs (phenanthrene, pyrene, and benzo[a]pyrene) in soil microcosms along with a biostimulation treatment with sugarcane bagasse. T. asperellum H15 rapidly adapted to PAH-contaminated soils, producing more CO₂than uncontaminated microcosms and achieving up to 78 % of phenanthrene degradation in soils contaminated with 1,000 mg Kg⁻¹after 14 days. In soils contaminated with 1,000 mg Kg⁻¹of a three-PAH mixture, strain H15 was shown to degrade 74 % phenanthrene, 63 % pyrene, and 81 % of benzo[a]pyrene. Fungal catechol 1,2 dioxygenase, laccase, and peroxidase enzyme activities were found to be involved in the degradation of PAHs by T. asperellum. The results demonstrated the potential of T. asperellum H15 to be used in a bioremediation process. This is the first report describing the involvement of T. asperellum in LMW and HMW-PAH degradation in soils. These findings, along with the ability to remove large amounts of PAHs in soil found in the present work provide enough evidence to consider T. asperellum as a promising and efficient PAH-degrading microorganism.

High level of heavy metals in industrial sludge was the obstacle of sludge disposal and resource recycling. In this study, iminodisuccinic acid (IDS), a biodegradable chelating ligand, was used to remove heavy metals from industrial sludge generated from battery industry. The extraction of cadmium, copper, nickel, and zinc from battery sludge with aqueous solution of IDS was studied under various conditions. It was found that removal efficiency greatly depends on pH, chelating agent’s concentration, as well as species distribution of metals. The results showed that mildly acidic and neutral systems were not beneficial to remove cadmium. About 68 % of cadmium in the sample was extracted at the molar ratio of IDS to heavy metals 7:1 without pH adjustment (pH 11.5). Copper of 91.3 % and nickel of 90.7 % could be removed by IDS (molar ratio, IDS: metals = 1:1) with 1.2 % phosphoric acid effectively. Removal efficiency of zinc was very low throughout the experiment. Based on the experimental results, IDS could be a potentially useful chelant for heavy metal removal from battery industry sludge.

Degradation and mineralization behavior of selected nematicides was studied in soil samples from fields cultivated with banana, potato, and coffee. Degradation assays in most of the studied soils revealed shorter half-lives for carbofuran (CBF) and ethoprophos (ETP) in samples with a history of treatment with these compounds, which may have been caused by enhanced biodegradation. A short half-life value for CBF degradation was also observed in a banana field with no previous exposure to this pesticide, but with a recent application of the carbamate insecticide oxamyl, which supports the hypothesis that preexposure to oxamyl may cause microbial adaptation towards degradation of CBF, an observation of a phenomenon not yet tested according to the literature reviewed. Mineralization assays for CBF and terbufos (TBF) revealed that history of treatment with these nematicides did not cause higher mineralization rates in preexposed soils when compared to unexposed ones, except in the case of soils from coffee fields. Mineralization half-lives for soils unexposed to these pesticides were significantly shorter than most reports in the literature in the same conditions. Mineralization rates for soils with a previous exposure to these pesticides were also obtained, adding to the very few reports found. This paper contributes valuable data to the low number of reports dealing with pesticide fate in soils from tropical origin.

The applicability of an in situ electrokinetic process with a parallel electrode configuration was evaluated to treat an As-, Cu-, and Pb-contaminated paddy rice field in full scale (width, 17 m; length, 12.2 m; depth, 1.6 m). A constant voltage of 100 V was supplied and electrodes were spaced 2 m apart. Most As, Cu, and Pb were bound to Fe oxide and the major clay minerals in the test site were kaolinite and muscovite. The electrokinetic system removed 48.7, 48.9, and 54.5 % of As, Cu, and Pb, respectively, from the soil during 24 weeks. The removal of metals in the first layer (0–0.4 m) was higher than that in the other three layers because it was not influenced by groundwater fluctuation. Fractionation analysis showed that As and Pb bound to amorphous Fe and Al oxides decreased mainly, and energy consumption was 1.2 kWh/m³. The standard deviation of metal concentration in the soil was much higher compared to the hexagonal electrode configuration because of a smaller electrical active area; however, the electrode configuration removed similar amounts of metals compared to the hexagonal system. From these results, it was concluded that the electrokinetic process could be effective at remediating As-, Cu-, and Pb-contaminated paddy rice field in situ.

Mudflats are ecologically important habitats that are susceptible to oil pollution, but intervention is difficult in these fine-grained sediments, and so clean-up usually relies on natural attenuation. Therefore, we investigated the impact of crude oil on the bacterial, diatom and archaeal communities within the upper parts of the diatom-dominated sediment and the biofilm that detached from the surface at high tide. Biodegradation of petroleum hydrocarbons was rapid, with a 50 % decrease in concentration in the 0–2-mm section of sediment by 3 days, indicating the presence of a primed hydrocarbon-degrading community. The biggest oil-induced change was in the biofilm that detached from the sediment, with increased relative abundance of several types of diatom and of the obligately hydrocarbonoclastic Oleibacter sp., which constituted 5 % of the pyrosequences in the oiled floating biofilm on day 3 compared to 0.6 % in the non-oiled biofilm. Differences in bacterial community composition between oiled and non-oiled samples from the 0–2-mm section of sediment were only significant at days 12 to 28, and the 2–4-mm-sediment bacterial communities were not significantly affected by oil. However, specific members of the Chromatiales were detected (1 % of sequences in the 2–4-mm section) only in the oiled sediment, supporting other work that implicates them in anaerobic hydrocarbon degradation. Unlike the Bacteria, the archaeal communities were not significantly affected by oil. In fact, changes in community composition over time, perhaps caused by decreased nutrient concentration and changes in grazing pressure, overshadowed the effect of oil for both Bacteria and Archaea. Many obligate hydrocarbonoclastic and generalist oil-degrading bacteria were isolated, and there was little correspondence between the isolates and the main taxa detected by pyrosequencing of sediment-extracted DNA, except for Alcanivorax, Thalassolituus, Cycloclasticus and Roseobacter spp., which were detected by both methods.

To study the impact of oxygen regimes on the removal of polycylic aromatic hydrocarbons (PAHs) in oil-spill-affected coastal marine sediments, we used a thin-layer incubation method to ensure that the incubated sediment was fully oxic, anoxic, or was influenced by oxic-anoxic switches without sediment stirring. Hydrocarbon content and microbial assemblages were followed during 60 days to determine PAH degradation kinetics and microbial community dynamics according to the oxygenation regimes. The highest PAH removal, with 69 % reduction, was obtained at the end of the experiment under oxic conditions, whereas weaker removals were obtained under oscillating and anoxic conditions (18 and 12 %, respectively). Bacterial community structure during the experiment was determined using a dual 16S rRNA genes/16S rRNA transcripts approach, allowing the characterization of metabolically active bacteria responsible for the functioning of the bacterial community in the contaminated sediment. The shift of the metabolically active bacterial communities showed that the selection of first responders belonged to Pseudomonas spp. and Labrenzia sp. and included an unidentified Deltaproteobacteria—irrespective of the oxygen regime—followed by the selection of late responders adapted to the oxygen regime. A novel unaffiliated phylotype (B38) was highly active during the last stage of the experiment, at which time, the low-molecular-weight (LMW) PAH biodegradation rates were significant for permanent oxic- and oxygen-oscillating conditions, suggesting that this novel phylotype plays an active role during the restoration phase of the studied ecosystem.

The weight; testis/body coefficient; levels of LDH, SDH, SODH, G-6PD, and testosterone; cell cycle; and cell apoptosis of the male mice were influenced after being treated with 200 mg/[kg/day] of rare earths suspension for 3 weeks. The “Raman fingerprints” of the human sperm DNA exposed to 0.040 mg/ml CeCl₃ were very different from those of the untreated; the Raman bands at 789 cm⁻¹ (backbone phosphodiester), PO₄ backbone at 1,094 cm⁻¹, methylene deformation mode at 1,221 cm⁻¹, methylene deformation mode at 1,485 cm⁻¹, and amide II at 1,612 cm⁻¹, of which intensities and shifts were changed, might be the diagnostic biomarkers or potential therapeutic targets. The injury mechanism might be that the rare earths influence the oxidative stress and blood testosterone barrier, tangle the big biomolecule concurrently, which might cause the testicular cells and vascular system disorder and/or dysfunction, and at the same time change the physical and chemical properties of the sperm directly.