Evaluation of <Emphasis Type="Italic">smtA</Emphasis> expression and <Emphasis Type="Italic">E. coli</Emphasis> survival against cadmium ions

Cadmium and other heavy metals lead to environmental danger, and these heavy metals are a great threat to human and other animal’s health. Investigation of the relationship between survival of E. coli and metallothionein smtA gene expression against cadmium ion is the goal of this research. Survival of recombinant bacteria containing smtA gene was analyzed against various concentrations of cadmium chloride salt using optical density (OD). At the resistive range, recombinant bacteria were subjected to different treatments. At the logarithmic phase of bacterial growth, sampling, RNA extraction and cDNA synthesis were performed and smtA gene expression was then analyzed by real-time PCR using designed primers for smtA gene and Amp resistance (as the calibrator gene). Relative gene expression was calculated using the ??C_t method. The resistive range against cadmium chloride was 0.5–0.7 mM (minimum inhibitory concentration (MIC = 0.5 mM)). Survival and gene expression analysis showed that in induced bacteria, smtA expression was increased significantly that in turn conferred resistance to cadmium chloride prominently. There was a direct relationship between increased smtA gene expression and survival of the recombinant bacteria. Therefore, our result may help to confront to cadmium metal environmental pollution using overexpression of smtA gene expression in recombinant bacteria.     

Enzymatic degradation of polyhydroxyalkanoate using lipase from <Emphasis Type="Italic">Bacillus subtilis</Emphasis>

Polyhydroxyalkanoates (PHAs) are an important class of biodegradable polymers synthesized by a few bacteria under nutrient-limiting conditions. In this study, the lipase-catalysed degradation of PHA synthesized by Enterobacter sp. was monitored. For this, the lipase-encoding gene from Bacillus subtilis DI2 was PCR-amplified, cloned into a T vector system and sequenced. It was expressed in Escherichia coli DH5α cells, the recombinant enzyme was purified 24.25-fold, and its molecular weight was determined to be around 28 kDa. When PHA biodegradation studies were carried out with this enzyme, gel permeation chromatography showed 21.3 and 28.3 % molecular weight decrease and weight loss, respectively. Further, scanning electron micrographs revealed alterations in polymer surface morphology. Changes in molecular vibrations were noticed in the FTIR spectra. When the chemical shifts in NMR spectra were studied, a steep reduction in area under the peak at 1.57 ppm was observed. In the heating range of 30–930 °C employed during thermogravimetry analysis, the degraded sample showed a total of 45.82 % weight loss, as against 18.89 % for the native sample. The melting temperature (T _m) of the polymer was also brought down from 126.22 to 118.18 °C, as inferred from differential scanning calorimetry. Lipase-catalysed chain scission reactions could thus be used to generate low molecular weight functional biopolymers with wide-ranging pharmaceutical applications, such as in sustained drug release.     

Bacterial consortium expressing surface displayed,intra- and extracellular lipases and pseudopyronine B for the degradation of oil

The lipA gene, encoding a solvent-tolerant extracellular lipase from Proteus sp. SW1, was displayed on the cell surface of Escherichia coli by fusing it to an antigen 43 anchoring motif. The display of LipA on the Escherichia coli cell surface was directly confirmed by immunofluorescence microscopy and flow cytometry. After 6 days of incubation in media containing 1 % used cooking oil, an Escherichia coli strain expressing surface displayed lipase was able to degrade 27 % of the oil. The biosurfactant, pseudopyronine B, was purified from culture supernatants of Pseudomonas sp. SL31. Its critical micelle concentration was determined to be 1400 mg/l, and the surfactant was stable within a temperature range from 0 to 120 °C and a pH range of 3–11. Pseudopyronine B-containing crude media extracts efficiently removed up to 51 % of the cadmium from contaminated water. We demonstrated the oil degradation ability of the mixed culture of four bacterial strains, namely the recombinant Escherichia coli expressing cell surface displayed lipase (pKKJlipA), His-tagged lipase (pETlipA), extracellular lipase-producing Proteus sp. SW1, and pseudopyronine B-producing Pseudomonas sp. SL31 by culturing in LB media containing 1 % oil. The consortium degraded 29 % of oil in one day and reached 84 % after 7 days.     

A safety type genetically engineered bacterium with red fluorescence which can be used to degrade organophosphorus pesticides

To effectively biodegrade organophosphorus pesticides residue in environment, we constructed a genetically engineered bacterium (GEB) which can not only emit red fluorescence but also degrade organophosphorus pesticides residue, and this GEB can commit suicide when required. Two genes with different functions were placed under the control of different promoters. One was the dual gene expression vector pL-DsRed–pL-OPH in which genes coding for DsRed and organophosphorus hydrolase were independently placed downstream of two pL promoters. These genes could be expressed freely as long as the GEB was alive. The other was the conditional suicide plasmid pDS containing two suicide cassettes designed to induce bacteria to commit suicide when they detect arabinose. The lethal gene used in the suicide plasmid was the nuclease gene of Serratia marcescens without the leader-coding sequence. This was put under the control of the T7 promoter. Applying this type of secure GEB could potentially be a less hazardous environmental strategy in degrading pesticides and contamination.     

Long-term and short-term variations of Escherichia coli population structure in tropical coastal waters

In this study, monthly and daily samplings were carried out at Klang, an eutrophic estuary, and at Port Dickson, an oligotrophic coastal water system. Escherichia coli concentration was measured via culture method, and the phylogenetic structure of E. coli population was via Clermont typing. Average E. coli concentration at Klang was higher than Port Dickson (t = 2.97, df = 10, p < 0.05), and daily sampling did not show any apparent temporal variation at both sites. At Klang, salinity was inversely correlated with coliform (R ² = 0.216, df = 25, p < 0.05), suggesting that river flow was a mode of transport for coliform. Although E. coli concentration was higher at the eutrophic site, E. coli population structure at both Klang and Port Dickson were similar and showed neither long-term nor short-term variations. This study showed the predominance of commensal groups A and B1 in tropical coastal waters of Peninsular Malaysia.     

Antibiotic resistance and genetic diversity in water-borne Enterobacteriaceae isolates from recreational and drinking water sources

A total of 240 water-borne bacteria including 72 Escherichia coli, 83 Enterobacter, 30 Klebsiella, 36 Salmonella and 19 Shigella spp. isolates from drinking and recreational water sources were assessed for antibiotic resistance and genetic diversity. Escherichia coli (88.89 %) and species of Enterobacter (86.75 %), Klebsiella (83.33 %) and Salmonella (100 %) were resistant to cefadroxil, while >94 % Shigella spp. were resistant to cefaclor and cefuroxime. Ofloxacin was the most effective antibiotic against isolates of all the genera. Multiple antibiotic resistance index identified dug well, pond and piped water supplies as high risk sources of enteric pathogens. Random amplified polymorphic DNA analysis and restriction fragment length polymorphism of amplified 16S rRNA gene were studied for genetic relatedness of Enterobacteriaceae isolates. Primer P1254 identified 10, 16, 4, 4 and 1 distinct random amplified polymorphic DNA group(s) of E. coli, Enterobacter, Klebsiella, Salmonella and Shigella species, respectively. Unlike random amplified polymorphic DNA, restriction fragment length polymorphism using AluI and HaeIII could not segregate isolates in different genetic profiles. 16S rRNA gene of three Enterobacter spp. strains from different sources with similar restriction fragment length polymorphism but different random amplified polymorphic DNA patterns was sequenced, and identified as Enterobacter hormaechei strains skg0061, 0062 and 0063. The sequence information has been submitted to GenBank (HQ322393-95). Biochemically similar but genetically diverse Enterobacteriaceae members from drinking and recreational water sources exhibited varying antibiotic sensitivity. Contamination of water sources with such multiple antibiotic-resistant enteric pathogens poses threat to human health.     

Potency of constructed wetlands for deportation of pathogens index from rural,urban and industrial wastewater

Pathogen removal is essential for wastewater treatment and its potential reuse in agriculture. Three field-scale wastewater treatment systems consisting of free surface flow were operated around 1.5 years receiving water from urban domestic, rural domestic and industrial sources. The study was conducted to evaluate seasonal performance of constructed wetland systems in removing Escherichia coli, Enterococci and total coliforms under continuous hydraulic flow. Results displayed that all three wetlands gain recognition in removing pathogen load with high removal efficacy till water reaches output ports. Removal efficiencies were even higher, 66–93, 78–92 and 80–94% for E. coli, Enterococci and total coliforms, respectively, within constructed wetlands. Remarkably at shorter temporal scales in CW-A, greater homogeneity of pathogen concentrations was assessed at wetland outlet sites. In outlet ports, results displayed a highly effective removal of E. coli concentration 80–90% (June 2015), 86–92% (October 2015) and 79–92% (February 2016), Enterococci 80–94% (June 2015), 83–94% (October 2015) and 80–94% (February 2016) and total coliforms 85–93% (June 2015), 87–95% (October 2015) and 88–96% (February 2016). Positive correlation was observed between bacterial indicators (E. coli–Enterococci, r = 0.038; p < 0.01 and E. coli–total coliforms, r = 0.142; p < 0.01). Removal of bacterial indicators in constructed wetland was also displayed by PCA in which three-component analysis of variance was 98.39% and showed a clear decrease in measured parameter gradients toward samples from outlet ports. Constructed wetlands provide cost-effective treatment systems for reducing the pathogen load in wastewater in variable agro-climatic conditions and thus improve water quality.     

Stability at high-pressure,elastic behaviour and pressure-induced structural evolution of CsAlSi<Subscript>5</Subscript>O<Subscript>12</Subscript>, a potential host for nuclear waste

The elastic and structural behaviour of the synthetic zeolite CsAlSi₅O₁₂ (a = 16.753(4), b = 13.797(3) and c = 5.0235(17) Å, space group Ama2, Z = 2) were investigated up to 8.5 GPa by in situ single-crystal X-ray diffraction with a diamond anvil cell under hydrostatic conditions. No phase-transition occurs within the P-range investigated. Fitting the volume data with a third-order Birch–Murnaghan equation-of-state gives: V ₀ = 1,155(4) ų, K _T0 = 20(1) GPa and K′ = 6.5(7). The “axial moduli” were calculated with a third-order “linearized” BM-EoS, substituting the cube of the individual lattice parameter (a ³, b ³, c ³) for the volume. The refined axial-EoS parameters are: a ₀ = 16.701(44) Å, K _T0a = 14(2) GPa (β_a = 0.024(3) GPa^?1), K′ _a = 6.2(8) for the a-axis; b ₀ = 13.778(20) Å, K _T0b = 21(3) GPa (β_b = 0.016(2) GPa^?1), K′ _b = 10(2) for the b-axis; c ₀ = 5.018(7) Å, K _T0c = 33(3) GPa (β_c = 0.010(1) GPa^?1), K′ _c = 3.2(8) for the c-axis (K _T0a:K _T0b:K _T0c = 1:1.50:2.36). The HP-crystal structure evolution was studied on the basis of several structural refinements at different pressures: 0.0001 GPa (with crystal in DAC without any pressure medium), 1.58(3), 1.75(4), 1.94(6), 3.25(4), 4.69(5), 7.36(6), 8.45(5) and 0.0001 GPa (after decompression). The main deformation mechanisms at high-pressure are basically driven by tetrahedral tilting, the tetrahedra behaving as rigid-units. A change in the compressional mechanisms was observed at P ≤ 2 GPa. The P-induced structural rearrangement up to 8.5 GPa is completely reversible. The high thermo-elastic stability of CsAlSi₅O_12, the immobility of Cs at HT/HP-conditions, the preservation of crystallinity at least up to 8.5 GPa and 1,000°C in elastic regime and the extremely low leaching rate of Cs from CsAlSi₅O₁₂ allow to consider this open-framework silicate as functional material potentially usable for fixation and deposition of Cs radioisotopes.     

Distribution of cations at two tetrahedral sites in Ca2MgSi2O7-Ca2Fe3+AlSiO7 series synthetic melilite and its relation to incommensurate structure

Synthetic melilites on the join Ca₂MgSi₂O₇ (åkermanite: Ak)-Ca₂Fe³⁺AlSiO₇ (ferrialuminium gehlenite: FAGeh) were studied using X-ray powder diffraction and ⁵⁷Fe Mössbauer spectroscopic methods to determine the distribution of Fe³⁺ between two different tetrahedral sites (T1 and T2), and the relationship between ionic substitution and incommensurate (IC) structure. Melilites were synthesized from starting materials with compositions of Ak₁₀₀, Ak₈₀FAGeh₂₀, Ak₇₀FAGeh₃₀ and Ak₅₀FAGeh₅₀ by sintering at 1,170–1,350 °C and 1 atm. The average chemical compositions and end-member components, Ak, FAGeh and Geh (Ca₂Al₂SiO₇), of the synthetic melilites were Ca_2.015Mg_1.023Si_1.981O₇ (Ak₁₀₀), Ca_2.017Mg_0.788Fe _0.187 ³⁺ Al_0.221Si_1.791O₇ (Ak₇₈FAGeh₁₉Geh₃), Ca_1.995Mg_0.695Fe _0.258 ³⁺ Al_0.318Si_1.723O₇ (Ak₆₉FAGeh₂₅Geh₆) and Ca_1.982Mg_0.495Fe _0.449 ³⁺ Al_0.519Si_1.535O₇ (Ak₄₉FAGeh₄₄Geh₇), respectively. Rietveld refinements using X-ray powder diffraction data measured using CuK _α -radiation at room temperature converged successfully with goodness-of-fits of 1.15–1.26. The refined Fe occupancies at the T1 and T2 sites and the Mg and Si contents determined by electron microprobe analysis gave the site populations of [0.788Mg + 0.082Fe³⁺ + 0.130Al]_T1[0.104Fe³⁺ + 0.104Al + 1.792Si]_T2 for Ak₇₈FAGeh₁₉Geh₃, [0.695Mg + 0.127Fe³⁺ + 0.178Al]_T1[0.132Fe³⁺ + 0.144Al + 1.724Si]_T2 for Ak₆₉FAGeh₂₅Geh₆ and [0.495Mg + 0.202Fe³⁺ + 0.303Al]_T1[0.248Fe³⁺ + 0.216Al + 1.536Si]_T2 for Ak₄₉FAGeh₄₄Geh₇ (apfu: atoms per formula unit), respectively. The results indicate that Fe³⁺ is distributed at both the T1 and the T2 sites. The mean T1–O distance decreases with the substitution of Fe³⁺ + Al³⁺ for Mg²⁺ at the T1 site, whereas the mean T2–O distance increases with substitution of Fe³⁺ + Al³⁺ for Si⁴⁺ at the T2 site, causing decrease in the a dimension and increase in the c dimension. However, in spite of the successful Rietveld refinements for the X-ray powder diffraction data measured using CuK _α-radiation at room temperature, each Bragg reflection measured using CuK _α1-radiation at room temperature showed weak shoulders, which were not observed in those measured at 200 °C. The Mössbauer spectra of the melilites measured at room temperature consist of two doublets assigned to Fe³⁺ at the T1 site and two or three doublets to Fe³⁺ at the T2 site, implying the existence of multiple T1 and T2 sites with different site distortions. These facts can be interpreted in terms of the IC structure in all synthetic melilites at room temperature, respectively. The results of Mössbauer analysis indicate that the IC structure in melilite is caused by not only known multiple T1 site, but also multiple T2 site at room temperature.     

Exposure of rainbow trout to industrial wastewater is associated with immune-related gene expression and hematological changes

Inappropriate management of industrial effluents has been among major causes of water pollution and subsequent fish physiological and behavioral disorders and mortalities. This study investigated the effects of wastewater from a paper mill on immune-related gene expressions (lysozyme, tumor necrosis factor and heat shock protein 70) and hematological alterations, in juvenile rainbow trout (Oncorhynchus mykiss) during a 14-day exposure period. Following the determination of LC50, fish (135 ± 10 g body weight) were exposed to three effluent treatments: control (0), 10 and 25% of LC50, in laboratory conditions. The wastewater exposure initially increased lysozyme and tumor necrosis factor gene expression, and the expression of both genes was suppressed on the 14th day after exposure. There was a rise in heat shock protein 70 gene expression at the beginning of the experiment and then decreased to the level observed in the control group. Fish exposed to wastewater showed a significant increase in the levels of red blood cells, white blood cells and hematocrit three days following exposure, but the levels of these blood parameters significantly decreased at the end of the exposure period (P < 0.05). Our results indicated a range of immune-related gene toxicity and hematotoxicity in rainbow trout caused by the negative impacts of the industrial wastewater. Here we also discussed that poor biosecurity controls and inadequate treatments of effluents from industrial activities can lead to serious damages among wild populations.     

Construction of green fluorescent protein based bacterial biosensor for heavy metal remediation

Environmental contamination by heavy metals is a worldwide problem. Therefore, it is necessary to develop sensitive, effective and inexpensive methods, which can efficiently monitor and determine the level of hazardous metals in the environment. Conventional techniques to analyze metals, suffer from the disadvantages of high cost. Alternatively, development of simple system for monitoring heavy metals pollution is therefore needed. The present approach is based on the use of bacteria that are genetically engineered so that a measurable signal is produced when the bacteria are in contact with the bioavailable metal ions. Reporter genes are widely used as genetic tools for quantification and detection of specific cell population, gene expression and constructing whole cell biosensors as specific and sensitive devices for measuring biologically relevant concentrations of pollutants. An attempt has been made to construct the reporter gene enhanced green fluorescent protein and was expressed under the control of cadR gene, responsible for cadmium resistance. Recombinant strain Escherichia coli cadR30 was used, that carried cadR gene in pET30b expression vector and cloned. Clones confirmed by the expression of enhanced green fluorescent protein was detected under ultraviolet illumination and separated on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The construction of green fluorescent protein based Escherichia coli bacterial biosensor was developed based on green fluorescent protein expression under the control cadR gene of Pseudomonas aeruginosa BC15. The constructed bacterial biosensor is useful and applicable in determining the availability of heavy metals in soil and wastewater.     

The P–V–T equation of state of CaPtO3 post-perovskite

Orthorhombic post-perovskite CaPtO₃ is isostructural with post-perovskite MgSiO₃, a deep-Earth phase stable only above 100 GPa. Energy-dispersive X-ray diffraction data (to 9.4 GPa and 1,024 K) for CaPtO₃ have been combined with published isothermal and isobaric measurements to determine its P–V–T equation of state (EoS). A third-order Birch–Murnaghan EoS was used, with the volumetric thermal expansion coefficient (at atmospheric pressure) represented by α(T) = α₀ + α₁(T). The fitted parameters had values: isothermal incompressibility, $ K_{{T_{0} }} $  = 168.4(3) GPa; $ K_{{T_{0} }}^{\prime } $  = 4.48(3) (both at 298 K); $ \partial K_{{T_{0} }} /\partial T $  = ?0.032(3) GPa K^?1; α₀ = 2.32(2) × 10^?5 K^?1; α₁ = 5.7(4) × 10^?9 K^?2. The volumetric isothermal Anderson–Grüneisen parameter, δ _T , is 7.6(7) at 298 K. $ \partial K_{{T_{0} }} /\partial T $ for CaPtO₃ is similar to that recently reported for CaIrO₃, differing significantly from values found at high pressure for MgSiO₃ post-perovskite (?0.0085(11) to ?0.024 GPa K^?1). We also report axial P–V–T EoS of similar form, the first for any post-perovskite. Fitted to the cubes of the axes, these gave $ \partial K_{{aT_{0} }} /\partial T $  = ?0.038(4) GPa K^?1; $ \partial K_{{bT_{0} }} /\partial T $  = ?0.021(2) GPa K^?1; $ \partial K_{{cT_{0} }} /\partial T $  = ?0.026(5) GPa K^?1, with δ _T  = 8.9(9), 7.4(7) and 4.6(9) for a, b and c, respectively. Although $ K_{{T_{0} }} $ is lowest for the b-axis, its incompressibility is the least temperature dependent.     

Structural evolution of a 2M 1 phengite mica up to 11 GPa: an in situ single-crystal X-ray diffraction study

The structural evolution at high pressure of a natural 2M ₁-phengite [(K_0.98Na_0.02)_Σ=1.00(Al_1.55Mg_0.24Fe_0.21Ti_0.02)_Σ=2.01(Si_3.38Al_0.62)O₁₀(OH)₂; a = 5.228(2), b = 9.057(3), c = 19.971(6)Å, β = 95.76(2)°; space group: C2/c] from the metamorphic complex of Cima Pal (Sesia Zone, Western Alps, Italy) was studied by single-crystal X-ray diffraction with a diamond anvil cell under hydrostatic conditions up to ~11 GPa. A series of 12 structure refinements were performed at selected pressures within the P range investigated. The compressional behaviour of the same phengite sample was previously studied up to ~25 GPa by synchrotron X-ray powder diffraction, showing an irreversible transformation with a drastic decrease of the crystallinity at P > 15–17 GPa. The elastic behaviour between 0.0001 and 17 GPa was modelled by a third-order Birch–Murnaghan Equation of State (BM-EoS), yielding to K _T0 = 57.3(10) GPa and K′ = ?K _T0/?P = 6.97(24). The single-crystal structure refinements showed that the significant elastic anisotropy of the 2M ₁-phengite (with β(a):β(b):β(c) = 1:1.17:4.60) is mainly controlled by the anisotropic compression of the K-polyhedra. The evolution of the volume of the inter-layer K-polyhedron as a function of P shows a negative slope, Fitting the P–V(K-polyhedron) data with a truncated second-order BM-EoS we obtain a bulk modulus value of K _T0(K-polyhedron) = 26(1) GPa. Tetrahedra and octahedra are significantly stiffer than the K-polyhedron. Tetrahedra behave as quasi-rigid units within the P range investigated. In contrast, a monotonic decrease is observed for the octahedron volume, with K _T0 = 120(10) GPa derived by a BM-EoS. The anisotropic response to pressure of the K-polyhedron affects the P-induced deformation mechanism on the tetrahedral sheet, consisting in a cooperative rotation of the tetrahedra and producing a significant ditrigonalization of the six-membered rings. The volume of the K-polyhedron and the value of the ditrigonal rotation parameter (α) show a high negative correlation (about 93%), though a slight discontinuity is observed at P >8 GPa. α increases linearly with P up to 7–8 GPa (with ?α/?P ≈ 0.7°/GPa), whereas at higher Ps a “saturation plateau” is visible. A comparison between the main deformation mechanisms as a function of pressure observed in 2M ₁- and 3T-phengite is discussed.     

Between-Population Differences in Multi-stressor Tolerance During Embryo Development in the American Horseshoe Crab, <Emphasis Type="Italic">Limulus polyphemus</Emphasis>

The American horseshoe crab, Limulus polyphemus, is found along the Atlantic and Gulf of Mexico coasts in genetically isolated populations. Eggs are laid in shoreline beaches that expose developing embryos to combinations of environmental stressors. Whether populations of L. polyphemus differ in multi-stressor tolerance had never been tested. We assessed the multi-stressor tolerance of L. polyphemus embryos from a population in Delaware Bay (DE) and determined whether these differed from the multi-stressor tolerance of embryos from a more southerly Florida Gulf Coast (FGC) population. We monitored the field sediment temperatures and determined multi-stressor tolerance of DE embryos, then compared these to published data for FGC embryos. For multi-stressor tolerance, we assessed development success of embryos in 2-week exposures to 36 full-factorial combinations of temperature (20, 25, 30, 35 °C), salinity (5, 15, and 34 ppt), and ambient O₂ (5, 13, and 21% O₂), followed by 2 weeks in recovery conditions. Sediment temperatures in the DE site ranged from 9.5 to 46 °C, with extended periods exceeding 35 °C. Development success was similar between the DE and FGC populations in 14 of 26 multi-stressor combinations. The DE embryos were generally more successful in conditions that included high temperature or moderate hyposalinity, whereas the FGC embryos were generally more successful in conditions that included extreme hyposalinity. This suggests that although multi-stressor tolerances are generally similar between the two populations, specific differences exist that correlate more with differences in nest microenvironment than latitude.     

Impact of pit-toilet leachate on groundwater chemistry and role of vadose zone in removal of nitrate and E. coli pollutants in Kolar District, Karnataka, India

Assessment of chemistry of groundwater infiltrated by pit-toilet leachate and contaminant removal by vadose zone form the focus of this study. The study area is Mulbagal Town in Karnataka State, India. Groundwater level measurements and estimation of unsaturated permeability indicated that the leachate recharged the groundwater inside the town at the rate of 1 m/day. The average nitrate concentration of groundwater inside the town (148 mg/L) was three times larger than the permissible limit (45 mg/L), while the average nitrate concentration of groundwater outside the town (30 mg/L) was below the permissible limit. The groundwater inside the town exhibited E. coli contamination, while groundwater outside the town was free of pathogen contamination. Infiltration of alkalis (Na⁺, K⁺) and strong acids (Cl^?, SO₄ ^2?) caused the mixed Ca–Mg–Cl type (60 %) and Na–Cl type (28 %) facies to predominate groundwater inside the town, while, Ca–HCO₃ (35 %), mixed Ca–Mg–Cl type (35 %) and mixed Ca–Na–HCO₃ type (28 %) facies predominated groundwater outside/periphery of town. Reductions in E. coli and nitrate concentrations with vadose zone thickness indicated its participation in contaminant removal. A 4-m thickness of unsaturated sand + soft, disintegrated weathered rock deposit facilitates the removal of 1 log of E. coli pathogen. The anoxic conditions prevailing in the deeper layers of the vadose zone (>19 m thickness) favor denitrification resulting in lower nitrate concentrations (28–96 mg/L) in deeper water tables (located at depths of ?29 to ?39 m).     

Modeling chromium(VI) reduction by Escherichia coli 33456 using ceramic pearl as a supporting medium

A mathematical model was developed to describe the reduction of Cr(VI) by Escherichia coli (E. coli) 33456 in a fixed biofilm reactor. A laboratory-scale column reactor was conducted to verify the model system. The batch kinetic tests were independently conducted to determine the biokinetic parameters used in the model simulation. With the assumed values of initial biofilm thickness (L _f0), the mathematical model simulated well the experimental results for Cr(VI) effluent concentration, effluent concentration of suspended E. coli cells, and Cr(III) production. The concentration of suspended E. coli cells reached up to 1.2 mg cell/L while the thickness of attached E. coli cells was estimated to be 32.6 μm at a steady-state condition. At the steady state, the removal efficiency of Cr(VI) was about 92 % and the effluent concentration of Cr(III) was approximately 1.6 mg/L. The approaches presented in this study can be employed for the design of a pilot-scale or full-scale fixed biofilm reactor to treat Cr(VI)-containing wastewater.     

Thermal equation of state of CaIrO<Subscript>3</Subscript> post-perovskite

The pressure–volume–temperature (P–V–T) relation of CaIrO₃ post-perovskite (ppv) was measured at pressures and temperatures up to 8.6 GPa and 1,273 K, respectively, with energy-dispersive synchrotron X-ray diffraction using a DIA-type, cubic-anvil apparatus (SAM85). Unit-cell dimensions were derived from the Le Bail full profile refinement technique, and the results were fitted using the third-order Birth-Murnaghan equation of state. The derived bulk modulus \( K_{T0} \) at ambient pressure and temperature is 168.3 ± 7.1 GPa with a pressure derivative \( K_{T0}^{\prime } \) = 5.4 ± 0.7. All of the high temperature data, combined with previous experimental data, are fitted using the high-temperature Birch-Murnaghan equation of state, the thermal pressure approach, and the Mie-Grüneisen-Debye formalism. The refined thermoelastic parameters for CaIrO₃ ppv are: temperature derivative of bulk modulus \( (\partial K_{T} /\partial T)_{P} \) = ?0.038 ± 0.011 GPa K^?1, \( \alpha K_{T} \) = 0.0039 ± 0.0001 GPa K^?1, \( \left( {\partial K_{T} /\partial T} \right)_{V} \) = ?0.012 ± 0.002 GPa K^?1, and \( \left( {\partial^{2} P/\partial T^{2} } \right)_{V} \) = 1.9 ± 0.3 × 10^?6 GPa² K^?2. Using the Mie-Grüneisen-Debye formalism, we obtain Grüneisen parameter \( \gamma_{0} \) = 0.92 ± 0.01 and its volume dependence q = 3.4 ± 0.6. The systematic variation of bulk moduli for several oxide post-perovskites can be described approximately by the relationship K _T0  = 5406.0/V(molar) + 5.9 GPa.     

Toxicity,biochemical and clastogenic response of chlorpyrifos and carbendazim in milkfish Chanos chanos

Carbendazim and Chlorpyrifos are some of the most widespread environmental contaminants of major concern to human and animal reproductive health. Acute toxicity test results for pesticides were evaluated by the Probit analysis method and 96 h LC₅₀ values for C. chanos exposed to chlorpyrifos was 3.73 and 11.5 μg l^?1 for carbendazim. Chlorpyrifos and carbendazim significantly decreased total protein, catalase, glutathione S-transferase and acetyl choline esterase and induced lipid peroxidation. Maximum effects of protein, catalase, lipid peroxidation, acetyl choline esterase and glutathione s-transferase were obtained in response to 23.68 μg l^?1 of chlorpyrifos and 43.68 μg l^?1 of carbendazim. Micronuclei assay results have shown increased abnormality with increasing doses of chlorpyrifos and carbendazim. Maximum increasing in micronuclei was observed in chlorpyrifos exposed C. chanos. This study showed that chlorpyrifos and carbendazim induced alterations in the activity of antioxidant enzymes and could induce clastogenicity.     

Thermo-elastic behaviour of Be2BO3OH (hambergite) up to 7 GPa and 1,100 K

The thermo-elastic behaviour of Be₂BO₃(OH)_0.96F_0.04 (i.e. natural hambergite, Z = 8, a = 9.7564(1), b = 12.1980(2), c = 4.4300(1) Å, V = 527.21(1) ų, space group Pbca) has been investigated up to 7 GPa (at 298 K) and up to 1,100 K (at 0.0001 GPa) by means of in situ single-crystal X-ray diffraction and synchrotron powder diffraction, respectively. No phase transition or anomalous elastic behaviour has been observed within the pressure range investigated. P?V data fitted to a third-order Birch–Murnaghan equation of state give: V ₀ = 528.89(4) ų, K _T0 = 67.0(4) GPa and K′ = 5.4(1). The evolution of the lattice parameters with pressure is significantly anisotropic, being: K _T0(a):K _T0(b):K _T0(c) = 1:1.13:3.67. The high-temperature experiment shows evidence of structure breakdown at T > 973 K, with a significant increase in the full-width-at-half-maximum of all the Bragg peaks and an anomalous increase in the background of the diffraction pattern. The diffraction pattern was indexable up to 1,098 K. No new crystalline phase was observed up to 1,270 K. The diffraction data collected at room-T after the high-temperature experiment showed that the crystallinity was irreversibly compromised. The evolution of axial and volume thermal expansion coefficient, α, with T was described by the polynomial function: α(T) = α ₀ + α ₁ T ^?1/2. The refined parameters for Be₂BO₃(OH)_0.96F_0.04 are: α ₀ = 7.1(1) × 10^?5 K^?1 and α ₁ = ?8.9(2) × 10^?4 K ^?1/2 for the unit-cell volume, α ₀(a) = 1.52(9) × 10^?5 K^?1 and α ₁(a) = ?1.4(2) × 10^?4 K ^?1/2 for the a-axis, α ₀(b) = 4.4(1) × 10^?5 K^?1 and α ₁(b) = ?5.9(3) × 10^?4 K ^?1/2 for the b-axis, α ₀(c) = 1.07(8) × 10^?5 K^?1 and α ₁(c) = ?1.5(2) × 10^?4 K ^?1/2 for the c-axis. The thermo-elastic anisotropy can be described, at a first approximation, by α ₀(a):α ₀(b):α ₀(c) = 1.42:4.11:1. The main deformation mechanisms in response to the applied temperature, based on Rietveld structure refinement, are discussed.     

Identification and fate of antibiotic residue degradation during composting and vermicomposting of chicken manure

Oxytetracycline (OCT) is a broad-spectrum antibiotic commonly used for broiler production to enhance growth and feeding efficacy. Concern has been expressed that the parent compounds of antibiotics such as OCT or their bioactive metabolites may be excreted through animal feces or urine with negative consequences for the environment when applied to agricultural lands. An integrated system involving a combination of thermophilic composting and vermicomposting using Eisenia fetida was investigated as a strategy for reducing the concentrations of oxytetracycline and its metabolites (4-epi-oxytetracycline [EOTC], α-apo-oxytetracycline [α-Apo-OTC] and β-apo-oxytetracycline [β-Apo-OTC]) in chicken manure. Treatments consisted of combinations of chicken manure and waste paper to produce waste mixtures with C: N ratios of 20, 30, 40, 50, 60 and 70 (T1, T2, T3, T4, T5 and T6, respectively). These were subjected to thermophilic composting for 20 days followed by vermicomposting with E. fetida for 7 weeks. The oxytetracycline concentration at the start of the experiment was in the range of 123.3–35.2 mg/kg, which reduced to 44–25.3 mg/kg after the thermophilic composting, and further reduced to 35.4–20.7 mg/kg at the end of the vermicomposting stage. The maximum overall percentage reduction of residual oxytetracycline in the final product was recorded in T3 (C:N ratio 40). The maximum percentage reduction of 84.3% was recorded in C: N ratio of 40 (T3) in which the metabolite degradation products were reduced to 3.1 mg/kg of 4-epi-oxytetracycline (EOTC), 3.9 mg/kg of α-apo-oxytetracycline (α-Apo-OTC) and 4 mg/kg of β-apo-oxytetracycline (β-Apo-OTC).