Biodegradation of 2-methylisoborneol by single bacterium in culture media and river water environment

2-Methylisoborneol (2-MIB) is a typical odorant in water sources. It is difficult for conventional water treatment to remove it. In this study, three strains capable of removing 2-MIB were isolated from activated carbon of sand filter. They were identified to be Shinella zoogloeoides, Bacillus idriensis and Chitinophagaceae bacterium based on 16S rRNA gene sequence analysis. The biodegradation of 2-MIB was improved with the presence of external carbon (glycerol, glucose, etc.). In the period of 20 days, Bacillus idriensis can remove 2 mg L^?1 2-MIB to 368.2 and 315.4 μg L^?1 in mineral salts medium without and with glycerol. Chitinophagaceae bacterium can remove it to 265.6 and 185.4 μg L^?1 without and with glucose. The enzymatic activity of B. Idriensis was lower when external carbon coexisted with 2-MIB. This indicated that a carbon source can inhibit the use of 2-MIB, but it can provide rich nutrients for the growth of bacteria.     

Dégradation des eaux de rejets issues d’une raffinerie d’huile de coton par plasma d’arc électrique rampant à pression atmosphérique

Wastewater samples from liquid effluents of cotton oil refinery in Far-Northern Cameroon were exposed to a gliding arc discharge for various exposure times in a cold plasma reactor. The analysed results showed high levels of organic pollution parameters (TOC = 4635 mg/L, COD = 6943, 98 mg/L) before treatment. More than 56% TOC and 75% COD abatement were obtained after 30 min treatment in batch conditions with a laboratory reactor. The resultant pollution abatement is attributed both to strong oxidizing effects of °OH and NO° radicals formed in the plasma and their derivatives (H₂O₂, ONO₂H and NO₃H). The conductivity and TDS increase linearly and the pH, TOC and COD decrease with increasing exposure time to the discharge. The oxidation obeys a pseudo first-order kinetics law (kinetic rate: k_1DCO = 0, 0381 min^?1 and k_1COT = 0, 0245 min^?1).     

Model experiments with CaO,MgO and calcinated dolomite for fluoride removal in a wet scrubbing system with sea water in recirculation

Fluoride removal was studied from saline waters using CaO, MgO and calcined natural dolomite (all fired at 1273 K), as an alternative for lime slurry neutralization process. Fluoride in the form of HF was added to sea water, saline groundwater or distilled water from 50 to 158 mg dm^?3. The amount of added CaO, MgO and CaO·MgO varied from 80 to 560 mg dm^?3. Concentrations of soluble fluoride, calcium, magnesium and pH were determined in supernatant. X-ray diffraction was used to identify the precipitated solids. All three processes show very good removal of fluoride from saline water, within 90 min designed for technological process (soluble fluoride varied from 5 to 25 mg dm^?3). It can be assumed that fluoride is either present in the form of an amorphous salt or is incorporated into the crystal lattice of one of the identified solids (CaCO₃, CaCO₃·H₂O, Mg(OH)₂, Mg₂SiO₄).     

Assessment of heavy metals contamination and its effects on oyster (Saccostrea cucullata) biometry parameters in the Asaluyeh port coasts,Persian Gulf,Iran

The current study examines biometric parameters and concentration of some heavy metals in soft tissues of Saccostrea cucullata in the Asaluyeh coast, Persian Gulf, Iran. The metals concentration in the soft tissue of the Saccostrea cucullata ranged as: Zn: 765–3411 mg kg^?1, Cu: 120.3–580.6 mg kg^?1, Cd: 0.13–3.5 mg kg^?1, As: 0.39–3.3 mg kg^?1, Pb: 0.05–1.64 mg kg^?1, Ni: 0.02–0.44 mg kg^?1, V: 0.06–0.32 mg kg^?1, Cr: 0.02–0.16 mg kg^?1 and Hg: 0.002–0.068 mg kg^?1. The results showed that the concentration of total heavy metals in oysters of the control station (CA) is usually lower. The results also indicated lack of correlation between oyster biometric parameters and bioaccumulated heavy metals, except between Cu and longitudinal diameter (R = 0.77). The concentration of heavy metals is higher than limits recommended by the World Health Organization, except for Cd and Pb.     

Naturally Pb-contaminated soils in uranium and thorium anomaly

The paper reports an examination of the primary sources of stable lead (Pb) occurring in rocks and soils on dairy farms in the municipalities of Pedra and Venturosa in Pernambuco, Brazil. Lead in rock and soil was quantified by flame atomic absorption spectrophotometry. The Pb concentration in calcium silicate rock varied from 21 to 1124.00 mg.kg^?1 and soil varied from 18 to 96 mg.kg^?1. The lead concentration in granite rock varied from 6 to 440 mg.kg^?1 and soil varied from 8 to 15 mg.kg^?1. The results point to the rocks as the primary sources of lead.     

Quantifying spatial-temporal changes of aboveground carbon stocks using Landsat time series data: A case study of Miombo woodlands

ABSTRACT

There is a need for accurate reporting of the second-growth forest in accounting for the contribution of secondary forests to achieving global carbon sequestration strategies. This study develops a model relating aboveground live biomass (AGLB) to Landsat reflectance measurements, and this method is used on multi spatial-temporal Landsat data (1998, 2001, 2004, 2011 and 2016) to assess changes in Miombo woodlands in Zambia. Results showed that the enhanced vegetation index was a better predictor of AGLB (r² = 0.96; RMSE = 0.24 t ha^?1) than the other assessed vegetation indices. Forest carbon stocks increased by an average rate of 3.65 ± standard error (SE): 0.56 t ha^?1 yr^?1 from 1998 to 2001, but a continual decline was evident for the periods 2001–2004 (?0.60 t ha^?1 yr^?1), 2004–2011 (?0.88 t ha^?1 yr^?1) and 2011–2016 (?2.03 t ha^?1 yr^?1). The study provides an empirical model for evaluating carbon stock changes.     

Mn and Ni contents in soils of a qualified denomination of origin region: Rioja D.O.Ca,Spain

The distribution of Mn and Ni in soils of one of the most famous winegrowing regions of Spain, Rioja D.O.Ca (Denomination of origin, Spain's top category), was studied in detail according to its geographical location. There were background concentrations of 288.81 mg kg^?1 total Mn in the surface horizon and 296.06 mg kg^?1 in the subsoil; and a total Ni content of 17.89 mg kg^?1 in the surface horizon and 24.76 mg kg^?1 in the subsoil. The amounts of Mn bio- or phytoavailable were 5.28 mg kg^?1 in the upper horizon and 4.70 mg kg^?1 in the subsurface horizon; and for Ni bio- or phytoavailable, the amounts were 0.14 mg kg^?1 in the upper horizon and 0.13 mg kg^?1 in the deeper horizon. Spatial distribution patterns were established using GIS contour maps for the two elements, showing significant variations within and between the sites. The local contamination is generally associated with the quantities that are added to the soil or water from man-made sources such as industrial discharge and volatile emissions, sewage sludge, livestock wastes and other wastes.     

Isolation,identification and development of culture medium in the production of Chlorella vulgaris

Microalgae have gained importance as a potential component of conventional food. The aim of the present study was to study the behaviour of the microalga Chlorella vulgaris in relation to the different carbon and nitrogen sources and to improve a culture medium in terms of glucose, urea, manganese chloride and sodium nitrate concentrations. In the investigation of the best source of carbon and nitrogen, it was observed that 1.14 mg L^?1 of glucose and 8.32 mg L^?1 of urea stood out with the production of 0.823 g L^?1 of dry biomass and yield of 52 mg L^?1 day^?1. The best growth rate and specific yield were achieved at the central points for all salts.     

Biomonitoring of maritime pollution by heavy metals (Pb and Zn) in the coast of Jijel (Algeria)

This paper reports a study of pollution in the coastal waters of Jijel, Algeria, using algae Ulva lactuca and Corallina officinalis as bioindicators. Samples of seawater and algae were collected at four different stations from the coast of Jijel, during the period of April–June 2014. The heavy metal content (Pb and Zn) was determined in seawater and in the algae tissue by the technique of atomic absorption spectrophotometry. In seawater, the contents of heavy metals vary from 0.017 to 0.03 mg/l (Pb) and 0.235 to 0.873 mg/l. In the algae tissues, metals concentrations vary between 1.88 to 6.25 μg g^?1 dry weight (Pb), and from 92 to 178.9 μg g^?1 dry weight (Zn). These levels differ by site and species. The calculation of the bioconcentration factor (BCF) leads us to conclude that algae bioaccumulate significant levels of Pb and Zn metals in their tissues. Our results shows that the species of C. officinalis bioaccumulate the metals Pb and Zn more than U. lactuca, where, high biosorption of Zn was observed with BCF values between 203.21 and 238.40. Zn content in seawater and algae tissues appear higher than standards set by USEPA and guides values of Certified Reference Materials, but Pb levels appear lower than this standard.     

Radioactive element contents of some granites used as building materials: insights into the radiological hazards

This study was conducted to investigate the radioactive potential hazard of granite, which is widely used as building material in Turkey. Natural radiation levels of 18 various, globally-distributed industrial granite samples imported by Turkey, were analyzed using gamma-ray spectrometer. The results are compared with the formerly published findings of granite samples from Turkey. Radioactivity levels of ²³⁸U, ²³²Th, and ⁴⁰K natural radioactive series elements of the selected 18 specimens were measured, which were from 2.4 ± 0.5 to 88.8 ± 3.6 Bq kg^?1 for ²³⁸U, from 2.4 ± 0.7 to 273 ± 0.9 Bq kg^?1 for ²³²Th, and from 169 ± 24 to 1,479 ± 94 Bq kg^?1 for ⁴⁰K. Radium equivalent activities (Ra_eq) were calculated for the granite samples to assess their radiation hazards in the construction of dwellings. The Ra_eq values of granite samples varied in the range of 39.05–570 Bq kg^?1, only one sample exceeded the safe limit value of 370 Bq kg^?1 set by the OECD-NEA (Nuclear Energy Agency. Exposure to radiation from natural radioactivity in building materials. Report by NEA Group of Experts 1979). Absorbed dose rates in air were found between 18.74 and 261 nGy h^?1 and radiogenic heat production values were calculated in the range of 0.45–6.53 μW m^?3. All rock samples used in this study were also analysed mineralogically and defined their compositions.     

Suspended timber ground floors: measured heat loss compared with models

ABSTRACT

There are approximately 6.6 million dwellings in the UK built before 1919, predominantly constructed with suspended timber ground floors whose thermal performance has not been extensively investigated. The results are presented from an in-situ heat-flow measuring campaign conducted at 27 locations on a suspended timber ground floor, and the estimated whole-floor U-value compared with modelled results. Findings highlight a significant variability in heat flow, with increased heat loss near the external perimeter. In-situ measured-point U-values ranged from 0.54?±?0.09?Wm^?2 K^?1, when away from the external wall perimeter, to nearly four times as high (2.04?±?0.21?Wm^?2 K^?1) when near the perimeter. The results highlight the fact that observing only a few measurements is likely to bias any attempts to derive a whole-floor U-value, which was estimated to be 1.04?±?0.12?Wm^?2 K^?1 and nearly twice that derived from current models. This raises questions about the validity of using such models in housing stock models to inform retrofit decision-making and space-heating-reduction interventions. If this disparity between models and measurements exists in the wider stock, a reappraisal of the performance of suspended timber ground floors and heat-loss-reduction potential through this element will be required to support the UK’s carbon-emission-reduction targets.     

Toxicity, uptake and survey studies of boron in the marine environment

Little is known about the toxic and bioaccumulative dangers to aquatic life posed by borate discharge recently initiated by coastal British Columbia groundwood pulp mills. Bioassays with sodium metaborate and underyearling coho salmon (Onchorhynchus kisutch) in fresh water yielded a 283-h lc₅₀ of 113 μg ml⁻¹ (104, 123 = 95% confidence limits). Toxicity to underyearling coho in sea water appeared considerably greater with a 283 h lc₅₀ of 12.2 μg ml⁻¹ (10.89, 14.56 = 95% confidence limits). The disparity between fresh and saltwater boron toxicity to coho is not understood at this time. In salmonids, boron enters the tissues slowly, necessitating prolonged bioassay tests. Sockeye salmon (O. nerka) and juvenile oysters (Crassostrea gigas) exposed to sublethal doses of boron take up boron roughly in relation to its availability. Oysters show no bioaccumulative potential or prolonged retention of boron following cessation of dosage. Field surveys conducted before and after industrial borate emission confirm the lack of evidence for tissue bioaccumulation. Results of a survey of boron levels in receiving waters are reported. No hazard to salmonids of oysters at the present level of industrial discharge of boron (≤1 μg B ml⁻¹) is apparent from this work.     

Effect of ammonium on the hydraulic conductivity of geosynthetic clay liners

Hydraulic conductivity and swell index tests were conducted on a conventional geosynthetic clay liner (GCL) containing sodium-bentonite (Na-B) using 5, 50, 100, 500, and 1000 mM ammonium acetate (NH₄OAc) solutions to investigate how NH₄⁺ accumulation in leachates in bioreactor and recirculation landfills may affect GCLs. Control tests were conducted with deionized (DI) water. Swell index of the Na-B was 27.7 mL/2 g in 5 mM NH₄⁺ solution and decreased to 5.0 mL/2 g in 1000 mM NH₄⁺ solution, whereas the swell index of Na-B in DI water was 28.0 mL/2 g. Hydraulic conductivity of the Na-B GCL to 5, 50, and 100 mM NH₄⁺ was low, ranging from 1.6–5.9 × 10^?11 m/s, which is comparable to the hydraulic conductivity to DI water (2.1 × 10^?11 m/s). Hydraulic conductivities of the Na-B GCL permeated with 500 and 1000 mM NH₄⁺ solutions were much higher (e.g., 1.6–5.2 × 10^?6 m/s) due to suppression of osmotic swelling. NH₄⁺ replaced native Na⁺, K⁺, Ca²⁺, and Mg²⁺ in the exchange complex of the Na-B during permeation with all NH₄⁺ solutions, with the NH₄⁺ fraction in the exchange complex increasing from 0.24 to 0.83 as the NH₄⁺ concentration increased from 5 to 1000 mM. A Na-B GCL specimen permeated with 1000 mM NH₄⁺ solution to chemical equilibrium was subsequently permeated with DI water. Permeation with the NH₄⁺ converted the Na-B to “NH₄-bentonite” with more than 80% of the exchange complex occupied by NH₄⁺. Hydraulic conductivity of this GCL specimen decreased from 5.9 × 10^?6 m/s to 2.9 × 10^?11 m/s during permeation with DI water, indicating that “NH₄-bentonite” can swell and have low hydraulic conductivity, and that the impact of more concentrated NH₄⁺ solutions on swelling and hydraulic conductivity is reversible.     

Contribution of domestic effluents to hydrocarbon levels of dry weather flow in combined sewers

The importance of hydrocarbon contamination of the sewer network has been reported by many authors recently. Most of the studies are focused on the introduction of such pollutants into combined sewers by street and roof stormwater, but few evaluate the contribution of domestic inputs to hydrocarbon pollution. As a consequence, this work—carried out on the framework of the OPUR (Observatory of Urban Pollutants) research program—assesses the resolved aliphatic (AH), unresolved complex mixture (UCM) and polycyclic aromatic hydrocarbon (PAH) concentrations of domestic effluents (DE) and evaluates the role played by such effluents on the hydrocarbon levels of dry weather flow (DWF) in combined sewers. Results show hydrocarbon concentrations in the 200 – 300 μg · l^?1, 300 – 1 000 μg · l^?1 and 0.9 – 1.4 μg · l^?1 ranges for AHs, UCM and the 16 PAHs of the US-EPA, respectively. The assessment of hydrocarbon fluxes conveyed by domestic effluents on the scale of the ‘Le Marais’ experimental urban catchment (42 ha, centre of Paris) reveals the predominant contribution of domestic inputs to the DWF pollution and highlights the unsuspected role of households.     

Complex assessment of toxicity,cyto-, and gentotoxicity of polyexamethyl guanidine concurrently with the use of plant and animal test-organisms and their cells

The paper presents the biotesting results of aqueous solutions of polyhexamethyl guanidine of grade Aquaton with a goal of investigating the impact of toxic, genotoxic, and cytotoxic influence of the compounds of the guanidine series on plant and animal test-organisms and their cells, i.e., assessments of their ecological safety. The given compound prepared on model and natural waters at the concentration 0.01 and 0.1 mg/dm³ causes toxic and genotoxic effects in animal and plant biotests and cellular biomakers. The concentration 0.01 mg/dm³ was an ecological safety boundary. The proposed complex approach concurrently using batteries of animal and plant test-organisms and their cells is an effective instrument for conducting a comprehensive analysis of recommended working and residual concentration of newly developed coagulants and flocculants.     

A decade’s (2014–2024) perspective on cassava’s (Manihot esculenta Crantz) contribution to the global hydrogen cyanide load in the environment

In recent years, developing countries have increased their cassava (Manihot esculenta) production for food security. Cassava contains cyanogen glycosides, mainly as linamarin, which through bio-catalysis, i.e. enzyme hydrolysis, results in hydrogen cyanide (HCN). HCN is released into the environment through numerous ways with subsequent volatilisation. Thus, the HCN released during the period 2002–2013 was estimated between 0.025?×?10^?3 to 6.71 ppq (African), 0.012?×?10^?3 to 1.01 ppq (Asian) and 0.007?×?10^?3 to 0.920?×?10^?3 ppq (South American). Furthermore, a decade’s (2014–2024) projection of HCN volatilisation displays increases of 60.5% (Africa), 57.7% (Asia) and 50.5% (South America) when compared with the current production. Furthermore, gas released during cassava plants’ growth, i.e. HCN, NH₃, and NO₂, was quantified in healthy plants. Varying concentrations of HCN were released. These further indicated the presence of a pseudo-halogenic gas in the environment – a contributor to climate change.     

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

This paper presents new proposals in the evaluation and determination of the optimum materials suitable for use in the design and development of firefighter protective clothing by simultaneously addressing the conflicting factors of thermal protection [heat transfer index (HTI), radiant heat transfer index (RHTI) and thermal threshold index (TTI)] and anti-heat stress [water vapor resistance (WVR) and total heat loss (THL)]. To achieve this, this paper proposes new indices for the materials, two types of “total performance” indices, which are defined as the sum and the product of the competing factors of thermal protection and anti-heat stress. The results showed that the candidate materials of firefighter protective clothing were easily rated when the new indices were applied. Of five candidate materials viz. A, B, B₁, B₂ and C, the B sample, with values for HTI₂₄?=?13.2?±?0.2 s, RHTI₂₄?=?18.0?±?0.8 s, TTI?=?1132?±?33 J/m², WVR?=?17.5?±?0.3 m² Pa/W and THL?=?266.2?±?4.1 W/m², was found to exhibit the best total performance. However, the methods proposed to the scientific community in this paper have so far been validated on a limited data set only, and will require further validation by a wider group of researchers and with more samples. Lastly, comments on ISO 11999-3:2015 were also made for the further improvement and development of technical standards.     

Impact of polyhexamethylene guanidine hydrochloride on the process of coagulation treatment of river waters

The paper has investigated flocculation capacity of polyhexamethylene guanidine hydrochloride during joint treatment with aluminum sulfate of the Dnieper and Desna River water in the spring period. It has been shown that additives 1–5 mg/dm³ of the matter under study during coagulation treatment of the river waters improves the process of their clarification, increases the filtrate quality in terms of main indicators and makes it possible to reduce by 10–20 mg/dm³ the dose of the coagulant. A pronounced flocculation effect manifests itself when treating the waters in question by the doses of a polymer preparation respectively 3–5 and 2–3 mg/dm³. Polyhexamethylene guanidine (without a coagulant) ensures a standardized quality of the filtrate in terms of color and turbidity only when treating weakly stained water of the Desna River. It has been found that ≥ 99% of polyhexamethylene guanidine is retained by the medium of a sand filter.     

Fire Performance of Phase Change Material Enhanced Plasterboard

Sustainable construction materials are increasingly being used to reduce the carbon footprint of modern buildings. These materials have the potential to change the fire dynamics of compartments by altering the compartment energy balance however there is little quantitative understanding of how these materials behave in the event of a real fire. The changes in fire dynamics may be due to increased fuel load in a compartment, reduced time to failure or promotion of flame spread. The objective of this research is to quantify how Phase Change Materials (PCMs) perform in realistic fire scenarios. It was found that a plasterboard product containing microencapsulated PCMs will behave similarly to a charring solid and have the potential to contribute significant fuel to a compartment fire but that they maintain integrity for the duration of flaming period. The critical heat flux for this product was determined in the cone calorimeter to be 17.5 ± 2.5 kW m^?2, the peak heat release rate and mass loss rate ranged from 60.2 kW m^?2 to 107 kW m^?2 and 1.88 g s^?1 m^?2 to 8.47 g s^?1 m^?2 respectively for exposures between 20 kW m^?2 and 70 kW m^?2. Sample orientation was found to increase the peak heat release rate by up to 25%, whilst having little to no effect on the mass loss rate. These parameters, in addition to the in-depth temperature evolution and ignition properties, can be used as design criteria for balancing energy savings with quantified fire performance.     

Concentrations and risks of polycyclic aromatic hydrocarbons in smoke-cured fish products in Nigeria

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smoked fish species, (Clarias gariepinus, Parachana obscura, Heterotis niloticus, Pseudotolithus senegalensis, Gymnarchus niloticus, Ethmalosa fimbriata, Sardinella aurita, Scromber scrombus and Trachurus trachurus), in the Nigerian market by using gas chromatography-mass spectrometry after extraction by ultrasonication with hexane/dichloromethane. The mean concentrations of ∑16 PAHs in these species ranged from 52.4 μg kg^?1 to 1230 μg kg^?1. The estimated margins of exposure (MOE values) were less than 10,000 for C. gariepinus, G. niloticus and E. fimbriata indicating serious concern for the consumers’ health. The estimated excess cancer risk factors for these fish species investigated indicate that approximately 1 to 65 out of 10⁶ equally exposed adults may suffer from cancer and cancer-related diseases during their lifetime through the ingestion of carcinogenic PAHs from smoked fish in their diet.