Environmental evaluation of hot water treatments to control Liriomyza huidobrensis infesting plant material in transit

Though quarantine disinfestation treatments have been exempt from the methyl bromide phase out, it is still required to research and develop alternative treatments for fumigation of plant material in transit. This study investigated the ability of both the egg and pupal stages of the quarantine pest, South Americian leafminer, Liriomyza huidobrensis to survive submersion in water heated to temperatures between 40 and 50 °C for varying periods of time. Large reductions in egg viability were recorded. However, the treatments also resulted in unacceptable levels of damage to the host plant material. Damage was uneconomically viable. Pupae were all killed exposure to water at 44 °C for 20 min. Incubation of insect and plant material at either 5 or 20 /dgC for 24 h before submersion in the hot water did not significantly alter the pests’ ability to survive the treatments. The potential of hot water treatments to act as an alternative to methyl bromide fumigation for disinfecting plants in transit is discussed.     

Leaf dipping as an environmental screening measure to test chemical efficacy against Bemisia tabaci on poinsettia plants

The screening of potential chemicals for control of Bemisia tabaci on poinsettia (Euphorbia pulcherrima c.v. Lilo Pink) plants using a leaf dipping technique was investigated. All relevant B. tabaci lifestages (eggs, larvae and adults) were investigated. In leaf dipping tests, Certis spraying oil was the only compound to show potential to be used as a control agent against B. tabaci eggs, with 81% obtained mortality. Oberon resulted in no mortality of B. tabaci eggs in the reported experiments. Leaf dipping against second instar and adult B. tabaci proved more effective for all chemical products. Dipping techniques using Majestik, Certis spraying oil and Agri- 50 E all resulted in high second instar larval mortality (93, 87 and 85.5 %, respectively). Certis spraying oil again resulted in a high efficacy against adult B. tabaci with 100 % mortality obtained. The potential of the various chemicals to be incorporated into integrated pest management strategies for the control of B. tabaci is discussed.     

Fluoride sorption and desorption on soils located in the surroundings of an aluminium smelter in Galicia (NW Spain)

Aluminium smelters are major sources of F emission to the environment. We studied, in laboratory experiments, the sorption and desorption of fluoride on organic and mineral horizons of soils located within 2 km from one of these factories, situated in the northern coast of Galicia (NW Spain). The soils, developed from granite, are acid (pH H₂O 3.9–5.5), rich in organic matter (4–16 % C in the A horizon) and most A horizons have high Al saturation in the exchange complex. All samples showed a notable F sorption, between 1,066 and 1,589 mg kg^?1, after adding 200 mg F L^?1, which accounts for 53–80 % of F added. The sorption was slightly higher in the A horizons than in the respective organic horizons (differences of up to 194 mg kg^?1). The fluoride sorption upon addition of 200 mg F L^?1 correlated significantly (p < 0.05) with soil pH in water (r = ?0.77), iron extracted by acid ammonium oxalate (r = 0.68), aluminium plus iron extracted by acid ammonium oxalate (r = 0.63), exchange aluminium (r = 0.52) and clay percentage in soil (r = 0.76). The F sorption fitted to both Langmuir and Freundlich models. Desorbed F accounted for only 12–22 % of sorbed fluoride and correlated (p < 0.05) negatively with non-crystalline (extracted by acid ammonium oxalate) Fe (r = ?0.51) and clay content (r = ?0.74) and positively with organic matter (r = 0.69) and with the effective cation exchange capacity of the soil (r = 0.50).     

Effect of empty bed residence time on biotrickling filter performance: case study—triethylamine

In this study, a laboratory-scale biotrickling filter (BTF) is used to remove Triethylamine (TEA) from gaseous wastes. The BTF is made of stainless steel with a height of 210 cm and an internal diameter of 21 cm packed with lava rocks. TEA elimination pattern was evaluated by changing empty bed residence times (EBRTs). The maximum elimination capacity (EC) has been determined to be 87 g/m³/h. At all EBRTs 52, 31, 20, and 10 s, contaminant transferring from gas phase to liquid was more than the EC. Also, the removal efficiency was 100 % for a mass loading of 100 g/m³/h. While the liquid recirculation velocity of 3.466 m³/m²/h was maintained, the flow rate was adjusted to 60, 100, 156, and 312 L/min. The results show that due to the high solubility of TEA in water for all the EBRTs, TEA can be solved in the circulated liquid and then be degraded gradually by microorganisms. Therefore, the least EBRT of 10 s is more appropriate.     

Effect of nitrogen addition on soil organic carbon in freshwater marsh of Northeast China

Increased nitrogen (N) input to ecosystems could alter soil organic carbon (C) dynamics, but the effect still remains uncertain. To better understand the effect of N addition on soil organic C in wetland ecosystems, a field experiment was conducted in a seasonally inundated freshwater marsh, the Sanjiang Plain, Northeast China. In this study, litter production, soil total organic C (TOC) concentration, microbial biomass C (MBC), organic C mineralization, metabolic quotient (qCO₂) and mineralization quotient (qmC) in 0–15 cm depth were investigated after four consecutive years of N addition at four rates (CK, 0 g N m^?2 year^?1; low, 6 g N m^?2 year^?1; moderate, 12 g N m^?2 year^?1; high, 24 g N m^?2 year^?1). Four-year N addition increased litter production, and decreased soil organic C mineralization. In addition, soil TOC concentration and MBC generally increased at low and moderate N addition levels, but declined at high N addition level, whereas soil qCO₂ and qmC showed a reverse trend. These results suggest that short-term N addition alters soil organic C dynamics in seasonally inundated freshwater marshes of Northeast China, and the effects vary with N fertilization rates.     

Biosorption of fluoride by water lettuce (<Emphasis Type="Italic">Pistia stratiotes</Emphasis>) from contaminated water

Phytoremediation is a proven low-cost and sustainable method for the removal of toxic pollutants from water. This green technology has been practiced for the past several years all over the world. In the present study, the interaction of fluoride on the surface of the floating aquatic plant water lettuce (Pistia stratiotes) during fluoride removal was investigated. Batch kinetic studies were performed to examine the fluoride uptake capacity of the plant with different initial fluoride concentrations such as 3, 5, 10, and 20 mg/L. The effects of various process parameters on fluoride uptake dynamics such as pH, plant biomass, initial fluoride concentration, and time were examined. Freundlich’s isotherm model was found to (R ² = 0.957) fit well to the experimental data. The nature of reaction order followed pseudo-first-order kinetics, when the initial fluoride level in the solution was 5 mg/L. The experimental findings showed that the removal mechanism was driven by biosorption phenomenon. High fluoride concentration in the solution reduced the growth ratio of P. stratiotes. The lowest growth ratio of this aquatic macrophyte was found to be 76.80 ± 3.73% at 20 mg/L fluoride concentration. At lower fluoride concentrations such as 3 and 5 mg/L, the growth ratio of the plant was not reduced significantly.     

Parascandolaite,KMgF3, a new perovskite-type fluoride from Vesuvius

The new mineral parascandolaite, isotypic to cubic perovskites, space group Pm \(\overline{3}\) m (no. 221) is the natural analog of the synthetic fluoride KMgF₃ and is related to neighborite, NaMgF₃. It was found as a volcanic sublimate at Vesuvius volcano on 1944 eruption lava scoria, associated with opal, cerussite, mimetite, phoenicochroite and coulsellite. It occurs as transparent colorless to white cubic crystals up to 0.5 mm in length with vitreous luster. The density measured by flotation in a diiodomethane–toluene mixture is 3.11(1) g/cm³; that calculated from the empirical formula and single-crystal X-ray data is 3.123 g/cm³. The mineral is isotropic with n = 1.395(5) (580 nm). The six strongest reflections in the X-ray powder diffraction pattern are: [d _obs in Å(I)(h k l)] 2.001(100)(2 0 0), 2.831(83)(1 1 0), 2.311(78)(1 1 1), 1.415(56)(2 2 0), 1.633(35)(2 1 1) and 1.206(22)(3 1 1). The unit-cell parameter is a = 4.0032(9) Å. The structure was refined to a final R(F) = 0.0149 for 35 independent observed reflections [I > 2σ(I)]. The mineral is named after the Italian mineralogist Antonio Parascandola (1902–1977).     

Phosphorus biological cycle in the different Suaeda salsa marshes of the Yellow River estuary, China

Much uncertainty exists in the phosphorus (P) cycle in the marshes of the intertidal zone. This study explored the P cycling in the two Suaeda salsa marshes [middle S. salsa marsh (MSM) and low S. salsa marsh (LSM)] of the Yellow River estuary during April 2008 to November 2009. Results showed seasonal fluctuations and vertical distributions of P in different S. salsa marsh soils, and variations in P content in different parts of plants due to water and salinity status. The N/P ratios of the different S. salsa were 9.87 ± 1.23 and 15.73 ± 1.77, respectively, indicating that plant growth in MSM was limited by N, while that in LSM was limited by both N and P. The S. salsa litter in MSM released P to the environment throughout the year, while that in LSM immobilized P from the environment at all times. The P absorption coefficients of S. salsa in MSM and LSM were very low (0.0010 and 0.0001, respectively), while the biological cycle coefficients were high (0.739 and 0.812, respectively). The P turnovers among compartments of MSM and LSM showed that the uptake amounts of roots were 0.4275 and 0.0469 g m^?2 year^?1 and the values of aboveground parts were 1.1702 and 0.1833 g m^?2 year^?1, the re-translocation quantities from aboveground parts to roots were 0.8544 and 0.1452 g m^?2 year^?1, the translocation amounts from roots to soil were 0.0137 and 0.0012 g m^?2 year^?1, the translocation quantities from aboveground living bodies to litter were 0.3157 and 0.0381 g m^?2 year^?1, and the annual return quantities from litter to soil were less than 0.0626 and ?0.0728 g m^?2 year^?1 (minus represented immobilization), respectively. P was an important limiting factor in S. salsa marshes, especially in LSM. S. salsa was seemingly well adapted to the low-nutrient condition and the vulnerable habitat, and the nutrient enrichment due to the import of N and P from the Yellow River estuary would be a potential threat to the S. salsa marshes.     

Understanding Causes and Impacts of the Dinoflagellate, Cochlodinium polykrikoides, Blooms in the Chesapeake Bay

During August and September 2007, the lower Chesapeake Bay and its tributaries experienced a massive bloom of Cochlodinium polykrikoides Margalef (>10⁴ cells per milliliter) that persisted for over a month, was extremely patchy, and at times penetrated into the Atlantic Ocean. The onset of the bloom coincided with a period of intense rainfall and stormwater runoff after a protracted summer drought period. Genetic evidence showed this species to be distinct from many Asian strains but similar to other North American strains. Populations dominated by C. polykrikoides took up a variety of nitrogenous compounds to support their growth and were able to mobilize additional sources of organic nutrients through peptide hydrolysis. Bioassays determined that C. polykrikoides exerted a lethal affect on juvenile fish and shellfish, causing 100% mortality of juvenile fish (Cyprinodon variegates) in less than 24 h and 20% mortality in juvenile American oysters (~21 mm; Crassostrea virginica) within 72 h.     

Is filter packing important in a small-scale vermifiltration process of urban wastewater?

Nowadays, natural resources are under increasing stress which fosters wastewater reuse planning and emphasizes on the decentralized wastewater treatment. Vermifiltration has been described as a viable alternative to treat domestic and urban wastewater, but few studies have focused on the impact of different filter packings on vermifiltration performance. This study evaluates the effect of vermicompost and sawdust in a single-stage vermifilter (VF) for urban wastewater treatment. After an acclimation period of 45 days, urban wastewater from a combined sewage collection system was applied continuously for 24 h. Earthworm stock density was of 20 g L^?1, HRT of 6 h, HLR of 0.89 m³ m^?2 day^?1 and OLR of 7.38 g BOD₅ day^?1. System performance was assessed by the removal efficiencies of BOD₅, COD, TSS, NH₄ ⁺, TN and TP, and fecal coliforms and helminth eggs elimination. Vermicompost (VE) and sawdust (SE) were tested, using an earthworm abundance of 20 g L^?1. Treatment efficiencies were 91.3% for BOD₅, 87.6% for COD, 98.4% for TSS and 76.5% for NH₄ ⁺ in VE, and 90.5% for BOD₅, 79.7% for COD, 98.4% for TSS and 63.4% for NH₄ ⁺ in SE. Earthworms contributed to reduce NH₄ ⁺ and TN removal and to increase NO₃ ^? concentration. No treatment was able to eliminate fecal coliforms down to guidelines values for wastewater irrigation as helminth eggs were completely eliminated. Single-stage vermifiltration system using both filter packings is inconsistent and cannot meet EU guideline values for discharge in sensitive water bodies and WHO guidelines for irrigation with treated wastewater.     

Spatio-Temporal Patterns of Submerged Macrophytes in Three Hydrologically Altered Mediterranean Coastal Lagoons

Rice cultivation in the Ebro Delta (Catalonia, Spain) has inverted the natural hydrological cycles of coastal lagoons and decreased water salinities for over 150 years. Adjustments in the water management practices—in terms of source and amount of freshwater inputs—have resulted in changes in the diversity, distribution and productivity of submerged angiosperms. Between the 1970s and late 1980s, a massive decline of the aquatic vegetation occurred in the Encanyissada–Clot and Tancada lagoons, but little information on the status is available after the recovery of macrophytes in the 1990s. Here, we evaluate the influence of salinity regimes resulting from current water management practices on the composition, distribution, seasonal abundance and flowering rates of submersed macrophytes, as well as on the occurrence of epiphyte and drift macroalgae blooms in three coastal lagoons. Our results show that Ruppia cirrhosa is the dominant species in the Encanyissada lagoon (185.97?±?29.74 g?DW?m^?2?year^?1; 12–27?‰ salinity) and the only plant species found in the Tancada lagoon (53.26?±?10.94 g?DW?m²?year^?1; 16–28?‰ salinity). Flowering of R. cirrhosa (up to 1,011?±?121 flowers?m^?2) was only observed within the Encanyissada and suggests that mesohaline summer conditions may favor these events. In contrast, low salinities in Clot lagoon (～3–12?‰) favor the development of Potamogeton pectinatus (130.53?±?13.79 g?DW?m²?year^?1) with intersperse R. cirrhosa (8.58?±?1.71 g?DW?m^?2) and mixed stands of P. pectinatus and Najas marina (up to ～57 g?DW?m^?2?year^?1) in some reduced areas. The peak biomasses observed during the study are 88 to 95 % lower than maximum values reported in the literature at similar salinities, and there is also little or no recovery in some areas compared to last reports more than 20 years ago. The main management actions to restore the natural diversity and productivity of submersed angiosperms, such as the recovering of the seagrass Zostera noltii, should be the increase of salinity during the period of rice cultivation, by reducing freshwater inputs and increasing flushing connections with the bays.     

Toxinogenicity and cytotoxicity of <Emphasis Type="Italic">Alternaria,Aspergillus</Emphasis> and <Emphasis Type="Italic">Penicillium</Emphasis> moulds isolated from working environments

There is currently limited research available on the secondary metabolites of moulds in workplaces. The aim of this study was to determine the mould contamination in museums (N = 4), composting plants (N = 4) and tanneries (N = 4) and the secondary metabolite profiles of Alternaria, Aspergillus and Penicillium isolates from these workplaces. Alternaria, Aspergillus and Penicillium species were identified using the ITS1/2 sequence of the rDNA region. Mould metabolites were quantitatively analysed on standard laboratory medium and mineral medium containing materials specific to each workplace using liquid chromatography-mass spectrometry. We also examined the cytotoxicity of the moulds using MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assays. Air microbiological contamination analyses showed a number of microorganisms, ranging from 2.4 × 10³ CFU m^?3 (composting plants) to 6.8 × 10⁴ CFU m^?3 (tanneries). We identified high percentages of Alternaria, Aspergillus and Penicillium moulds (air 57–59%, surfaces 10–65%) in all workplaces. The following moulds were the most cytotoxic (>90%): Alternaria alternata, A. limoniasperae, Aspergillus flavus, Penicillium biourgeianum, P. commune and P. spinulosum. The same mould species isolated from different working environments exhibited varying toxigenic and cytotoxic properties. Modifying the culture medium to simulate environmental conditions most often resulted in the inhibition of secondary metabolite production. Moulds isolated from the working environments produced the following mycotoxins (ng g^?1): chanoclavines (0.28–204), cyclopiazonic acid (27.1–1045), fumigaclavines (0.33–10,640,000), meleagrin (0.57–13,393), roquefortins (0.01–16,660), rugulovasines (112–220), viridicatin (0.12–957), viridicatol (4.23–2753) and quinocitrinines (0.07–1104), which may have a negative impact on human health.     

Une méthode de quantification de la dégradation d'un escarpement de faille au cours des cycles climatiques du Quaternaire : la faille de Jobourg (Nord Cotentin,France)Quantification of a fault-scarp degradation through Quaternary: the Jobourg fault (North Cotentin,France)

The degradation of the Jobourg fault-scarp occurred by cryoclastic processes in a periglacial environment during a part of Quaternary time. An attempt of quantification indicates a bulk scarp erosion of about 39 m³ m^?2, while the head accumulated at the bottom of the fault scarp only represents 4.6 m³ m^?2. To cite this article: M. Font et al., C. R. Geoscience 334 (2002) 171–178.     

Determination of radon exhalation from granite, dolerite and marbles decorative stones of the Azad Kashmir area, Pakistan

Extensive export quality reserves of granite, dolerite and marbles which are used for interior decorations as wall facing, paving floors, kitchen counter tops, etc., are available in Azad Kashmir. Since these stones contain radium in trace amounts, therefore, its use as a building material may be a potential source of indoor radon. In order to assess health hazards due to the use of these stones as a building material, samples were collected from different mining sites. After processing, these samples were placed in plastic containers and box type radon detectors were installed in it at the height of 25 cm above the surface of the samples. The containers were then hermetically sealed. After 60 days of exposure to radon, CR-39 detectors were etched in 6 M NaOH at 70 °C for 9 h and measured track densities were related to radon concentration. Radon exhalation rate form the studied granites, marble and dolerite samples varied from 87 ± 26 to 353 ± 36 mBq m^?2h^?1, 79 ± 25 to 650 ± 42 mBq m^?2h^?1 and 90 ± 26 to 324 ± 36 mBq m^?2h^?1, respectively. These decorative stones are therefore used in buildings and for export purposes as the observed radon exhalation values are smaller than that of the EPA recommended-action level.     

Dynamics of carbon fluxes with responses to vegetation,meteorological and terrain factors in the south-eastern Tibetan Plateau

Tibetan Plateau (TP) is the highest and most extensive plateau in the world and has been known as the roof of the world, and it is sensitive to climate change. The researches of CO₂ fluxes (F _C) in the TP region play a significant role in understanding regional and global carbon balance and climate change. Eddy covariance flux measurements were conducted at three sites of south-eastern TP comprising Dali (DL, cropland ecosystem), LinZhi (LZ, alpine meadow ecosystem) and Wenjiang (WJ, cropland ecosystem); amongst those DL and LZ are located in plateau region, while WJ is in plain region. Dynamics of F _C and influences of vegetation, meteorological (air temperature, photosynthetically active radiation, soil temperature and soil water content) and terrain factors (altitude) were analysed on the basis of data taken during 2008. The results showed that, in the cool sub-season (March, April, October and December), carbon sink appeared even in December with fluxes of (?0.021 to ?0.05) mg CO₂ m^?2 s^?1 and carbon source only in October (0.03 ± 0.0048) mg CO₂ m^?2 s^?1 in DL and WJ site. In LZ site, carbon sink was observed in April: (?0.036 ± 0.0023) mg CO₂ m^?2 s^?1 and carbon sources in December and March (0.008–0.010 mg CO₂ m^?2 s^?1). In the hot sub-season (May–August), carbon source was observed only in May with (0.011 ± 0.0022), (0.104 ± 0.0029) and (0.036 ± 0.0017) fluxes in LZ, DL and WJ site, respectively, while carbon sinks with (?0.021 ± 0.0041), (?0.213 ± 0.0007) and (?0.110 ± 0.0015) mg CO₂ m^?2 s^?1 fluxes in LZ, DL, and WJ, respectively. Comparing with plain region (WJ), carbon sinks in plateau region (DL and LZ) lasted for a longer time, and the absorption sum was large and up to (–357.718 ± 0.0054) and (?371.111 ± 0.0039) g C m^?2 year^?1, respectively. The LZ site had the weakest carbon sink with (?178.547 ± 0.0070) g C m^?2 year^?1. Multivariate analysis of covariance showed that altitude (AL) as an independent factor explained 39.5 % of F _C (P < 0.026). F _C had a quadratic relationship with Normalized difference vegetation index (NDVI) (R ² ranges from 0.485 to 0.640 for three sites), an exponential relationship with soil temperature at 5-cm depth (ST ₅) at night time and a quadratic relationship with air temperature (T _a) at day time. Path analysis indicated that photosynthetically active radiation (PAR), sensible heat fluxes (H) and other factors all had direct or indirect effects on F _C in all of the three tested sites around the south-eastern TP.     

Fate and transport of ethanol-blended dissolved BTEX hydrocarbons: a quantitative tracing study of a sand tank experiment

To estimate the behavior of ethanol-blended dissolved BTEX hydrocarbons in groundwater, a quantitative tracing study instead of qualitative analysis was carried out by using a large sand tank, into which 2-L solution including bromide, ethanol and dissolved BTEX was injected under a controlled hydraulic condition. Mean residence time (MRT), pore volume swept by solute (V _p), retardation coefficient (R) and biodegradation rate constant (k) of injected solutes were estimated. Compared with bromide that was used as a conservative tracer, ethanol and BTEX had shorter MRT and smaller V _p with the sequence of EtOH < T < E < m/p-X < o-X < B < Br. Biodegradation was confirmed as evidenced by the consumptions of dissolved oxygen (DO), nitrate and sulfate, and the production of acetate. The sequence of k as EtOH > T > E > m/p-X > o-X > B was just opposite to the sequences of MRT and V _p. The relationship among above sequences implies that MRT and V _p can be used as indicators to assess in situ biodegradability of a solute. Biodegradation of a reactive solute can make its MRT shortened and V _p shrunk. In addition, the sorption of ethanol could be neglected (R = 1.0), whereas BTEX compounds were adsorbed (R = 1.04–1.15). It should be noted that biodegradation of a solute can affect the estimation of its retardation coefficient. To our knowledge, this paper provides an available route to quantitatively estimate biodegradability of a solute in groundwater.     

Toxicity of methyl parathion on growth and reproduction of three ecologically different tropical earthworms

This work illustrates the toxicological impact of pesticide methyl parathion (MP) (dust—2 % active ingredient, a.i.) on growth and reproduction performance in tropical earthworms: Metaphire posthuma (endogeic), Lampito mauritii (anecic) and Allolobophora parva (epigeic). A total of three concentrations (a.i. g kg^?1 dry test soil), 1.00 (T ₁), 1.125 (T ₂) and 2.25 (T ₃) of MP, were applied in test substrate to examine the impact on mortality, individual live weight changes and reproduction patterns in test species over 60 days under laboratory conditions. MP caused significant mortality in all tested species, and median lethal dose (LD₅₀) for L. mauritii, M. posthuma and A. parva was 24.85, 23.64 and 22.67 mg a.i., respectively. The individual live weight loss was 27.0–37.0 % in L. mauritii, 36.0–57.1 % in M. posthuma and 1.2–11.0 % in A. parva in different test concentrations. The pesticide-exposed worms produced less cocoons than control, but in L. mauritii, an unusual reproduction (hormesis) was recorded. Results suggested the species-specific toxicity of MP against tropical earthworms.     

Performance of activated carbon-impregnated cellulose filters for indoor VOCs and dust control

An activated carbon-impregnated cellulose filter was fabricated, and the capacity to remove dust and volatile organic compounds was evaluated in a laboratory. The adsorption capacities for benzene, toluene, ethyl benzene and m-xylene gases were compared by an adsorption isotherm test conducted as a preliminary test, showing that m-xylene and benzene were the most and least favorable for adsorption onto activated carbon, respectively. Cellulose filters were made with four levels of activated carbon contents, and dust removal was performed with all of the filters showing 99 % and higher efficiencies stable with a small variation during the experiment. Activated carbon content of 5 g in the unit filter area (125 g/m²) was found optimum for benzene, toluene, ethylbenzene and m-xylene removal, as it appeared that higher than 5 g activated carbon content was unnecessary for the improvement of its capacity. With increasing benzene, toluene, ethylbenzene and m-xylene loading, the highest removal rates were determined as 0.33–0.37 mg/cm² s for as short as 0.0046 s of air filter residence time. The rapid removal was possible because of the high surface area of the activated carbon-impregnated cellulose filter provided by powdered activated carbon, which is distinguished from the granular form in conventional activated carbon towers. As fixed within a cellulose scaffolding structure, the powdered activated carbon performed excellent benzene, toluene, ethylbenzene, and m-xylene adsorption (98.9–100 %), and at the same time, particular matters were removed in average 99.7 % efficiency after being filtered through the cellulose filter sheet.     

The Influence of Benthic Macrofauna on the Erodibility of Intertidal Sediments with Varying mud Content in Three New Zealand Estuaries

Fine sediment inputs can alter estuarine ecosystem structure and function. However, natural variations in the processes that regulate sediment transport make it difficult to predict their fate. In this study, sediments were sampled at different times (2011–2012) from 45 points across intertidal sandflat transects in three New Zealand estuaries (Whitford, Whangamata, and Kawhia) encompassing a wide range in mud (≤63 μm) content (0–56 %) and macrofaunal community structure. Using a core-based erosion measurement device (EROMES), we calculated three distinct measures of sediment erosion potential: erosion threshold (? _c ; N m^?2), erosion rate (ER; g m^?2 s^?1), and change in erosion rate with increasing bed shear stress (m _e ; g N^?1 s^?1). Collectively, these measures characterized surface (? _c and ER) and sub-surface (m _e ) erosion. Benthic macrofauna were grouped by functional traits (size and motility) and data pooled across estuaries to determine relationships between abiotic (mud content, mean grain size) and biotic (benthic macrofauna, microbial biomass) variables and erosion measures. Results indicated that small bioturbating macrofauna (predominantly freely motile species <5 mm in size) destabilized surface sediments, explaining 23 % of the variation in ? _c (p ≤ 0.01) and 59 % of the variation in ER (p ≤ 0.01). Alternatively, mud content and mean grain size cumulatively explained 61 % of the variation in m _e (p ≤ 0.01), where increasing mud and grain size stabilized sub-surface sediments. These results highlight that the importance of biotic and abiotic predictors vary with erosion stage and that functional group classifications are a useful way to determine the impact of benthic macrofauna on sediment erodibility across communities with different species composition.     

Chemical oxidation of N,N-diethyl-m-toluamide by sulfate radical-based oxidation: kinetics and mechanism of degradation

A study was undertaken in order to understand the kinetics and mechanism of the chemical oxidation of N,N-diethyl-m-toluamide, an insect repellent, by sulfate radical. In this experiment, sulfate radical was generated using peroxymonosulfate with iron(II) and cobalt(II) as activator. The second-order rate constant for the reaction of the sulfate radical with N,N-diethyl-m-toluamide was found to be (1.9 ± 0.1) × 10⁹ M^?1 s^?1 at pH 7 and a temperature of 25 °C. Experiments for the chemical oxidation of N,N-diethyl-m-toluamide in river water and secondary wastewater revealed that the percentage of the removal of N,N-diethyl-m-toluamide was slightly influenced by the water matrices. However, the selected oxidation systems are not effective for the removal of N,N-diethyl-m-toluamide in seawater. Transformation by-products of N,N-diethyl-m-toluamide generated using peroxymonosulfate/iron(II) sulfate, peroxymonosulfate/iron(II) chloride, peroxymonosulfate/cobalt(II) sulfate and peroxymonosulfate/cobalt(II) chloride systems were identified. The results indicated that there are slight differences in the distributions of the transformation by-products detected depending on the activator. The common transformation by-products detected in all selected oxidation systems are N,N-diethylbenzamide, N-ethyl-m-toluamide, N,N-dimethyl-m-toluamide, N-ethyl-N-acetyl-m-toluamide, 2-(diethylamino)-1-m-tolylethanone, monohydroxylated N-ethyl-m-toluamide, and dihydroxylated N,N-diethyl-m-toluamide. Monohydroxylated N,N-diethyl-m-toluamide were detected only when the peroxymonosulfate/iron(II) system was applied. For the peroxymonosulfate/cobalt(II) systems, additional isomers of monohydroxylated N-ethyl-m-toluamide were detected. Peroxymonosulfate/cobalt(II) also transformed 2-(diethylamino)-1-m-tolylethanone into N-ethyl-N-(2-oxo-2-m-tolylethyl)acetamide and monohydroxylated 2-(ethyl(vinyl)amino)-1-m-tolylethanone as transformation by-products.