Temperature effects on the toxicity of four trace metals to adult spotted Babylonia snails (Babylonia areolata)

A study was conducted to determine the median lethal toxicity of four heavy metals on the marine gastropod Babylonia areolata. Median lethal toxicity tests were conducted to observe the sensitivity of this gastropod to metals and how variations in temperature might affect toxicity of test elements. Four heavy metals were used in the study. It was observed that the 96-hr LC₅₀ (in mg/L) for the different metals was found to be nickel (Ni) 33.53 (35.22–28.43), copper (Cu) 44.59 (46.43–41.53), cadmium (Cd) 21.53 (23.43–18.37), and zinc (Zn) 27.34 (28.81–24.24) at room temperature 24 °C. With temperature as a variable, median lethal concentration (LC₅₀) values were observed to increase from 22.41 mg/L at 10 °C to 27.34 mg/L at 28 °C and reduce to 18.43 mg/L at 30 °C and a further rise in toxicity was observed at 35 °C where LC₅₀ value was 12.7 mg/L as seen in the case of Zn. It was also observed that at 40 °C thermal and chemical toxicity overlapped as 100% mortality was observed in controls. This trend was noted in all metals for Babylonia areolata indicating that temperature played an important role in determining LC₅₀ values of toxicants.     

Research on low emission MSW gasification and melting system

In order to eliminate secondary pollution caused by municipal solid waste (MSW) incineration, a MSW gasification and melting process is proposed. The process is expected to reduce the emission of pollutants, especially heavy-metals and dioxins. In this paper, the combustible components of MSW and simulated MSW were gasified in a lab-scale fluidized bed at 400°C–700°C when the excess air ratio (ER) was between 0.2 and 0.8. The experimental results indicated that the MSW could be gasified effectively in a fluidized bed at approximately 600°C–700°C when excess air ratio was 0.2–0.4. The melting characteristics of two typical fly ash samples from MSW incinerators were investigated. The results indicated that fly ash of pure MSW incineration could be melted at approximately 1,300°C and that of MSW and coal co-combustion could be melted at approximately 1,400°C. When temperature was over 1,100°C, more than 99.9% of the dioxins could be decomposed and most of the heavy-metals could be solidified in the slag. Based on the above experiments, two feasible MSW gasification and melting processes were proposed for low calorific value MSW: (1) sieved MSW gasification and melting system, which was based on an idea of multi-recycle; (2) gasification and melting scheme of MSW adding coal as assistant fuel.     

Sorption of phenanthrene to biochar modified by base

Biochar (BC) is a potential material for removal of polycyclic aromatic hydrocarbons from soil and water, and base modification is a promising method for improving its sorption ability. In this study, we synthesized a series of base-modified biochars, and evaluated their sorption of phenanthrene. Original biochars were produced by pyrolysis of three feedstocks (rice straw, wood and bamboo) at five temperatures (300°C, 350°C, 400°C, 500°C and 700°C). Base-modified biochars were further obtained by washing of biochars with base solution. The base soluble carbon (SC) was extracted from the supernatant, which were only obtained from biochars pyrolyzed at low temperatures (<500°C) and the content was decreased with the increase of pyrolysis temperature. The SC content between different feedstocks followed the trend of rice straw>wood>bamboo when same pyrolysis conditions were applied. It was found that base modification improved the sorption of phenanthrene on biochars that SC could be extracted from (extractable-BCs). However, base treatment but had limited effects for biochars that no SC could be extracted from. It suggested that base modification improved the sorption of phenanthrene to extractable-BCs by removing the SC and thus increasing the surface area and hydrophobicity. Therefore, base modification was suggested to be used in modifying extractable-BCs.

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Elevated temperature elicits greater effects than decreased pH on the development, feeding and metabolism of northern shrimp (Pandalus borealis) larvae

Climate models predict that the average temperature in the North Sea could increase 3–5 °C and surface-waters pH could decrease 0.3–0.5 pH units by the end of this century. Consequently, we investigated the combined effect of decreased pH (control pH 8.1; decreased pH 7.6) and temperature (control 6.7 °C; elevated 9.5 °C) on the hatching timing and success, and the zoeal development, survival, feeding, respiration and growth (up to stage IV zoea) of the northern shrimp, Pandalus borealis. At elevated temperature, embryos hatched 3 days earlier, but experienced 2–4 % reduced survival. Larvae developed 9 days faster until stage IV zoea under elevated temperature and exhibited an increase in metabolic rates (ca 20 %) and an increase in feeding rates (ca 15–20 %). Decreased pH increased the development time, but only at the low temperature. We conclude that warming will likely exert a greater effect on shrimp larval development than ocean acidification manifesting itself as accelerated developmental rates with greater maintenance costs and decreased recruitment in terms of number and size.     

Laboratory growth and metabolism of the winter flounder Pseudopleuronectes americanus from hatching through metamorphosis at three temperatures

Growth and metabolism of the winter flounder Pseudopleuronectes americanus were studied in the laboratory at 2°, 5° and 8°C. Dry-weight determinations of growth demonstrated significant direct regressions of growth on temperature. Mean, daily specific growth rates were 10.1%/day at 80°C, 5.8%/day at 50°C, and 2.6%/day at 2°C. Time to metamorphosis was 49 days at 8°C and 80 days at 5°C. Larvae did not survive to metamorphosis at 2°C. Absolute values of routine metabolism expressed in μl of oxygen consumed regressed on body weight were best described by a third-degree polynomial. Larval routine metabolism increased from hatching to metamorphosis, at which time it declined before again increasing. Temperature directly affected routine metabolism. Metabolism on a unit-weight basis decreased with increasing size and was also directly influenced by temperature.     

Resistenzadaptation bei gehemmeter Proteinbiosynthese. Versuche mit Actinomycin D an dem Fisch Rhodeus amarus

Rhodeus amarus acclimated to 10° or 20°C die at 31.7° or 36.4°C, respectively (cessation of operculum movements). After raising the adaptation temperature (AT) from 10° to 20°C, adaptation is complete after 8 days. The toxicity of actinomycin D, injected intraperitoneally, is AT-dependent (e.g. at 5°C, LD_{50–7 days}=0.8 μg/g fish; at 25°C, LD_{50–7 days}=0.35 μg/g fish). In the following experiments 0.5 μg actinomycin/g fish were used. After actinomycin-injection, RNA-values in white dorsal muscle decreased about 50% within 12 h and the values of control individuals were finally attained after 16 days. Following an AT-change from 10° to 20°C, DNA-values in the white dorsal muscle increased about 10%, RNA-values about 30%, within 12 h. However, in fish injected intraperitoneally with actinomycin, no increase in DNA or RNA was noticed. Actinomycin injection per se causes increased heat resistance. This process lasts 10 days. If AT is raised now from 10° to 20°C, the new resistance level is reached later. The control fish gain resistance at a rate of about 1 C°/day during the first days after the temperature change. Actinomycin-treated individuals, however, exhibit an increase of 0.25 C°/day. Inhibition of resistance adaptation due to proteinbiosynthesis-inhibitors supports the view that protein synthesis is of importance for adjustments in heat resistance of intact animals.

     

Calanoid copepod eggs in sea-bottom muds. III. Effects of temperature,salinity and other factors on the hatching of resting eggs of Tortanus forcipatus

The “resting” eggs of a marine neritic copepod, Tortanus forcipatus Giesbrecht, recovered from sea-bottom sediment were hatched in the laboratory. Hatching occurred at temperatures of 13° to 30°C, no eggs hatched at 10°C. Temperatures around 25°C were found to be optimal for hatching, although the range of optimal temperatures for hatching was approximately 5°C lower in eggs stored for 14 to 15 months than in those stored for 1 to 2 months. A wide range of salinity, from 18 to 54%S, was favourable for hachting. Eggs failed to hatch within the sediment mud, which suggests that they are in a state of dormancy in the mud. Hatching was successful under both light and dark conditions.     

Temporal limitations in the use of potassium dichromate as a blood preservative for the analysis of organohalogenated contaminants including polybrominated diphenyl ethers,dioxins and PCBs

Previous studies described the use of potassium dichromate (K₂Cr₂O₇) to successfully preserve whole blood for up to 34 days at room temperature (20–22°C) for analysis of chlorinated dioxins, dibenzofurans and PCBs. Potassium dichromate has been successfully employed as a preservative for cows’ milk and in a World Health Organization study of human milk. The use of two 100?mg tablets in 40 to 100?mL of whole blood in anticoagulant was found to provide almost identical levels of dioxins, dibenzofurans, PCBs and lipids as found in frozen comparison blood at??70°C which is generally regarded as the gold standard for blood preservation. Potassium dichromate was found to be preferable to 20 and 40% ethyl alcohol for this preservation. This finding opens opportunities for preservation under field conditions in developing countries where neither electricity nor dry ice is available. Not having to use dry ice for shipping also allows more flexibility in the choice of commercial carriers for transporting blood to an analytical laboratory. It is recommended considering a number of compounds in addition to those studied in our first report and extending the time beyond 34 days in order to determine if longer storage might also be feasible. Data on polybrominated diphenyl ethers (PBDEs), as well as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and selected polychlorinated biphenyls (PCBs) are reported. For the present study 3 and 6 months were chosen in potassium dichromate at room temperature compared to freezing at ?70°C. Data indicate that these times exceed the limits of efficacy of potassium dichromate for whole blood preservation. This was attributed to degradation of the lipid component of the blood. Since dioxins and closely related structural analogues are traditionally reported as lipid normalized blood levels, this degradation of lipids provides erroneous results. Therefore, potassium dichromate is not recommended for long-term storage beyond 34 days at room temperature. It is planned to study the time period between one and three months and higher temperature preservation for shorter time periods, simulating conditions in tropical countries, to attempt to extend further the ease and convenience of chemical preservation of blood.     

Impacts of near future sea surface pH and temperature conditions on fertilisation and embryonic development in Centrostephanus rodgersii from northern New Zealand and northern New South Wales, Australia

Oceans are warming and becoming more acidic. While higher temperature and lower pH can have negative effects on fertilisation and development of marine invertebrates, warming may partially ameliorate the negative effect of lower pH. This study determined the effect of warming (3 °C) and decreased pH (0.3, 0.5, 1.1 units below ambient) on fertilisation and development in two populations of the sea urchin Centrostephanus rodgersii, one at its northern range limit (Coffs Harbour, New South Wales NSW, 30°27′S, 153°14′E) and the other one in New Zealand where the species may be a recent arrival (Mokohinau Islands, 35°56′S, 175°9′E). Both populations were sampled in August 2011. The two populations exhibited a differential response to temperature, while pH affected them similarly. Fertilisation was robust to pH levels forecast for 2100, and it was only slightly reduced at pH values forecast for 2300 (i.e. ≈5 and ≈8 % for the northern NSW and the New Zealand populations, respectively). Decreased pH (pH = 7.6) reduced the percentage of succeeding developmental stages. Progression through cleavage and hatching stages was faster at +3 °C in the New Zealand population but not in northern NSW urchins, while for the NSW population, there was a positive interaction between temperature and pH at hatching. Gastrulation was negatively affected by an extreme pH 7.0 treatment (60–80 % reduction) and least affected by increased temperature. The percentage of abnormal embryos at gastrulation increased significantly at +3 °C treatment in the northern NSW population. Predicted future increases in temperature may facilitate further expansion of the geographical range of C. rodgersii in New Zealand, with a minimal effect of concurrent reduced pH.     

The synergistic effects of increasing temperature and CO2 levels on activity capacity and acid–base balance in the spider crab, Hyas araneus

With global climate change, ocean warming and acidification occur concomitantly. In this study, we tested the hypothesis that increasing CO₂ levels affect the acid–base balance and reduce the activity capacity of the Arctic spider crab Hyas araneus, especially at the limits of thermal tolerance. Crabs were acclimated to projected oceanic CO₂ levels for 12 days (today: 380, towards the year 2100: 750 and 1,120 and beyond: 3,000 μatm) and at two temperatures (1 and 4 °C). Effects of these treatments on the righting response (RR) were determined (1) at acclimation temperatures followed by (2) righting when exposed to an additional acute (15 min) heat stress at 12 °C. Prior to (resting) and after the consecutive stresses of combined righting activity and heat exposure, acid–base status and lactate contents were measured in the haemolymph. Under resting conditions, CO₂ caused a decrease in haemolymph pH and an increase in oxygen partial pressure. Despite some buffering via an accumulation of bicarbonate, the extracellular acidosis remained uncompensated at 1 °C, a trend exacerbated when animals were acclimated to 4 °C. The additional combined exposure to activity and heat had only a slight effect on blood gas and acid–base status. Righting activity in all crabs incubated at 1 and 4 °C was unaffected by elevated CO₂ levels or acute heat stress but was significantly reduced when both stressors acted synergistically. This impact was much stronger in the group acclimated at 1 °C where some individuals acclimated to high CO₂ levels stopped responding. Lactate only accumulated in the haemolymph after combined righting and heat stress. In the group acclimated to 1 °C, lactate content was highest under normocapnia and lowest at the highest CO₂ level in line with the finding that RR was largely reduced. In crabs acclimated to 4 °C, the RR was less affected by CO₂ such that activity caused lactate to increase with rising CO₂ levels. In line with the concept of oxygen and capacity limited thermal tolerance, all animals exposed to temperature extremes displayed a reduction in scope for performance, a trend exacerbated by increasing CO₂ levels. Additionally, the differences seen between cold- and warm-acclimated H. araneus after heat stress indicate that a small shift to higher acclimation temperatures also alleviates the response to temperature extremes, indicating a shift in the thermal tolerance window which reduces susceptibility to additional CO₂ exposure.     

Effect of light and temperature on the population dynamics of two toxic bloom forming Cyanobacteria – Microcystis ichthyoblabe and Anabaena aphanizomenoides

The effect of light and temperature on the growth of Microcystis ichthyoblabe and Anabaena aphanizomenoides, isolated from the subtropical Oued Mellah lake, Morocco (33°30′N–07°20′W), were investigated in batch culture. Growth rates at 66 light–temperature combinations were determined and fitted with different mathematical models. The results show that the two Cyanobacteria grow at all light intensities and temperatures, except at 10 °C for A. aphanizomenoides, where the growth was strongly limited. The μ_max of M. ichthyoblabe increased with temperature from 0.56 d^?1 at 10 °C to 1.32 d^?1 at 35 °C. At all tested temperatures, a relative photoinhibition within the studied range of irradiance was observed and the photosensitivity was thermodependent. For Anabaena, the obtained μ_max ranged between 0.07 d^?1 at 10 °C and 1.46 d^?1 at 35 °C, and a weak photoinhibition was observed at 15 °C. The positive correlation between μ_max and I_opt (r²≥0.93) indicates a close interaction between light and temperature on the cyanobacteria growth. The results obtained in this work suggest that the growth of these two species is possible under low light and low temperature.     

Catalytic hydrolysis of gaseous HCN over Cu–Ni/γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst: parameters and conditions

To decompose efficiently hydrogen cyanide (HCN) in exhaust gas, g-Al₂O₃-supported bimetallicbased Cu–Ni catalyst was prepared by incipient-wetness impregnation method. The effects of the calcination temperature, H₂O/HCN volume ratio, reaction temperature, and the presence of CO or O₂ on the HCN removal efficiency on the Cu–Ni/g-Al₂O₃ catalyst were investigated. To examine further the efficiency of HCN hydrolysis, degradation products were analyzed. The results indicate that the HCN removal efficiency increases and then decreases with increasing calcination temperature and H₂O/HCN volume ratio. On catalyst calcined at 400°C, the efficiency reaches a maximum close to 99% at 480 min at a H₂O/HCN volume ratio of 150. The HCN removal efficiency increases with increasing reaction temperature within the range of 100°C–500°C and reaches a maximum at 500°C. This trend may be attributed to the endothermicity of HCN hydrolysis; increasing the temperature favors HCN hydrolysis. However, the removal efficiencies increases very few at 500°C compared with that at 400°C. To conserve energy in industrial operations, 400°C is deemed as the optimal reaction temperature. The presence of CO facilitates HCN hydrolysis andincreases NH₃ production. O₂ substantially increases the HCN removal efficiency and NO _x production but decreases NH₃ production.

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Winter quiescence and spring awakening of the Eastern oyster Crassostrea virginica at its northernmost distribution limit

To test the hypothesis that oysters, Crassostrea virginica, from the northernmost part of the species range in the Gulf of St. Lawrence (48°N) open their valves at lower temperatures than those reported for more southern oysters, Hall element sensors were used to monitor their gaping behaviour. These observations were made in a flow-through system and the temperature, salinity and relative fluorescence of unfiltered seawater were monitored. Photoperiod was controlled (15?h dark:9?h light) and light levels were measured but not closely controlled. Gaping behaviour was followed from February to June 2010 (113?days) and from April to May 2011 (34?days) and was classified into three successive phases: quiescent, awakening and active. Although valves were either closed or slightly open during the quiescent phase (maximum gape angle?=?0.49°, SE?=?0.04), they abruptly opened to maximum angles of about 5.88° (SE?=?0.29) during the awakening phase. Moreover, there was noticeable synchrony amongst individuals, since approximately one-half of the monitored population awoke within a 6.6-h period in both study years. Correlative analyses identified temperature as a factor influencing valve movement, and oysters awakened when temperatures were 0.2–4.0?°C (mean?=?2.2, SE?=?0.2). Oysters exerted their maximal gape angle as soon as temperatures reached 2.8–6.6?°C (mean?=?4.8, SE?=?0.2). During the active phase, valves remained open 68.6?% (2010) and 79.7?% (2011) of the time. An unexpected result was the observation of a diurnal rhythm in valve openness whereby the openness was greatest near the end of the afternoon and least in the early morning.     

Cryopreservation of the dinoflagellate symbiont of the octocoral <Emphasis Type="Italic">Pseudopterogorgia elisabethae</Emphasis>

In this paper we describe a cryopreservation protocol followed by the culture of Symbiodinium sp. isolated from the Caribbean gorgonian Pseudopterogorgia elisabethae as a potential renewable source of the dinoflagellate symbiont. Four different freezing protocols were designed: a controlled cooling device designed to cool at 1°C/min, a three-step protocol (−20°C for 2 h, −70°C for 2 h, liquid nitrogen-LN₂), a two-step protocol (−70°C for 2 h, LN₂), and a one-step protocol (LN₂). All cells were stored in LN₂ after cryopreservation. The cryoprotective agents (CPA) used were ethanol (EtOH) and methanol (MeOH) at 10 and 20%, and seawater (FSW) was used as a control. Viability measurements using cell counts showed that all cryopreservation protocols were relatively successful, and no trends were observed regarding freezing protocol or CPA used. After 19 weeks in culture the viability of samples which had high biomass was determined by the fluorescent assay CellTiter Blue™. The most viable cultures were those cryopreserved by a two-step protocol using 20% MeOH or 20% EtOH as a CPA. A genetic examination of the DNA of these samples using Symbiodinium-specific PCR primers confirmed that the composition of the culture had not changed. For the first time, we report that Symbiodinium sp. isolated from a gorgonian can be cryopreserved and subsequently cultured successfully. Lory Z. Santiago-Vázquez and Nealie C. Newberger contributed equally to this publication.     

Degradation profile of azoxystrobin in Andisol soil: laboratory incubation

The fate of azoxystrobin in soil under the effect of different temperature is of interest because application directions specify soil-surface treatments for number of agricultural pests. Temperature is an important factor governing the rate of degradation in soil pore. The purpose of this investigation was to understand better the effect of temperature on the degradation of azoxystrobin in Japanese Andisol soil. This was done through laboratory incubation of soil at three different temperatures (5 °C, 20 °C, 35 °C). First-order kinetics could be used to describe degradation of azoxystrobin under controlled condition of temperature (r² ? 94). The results showed that, during the 120-day incubation period for azoxystrobin, 64%, 70%, and 78% of applied azoxystrobin were degraded at 5 °C, 20 °C, and 35 °C, respectively. By using the Arrhenius equation, the activation energy of degradation of azoxystrobin fungicide was calculated (7.48 ± 1.74 kJ mol^?1) in soils, which confirm that temperature had a significant influence on the degradation rate. Q₁₀ value of 1.11, for azoxystrobin, indicated that the response of fungicide dissipation to temperature was large. For azoxystrobin, there was a much larger difference in dissipation rates at 5 °C and 35 °C, indicating that biological and/or chemical degradation of azoxystrobin may have nearly reached its optimum at 35 °C.     

Thermal tolerance of early development in tropical and temperate sea urchins: inferences for the tropicalization of eastern Australia

The thermal envelope of development to the larval stage of two echinoids from eastern Australia was characterized to determine whether they fill their potential latitudinal ranges as indicated by tolerance limits. The tropical sand dollar, Arachnoides placenta, a species that is not known to have shifted its range, was investigated in Townsville, northern Australia (19°20′S, 146°77′E), during its autumn spawning season (May 2012). The subtropical/temperate sea urchin, Centrostephanus rodgersii, a species that has undergone poleward range expansion, was investigated in Sydney, southern Australia (33°58′S, 151°14′E), during its winter spawning season (August 2012). The thermal tolerance of development was determined in embryos and larvae reared at twelve temperatures. For A. placenta, the ambient water temperature near Townsville and experimental control were 24 °C and treatments ranged from 14 to 37 °C. For C. rodgersii, ambient Sydney water temperature and experimental control were 17 °C, and the treatment range was 9–31 °C. A. placenta had a broader developmental thermal envelope (14 °C range 17–31 °C) than C. rodgersii (9 °C range 13–22 °C). Both species developed successfully at temperatures well below ambient, suggesting that cooler water is not a barrier to poleward migration for either species. Both species presently live near the upper thermal limits for larval development, and future ocean warming could lead to contractions of their northern range limits. This study provides insights into the factors influencing the realized and potential distribution of planktonic life stages and changes to adult distribution in response to global change.     

Effects of ambient temperature on regulated gaseous and particulate emissions from gasoline-, E10- and M15-fueled vehicles

• Emissions from two sedans were tested with gasoline, E10 and M15 at 30°C and -7°C. • As the temperature decreased, the PM, PN and BC emissions increased with all fuels. • Particulate emissions with E10 and M15 were more sensitive to the temperature. • The PN and BC generated during cold start-up dominated those over the WLTC. Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and -7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%-79.4% at -7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at -7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at -7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.     

Effects of adding biochar on tetracycline removal during anaerobic composting of swine manure

Residual antibiotics in manure pose a potential threat to public and ecological health when the manure is released to the environment via land application of manure as fertiliser. Anaerobic composting has the potential to decrease antibiotic concentrations prior to land application. We therefore investigated the degradation of the antibiotics tetracycline (TC) and oxytetracycline (OTC) during anaerobic composting under different conditions. All composting treatment conditions were able to effect significant decreases in the antibiotic concentrations, though without biochar antibiotic residues remained. TC and OTC were removed more efficiently when the compost was treated at 55°C than treatments at 35°C or 25°C. Adding biochar significantly and rapidly decreased the antibiotic concentrations in the compost samples. After 15 days of treatment with biochar at 55°C, 100% of TC and OTC had been removed from the manure. The marked ability of biochar to remove the antibiotics was primarily attributed to adsorption of TC and OTC by the biochar. However, the addition of biochar may also have altered the microbial community structures within the compost and accelerated microbial degradation of the antibiotics.     

Optimization of process parameters of extraction of lotaustralin from the roots of Rhodiola rosea L using supercritical CO2 plus modifier

Lotaustralin from the root of Rhodiola rosea L was extracted using supercritical carbon dioxide with methanol as modifier. Response surface methodology using Box–Behnken experimental design was utilized to explore parameters for supercritical carbon dioxide extraction. The effects of various values of temperatures (50–70 °C), pressures (200--400 bar), and percentages of methanol modifier (80%–100%) on the extraction yields of lotaustralin were evaluated. Extract identification was performed using high-performance liquid chromatography. The experimental data obtained were fitted to second-order polynomial equations and assessed using analysis of variance. The highest yields predicted from the experiments were 2.05 g kg^?1 lotaustralin at the optimal values, i.e. temperature 65 °C, pressure 316 bar, 88% methanol modifier at a flow rate of 0.4 mL min^?1, and dynamic extraction time 90 min.     

Considerations of temperature in the context of the persistence classification in the EU

Simulation degradation studies for industrial chemicals, biocidal products and plant protection products are required in the EU to estimate half-lives in soil, water and sediment for the comparison to persistence criteria for hazard (P/vP) assessment, and for use in exposure assessments. There is a discrepancy between European regulatory approaches regarding the temperature at which degradation half-lives should be (1) measured in simulation degradation testing of environmental compartments, and (2) compared to the P/vP criteria. In this paper, an opinion is provided on the options for the experimental temperature and extrapolation to other conditions. A review of the historical development of persistence criteria did not give conclusive evidence of the temperature at which the half-lives that underpin the P-criteria were measured, but room temperature is likely. Half-lives measured at 20 °C are in line with the intentions of some international agreements, but in the EU there is a continued political debate regarding the relevant temperature for comparison with persistence criteria. Measuring degradation at 20 °C has the advantage that metabolites/transformation products can be identified with greater accuracy, and that kinetic fits to determine half-lives for parent compounds and metabolites carry less uncertainty. Extrapolation of half-lives to lower temperatures is possible for assessing environmental exposure, but the uncertainty of the persistence classification is smaller when measured half-lives are used for direct comparison with P/vP criteria, without extrapolation. Model simulations demonstrate the pattern of concentrations that can be expected for realistic worst case climate scenarios in the EU based on the half-life of 120 days in soil at 20 °C and of 40 days in water at 20 °C, and their temporal and spatial variability.