Monoterpene emissions and carbonyl compound air concentrations during the blooming period of rape (Brassica napus)

An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h⁻¹ m⁻² (30–60 ng h⁻¹ per g dry plant––540–1080 ng h⁻¹ per plant), in total. Limonene, -thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (M_S) and temperature coefficients were determined: β_limonene=0.108 K⁻¹ and M_S=14.57 μg h⁻¹ m⁻²; β_sabinene=0.095 K⁻¹ and M_S=5.39 μg h⁻¹ m⁻².

The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.     

Climate simulations using the GCRC 2-D zonally averaged statistical dynamical climate model

The two-dimensional statistical dynamical climate model, recently developed at the Global Change Research Center (GCRC 2D climate model) is presented and discussed. The model solves the 2-D primitive equations in finite difference form (mass continuity, Newton's second law, and the first law of thermodynamics) for the prognostic variables zonal mean density, zonal mean zonal velocity, zonal mean meridional velocity, and zonal mean temperature on a grid that has 18 nodes in latitude and 9 vertical nodes (plus the surface). The equation of state, p = ρRT and an assumed hydrostatic atmosphere, δp = −ρgδz, are used to diagnostically calculate the zonal mean pressure and vertical velocity for each grid node, and the moisture balance equation is used to estimate the precipitation rate.

The performance of the model at simulating the two-dimensional temperature, zonal winds, and mass stream function is discussed here. The strengths and weaknesses of the model are highlighted and plans for future model experiments and improvements are given. The parameterization of the transient eddy fluxes of heat and momentum developed by Stone and Yao (1987 and 1990) are used with small modifications. These modifications are shown to improve the performance of the model at simulating the observed climate system as well as increase the model's computational stability.     

Socio-economic vulnerability to climate change in the central mountainous region of eastern Mexico

Climate change effects are expected to be more severe for some segments of society than others. In Mexico, climate variability associated with climate change has important socio-economic and environmental impacts. From the central mountainous region of eastern Veracruz, Mexico, we analyzed data of total annual precipitation and mean annual temperature from 26 meteorological stations (1922–2008) and from General Circulation Models. We developed climate change scenarios based on the observed trends with projections to 2025, 2050, 2075, and 2100, finding considerable local climate changes with reductions in precipitation of over 700 mm and increases in temperature of ~9°C for the year 2100. Deforested areas located at windward were considered more vulnerable, representing potential risk for natural environments, local communities, and the main crops cultivated (sugarcane, coffee, and corn). Socio-economic vulnerability is exacerbated in areas where temperature increases and precipitation decreases.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0690-4) contains supplementary material, which is available to authorized users.     

Guest dechlorination and covalent capture following photoexcitation of inclusion complexes in water

Photoexcitation of complexes between cyclophane 1 and 1- or 2-chloronaphthalene in aqueous solution leads to rapid dechlorination of the guest, a reaction driven by electron transfer from host to excited guest. The main photoproducts contain a naphthyl group covalently attached to the host framework. The results may lead to new approaches for remediating water contaminated with chlorinated aromatic compounds.     

Methane fluxes from tundra soils and snowpack in the maritime Antarctic

Methane fluxes were measured from three exposed tundra sites and four snowpack sites on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were −15.3 μg m⁻² h⁻¹ and −14.3 μg m⁻² h⁻¹, respectively. The fluxes from tundra site with fresh penguin dropping addition showed positive values with the average of 36.1 μg m⁻² h⁻¹, suggesting that the deposition of fresh droppings greatly enhanced CH₄ emissions from the poor Antarctic tundra during penguin breeding periods. The summertime variation in CH₄ flux was correlated with surface ground temperature and the precipitation. The correlation between the flux and PT₀, which is the product of the precipitation and surface ground temperature, was quite strong. The diurnal cycle of CH₄ flux from the tundra soils was not obtained due to local fluky weather conditions. The fluxes through four snowpack sites were also obtained by the vertical CH₄ concentration gradient and their average fluxes were −46.5 μg m⁻² h⁻¹, −28.2 μg m⁻² h⁻¹, −46.4 μg m⁻² h⁻¹ and −17.9 μg m⁻² h⁻¹, respectively, indicating that tundra soils under snowpack also consume atmospheric CH₄ in the maritime Antarctic; therefore these fluxes could constitute an important part of the annual CH₄ budget for Antarctic tundra ecosystem.     

Study on the fluorescence characteristics of bromadiolone in aqueous and organized media and application in analysis

The fluorescence spectroscopic behavior of bromadiolone (anticoagulant rodenticide), a substituted 4-hydroxycoumarin derivative, was investigated in water and in organized media like micelles and cyclodextrins. A detailed study on various photophysical parameters like fluorescence intensity (I_F), quantum yield (), lifetime (τ) and steady state fluorescence anisotropy (r) of bromadiolone in aqueous and in organized media was carried out. Bromadiolone in aqueous solution was observed to be in an aggregated state, thereby showing weak emission due to self-quenching. Marked enhancement of fluorescence intensity was observed in organized media like micelles and β-cyclodextrin. A preliminary investigation has been done to find out whether this enhancement of fluorescence can be used to develop a sensitive analytical method for determination of bromadialone in aqueous media. A linear relationship between the fluorescence intensity and concentration of bromadiolone was observed in the range of 0.15–7.9 μg ml⁻¹ in cetyltrimethylammonium bromide (CTAB) and 0.5–26.4 μg ml⁻¹ in β-cyclodextrin medium. The lower detection limit was found to be 37 ng ml⁻¹ in presence of CTAB and 23 ng ml⁻¹ in β-cyclodextrin. Comparison with 4-hydroxycoumarin, an unsubstituted analogue, was made.     

Removal of a cationic dye from aqueous solutions by adsorption onto bentonite clay

The ability of bentonite to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Maximum adsorption of the dye, i.e. >90% has been achieved in aqueous solutions using 0.05 g of bentonite at a pH of 9. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated from the slope and intercept of the linear plots of ln K_D against 1/T. Analysis of adsorption results obtained at 298, 308, 318 and 328 K showed that the adsorption pattern on bentonite seems to follow the Langmuir, Freundlih and D–R isotherms. The temperature increase reduces adsorption capacity by bentonite, due to the enhancement of the desorption step in the mechanism. The numerical values of sorption free energy (E_a) of 1.00–1.12 kJ mol⁻¹ indicated physical adsorption. The kinetic data indicated an intraparticle diffusion process with sorption being first order. The rate constant k was 0.526 min⁻¹. The concentration of malachite green oxalate was measured before and after adsorption by using UV–Vis spectrophotometer.     

Effects of solution conditions on the precipitation of phosphate for recovery. A thermodynamic evaluation

To understand the effects of solution conditions on the precipitation of calcium phosphates from wastewater for recovery, a computer programme PHREEQC was employed to calculate the speciation and saturation-index (SI) with respect to hydroxyapatite of a chemically defined precipitation system, which contains phosphate of 1–200 mg P/l, with Ca/P molar ratios of one to 10 times of the stoichiometric calcium to phosphorus molar ratio of hydroxyapatite, at a pH range of 7.0–11.0. The results show that the SI is respectively the logarithmic function of the phosphate concentration and the calcium concentration, increasing with the increase of either of them; the SI is a polynomial function of the solution pH value and increases with its increase, and the effect of solution pH value is due to its influence on base uptake of the precipitation reaction and the speciation of phosphate and calcium ions; the SI is also a logarithmic function of the solution ionic strength but decreases with its increase; at the temperature range of 5–30 °C the SI increases linearly with solution temperature and the effect of temperature is also due to its influence on the speciation of phosphate and calcium ions.     

A simple effective procedure for the determination of adenosine triphosphate in soils

A simple method for the extraction and determination of adenosine 5′-triphosphate (ATP) in soil is described. ATP was extracted by stirring with dimethyl sulphoxide (DMSO), followed by adding 0.01 M trisodium phosphate (Na₃PO₄) buffer solution for a further dispersion. The ATP content was quantitatively measured by luciferin-luciferase system employing a standard addition technique. The method was most efficient in comparison with 7 other extraction procedures. The recoveries of ATP in spiked soil were found to be approximately 100 %. ATP contents in 16 selected soils were in ranges of 0.76±0.05 – 7.79±0.83 μg/g (dry weight). A significant correlation between ATP amounts and biomasses in these soils was also observed.     

Climate Change and Population Growth in Timor Leste: Implications for Food Security

The climate in Timor Leste (East Timor) is predicted to become about 1.5 °C warmer and about 10 % wetter on average by 2050. By the same year, the population is expected to triple from 1 to 2.5–3 million. This article maps the predicted changes in temperature and rainfall and reviews the implications of climate change and population growth on agricultural systems. Improved cultivars of maize, rice, cassava, sweet potato and peanuts with high yield performance have been introduced, but these will need to be augmented in the future with better adapted cultivars and new crops, such as food and fodder legumes and new management practices. The requirements for fertilizers to boost yields and terracing and/or contour hedgerows to prevent soil erosion of steeply sloping terrain are discussed. Contour hedges can also be used for fodder for improved animal production to provide protein to reduce malnutrition.     

Distribution of pesticides and heavy metals in trophic chain

Determination of triazines herbicides (atrazine and simazine) by high performance liquid chromatography (HPLC) in samples of trophic chain were worked out. Determination limits of 0.5 μg g⁻¹ for atrazine, 0.8 μg g⁻¹ for simazine with pesticides recovery of 70–77% in trophic chain samples were obtained. The content of simazine in soils was in range 1.72–57.89 μg g⁻¹, in grass 5–88 μg g⁻¹, in milk 2.32–15.29 μg g⁻¹, in cereals 10.98–387 μg g⁻¹, in eggs 30.14–59.48 μg g⁻¹, for fruits: 2.45–6.19 μg g⁻¹. The content of atrazine in soils was in range 0.69–19.59 μg g⁻¹, in grass 7.85–23.85 μg g⁻¹, in cereals 1.88–43.08 μg g⁻¹. Cadmium, lead and zinc were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) in the same samples as atrazine and simazine. Determination limits for cadmium 5 × 10⁻³ μg g⁻¹, for lead 1 × 10⁻² μg g⁻¹, and for zinc 0.2 × 10⁻³ μg g⁻¹, were obtained. The content of cadmium in soil was in range 0.13–5.89 μg g⁻¹, in grass 114–627.72 × 10⁻³ μg g⁻¹, in milk 8.88–61.88 × 10⁻³ μg g⁻¹, in cereals 0.20–0.31 μg g⁻¹, in eggs 0.11–0.15 μg g⁻¹, in fruits 0.23–0.59 μg g⁻¹. The content of lead in soils was in range 0.57–151.50 μg g⁻¹, in grass 0.16–136.57 μg g⁻¹, in milk 1.16–3.74 μg g⁻¹, in cereals 1.05–5.47 μg g⁻¹, in eggs 5.79–55.87 μg g⁻¹, in fruits 21.00–87.36 μg g⁻¹. Zinc content in soil was in range 9.15–424.5 μg g⁻¹, in grass 35.20–55.87 μg g⁻¹, in milk 20.00–34.38 μg g⁻¹, in cereals 14.94–28.78 μg g⁻¹, in eggs 15.67–32.01 μg g⁻¹, in fruits 14.94–18.88 μg g⁻¹.

Described below extraction and mineralization methods for particular trophic chains allowed to determine of atrazine, simazine, cadmium, lead and zinc with good repeatability and precision. Emphasis was focused on liquid–liquid extraction and solid-phase extraction of atrazine and simazine from analysed materials, as well as, on monitoring the content of herbicides and metals in soil and along trophic chain. Higher concentration of pesticides in samples from west region of Poland in comparison to that of east region is likely related to common applying them in Western Europe in relation to East Europe. The content of metals strongly depends on samples origin (industry area, vicinity of motorways).     

Pesticides in rain

40 rainwater samples were collected in Hannover and near Peine (Lower Saxony, Germany) in 1992 using a wet-only collector. The samples were extracted by solid phase extraction and analyzed by GC/MS for 59 pesticides. 11 pesticides were found in more than 10 samples. The highest concentrations were observed for terbuthylazine (0.003 – 0.52 μg/L ), metolachlor (0.003 – 0.51 pg/L, mean: 0.10 μg/L), metalaxyl (0.006 – 0.48 μg/L, mean: 0.10 pg/L) and chlorothalonil (0.003 – 1.1 μg/L, mean: 0.16 μg/L). The concentrations show a seasonal dependence reflecting the application periods.     

Use of oyster, Crassostrea gigas, and ambient water to assess metal pollution status of the charting coastal area, Taiwan, after the 1986 green oyster incident

Most of the oyster mariculture beds in Taiwan are in areas located along the west of the island. One of these areas is the Charting coast, where green oysters were found in 1986. During this incident, which became internationally notorious, mass mortality occurred in the Charting oyster beds. After this discovery, measures were taken by the authorities to counter pollution which lead to the problem. The effectiveness of these pollution control actions was evaluated in this study. Two water column indicators, particulate and sediment, and oysters were sampled and analyzed for metals (Cu, Zn, Pb, Ni) in Charting and its neighboring areas, Kuen-Shen Lake and Shin-Da Harbor, and the control area/station, Dah-Pen Wan. The current study shows that copper and zinc concentrations in both oysters and particulates significantly decreased in the Charting area, compared with concentrations found during the period of the green oyster incident. Six years after the incident, the copper concentration in oysters had fallen from a high of 4400 μg/g dry weight to an average of 300±69 μg/g dry weight, figures similar to the copper concentration in 1982. The pollution control actions taken after the incident are believed to be the cause of this recovery of the coastal environment. Nevertheless, Charting still produced oysters with the highest copper and zinc concentrations among the areas investigated. Further measures currently being taken by the government, including removing the sediment of some portions of Erhjin Chi, should be able to bring the oyster copper concentrations down to the levels similar to those observed in the neighboring area, (average concentration below 200 μg/g dry weight or all time maximum concentration below 500 μg/g dry weight).     

Utilization and degradation of imazaquin by a naturally occurring isolate of Arthrobacter crystallopoietes

A species of bacteria that is capable of utilizing imazaquin as the sole carbon source was isolated from soil with repeated imazaquin applications, and was identified as Arthrobacter crystallopoietes (designated as strain “WWX-1”). This isolate degrades imazaquin as high as 200 μg ml⁻¹, and the estimated dissipation half-lives increased from 1.51 d for the treatment at 50 μg ml⁻¹ to 4.75 d for 200 μg ml⁻¹. Optimal growth of WWX-1 in mineral salt medium with 50 μg ml⁻¹ imazaquin was obtained at 35 °C and a pH of 5.0. Growth of WWX-1 was also observed in mineral salt medium with the addition of other imidazolinone herbicides such as imazethapyr and imazapyr, but not with different classes of herbicides such as metsulfuron-methyl. Two imazaquin metabolites were detected, and spectral analysis with HPLC–MS, ¹H NMR, and IR revealed one metabolite with a molecular weight (MW) of 199 as quinoline-2,3-dicarboxylic anhydride. We propose that A. crystallopoietes (WWX-1) could serve as an efficient biodegradation system for remediation of water and soils that are heavily contaminated with imazaquin or other structurally similar chemicals.     

The effects of particle size, organic matter content, crop residues and dissolved organic matter on the sorption kinetics of atrazine and isoproturon by clay soil

Reliable predictions of the fate and behaviour of pesticides in soils is dependent on the use of accurate ‘equilibrium’ sorption constants and/or rate coefficients. However, the sensitivity of these parameters to changes in the physicochemical characteristics of soil solids and interstitial solutions remains poorly understood. Here, we investigate the effects of soil organic matter content, particle size distribution, dissolved organic matter and the presence of crop residues (wheat straw and ash) on the sorption of the herbicides atrazine and isoproturon by a clay soil. Sorption K_d's derived from batch ‘equilibrium’ studies for both atrazine and isoproturon by <2 mm clay soil were approximately 3.5 L/kg. The similarity of K_oc's for isoproturon sorption by the <2 mm clay soil and <2 mm clay soil oxidised with hydrogen peroxide suggested that the sorption of this herbicide was strongly influenced by soil organic matter. By contrast, K_oc's for atrazine sorption by oxidised soil were three times greater than those for <2 mm soil, indicating that the soil mineral components might have affected sorption of this herbicide. No significant differences between the sorption of either herbicide by <2 mm clay soil and (i) <250 μm clay soil, (ii) clay soil mixed with wheat straw or ash at ratios similar to those observed under field conditions, (iii) <2 mm clay soil in the presence of dissolved organic matter as opposed to organic free water, were observed.     

Short-term toxicity of pyraclofos used as a blackfly larvicide on non-target aquatic fauna in a tropical environment

Among the many larvicides tested for the control of s.l. larvae, the vector of human onchocerciasis in West Africa, pyraclofos proved to be 100% effective at 100 μg × L⁻¹ for 10 min in river, with a carry of 20 km at 100 m³ × sec⁻¹. Tests were then performed both in laboratory and field conditions to evaluate its toxicity on the non-target aquatic fauna. In experimental short-term gutter tests, the detachment of the total benthic insects was 35% at 100 μg × L⁻¹ for 10 min against 17% for temephos at the same dose and 59% for chlorphoxim at 50μg × L⁻¹ for 10 min. , and were the most affected organisms. The treatment of a river resulted in a considerable detachment of the same taxonomic groups, plus Orthocladiinae. On the other hand, investigations conducted in tanks showed that the 24-hr LC₅₀ for is 150 μg × L⁻¹ and that for 170 μg × L⁻¹, values which are not very different from the operational dose of the larvicide (100 μg × L⁻¹ for 10 min.). Nevertheless, in a river, no fish mortality was recorded. Based on fish LC₅₀ and drift of benthic insects, pyraclofos at 100 μg × L⁻¹ was judged to be less toxic to aquatic fauna in the short term than permethrin and carbosulfan.     

Release flux of mercury from different environmental surfaces in Chongqing, China

An investigation was conducted to estimate mercury emission to the atmosphere from different environmental surfaces and to assess its contribution to the local mercury budget in Chongqing, China. Mercury flux was measured using dynamic flux chamber (DFC) at six soil sites of three different areas (mercury polluted area, farmland and woodland) and four water surfaces from August 2003 to April 2004. The mercury emission fluxes were 3.5 ± 1.2–8.4 ± 2.5 ng m⁻² h⁻¹ for three shaded forest sites, 85.8 ± 32.4 ng m⁻² h⁻¹ for farming field, 12.3 ± 9.8–733.8 ± 255 ng m⁻² h⁻¹ for grassland sites, and 5.9 ± 12.6–618.6 ± 339 ng m⁻² h⁻¹ for water surfaces. Mercury exchange fluxes were generally higher from air/water surfaces than from air/soil surfaces. The mercury negative fluxes were found in tow soil sites at overcast days (mean = −6.4 ± 1.5 ng m⁻² h⁻¹). The diurnal and seasonal variations of mercury flux were observed in all sites. The mercury emission responded positively to the solar radiation, but negatively to the relative humidity. The mercury flux from air/soil surfaces was significantly correlated with soil temperature, which was well described by an Arrhenius-type expression with activation energy of 31.1 kcal mol⁻¹. The annual mercury emission to the atmosphere from land surface is about 1.787 t of mercury in Chongqing.     

The enhancement of photodegradation efficiency using Pt-TiO2 catalyst

The residues from the extraction of lead/zinc (Pb/Zn) ores of most Pb/Zn mines are permanently stored in tailings ponds, which require revegetation to reduce their environmental impact. This can only be done if the main constraints on plant establishment are evaluated. This can readily be done by field and greenhouse studies.

To test this, the properties of different tailings from Lechang Pb/Zn mine located at the north of Guangdong Province in southern China have been studied. Physical and chemical properties including concentrations of metals (Pb, Zn, Cd and Cu) in the tailings and soils collected from different sites have been measured. The results showed that tailings contain low nitrogen (0.016–0.075%), low-organic matter (0.58–1.78%), high salt (3.55–13.85 dS/m), and high total and diethylene–tetramine–pentaacetic acid (DTPA)-extractable metal concentrations (total: 1019–1642 μg g⁻¹ Pb, 3078–6773 μg g⁻¹ Zn, 8–23 μg g⁻¹ Cd, and 85–192 μg g⁻¹ Cu; DTPA-extractable: 59–178 μg g⁻¹ Pb, 21–200 μg g⁻¹ Zn, 0.30–1.5 μg g⁻¹ Cd, and 4.3–12 μg g⁻¹ Cu). Aqueous extracts of tailings/soils (10%, 20% and 30%, w/v) from different sites were prepared for testing their effects on seed germination and root elongation of a vegetable crop Brassica chinensis and a grass species Cynodon dactylon. It was found that root elongation provided a better evaluation of toxicity than seed germination. The ranking of toxicity using root elongation was: high-sulfur tailings>tailingdam>sparsely vegetated tailings>densely vegetated tailings>mountain soil for both plants. This order was consistent with DTPA-extractable Pb contents in the tailings and soils. B. chinensis seedlings were then grown in the mixtures of different proportions of tailings and farm soil for 4 weeks, and the results (dry weights of seedlings) were in line with the root elongation test. All these demonstrated that heavy metal toxicity, especially available Pb, low content of nutrient, and poor physical structure were major constraints on plant establishment and colonization on the Pb/Zn mine tailings.     

On the performance of Fe and Fe,F doped Ti-Pt/PbO2 electrodes in the electrooxidation of the Blue Reactive 19 dye in simulated textile wastewater

The electrochemical performance of pure Ti–Pt/β-PbO₂ electrodes, or doped with Fe and F (together or separately), in the oxidation of simulated wastewaters containing the Blue Reactive 19 dye (BR-19), using a filter-press reactor, was investigated and then compared with that of a boron-doped diamond electrode supported on a niobium substrate (Nb/BDD). The electrooxidation of the dye simulated wastewater (volume of 0.1 l, with a BR-19 initial concentration of 25 mg l⁻¹) was carried out under the following conditions: current density of 50 mA cm⁻², volume flow rate of 2.4 l h⁻¹, temperature of 25 °C and electrode area of 5 cm². The performances of the electrodes in the dye decolorization were quite similar, achieving 100% decolorization, and in some cases 90% decolorization was achieved by applying only ca. 0.3 A h l⁻¹ (8 min of electrolysis). The reduction of the simulated wastewater organic load, monitored by its total organic carbon content (TOC), was greater for the Ti–Pt/β-PbO₂–Fe,F electrode obtained from an electrodeposition bath containing 1 mM Fe³⁺ and 30 mM F⁻. In this case, after 2 h of electrolysis the obtained TOC reduction was 95%, while for the pure β-PbO₂ and the Nb/BDD electrodes the reductions were 84% and 82%, respectively.     

Solubilization of substituted indole compounds by beta-cyclodextrin in water

The solubilization of four pairs of substituted indole compounds (SICs) by β-cyclodextrin (β-CD) in water was investigated. The results show that 1,2,3,4-tetrahydrocarbazole and N-methyl-1,2,3,4-tetrahydrocarbazole form 1:1 inclusion complexes with β-CD, while the other six SICs form 1:2 inclusion complexes, respectively. To each pair of SICs with similar structures, the differences between their solubilization in β-CD/water solutions has been explained by the difference of their contact area within the β-CD cavity, the difference of their molecule polarity, or the presence of hydrogen bond between SIC molecule and β-CD molecule.