Alkylphenols (APs), alkylphenol ethoxylates (APEOs), ethoxycarboxylate metabolites (APECs) and bisphenol A were determined in surface water using solid-phase extraction (SPE) followed by triple-quadrupole LC-MS-MS. APs were separated by LC from APECs using an acetonitrile-water-gradient without the addition of any buffer. Nonylphenol ethoxycarboxylates (NPECs) interfere in the detection of nonylphenols (NPs) when using an acidic mobile phase, because they produce the same MS-MS fragment ions (219>133 and 147). 4n-NP shows the characteristic transition 219>106; it is well suited as internal standard. Nonylphenol ethoxylates NPE(n)Os (n=1-17) were analysed separately in a second run by positive ionization using an ammonium acetate mobile phase. Textile industry discharges, the corresponding wastewater treatment plant (WWTP) effluents and the receiving rivers in Belgium and Italy were analysed. Among the substances investigated, NPE1C and NPE2O exhibited the highest concentrations in the water samples, up to 4.5 microg l(-1) NPE1C in a WWTP effluent and 3.6 microg l(-1) NPE2O in a river. The highest NP levels were found in the receiving rivers (max. 2.5 microg l(-1)). The predicted no-effect concentration (PNEC) for NP of 0.33 microg l(-1) for water species was frequently exceeded in the surface waters investigated, suggesting potential adverse effects to the aquatic environment. 相似文献
Abstract: We reviewed the history and conservation of Sophora toromiro , a species that has been extinct in the wild since 1960 but has survived as scattered individuals in botanic gardens and private collections. The short-term conservation of S. toromiro is dependent on the management of surviving ex situ stocks. This is being achieved through international collaboration by a working group established to coordinate the conservation management of the species. Molecular evidence indicates that the species retains greater genetic variability than expected. The greatest amount of genetic variability was located in specimens outside botanic garden collections. No unmodified natural habitat survives on Rapa Nui ( Easter Island); so opportunities to establish a viable wild population are limited. Evidence from past reintroductions indicates that the best short-term opportunity for the species is through conventional horticultural management in botanic gardens and traditional farm plots on Rapa Nui. Some extinct-in-the-wild taxa (sensu World Conservation Union 1994), such as the Toromiro, retain genetic variability, and appropriate reintroduction sites exist. These taxa represent valid priorities for conservation management. 相似文献
The effectiveness of environmental protection measures is based on the early identification and diagnosis of anthropogenic pressures. Similarly, restoration actions require precise monitoring of changes in the ecological quality of ecosystems, in order to highlight their effectiveness. Monitoring the ecological quality relies on bioindicators, which are organisms revealing the pressures exerted on the environment through the composition of their communities. Their implementation, based on the morphological identification of species, is expensive because it requires time and experts in taxonomy. Recent genomic tools should provide access to reliable and high-throughput environmental monitoring by directly inferring the composition of bioindicators’ communities from their DNA (metabarcoding). The French-Swiss program SYNAQUA (INTERREG France-Switzerland 2017–2019) proposes to use and validate the tools of environmental genomic for biomonitoring and aims ultimately at their implementation in the regulatory bio-surveillance. SYNAQUA will test the metabarcoding approach focusing on two bioindicators, diatoms, and aquatic oligochaetes, which are used in freshwater biomonitoring in France and Switzerland. To go towards the renewal of current biomonitoring practices, SYNAQUA will (1) bring together different actors: scientists, environmental managers, consulting firms, and biotechnological companies, (2) apply this approach on a large scale to demonstrate its relevance, (3) propose robust and reliable tools, and (4) raise public awareness and train the various actors likely to use these new tools. Biomonitoring approaches based on such environmental genomic tools should address the European need for reliable, higher-throughput monitoring to improve the protection of aquatic environments under multiple pressures, guide their restoration, and follow their evolution. 相似文献
This study develops fine temporal (seasonal, day-of-week, diurnal) and vertical allocations of anthropogenic emissions for the TRACE-P inventory and evaluates their impacts on the East Asian air quality prediction using WRF-Chem simulations in July 2001 at 30-km grid spacing against available surface measurements from EANET and NEMCC. For NO2 and SO2, the diurnal and vertical redistributions of emissions play essential roles, while the day-of-week variation is less important. When all incorporated, WRF-Chem best simulates observations of surface NO2 and SO2 concentrations, while using the default emissions produces the worst result. The sensitivity is especially large over major cities and industrial areas, where surface NO2 and SO2 concentrations are reduced by respectively 3–7 and 6–12 ppbv when using the scaled emissions. The incorporation of all the three redistributions of emissions simulates surface O3 concentrations higher by 4–8 ppbv at night and 2–4 ppbv in daytime over broad areas of northern, eastern and central China. To this sensitivity, the diurnal redistribution contributes more than the other two. 相似文献
Using proton transfer reaction mass spectrometry equipped with a quadrupol mass analyser to quantify the biosphere-atmosphere exchange of volatile organic compounds (VOC), concentrations of different VOC are measured sequentially. Depending on how many VOC species are targeted and their respective integration times, each VOC is measured at repeat rates on the order of a few seconds. This represents an order of magnitude longer sample interval compared to the standard eddy covariance (EC) method (5–20 Hz sampling rates). Here we simulate the effect of disjunct sampling on EC flux estimates by decreasing the time resolution of CO2 and H2O concentrations measured at 20 Hz above a temperate mountain grassland in the Austrian Alps. Fluxes for one month are calculated with the standard EC method and compared to fluxes calculated based on the disjunct data (1, 3 and 5 s sampling rates) using the following approaches: i) imputation of missing concentrations based on the nearest neighbouring samples (iDECnn), ii) imputation by linear interpolation (iDECli), and iii) virtual disjunct EC (vDEC), i.e. flux calculation based solely on the disjunct concentrations. It is shown that the two imputation methods result in additional low-pass filtering, longer lag times (as determined with the maximum cross-correlation method) and a flux loss of 3–30% as compared to the standard EC method. A novel procedure, based on a transfer function approach, which specifically corrects for the effect of data treatment, was developed, resulting in improved correspondence (to within 2%). The vDEC method yields fluxes which approximate the true (20 Hz) fluxes to within 3–7% and it is this approach we recommend because it involves no additional empirical corrections. The only drawback of the vDEC method is the noisy nature of the cross-correlations, which poses problems with lag determination – practical approaches to overcome this limitation are discussed. 相似文献
Irrigated agriculture is a main user of groundwater. Achieving a sustainable use of groundwater will often require agricultural
land-use changes such as shifting to entirely different kinds of crops and/or technologies. Enhanced understanding of land-use
change is hence required for developing policies for a sustainable water future. We use an agent-based model to investigate
the history of irrigated agriculture in the Upper Guadiana Basin, Spain, in order to learn about the influence of farmers’
characteristics on land-use change and associated groundwater over-use. A shift from vineyards and cereals to horticultural
crops would provide a possibility for higher income with less water use. Such a shift cannot be observed historically. The
model results suggest that risk aversion and path dependency are insufficient to explain this observation, and the organisational
set-up of farms limiting the maximum labour force needs to be considered as additional explanatory factor. Furthermore, it
is shown that different types of farms existing in the UGB can be expected to exhibit distinct responses to drivers of land-use
change such as agricultural policies. It is concluded that a sound understanding of the social system making use of a resource
is required to solve problems of resource over-use. This article demonstrates that agent-based models can be useful tools
to enhance such an understanding even in situations of scarce and uncertain data that are often encountered when dealing with
resource-use problems. 相似文献
A cyclone with a 47 mm after-filter has been developed for ambient air size-selective monitoring. It has been extensively evaluated with laboratory-generated aerosol. Variation of the pressure drop and 50% cut point with flow rate show that the cyclone operates in a single flow regime with a vortex in the outlet flow. The particle size cutoff curve is comparable in sharpness to a cascade impactor and is the same for solid or liquid particles. At 21.7 L/min, D50 is 2.5μm and at 15.4 L/min, D50 is 3.5 μm. Collection efficiency data for flow rates from 8 to 27 L/min fit a universal curve when plotted vs. the normalized particle diameter, (D-D50)/D50 Reentrainment of previously deposited particles is less than 1 % of the loading per day. In field tests the cyclone has proved to be a very satisfactory size-selective sampler. 相似文献
Based on multi-year measurements of CH4 exchange in sub-daily resolution we show that clear-cutting of a forest in Southern Germany increased soil temperature and moisture and decreased CH4 uptake. CH4 uptake in the first year after clear-cutting (−4.5 ± 0.2 μg C m−2 h−1) was three times lower than during the pre-harvest period (−14.2 ± 1.3 μg C m−2 h−1). In contrast, selective cutting did not significantly reduce CH4 uptake. Annual mean uptake rates were −1.18 kg C ha−1 yr−1 (spruce control), −1.16 kg C ha−1 yr−1 (selective cut site) and −0.44 kg C ha−1 yr−1 (clear-cut site), respectively. Substantial seasonal and inter-annual variations in CH4 fluxes were observed as a result of significant variability of weather conditions, demonstrating the need for long-term measurements. Our findings imply that a stepwise selective cutting instead of clear-cutting may contribute to mitigating global warming by maintaining a high CH4 uptake capacity of the soil. 相似文献
Background, aim, and scope The enzyme-linked receptor assay (ELRA) detects estrogenic and anti-estrogenic effects at the molecular level of receptor
binding and is a useful tool for the integrative assessment of ecotoxicological potentials caused by hormonally active agents
(HAA) and endocrine disrupting compounds (EDC). The main advantage of the ELRA is its high sample throughput and its robustness
against cytotoxicity and microbial contamination. After a methodological adaptation to salinity of the ELRA, according to
the first part of this study, which increased its salinity tolerance and sensitivity for 17-β-estradiol, the optimised ELRA
was used to investigate 13 native sediments characterised by different levels of salinity and chemical contamination. The
applicability of the ELRA for routine analysis in environmental assessment was evaluated. Salinity is often a critical factor
for bioassays in ecotoxicological sediment assessment. Therefore, salinity of the samples was additionally adjusted to different
levels to characterise its influence on elution and binding processes of receptor-binding substances.
Materials and methods The ELRA was carried out with the human estrogen receptor α (ER) in a 96-well microplate format using the experimental setup
known from the competitive immunoassay based on ligand–protein interaction. It is an important improvement that a physiologically
relevant receptor was used as a linking protein instead of an antibody. The microplates were coated with a 17-β-estradiol-BSA
conjugate, and dilution series of estradiol and of native sediment samples were added and incubated with the ER. After a washing
step, a biotinylated mouse anti-ER antibody was added to each well. Receptor binding to estradiol, agonistic and antagonistic
receptor binding, were determined by a streptavidin-POD-biotin complex with subsequent measurement of the peroxidase activity
at the wavelength of 450 nm using a commercial ELISA multiplate reader. The sediment elutriates and pore water samples of
sediments were tested in a dilution series to evaluate at which dilution step the receptor-binding potential ends. In the
elution process (see Section 2.1 to 2.2), a method was developed to adjust the salinity to the levels of the reference testings, which offers an appropriate option
to adjust the salinity in both directions. Statistical evaluation was made with a combination of the Mann–Whitney U test and the pT-method.
Results This part of the study characterised the environmental factor ‘salinity’ for prospective applications of the ELRA. Using reference
substances such as 17-β-estradiol, the ELRA showed sigmoid concentration-effect relations over a broad range from 0.05 μg/l
to 100 μg/l under physiological conditions. After methodological optimisation, both sensitivity and tolerance of the assay
against salinity could be significantly raised, and the ELRA became applicable under salinity conditions up to concentrations
of 20.5‰. The mean relative inter-test error (n = 3) was around 11% with reference substances and below 5% for single sediments elutriates in three replicates each. For
sediment testings, the pore water and different salinity-adjusted elutriates of 13 sediments were used. A clear differentiation
of the receptor-binding potential could be reached by application of the pT-method. Thereby, pT-values from one to six could
be assigned to the sediments, and the deviation caused by the different salinity conditions was one pT-value. The mean standard
deviation in the salinity adaptation procedure of the elutriates was below 5%.
Discussion Although the ELRA has already been used for assessments of wastewater, sludge and soil, its applicability for samples to different
salinity levels has not been investigated so far. Even if the ELRA is not as sensitive as the E-screen or the YES-assay, with
regard to reference substances like 17-β-estradiol, it is a very useful tool for pre-screening, because it is able to integrate
both estrogenic as well as anti-estrogenic receptor-binding effects. According to the results of sediment testing, and given
the integrative power to detect different directions of effects, the ELRA shows sufficient sensitivity and salinity tolerance
to discriminate receptor-binding potentials in environmental samples.
Conclusions The optimised ELRA assay is a fast, cost-effective, reliable and highly reproducible tool that can be used for high-throughput
screening in a microplate format in detecting both estrogenic and anti-estrogenic effects. Additionally, the ELRA is robust
against microbial contaminations, and is not susceptible towards cytotoxic interferences like the common cell-culture methods.
The general applicability and sufficient sensitivity of the ELRA was shown in freshwater environments. Marine and brackish
samples can be measured up to salinity levels of 20.5‰.
Recommendations and perspectives In view of the proven sensitivity, functionality and the fastness of the ELRA, it is recommendable to standardise the test
method. At the moment, no adequate in vitro test procedure exists which is standardised to DIN or ISO levels. The E-screen
and the yeast estrogen/androgen screens (YES/YAS) sometimes underlie strong cytotoxic effects, as reported in the first part
of this study. Further development of an ELRA assay using human androgen receptors appears to be very promising to gain information
about androgenic and anti-androgenic effects, too. This would offer a possibility to use the ELRA as a fast and reliable pre-screening
tool for the detection of endocrine potentials, thus minimising time and cost-expensive animal experiments. 相似文献
A new analytical method using accelerated solvent extraction was developed for the determination of 10 particle-associated polar and semipolar pesticides. In addition, six deuterated analogues of the target compounds were evaluated as internal standards. The method yielded acceptable accuracy (73–103% recovery) and precision (<25% relative standard deviation) for eight compounds. Using size exclusion chromatography (SEC) as cleanup step resulted in higher recoveries compared to solid phase extraction (SPE) cleanup.
Deuterated standards with 10 or more deuterium atoms performed well as internal standards concerning similar recovery and correlation with the target analytes.
The method was employed to extract particle-associated pesticides from 16 streams located in an area with intense agriculture in France. Acetochlor, pirimicarb, tebuconazole, fenpropidin, -endosulfan and chlorfenvinphos were detected at concentrations up to 1 mg kg−1 dry weight. A comparison with aquatic toxicity data indicated potential risk to the benthic fauna exposed to these concentrations of pirimicarb, -endosulfan and chlorfenvinphos.
We suggest that the method presented here be used for the extraction and quantitation of particle-associated polar pesticides. 相似文献