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Amino acids are an important and highly dynamic fraction of organic N in soils and their determination in soil without derivatization is challenging due to the difficulties in separation and detection of trace amounts of these polar analytes. In the present work, we developed an analytical method to quantify 20 free amino acids in aqueous soil extracts without derivatization. The method employed hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC–MS/MS) technique combined with a cation exchange solid phase extraction (SPE). Four stable isotope labelled amino acids were used as internal standards to improve the method performance. Good separation of 20 underivatized amino acids was achieved within 12 min. The limit of detection (LODs) and limit of quantification (LOQs) were in the range of 13–384 ng g−1 and 43–1267 ng g−1 (dry soil basis), respectively. The results showed that overall recoveries with high precision were obtained for the extracted free amino acids from ten different soils. The overall recoveries of 18 amino acids were similar for the ten soils used, which differed substantially in organic C content and in other properties as soil texture and pH. For most of the amino acids, the average recoveries from soil extracts were between 74% and 117%, with the exception of Met (31%), Pro (52%) and Arg (68%). Variability was within acceptable limits (relative standard deviations were between 4% and 13%), with the exception of Met (relative standard deviation = 90%) and Arg (relative standard deviation = 53%). Thus the proposed method with high throughout and high analyte specificity shows great promise for consistent analysis of free amino acids extracted from soils and offers new horizons for the analysis of amino acids in terrestrial and aquatic ecosystem.

Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation. Ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-QqQ-MS/MS) has become the most promising platform, already applied successfully for analysis of selected PFRs in some environmental matrices like water and wastewater. However, the presence of some interferences from the dissolvent, the equipment and the used materials should be taken into account. The procedure involves: The first determination of PFRs by UHPLC-QqQ-MS/MS using a trap column to distinguish the interferences coming from the instrument and mobile phases.The optimization of the LC separation to distinguish all target compounds and their interferences.This method coupled to a solid-phase extraction (SPE) improve the detection and quantification of PFRs., This work has been supported by the Spanish Ministry of Economy and Competitiveness through the projects GCL2011-29703-C02-02 (http://mefturia.es) and GCL2015-64454-C2-1-R (ECO2risk-dds) and the University of Valencia through the project (UV-INV-AE15-348995). María Lorenzo also acknowledges to the Foundation “Tatiana Pérez de Guzmán el Bueno” for the grant to get the PhD.

Evidence is presented that the oxygen demand associated with photochemical processes in the surface layer of oceans and seas worldwide is of the same order of magnitude as the amount of oxygen released by photosynthesis of the world's marine phytoplankton. Both estimates are of necessity quite rough and therefore the agreement between oxygen loss and production, earlier found only locally in the Atlantic Ocean and the North Sea, came as a surprise. The heavy photochemical oxygen demand of the world's oceans must be explored further in oxygen budget studies by biogeochemical modelling in which special attention is paid to regional and temporal-differences in the vertical stratification regime at the surface. Indeed, stratification is the candid() sine qua non for photochemical processes that are driven by ultraviolet radiation. Oxygen cannot be expected to be released from the sea to the atmosphere in the permanently stratified open ocean when year-round the oxygen loss associated with photochemistry is so high. In the upper layer of sea and ocean regions of the temperate zone vertical stratification is only pronounced during spring, summer and early autumn, so photochemical oxygen demand there is restricted to those months. We argue that the constancy of the oxygen concentration observed at the surface of the oceans in the tropics and subtropics (80% of Earth's marine regions) is the consequence of the balance between three processes that influence oxygen dissolved in seawater: loss due to photochemical processes and to the activity of microheterotrophs on the one hand, photosynthetic oxygen production by phytoplankton on the other. (C) 2015 Elsevier B.V. All rights reserved

Nadal-Romero...[et.al.], Precipitation has been recognized as one of the main factors driving soil erosion and sediment yield (SY), and its spatial and temporal variability is recognized as one of the main reasons for spatial and temporal analyses of soil erosion variability. The weather types (WTs) approach classifies the continuum of atmospheric circulation into a small number of categories or types and has been proven a good indicator of the spatial and temporal variability of precipitation. Thus, the main objective of this study is to analyze the relationship between WTs, runoff, soil erosion (measured in plots), and sediment yield (measured in catchments) in different areas of the Iberian Peninsula (IP) with the aim of detecting spatial variations in these relationships. To this end, hydrological and sediment information covering the IP from several Spanish research teams has been combined, and related with daily WTs estimated by using the NMC/NCAR 40-Year Reanalysis Project. The results show that, in general, a few WTs (particularly westerly, southwesterly and cyclonic) provide the largest amounts of precipitation; and southwesterly, northwesterly and westerly WTs play an important role in runoff generation, erosion and sediment yield as they coincide with the wettest WTs. However, this study highlights the spatial variability of erosion and sediment yield in the IP according to WT, differentiating (1) areas under the influence of north and/or north-westerly flows (the north coast of Cantabria and inland central areas), (2) areas under the influence of westerly, southwesterly and cyclonic WTs (western and southwestern IP), (3) areas in which erosion and sediment yield are controlled by easterly flows (Mediterranean coastland), and (4) lastly, a transitional zone in the inland northeast Ebro catchment, where we detected a high variability in the effects of WTs on erosion. Overall results suggest that the use of WTs derived from observed atmospheric pressure patterns could be a useful tool for inclusion in future projections of the spatial variability of erosion and sediment yield, as models capture pressure fields reliably. © 2014 Elsevier B.V., Support for this research was provided by the projects: HIDROCAES (CGL2011-27574-C02-01 and 02), INDICA (CGL2011-27753-CO2-01 and 02), and CGL2010-21754-C02-01 of the Spanish Ministry of Science and Technology funded by the Spanish Ministry of Economy and Competition and FSE. Thanks to the AEMeT for the rainfall data, and to Roberto Serrano for his helpful assistance in the precipitation analysis. Thanks to the reviewers and the editor for their detailed work to improve this article. E. Nadal-Romero was the recipient of a research contract (Spanish Ministry of Economy and Competition, Programme Juan de la Cierva), and now she is a Marie Curie postdoctoral researcher supported by the UE (project “MED-AFFOREST” PIEF-GA-2013-624974).

Halogen-free flame retardants (HFFRs), such as the aromatic organophosphorus flame retardants (OPFRs) triphenyl phosphate (TPHP), resorcinol bis(diphenylphosphate) (PBDPP) and bisphenol A bis(diphenylphosphate) (BPA-BDPP) have been proposed as potential replacements for brominated flame retardants in polymers and textiles. Although these OPFRs are already marketed, their environmental fate and effects are poorly characterised. The aim of this study was therefore to determine the mineralisation and primary biodegradation of these OPFRs by activated sludge. Mineralisation was monitored by measuring CO2 production by means of GC analysis, whereas primary biodegradation was monitored by LC-MS/MS analysis of the OPFRs and their potential metabolites. TPHP was biodegraded and mineralised most rapidly and achieved the requirement for ready biodegradability (60% of theoretical maximum mineralisation). Primary biodegradation was also rapid for PBDPP, but 60% mineralisation was not achieved within the time of the test, suggesting that transformation products of PBDPP may accumulate. Primary degradation of BPA-BDPP was very slow and very low CO2 production was also observed. Based on these results, TPHP and to a lesser extent PBDPP appear to be suitable replacements for the more environmentally persistent brominated flame retardants.

AimsTo discuss the need to develop ethical guidelines for researchers using sewage epidemiology to monitor drug use in the general population and specific precincts, including prisons, schools and workplaces.MethodDescribe current applications of sewage epidemiology, identify potential ethical risks associated with this science, and identify key means by which these risks may be mitigated through proportionate ethical guidance that allows this science to be fully developed.ResultsA rapidly advancing field of research is sewage epidemiology (SE) — the analysis of wastewater samples to monitor illicit drug use and other substances. Typically this research involves low ethical risks because individual participants cannot be identified and, consequently, review has been waived by human research ethics committees. In the absence of such oversight, ethical research guidelines are recommended for SE teams, peer reviewers and journal editors; guidelines will assist them to mitigate any risks in general population studies and studies of prisons, schools and workplaces. Potential harms include the stigmatisation of participants and, in the prison setting, austere policy responses to SE data that impact negatively upon inmate-participants. The risk of harm can be managed through research planning, awareness of the socio-political context in which results will be interpreted (or, in the case of media, sensationalised) and careful relations with industry partners. Ethical guidelines should be developed in consultation with SE scholars and be periodically amended. They should include publication processes that safeguard scientific rigour and be promulgated through existing research governance structures.ConclusionsGuidelines will assist to promote an ethical research culture among SE teams and scholars involved in the publication process and this will work to protect the reputation of the field.

This work illustrates the potential of liquid chromatography coupled to a hybrid linear ion trap Fourier Transform Orbitrap mass spectrometer for the simultaneous identification and quantification of 24 drugs of abuse and relevant metabolites in sewage water. The developed methodology consisted of automatic solid-phase extraction using Oasis HLB cartridges, chromatographic separation of the targeted drugs, full-scan accurate mass data acquisition under positive electrospray ionization mode over an m/z range of 50-600 Da at a resolution of 30,000 FWHM and simultaneous MSn measurements to obtain information of fragment ions generated in the linear ion trap. Accurate mass of the protonated molecule, together with at least one nominal mass product ion and retention time allowed the confident identification of the compounds detected in these complex matrices. In addition to the highly reliable qualitative analysis, Orbitrap analyzer also proved to have satisfactory potential for quantification at sub-ppb analyte levels, a possibility that has been very little explored in the literature until now. The limits of quantification ranged from 4 to 68 ng L−1 in influent sewage water, and from 2 to 35 ng L−1 in effluent, with the exception of MDA, morphine and THC that presented higher values as a consequence of the high ionization suppression in this type of samples. Satisfactory recoveries (70-120%) and precision (

Studies of biological responses in the terrestrial environment to rapid changes in climate have mostly been concerned with aboveground biota, whereas less is known of belowground organisms. The present study focuses on mites and springtails of heathland ecosystems and how the microarthropod community has responded to simulated climate change in a long-term field experiment. Increased temperature and repeated drought was applied for 13 years to field plots located in Wales, The Netherlands and Denmark representing sites of contrasting climatic conditions with respect to precipitation and temperature. This approach provided an opportunity to study biological responses on a local (within sites) and regional scale. Warming treatments increasing night time temperature (0.3-1 °C higher than ambient at 5 cm soil depth) had no detectable effects on the microarthropod communities. Increased intensity and frequency of drought had only weak persistent effects on springtail species composition, but practically no effect on major mite groups (Oribatida, Prostigmata or Mesostigmata) suggesting that ecosystem functions of microarthropods may only be transiently impacted by repeated spring or summer drought.

The chemical water quality is often assessed by screening for a limited set of target chemicals. This ‘conventional’ target analysis approach inevitably misses chemicals present in the samples. In this study a ‘broad’ target screening approach for water quality assessment using high resolution and accurate mass spectrometry (HR MS) was applied to detect a wide variety of organic chemicals in 42 groundwater samples. In this approach, both known and unidentified chemicals observed in previous samples define the training set for the analysis of future samples and, additionally, new samples can be used to extend the training set. Nearly 400 chemicals were observed in the samples, of which 82 were known and more than 313 are of unknown identity. The obtained results were interpreted in relation to the source characteristics and land use. Groundwater that was affected by landfills showed the highest total MS response (ion counts) and most individual chemicals and was therefore considered most contaminated. Furthermore, river bank filtrated water was generally more contaminated than phreatic groundwater and groundwater from (semi)confined aquifers was most pristine. Additionally, industrial chemicals were more frequently observed in river bank filtrated water and pesticides were more frequently observed in water originating from rural areas. The ‘broad’ target screening approach for both known and unidentified chemicals does provide more information on the over-all water quality than ‘conventional’ target analysis.

On-line thermally assisted hydrolysis and methylation (THM) in the presence of both unlabelled and 13C-labelled tetramethylammonium hydroxide (TMAH) was used to assess the relative contributions of phenolics (lignin, demethylated lignin and non-lignin phenolics) in a peaty gley soil profile beneath an unimproved grassland (LL), from a study site located at Harwood (Northumberland, northeast England, UK). This site also includes an unforested moorland (ML) and a second rotation Sitka spruce stand (SS). The common lignin proxies have been corrected for contributions of non-lignin phenols and demethylated lignin in the LL ecosystem and then compared with those from the ML and SS ecosystems. The phenolic compositions from the contributory vegetation inputs (i.e. grasses, heather and Sitka spruce) to all three soils (LL, ML and SS) were also analysed. By using 13C-labelled TMAH it was possible to show that the chemical composition of soil organic matter (SOM) reflected the different vegetation inputs in each of the L/F layers but these characteristics were lost from the deeper organic and mineral layers. Similar changes in the yield of lignin monomers (Λ) with increasing soil depth were displayed in the LL soil profile as reported previously in the ML soil in that no maxima were observed in these amount-depth profiles. The tannin input to the LL soil is low and as a consequence, unlike the ML and SS soils, there is no progressive decrease in the amounts of these non-lignin phenolics with increasing depth. Finally the methylated carbohydrate derivatives (MC) become more abundant relative to the phenolics with increasing soil depth in all three ecosystems (LL, ML and SS).

A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H2O2, activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca2+ solutions compared to similar concentrations of Na+, while that of anionic compounds is three fold weaker in SO42- solutions compared to equal concentrations of Cl-. (C) 2012 Elsevier Ltd. All rights reserved.

Acid atmospheric emissions within Europe and North America have decreased strongly since 1985 and most recent acidification studies have focused on the changes occurring within ecosystems as a result of this decreased deposition. This current study documents a soil acidification trend under ambient N deposition conditions over a 13 year period, suggesting that acidification continues to be a process of concern at this Calluna vulgaris dominated heathland with an acidic sandy soil. The annual manipulation of climatic conditions on this heathland simulated the predicted summer rainfall reduction (drought) and resulted in a long term retardation of the soil acidification trend. The pH of the soil solution significantly decreased over the course of the trial for both treatments, however, in the final two years the decline continued only in the Control treatment. This retardation is primarily associated with the reduction in rainfall leading to lower drainage rates, reduced loss of cations and therefore reduced lowering of the soil acid neutralizing capacity (ANC). However, a change in the underlying mechanisms also indicated that N transformations became less important in the Drought treatment. This change corresponded to an increase in groundcover of an air-pollution tolerant moss species and it is hypothesized that this increasing moss cover filtered an increasing quantity of deposited N, thus reducing the N available for transformation. A soil acidification lag time is expected to increase between the two treatments due to the cumulative disparity in cation retention and rates of proton formation. To the authors knowledge, this is the first study in which such acidification trends have been demonstrated in a field-scale climate manipulation experiment.

The effect of salinity induced by CaCl2, MgCl2, NaCl and Na2SO4 on the mobility of Cu, Cd, Pb and Zn was studied. An increase of ionic strength by any salts promoted a higher release of Cd than the others metals. When CaCl2 and NaCl were applied, Cd and Pb showed the highest degree of mobilization. When MgCl2 was applied, Cd and Cu were mobilized the most. Finally, an increase of Na2SO4 also promoted the strongest mobilization of Cd and Cu.As the total heavy metal content was higher, the percentage of Pb and Cu released upon salinization decreased, indicating that these metals are strongly bound to soil constituents. An increase of carbonates in the soil promoted a higher release of Pb for all used salts and for Zn when MgCl2 and NaCl were used. This indicates that Pb and Zn are adsorbed on the surface of carbonate crystals. An increase of fine particles promoted a decrease of percentage of released Cd for all salts, indicating that Cd is strongly retained in the fine fractions.The main mechanism regulating Pb and Cd mobility was competition with Ca2+ for sorption sites followed for metal chloro-complexation, association between the Cd/Pb-sulfates and competition with Mg2+. The main mechanism regulating Cu mobility was the formation of Cu-sulfate, followed by competition with cations (Mg > Ca) and chloride. For Zn, competition with Ca2+ for sorption sites was the most important process for its mobility; followed by Zn-sulfate association and, finally, chloride and competition with Mg with the same effect.

Extracellular polymeric substances (EPS) are continuously produced by bacteria during their growth and metabolism. In soils, EPS are bound to cell surfaces, associated with biofilms, or released into solution where they can react with other solutes and soil particle surfaces. If such reaction results in a decrease in EPS bioaccessibility, it may contribute to stabilization of microbial-derived organic carbon (OC) in soil. Here we examined: (i) the chemical fractionation of EPS produced by a common Gram positive soil bacterial strain (Bacillus subtilis) during reaction with dissolved and colloidal Al species and (ii) the resulting stabilization against desorption and microbial decay by the respective coprecipitation (with dissolved Al) and adsorption (with Al(OH)3(am)) processes. Coprecipitates and adsorption complexes obtained following EPS-Al reaction as a function of pH and ionic strength were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stability of adsorbed and coprecipitated EPS against biodegradation was assessed by mineralizationexperiments for 1100 h. Up to 60% of the initial 100 mg/L EPS-C was adsorbed at the highest initial molar Al:C ratio (1.86), but this still resulted only in a moderate OC mass fraction in the solid phase (17 mg/g Al(OH)3(am)). In contrast, while coprecipitation by Al was less efficient in removing EPS from solution (maximum values of 33% at molar Al:C ratios of 0.1-0.2), the OC mass fraction in the solid product was substantially larger than that in adsorption complexes. Organic Pcompounds were preferentially bound during both adsorption and coprecipitation. Data are consistent with strong ligand exchange of EPS phosphoryl groups during adsorption to Al(OH)3(am), whereas for coprecipitation weaker sorption mechanismsare also involved. X-ray photoelectron analyses indicate an intimate mixing of EPS with Al in the coprecipitates, which is not observed in the case of EPS adsorption complexes. The incubation experiments showed that both processes result in overall stabilization of EPS against microbial decay. Stabilization of adsorbed or coprecipitated EPS increased with increasing molar Al:C ratio and biodegradation was correlated with EPS desorption, implying that detachment of EPS from surface sites is a prerequisite for microbial utilization. Results indicate that the mechanisms transferring EPS into Al-organic associations may significantly affect the composition and stability of biomolecular C, N and P in soils. The observed efficient stabilization of EPS might explain the strong microbial character of organic matter in subsoils.

In this study we tested the hypothesis that water-extractable organic carbon (WEOC) content and its properties can be used to distinguish conventionally (CONV) from organically (ORG) managed arable soils as responsible for C mineralization. We sampled soils at three different European sites located in Mediterranean (Italy) and continental (Switzerland) regions under conventional and organic management. The Mediterranean sites are here called CVI and LSI and the continental one DOK. The main difference between the two management systems (ORG and CONV) at all sites was the amount of organic fertilizer yearly added into the soil: in the ORG systems 2.2-2.5 Mg C year(-1) were added as organic fertilizer, while in the CONV systems only mineral fertilizers were used. Moreover, the crop rotation was different between the two management systems at first two sites (7 years-crop vs. 4 years-crop rotation), while at DOK site a 7 years-crop rotation was adopted in both managements. In these soils we analyzed C mineralization rate expressed as percentage of mineralized C in a 90-day incubation with respect to soil total organic C (qM), the content of water-extractable organic carbon (WEOC), its initial composition by fluorescence spectroscopy (humification index - HIX) and its biodegradability (Delta WEOC). The Mediterranean basic soil accumulated more organic C showing a more complex WEOC than continental acid soil. Moreover, among management practices the crop rotation seemed to be one of the most important factor affecting WEOC properties and C mineralization rate (qM). In particular the highest qM and WEOC content were observed in both systems with 7 years-crop rotation including pasture, such as alfalfa or grass clover, according to the order ORG(DOK) = CONV(DOK) > ORG(LSI)> ORG(CVI). With respect to the effect of the management systems on C mineralization rate and WEOC properties, significant differences of WEOC content were observed between ORG and CONV soils at all sites (5.7 vs. 7.7; 14.5 vs. 17.9; 6.8 vs. 13.5 at CVI, DOK and LSI, respectively), whereas qM and HIX were significantly different only at the Mediterranean sites (qM: 4.4 vs. 5.8 and 6.6 vs. 8.2; HIX: 9.4 vs. 13.7 and 3.4 vs. 13.6 at CVI and LSI, respectively). Therefore, we can conclude that WEOC content is not a generally applicable parameter to distinguish conventionally from organically managed soils as responsible for C mineralization. Specific cropping systems, soil properties and climate conditions should be considered as important factors affecting mineralization process and WEOC properties.

article i nfo Shelf sediments of the southern North Sea, were studied with a microanalytical (electron probe X-ray microanalysis (EPXMA)) and two bulk (X-ray diffraction (XRD) and X-ray fluorescence (XRF)) techniques. The investigation proved that the promptness of the microanalytical method is combined with a reasonable analytical reliability. XRD studies of such a type of sediments with monotonous mineral composition are not able to provide mineralogical information beyond the main well-crystalline minerals and the mineralogical quantitative characteristic of the sediment based on XRD estimations are incorrect. The EPXMA mineralogical interpretations are based on the statistical evaluation of a huge data set (thousands of mineral particles) and provide a rather correct quantitative determination of the main minerals. The comparative EPXMA-XRF study revealed that the Al, Si, K, Ca, Fe and to some extent Ti contents estimated by EPXMA are fairly reliable. In this respect the accuracy of the EPXMA-based mineral identification of the pure silicates, pure aluminosilicates, and Al-, Ca-, Fe- and Ti-containing minerals with simple composition is very high. Mg- calcite, augite and apatite determinations are assessed to be correct. The supposed accuracy of the clay mineral determinations is slightly lower (70-80%) than that of the other main minerals due to the complex and varying composition of the clays. The identification of XRD-invisible accessory minerals and quantification of their presence in the sediments is an essential advantage of the EPXMA, which makes it a useful approach in tracing the origin of the sediments, the pathways of their transport and the geochemical processes they have undergone. However, the EPXMA has several flaws, which need to be solved in the future sediment investigations: (1) calibration with natural standards is needed in order to provide a higher accuracy of the mineral determinations; (2) any EPXMA study of sediments needs to be secured with XRF examinations of selected samples since EPXMA gives only semi-quantitative information about the abundance of the elements; (3) ultra-thin window EPXMA of low-Z elements has to be used since some of them (O, C) are always present in the main sediment components: silicates, aluminosilicates, carbonates and metal oxyhydr- oxides; (4) the interpretations of the clay fraction have to be supported with detailed XRD investigations of selected samples, while the mineralogy of the silt and sand fractions needs to be backed up with optical microscopy studies. The information from different analytical techniques (EPXMA with XRF-XRD-optical microscopy of selected samples) combined with the knowledge about the most possible minerals in a given environment, would give the most reliable results in studying mineralogical composition of shelf sediments.

The volcanic ash soils in the Guandera region in northern Ecuador exhibit a typical accumulation of organic matter. However, while accumulated, the organic matter present in the mineral soil bears hardly any resemblance with the covering vegetation and its litter. A strong degradation of the ligno-cellulose complex and a large accumulation of aliphatic components were the main characteristics. The accumulation of aliphatic moieties coincided with an excellent preservation of the solvent extractable n-alkanes and n-alcohols as evidenced by large carbon preference indexes (CPIs) and, consequently, a typical plant-derived signature. Although well-preserved, the n-alkanes underwent β-oxidation yielding n-methyl ketones in a somewhat different distribution. The differences observed between n-alkanes and n-methyl ketones were attributed to a relatively more rapid oxidation of alkanes derived from the grass Calamagrostis effusa as compared to the more woody roots of Neurolepis aristata. From top to bottom of the profile, and therefore with time, all lipid signals had rather similar compositions with limited (microbial) degradation implying their significant value as potential biomarkers.

To assist sustainable reforestation efforts in the Andes in Northern Ecuador, the position of the natural upper forest line (UFL) has to be assessed. To this end, new vegetation reconstruction techniques to complement traditional reconstruction methods such as pollen analysis are being developed. One such technique is the biomarker ratio approach that uses changes in characteristic ratios of extractable lipids, such as n-alkanes and n-alcohols for a quick assessment at high spatial resolution of abrupt past vegetation changes. In the present study we assessed the applicability of this approach as indicator of past vegetation shifts from forest to páramo or vice versa in Northern Ecuador. We looked at the n-alkane and n-alcohol signals of two soil monoliths, one taken in a forest patch located 100 m above the current UFL, and the other at the same altitude in the surrounding páramo. The monoliths were sampled to a depth corresponding to at least 1500 cal yr BC. Links were sought between biomarker ratio signals in soil organic matter (SOM) and those found in plants from the vicinity during previous research. Based on the outcome an attempt was made at determining whether the forest patch had been part of the continuous forest further down slope during the last 3500 cal years. Results show that specific ratios of extractable straight-chain lipids can be used to get a quick indication of whether an area was forested or not in the past. In SOM the n-alkane relationship C29/C31 > 1 combined with the n-alcohol relationship C22/C24 < 1 was found to be characteristic for dominant forest vegetation, while the opposite relationships were indicative for past páramo vegetation. The n-alkane relationship could be explained very well by the lipid ratios of the current forest and páramo vegetation in the area. While agreeing well with the n-alkane signal, the n-alcohol signal was less robust, probably partially due to degradation of wax esters in the soil. Contrary to expectations, we conclude that the investigated forest patch was never part of the continuous forest in the vicinity in the past 3500 cal years. Instead our biomarker ratio approach suggests that the forest patch soil was once covered by páramo vegetation. Overall, this study shows that the biomarker ratio approach in volcanic ash soils can serve as a quick method for an assessment of abrupt vegetation changes such as associated with past UFL shifts at a high spatial resolution and at the location where the shift occurred. As such it is highly complementary to traditional proxies such as pollen analysis.

As part of a longitudinal cohort study, now in its second decade, we determined PCDDs/Fs dl-PCBs and PBDEs in serum of adolescents with known perinatal PCDD/F exposure. Of the original cohort, 33 adolescents aged 14-19 years, who had been studied previously during their neonatal (n=60), toddler and pre-pubertal period (n=41) agreed to participate in the current follow-up. PCDD/F-, dl-PCB- and PBDE congeners were measured using GC/MS. Current serum levels of PCDD/Fs determined in our cohort were relatively low (mean of 2.2 pg/g) compared to the perinatal exposure. No correlation between perinatal exposure and current serum PCDD/F was found. Planar PCB TEQ levels were 2.2 pg/g. Current summation operatorPBDE levels were 8.7 ng/g lipid. There was one outlier with a summation operatorPBDE of 74 ng/g lipid. The presence of this high value indicates that the exposure pathway is different from PCDD/F and PCB, most likely by dust and food contaminated with dust. Concluding we can say that current PCDD/F levels are quite low compared to the perinatal PCDD/F exposure of the cohort. PBDE levels however are relatively high compared to other European countries, more research on possible health effects of these levels, especially for subjects with outlier concentrations, should be performed.

Objectives: While many studies have assessed the health impacts of PCDD/Fs and PCBs on animals and humans, long-term consequences for especially adolescents, have not (yet) been well documented. This is certainly also true for the effects of PBDE exposure. As part of a longitudinal cohort study, now well into its second decade, effects of perinatal and current PCDD/F exposure, as well as current dl-PCB and PBDE exposures, on puberty, were assessed. Study design: Prenatal, lactational and current PCDD/F, dl-PCB and PBDE concentrations were determined using GC-MS. Pubertal development and growth were assessed by means of physical examination and the Tanner scale. 33 Children (born between 1986 and 1991) consented to the current follow-up study. Outcomes were evaluated using linear regression or the non parametric Spearman's correlation coefficient. Results: A delay in initiation of breast development was found in girls (n = 18) with higher prenatal (p 0.023) and lactational PCDD/F exposure (p = 0.048). The males revealed a negative trend with age at first ejaculation. For other endpoints on puberty and growth (pubic hair, axillary hair, genital stage, length, BMI, testicular volume, merino significant relation was found with any of the measured compounds. Discussion and conclusion: A relation between prenatal PCDD/F exposure and later initiation of breast development was seen. A Belgian study found a delay in breast development with higher current serum concentrations of dioxin-like compounds. The initiation of puberty is a complex process and it is yet not clear how dioxin-like compounds precisely affect this process prenatally. Further follow-up into adulthood is warranted, in order to detect the possibility of developing malignancies and fertility problems. (c) 2008 Elsevier Ltd. All rights reserved

Photosynthetically fixed CO 2 is converted into terrestrial bio(macro)molecules and sequestered as soil organic matter (SOM) by (bio)chemical and physical stabilization processes. SOM is generally divided in arbitrary pools for modeling SOM dynamics. Biochemically recalcitrant SOM fractions are enriched with alkyl carbon (C) structures and resist decomposition due to intrinsic molecular properties. The proportion of alkyl C and the mean age of SOM increase with increase in soil depth. Precursors of these recalcitrant bio(macro)molecules such as glycerides, waxes, and terpenoids occur in plants, microorganisms and animals. The intrinsic biochemical stability of naturally occurring recalcitrant aliphatic biomacromolecules may enhance the terrestrial storage of atmospheric CO 2 . Also, aliphatic macromolecules may be formed in soils upon non-enzymatic polymerization of low-molecular-weight lipids. In this review we propose that increasing the soil organic carbon (SOC) pool by land-use and management practices should also include strategies to increase the proportion of aliphatic compounds in the belowground biomass. Thus, collaborative research is needed to study the fate of plant-, microbial- and animal-derived aliphatic C as precursors for stabilized aliphatic SOC fractions, in particular in deeper soil horizons.

Pioneer plant species were observed growing on mined areas despite unfavourable conditions such as extreme pH, high salinity and phytotoxic levels of several elements. This study evaluated the contribution of pioneer species to the accumulation of soil organic matter (SOM). We collected 51 samples from 17 non-vegetated, natural and pioneer-vegetated sites in five highly saline mined areas in the Sierra de Cartagena (Spain). The composition of SOM was determined using total C, N and S elemental anlayzer, pyrolysis and solid state (13)C NMR spectroscopy. Results showed that pioneer species like Lygeum spartum had contributed approximately 11 kg SOM kg(-1) soil into the Balsa Rosa sites since 1991; it will take approximately 120 years of continuous growth for this plant to increase the SOM level comparable to natural site. In the Portman Bay area, Sarconia ramosissima and Phragmites australis can contribute SOM equivalent to present day SOM in natural sites in the next 30 years. Low quality SOM (C/N>20) deposited by pioneer plants was dominated by lignin-derived organic compounds such as phenols, guaiacols, syringols and aromatics while polyssacharides and alkyls were the major components in high quality SOM (C/N

Condensed tannins are a major component of litter inputs, but little is known about the effects of tannin structural variations on soil biological processes and organic matter development. Four different condensed tannins (CTs) extracted from balsam fir, western red cedar, kalmia and black spruce were added to Corsican pine litter and subsequently incubated for 16 weeks in order to investigate the effect of the B ring hydroxylation pattern on C, N and P transformations. While for C mineralization the chain length and stereochemistry of the CTs seemed to be a more important parameter, net N and P mineralization rates were clearly reduced compared with non-amended litter. With regard to the B ring hydroxylation, the prodelphinidin (PD) CTs having predominantly three hydroxy groups at the B ring (balsam fir and western red cedar) exhibited significantly lower mineralization rates than the procyanidin (PC) CTs having two OH groups (kalmia and black spruce). The same was true for net nitrification, but this process was only slightly affected by the CTs. Although based on only four CTs, this study indicates that B ring hydroxylation is an important variable determining net N and P mineralization rates. Our results support previous suggestions that PD tannins bind to or react more strongly with soil organic matter. Therefore, more than PC tannins, they reduce the availability of organic N for mineralization as well as their own detectability by standard methods for soil CT.

Results are presented of a field study in the Dutch coastal zone of the North Sea on the environmental fate of nonylphenol ethoxylates (A9PEO). The goal of this field study was to determine the sources of these nonionic surfactants to the Dutch coastal zone, and their subsequent fate. Surface waters, sediments and suspended particulate matter were analyzed on A9PEO, nonylphenol (NP) and the carboxylated metabolites (A9PEC), using Soxhlet extraction, Solid Phase Extraction and liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS). Unusually high dissolved concentrations of A9PEO were observed in a number of offshore samples. Maximum dissolved concentrations of 36, 1.7 and 0.63 μg L−1 were observed, respectively, for A9PEO, NP and A9PEC. Dissolved concentrations of A9PEO at the water surface were roughly one order of magnitude higher than several meters below the surface. More than 25% of the A9PEO present in marine water is sorbed to suspended particulate matter. In sediments, maximum concentrations of 277 and 86 ng g−1 for A9PEO and NP were observed, whereas A9PEC were only found sporadically. Relatively high concentrations of A9PEO and NP were observed in sediments near the shore, which decreased until below 50 ng g−1 d.w. at about 10 km off shore. In the sediments, mainly the short chain A9PEO1–3 are detected, indicating that extensive biodegradation has occurred. Both the oxidative and non-oxidative hydrolytic biodegradation mechanisms occur in the Dutch coastal zone, although the oxidative route is less important than in the adjacent Scheldt and Rhine estuaries. The main sources of A9PEO in sediments in the Dutch coastal zone were identified as the Rhine and Scheldt estuaries, dump sites for harbour dredge and in some cases production platforms. For the water phase, the most likely sources of A9PEO seem to be discharges from ships at open sea.

Total lipid extracts (TLEs) of subsoils from under oak, had been subjected to natural acidification, were analysed to trace the effects of soil pH on their composition. In addition, roots were analysed as being the main source of SOM in the deeper mineral soil horizons. The TLE of the roots comprised largely triterpenoids and steroids that were barely present in the subsoils. Conversely, only small amounts of alkanoic acids, and no alkanols, ω-hydroxyalkanoic acids or α,ω-alkanedioic acids were detected in the root TLE, whereas in soil TLEs these compounds were highly abundant. The compounds are suggested to be derived from hydrolysed suberin, from the previous grass vegetation and most likely illuviated lipids (i.e. immobilised lipids that moved downwards in dissolved form from overlying horizons) from upper, organic matter-rich horizons and oxidation of lipids mediated by microorganisms. In the course of the soil acidification the amounts of TLE increased and within this fraction long-chain (>C20) alkanoic acids, alkanols, ω-hydroxyalkanoic acids and α,ω-alkanedioic acids increased relatively with respect to short chain (

The acreage of rainfed almond plantations (Prunus dulcis (Miller)) in Spain has rapidly increased during the last 30 years, reflecting a tendency towards specialisation in perennial, rainfed crops in many Mediterranean regions. Seminatural vegetation and diverse cropping systems have been converted into monocultures with low tree densities leaving the soil unprotected. This paper illustrates the contrast in water conservation strategies between traditional and modem almond plantations in the Murcia region (Spain), and highlights the impacts of intensification on soil degradation. The role of lateral and vertical redistribution of soil moisture in water conservation will be discussed based on the analysis of soil moisture retention characteristics, temporal variation in soil moisture content and soil moisture patterns. A traditional cereal/almond cropping system typical for mart areas with a subdued relief will be compared to a modem almond monoculture in a highly dissected landscape on slate bedrock. The low water holding capacity of the stony soil in the slate area caused rainfall to penetrate deep in the profile and thus soil moisture fluxes were mainly vertical. Semivariograms of topsoil moisture content after an isolated rain day (19 and 27 mm for the nearest raingauges) demonstrated the differences in lateral redistribution of soil moisture between the cropping systems. A spatial pattern in the mart soil with a range of 69 m was observed, whereas soil moisture in the slate area showed no spatial pattern except for higher values in the narrow valley bottom. The scarcity of rainfall producing lateral redistribution of soil moisture explained the lack of reliable moisture supply in the mart area. This led to very low overall plant densities at 16 trees ha(-1), restricted to wetter zones upstream of retention dams. The redistribution of soil moisture by vertical fluxes in the stony soils of the slate area explained the uniform, widely spaced trees at densities of 204 trees ha(-1). This study has highlighted the need for rainfall to penetrate deep into the soil to sustain almond monocultures in semiarid climates. However, this requires a loose, bare topsoil between the trees and thus large areas of bare soil are exposed on hillslopes resulting in high erosion risks. (C) 2002 Elsevier Science B.V. All rights reserved.

Subsurface horizons contain considerable amounts of soil organic matter (SOM), which has generally a relatively recalcitrant nature and may be an important key in the examination of the role of soils in the sequestration of carbon. Nonetheless, this part of SOM is hardly studied. This paper focuses on the effects of soil acidification on the formation of SOM in sandy subsurface horizons under Corsican pine ( Pinus nigra var. maritime ) and common oak ( Quercus robur L.) forests in coastal dunes (The Netherlands) as characterized by pyrolysis and thermally assisted hydrolysis and methylation. In the pine forests of 50–70 y old SOM appeared to be only slightly affected by soil pH, whereas SOM from oak forests (100–200 years) showed pronounced changes upon soil acidification. With decreasing soil pH in the oak forests, lignin was more degraded (decrease in syringyl/guaiacyl ratio, reduction of the relative concentration) and the contribution of suberin-derived aliphatic moieties increased. The latter compounds may therefore play an important role in the formation of SOM in the studied subsoils.

The (subcooled) liquid vapour pressure, heat of vapourization and gas-liquid heat capacity difference of monoterpenes and biogenically related compounds were determined by a gas-liquid chromatographic method based on Kovats retention indices. Compared to those used in previous studies using the same method, these compounds are structurally diverse and have relatively low boiling points. Despite of this and even though the difference in activity coefficients in the chromatographic column stationary phase between the test and reference compounds were ignored, results for vapour pressure compare favorably with experimental literature data. The results indicate that the method can be improved by introducing temperature dependent activity coefficients, preferably based on a physicochemical model for gas-liquid partitioning.

Differences in soil organic matter (SOM) composition in consecutive soil profiles (under algae, grass, moss, heather and pine) from a primary vegetation succession (central Netherlands) were investigated by Cross Polarization-Magic Angle Spinning (CPMAS) 13C NMR, chemical degradation (acid hydrolysis of polysaccharides) and pyrolysis-GC/MS (Py-GC/MS) in relation to the vegetation. All mineral soil horizons had lower contents of polysaccharides than the ectorganic layer and/or the fresh plant material as suggested by the diminishing O-alkyl peaks by NMR. The monosaccharide distribution pointed to an increase of microbial sugars in the soil as suggested by the raising C6/C5 ratios. Soil polysaccharides may be accompanied by a significant contribution of carbohydrates from mosses in the first stages, because the undecomposed moss tissues have high C6/C5 ratios, which falsify the usual interpretation that such high ratios may be due to microbial sugars. Fresh litter and ectorganic layers under heather and pine had similar contents of aromatics, but the contribution of lignin (guaiacols and syringols) was lower in the ectorganic horizons. The degree of oxidation, as determined by the acid/aldehyde ratio, increased with progressive humification. All Ah horizons contained less aromatics, more oxidized lignin remnants and higher amounts of aliphatic compounds than the litter. One or two macromolecules, which produced n-alkenes/n-alkanes and branched alkenes/alkanes upon pyrolysis and were derived from mosses, were mainly responsible for the accumulation of aliphatics in soil, although other aliphatic polymers, such as suberin, might also play an important role. Preservation of components from earlier vegetation might significantly influence SOM composition.

Soil aggregation in relation to other soil properties was studied along a climatological transect in the Southeast of Spain. Three sites were selected along this transect ranging from semiarid to subhumid climatological conditions. The aggregate size distribution, the macro and microaggregate stability of the superficial soil horizon and their relations with other soil properties were analysed. Large aggregates (>10, 10–5, 5–2 mm) were present in highest proportions in the most arid of the studied areas. These large aggregates were associated with high values of water-stable microaggregates; however, they did not improve soil structure and are related to high bulk densities and low water retention. Aggregates 1–0.105 mm were positively correlated to medium, fine, very fine sand and silt fractions and to organic matter. Aggregates Water stability of microaggregates showed a positive correlation with clay content while the stability of the macroaggregates depended on the organic matter content when the organic matter content was greater than 5 or 6%. Below that threshold the carbonate content was strongly correlated with aggregate stability. A general conceptual scheme of associations between aggregate size distribution, water-stable microaggregation and textural characteristics for the area was developed. The land use history affecting soil overlaps the pattern of climatological situations and has to be taken into account. Aggregate size distribution and stability can be used as indicator of soil degradation, but not as a unique parameter.

This chapter describes the historical development and present applications of water-quality models for organic chemical compounds (e.g., polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)). Various types of water-quality models are described, varying in the amount of compartments, in spatial dimension, and in time. Special attention is given to the processes acting on these chemical compounds (e.g., volatilization and decomposition) and to the quality and precision of the value of parameters in these processes. An overview is given of the most important water-quality models in use now.The chapter concludes with attention and discussion points on accuracy and precision of model predictions and how to use these models for hazard and risk assessment. At the end, recommendations are presented for improving the further development and application of water-quality models by benchmarking and monitoring.

Changes in climate or forest management practices leading to increased litter production will most likely cause increased leaching rates of dissolved organic carbon (DOC) from the O horizon. The rhizosphere is often assumed to have a large carbon flux associated with root turnover and exudation. However, little has been done to quantify the amount of DOC originating from root litter. We studied decomposition of fine root and needle litter of Norway spruce (Picea abies) through a combined incubation and leaching experiment in the laboratory using five different litter types: fresh needle litter, aged needles from the litter layer, fresh and dead roots from mineral soil samples, and seven-year-old roots from a previous litterbag study. After respiration measurements, the samples were percolated with artificial throughfall water and DOC and UV absorbance were measured in the leachate. Mineralisation of dissolved organic matter in the leachate and sorption of DOC to ferrihydrite were determined as a measure of DOC ability to be stabilised by iron (hydr)oxide surfaces.The mineralisation rate and DOC production rate of root samples were always lower than that of needle samples. However, root and needle derived dissolved organic matter (DOM) were similar in terms of aromaticity, as indicated by their specific UV absorbance, and ability to be sorbed by ferrihydrite. For seven-year-old roots, a significantly higher fraction of carbon was lost as DOC (30%) than for younger roots (20%). Furthermore, DOM from old roots bound more strongly to ferrihydrite and is mineralised at a lower rate than DOC from younger roots, suggesting that roots at late stages of decomposition, although a small fraction of total litter, significantly contribute to carbon build-up in mineral soils. The slower decomposition rate of roots compared with needles must be taken into account when modelling litter decomposition.

11 pages, 8 figures, 3 tables, 58 references., The application of lime in a mature Norway spruce (Picea abies [L.] Karst.) forest in southern Germany induced major changes in the activity of soil organisms and root growth. Since this may influence the chemical compostion of the soil organic matter (SOM) of the organic surface layer, its composition and changes due to the treatment were examined in this study. Fine roots of Norway spruce have a relatively low content of extractable lipids, a low alkyl C content (13C CPMAS NMR) and a high ratio of non-cellulosic to cellulosic carbohydrates (NC/CC, carbohydrate determination by MBTH and gas chromatography analyses) as compared to needles. Furthermore, they show high ratios of suberin/cutin compounds (thermally assisted hydrolysis and methylation, (THM)) and high ratios of eicosanic acid/phytadiene I in their lipid extracts (pyrolysis-GC/MS). Liming (4 t ha21 dolomite) of a Norway spruce organic surface layer decreased the proportion of alkyl C, the alkyl C/O-alkyl C ratio, and the content of extractable lipids. The NC/CC ratio and the abundance of suberin relative to cutin components increased. The contribution of the chlorophyll component phytadiene I decreased in relation to eicosanic acid. These changes are attributed to increased fine root formation in the organic layer after liming. Furthermore, the presence of less degraded lignin (THM, peak ratio of 3,4-dimethoxybenzoic acid, methyl ester/3,4-dimethoxy-benzaldehyde) on the limed plot is explained by the increased input of relatively fresh fine root material. On the other hand, the decrease in the carbon-to-nitrogen ratio may be attributed to the higher microbial activity after liming., This part of the Hoeglwald research was supported by the Ministry for Education and Science, Germany, and by the European Community activity Large-Scale Facility Wageningen NMR Centre (ERBFMGECT950066).