Dynamic behaviour of 1-aminopropan-2-one in sewage: a preliminary synthetic and spectroscopic study

A preliminary investigation of the solution phase behaviour of the biomarker compound 1-aminopropan-2-one (APR) using NMR spectroscopy was carried out. This was achieved, in part, by synthesis of APR with¹³C-enrichment in the methylene position. In this paper, we report that this biomarker undergoes H/D exchange with D₂O, probably via an enol intermediate. In addition, use of¹³C-enriched APR enabled its detection by¹³C NMR spectroscopy at environmentally relevant concentrations.     

A new approach to estimate nuclide ratios from measurements with activities close to background

Measurements of low-level radioactivity often give results of the order of the detection limit. For many applications, interest is not only in estimating activity concentrations of a single radioactive isotope, but focuses on multi-isotope analyses, which often enable inference on the source of the activity detected (e.g. from activity ratios). Obviously, such conclusions become questionable if the measurement merely gives a detection limit for a specific isotope. This is particularly relevant if the presence of an isotope, which shows a low signal only (e.g. due to a short half-life or a small transition probability), is crucial for gaining the information of interest.     

玉米种子的DNA指纹计算机化鉴定

对１２个优良玉米自效系的ＤＮＡ进行了ＲＡＰＤ分析,共筛选了２５０个Ｏｐｅｒｏｎ引物,其中１２个引物共扩增出５９个多态性产物,根据这５９个多态性ＲＡＰＤ产物,对１２个自交系进行了聚类分析,把它们分为３个群,结果与根据系谱法的聚类结果一致。经过优选,用ＯＰＮ－１１扩增出的１１种ＤＮＡ带,建立了这１２个自交系的ＲＡＰＤ－ＤＮＡ指纹图谱。在该图谱呼弱个自交系都具有特异的ＤＮＡ指纹,可以与其它自效纱相区别。     

Reproduction by subordinates in cooperatively breeding Arabian babblers is uncommon but predictable

In a genetic analysis of the mating system of cooperatively breeding Arabian babblers (Timalidae: Turdoides squamiceps), we identified which individuals in the population are breeding, and how reproductive success was distributed among group members with respect to their dominance rank, for both males and females. The population was characterized by an asymmetrical distribution of reproductive success; behaviorally dominant males produced 176 of 186 (95%) of the offspring in 44 social groups analyzed, and alpha females produced 185 of 186 (99.5%). We evaluated models of reproductive skew by examining genetic and demographic correlates of reproduction by␣subordinates. Subordinate (beta) males that sired young were more likely to be recent dispersers from their natal groups or members of newly formed groups than betas that did not reproduce. Breeding beta males had spent smaller proportions of their lives with the current alpha male and female as alphas than had beta males that did not sire young. One consequence of the linkage of dispersal with breeding in newly formed, nonnatal groups is that beta males that sired young had significantly lower genetic similarity to the alpha males in their groups (based on band-sharing coefficients using multilocus minisatellite DNA fingerprinting) than those that did not sire young. This pattern may occur generally in species in which group membership accrues both through nondispersal of young (forming groups of relatives) as well as through dispersal involving coalitions that sometimes include nonrelatives. Received: 22 July 1997 / Accepted after revision: 5 February 1998     

同位素技术在环境科学研究中的应用进展

综述了近年来同位素技术在国内外环境科学研究中的应用状况,简要介绍了同位素技术的应用原理与分析方法。总结了放射性同位素技术和稳定同位素技术在环境史重建、污染物示踪及源解析等方面的应用,重点介绍了稳定同位素技术在水、大气和土壤污染物源解析中的应用进展。对未来同位素技术在环境科学研究中的应用进行了展望,提出了多种同位素联合解析、建立和完善定量源解析模型等建议。     

Application of an early warning indicator and CaO to maximize the time–space-yield of an completely mixed waste digester using rape seed oil as co-substrate

In order to increase the organic loading rate (OLR) and hereby the performance of biogas plants an early warning indicator (EWI-VFA/Ca) was applied in a laboratory-scale biogas digester to control process stability and to steer additive dosing. As soon as the EWI-VFA/Ca indicated the change from stable to instable process conditions, calcium oxide was charged as a countermeasure to raise the pH and to bind long-chain fatty acids (LCFAs) by formation of aggregates. An interval of eight days between two increases of the OLR, which corresponded to 38% of the hydraulic residence time (HRT), was sufficient for process adaptation. An OLR increase by a factor of three within six weeks was successfully used for biogas production. The OLR was increased to 9.5 kg volatile solids (VS) m^?3 d^?1 with up to 87% of fat. The high loading rates affected neither the microbial community negatively nor the biogas production process. Despite the increase of the organic load to high rates, methane production yielded almost its optimum, amounting to 0.9 m³ (kg VS)^?1. Beneath several uncharacterized members of the phylum Firmicutes mostly belonging to the family Clostridiaceae, a Syntrophomonas-like organism was identified that is known to live in a syntrophic relationship to methanogenic archaea. Within the methanogenic group, microorganisms affiliated to Methanosarcina, Methanoculleus and Methanobacterium dominated the community.     

Fingerprinting and Groundwater Model Application to Evaluate Hydraulic Barrier Efficiency (Italy)

Remediation actions at contaminated sites are based on multiple numerical model scenarios considering different parameter distributions, source positions and contaminant transport paths. In some cases the excess of scenarios is due to uncertainties in the conceptual model as a result of the spread of contamination through heterogeneities in the physical system. Reduction of project hypotheses and conceptual model uncertainty is therefore needed. This result can be achieved by coupling hydrogeological investigations with environmental forensic techniques, better localization of the source and understanding of contamination history. In this respect, in the present study, compositional fingerprinting and groundwater flow modeling were applied to a former oil storage facility where, even though a hydraulic barrier had been built to stop the hydrocarbon plume, the presence of some hydrocarbons was still found in downgradient monitoring wells. The final aim was to evaluate the efficacy of the hydraulic barrier and identify of the source of pollution. Fingerprinting results indicated pollution with a gasoline-diesel mixture much altered by water washing and/or biodegradation. Comparison of seven groundwater samples collected in wells and monitoring wells was performed by analyzing the volatile fraction (BTEX) and the total ion chromatogram (TIC), focusing attention on: n-alkanes (m/z 85), alkylcyclohexanes (m/z 83), isoprenoids (m/z 113), C4-alkylbenzenes (m/z 134), C3-C6 alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs). The most probable scenario was then identified by combining the results of fingerprinting with different contaminant paths obtained using the numerical model.     

Applications of isotope differentiation for metabolic studies with di‐(2‐ethylhexyl) phthalate

Abstract

The pervasiveness of the plasticizer di‐(2‐ethylhexyl) phthalate (DEHP) in the environment and especially in the laboratory results in a background that may cause severe interference with analytical studies. Animal‐to‐animal variability in the distribution of DEHP metabolites in excreta normally makes it necessary to use large groups of animals when different treatments are compared. Finally, radioactive tracers are usually considered undesirable for metabolic studies involving human subjects. All of these problems can be overcome through the use of muliple isotopic labels, especially ¹²C/¹³C/¹⁴C. Examples are given involving rats and monkeys, and applicability to humans is discussed. The principles involved are not limited to any particular class of test compounds. In rats, the competing pathways for metabolism of phthalate esters produce a different distribution of metabolites from a small intravenous dose of DEHP than from a large oral dose.     

Elements Influencing Cost Allocation in the Pinal Creek Aquifer,Arizona, USA. Part I: Geochemical Fingerprinting and Source Delineation

This is the first in a three-article series in this volume of Environmental Forensics describing the framework that was developed to quantitatively allocate mass loading of metals to the Pinal Creek alluvial aquifer. This article describes geochemical fingerprinting, followed by spatial and temporal analysis of Pinal Creek monitoring well data (more than 600,000 records from hundreds of locations), which identified three distinct source areas and plumes on the basis of facility-specific differences in process geochemistry, ore mineralogy, and solution handling. The primary Webster Lake/Gulch source originated in 1926 (700 mg/L chlorine, 200 mg/L copper, 3000–9000 mg/L iron). Secondary contributions from the Bluebird/Oxhide/Live Oak Gulch/Davis Canyon leach complex in Upper Bloody Tanks Wash began circa 1962 (30–200 mg/L chlorine, 1500–3500 mg/L copper, <500 mg/L iron), and recent (1992–2001) contributions came from Miami Unit hydromining releases to Bloody Tanks Wash (30–70 mg/L chlorine, ～1000 mg/L copper, ～2000 mg/L iron). In Kiser Basin, where the plumes commingle, temporal evolution of the plume chemistry is reflected in a shift from a predominantly iron:copper-rich solution (10:1) to an increasingly copper-dominated signature (1:1) with the arrival of the secondary plume. Based on historical records and geochemical fingerprints, the original acid front migrated through the alluvium at ～0.5 m/day; however, later acidic releases traveled at ～2.3 m/day due to exhaustion of the available buffering capacity. The divisible nature of the plume supports quantitative allocation of contributions to the aquifer.     

Hydrogeological and biogeochemical constrains of arsenic mobilization in shallow aquifers from the Hetao basin, Inner Mongolia

Little is known about the importance of drainage/irrigation channels and biogeochemical processes in arsenic distribution of shallow groundwaters from the Hetao basin. This investigation shows that although As concentrations are primarily dependent on reducing conditions, evaporation increases As concentration in the centre of palaeo-lake sedimentation. Near drainage channels, groundwater As concentrations are the lowest in suboxic-weakly reducing conditions. Results demonstrate that both drainage and irrigation channels produce oxygen-rich water that recharges shallow groundwaters and therefore immobilize As. Groundwater As concentration increases with a progressive decrease in redox potential along the flow path in an alluvial fan. A negative correlation between SO₄²⁻ concentrations and δ³⁴S values indicates that bacterial reduction of SO₄²⁻ occurs in reducing aquifers. Due to high concentrations of Fe (>0.5 mg L⁻¹), reductive dissolution of Fe oxides is believed to cause As release from aquifer sediments. Target aquifers for safe drinking water resources are available in alluvial fans and near irrigation channels.