Multi tracer test for the implementation of enhanced in-situ bioremediation at a BTEX-contaminated megasite

At the Centre for Environmental Research Leipzig-Halle (UFZ) research site in Zeitz, Germany, benzene contaminates the lower of two aquifers with concentrations of up to 20 mg/l. Since the benzene plume has a minimum length of approximately 1 km, enhanced natural attenuation measures are being considered as a remediation strategy. This study describes the performance and evaluation of a multi-species reactive tracer test using the tracers fluorescein and bromide as conservative tracers and toluene as reactive tracer. Sampling was performed over a period of six months using a detailed network of multilevel sampling wells. Toluene was only slightly retarded in comparison to bromide, whereas fluorescein was retarded considerably stronger. Therefore, it was not possible to use fluorescein as an in situ tracer for the determination of groundwater velocities. The ionic nature of fluorescein is assumed to be the major reason for its retardation. The results show that the infiltration conditions were suitable to produce a wide spreading of the tracer front along the full thickness of the aquifer. Thus, a large aquifer volume can be treated in future enhanced bioremediation measures. The total quantity of infiltrated toluene (24 l) was degraded under sulfate-reducing conditions over a flow path of 50 m. Benzylsuccinate was identified as a metabolite of toluene degradation under sulfate-reducing conditions at this site. The modelling results show that toluene degradation was described more accurately using Monod kinetics than first-order kinetics. Since toluene was only slightly retarded in comparison to bromide, sorption and desorption processes were considered to be negligible.     

Prenatal DNA diagnosis of Noonan syndrome in a fetus with massive hygroma colli,pleural effusion and ascites

Prenatal molecular genetic diagnosis for Noonan syndrome I is reported. Noonan syndrome was suspected because of large cystic hygroma colli, massive pleural effusion and ascites at 23 weeks of gestation and normal karyotype (46,XX). DNA was prepared from amnion cells and screened for mutations in the PTPN11 gene. In exon 8, a missense mutation (S285F) was found. Delivery was induced at 33 weeks of gestation because of silent cardiotocography (CTG). Despite immediate drainage of the hydrothorax, mechanical ventilation was insufficient and the child died 9 h after birth due to severe pulmonary hypoplasia. Pleural punctate was enriched for small lymphocytes and thus was characterized as chylus. Prenatal ultrasound findings in Noonan syndrome usually are unspecific and rarely lead to a diagnosis. However, with the combination of cystic hygroma, pleural effusion, ascites and normal karyotype Noonan syndrome should be considered and DNA testing for PTPN11 mutations may be appropriate. Malformations of lymphatic vessels and/or chylothorax in Noonan syndrome seem to be more frequent than usually anticipated. Copyright © 2005 John Wiley & Sons, Ltd.     

Project house water: a novel interdisciplinary framework to assess the environmental and socioeconomic consequences of flood-related impacts

Protecting our water resources in terms of quality and quantity is considered one of the big challenges of the twenty-first century, which requires global and multidisciplinary solutions. A specific threat to water resources, in particular, is the increased occurrence and frequency of flood events due to climate change which has significant environmental and socioeconomic impacts. In addition to climate change, flooding (or subsequent erosion and run-off) may be exacerbated by, or result from, land use activities, obstruction of waterways, or urbanization of floodplains, as well as mining and other anthropogenic activities that alter natural flow regimes. Climate change and other anthropogenic induced flood events threaten the quantity of water as well as the quality of ecosystems and associated aquatic life. The quality of water can be significantly reduced through the unintentional distribution of pollutants, damage of infrastructure, and distribution of sediments and suspended materials during flood events. To understand and predict how flood events and associated distribution of pollutants may impact ecosystem and human health, as well as infrastructure, large-scale interdisciplinary collaborative efforts are required, which involve ecotoxicologists, hydrologists, chemists, geoscientists, water engineers, and socioeconomists. The research network “project house water” consists of a number of experts from a wide range of disciplines and was established to improve our current understanding of flood events and associated societal and environmental impacts. The concept of project house and similar seed fund and boost fund projects was established by the RWTH Aachen University within the framework of the German excellence initiative with support of the German research foundation (DFG) to promote and fund interdisciplinary research projects and provide a platform for scientists to collaborate on innovative, challenging research. Project house water consists of six proof-of-concept studies in very diverse and interdisciplinary areas of research (ecotoxicology, water, and chemical process engineering, geography, sociology, economy). The goal is to promote and foster high-quality research in the areas of water research and flood-risk assessments that combine and build off-laboratory experiments with modeling, monitoring, and surveys, as well as the use of applied methods and techniques across a variety of disciplines.     

The Swedish System for Quality Assessment of Agricultural Soils

Soil quality assessment is based on the concept of soilfunctions. The performances of three soil functions, cropproduction, biological decomposition and matter exchange withthe atmosphere and groundwater, are used as quality criteria.Soil properties that can be used as indicators for the degreeof functional performance were identified. Each soil propertyselected was graded into five classes – from best (class 1) toworst (class 5). Grading was based biological on boundaryconditions as well as on statistical distribution. The systemoutlined can be used to interpret the quality state ofagricultural soils, provides for a relative comparison betweensoils, and may be helpful in an environmental monitoringprogram to assess trends in data.     

Mobility of organic carbon from incineration residues

Dissolved organic carbon (DOC) may affect the transport of pollutants from incineration residues when landfilled or used in geotechnical construction. The leaching of dissolved organic carbon (DOC) from municipal solid waste incineration (MSWI) bottom ash and air pollution control residue (APC) from the incineration of waste wood was investigated. Factors affecting the mobility of DOC were studied in a reduced 2(6-1) experimental design. Controlled factors were treatment with ultrasonic radiation, full carbonation (addition of CO2 until the pH was stable for 2.5h), liquid-to-solid (L/S) ratio, pH, leaching temperature and time. Full carbonation, pH and the L/S ratio were the main factors controlling the mobility of DOC in the bottom ash. Approximately 60 weight-% of the total organic carbon (TOC) in the bottom ash was available for leaching in aqueous solutions. The L/S ratio and pH mainly controlled the mobilization of DOC from the APC residue. About 93 weight-% of TOC in the APC residue was, however, not mobilized at all, which might be due to a high content of elemental carbon. Using the European standard EN 13 137 for determination of total organic carbon (TOC) in MSWI residues is inappropriate. The results might be biased due to elemental carbon. It is recommended to develop a TOC method distinguishing between organic and elemental carbon.     

Joint influence of surfactants and humic matter on PAH solubility. Are mixed micelles formed?

Mobilization of polycyclic aromatic hydrocarbons (PAH) by surfactants, present at contaminated sites or deliberately introduced for remediation purposes, is inevitably associated with the influence of humic substances, which are ubiquitous in natural systems. Therefore, the solubilizing effects of anthropogenic and natural amphiphiles must be considered in their combined action since synergistic or antagonistic effects may be expected, for instance, as a consequence of mixed micellization.

In this paper, solubilization of ¹⁴C-labeled pyrene in single-component and mixed solutions of surfactants and humic acid (coal-derived) was investigated up to the micellar concentration range. At low concentrations, antagonistic effects were observed for systems with cationic as well as anionic surfactants. Solubility enhancements in the presence of humic acid were canceled on addition of a cationic surfactant (DTAB) since charge compensation at humic colloids entailed precipitation. Solubility was also found to be decreased in the presence of an anionic surfactant (SDS), which was attributed to a competitive effect in respect of pyrene–humic interaction. This explanation is based on octanol–water partitioning experiments with radiolabeled humic acid, yielding evidence of different interaction modes between humic colloids and cationic/anionic surfactants. At higher concentrations, the effects of humic acid and SDS were found to be additive. Thus, a formation of mixed micelles is very unlikely, which was confirmed by size exclusion chromatography of mixed systems. It can be concluded that remediation measures on the basis of micellar solubilization are not significantly affected by the presence of natural amphiphilic compounds.     

Artificial carbonation for controlling the mobility of critical elements in bottom ash

In municipal solid waste incineration (MSWI), bottom ash, generated at a stoker grate type incinerator, the critical elements were identified in terms of EU regulation. The stabilizing effect of moderate carbonation (pH 8.28 ± 0.03) on critical contaminants was studied through availability and diffusion leaching protocols. Data from the performed tests were evaluated with the goal of reusing MSWI bottom ash as secondary construction material. To investigate the mobilizing effect of CO₂, suspended MSWI bottom ash was severely carbonated (pH 6.40 ± 0.07). The effect of CO₂ and its interaction with other leaching factors, such as liquid/solid (L/S) ratio, leaching time, pH, ultrasound treatment, and leaching temperature, were examined using a reduced 2^6-1 experimental design. Contaminants identified as critical were Cr, Cu, Mo, Sb, Cl⁻, and SO₄ ²⁻. Although moderate carbonation decreased the release of Cr, Cu, Mo, and Sb from compacted bottom ash, the main disadvantage remains its inability to demobilize Cl⁻ and SO₄ ²⁻. The hypothesized mobilizing effect of severe carbonation was proven. The treatment enhanced the separation of critical components (α = 0.05) (except for Cl⁻), i.e., about fivefold for Sb and about twofold for Cr, Cu, and S. Nevertheless, the prospect is good that severe carbonation could constitute the deciding key parameter to facilitate the technical feasibility of a future washing process for MSWI bottom ash.     

Leaching and crop uptake of nitrogen from nitrogen-15-labeled green manures and ammonium nitrate

Green manures can be used as an N source for agricultural crops as a substitute for inorganic N fertilizers. The effects of using green manures on leaching and uptake of N by spring barley (Hordeum vulgare L.) were evaluated in a 2-yr lysimeter study. Ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) labeled with (15)N were applied in May of the first year at 160 kg total N ha(-1). Simultaneously, (15)NH(4)(15)NO(3) was applied at 80 kg N ha(-1) to additional lysimeters and others were left without N additions (control). During the second year, all lysimeters, except the control, received 80 kg N ha(-1) as unlabeled NH(4)NO(3). The cumulative, average loads of total N leached during the two years were: 37 (control), 62 (NH(4)NO(3)), 50 (ryegrass manure), and 73 (red clover manure) kg ha(-1). The differences among the treatments were not significant (P > 0.05), but the control had significantly smaller (P < 0.05) leaching loads than the treatments. About 24% of ryegrass- and red clover-derived N and 43% of NH(4)NO(3) were removed through spring barley grain and stover during the two growing seasons. Thus, the N use efficiency in barley was substantially larger when grown with inorganic N fertilizer than when grown with green manure. Viewed in combination with the tendency for larger N leaching loads under red clover manure, claims about water quality benefits of legume-based green manures should be evaluated with regard to the timing of N release and demand for N by the plant.