Occurrence of organophosphate flame retardants in farmland soils from Northern China: Primary source analysis and risk assessment.

Ninety-eight soil samples were collected from farmland soils from Beijing-Tianjin-Hebei core area, Northern China, where agricultural lands were subjected to contamination from intense urban and industrial activities. Twelve organophosphates flame retardants (OPFRs) were analyzed with total soil concentrations ranging from 0.543 μg/kg to 54.

Per- and Polyfluoroalkyl Substances (PFASs) in Indoor Air and Dust from Homes and Various Microenvironments in China: Implications for Human Exposure.

A newly developed solid-phase extraction cartridge composed of mixed sorbents was optimized for collection of both neutral and ionizable per- and polyfluoroalkyl substances (PFASs) in indoor air. Eighty-one indoor air samples and 29 indoor dust samples were collected from rooms of homes and hotels, textile shops, and cinemas in Tianjin, China. Fluorotelomer alcohols (FTOHs) were the predominant PFASs found in air (250-82 300 pg/m) and hotel dust (24.

Transfusion practice in anemic, non-bleeding patients: Cross-sectional survey of physicians working in general internal medicine teaching hospitals in Switzerland.

Background: Transfusion practice might significantly influence patient morbidity and mortality. Between European countries, transfusion practice of red blood cells (RBC) greatly differs. Only sparse data are available on transfusion practice of general internal medicine physicians in Switzerland.

Water quality criteria for total suspended solids (TSS) in urban wet-weather discharges.

Total suspended solids (TSS) from combined sewer overflows (CSOs) and stormwater discharges represent a crucial parameter for evaluating wet-weather pollution in urban areas. In fact, the increase of TSS in water during rain events can have ecotoxic effects on aquatic organisms. Furthermore, major potentially harmful substances such as heavy metals, PAHs and organic matter are adsorbed onto TSS and later settle on sediment.

Using decision analysis to determine optimal experimental design for monitoring sewer exfiltration with tracers.

The tracer methods developed to assess exfiltration from sewers in the European project APUSS (assessment of the performance of sewer systems) have a high degree of freedom with regard to the choice of tracer and the dosing strategy. These can lead to very different degrees of uncertainty in the measured exfiltration ratio. In this study, we demonstrate how to select an optimal experimental design using decision analysis, which accounts for this uncertainty and its associated costs.

Activated sludge modelling: past, present and future.

Model complexity in activated sludge modelling has increased over 30 years in parallel with the computational power of computers. Today, the complexity of biokinetics has reached a practical limit. Future advances may be in the direction of enhanced spacial resolution (CFD, single organisms) respectively, in repetitive computations (MC simulation, parameter identification).

Uncertainty, imprecision, and the precautionary principle in climate change assessment.

Statistical decision theory can provide useful support for climate change decisions made under conditions of uncertainty. However, the probability distributions used to calculate expected costs in decision theory are themselves subject to uncertainty, disagreement, or ambiguity in their specification. This imprecision can be described using sets of probability measures, from which upper and lower bounds on expectations can be calculated.

A novel beta-peptidyl aminopeptidase (BapA) from strain 3-2W4 cleaves peptide bonds of synthetic beta-tri- and beta-dipeptides.

A novel bacterial strain that was capable of growing on the beta-tripeptide H-betahVal-betahAla-betahLeu-OH as the sole carbon and nitrogen source was isolated from an enrichment culture. On the basis of physiological characterization, partial 16S rRNA sequencing, and fatty acid analysis, strain 3-2W4 was identified as a member of the family Sphingomonadaceae. Growth on the beta-tripeptide and the beta-dipeptide H-betahAla-betahLeu-OH was observed, and emerging metabolites were characterized.

Photoinduced oxidation of antimony(III) in the presence of humic acid.

Interactions of antimony with natural organic matter (NOM) are important for the fate of Sb in aquatic systems. The kinetics of the photosensitized oxidation of Sb(III) to Sb(V) in the presence of Suwannee River Humic Acid (SRHA) was investigated using UV-A and visible light (medium-pressure mercury lamp). At a concentration of 5 mg L(-1) dissolved organic carbon (DOC) the light-induced reaction was 9000 times faster (rate coefficient k(exp) = 7.

Chemical nitrite oxidation in acid solutions as a consequence of microbial ammonium oxidation.

In long-term experiments with membrane aerated biofilm reactors we observed complete nitrite oxidation in highly concentrated ammonium nitrite solutions with a contaminant pH decrease to values below 3. The maximum initial concentration for ammonium was 42 mM and for nitrite was 41 mM. We hypothesized that (1) acid-tolerant ammonium oxidizing bacteria were responsible for the pH decrease, and (2) chemical processes caused complete nitrite oxidation at low pH values.

Influence of metal speciation in natural freshwater on bioaccumulation of copper and zinc in periphyton: a microcosm study.

The free ion activity model (FIAM) has already been confirmed under laboratory conditions for many trace metals but has still to be validated under natural conditions where the presence of natural organic ligands influences metal speciation and bioavailability. The goal of this study was to test if the FIAM is followed under natural conditions by measuring copper and zinc speciation as well as metal accumulation in periphyton. Periphyton was exposed in microcosms to natural river water with different added concentrations of copper (25-258 nM) or zinc (18-501 nM) and additions of a synthetic ligand (NTA).

Systems analysis in environmental engineering: how far should we go?

Systems analysis is identified as a unifying topic of environmental engineering. Based on a questionnaire sent out to peers and based on the experience with an advanced systems analysis course the possible content and association of the content with bachelor and master's programs is discussed. At the bachelor's level it is concluded that an array of topics should be introduced more in an inductive way, going along with the discussion of examples.

Mechanisms and products of surface-mediated reductive dehalogenation of carbon tetrachloride by Fe(II) on goethite.

Natural attenuation processes of chlorinated solvents in soils and groundwaters are increasingly considered as options to manage contaminated sites. Under anoxic conditions, reactions with ferrous iron sorbed at iron(hyro)xides may dominate the overall transformation of carbon tetrachloride (CCl4) and other chlorinated aliphatic hydrocarbons. We investigated mechanisms and product formation of CCl4 reduction by Fe(II) sorbed to goethite, which may lead to completely dehalogenated products or to chloroform (CHCl3), a toxic product which is fairly persistent under anoxic conditions.

Quantification of oxygen fluxes in a long gravity sewer.

Quantification of the oxygen fluxes in the sewer system is at present the optimal methodology to obtain information about the influence of sewers on transformations and mass balances in the urban drainage system. However, the relative and absolute values of these fluxes are practically unknown. In this work, the oxygen fluxes were quantified experimentally in a full-scale aerobic main sewer.

Accumulation of copper and zinc in periphyton in response to dynamic variations of metal speciation in freshwater.

Although the free ion activity model (FIAM) has been well-established in laboratory studies, there remains the need for field data in order to validate the applicability of this model in natural systems. The objective of this study was to investigate the response of copper and zinc accumulation in periphyton to short-term variations in metal concentration and speciation in freshwater. During heavy rain events, dissolved Cu in the Furtbach stream increased from 40 to 118 nM, while dissolved Zn increased from 45 to 147 nM due to the release of metals from contaminated sediments.

High temporal resolution monitoring of inorganic nitrogen load in drainage waters.

Nitrate (NO3-), ammonium (NH4+) and pH were monitored with a novel flow cell equipped with ion-selective electrodes (ISEs) in a drainage pipe during one year. The high temporal resolution of the measurements (six measurements per hour) allowed the detection of diurnal oscillations in pH, NO3- and NH4+ concentrations, the relation of variations in concentrations to discharge rates changing during rain events, understanding of the processes resulting in such variations and tracing of unpredictable manure spills. Annual loads estimated from random samples collected every second day tended to underestimate the "true" loads calculated from quasi-continuous electrode measurements by 550% for NH4+ and 22% for NO3-.

Influence of organic carbon decomposition on calcite dissolution in surficial sediments of a freshwater lake.

A multi-sensor approach was used to determine high-resolution porewater gradients of Ca(2+), CO(3)(2-), H(+) and O(2) in sediment cores along a depth transect from eutrophic Lake Sempach (Switzerland). We quantified the reproducibility of measurements and analyzed concentration profiles with a one-dimensional diffusion-reaction model to quantify benthic fluxes. Calculation of oxic respiration in the sediment showed that almost all settled organic carbon was degraded with O(2) at shallow depths while only 28% was decomposed aerobically at the deepest location.

Solid-state and multidimensional solution-state NMR of solid phase extracted and ultrafiltered riverine dissolved organic matter.

In this study we used multidimensional solution-state NMR to elucidate the differences in the chemical composition of solid phase extracted and ultrafiltered DOM isolates. DOM was isolated from water sampled from an oligotrophic river, the River Tagliamento (Italy). The recovery of total DOM was up to 42% with both isolation techniques.

Ground water pollution by roof runoff infiltration evidenced with multi-tracer experiments.

The infiltration of urban roof runoff into well permeable subsurface material may have adverse effects on the ground water quality and endanger drinking water resources. Precipitation water from three different roofs of an industrial complex was channelled to a pit and infiltrated into a perialpine glaciofluvial gravel-and-sand aquifer. A shaft was constructed at the bottom of the pit and equipped with an array of TDR probes, lysimeters and suction cups that allowed measuring and sampling soil water at different depths.

P, As, Sb, Mo, and other elements in sedimentary Fe/Mn layers of Lake Baikal.

Distinct layers with accumulated iron and manganese oxyhydroxides are found in the recent sediments of Lake Baikal (Siberia). In the South and Central Basins, these concretions accumulate close to the sediment-water interface. In northern Lake Baikal and the area of Academician Ridge, however, massive Fe/Mn crusts are formed within several thousand years at redox fronts 10 to 15 cm below the sediment surface.

Influence of biodegradation processes on the duration of CaCO3 as a pH buffer in municipal solid waste incinerator bottom ash.

The long-term leachability of heavy metals from municipal solid waste incinerator (MSWI) bottom ash is of concern because of its potential use as a secondary construction material. Calcite is the most important long-term buffer in MSWI bottom ash as it buffers solutions during percolation and is an important factor in the control of heavy-metal mobility. It has been argued that biodegradation of residual organic material in the MSWI is a significant source of acidity.

Sorption mechanisms of zinc to calcium silicate hydrate: sorption and microscopic investigations.

Knowledge of the binding mechanisms of heavy metals to cement minerals is essential for the prediction of the long-term leachability of secondary building materials and cement-stabilized wastes containing heavy metals. In this study, the sorption of Zn(II) to calcium silicate hydrate (C-S-H(I)) in pre-equilibrated aqueous suspensions has been investigated as a function of time (up to 87 d), pH (11.7, 12.

Noble gas and major element constraints on the water dynamics in an alpine floodplain.

The hydrogeological system of an ecologically sensitive alpine floodplain in the Valle di Blenio, Switzerland, was investigated using hydrochemical and 3H-3He dating methods. Water samples from six wells and from different surface locations were analyzed. The analysis of the concentrations of major ions in conjunction with age determination by the 3H-3He-method allowed the main hydrological properties of the system to be consistently characterized.

Fish cell lines as versatile tools in ecotoxicology: assessment of cytotoxicity, cytochrome P4501A induction potential and estrogenic activity of chemicals and environmental samples.

In vitro systems such as primary cells and cell lines are of growing importance in ecotoxicology. Cells from different tissues and species of fish are used for the assessment of toxic action of chemicals and evaluation of environmental samples. For organotins and substituted phenols, we have found that the in vitro cytotoxicity is positively correlated with the acute toxicity in vivo, and therefore cytotoxicity assays may serve as an alternative for acute fish toxicity testing.