Non-selective signal loss in the 13C CPMAS NMR spectra of soil organic matter. Investigations of particle size fractions

In 13C cross-polarisation magic angle spinning (CPMAS) spectra of soil samples, the paramagnetic soil constituents partially discriminate against the signal intensity of the 13C atoms. The aim of the present study was to check to what extent this signal depression depends on the paramagnetic ion content and if it is selective for a certain kind of carbon species. The spectra of a variety of particle size fractions of five quite different soils were recorded. A procedure was developed to compare quantitatively the relative carbon content of the different spectra. It was found that iron ions differ in their efficiency to discriminate against the carbon signals. Nevertheless a strong linear correlation between the detectability of carbon and cube root(wt.%Fe) was observed for both the total signal and the signal of the different carbon species as well. This underlines that iron ions mainly influence the depression of the 13C signal in soil spectra. Furthermore we found, that for C: Fe ratios of 1.5 to 20 non-selective signal losses dominate. Despite a high percentage of non-detectable carbon (up to 90%), the 13C CPMAS spectra of our soil samples correctly reflect the relative composition of soil organic matter.     

Structural elucidation of main ozonation products of the artificial sweeteners cyclamate and acesulfame

Purpose  

The two artificial sweeteners cyclamate (CYC) and acesulfame (ACE) have been detected in wastewater and drinking water treatment plants. As in both facilities ozonation might be applied, it is important to find out if undesired oxidation products (OPs) are formed.     

Annoyance due to aircraft noise has increased over the years—Results of the HYENA study

In the HYENA study (HYpertension and Exposure to Noise near Airports) noise annoyances due to aircraft and road traffic noise were assessed in subjects that lived in the vicinity of 6 major European airports using the 11-point ICBEN scale (International Commission on Biological Effects of Noise). A distinction was made between the annoyance during the day and during the night. L_den and L_night were considered as indicators of noise exposure. Pooled data analyses showed clear exposure–response relationships between the noise level and the noise annoyance for both exposures. The exposure–response curves for road noise were congruent with the EU standard curves used for predicting the number of highly noise annoyed subjects in European communities. Annoyance ratings due to aircraft noise, however, were higher than predicted by the EU standard curves. The data supports other findings suggesting that the people's attitude towards aircraft noise has changed over the years, and that the EU standard curve for aircraft noise should be modified.     

Novelty Detection – Recognition and Evaluation of Exceptional Water Reflectance Spectra

The aim of environmental surveillance is to monitor known phenomena as well as to detect exceptional situations. Synoptic monitoring of large areas in coastal waters can be performed by remote sensing using multispectral sensors onboard satellites. Many methods are in use which enable the detection and quantification of ‘standard algae’ or specific algae blooms using their known spectral response. The present study focusses on the detection of spectra outside the known range and which are referred to as exceptional spectra. In a first step observations from a one-year period were used to establish the parameterisation of what is defined as ‘normal.’ In a second step observations from a different period were used to test the novelty detection application, i.e. to look for features not occurring in the first period.      

In vitro Screening von Pflanzenschutzmittel-Wirkstoffen auf östrogene Aktivität

Over the last years, the obviously increasing, hormone-dependent impairments observed in humans and animals, as well as the increased occurrence of hormone-dependent types of cancer, are sometimes associated with environmental chemicals which are suspected to imitate or block the effects of natural hormones. For a variety of environmental chemicals an endocrine efficacy could already be demonstrated. Little is known, however, about a possible hormonal activity of plant protection agents which are at present certificated in the Federal Republic of Germany. The aim of the present study was the in vitro testing of at least 57 active ingredients of pesticides and growth regulators certificated in the Federal Republic of Germany, for their possible estrogenic activity. The E-Screen-Assay based on the human breast cancer cell line MCF-7 was used as the suitable test system. For at least 8 of the tested substances, an receptor-mediated estrogenic activity could be shown in vitro. With the exception of one substance, 7 active ingredients displayed a very weak affinity for the human estrogen receptor. Their ability to displace 17β-estradiol from the receptor was low. Only the herbicide Pendimethalin is to be classified as a full estrogen receptor agonist; it is able to displace 17β-estradiol almost completely from the receptor. Howeverm the estrogenic potency of Pendimethalin, in comparison to 17β-estradiol, was seen to be as small as the estrogenic potency of the other 7 substances tested positively in the E-Screen-Assay. Among this 7 substances, two could not be classified as estrogenically active anymore, because their affinity to the human estrogen receptor was too weak. The relevance of the available results for livng organisms should be clarified in further in vivo investigations.     

Cardiac defects in chromosomally abnormal human embryos of 10–14 weeks' gestation

Cardiac defects were studied in five chromosomally abnormal embryos of 10–14 weeks' gestation by free-hand microdissection of hearts measuring 2·5–6 mm in diameter. The type of cardiac malformation alone or in association with other anomalies helped to confirm the chromosome diagnosis established prenatally by chorionic villus sampling or after spontaneous abortion. It was suggestive of a chromosomal disorder in one case in which cytogenetic investigation had failed.     

Prenatal diagnosis and perinatal management of a fetal ovarian cyst

A case of a prenatally diagnosed fetal ovarian cyst is presented. The pregnancy was complicated only by polyhydramnios, and some degree of fetal bowel obstruction could be recognized on sonogram. The newborn was delivered vaginally in the 39th week of pregnancy, and the cyst was removed by laparotomy on the day of the delivery. The etiology of this rare fetal condition is unknown.     

Evaluation of the respicon as a personal inhalable sampler in industrial environments

The Respicon has been introduced as a sampler for health related measurements of airborne contaminants at workplaces. The instrument is aimed at simultaneous collection of three health related aerosol fractions: (a) the coarser inhalable fraction, defining the aerosol fraction that may enter the nose and mouth during breathing; (b) the intermediate thoracic fraction, defining the fraction that may penetrate beyond the larynx and so reach the lung; and (c) the finer respirable fraction, defining the fraction that may penetrate to gas exchange region of the lung. The instrument has a number of features attractive to occupational hygienists: in addition to providing the three aerosol fractions simultaneously, it is light and compact enough to be used as a personal sampler. yet can be a tripod mounted for area sampling, it can provide samples not only for gravimetric analysis but also microscopic and chemical analyses; and it is also available in a photometric direct-reading version. The instrument has previously been evaluated as an area sampler and, in this mode of operation, has shown reasonable accuracy in collecting respirable, thoracic and inhalable particles, the latter up to particle diameters of ca. 80 microm. Except for some scattered unpublished data there exist no systematic investigations in the Respicon's performance when used as a personal sampler in the industrial environment. In this paper, we will report on a study of side by side comparison of the Respicon with the IOM inhalable sampler, regarded as a reference instrument for the inhalable fraction. The main study was performed at six different workplaces in a nickel refinery. Statistical analysis of the gravimetrically-determined concentration data reveals consistently lower aerosol exposure values for the Respicon as compared to the IOM sampler. The data for the nickel workplaces are compared with findings from other studies. The results are interpreted in the light of the overall results and the possibility of introducing a correction factor is discussed.     

Scalar transport from point sources in the flow around a finite-height cylinder

This paper presents a large eddy simulation of mass transfer in the flow around a surface-mounted finite-height circular cylinder. The study was carried out for a cylinder with height-to-diameter ratio of 2.5 and a Reynolds number based on the cylinder diameter of 44000. The approach flow boundary layer had a thickness of about 10% of the cylinder height. A tracer was released at various levels upstream of the cylinder. The effect of the release position in the subsequent spreading and dilution of the plumes is analyzed. It is found that a tracer released at the top or at mid-height is entrained into the recirculation zone behind the cylinder, and therefore presents similar plume evolution in the far wake in both cases. If the tracer is released at around three-quarters of the height of the cylinder, it is not significantly entrained by the main recirculation region, leading to smaller rates of spreading of the plume. Finally, if the tracer is released near the floor, the plume is entrained by the horseshoe vortex that wraps around the cylinder, leading to a large lateral spreading of the plume, remaining always near the floor.     

Polycyclic aromatic hydrocarbons and trace metal contamination of coastal sediment and biota from Togo

The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from <4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combustion activities. The sediments were also analyzed for major elements and a total of 15 trace metals, which were found in elevated concentrations. The calculated enrichment factor (EF) values relative to the Earth's crust show that the contamination is extremely severe for Cd (EF = 191), severe for Cr (EF = 18) and U (EF = 17.8), moderately severe for Zr (EF = 8.8), for Ni (EF = 6.8), Sr (EF = 5.9) and Ba (EF = 5.4), and moderate for V (EF = 3.6) and Zn (EF = 3.4). Sediments sampled in areas affected by the dumping of phosphorite mine tailings showed particularly high concentrations of trace metals. Overall, concentrations of both PAHs and trace metals in sediment tend to increase from the coastline to the open sea (2 km offshore). This is attributable to the increasingly finer texture of coastal sediment found offshore, which has a terrigenous origin and appears loaded with various contaminants through adsorption processes. Such high loads of trace metals were also found in the biota (fish and mussels). The ratio of measured trace metal concentrations in biota to threshold limits set by the World Health Organization herein defined as relative health factor (RHF) was high. Average RHF values in fish were highest for Se (470), As (250), Ag (97), Ni (78), Mn (63), Fe (53), Pb (36), Cd (10), and Cr (7) while lowest for Cu (0.08) and Zn (0.03). Cd and Al did not bioaccumulate in the analyzed fish species. In mussels, the RHF values were highest for Fe (9,108), As (295), Pb (276), Se (273), Mn (186), Ni (71), Ag (70), Cd (14), and Cu (4).