Jürgen W. Einax

Chemometrics in environmental analysis

Part 1 Chemometric methods: measurements and basic statistics experimental design and analysis of variances sampling and sampling design multivariate data analysis graphical methods data preprocessing cluster analysis factorial methods multivariate classification multivariate modelling time series analysis. Part 2 Case studies: atmosphere hydrosphere pedosphere related topics. (Part contents).

Occurrence and fate of organophosphorus flame retardants and plasticizers in coastal and marine surface waters.

This comprehensive study focused on the spatial and seasonal variations of organophosphorus flame retardants and plasticizers (OPs) in surface water from the estuary of the River Elbe and the German Bight (North Sea). 100 surface water samples were extracted by solid phase extraction (SPE) and analyzed by gas chromatography-mass spectrometry (GC-MS) with regard to 16 different OPs. The dominating substance was found to be tris(1-chloro-2-propyl) phosphate (TCPP) (Elbe: 40-250 ng L(-1), German Bight: 3-28 ng L(-1)). Furthermore, triethyl phosphate (TEP), tri-iso-butyl phosphate (TiBP), tris(2-butoxyethyl) phosphate (TBEP), and triphenylphosphine oxide (TPPO) were detected in concentrations up to 180 ng L(-1). Seasonal trends were detected for the longitudinal profile of the Elbe estuary. Besides the dilution of river water with North Sea water toward the mouth, leading to decreasing concentrations at the four sampling cruises (March, May, August, and October, 2010), an additional depletion of non-halogenated OPs was observed in summer which is supposed to be due to biodegradation or photodegradation. In addition, a comparison of all important tributaries of the German Bight (Elbe, Ems, and Weser) as well as the indirect tributaries Meuse, Rhine, and Scheldt was done by multivariate statistical methods. It could be shown that the contribution of non-halogenated alkylated OPs in the Rhine was higher than in all other tributaries. The riverine input of OPs into the North Sea via the investigated tributaries was estimated to be about 50 tyr(-1).

Distribution of mercury over the Atlantic Ocean in 1996 and 1999–2001

Abstract A series of measurements of total gaseous mercury (TGM) made over the Atlantic Ocean in 1977–1980, 1990, and 1994 has been continued by measurements made on board the research vessel (RV) Polarstern during three cruises: from Bremerhaven to Punta Quilla (October–November 1996), Bremerhaven–Cape Town–Antarctica–Cape Town (December 1999–March 2000), and Antarctica–Punta Arenas (February 2001). The data from these cruises are presented and compared with the data from previous cruises. In both hemispheres the average and median TGM concentrations in 1996 and 2000 were comparable to those measured in 1977–1980 but substantially lower than those observed in 1990. TGM measurements on board ships proved to provide a valuable complementary information to measurements by a ground based monitoring network since they show a large-scale distribution and can provide information about sources of mercury and its long-range transport in areas not covered by the present monitoring network.

Geostatistical and multivariate statistical methods for the assessment of polluted soils—merits and limitations

Abstract The complexity and the large variance of environmental data sets limit the use of common statistical methods for the assessment of the state of pollution. Therefore, the application of geostatistical and multivariate statistical methods is recommended. In principle, both types of statistics are able to detect spatial or temporal structures in data sets. The merits and limitations of these statistical methods shall be demonstrated for the investigation of three very different examples of soil pollution. The first case study is characterized by a distinct spatial structure and a relatively large number of samples. Both geostatistical and multivariate statistical methods are well suited for the characterization of the state of pollution. The second example is typical for a case study under practical and economic limitations. In this case it is possible to describe the polluted area semiquantitatively by means of multivariate statistical methods. The third data set is characterized by a relatively diffuse distribution of the contaminants in an old uranium mining waste dump. Methods of homogeneity testing can be used as an alternative to geostatistical and multivariate statistical methods.

Mitochondrial hormesis links low-dose arsenite exposure to lifespan extension.

Arsenite is one of the most toxic chemical substances known and is assumed to exert detrimental effects on viability even at lowest concentrations. By contrast and unlike higher concentrations, we here find that exposure to low‐dose arsenite promotes growth of cultured mammalian cells. In the nematode C. elegans, low‐dose arsenite promotes resistance against thermal and chemical stressors and extends lifespan of this metazoan, whereas higher concentrations reduce longevity. While arsenite causes a transient increase in reactive oxygen species (ROS) levels in C. elegans, co‐exposure to ROS scavengers prevents the lifespan‐extending capabilities of arsenite, indicating that transiently increased ROS levels act as transducers of arsenite effects on lifespan, a process known as mitohormesis. This requires two transcription factors, namely DAF‐16 and SKN‐1, which employ the metallothionein MTL‐2 as well as the mitochondrial transporter TIN‐9.1 to extend lifespan. Taken together, low‐dose arsenite extends lifespan, providing evidence for nonlinear dose‐response characteristics of toxin‐mediated stress resistance and longevity in a multicellular organism.

Hierarchical clustering extended with visual complements of environmental data set

Hierarchical clustering techniques complemented with visual display of data sets allow direct interpretation of the clustering results in terms of original variables. The proposed method of data ordering and display is simple, informative and fulfils fundamental objectives of the data visualisation techniques. In our study, it is applied for exploratory analysis of an environmental data set.

A fast and accurate method for the determination of total and soluble fluorine in toothpaste using high-resolution graphite furnace molecular absorption spectrometry and its comparison with established techniques

A fast and reliable method has been developed for the determination of total and soluble fluorine in toothpaste, important quality control parameters in dentifrices. The method is based on the molecular absorption of gallium mono-fluoride, GaF, using a commercially available high-resolution continuum source atomic absorption spectrometer. Transversely heated platform tubes with zirconium as permanent chemical modifier were used throughout. Before each sample injection, a palladium and zirconium modifier solution and a gallium reagent were deposited onto the graphite platform and thermally pretreated to transform them into their active forms. The samples were only diluted and introduced directly into the graphite tube together with additional gallium reagent. Under these conditions the fluoride was stable up to a pyrolysis temperature of 550 °C, and the optimum vaporization (molecule formation) temperature was 1550 °C. The GaF molecular absorption was measured at 211.248 nm, and the limits of detection and quantification were 5.2 pg and 17 pg, respectively, corresponding to a limit of quantification of about 30 μg g(-1) (ppm) F in the original toothpaste. The proposed method was used for the determination of total and soluble fluorine content in toothpaste samples from different manufactures. The samples contained different ionic fluoride species and sodium monofluorophosphate (MFP) with covalently bonded fluorine. The results for total fluorine were compared with those obtained with a modified conventional headspace gas chromatographic procedure. Accuracy and precision of the two procedures were comparable, but the proposed procedure was much less labor-intensive, and about five times faster than the latter one.

Challenges in Analytical Quality Assurance

Challenges in analytical quality assurance , Challenges in analytical quality assurance , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

Geostatistical investigations of polluted soils

Soil is one of the most endangered environmental compartments. Heavy metals are an important group of anthropogenic pollution sources. The high environmental variability of the metal contents of soil strongly limits the objective assessment of the pollution state. Geostatistical methods are an useful tool for the investigation of the spatial structure of pollutants and the objective description of the degree and the area of pollution. To demonstrate the applicability and the efficiency, semivariogram analysis and the kriging method have been applied to the investigation of the heavy metal pollution of soil in the surroundings of a large metallurgical plant. The character of the spatial distribution and the polluted territory can be assessed by application of these methods. It is possible to determine the minimum number of samples required for a representative description of the investigated area.

Mercury contamination in the northern Pantanal region Mato Grosso, Brazil☆

Abstract In gold mining areas around the world, mercury is used to separate gold by amalgamation. This often causes mercury contamination. Such a situation near the goldmines in the Pocone area, Mato Grosso, Brazil was investigated. Concentrations of mercury were determined in water, sediment and air. The results obtained in water showed elevated mercury concentrations of between 18 and 160 ng/l (filtered) compared to 25 ± 0.9 ng/l in a reference site. In sediments, total mercury concentrations were in the range from 23 to 198 ng/g (dw). Results of speciation analyses in water and sediment samples from two small rivers showed that only 10 to 50% of the mercury is easily reducible. At the beginning of the rainy season, volatile mercury concentrations of up to 8 ng/l resulted from leaching the tailings by the rain. In the ambient air near the gold mine region, concentrations of up to 6 ng/m 3 mercury were detected. Two meters above contaminated tailings, the values found were ten times higher. These results provide first information on transformations of mercury species and their pathways under tropical conditions.