Experimental and theoretical studies on formation and degradation of chloro organic compounds

Studies on oxidation of tert-butyl ethers in the presence of chloride ions proved that acid medium favoured formation of chloro organic compounds. 1,2-Dichloro-2-methylpropane, 3-chloro-2-chloromethylpropene were identified among the reaction products. Presence of these compounds was identified both in the case when methyl-tert-butyl ether (MTBE) and ethyl-tert-butyl ether (ETBE) were subjected to reaction. Reaction products were analysed by gas chromatography method with application of -FID, -MS and -AED detectors. On the basis of experimental data, the path of tert-butyl ethers conversion to dichloro products was proposed. It was found that the identified chloro derivatives could be formed both by ionic and radical reactions. In order to confirm this thesis for the proposed scheme of reaction, the theoretical calculations of molecular simulation of the reaction paths were performed.     

Relationships and bioaccumulation of chemical elements in the Baikal seal (Phoca sibirica)

Concentrations of Al, Ba, Cd, Cu, Fe, Mn, Mo, Si, Sr, Zn, Ca, K, Mg, Na and P in the livers of Baikal seal, plankton, zoobenthos, and fish, constituting the food sources for the seals, were determined by ICP-MS and ICP-AES. The accumulation of elements in the liver of seals, affected by internal and external (environmental) factors, was assessed by multidimensional (ANOVA, FA) and correlation analyses. FA has enabled identification of abiotic and biotic factors responsible for the accumulation of elements in the livers of Baikal seals. Significant influence of sex and development stage of the seals analysed on hepatic concentrations of some elements was found. The observed differences in element concentrations between pups, males and females could be attributable to the reproductive cycle of this species. ANOVA showed differences in concentrations of Fe, Zn, Cu and Cd in seals from the three separate basins of the lake. BMFs suggest biomagnification of Fe and Zn in the fish-seal trophic link.     

Management of adverse effects of a public water supply well field on the aquatic habitat of a stratified drift stream in eastern Connecticut.

A study was conducted to determine the effect of water withdrawals from the University of Connecticut's (Storrs) water supply wells on the fisheries habitat of the Fenton River adjacent to the well field. The study was designed to investigate the relationships between in-stream flow and selected fish habitat in the section of the Fenton River situated in the main zone of influence of the pumping field. With the aid of historical data, new data collection, and mathematical simulation modeling, the relation between the magnitude and timing of groundwater withdrawals on the stage and flow of water in the stream was derived. Fish sampling and habitat modeling were used to assess the effects of human influence on certain reaches of the Fenton River. Among the various water management scenarios studied, several are presented that would optimize water withdrawals, while minimizing adverse effects on the stream flow and in-stream habitat.     

The relationship between agricultural intensification and biological control: experimental tests across Europe

Agricultural intensification can affect biodiversity and related ecosystem services such as biological control, but large-scale experimental evidence is missing. We examined aphid pest populations in cereal fields under experimentally reduced densities of (1) ground-dwelling predators (-G), (2) vegetation-dwelling predators and parasitoids (-V), (3) a combination of (1) and (2) (-G-V), compared with open-fields (control), in contrasting landscapes with low vs. high levels of agricultural intensification (AI), and in five European regions. Aphid populations were 28%, 97%, and 199% higher in -G, -V, and -G-V treatments, respectively, compared to the open fields, indicating synergistic effects of both natural-enemy groups. Enhanced parasitoid: host and predator: prey ratios were related to reduced aphid population density and population growth. The relative importance of parasitoids and vegetation-dwelling predators greatly differed among European regions, and agricultural intensification affected biological control and aphid density only in some regions. This shows a changing role of species group identity in diverse enemy communities and a need to consider region-specific landscape management.     

Tailoring mesoporosity of poly(furfuryl alcohol)-based activated carbons and their ability to adsorb organic compounds from water

In this work it was shown that polymers can be recycled into a promising adsorbent for organic dyes and phenols waste removal. For this, a series of activated carbons (ACs) were produced from mixture of ferrocene or titanium acetylacetonate with poly(furfuryl alcohol) (PFA) by steam activation. The introduction of ferrocene as Fe precursor was found to be an efficient catalyst in mesoporosity development during carbonization and subsequent steam activation at 850 °C, whereas the polymer based only and titanium-doped ACs are typically microporous. The porous structure parameters were determined from nitrogen adsorption isotherms measured at 77 K. Scanning electron microscopy was applied to monitor the metal distribution of metal-loaded char and the surface morphology of activated carbons. The adsorption capacity was found to be dependent mainly on pore size distribution. In the case of phenol adsorption, the adsorption was defined by volume of pore with size 0.8–1.4 nm; whereas, for Congo red best fit was observed for volume of pore with size 2–5 nm.

     

Using gas chromatography for indoor-air quality control in conservation and renovation studios.

Investigations were carried out in the Department of Conservation of Painting and Polychrome Sculpture and in the Screen Printing Studio of the Faculty of Art at Nicolaus Copernicus University. Concentration of the vapours of organic solvents was measured in 2 workshops: the Art Conservation Studio and the Screen Printing Studio. This study attempts to evaluate the work environment in both studios by analysing the concentration of vapour solvents over 5 to 7 years of measurements. Volatile solvents--aliphatic and aromatic hydrocarbons, alcohols, esters and ketones--were detected in investigated workplaces. These compounds have a wide range of applications in cleaning and removing old varnishes, lacquers and paints; inhalation is the main route of exposure. Vapour was collected using an active sampling method.     

Impact of environmental factors on the sampling rate of β-blockers and sulfonamides from water by a carbon nanotube-passive sampler

Passive techniques are a constantly evolving approach to the long-term monitoring of micropollutants, including pharmaceuticals, in the aquatic environment. This paper presents, for the first time, the calibration results of a new CNTs-PSDs (carbon nanotubes used as a sorbent in passive sampling devices) with an examination of the effect of donor phase salinity, water pH and the concentration of dissolved humic acids (DHAs), using both ultrapure and environmental waters. Sampling rates (R_s) were determined for the developed kinetic samplers. It has been observed that the impact of the examined environmental factors on the R_s values strictly depends on the type of the analytes. In the case of β-blockers, the only environmental parameter affecting their uptake rate was the salinity of water. A certain relationship was noted, namely the higher the salt concentration in water, the lower the R_s values of β-blockers. In the case of sulfonamides, water salinity, water pH 7–9 and DHAs concentration decreased the uptake rate of these compounds by CNTs-PSDs. The determined R_s values differed in particular when the values obtained from the experiments carried out using ultrapure water and environmental waters were compared. The general conclusion is that the calibration of novel CNTs-PSDs should be carried out under physicochemical conditions of the aquatic phase that are similar to the environmental matrix.     

Concentrations of toxic heavy metals and trace elements in raw milk of Simmental and Holstein-Friesian cows from organic farm

Concentrations of toxic heavy metals (cadmium (Cd), lead (Pb)) and major nutritional and trace elements (Ca, Mg, P, Cu, Fe, Mn, Se, Zn) were analyzed in the milk of Simmental (n?=?20) and Holstein-Friesian (n?=?20) cows from an organic farm. Elements were determined using inductively coupled plasma emission atomic spectrometry. The conducted research showed that the milk of Simmental cows was characterized by the more advantageous mineral composition and lower concentration of noxious heavy metals compared to the milk of Holstein-Friesian cows. In the milk of Simmental cows, significantly lower concentrations of Pb and Cd (P?<?0.001) and Cu (P?<?0.05) and significantly higher concentrations of Fe and Mg (P?<?0.05) as well as nonsignificantly higher concentrations of Ca, Mn, and Se were found. In the milk of both breeds, very low Cu concentrations were recorded. The higher-than-recommended concentration of Pb in milk was also found. In the milk of both breeds, the significant positive correlations between concentrations of the following elements were observed: Pb–Cd, Pb–Se, Cd–Se, Cd–Mn, Zn–Cu, Zn–P, Ca–P, Ca–Mg, and Mg–P. The correlations between other elements within each of the analyzed breeds separately were also found.     

Past and future trends in concentrations of sulphur and nitrogen compounds in the Arctic

Recent trends in nitrogen and sulphur compounds in air and precipitation from a range of Arctic monitoring stations are presented, with seasonal data from the late 70s to 2004 or 2005. Earlier findings of declining sulphur concentrations are confirmed for most stations, while the pattern is less clear for reduced and oxidized nitrogen. In fact there are positive trends for nitrogen compounds in air at several stations. Acidity is generally reduced at many stations while the precipitation amount is either increasing or stable. Variability of sulphate concentrations in air for the period 1991–2000 is reasonably well reproduced at most stations using an Eulerian, hemispherical model. Results for nitrogen compounds are weaker. Scenario studies show that even if large sulphur emission reductions take place in important source regions in South-East Asia in the coming decades, only small changes in Arctic deposition can be expected. This is because South-East Asian emissions have small influence north of the Arctic circle.