Zinc kinetics in the ant Myrmica rubra originating from a metal pollution gradient

Ants are efficient trace metal accumulators, but metal kinetics in ants has not been described. Workers of Myrmica rubra collected in seven meadows along a metal pollution gradient were exposed to dietary Zn (1000 mg kg⁻¹) for a 80 day uptake period followed by 30 days of clean food. Zn concentrations in the ants from all study sites were found to have been maintained on a stable level, indicating very efficient Zn regulation. No proof of adaptation in terms of enhanced elimination or restricted accumulation of Zn was found. Nevertheless, the results illustrate the general kinetics of Zn in M. rubra, irrespective of the differences between sites.     

Multivariate analysis of mineral constituents of edible Parasol Mushroom (Macrolepiota procera) and soils beneath fruiting bodies collected from Northern Poland

Caps and stipes of 141 fruiting bodies of Parasol Mushroom (Macrolepiota procera) and surface layer of soils collected from 11 spatially distant and background (pristine) areas in Northern Poland were analyzed for Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, and Zn by inductively coupled plasma optical emission spectroscopy and cold vapor atomic absorption spectroscopy. In terms of bioconcentration and bioexclusion concept, K, Ag, Cu, Rb, and P were highly bioconcentrated in caps, and their bioconcentration factor values varied for the 11 sites between 120 and 500—67–420, 70–220, 10–170, and 45–100, respectively. Cd, Zn, Mg, and Na showed bioconcentration factors (BCFs) between 3.3 and 36, 3.7–15, 0.92–6.3, and 1.4–44 while Al, Ba, Ca, Co, Cr, Mn, Ni, Pb, and Sr were excluded (BCF < 1). The Parasol Mushroom is a species harvested in the wild, and its caps are of unique taste and can contain a spectrum of essential and hazardous mineral compounds accumulated at elevated concentrations, even if collected at the background (pristine) areas. These elevated mineral concentrations of the caps are due to the efficient bioconcentration potential of the species (K, Ag, Cu, Rb, P, Cd, Zn, Mg, and Na) and abundance in the soil substrates (Al, Ca, Fe, Mn). The estimated intake rates of Cd, Hg, and Pb contained in Parasol Mushroom’s caps show a cause for concern associated with these metals resulting from the consumption of between 300- and 500-g caps daily, on a frequent basis in the mushrooming season.     

Monitoring of atrazine in milk using a rapid tube-based ELISA and validation with HPLC

Although atrazine has been banned in the European Union since 2007 it still persists in soil from where it can enter the food chain. Milk-producing animals accumulate atrazine from contaminated feed and water and since large quantities of milk and milk products are consumed its quality should be constantly monitored. The objective of this investigation was to develop a simple tube ELISA procedure suitable for use in non-specialised laboratories and in the field. A polyclonal antibody raised in sheep and the hapten-gelatine conjugate was immobilised onto polystyrene tubes. This enables the colour produced to be read on a basic spectrophotometer. Milk samples were collected from three farms in different regions of Poland and diluted before immunoassay was performed. Samples were extracted with hexane-acetone for HPLC analysis. The amount of fat in the milk samples interferes with the dose response so it essential that the standards are prepared in the same samples matrix. A good correlation between 1% and 2% was found between the two methods in the analysis of real samples. However the ELISA procedure was more sensitive that the HPLC method since atrazine was detected in some samples by the ELISA but was not confirmed by the HPLC method. The study demonstrated that the simple antigen-coated tube assay provides a cost effective and valuable screening test that can be easily modified for direct use as a screening tool in the field.     

Luminescence in the oxidation of isoproterenol by the superoxide anion radical in dimethyl sulfoxide

Chemiluminescence appearing during oxidation of isoproterenol using chemical system involving superoxide anion radical has been studied. Chemiluminescence and fluorescence spectra were measured. The chemiluminescence spectrum was measured with cut‐off filters and revealed bands with maximum at 440, 480, 550, 640 and 700 nm. The bands at 480, 640 and 700 nm were similar to those observed for singlet oxygen. The fluorescence spectrum exhibited maximum at 560 nm.

The inhibitory effect of several biologically important compounds known as O₂ ^?‐ HO^? and ¹O₂ scavengers on the light emission was studied.

The obtained results indicate that oxidation of isoproterenol by O₂ ^?‐ involves products in the electronically excited states. The data also seem to indicate the protective effect of isoproterenol on the deoxyribose degradation.     

Metabolic pathways of polychlorinated biphenyls degradation by Pseudomonas sp. 2

Polychlorinated biphenyls (PCBs) included with the commercial mixture Delor 103 were degraded by immobilized cells of aerobic bacterial strain Pseudomonas sp. 2. The ability of the strain to metabolise selected tri- and tetrachlorobiphenyls, and the site of primary attack of the biphenyl skeleton were investigated. It was observed that the amount of residual PCBs was 1-48% of the original PCBs after three weeks of incubation. Identified metabolites indicate that the used bacterial strain attacks the biphenyl skeleton at the 2,3- and 3,4-positions, and it is also able to dehalogenate PCBs. Metabolic pathways of degradation of individual congeners were proposed. Transformation of 2,4- and 2,5-dichlorobenzoic acids by Pseudomonas sp. 2 was also observed.     

Distribution of Diatoms in a Forested Stream Containing a Series of Interconnected Lakes

We explored the spatial variation in diatom communities withinthe Turkey Lakes Watershed (TLW). The TLW is a single watershed in an old growth sugar maple forest that contains an alternatingseries of stream and lake embayments. Near the outlet of each lake, we sampled pools and riffles to determine abundance and diversity of diatom communities along this hydrologic system. Diatom diversity, measured by Shannon-Weaver Index, richness andevenness, increased steadily downstream before eventually decreasing near the watershed outlet. Canonical CorrespondenceAnalysis indicated that diatom genera were correlated with streamchemistry. Upper reaches were the least productive, characterizedby lower pH (<7), higher N:P (113:1 to 124:1, dominated by complex forms of N), and high mean relative abundances of Eunotia spp., Tabellaria spp., and Pinnularia spp. Middle and lower reaches were more productive, characterized byhigher pH (>7), lower N:P (71:1 to 90:1, dominated by simple forms of N, e.g., nitrate-N), and high mean relative abundances of Cymbella spp. and Brachysira spp. Achnanthesminutissima (Kutz.) Hustedt, the most abundant species, and Navicula spp., Nitzschia spp., Gomphonema spp., and Frustrulia spp. were represented at all stream sites. Thisstudy revealed that within the TLW, a hydrologic system of the same stream order, the diatom community was influenced by a nutrient gradient, where the stream and its intervening lakes contributed to a shift from acidic, inorganic N-poor upper reaches to a circum-neutral, inorganic N-richer outlet. By imparting genera-specific stresses, stream flow (i.e. pools vs. riffles) further shaped the diatom community.     

The influence of temperature and hydration on the sorption properties of bentonite

The effects of exposure to synthetic groundwater at elevated temperature gradients on the sorption properties of bentonite were investigated using the Mock-Up-Cz experiment. This experiment simulated the vertical placement of a container of radioactive waste according to the Swedish KBS-3 system for a period of more than 3 years. The mineralogical composition, as well as its chemical and physico-chemical properties, including the uptake of (99)TcO(4)(-) and (134)Cs(+), was used to evaluate the chemical changes caused by the long-term exposure of bentonite buffer to thermal and hydration gradients. It was found that the bentonite material was predominantly stable. No more than 2% of the montmorillonite was transformed due to thermal and moisture gradients. It was concluded that the new-formed mineral phases have no significant influence on the ion exchange and sorption properties of bulk bentonite samples.     

Hyperaccumulating potential of Bidens pilosa L. for Cd and elucidation of its translocation behavior based on cell membrane permeability

Environmental Science and Pollution Research - Phytoremediation with the use of hyperaccumulating plant species to remove excess trace metals from contaminated soil and water is considered a...