Optimized yeast-based in vitro bioassay for determination of estrogenic and androgenic activity of hydroxylated / methoxylated metabolites of BDEs / CBs and related lipophilic organic pollutants

ABSTRACT

Persistent organic pollutants (POPs) are known to show endocrine disrupting (ED) activity, including interactions with hormone receptors. The aim of this work was to develop a bioassay applicable for evaluation of ED potency of highly lipophilic metabolites of POPs. To that end, a yeast-based bio-assay protocol was used. Estrogenic / androgenic activity of some native brominated biphenyl ethers (BDEs) / chlorinated biphenyls (CBs), and their hydroxylated / methoxylated metabolites was assessed. Since data (including potency compared to reference native hormones) obtained using different protocols vary, the possibility that yeast transforms POPs into some more potent compounds was first checked; it seems that no such transformation is important from the test applicability standpoint. The developed method was sensitive with EC50 values 6.5*10^?11 M and 4.5*10^?9 M calculated for E2 and DHT, respectively. Both CBs and BDEs show weak estrogenic activity negatively correlated with the degree of their halogenation, but their metabolites are significantly more potent xenohormones. 4-OH-2,2′,4′,6′-TeCB was the most potent estrogen receptor (ER) agonist among all tested compounds; its activity was only 1,000 times lower than that of native E2.     

EDTA and urease effects on Hg accumulation by Lepidium sativum

The phytoextraction process was conducted under laboratory conditions with the use of garden cress plants (Lepidium sativum). The experiment was carried out in a model soil, which was characterized before conducting the process. Inorganic forms of mercury (HgCl(2), HgSO(4), Hg(NO(3))(2)) were used for contamination of the soil. The phytoextraction process was conducted after EDTA application to the soil and after urease application. Also the influence of simultaneous addition of ethylenediaminetetraacetic acid (EDTA) and urease into the soil on phytoextraction process was measured. In all variants of phytoextraction process the total mercury concentrations in roots, stems and leaves of garden cress were determined. The result showed that garden cress accumulated mercury from soil. The overall maximum concentration of mercury in its compounds was found in roots of the plant. In all cases, before addition of urease and EDTA, the translocation process and distribution of mercury in the plant tissues were limited. The addition of urease caused an increase of enzyme activity in the soil and at the same time caused an increase of mercury concentration in plant tissues. Application of EDTA increased solubility of mercury and caused an increase of metal accumulation by plants. After simultaneous addition of EDTA and urease into the soil garden cress accumulated about 20% of total mercury concentration in the soil. Most of mercury compounds were accumulated in leaves and stems of the plants (46.0-56.9% of total mercury concentration in the plant tissues).     

Metallakkumulation in Moosen: Standörtliche und regionale Randbedingungen des Biomonitoring von Luftverunreinigungen

Goal and Scope

Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.

Main Features

Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.

Results

No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.

Discussion

For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.

Conclusions

The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.

Recommendations

The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.

Perspectives

Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude.     

Circadian Rhythm of Heart Rate,Urinary Cortisol Excretion,and Sleep in Civil Air Traffic Controllers

The examination of Air Traffic Controllers (ATCs) from the Warsaw Airport (Poland) included 24-hr ECG monitoring. The participants were 10 civil ATCs, 9 males and 1 woman. The study was carried out on a group of 19 ATCs during their duty periods, 14 of them working 12-hr shifts and 5 performing 24-hr duties. The participants collected urine every 4 hrs, and Cortisol concentration was determined. Further, the survey included the quality and duration of sleep, and subjective fatigue in the 62 participants.

In ATCs, shift work modifies natural rhythms of the circulatory system and decreases the ability for intensified mental work at night. In consequence ATCs experience frequent sleep disorders.     

A system dynamics model to facilitate public understanding of water management options in Las Vegas,Nevada

Water managers increasingly are faced with the challenge of building public or stakeholder support for resource management strategies. Building support requires raising stakeholder awareness of resource problems and understanding about the consequences of different policy options. One approach that can help managers communicate with stakeholders is system dynamics modeling. Used interactively in a public forum, a system dynamics model can be used to explain the resource system and illustrate the effects of strategies proposed by managers or suggested by forum participants. This article illustrates the process of building a strategic-level system dynamics model using the case of water management in Las Vegas, Nevada. The purpose of the model was to increase public understanding of the value of water conservation in Las Vegas. The effects of policies on water supply and demand in the system are not straightforward because of the structure of the system. Multiple feedback relationships lead to the somewhat counterintuitive result that reducing residential outdoor water use has a much greater effect on water demand than reducing indoor water use by the same amount. The model output shows this effect clearly. This paper describes the use of the model in research workshops and discusses the potential of this kind of interactive model to stimulate stakeholder interest in the structure of the system, engage participant interest more deeply, and build stakeholder understanding of the basis for management decisions.     

Effects of sulphur deposition on trace metal solubility in soils

Concentrations of Fe, Mn, Zn, Pb, Cu and Cd in soil solutions taken in the vicinity of a sulphur mine range from 354 to 9080 μM L⁻¹, and exceeded the concentrations measured in solutions from light acid arable soils. The content of each metal was a negative function of either the solution pH or of Ca concentration. Reclamation of S-contaminated soil by an application of 2000 tonnes of limestone per hectare did not significantly affect the solubility of trace metals, whereas equilibration of soil samples with CaCO₃ in the laboratory decreased solubility of metals, especially in the soil under moist conditions. Sulphur deposition may modify the natural cycling of metals in soils.     

Determination of Alphacypermethrin in the Air by Capillary Gas Chromatography

A new method for sampling and chemical analysis of alphacypermethrin in workplace air has been described. Air samples were taken using a glass tube filled with silica gel with chemically bounded octadecyl phase. Chromatographic determinations were conducted using an HP-5 capillary column (10 m x 0.53 mm) and an electron-capture detector. Alphacypermethrin recovery was 100.15%. The calculated detection limit for a 60-L air sample was 0.0001 mg/m3.     

The long term behaviour of CFBC ash-water systems

Circulating fluidized bed combustion (CFBC) ashes in contact with water, whether in liquid or vapour form, exhibit considerable chemical activity, which can continue for more than a year. From the point of view of the setting of CFBC ash-water mixtures and their behaviour, the formation of gypsum and of ettringite are important. The crystallisation of ettringite is associated with expansion of the set mass and absorption of water into the solids, but the ash-water system as a whole shrinks. The extent of ettringite formation is reduced if carbonation of free lime can take place. There is little carbonation if the set solids are covered by water but if contact with air is not restricted, the ettringite formed earlier slowly decomposes, its place being taken by calcite and gypsum. The fate of the aluminium from decomposed ettringite is uncertain; no new crystalline Al compounds are found. It appears that ultimately most analytical lime present can become carbonated. This is environmentally beneficial since it reduces chemical activity in the landfill, and reduces the amount of CO2 released due to limestone use. The main features of the behaviour of CFBC ash-water mixtures can be reproduced in model systems (CaO-Al2O3-CaSO4-H2O) but that of real ashes is complicated by the presence of silicates and possible interactions between silica and the strongly alkaline aqueous medium. Also, aluminates present in the ash are probably more active with respect to ettringite formation than pure aluminum hydroxide.     

Fate of PBDEs during food processing: Assessment of formation of mixed chlorinated/brominated diphenyl ethers and brominated dioxins/furans

The aim of this study was to evaluate effects of food processing on PBDE levels, in particular influence of heat treatment on degradation of PBDEs, including possible formation of chlorinated diphenyl ethers or brominated dioxins/furans as degradation products. It was shown that PBDEs heated in the presence of chlorine (from either organic or inorganic sources) formed mixed chlorinated/brominated diphenyl ethers. However, no PCDEs were formed in the presence of lipids. Lipid medium increased stability of PBDEs exposed to UV irradiation. Profile of congeners formed in result of the debromination reaction was significantly different than profiles observed by some other authors in aliphatic organic solvents. Grilling processes increased concentrations (calculated on the fresh product basis) of the studied compounds by 4–8/22–34% for electric/coal grill, respectively. Depending on the congener and on the applied heat treatment, PBDE mass in pork meat after grilling dropped by 26–53%. No detectable quantities of either brominated dioxins or furans were formed during thermal processing of food containing typical levels of PBDEs.