Monitoring of persistent organic pollutants in Africa. Part 1: passive air sampling across the continent in 2008.

A 6-month air sampling survey was conducted at 26 sites across the African continent with the aim to establish baseline information on contamination of ambient air with persistent organic pollutants (POPs) as a reference for future monitoring programs in the region. Sampling sites included continental, rural and urban backgrounds, agricultural and industrial sites as well as waste and obsolete pesticide dumps. Concentrations of polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls and organochlorine pesticides were low at most of the rural background sites, but they raise some concern in big cities. The large temporal variability in the pesticide concentrations suggested seasonal application of gamma-HCHs and endosulfans; levels of p,p'-DDT were often much higher than those of p,p'-DDE and indicated recent application of DDT.

Monitoring of persistent organic pollutants in Africa. Part 2: design of a network to monitor the continental and intercontinental background.

A network for the study of long-term trends of the continental background in Africa and the intercontinental background of persistent organic pollutants as resulting from long-range transport of contaminants from European, South Asian, and other potential source regions, as well as by watching supposedly pristine regions, i.e. the Southern Ocean and Antarctica is designed. The results of a pilot phase sampling programme in 2008 and meteorological and climatological information from the period 1961-2007 was used to apply objective criteria for the selection of stations for the monitoring network: out the original 26 stations six have been rejected because of suggested strong local sources of POPs and three others because of local meteorological effects, which may prevent part of the time long-range transported air to reach the sampling site. Representativeness of the meteorological patterns during the pilot phase with respect to climatology was assessed by comparison of the more local airflow situation as given by climatological vs. observed wind roses and by comparison of backward trajectories with the climatological wind (NCEP/NCAR re-analyses). With minor exceptions advection to nine inspected stations was typical for present-day climate during the pilot phase, 2008. Six to nine stations would cover satisfyingly large and densely populated regions of North-eastern, West and East Africa and its neighbouring seas, the Mediterranean, Northern and Equatorial Atlantic Ocean, the Western Indian Ocean and the Southern Ocean. Among the more densely populated areas Southern Cameroon, parts of the Abessinian plateau and most of the Great Lakes area would not be covered. The potential of the network is not hampered by on-going long-term changes of the advection to the selected stations, as these do hardly affect the coverage of target areas.

A combined approach to the evaluation of organic air pollution - a case study of urban air in Sarajevo and Tuzla(Bosnia and Herzegovina).

Organic pollution is a complex mixture where besides usually discussed polycyclic aromatic hydrocarbons (PAHs) a lot of other toxic or potentially toxic compounds occur. In this case, the organic air pollution in two important industrial cities, Sarajevo and Tuzla, in Bosnia and Herzegovina (part of former Yugoslavia) was assessed with the emphasis placed on genotoxic risks using both chemical (PAHs analyses) and biological approaches (genotoxicity testing with a screening bacterial genotoxicity test - SOS chromotest). The study was performed as a part of the APOPSBAL project (ICA2-CT2002-10007). So far there has not been any information either about the PAHs pollution or the genotoxic activity of the organic air pollution for the localities under the study. Therefore, the presented information is considered absolutely unique. Both used approaches made possible to identify the localities with the highest pollution level and genotoxic risks in both cities. Generally, higher levels of both parameters were determined in Tuzla, which is much more industrialized than Sarajevo, and especially at localities close to city centers and affected by traffic emissions, but also at localities polluted by emissions from industry and household heating. Even if benzo(a)pyrene concentrations exceeded the maximum permitted levels for this pollutant at some localities in Tuzla, the PAHs concentrations were fully comparable with the levels determined in other industrial European cities. Significant genotoxicity of the organic extracts was detected for almost all of the urban localities in the test both without (-S9; direct genotoxicity) and with the addition of metabolic activation (+S9; indirect genotoxicity). The observed direct genotoxic activities were discussed in relation to a potential presence of PAHs derivatives in the air. The indirect genotoxic activities were apparently higher at the localities with higher contents of carcinogenic PAHs. The significant relationship between the determined genotoxic activities and the PAHs pollution was also confirmed by a regression analysis. However, the correlations were not absolute because the observed genotoxic activity was also dependent on the presence of other organic pollutants than the PAHs. It concerns predominantly direct genotoxicity which is not related with the PAHs, but with their nitro-, oxi-, and hydroxy-derivatives and also other unknown polar organic pollutants. However, the concentrations of the direct genotoxins apparently correlated with the PAHs contents in the air. The study showed that screening genotoxicity tests, such as the SOS chromotest, could be effectively used for the identification of localities with increased genotoxic risks. In comparison with the health risk assessment which is usually based on the chemical analyses of only a small part of the pollution mixture, the bioassays enable us to evaluate the risks of all the mixture. The localities with the highest detected human health risks according to the screening bioassays may then be analyzed in detail with specific chemical methods to identify their causes.

Evaluation of genotoxic and non-genotoxic effects of organic air pollution using in vitro bioassays.

In this study, organic extracts of total suspended particles (TSP) and the particulate matter (PM) with the size below 2.5 microm (PM(2.5)) combined with organic extracts of the gas phase (GP) collected at two urban and two background localities were analyzed with a bacterial genotoxicity test, SOS chromotest, and an in vitro test for the dioxin toxicity determination, using a modified cell-line of rat hepatoma H4IIE.luc. In addition, the samples of TSP and GP were analyzed for PAHs contents. The PAHs concentrations and both of the toxic activities at the urban localities were much higher than ones at the background localities. Predominantly, traffic was a source of the urban air pollution there which was also confirmed by the evaluation of portions of certain PAHs (BaP/BPE, PYR/BaP) at the localities. On the other hand, the background localities were apparently affected by a long-distance transport of the pollutants from urban and industrial centers. The results of the bioassays indicated potential health risks for the population exposed to the organic air pollutants, especially at the urban localities. Based on the collected samples, distribution of the organic pollutants with the toxic effects in the air was evaluated. The significant portion of the direct genotoxins was bound to the particles larger than 2.5 microm. On the contrary, the indirect genotoxins were bound predominantly to the particles with the size below 2.5 microm. However, in the urban air they may be also bound to the larger particles, as well. While the direct genotoxicity may be related with the presence of PAH-derivatives as well as some polar organic pollutants, the indirect genotoxicity is related with the detected carcinogenic PAHs. But besides the above specified pollutants it is also necessary to consider the presence of other toxic components of the complex organic air pollution mixture that may also show potential health risks. This study demonstrates application of the combination of the screening bioassays for the evaluation of organic air pollution and identification of its health risks.

AhR-mediated and antiestrogenic activity of humic substances.

Humic substances (HS) were for decades regarded as inert in the ecosystems with respect to their possible toxicity. However, HS have been recently shown to elicit various adverse effects generally attributed to xenobiotics. In our study, we used MVLN and H4IIE-luc cell lines stably transfected with luciferase gene under control of estrogen receptor (ER) and Ah receptor (AhR; receptor connected with so-called dioxin-like toxicity) for assessment of anti/estrogenic and AhR-mediated effects of 12 commercially available humic substances. Out of those, five humic acids were shown to induce AhR-mediated activity with relative potencies related to TCDD 2.6 x 10(-8)-7.4 x 10(-8). Organic extracts of HS solutions also elicited high activities what means that lipophilic molecules are responsible for a great part of effect. However, relatively high activity remaining in extracted solution suggests also presence of polar AhR-agonists. Contribution of persistent organic compounds to the observed effects was ruled out by H(2)SO(4) treatment. Eight out of twelve HS elicited significant antiestrogenic effects with IC(50) ranging from 40 to 164 mg l(-1). The possible explanations of the antiestrogenic effect include sorption of 17-beta-estradiol (E2) on HS, changes in membrane permeability for E2 or another specific mechanism.

Web portal for management of bioindication methods and ecotoxicological tests in ecological risk assessment.

The objective of this article is to inform about efforts to design and implement a data model that can parametrically describe and store information about a wide range of ecotoxicological tests and bioindication methods used in Ecological Risk Assessment (EcoRA). At the same time it describes comprehensive web-based portal built on this model that can be used to quickly find relevant biological assays (ecotoxicological biotests) for given situation and therefore support the decision-making process in EcoRA. The model structure, features of the corresponding website and its current content is described in detail and proposed development and possible collaboration is outlined. The portal (DATEST) is located at http://projects.cba.muni.cz/datest. The aim of this work is to complement existing EcoRA decision-support tools with a web-based engine for storing and searching biological tests and methods used in EcoRA as there is currently no similar informational source available on the Internet.

GFP assay as a sensitive eukaryotic screening model to detect toxic and genotoxic activity of azaarenes.

Azaarenes are nitrogen-containing polyaromatic heterocyclic compounds (NPAHs). The majority of the azaarenes found in the environment originate from anthropogenic sources. Concentrations of NPAHs found in the environment are reported to be one to two orders of magnitude lower than polycyclic aromatic hydrocarbons (PAHs) concentrations, yet their biological effects can be of similar magnitude. Very few studies on the genotoxicity of azaarenes are available in the literature. In the present study, a preliminary profile of both the toxic and genotoxic potential of 5 PAHs and their 20 aza-analogues were investigated. To assess the toxic and genotoxic activity, a green fluorescent protein (GFP) assay based on the yeast Saccharomyces cerevisiae was selected. To compare the sensitivity of this eukaryotic short-term assay with bacterial screening tests, the Toxi-Chromotest for toxicity and SOS-Chromotest for genotoxicity assessment were also performed. This comparison indicates that in most cases, the yeast GFP assay is apparently of comparable specificity to the bacterial toxicity or genotoxicity tests with respect to the correlation of positive/negative responses, but much more sensitive with respect to the effective concentration values. In the cases of phenazine, phenanthridine, 1,10-phenanthroline, or 4,7-phenanthroline, one to two orders of magnitude lower IC20 and minimum genotoxic concentration values in the yeast GFP assay were observed. In this study, the authors present evidence that genotoxicity assessment using the yeast GFP assay can provide a simple system to monitor the activity of these environmental pollutants that could possess mutagenic potential at low concentrations.

Environmental xenobiotics and nuclear receptors--interactions, effects and in vitro assessment.

A group of intracellular nuclear receptors is a protein superfamily including arylhydrocarbon AhR, estrogen ER, androgen AR, thyroid TR and retinoid receptors RAR/RXR as well as molecules with unknown function known as orphan receptors. These proteins play an important role in a wide range of physiological as well as toxicological processes acting as transcription factors (ligand-dependent signalling macromolecules modulating expression of various genes in a positive or negative manner). A large number of environmental pollutants and other xenobiotics negatively affect signaling pathways, in which nuclear receptors are involved, and these modulations were related to important in vivo toxic effects such as immunosuppression, carcinogenesis, reproduction or developmental toxicity, and embryotoxicity. Presented review summarizes current knowledge on major nuclear receptors (AhR, ER, AR, RAR/RXR, TR) and their relationship to known in vivo toxic effects. Special attention is focused on priority organic environmental contaminants and experimental approaches for determination and studies of specific toxicity mechanisms.

Mobility, bioavailability, and toxic effects of cadmium in soil samples.

Total concentration is not a reliable indicator of metal mobility or bioavailability in soils. The physicochemical form determines the behavior of metals in soils and hence the toxicity toward terrestrial biota. The main objectives of this study were the application and comparison of three approaches for the evaluation of cadmium behavior in soil samples. The mobility and bioavailability of cadmium in five selected soil samples were evaluated using equilibrium speciation (Windermere humic aqueous model (WHAM)), extraction procedures (Milli-Q water, DMSO, and DTPA), and a number of bioassays (Microtox, growth inhibition test, contact toxicity test, and respiration). The mobility, represented by the water-extractable fraction, corresponded well with the amount of cadmium in the soil solution, calculated using the WHAM (r(2)=0.96, P<0.001). The results of the ecotoxicological evaluation, which represent the bioavailable fraction of cadmium, correlated well with DTPA extractability and also with the concentration of free cadmium ion, which is recognized as the most bioavailable metal form. The results of the WHAM as well as the results of extraction experiments showed a strong binding of cadmium to organic matter and a weak sorption of cadmium to clay minerals.

Mobility and toxicity of metals in sandy sediments deposited on land.

A times series of laboratory experiments were conducted to investigate the effect of land deposition of contaminated sediments on the bioavailability and mobility of metals. Four sandy sediments were sampled at sites expected to have elevated levels of cadmium and zinc. The physical and chemical characteristics and ecotoxicity of sediments, pore waters, and leachates were evaluated after periods ranging from 1 to 45 days of land deposition. Cd and Zn retardation and leaching potential were calculated and this simulation gave good predictions of subsequently observed Cd and Zn mobility. The mobility and leaching of Cd and Zn in the sediments increased with decreasing pH and with decreasing content of organic matter. During the deposition an increase in sediment toxicity to plants and an increase in eluate toxicity to invertebrates were observed. A high rate of water flow through the sediment resulted in a lower toxicity enhancement of the sediments and a higher toxicity enhancement of the eluates. This result suggests that water flow through the sediment reduces the actual toxicity of the upper layer of deposited sediment but at the same time intensifies the risk of groundwater contamination.

Characterization of estrogenic activity of riverine sediments from the Czech Republic.

Extracts of sediments from rivers in an industrialized area in the Czech Republic were used to evaluate suitability of a simple in vitro bioassay system to detect estrogen receptor (ER)-mediated activity in the complex mixture. Total estrogenic activity was detected by measuring luciferase activity in a stably transfected cell line containing an estrogen-responsive element linked to a luciferase reporter gene. For appropriate interpretation of ER-mediated activity, the effect of sediment extracts on the cell cytotoxicity was assessed at the same time. All sediment samples elicited considerable estrogenic activity. Fractionation of the extracts along with bioassay testing and subsequent instrumental analysis allowed the estrogenic fractions to be identified. The Florisil fraction, which was intermediate in polarity, was the most estrogenic. Instrumental analysis documented that the concentration of the degradation products of alkylphenol ethoxylates did not occur at sufficient concentrations to account for the estrogenic activity. Mass-balance calculations and testing of fractions confirmed that certain polycyclic aromatic hydrocarbons (PAHs) or their metabolites were the most likely compounds contributing to estrogenicity. Some other compounds, such as PCNs and PAH derivatives, that were present in the first and second fraction were tested for their potential estrogenic activity. Their ER-mediated activity and contribution to the overall responses of the complex extracts were very low. The concentrations of 17beta-estradiol present in the bioassay media was an important factor for the evaluation of (anti)estrogenicity of single compound(s) or complex mixtures.

Activation or detoxification of mutagenic and carcinogenic compounds in transgenic Drosophila expressing human glutathione S-transferase.

Sensitivity of transgenic Drosophila melanogaster with expression of a human gene encoding the glutathione S-transferase alpha subunit (GSTA1-1) to 1,2:5,6-dibenzanthracene (DBA) and 1,2-dichloroethane (DCE) was investigated in the somatic mutation and recombination test (SMART). We performed the same assay in control transgenic flies expressing the bacterial lacZ gene. Three types of transgenic Drosophila strains carrying GSTA1-1 were used: two transgenic strains homozygous for the second chromosome with a single-copy transgene insertion and one strain with two transgene insertions. Larvae carrying the lacZ gene were significantly more sensitive to genotoxic effects of DBA than those carrying three copies of the GSTA1-1 gene. The larvae with lacZ expression showed significantly lower sensitivity to DCE compared with those expressing GSTA1-1. Finally, a pretreatment with buthionine-sulphoximine (BSO) in experiment with DCE significantly decreased the frequency of mutation events in larvae with three GSTA1-1 copies in comparison with others.

Photodegradation of halobenzenes in water ice.

Results from the photolysis of o, p-dichlorobenzene, bromobenzene, and p-dibromobenzene in water ice are reported. All phototransformations appeared to be based on dehalogenation, coupling, and rearrangement reactions in ice cavities. No photosolvolysis products, i.e. products from intermolecular reactions between organic and water molecules, were found. Many of the products were very toxic substances of a high environmental risk, such as PCBs. The results support our model, in which secondary, very toxic, pollutants can be formed in ice, snow, and atmospheric ice particles from primary pollutants through the action of solar irradiation. The photoproducts may be released to the environment by ice melting and evaporation.

Regional background monitoring of PBT compounds. The comparison of the results from measurements and modelling.

A comparison of the modelling results of persistent, bioaccumulative and toxic (PBT) chemicals is presented with measurements. Contribution will present mean annual concentrations calculated and observed at EMEP stations and their ratios. The comparison of the calculated results with older results indicates that the model modification improved the agreement with measurement data. PBT compounds in ambient air are monitored in the area of Kosetice observatory (professional observatory of the Czech Hydrometeorological Institute located in south Bohemia). Calculated and measured mean annual concentrations of PBTs in precipitation, soil, vegetation and their ratios are presented. It should be mentioned that the number of measurements in such compartments as seawater, soil and vegetation is insufficient for model verification at present. The agreement between results from MSC-East models and results from long-term regional air background monitoring in Central Europe is good.

Monitoring river sediments contaminated predominantly with polyaromatic hydrocarbons by chemical and in vitro bioassay techniques.

Extracts of sediment samples collected from the Morava River and its tributaries (Czech Republic) were examined for mutagenic, dioxin-like, and estrogenic activities. Moreover, the human leukemic HL-60 cell line was tested as a potential model for the detection of effects of environmental contaminants on cell proliferation and differentiation processes. Analytical data indicate that the sediments were contaminated predominantly with polycyclic aromatic hydrocarbons (PAHs) and phthalate esters. The sums of concentrations of 16 U.S. Environmental Protection Agency priority PAHs ranged from 0.8 to 13.2 micrograms/g and those of phthalates reached up to 3,000 ng/g, while only low levels of chlorinated hydrocarbons were found. The main goal of the present study was to determine effects of PAH prevalence on in vitro bioassays, with special emphasis on dioxin-like activity. The dioxin-like activity was tested using a reporter gene assay based on chemical-activated luciferase expression (the CALUX assay). Significant dioxin-like activity (2.6-40.1 micrograms/g benzo[a]pyrene equivalents and 5.9-48.2 ng/g 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents) was detected in all samples, and the results obtained with various exposure times or with both crude and PAH-deprived extracts indicate that the response was probably caused almost exclusively by the presence of high concentrations of PAHs. This corresponds with results of chemical analyses and indicates that various exposure times would allow a discrimination between dioxin-like activities of persistent compounds and easily metabolized aryl hydrocarbon (Ah) receptor inducers. Only sediment extracts containing the highest concentrations of PAHs were mutagenic, as determined by the umu assay. Estrogenic activity was found in several samples (4.75-22.61 pg/g estradiol equivalents) using cells stably transfected with an estrogen-responsive element linked to a luciferase promoter. Noncytotoxic doses of extracts had no effects on HL-60 cell proliferation, while two of the tested crude extracts significantly enhanced their all-trans retinoic acid-induced differentiation. These activities were not associated with phthalate esters and/or PAHs. Our results indicate that cellular and biochemical in vitro assays based on various specific modes of action may yield data complementary to results of mutagenicity tests and that they could be useful in environmental risk assessment. High levels of PAHs are apparently associated with dioxin-like and mutagenic activities rather than with estrogenic activity.

Determination and multivariate statistical analysis of biochemical responses to environmental contaminants in feral freshwater fish Leuciscus cephalus, L.

Modulations of 11 prospective biochemical markers of impacts of aquatic pollutants in liver tissue of chub (Leuciscus cephalus), caught at several sampling sites of a river with various pollution types and rates, were matched against analytical data of concentrations of organochlorine compounds, polycyclic aromatic hydrocarbons (PAHs), and heavy metals. Multivariate principal component analysis (PCA) of the field data showed general patterns of biochemical responses to different types of pollutants and relationships among the biomarkers. Cytochrome P4501A-dependent 7-ethoxyresorufin O-deethylase (EROD) activity, inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin and structurally related planar compounds, was strongly enhanced in the more contaminated areas. Compared with polychlorinated aromatic hydrocarbons, PAHs did not contribute so significantly to EROD induction. Testosterone 6 beta- and 16 alpha-hydroxylase activities, as an expression of the cytochrome P4503A27, were slightly increased at several sites but were significantly decreased in samples from some heavily polluted areas. Recently, these activities have been suggested as potential biomarkers of exposure to contaminants that do not induce cytochrome P4501A. In this study, their inhibition or induction was not associated with a specific class of monitored contaminants, and selectivities of these modulations are still to be investigated. Similar modulations of the prospective biochemical indicators of oxidative stress, including microsomal glutathione S-transferase activity, cytosolic glutathione S-transferase with ethacrynic acid, and glutathione reductase, were demonstrated by PCA. The pattern of the modulations of the microsomal nicotinamide adenine dinucleotide phosphate (NADPH)-dependent lipid peroxidation in vitro differed from the responses of the rest of oxidative stress parameters at some sampling sites. Further biochemical markers of oxidative stress under study, including in vivo lipid peroxidation, in vitro production of reactive oxygen species, and the concentration of metallothioneins did not correlate well with the concentrations of the contaminants. Principal component analysis demonstrated that the EROD activity, glutathione-dependent enzymes, and Fe(II)-enhanced lipid peroxidation formed a suitable battery of biomarkers of exposure.

Persistent, bioaccumulative, and toxic compounds in the central and eastern European countries--the-state-of-the-art report--human exposure.

This review describes problems with persistent and bioaccumulative organic substances which posses toxic characteristics likely to cause adverse human health or environmental effects in countries of Central and Eastern Europe as far as human exposure is concerned. This paper is a part of a more detailed report on the subject.

Persistent, bioaccumulative, and toxic compounds in central and eastern Europe--hot spots.

The sources and environmental levels of the PBTs in the countries of Central and Eastern Europe are broadly described. Most of the countries in the region produce and/or formulate pesticides. The pesticide registration is a primary requirement for import, production and distribution. The special attention must be given to unwanted pesticides. The problem of unwanted and expired pesticides pose the greatest danger to the natural environment and people which is brought about by the use of chemicals in agriculture in CEE countries. Countries still have not solve the problem of safety storage for PBTs and other chemicals classified as poisons and they have no special sites or facilities for destruction of these chemicals. This region has very specific problems of environmental pollution, which are the results of the recent wars. Destruction of industrial facilities and spilling of chemicals have the worst effect for the environment (Bosnia and Herzegovina, Croatia, Serbia and Montenegro).

Characterization of dioxin-like activity of sediments from a Czech river basin.

Synthetic organic chemicals are present in environmental compartments as complex mixtures and therefore their potential effects are difficult to predict. In this study, in vitro bioassays using wild-type fish and rat hepatoma cell lines and their corresponding recombinant cell systems were used to evaluate 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activity in extracts of sediments collected from rivers of the Czech Republic. All the sediment extracts elicited statistically significant responses in all the cell lines tested. For most sediment extracts, a complete dose-response relationship was obtained. The maximal efficacy of the samples was between 57 and 143% of the maximal induction elicited by TCDD. Greater responsiveness, sensitivity, and reproducibility were observed for recombinant than wild-type cells. Cell line-specific differences in the sensitivity to compounds present in the complex sediment extracts were observed. The TCDD equivalents (TCDD-EQs) determined from the different cell bioassays were correlated. Greater concentrations of TCDD-EQs were obtained with fish cell lines. The TCDD-EQs calculated from the results of chemical analysis of toxic equivalents (TEQs) were in good agreement with those determined by bioassays; the arly hydrocaron receptor (AhR)-effects of the identified chemicals appear to be generally additive. This indicates that most of the TCDD-like activity was accounted for by the compounds identified and quantified by instrumental analysis. Fractionation along with mass-balance calculations allowed identification of the active fractions and classes of compounds. Polycyclic aromatic hydrocarbons (PAHs) were found to be responsible for most of the AhR-mediated activity in sediments.

Toxic, bioaccumulative and persistent chemicals in central and eastern Europe--state-of-the-art report.

Organic substances that are persistent, bioaccumulative and have toxic characteristics likely to cause adverse effects on human health or have environmental effects are called PBTs (Persistent, Bioaccumulative, Toxic substances). The report "Persistent, Bioaccumulative and Toxic Chemicals in Central and Eastern European Countries--State-of-the-art Report" was prepared by a group of scientists from the Czech Republic, Slovakia, Poland and Estonia and was published on the Internet (http:¿recetox.chemi.muni.cz/).