Use of read-across to simplify the toxicological assessment of a complex mixture of lysimeter leachate metabolites on the basis of chemical similarity and ADME behavior.

This paper describes the further development of a read-across approach applicable to the toxicological assessment of structurally-related xenobiotic metabolites. The approach, which can be applied in the absence of definitive identification of all the individual metabolites, draws on the use of chemical descriptors and multi-variate statistical analysis to define a composite "chemical space" and to classify and characterize closely-related subgroups within this. In this example, consideration of the descriptors driving grouping, combined with empirical evidence for lack of significant further biotransformation of metabolites, leads to the conclusion that, in the absence of any specific structural alerts, the relative toxicity of metabolites within a single grouping will be determined by their relative systemic exposure as described by their ADME characteristics. The in vivo testing of a smaller number of exemplars, selected to have representative ADME properties for each grouping, is sufficient, therefore, to evaluate the toxicity of the remainder. The approach is exemplified using the metabolites of the herbicide S-metolachlor, detected in the leachate of a soil lysimeter.

Carbaryl degradation by bacterial isolates from a soil ecosystem of the Gaza Strip

Abstract Carbaryl is an important and widely used insecticide that pollutes soil and water systems. Bacteria from the local soil ecosystem of the Gaza Strip capable of utilizing carbaryl as the sole source of carbon and nitrogen were isolated and identified as belonging to Bacillus, Morganella, Pseudomonas, Aeromonas and Corynebacterium genera. Carbaryl biodegradation by Bacillus, Morganella and Corynebacterium isolates was analyzed in minimal liquid media supplemented with carbaryl as the only source of carbon and nitrogen. Bacillus and Morganella exhibited 94.6% and 87.3% carbaryl degradation, respectively, while Corynebacterium showed only moderate carbaryl degradation at 48.8%. These results indicate that bacterial isolates from a local soil ecosystem in the Gaza Strip are able to degrade carbaryl and can be used to decrease the risk of environmental contamination by this insecticide.

A comparison of methods used to calculate normal background concentrations of potentially toxic elements for urban soil.

To meet the requirements of regulation and to provide realistic remedial targets there is a need for the background concentration of potentially toxic elements (PTEs) in soils to be considered when assessing contaminated land. In England, normal background concentrations (NBCs) have been published for several priority contaminants for a number of spatial domains however updated regulatory guidance places the responsibility on Local Authorities to set NBCs for their jurisdiction. Due to the unique geochemical nature of urban areas, Local Authorities need to define NBC values specific to their area, which the national data is unable to provide. This study aims to calculate NBC levels for Gateshead, an urban Metropolitan Borough in the North East of England, using freely available data. The 'median + 2MAD', boxplot upper whisker and English NBC (according to the method adopted by the British Geological Survey) methods were compared for test PTEs lead, arsenic and cadmium. Due to the lack of systematically collected data for Gateshead in the national soil chemistry database, the use of site investigation (SI) data collected during the planning process was investigated. 12,087 SI soil chemistry data points were incorporated into a database and 27 comparison samples were taken from undisturbed locations across Gateshead. The SI data gave high resolution coverage of the area and Mann-Whitney tests confirmed statistical similarity for the undisturbed comparison samples and the SI data. SI data was successfully used to calculate NBCs for Gateshead and the median+2MAD method was selected as most appropriate by the Local Authority according to the precautionary principle as it consistently provided the most conservative NBC values. The use of this data set provides a freely available, high resolution source of data that can be used for a range of environmental applications.

Chemical fingerprinting of hydrocarbon-contamination in soil.

Chemical fingerprinting analyses of 29 hydrocarbon-contaminated soils were performed to assess the soil quality and determine the main contaminant sources. The results were compared to an assessment based on concentrations of the 16 priority polycyclic aromatic hydrocarbons pointed out by the U.S. Environmental Protection Agency (EPAPAH16) and total petroleum hydrocarbon (TPH). The chemical fingerprinting strategy proposed in this study included four tiers: (i) qualitative analysis of GC-FID chromatograms, (ii) comparison of the chemical composition of both un-substituted and alkyl-substituted polycyclic aromatic compounds (PACs), (iii) diagnostic ratios of selected PACs, and (iv) multivariate data analysis of sum-normalized PAC concentrations. The assessment criteria included quantitative analysis of 19 PACs and C1-C4 alkyl-substituted homologues of naphthalene, fluorene, dibenzothiophene, phenanthrene, pyrene, and chrysene; and 13 oxygenated polycyclic aromatic compounds (O-PACs). The chemical composition of un-substituted and alkyl-substituted PACs and visual interpretation of GC-FID chromatograms were in combination successful in differentiating pyrogenic and petrogenic hydrocarbon sources and in assessing weathering trends of hydrocarbon contamination in the soils. Multivariate data analysis of sum-normalized concentrations could as a stand-alone tool distinguish between hydrocarbon sources of petrogenic and pyrogenic origin, differentiate within petrogenic sources, and detect weathering trends. Diagnostic ratios of PACs were not successful for source identification of the heavily weathered hydrocarbon sources in the soils. The fingerprinting of contaminated soils revealed an underestimation of PACs in petrogenic contaminated soils when the assessment was based solely on EPAPAH16. As alkyl-substituted PACs are dominant in petrogenic sources, the evaluation of the total load of PACs based on EPAPAH16 was not representative. Likewise, the O-PACs are not represented in soil quality assessments based on EPAPAH16 and TPH. The ∑O-PACs ranged between

[SCIENTIFIC EVIDENCE FOR HYGIENIC STANDARDS HARMONIZED WITH INTERNATIONAL RECOMMENDATIONS FOR PRIORITY POLLUITIONS OF SOILS].

In accordance with international approaches the ranking of permissible levels of chemicals in the soil for the Russian Federation was performed with the use of actual maximum permissible concentration (MPC), there were scientifically substantiated 33 standardsfor 26 substances and their combinations in the soil, differentiatedfor 6 groups offunctional areas for soil use. There is presented the algorithm determining the procedure for the establishment of MPC for unstudied chemicals for various functional areas of soil of populated areas, as well as draft of amendments to existing sanitary-hygienic regulations prior to processing the latter in accordance with modern requirements.

[Carcinogenic risk of polycyclic aromatic hydrocarbons: classification and interpretation of the monitoring]. / Rischio cancerogeno degli idrocarburi policiclici aromatici: classificazioni e interpretazioni del monitoraggio.

The polycyclic aromatic hydrocarbons (PAHs) are widespread contaminants characterized by various chemical, physical and toxic properties. The characterization of occupational and environmental exposures and the use of suitable measurements protocols are very significant because their presence in mixtures and environmental persistency. In the past few years, the knowledge concerning carcinogenicity of PAHs have been reviewed, the mechanisms involved are the interaction of PAH's metabolites with DNA and oxidative damages. The main requirement for research concerns lack of knowledge on reference values and occupational exposure's assessment in particular PAHs sampling methods that can lead to combined measurements of vapor and aerosol mixtures. Aims of this study are to describe a possible occupational sources of PAHs providing also an update of mechanism involved in their carcinogenicity and risk calculation as is done in the TEF approach. The classifications provided by International Agencies and Institutions and the limit values adopted have been reviewed and taken into account.

Decomposition odour profiling in the air and soil surrounding vertebrate carrion.

Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.

A risk-based methodology for ranking environmental chemical stressors at the regional scale.

A "Risk-based Tool for the Regional Ranking of Environmental Chemical Stressors" has been developed, aimed at supporting decision-makers in the identification of priority environmental contaminants, as well as priority areas, to be further assessed. The tool implements a methodology based on a quantitative Weight-of-Evidence approach, integrating three types of information, identified as "Lines-of-Evidence" (LoE), namely: LoE "Environmental Contamination" (including data on chemical contamination in environmental matrices in the region, thus providing information on potential population exposure), LoE "Intake" (including results from human biomonitoring studies, i.e. concentration of chemicals in human biological matrices, thus providing an integrated estimation of exposure) and LoE "Observed Effects" (including information on the incidence of adverse health outcomes associated with environmental exposure to chemicals). A Multi-Criteria Decision Analysis (MCDA) methodology based on fuzzy logic has been developed to support the integration of information related to these three LoEs for each chemical stressor. The tool allows one to rank chemical stressors at different spatial scales, such as at the regional level as well as within each sub-area (e.g., counties). Moreover, it supports the identification of priority sub-areas within the region, where environmental and health data suggest possible adverse health effects and thus more investigation efforts are needed. To evaluate the performance of this newly developed tool, a case-study in the Flemish region (north of Belgium) has been selected. In the case-study, data on soil contamination by metals and organic contaminants were integrated with data on exposure and effect biomarkers measured in adolescents within the framework of the human biomonitoring study performed by the Flemish Centre of Expertise on Environment and Health in the period 2002-2006. The case-study demonstrated the performance of the tool in integrating qualitative and quantitative data with expert judgement for the identification of priority contaminants and areas. The proposed approach proved to be flexible, allowing for the incorporation of individual decision-maker's preferences, and, at the same time, to be transparent since all assumptions and value attributions are traceable.

[Habitat and incidence of respiratory organs diseases in the Samara population].

There was performed the assessment of habitat quality for Samara population. Risk factors for prevalence of respiratory diseases (pneumonia, allergic rhinitis, asthma) in children, teenagers and adults were revealed to be formaldehyde, phenol, hydrogen sulfide in the ambient, cadmium and copper in the soil.

Construction of a chemical ranking system of soil pollution substances for screening of priority soil contaminants in Korea.

The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme.

Application of fuzzy logic and sensitivity analysis for soil contamination hazard classification.

The present article is aimed at illustrating a methodology for a rapid and effective assessment of pollution hazard connected with the presence of uncontrolled landfills. In particular, by means of a fuzzy approach, the criterion adopted allowed a comparison of the results obtained from a cross analysis of some intrinsic characteristics of the single landfills and the territory where they are located. Their identification shows the most relevant environmental problem. Therefore, we have classified each site within a hazard scale enabling us to understand which one requires to be checked more urgently, to do instrumental surveys and, if needed, to do restoration and reclamation. Moreover, the sensitivity analysis we carried out allowed us to identify which is the best membership function belonging and which is the best defuzzification method. That is, in particular, the trapezoidal function and the centroid method. The proposed fuzzy approach, supported by the sensitivity analysis, has revealed to be an important tool for supporting decisions, in order to optimise technical and economic resources.

[Phenotypic characteristics of Pseudomonas putida isolated from different environments]. / Fenotypowe cechy paleczek Pseudomonas putida izolowanych z rónych srodowisk.

Various typing methods have been suggested to differentiate isolates of P. putida species with the aim of developing epidemiological tools. 34 P putida strains were isolated from the samples of crude oil and oil derivates contaminated soil (n=27), biopreparates used for biodegradation of soil contamination (n=3) and hospital materials (n=4). The biochemical typing was assessed using ID32GN tests (bio-Merieux). The strains were grouped into 11 biotypes. Antibiotic-containing discs were used for routine antibiogramsby disc diffusion assay. The strains were most resistant to cefoperazone and ticarcillin (29.4% and 26.5% of strains, respectively). The intracellular esterases of P. putida were separated by polyacrylamide gel electrophoresis and stained with Fast Blue using alpha-naphthyl acetate, beta-naphthyl propionate and indoxyl acetate as substrates. On the basis of the indicators dye migration the electrophoresis process was observed. By calculating the RF (retention factor) the distribution of stripes was obtained with great accuracy. The use of biochemical tests, sensitivity tests and zymotyping provides the possibility to inter- and intraspecies differentiation of P. putida.

Determination of multiple pharmaceutical classes in surface and ground waters by liquid chromatography-ion trap-tandem mass spectrometry.

This paper describes development, optimization and application of analytical method for determination and reliable confirmation of nineteen pharmaceuticals from different therapeutic classes (antibiotics--beta-lactams, cephalosporines, sulfonamides, macrolides and tetracyclines; benzodiazepines; antiepileptics and analgoantipyretics) in surface and ground waters at ng l(-1) levels. Water samples were prepared using solid-phase extraction and extracts were analyzed by liquid chromatography-ion trap-tandem mass spectrometry with electrospray ionization in both positive and negative ionization mode. The efficiency of ten different SPE cartridges to extract diverse compounds from water was tested. The pH-value of the water sample, the volume of elution solvent and the sample volume were optimized. Matrix effect, especially pronounced for cephalexin and metamizole, was eliminated using matrix-matched standards. It was determined that extraction should be performed at pH approximately 7.5, i.e. without pH adjustment, and at pH 3, depending on the analyte. Azithromycin, doxycycline and acetylsalicylic acid must be extracted in acidic environment, whereas extraction of paracetamol, ampicillin, erythromycin and metamizole should be performed without pH adjustment. Repeatability of the method was generally lower than 20%. The estimated limits of detection were in the range from 0.15 to 12.46 ng l(-1). The method was applied to 26 water samples for monitoring of selected drug residues. Results revealed the presence of carbamazepine (80% of water samples), azithromycin (23%), as well as trimethoprim and paracetamol (both 15%). The most striking was the false positive signal of diclofenac in every analyzed water sample. Confirmation of the positive results was performed by repeated injection of the positive sample extracts using confirmatory method with additional transitions.

Speciation, distribution, and transport of mercury in contaminated soils from Descoberto, Minas Gerais, Brazil.

This work describes an investigation of mercury contamination in an abandoned gold mining site in the rural area of Descoberto, Minas Gerais, Brazil, whose inhabitants have reported "silver balls" present in the soil. Different granulometric fractions of soil samples and sedimented material from rainwater retention tanks in this area were analyzed for total mercury, organic matter, and mercury speciation by thermodesorption/atomic absorption spectrometry. The results showed mercury concentrations in the soils in the range of (0.0371-161) mg kg(-1), and the occurrence of Hg(0) oxidation. Some samples had concentrations as high as 90 mg kg(-1) with the majority as Hg(2+), which is important information in order to understand the biogeochemical behavior of mercury in contaminated sites and to apply the appropriate remediation technology. The retention boxes and tank samples showed that fine particles with high mercury content (3.3-90) mg kg(-1) are leached from the contaminated area, which reveals the need for efficient control of this material to prevent the contamination of stream waters. This study is an example that may be useful for other contaminated sites.

Remediating polluted soils.

This review focuses on treatment-based remediation of soils and the acquisition of data to support and monitor this remediation. Only in the last two decades has significant progress been made in regulating for soil pollution, with a parallel development of methodologies for soil assessment and remediation. However, soil complexity remains a problem for pollutant measurements relevant to environmental risk and informative to the design or evaluation of remediation technologies. Understanding the distribution of pollutants between different soil phases and the kinetics of transfer between these pools is fundamental to prediction for these processes; further progress is needed to characterise less accessible pollutant pools and to develop guidelines for their analysis. Available remediation options include physical, chemical and biological treatments, and these options offer potential technical solutions to most soil pollution. However, selecting the most appropriate approach requires detailed information on how pollutants interact with soil physio-chemical properties. Only general information is available as to the effectiveness of specific treatment systems for particular soil type-pollutant combinations. Given the high degree of heterogeneity in physio-chemical characteristics and pollutant distribution of affected soils, prediction of treatment timescales and levels of residual contamination remains a problem. On sites with a range of organic and inorganic pollutants present, combinations of different treatment approaches may offer the best prospect for effective remediation. Further work is needed to provide evidence that residual contamination does not pose significant risk and to evaluate effects of treatments on general soil function in relation to this contamination.

Removal of lead and cadmium by halophilic bacteria isolated from the Dead Sea shore, Jordan.

Ten Gram-positive and Gram-negative bacterial cultures were recovered from nine water, mud, and soil samples from the Dead Sea shore at Suwaymah. They were able to grow at 10% NaCl and at 45 degrees C. Bacterial cultures 6 and 8 were able to grow in nutrient media supplemented with 2250 ppm of Pb. Bacterial cultures 1, 3-6, 9, and 10 were able to grow in nutrient medium supplemented with 1000 ppm of Cd. Atomic absorption spectrometry was used to estimate the absorbed Pb and Cd by bacterial cultures from 5-, 25-, 100-, and 500-ppm stock solutions of both elements. After 2 wk, the results showed that the maximum absorption for Pb was achieved by culture 6 in the following percentages: 79.8%, 70.48%, 89.48%, and 83.39%, respectively. The maximum absorption of the same concentration of Cd was achieved by culture 9 with the following percentages: 69.2%, 32.24%, 44.98%, and 60.0%, respectively. After 3 wk of incubation, the estimated absorption of both heavy metals was achieved by the same cultures (6 and 9), respectively, in the following percentages: 86.8%, 76.72%, 96.25%, and 96.0% for Pb and 82.60%, 93.2%, 92.74%, and 89.79% for Cd. The accumulation of the absorbed metals was found to be maximum in the protoplast of all the cultures. The accumulation at the cell wall was maximum in culture 2, and between the cell wall and the plasma membrane, it was maximum in cultures 2 and 8 for Pb and Cd, respectively.

Estimation of origins of polycyclic aromatic hydrocarbons in size-fractionated road dust in Tokyo with multivariate analysis.

This study aimed to estimate the origins of polycyclic aromatic hydrocarbons (PAHs) in size-fractionated road dust in Tokyo. First, seven categories of PAHs sources were defined: diesel vehicle exhaust, gasoline vehicle exhaust, tire, pavement, asphalt or bitumen, petroleum products excluding tire and asphalt, and combustion products except for those in vehicle engines. The 189 source data of 12-PAHs profiles were classified into 11 groups based on cluster analysis combined with principal component analysis. Next, 18 road dust samples were collected from eight streets in Tokyo and fractionated into four different particle-size-fractions: 0.1-45, 45-106, 106-250, and 250-2000 microm. In order to estimate the contributions of the classified source groups (S1-S11) to PAHs in the road dust, multiple regression analysis was performed with 12-PAH profile of the road dust as dependent variable and average 12-PAHs profiles of the 11 source groups as 11 explanatory variables. Diesel vehicle exhaust, tire and pavement were the major contributors of PAHs in the fractionated road dust. Although the estimated contributions of the 11 source groups varied among the particle-size-fractions, there was no clear and consistent relationship between particle size and the major PAH contributor.

The comet assay as biomarker of heavy metal genotoxicity in earthworms.

The ubiquitous occurring earthworm species, Eisenia fetida, were exposed to nickel chloride to determine whether the heavy metal Ni caused DNA damage, as measured by the comet (single cell gel electrophoresis) assay. Primary cell cultures of earthworm coelomocytes were exposed in vitro and whole animals either in spiked artificial soil water or in spiked cattle manure substrates. Comets formed were scored using mean tail lengths as well as comparing percentages of damage in five different damage classes. The exposure concentrations used for the in vitro exposure (2, 6, and 12 microg/ml) caused the formation of comets of which the mean tail lengths differed significantly (p < 0.05) from those of unexposed controls but not from each other. Coelomocytes from worms exposed in artificial soil water at concentrations of 0.0049, 0.0078, 0.0175, and 0.025 mg/ml formed comets of which the mean tail lengths differed significantly (p < 0.05) between the exposure groups with increasingly longer tail lengths with higher concentration (dose-related response). The tail length means of the comets of the three highest exposure concentrations also differed significantly (p < 0.05) from the controls. No dose-related response was found between comet tail lengths of the three exposure concentrations (60, 240, and 480 mg/kg) used for the worms in the cattle manure substrates, but the mean tail lengths of comets from all three exposure groups differed significantly (p > 0.05) from the controls. The comets formed in cells from animals exposed in artificial soil water and in cattle manure substrates, scored within damage classes, indicated a clear shift with increasing exposure concentrations from low to high damage. Our results indicated DNA single-strand breaks in soil invertebrate cells caused by exposure to a nickel compound, verifying previous findings for mammals which indicated that this heavy metal has genotoxic potential. These results therefore suggest that earthworms may be useful indicator organisms to assess the genotoxic risks of nickel pollution to terrestrial environments and that the comet assay is a useful tool to use as biomarker of genotoxic effects on invertebrates in soil.

Monitoring and classification of PAH toxicity using an immobilized bioluminescent bacteria.

An immobilized recombinant bioluminescent Escherichia coli strain, harboring a lac::luxCDABE fused plasmid, which shows lower bioluminescence levels when cellular metabolism is inhibited, was used to monitor the cellular toxicity of polycyclic aromatic hydrocarbons (PAHs). PAHs, classified as pericondensed (PCPAHs) or catacondensed (CCPAHs) according to their molecular structures, were differentiable according to the response of this biosensor. Only CCPAHs were found to cause cellular toxicity, resulting in a dose-dependent decrease in the bioluminescent output. The induction of cellular toxicity by CCPAHs and PCPAHs was compared with acute toxicity predictions obtained using the quantitative structure-activity relationship (QSAR) model. A good relationship was obtained between the toxicities determined with the bioluminescent response of the immobilized bacterium GC2 and the QSAR model. It was also found that the present study offers a new method of predicting the cellular toxicities of CCPAHs or PCPAHs using this biosensor.