Purpose Besides classical organic pollutants and pesticides, pharmaceuticals and their residues have nowadays become recognized as relevant environmental contaminants. The risks of these chemicals for aquatic ecosystems are well known, but information about the pharmaca-plant interactions and metabolic pathways is scarce. Therefore, we investigate the process of uptake of acetaminophen (N-Acetyl-4-aminophenol) by Brassica juncea, drug-induced defense responses and detoxification mechanisms in different plant parts. Material and methods Hydroponically grown Indian mustard (Brassica juncea L. Czern.) plants were treated with acetaminophen and root and leaf samples were collected after 24, 72, and 168 h of treatment. The uptake of acetaminophen and the formation of its metabolites were analyzed using LC-MS/MS technique and enzyme activities including glutathione S-transferases (GSTs) as well as several plant defense enzymes like catalase, ascorbat peroxidase, peroxidase, and glutathione reductase were assayed spectrophotometrically. Results We determined the uptake and the translocation of acetaminophen, and we tried to identify the steps of the detoxification process by assaying typical enzymes, supposing the involvement of the same- or similar enzymes and reactions as in the mammalian detoxification process. After 24-h exposure, effective uptake and translocation were observed to the upper part of plants followed by two independent conjugative detoxification pathways. Changes in antioxidant defense enzyme activities connected to the defense pathway towards reactive oxygen species indicate an additional oxidative stress response in the plants. Conclusions The major metabolic pathways in mammals are conjugation with activated sulfate and glucuronic acid, while a small amount of acetaminophen forms a chemically reactive and highly toxic, hydroxylated metabolite. We identified a glutathionyl and a glycoside conjugate, which refer to the similarities to mammalian detoxification. Increased GST activities in leaf tissues were observed correlated with the appearance of the acetaminophen-glutathione conjugate which shows the involvement of this enzyme group in the metabolism of acetaminophen in plants to organic pollutants and xenobiotics. High acetaminophen concentrations lead to oxidative stress and irreversible damages in the plants, which necessitates further investigations using lower drug concentrations for the deeper understanding of the induced detoxification—and defense processes.

Background, aim, and scope Olive oil mill wastewater (OOMW) environmental impacts minimization have been attempted by developing more effective processes, but no chemical or biological treatments were found to be totally effective to mitigate their impact on receiving systems. This work is the first that reports simultaneously the efficiency of three different approaches: biological treatment by two fungal species (Trametes versicolor or Pleurotus sajor caju), enzymatic treatment by laccase, and chemical treatment by photo-Fenton oxidation on phenols removal. Materials and methods Those treatments were performed on OOMW with or without phenol supplement (p-coumaric, vanillin, guaiacol, vanillic acid, or tyrosol). OOMW samples resulted from treatments were extracted for phenols using liquid-liquid extraction and analyzed by gas chromatography coupled to mass spectrometry. Results Treatment with T. versicolor or P. sajor caju were able to remove between 22% and 74% and between 8% and 76% of phenols, respectively. Treatment by laccase was able to reduce 4% to 70% of phenols whereas treatment by photo-Fenton oxidation was responsible for 100% phenols reduction. Discussion Range of phenol degradation was equivalent between T. versicolor, P. sajor caju and laccase for p-coumaric, guaiacol, caffeic acid, and tyrosol in supplemented OOMW, which enhances this enzyme role in the biological treatment promoted by these two species. Conclusions Phenols were removed more efficiently by photo-Fenton treatment than by biological or enzymatic treatments. Recommendations and perspectives Use of fungi, laccase, or photo-Fenton presents great potential for removing phenols from OOMW. This should be further assessed by increasing the application scale and the reactor configurations effect on the performance, besides a toxicity evaluation of treated wastewater in comparison to raw wastewater.

Background, aim, and scope This review deals with publications concerning the mode of action of Bt proteins and their potential synergism with extrinsic factors. The aim was to assess the impact of those factors especially regarding selectivity and efficacy of Bt toxins and to discuss possible gaps in current risk assessment of genetically engineered plants expressing Bt toxins. Main features The review shows that several extrinsic factors are able to influence the selectivity and efficacy of Bt toxins. The findings are seen as being relevant for risk assessment in Bt plants. This conclusion is derived by discussing current state of knowledge about the mode of action of Bt proteins, unexpected effects on non-target organism, and the way how modified Bt toxins are expressed in genetically engineered plants. Results Several publications have been identified that show that certain factors and synergism can impact efficacy and selectivity of Bt toxins. These extrinsic factors are various and include other Bt toxins or parts from the spore of Bacillus thuringiensis as well as certain enzymes, environmental stress, non-pathogenic microorganisms, and infectious diseases. Discussion Research on the underlying mechanism of observed synergism might help to explain some of the effects found in non-target organisms. In general, possible synergism of Bt toxins with extrinsic factors can be relevant for risk assessment of genetically engineered Bt plants since they expose a modified Bt toxin to the environment under various conditions and over a long period of time. Conclusions Risk assessment of genetically engineered plants should put into question the general assumption of a high selectivity and a linear dose-response relationship in the toxicity of Bt proteins. Both selectivity and efficacy can be influenced by synergism, which can provoke unexpected and undesired effects in non-target organisms. Perspectives It is suggested that systematic research be promoted on synergism between Bt toxins and potential extrinsic factors that could impact the spectrum of susceptible organisms. This research should become a prerequisite for risk assessment of Bt plants.

Background, aim, and scope Phosphorus loss from terrestrial to the aquatic ecosystems contributes to eutrophication of surface waters. To maintain the world's vital freshwater ecosystems, the reduction of eutrophication is crucial. This needs the prevention of overfertilization of agricultural soils with phosphorus. However, the methods of risk assessment for the P loss potential from soils lack uniformity and are difficult for routine analysis. Therefore, the efficient detection of areas with a high risk of P loss requires a simple and universal soil test method that is cost effective and applicable in both industrialized and developing countries. Materials and methods Soils from areas which varied highly in land use and soil type were investigated regarding the degree of P saturation (DPS) as well as the equilibrium P concentration (EPC₀) and water-soluble P (WSP) as indicators for the potential of P loss. The parameters DPS and EPC₀ were determined from P sorption isotherms. Results Our investigation of more than 400 soil samples revealed coherent relationships between DPS and EPC₀ as well as WSP. The complex parameter DPS, characterizing the actual P status of soil, is accessible from a simple standard measurement of WSP based on the equation [graphic removed] . Discussion The parameter WSP in this equation is a function of remaining phosphorous sorption capacity/total accumulated phosphorous (SP/TP). This quotient is independent of soil type due to the mutual compensation of the factors SP and TP. Thus, the relationship between DPS and WSP is also independent of soil type. Conclusions The degree of P saturation, which reflects the actual state of P fertilization of soil, can be calculated from the easily accessible parameter WSP. Due to the independence from soil type and land use, the relation is valid for all soils. Values of WSP, which exceed 5 mg P/kg soil, signalize a P saturation between 70% and 80% and thus a high risk of P loss from soil. Recommendations and perspectives These results reveal a new approach of risk assessment for P loss from soils to surface and ground waters. The consequent application of this method may globally help to save the vital resources of our terrestrial and aquatic ecosystems.

Background, aim, and scope Glutaraldehyde (GA) often acts as an effective sterilant, disinfectant, and preservative in chemical products. It was found that GA had clearly acute toxicity to aquatic organisms. Furthermore, GA in natural environment could not exist as single species but as complex mixtures. To explore the toxicity interaction between GA and the other environmental pollutant, it is necessary to determine the mixture toxicities of various binary mixtures including GA. Two reference models, concentration addition (CA) and independent action (IA), are often employed to evaluate the mixture toxicity, which can be finished by comparing the concentration-response curves (CRCs) predicted by the reference models with the experimental CRC of the mixture. However, the CRC-based method cannot effectively denote the degree of the deviations from the reference models, especially at very low effect levels. Though the model deviation ratio (MDR) can be used to quantitatively evaluate the deviation of a mixture at EC50 level from the reference model, it is difficult to evaluate the deviations at the lower effect levels. Therefore, the primary aim of this study was to develop a new effect residual ratio (ERR) method to validate the deviations from the reference models at various effect levels. Materials and methods Four chemicals having possible dissimilar mode of actions with GA, acetonitrile (ACN), dodine (DOD), simetryn (SIM), and metham sodium (MET), were selected as another component in the binary mixtures including GA, which constructed four binary mixtures, GA-ACN, GA-DOD, GA-SIM, and GA-MET ones. For each binary mixture, two equipotent mixture rays where the concentration ratios of GA to another mixture component are respectively EC50 and EC5 ones were designed and their toxicities (expressed as a percent inhibition to Photobacterium phosphoreum) were determined by microplate toxicity analysis. The observed concentration-response curve (CRC) of a ray was compared with that predicted by CA or IA model to qualitatively assess the toxicity interaction of the mixture ray. To quantitatively and effectively examine the deviations at various effect levels from the reference models, a new concept, ERR at an effect, was defined, and the ERR was employed to evaluate the deviation at various effects with confidence intervals. Results For three binary mixtures, GA-ACN, GA-DOD, and GA-SIM, the CRCs predicted by IA models were almost located in the 95% confidence intervals of the experimental CRCs for both equipotent mixture rays, which indicated the independent actions between binary mixture components. However, two rays of GA-MET binary mixture displayed a little synergistic action because both CRCs predicted by CA and IA were lower than the experimental CRC. ERR showed the same results as MDR, but ERR results at low effect area were clearer than MDR ones. Discussion In CRC comparison, the deviation of CA (for GA-ACN, GA-DOD, and GA-SIM combinations) or IA (for GA-MET) model from the experimental values could be obviously observed at medium area of the CRC. However, at very low effect levels, both deviations of CA and IA and difference between CA and IA model predictions were not very apparent. Thus, it was difficult to confirm which model, CA or IA, had better predicted power at very low effect levels. MDR in many literatures often refers to a ratio at EC50 level. It was also difficult to reflect not only the deviation fact at the other ECx but also the deviation uncertainty. After we extended the definition of MDR to all ECx and examined the 95% confidence intervals based on observation, the plot of the redefined MDRs at many effect levels could better explain the deviations of CA or IA model from the observation. However, MDRs at very low effect levels did not still reflect the high uncertainty there. The ERRs defined in our paper could explicitly explain the degree of deviation from the reference models and especially reflect the high uncertainty at very low effects. It could be said that the ERR is a better indicator than MDR. Conclusions The new ERR validation method developed in our laboratory could provide us with the information about the toxicity interaction between the mixture components and quantitatively assess the accuracy of the reference models (CA or IA) at whole effect levels. The ERR method conquered the invalidation of the classical CRC comparison method on the deviation decision at low effect levels and also got the advantage over the MDR methods. Recommendations and perspectives It holds promise to become an effective method of hazard and risk assessments of chemical mixtures by well characterizing the uncertainty at very low effect levels.

Background, aim, and scope Experimental data on partition coefficients and environmental half-lives of sulfur analogs of polychlorinated organic compounds are scarce. Consequently, little is known about their overall persistence and long-range transport potential, which are the most vital measures in the environmental exposure assessment. We performed Multimedia Modeling of environmental fate and transport to complement this paucity of scientific data. The main aim of our study was to investigate whether the sulfur analogs of polychlorinated dibenzo-p-dioxins, -dibenzofurans, and -diphenylethers are as environmentally persistent and/or mobile as their oxygen counterparts and to propose the environmental exposure-related classification of the examined sulfur compounds. Materials and methods Our study included all possible congeners of the sulfur analogs generated in a combinatorial approach. We predicted (1) lacking data on partition coefficients (log K OW, log K OA and log K AW) for oxygen- and sulfur analogs using Quantitative Structure-Property Relationship (QSPR) modeling and (2) their half-lives in air, water, and soil using US EPA tool ‘The PBT Profiler, v. 1.203 2006'. Subsequently, we introduced these results into multimedia mass balance model ‘The OECD POV and LRTP Screening Tool, v. 2.2'. Results Our study revealed that log K OW and log K OA are increasing by constant values of 0.60 and 1.07, respectively, and the values of log K AW are decreasing by 0.90, whenever one oxygen atom in the carbon skeleton is replaced by sulfur. The persistence ranking performed by the PBT Profiler showed that PCDDs, PCDFs, PCDEs, and their sulfur analogs belong to one half-life class. Discussion The Multimedia Modeling by the means of ‘The OECD POV and LRTP Screening Tool, v. 2.2' suggested that the long-range transport potential depends on the presence/absence of oxygen/sulfur atoms in particular molecules, their substitution pattern and the parent carbon skeleton. Sulfur analogs are generally less mobile than their oxygen analogs, but have similar overall persistence and much higher bioaccumulation potential. Thus, according to the classification of chemicals proposed by Klasmeier et al. (Environ Sci Technol 40:53-60, 2006), some of them show POP-like POV and LRTP characteristics while the rest shows POP-like POV characteristics. Conclusions The sulfur analogs of PCDDs, PCDFs, or PCDEs bring environmental mobility comparable with the risk related to the oxygen ones; they belong to the pollutants of ‘highest' or ‘intermediate' priority. Recommendations and perspectives Further studies that would verify the necessity to include the studied sulfur molecules in the international lists of high-priority environmental pollutants are recommended.

Purpose Experiments were conducted to examine the effects of mercury (Hg) on soil nitrification activities and the microbial communities of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Methods The soil samples spiked with different Hg concentrations were incubated for a period of 1, 2, 4, and 8 weeks in triplicate and the potential nitrification rate (PNR) of the samples was determined. The abundance of AOB and AOA was measured after an 8-week incubation by real-time polymerase chain reaction (PCR) assay of the amoA genes, while the community compositions by cloning and sequencing approaches. Results The soil PNR differed with different incubation periods. It tended to decrease with increasing soil Hg concentrations at week 1, basing on which the half-maximal effective concentration (EC50) was 1.59 mg kg⁻¹. There was no significant difference in the abundance of AOB or AOA among the treatments. The AOB community was dominated by Nitrosospira-like sequences and more than 70% of the obtained clones were affiliated with the cluster 3a.2. The percentage of cluster 3a.1 in AOB community appeared to a consistent trend of decreasing with ascending soil Hg concentrations. While all the AOA sequences in the clone libraries were grouped into cluster S (soil and sediment origin). Conclusions This study revealed that Hg could inhibit soil potential nitrification and the extent varied with incubation periods. Soil Hg pollution changed the composition of soil AOB to some extent. These findings will be helpful to recognize the effects of Hg on the activity and community composition of soil ammonia oxidizers.

Purpose The aim of this study was to compare the level of metal contamination in two bays in the middle part of the Eastern Adriatic coastal zone in Croatia using the gills of mussels Mytilus galloprovincialis as indicator tissue. Despite the existing sources of contamination, previous studies with caged mussels only indicated moderate metal contamination of the Kaštela Bay, contrary to the Trogir Bay in which marina and shipyard present a probable source of Cu- and Zn-contamination. Methods The measurements of metallothioneins (MTs) and metals that induce MT synthesis (Cu, Zn, and Cd) were performed in the heat-treated gill cytosol and total proteins (TPs) in the untreated gill cytosol. MTs were determined by differential pulse voltammetry, Cu and Zn by flame atomic absorption spectrometry (AAS), Cd by graphite furnace AAS, and TPs by Bradford spectrophotometric procedure. Results The results collected in four sampling campaigns (autumn periods from 2001 to 2004) indicated that MT levels in mussel gills (expressed on dry mass basis 2.3 ± 0.3 mg g⁻¹) were comparable with basal levels reported in the literature (2.5 ± 0.8 mg g⁻¹). Observed interindividual, temporal, and spatial MT variability could be associated with different confounding factors, such as the time of sampling, total protein concentration, and mussel size rather than cytosolic levels of Cu and Zn. Metal levels, expressed on wet mass basis, in the heat-treated gill cytosol ranged from 1.33 to 11.31 μg g⁻¹ for Zn, from 0.72 to 2.96 μg g⁻¹ for Cu, and from 0.036 to 0.100 μg g⁻¹ for Cd. The highest Zn level was measured at Vranjic (Kaštela Bay)—the site influenced by untreated domestic wastewater, while somewhat increased Zn and the highest Cu levels were found at marina and shipyard locations (Trogir Bay). The highest Cd level was measured at Inavinil (Kaštela Bay). Conclusions The observed association of gill MT levels with several biotic and abiotic factors limits its use as the biomarker of low-level metal exposure. Therefore, the use of the metal concentrations in the heat-treated gill cytosol of Mediterranean mussels should be considered for the assessment of the low-level metal contamination of coastal marine areas.

Background, aim and scope Precipitation samples collected from 1995 to 2000 at meteorological station in the eastern outskirts of Herceg Novi (Montenegro) were analysed on Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, SO₄ ²⁻, NO₃ ⁻ and NH₄ ⁺. Four-day backward trajectory simulations were conducted during the precipitation period to investigate the regional transport of main ions and their deposition in the region of the southeastern Adriatic Sea. The air mass trajectories were classified into six trajectory categories by the origin and direction of their approach to Herceg Novi. Materials and methods A bottle and funnel with a small net between them was used for sampling at a height of 1.5 m above the ground. The concentrations of Cl⁻, NO₃ ⁻, NH₄ ⁺ and SO₄ ²⁻ were determined spectrophotometrically, the concentrations of Na⁺ and K⁺ were determined by the FAES method and the concentrations of Mg²⁺ and Ca²⁺ by the FAAS method. The factor analysis technique (PCA analysis) based on the calculation of the factors was employed to differentiate the contribution of emission sources to the content of the main ions in the precipitation. The obtained data sets were processed using the SPSS 11.5 statistical program. The Hybrid Single-Particle Lagrangian Integrated Trajectory model was used to study the air origin for the city of Herceg Novi (42°27′N, 18°33′E), Montenegro. Discussion The following origins of the air masses were considered: northern Europe (NE), eastern Europe-northeastern Europe (EE-NE); eastern Mediterranean-southeastern Europe (EM-SE); Africa-Central Mediterranean (A-CM); western Mediterranean (WM); western Europe-Central Europe (WE-CE) and undefined. The heights and frequencies of precipitation coming by air masses from northern Europe and eastern-northeastern Europe are the lowest. On the contrary, the heights and frequencies of precipitation coming by air masses from the western Mediterranean (36.6%) and Africa and the Central Mediterranean (30.6%) are the highest. The sea salt components (Na⁺, Cl⁻, Mg²⁺) are significantly correlated, except for air masses originating from the northern and eastern European regions. Significant correlations between SO₄ ²⁻ and NO₃ ⁻ are found in air masses coming from the western Europe and North Africa, over the Mediterranean. Conclusions The highest volume-weighted mean (VWM) of: SO₄ ²⁻ , NH₄ ⁺ and Mg²⁺ are for precipitation from EE-NE while the highest values of VWM of Cl ⁻ are from WM and of K⁺ are from WE-CE. Long-range transport of Sahara dust is confirmed. Recommendations and perspectives For better estimation of origins of water-soluble ions in precipitation expanding list of analysis on anions of organic acids, such as HCOO⁻, CH₃COO⁻, and C₂H₂COO⁻, could be indicative of volatile organic compounds emitted by vegetation but also traffic. The chemical composition of precipitation together with a study of air backward trajectories is the proper tool for tracking the long-range transport of water-soluble ions and estimating transboundary pollution.

Background The Atacama Desert in Northern Chile is one of the most arid places on earth. However, fog occurs regularly at the coastal mountain range and can be collected at different sites in Chile to supply settlements at the coast with freshwater. This is also planned in the fog oasis Alto Patache (20°49′S, 70°09′W). For this pilot study, we collected fog water samples in July and August 2008 for chemical analysis to find indications for its suitability for domestic use. Methods Fog water samples were taken with a cylindrical scientific fog collector and from the net and the storage tank of a Large Fog Collector (LFC). Results The pHs of advective fog, originating from the stratus cloud deck over the Eastern Pacific, varied between 2.9 and 3.5. Orographic fog, which was formed locally, exhibited a pH of 2.5. About 50% of the total ionic concentration was due to sea salt. High percentages of sulfate and very high enrichment factors (versus sea salt) of heavy metals were found. Both backward trajectories and the enrichment factors indicate that the high concentrations of ions and heavy metals in fog were influenced by anthropogenic activities along the Chilean Pacific Coast such as power plants, mining, and steel industry. Conclusions We found no direct indication for the importance of other sources such as the emission of dimethyl sulfide from the ocean and subsequent atmospheric oxidation for acidity and sulfate or soil erosion for heavy metal concentrations. When fog water was collected by the LFC, it apparently picked up large amounts of dry deposition which accumulated on the nets during fog-free periods. This material is rinsed off the collector shortly after the onset of a fog event with the water collected first. During the first flush, some concentrations of acidity, nitrate, As, and Se, largely exceeded the Chilean drinking water limits. Before any use of fog water for domestic purpose, its quality should be checked on a regular basis. Strategies to mitigate fog water pollution are given.