PURPOSE: Isoproturon, a herbicide belonging to the phenylurea family, is widely used to kill weeds in soils. Recent study indicated that isoproturon has become a contaminant in ecosystems due to its intensive use, thus bringing environmental risks to crop production safety. Salicylic acid (SA) is one of the components in plant defense signaling pathways and regulates diverse physiological responses to biotic and environmental stresses. The purpose of the study is to help to understand how SA mediates the biological process in wheat under isoproturon stress. METHODS: Wheat seeds (Triticum aestivum, cv. Yangmai 13) were surface-sterilized and placed on moist filter paper for germination. After 24 h, the germinating seeds were placed on a plastic pot (1 L) containing 1,120 g soil mixed with isoproturon at 4 mg kg−1 soil. After 4 days, wheat leaves were sprayed with 5 mg L−1 SA. The SA treatment was undertaken once a day and lasted for 6 days, when the third true leaf was well developed. For control seedlings, only water was sprayed. Seedlings were grown under a light intensity of 300 µmol m−2 s−1 with a light/dark cycle of 12/12 h at 25°C, and watered to keep 70% relative water content in soils. RESULTS AND DISCUSSION: We investigated the role of SA in alleviating isoproturon-induced toxicity in the food crop wheat (T. aestivum). Plants exposed to 4 mg kg−1 isoproturon showed growth stunt and oxidative damage, but concomitant treatment with 5 mg L−1 SA was able to attenuate the toxic effect. Isoproturon in soils was readily accumulated by wheat, but such accumulation can be blocked significantly by SA application. Treatment with SA decreased the abundance of O2 .− and H2O2, as well as activities of antioxidant enzymes, and increased activities of catalase in isoproturon-exposed plants. The enzyme activities were confirmed by the native polyacrylamide gel electrophoresis. Further, an RT-PCR-based assay was performed to show that several transcripts coding antioxidant enzymes were increased with isoproturon but decreased by SA. CONCLUSION: The present results indicate that exogenous SA is able to improve the wheat tolerance to isoproturon toxicity.

INTRODUCTION: Triclosan (TCS) is a multi-purpose biocide. Its wide use in personal care products (PCPs) fosters its dispersal in the aquatic environment. Despite enhanced awareness of both scientists and the public in the last decade with regard to fate and effects, TCS received little attention regarding its prioritisation as a candidate river basin-specific pollutant or even priority substance, due to scarce monitoring data. METHODS: Applying a new prioritisation methodology, the potential risk of TCS was assessed based on a refined hazard assessment and occurrences at 802 monitoring sites in the Elbe River basin. RESULTS: The suggested acute-based predicted no-effect concentration (PNEC) of 4.7 ng/l for the standard test species Selenastrum capricornutum was in good agreement with effect concentrations in algal communities and was exceeded in the Elbe River basin at 75% of the sites (limit of quantification of 5 ng/l). The 95th percentile of the maximum environmental concentrations at each site exceeded the PNEC by a factor of 12, indicating potential hazards for algal communities. Among 500 potential river basin-specific pollutants which were recently prioritised, triclosan ranks on position 6 of the most problematic substances, based on the Elbe River data alone. CONCLUSION: Considering the worldwide application of PCPs containing triclosan, we expect that the TCS problem is not restricted to the Elbe River basin, even if monitoring data from other river basins are scarce. Thus, we suggest to include TCS into routine monitoring programmes and to consider it as an important candidate for prioritisation at the European scale.

INTRODUCTION: A chemometric evaluation has been done to classify metal ions in soils and to determine whether or not the gastric and intestinal phases of a physiologically based extraction test bear any relation to any of the phases of the four-stage Community Bureau of Reference (BCR) extraction protocol. MATERIALS AND METHODS: Nine trace analytes (As, Ba, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were determined in extracts obtained from the BCR sequential extraction procedure as well as from in vitro gastro-intestinal experiments. The results showed that high As, Pb, Zn and Cd concentrations were found in these soils. Principal component analysis (PCA) and linear discriminant analysis were used as classification techniques. Stepwise multiple linear regression analysis was applied to the data set to determine how the bioaccessibility of a metal is linked to the operationally defined fractions of metal speciation in soil. RESULTS AND DISCUSSION: This analysis showed that the metal concentrations in the intestinal and gastric extracts are mainly dependent on the concentrations found in BCR phases 1 and 2 for each metal ion except for Cr, which was mainly dependent on the concentrations found in BCR phase 3. From the chemometric technique of correlation analysis, it was concluded that the metals extracted using BCR phases 1 and 2 are more likely to be bioaccessible, i.e. are also extracted by gastric and intestinal digestion solutions. When the correlation and PCA results were interpreted together, it indicated that the bioaccessiblity of Zn, Pb, Mn and Cd were higher than As, Ba, Cr, Ni and Cu for these soils.

BACKGROUND: In this paper, batch removal of hexavalent chromium from aqueous solutions by Araucaria heterophylla leaves was investigated. The batch experiments were conducted to study the adsorption of metal species and effect of different pH, contact time, metal concentration, biosorbent concentration, and adsorption capacity. METHOD: Freundlich and Langmuir’s isotherm model were used to describe the adsorption behavior, and the experimental results fitted Freundlich model well. RESULTS: The adsorption efficiency observed for all chromium concentrations, i.e., 1, 3, 5, and 10 mg/L was 100% and the equilibrium was achieved in 30 min for 1 and 3 mg/L, whereas for 5 and 10 mg/L, it was less than 60 min. FTIR spectra was taken to identify functional groups involved in the biosorption. CONCLUSION: Thus, Araucaria leaves can be considered as one of the cheap and efficient biosorbent for toxic hexavalent chromium removal from natural or wastewaters.

INTRODUCTION: Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain). METHODS: River fresh water samples were collected twice a week over a period of 5 weeks at three sampling points. Sixty-six pharmaceutical compounds belonging to different therapeutical classes were analyzed by LC-MS/MS. RESULTS AND DISCUSSION: Positive and negative correlations between the concentrations of the target analytes and hydrological variables like river flow and dissolved organic matter were observed pointing out the relevance of different hydrological phenomena like dilution effects or sediment re-suspension. Sensitivity calculations showed that the majority of compounds were sensitive to flow variations

PURPOSE: The aim of this work was to improve the ability of electro-Fenton technique for the remediation of wastewater contaminated with synthetic dyes using a model azo dye such as Azure B. METHODS: Batch experiments were conducted to study the effects of main parameters, such as dye concentration, electrode surface area, treatment time, and voltage. In this study, central composite face-centered experimental design matrix and response surface methodology were applied to design the experiments and evaluate the interactive effects of the four studied parameters. A total of 30 experimental runs were set, and the kinetic data were analyzed using first- and second-order models. RESULTS: The experimental data fitted to the empirical second-order model of a suitable degree for the maximum decolorization of Azure B by electro-Fenton treatment. ANOVA analysis showed high coefficient of determination value (R 2 = 0.9835) and reasonable second-order regression prediction. Pareto analysis suggests that the variables, time, and voltage produce the largest effect on the decolorization rate. CONCLUSION: Optimum conditions suggested by the second-order polynomial regression model for attaining maximum decolorization were dye concentration 4.83 mg/L, electrode surface area 15 cm2, voltage 14.19 V, and treatment time of 34.58 min.

BACKGROUND, AIM, AND SCOPE: 2,2-bis(chlorophenyl)-1,1,1-trichloroethane (DDT) metabolites, other than those routinely measured [i.e., 2,2-bis(chlorophenyl)-1,1-dichloroethylene (DDE) and 2,2-bis(chlorophenyl)-1,1-dichloroethane (DDD)], have recently been detected in elevated concentrations not only in the surface water of Teltow Canal, Berlin, but also in sediment samples from Elbe tributaries (e.g., Mulde and Havel/Spree). This was paralleled by recent reports that multiple other metabolites could emerge from the degradation of parent DDT by naturally occurring organisms or by interaction with some heavy metals. Nevertheless, only very few data on the biological activities of these metabolites are available to date. The objective of this communication is to evaluate, for the first time, the cytotoxicity, dioxin-like activity, and estrogenicity of the least-studied DDT metabolites. METHODS: Four DDT metabolites, p,p′-2,2-bis(chlorophenyl)-1-chloroethylene (DDMU), p,p′-2,2-bis(chlorophenyl)-1-chloroethane (DDMS), p,p′-2,2-bis(4-ch1oropheny1)acetonitrile (DDCN), and p,p′-2,2-bis(chlorophenyl)acetic acid (DDA), were selected based on their presence in environmental samples in Germany such as in sediments from the Mulde River and Teltow Canal. O,p′-DDT was used as reference in all assays. Cytotoxicity was measured by neutral red retention with the permanent cell line RTG-2 of rainbow trout (Oncorhynchus mykiss). Dioxin-like activity was determined using the 7-ethoxyresorufin-O-deetylase assay. The estrogenic potential was tested in a dot blot/RNAse protection-assay with primary hepatocytes from male rainbow trout (O. mykiss) and in a yeast estrogen screen (YES) assay. RESULTS: All DDT metabolites tested revealed a clear dose–response relationship for cytotoxicity in RTG-2 cells, but no dioxin-like activities with RTL-W1 cells. The dot blot/RNAse protection-assay demonstrated that the highest non-toxic concentrations of these DDT metabolites (50 μM) had vitellogenin-induction potentials comparable to the positive control (1 nM 17β-estradiol). The estrogenic activities could be ranked as o,p′-DDT > p,p′-DDMS > p,p′-DDMU > p,p′-DDCN. In contrast, p,p′-DDA showed a moderate anti-estrogenic effect. In the YES assay, besides the reference o,p′-DDT, p,p′-DDMS and p,p′-DDMU displayed dose-dependent estrogenic potentials, whereas p,p′-DDCN and p,p′-DDA did not show any estrogenic potential. DISCUSSION: The reference toxicant o,p′-DDT displayed a similar spectrum of estrogenic activities similar to 17β-estradiol, however, with a lower potency. Both p,p′-DDMS and p,p′-DDMU were also shown to have dose-dependent estrogenic potentials, which were much lower than the reference o,p′-DDT, in both the vitellogenin and YES bioassays. Interestingly, p,p′-DDA did not show estrogenic activity but rather displayed a tendency towards anti-estrogenic activity by inhibiting the estrogenic effect of 17β-estradiol. The results also showed that the p,p′-metabolites DDMU, DDMS, DDCN, and DDA do not show any dioxin-like activities in RTL-W1 cells, thus resembling the major DDT metabolites DDD and DDE. CONCLUSIONS: All the DDT metabolites tested did not exhibit dioxin-like activities in RTL-W1 cells, but show cytotoxic and estrogenic activities. Based on the results of the in vitro assays used in our study and on the reported concentrations of DDT metabolites in contaminated sediments, such substances could, in the future, pose interference with the normal reproductive and endocrine functions in various organisms exposed to these chemicals. Consequently, there is an urgent need to examine more comprehensively the risk of environmental concentrations of the investigated DDT metabolites using in vivo studies. However, this should be paralleled also by periodic evaluation and monitoring of the current levels of the DDT metabolites in environmental matrices. RECOMMENDATIONS AND PERSPECTIVES: Our results clearly point out the need to integrate the potential ecotoxicological risks associated with the “neglected” p,p′-DDT metabolites. For instance, these DDT metabolites should be integrated into sediment risk assessment initiatives in contaminated areas. One major challenge would be the identification of baseline data for such risk assessment. Further studies are also warranted to determine possible additive, synergistic, or antagonistic effects that may interfere with the fundamental cytotoxicity and endocrine activities of these metabolites. For a more conclusive assessment of the spectrum of DDT metabolites, additional bioassays are needed to identify potential anti-estrogenic, androgenic, and/or anti-androgenic effects.

INTRODUCTION: Dissolved organic matter (DOM) is the most active component in environmental system and its chemical and structural characteristics most likely influence its biodegradation. Four surface soil (0–20 cm) and three core sediment samples (0–10 cm) were collected from Wuliangsuhai Lake. The objectives of this study were to investigate the spectral properties and humification degree of DOM and to determine and discuss comparatively the complexing capacities and stability constants of DOM by Cu (II) in the Hetao region. MATERIALS AND METHODS: In this study, fluorescence spectra and fluorescence quenching methods were used to evaluate the humification degree of DOM and calculate the complexing capacities and the stability constants between DOM and Cu (II). RESULTS AND DISCUSSION: Two defined peaks, at wavelengths of 260∼300 nm (peak I) and 300∼350 nm (peak II), could be identified for soil DOM at a Δλ value of 30 nm. In sediment DOM extracts, a third peak (III) was observed near 364 nm. The results show that there is a significant difference in the structure of DOM because of different sources. The humification degree is significantly higher for soil samples than those of sediment samples. The FT-IR spectra of DOM show that structure in sediment DOM is more functional groups than those in soil DOM. DOM has a stronger Cu binding affinity in soils than in sediment in the Hetao region, which may lead to potentially significant influence on the migration and transformation of Cu (II).

BACKGROUND: The state of the art of passive water sampling of (nonpolar) organic contaminants is presented. Its suitability for regulatory monitoring is discussed, with an emphasis on the information yielded by passive sampling devices (PSDs), their relevance and associated uncertainties. Almost all persistent organic pollutants (POPs) targeted by the Stockholm Convention are nonpolar or weakly polar, hydrophobic substances, making them ideal targets for sampling in water using PSDs. Widely used nonpolar PSDs include semi-permeable membrane devices, low-density polyethylene and silicone rubber. RESULTS AND DISCUSSION: The inter-laboratory variation of equilibrium partition constants between PSD and water is mostly 0.2–0.5 log units, depending on the exact matrix used. The sampling rate of PSDs is best determined by using performance reference compounds during field deployment. The major advantage of PSDs over alternative matrices applicable in trend monitoring (e.g. sediments or biota) is that the various sources of variance including analytical variance and natural environmental variance can be much better controlled, which in turn results in a reduction of the number of analysed samples required to obtain results with comparable statistical power. CONCLUSION: Compliance checking with regulatory limits and analysis of temporal and spatial contaminant trends are two possible fields of application. In contrast to the established use of nonpolar PSDs, polar samplers are insufficiently understood, but research is in progress to develop PSDs for the quantitative assessment of polar waterborne contaminants. In summary, PSD-based monitoring is a mature technique for the measurement of aqueous concentrations of apolar POPs, with a well-defined accuracy and precision.

INTRODUCTION: The removal of azo Reactive Red 31(RR31) from synthetic dye solution using tannery sludge-developed activated carbon (TSC) was investigated. METHODS: TSC was prepared from a combination of physical and chemical activation. The developed TSC was characterized by FT-IR, SEM, TG–DTA, specific surface area and zero point charge of pH (pHzpc). The isotherm models, kinetic models and thermodynamic parameters were also analysed to describe the adsorptive behaviour of TSC. The effect of contact time, initial dye concentration, carbon dosage, agitation speed, initial pH and temperature were carried out for batch adsorption studies. The isotherm plot of the dye RR31 on TSC fitted better with the Langmuir adsorption isotherm than the Freundlich model. RESULTS: The maximum monolayer adsorption capacity of TSC in the removal of RR31 ranged from 23.15 to 39.37 mg/g. The thermodynamic parameters showed the endothermic and physical nature of the Reactive Red 31 adsorption on TSC. The entropy and enthalpy values were 181.515 J/Kmol and 5.285 kJ/mol, respectively. CONCLUSION: The developed cationic tannery sludge carbon was found to be an effective adsorbent in the removal of the anionic azo reactive dye RR31.