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The potential spreading of antibiotic resistance genes (ARG) into agricultural fields and crops represent a fundamental limitation on the use of organic fertilization in food production systems. We present here a study of the effect of spreading four types of organic soil amendments (raw pig slurry, liquid and solid fractions, and a digested derivative) on demonstrative plots in two consecutive productive cycles of corn harvest (Zea mays), using a mineral fertilizer as a control, following the application of organic amendments at 32-62 T per ha (150 kg total N/ha) and allowing 5-8 months between fertilization and harvest. A combination of qPCR and high-throughput 16S rDNA sequencing methods showed a small, but significant impact of the fertilizers in both ARG loads and microbiomes in soil samples, particularly after the second harvesting cycle. The slurry solid fraction showed the largest impact on both ARG loads and microbiome variation, whereas its digestion derivatives showed a much smaller impact. Soil samples with the highest ARG loads also presented increased levels of tetracyclines, indicating a potential dual hazard by ARG and antibiotic residues linked to some organic amendments. Unlike soils, no accumulation of ARG or antibiotics was observed in corn leaves (used as fodder) or grains, and no grain sample reached detection limits for neither parameter. These results support the use of organic soil amendments in corn crops, while proposing the reduction of the loads of ARGs and antibiotics from the fertilizers to greatly reduce their potential risk., This work was supported by grants from the LIFE Program of the European Union (LIFE17 ENV/ES/000439), the Spanish Ministry of Science, Innovation and University (MCIN/AEI/10.13039/501100011033, grant RTI2018-096175-B-I00), and the Generalitat de Catalunya (2017SGR902). CSL was supported by a FI predoctoral fellowship from the Generalitat de Catalunya and the European Social Fund (2018 FI B 00368, ESF Investing in your future). IDAEA-CSIC is a Center of Excellence Severo Ochoa (Spanish Ministry of Science and Innovation, Project CEX2018-000794-S, ERDF A way of making Europe).

Groundwater pollution has increased in recent years due to the intensification of agricultural and livestock activities. This results in a significant reduction in available freshwater resources. Here, we have studied the long term assessment of a green technology (1-4 L/day) based on a photobioreactor (PBR) containing immobilised microalgae-bacteria in polyurethane foam (PF) followed by a cork filter (CF) for removing nitrates, pesticides (atrazine and bromacil), and antibiotics (sulfamethoxazole and sulfacetamide) from groundwater. The prototype was moderately effective for removing nitrates (58%) at an HRT of 8 days, while its efficiency decreased at a HRT of 4 and 2 days (, The authors wish to thank the financial support of the European Union through the project LIFE18 ENV/ES/000199 and the Spanish Ministry of Science, Innovation and Universities through Project CTM2017-91355-EXP. Finally, European Commission (Erasmus program) and Government of Chile for supporting Lorenzo Rambaldo and Héctor Avila Cortés's visit at IDAEA-CSIC in Barcelona, Spain.

Water quality and riparian communities are among the most affected stream components by agriculture. However, little is known about the effects of riparian management for both aquatic and terrestrial taxa at different spatial scales. Here, we surveyed aquatic (diatoms) and terrestrial taxa (bryophytes, vascular plants, litter-dwelling snails, and ground and volant arthropods), to compare the abundance and richness of riparian taxa and chemical quality between reference and exposed sites in two stream reaches each of c. 3.5 km in northwestern Spain. Impacts in exposed sites were mainly due to traditional farming practices (TFPs), which included traditional meadow management, weirs built for now-unused water mills and sporadic timber harvesting. Therefore, we measured ten covariates and predictors related to the intensification of TFPs at local and within-stream scales and explored associations with riparian and water-quality measures to study the potential effects of TFPs in more detail. Reference and exposed sites did not differ significantly in water properties (diatom-biotic indices, conductivity, total organic carbon and nitrates), but exposed sites had less concentrations of soil metals Cd, Cu, Ni and Zn and less cover and richness of riparian trees, as inferred by the index QBR. Exposed sites had more volant insect decomposers and reference sites a greater abundance or richness of snails, ground predators and decomposers. Bryophyte richness was greater in reference sites. Our inferences may inform the joint cumulative downstream effects of weirs, meadow uses and riparian alterations but were generally consistent with most riparian taxa benefiting from having larger forested areas. Given the contrasting responses among taxa, we argue that land snails, terrestrial flies, and centipedes may be valuable additions to current riparian assessments mostly based on plants, beetles and spiders as indicator taxa. Our study also suggests caution when inferring farming impacts on streams from the surface area of pastoral land., We thank the family of AMV for helping him with the field work. We also thank Miguel Carles-Tolrà because of his generosity declining co-authory despite having identified all the flies. This study was funded by AMV personal funds to set the scientific foundations for the creation of the 'Observatorio AgroFluvial O Incio'.

The spread of antibiotic resistance genes (ARG) into agricultural soils, products, and foods severely limits the use of organic fertilizers in agriculture. In order to help designing agricultural practices that minimize the spread of ARG, we fertilized, sown, and harvested lettuces and radish plants in experimental land plots for two consecutive agricultural cycles using four types of fertilizers: mineral fertilization, sewage sludge, pig slurry, or composted organic fraction of municipal solid waste. The analysis of the relative abundances of more than 200,000 ASV (Amplicon Sequence Variants) identified a small, but significant overlap (, This work was supported by grants from the Spanish Ministry of Science, Innovation and University (MCIN/AEI/10.13039/501100011033, grants RTI2018-096175-B-I00 and AGL2017-89518-R), and the Generalitat de Catalunya (2017SGR902). CSL was supported by a FI predoctoral fellowship from the Generalitat de Catalunya and the European Social Fund (2018 FI B 00368, ESF Investing in your future). IDAEA-CSIC is a Centre of Excellence Severo Ochoa (Spanish Ministry of Science and Innovation, Project CEX2018-000794-S, ERDF A way of making Europe).

While the presence of antibiotic resistance genes (ARGs) in agricultural soils and products has been firmly established, their distribution among the different plant parts and the contribution of agricultural practices, including irrigation with reclaimed water, have not been adequately addressed yet. To this end, we analyzed the levels of seven ARGs (sul1, blaTEM, blaCTX-M-32, mecA, qnrS1, tetM, blaOXA-58), plus the integrase gene intl1, in soils, roots, leaves, and fruits from two commercial tomato fields irrigated with either unpolluted groundwater or from a channel impacted by treated wastewater, using culture-independent, quantitative real-time PCR methods. ARGs and intl1 sequences were found in leaves and fruits at levels representing from 1 to 10% of those found in roots or soil. The relative abundance of intl1 sequences correlated with tetM, blaTEM, and sul1 levels, suggesting a high horizontal mobility potential for these ARGs. High-throughput 16S rDNA sequencing revealed microbiome differences both between sample types (soil plus roots versus leaves plus fruits) and sampling zones, and a correlation between the prevalence of Pseudomonadaceae and the levels of different ARGs, particularly in fruits and leaves. We concluded that both microbiome composition and ARGs levels in plants parts, including fruits, were likely influenced by agricultural practices. © 2018, This work was supported by the European Union's Horizon 2020 research and innovation programme under the H2020 Marie Skłodowska-Curie Actions grant agreement No 675530 . Disclaimer: The content of this article reflects only the authors' views and the Research Executive Agency is not responsible for any use that may be made of the information it contains. Appendix A

The uptake of a large variety of contaminants of emerging concern (CECs) by crops has already been reported, and the occurrence of phase II metabolites or conjugates has only been detected in plant cell cultures. However, the extent of their formation under cropping conditions is largely unknown. In this study, an analytical strategy to assess the conjugation of 11 CECs in lettuce (Lactuca sativa L.) irrigated with different concentrations (0, 0.05, 0.5, 5, and 50 μg L−1) of CECs was developed. The methodology involved enzymatic digestion with β-glucosidase to obtain the total fraction (free form + conjugates) of CECs. The conjugation fraction was then obtained based on the difference. The highest extent of conjugation (i.e., 27 to 83%) was found with the most hydrophobic compounds, such as bisphenol A, carbamazepine, methyl paraben, and triclosan. So, the CEC conjugate fraction cannot be neglected in the estimate of human daily intake.

In this work, analytical strategies were applied aiming at determining sources and ecological risk of PAHs in river sediments. A total of 23 PAHs (16 EPA + 7 alkylated derivatives) were determined in sediment samples. The concentration of total PAH (∑ 23 PAH) span from 0.260 to 2.10 μg g − 1 dw. The molecular ratios indicated a prevalence of pyrolytic pollution sources due to wood combustion processes and refined oil products. The ecological risk was assessed by considering the Sediment Quality Guidelines (SQGs). It was noted that all of the individual PAH concentrations are below the ERM (average variation effect). The ∑ 23 PAH was also below the total of ERL (low variation effect) from 4.02 μg g − 1 dw. The synergy between individual PAHs was assessed using the indices of quality (mSQGq). Accordingly, the risk associated with the simultaneous contamination of the total PAH varied from low to moderate for the different sediments samples of river. The river is located in the state of Bahia, in a region that concentrates the first and largest integrated industrial complex of Brazil.

The use of treated wastewater for crop irrigation is rapidly increasing to respond to the ever-growing demands for water and food resources. However, this practice may contribute to the spread of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in agricultural settings. To evaluate this potential risk, we analyzed microbiomes and resistomes of soil and Lactuca sativa L. (lettuce) root samples from pots irrigated with tap water spiked with 0, 20, or 100 μg L of a mixture of three antibiotics (Trimethoprim, Ofloxacin, Sulfamethoxazole). The presence of antibiotics induced changes in bacterial populations, particularly in soil, as revealed by 16S rDNA sequence analysis. Parallel shotgun sequencing identified a total of 56 different ARGs conferring resistance against 14 antibiotic families. Antibiotic -treated samples showed increased loads of ARGs implicated in mutidrug resistance or in both direct and indirect acquired resistance. These changes correlated with the prevalence of Xantomonadales species in the root microbiomes. We interpret these data as indicating different strategies of soil and root microbiomes to cope with the presence of antibiotics, and as a warning that their presence may increase the loads of ARBs and ARGs in edible plant parts, therefore constituting a potential risk for human consumers., Francisco Cerqueira acknowledges the staff from the Agricultural Research Institute and NIREAS Research Center for their support during his secondment at the University of Cyprus, and making the experiment possible.

Antibiotic resistance (AR) is becoming a worldwide threat due to the increasing occurrence of antibiotic-resistant pathogenic bacterial strains. There is a general consensus about the potential implications of the use of antibiotics in livestock on the onset of antibiotic resistant bacteria (ARB), mainly through meat consumption. However, the ever-increasing use of reclaimed wastewater (RWW) in agriculture may also contribute significantly to the non-accounted exposure to antibiotics, ARB, and antibiotic resistance genes (ARGs). This position paper aims at evaluating the current knowledge concerning the occurrence of antibiotics, ARBs, and ARGs in edible parts of different common crops irrigated with RWW. We will discuss which regulations on the use of RWW may contribute to the minimization of the prevalence of these contaminants in crops, and provide recommendations on how to minimize the impact of these practices., The authors would like to acknowledge the COST Action ES1403 NEREUS “New and emerging challenges and opportunities in wastewater reuse”, supported by COST (European Cooperation in Science and Technology, www.cost.eu) for enabling the collaboration among the authors of the paper.

The application of sewage sludge to agricultural fields reduces the need for mineral fertilizers by increasing soil organic matter, but may also increase soil pollution. Previous studies indicate that zinc and copper, as the most abundant elements in sewage sludge, affect plant uptake of other contaminants. This paper aims to investigate and compare the effect of increasing amounts of Zn and Cu in sludge-amended soils on the accumulation of trace elements (TEs), antibiotics (ABs), and antibiotic resistance genes (ARGs) in lettuce and radish. The vegetables were grown under controlled conditions, and the influence on plant physiology and human health were also evaluated. The results show that the addition of Zn and Cu significantly increased the concentration of TEs in the edible tissue of both vegetables. According to the hazard quotient (HQ) of the TEs, the human health risk increased 2 to 3 times and was 3 to 4 times greater in lettuce than in radish. In contrast to the TEs, the occurrence of ABs and most of the ARGs was higher in radish roots than lettuce leaves. ABs were not detected in lettuce leaves, and the amount of all ARGs except blaTEM was 10 times lower than in radish roots. On the other hand, the addition of Zn and Cu had no significant effect on the occurrence of ABs and ARGs in the edible part of the vegetables, and no damage was found to plant productivity or physiology. The results show that the consumption of lettuce and radish grown in sewage-sludge-amended soils under our dosage does not pose an adverse human health effect, as the total HQ value was always less than 1, and the presence of ABs and ARGs was not found to have any potential impact. Nevertheless, further studies are needed to estimate the long-term effect on human health of crops grown under frequent application of biosolids in arable soil., The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry, and Competitiveness (MEIC) through Project AGL2017-89518-R. Rui You gratefully acknowledges a fellowship from the China Scholarship Council. The authors would further like to thank Mr. M. Massip for his kind assistance at the greenhouse facility.

Soil amendment with organic fertilizers is an effective approach to improve soil fertility. However, organic fertilizers may contain pollutants such as trace elements (TEs) and antibiotics (ABs), which, once deployed in arable soil, can be taken up by vegetables and have adverse effects on crops and human health. This study assesses the presence of 15 TEs and 16 ABs in lettuce grown in a greenhouse facility and amended with 3 different organic fertilizers (sewage sludge (SS), organic fraction of municipal solid waste (OFMSW), and swine manure (SM)) at 3 different fertilization doses. The results show that lettuces amended with SS resulted in the lowest content of TEs. Although 11 ABs were detected in the SM and SS fertilizers, only 3 ABs were detected in lettuce leaves. The concentrations of detected ABs in lettuce ranged from 0.67 ng/g fw (lincomycin) to 14.2 ng/g fw (ciprofloxacin) in SS. The organic fertilization dose did not affect the lettuce uptake of TEs or ABs. Moreover, the use of SS resulted in the highest lettuce yield of the organic amendments. The total hazard quotients (THQs) obtained for TEs and ABs were less than 1 for all the studied fertilization treatments. The highest THQs for TEs were observed in lettuce amended with SM (0.11–0.16), whereas the highest THQs for ABs were observed in SS treatments (0.06–0.09). The results thus suggest that consumption of lettuces amended with organic fertilizers would not pose a risk to human health due to the presence of studied TEs or ABs, but potentially harmful combined effects cannot ruled out., The authors gratefully acknowledge the financial support of the Spanish Ministry of Science and Competitiveness through Project AGL2017-89518-R. Rui You gratefully acknowledges the fellowship from the China Scholarship Council.

Antibiotics can be uptaken by plants from soil desorption or directly from irrigation water, but their metabolization pathways in plants are largely unknown. In this paper, an analytical workflow based on high-resolution mass spectrometry was applied for the systematic identification of biotransformation products of ofloxacin in lettuce. The targeted metabolites were selected by comparing the mass chromatograms of exposed with control samples using an advanced spectra-processing method (Fragment Ion Search). The innovative methodology presented allowed us to identify a total of 11 metabolites, including 5 ofloxacin metabolites that are being reported for the first time in plants. Accordingly, major transformation pathways were proposed revealing insight into how ofloxacin and related chemicals are metabolized in lettuce. Furthermore, the influence of biotransformation on potential residual antimicrobial activity of identified compounds was discussed. Human exposure to antibiotics at doses below the minimum inhibitory concentrations is crucial in human risk assessment, including food ingestion; however, in the case of ofloxacin presented results reveal that plant metabolites should also be considered so as not to underestimate their risk., The work presented in this paper is part of a project that has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 675530. Special thanks to Dr. Nikiforos Alygizakis and Dr. Josep Caixach, for their advice on the elucidation of metabolites.

The QuEChERS (quick, easy, cheap, effective, rugged, and safe) ultrasound-assisted method was successfully used to determine the presence of contaminants of emerging concern (CECs) in both the growing medium (i.e. soil) and vegetable samples (i.e. potato, onion, celery, parsnip and carrot) cultivated in household gardens under field conditions impacted by the application of livestock manure mixed with human waste. CECs with a broad range of physico-chemical properties including pharmaceuticals, plasticizers, herbicides, personal care products, and biocides were investigated. Among all studied CECs, diclofenac (DCL), carbamazepine, bisphenol A (BPA) and estrogenic hormones (estrone (E1), 17α-ethinyl estradiol (EE2)) were detected and quantified in vegetable samples with a concentration range from 0.114 to 13.3 ng/g fresh weight (f.w.), while BPA, E1, and EE2 were detected in soil samples with concentration ranges from 0.526 to 0.830 ng/g f.w., 0.121–0.199 ng/g f.w. and 0.118–0.333 ng/g f.w., respectively. DCL was only quantified above the limit of quantification in one soil sample (0.151 ng/g f.w.). The human health risk was estimated using the threshold of toxicological concern approach and a standard diet for two segments of the population (i.e. adult and child). The consumption of investigated vegetables contaminated with CECs poses no risk for the Serbian population., Parts of this investigation were obtained within the project nr. 172050 supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia and the Spanish Agency for Research (AEI) under the project nr AGL 2017-89518-R. The authors would also like to acknowledge the financial support provided by COST-European Cooperation in Science and Technology, to the COST Action ES1403: New and emerging challenges and opportunities in wastewater reuse (NEREUS).

Mediterranean rivers are severely affected by pollutants from industry, agriculture and urban activities. In this study, we examined how industrial pollutants, many of them known to act as endocrine disruptors (EDCs), could disturb the reproduction of the Catalan chub (Squalius laietanus). The survey was conducted throughout the reproductive period of S. laietanus (from March to July 2014) downstream an industrial WWTP located in the River Ripoll (NE Iberian Peninsula). Eighty fish (28 females and 52 males) were caught by electrofishing upstream and 77 fish (33 females and 44 males) downstream a WWTP. For both sexes, the gonadosomatic index (GSI) and gonadal histology were examined and related to water chemical analysis and fish biomarkers. Female fecundity was assessed using the gravimetric method. Fish from the polluted site showed enhanced biomarker responses involved in detoxification. Also, in the polluted site, lower GSI values were attained in both sexes and females displayed lower numbers of vitellogenic oocytes. Gonadal histology showed that all maturation stages of testicles and ovaries were present at the two study sites but fish males from the polluted site had smaller diameter seminiferous tubules. Water chemical analysis confirmed greater presence of EDCs in the river downstream the industrial WWTP. The chemicals benzotriazole and benzothiazole could be partially responsible for the observed alterations in the reproductive biology of S. laietanus., We thank J. Correas and E. Prats for their help at the microscopy laboratories of the University of Barcelona. Thanks also to J. D. Rodríguez-Teijeiro for the assistance and help in the field. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors are grateful to three anonymous reviewers and Víctor Bonet for the English review., With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

The developed method was evaluated for the determination of 10 antibiotics belonging to four chemical classes (fluoroquinolones, sulfonamides, lincosamides, and metoxybenzylpyrimidines) and six of their metabolites in four vegetable matrices (lettuce, tomato, cauliflower, and broad beans). The reported method detection limits were sufficiently low (0.1–5.8 ng/g dry weight) to detect target compounds in vegetables under real agricultural practices. Absolute and relative recovery values ranged from 40 to 118% and from 70 to 118%, respectively, for all targeted compounds at the spike level of 100 ng/g dry weight. Regarding method precision, the highest relative standard deviation (RSD) was obtained for enrofloxacin in lettuce (20%), while for the rest of the compounds in all matrices, the RSD values were below 20% for the same spike level. Matrix effects, due to electrospray ionization, ranged from − 26 to 29% for 85% of all estimated values. In a field study, four of the 10 targeted antibiotics were detected in tested vegetables. For the first time, antibiotic metabolites were quantified in vegetables grown under real field conditions. More specifically, decarboxyl ofloxacin and TMP304 were detected in tomato fruits (1.5 ng/g dry weight) and lettuce leaves (21.0–23.1 ng/g dry weight), respectively. It is important to remark that the concentration of TMP304 was five times higher than that from the parental compound, emphasizing the importance of metabolite analysis in monitoring studies. Therefore, the method provided a robust, reliable, and simple-to-use tool that could prove useful for routine multiclass analysis of antibiotics and their metabolites in vegetable samples. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature., The work presented in this paper is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 675530. The authors also gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry, and Competitiveness (MEIC) through Project AGL2014-59353-R. Funding This study was funded by H2020 MSCA grant agreement 675530 and the MEIC project nr. AGL2014-59353-R.

The discharge of emerging contaminants (ECs) from wastewater treatment plants into the aquatic environment is a matter of great importance due to the potential adverse effects that they can exert on aquatic biota. This study assesses the capacity of 12 full-scale horizontal-flow constructed wetlands (HFCWs) (18,000 m2 in total) used as tertiary treatment to remove 16 ECs from secondary treated wastewater (423,500 PE). Benzotriazole, 5-methylbenzotriazole, ketoprofen, and diclofenac were the most abundant (>2000 ng L−1 on average) in the secondary treated wastewater effluent. EC removal levels ranged from no removal to 92%, with an average removal of 43%. A significant relationship was observed between the removal of ECs in the HFCWs and their log Kow and molecular weight. The HFCWs were able to attenuate the predicted ecotoxicological effects of ECs on aquatic biota (Daphnia magna) by 66%. This study indicates that HFCWs are suitable for removing ECs from WWTP effluents and, therefore, reduce the ecotoxicological effects associated with pollutant discharges.

Although crop uptake of emerging organic contaminants (EOC) from irrigation water and soils has been previously reported, successful mitigation strategies have not yet been established. In this study, soil was amended with a wood-based biochar (BC) at two rates (0, 2.5 and 5% w/w) to evaluate the effect on mitigation of EOC uptake (i.e. bisphenol A, caffeine, carbamazepine, clofibric acid, furosemide, ibuprofen, methyl dihydrojasmonate, tris(2-chloroethyl)phosphate, triclosan, and tonalide) in lettuce (Lactuca sativa L.). After 28 days of irrigation with water containing EOCs at 15 µg L-1, the average EOC concentration in roots and leaves decreased by 20–76% in biochar amended soil relative to non BC-amended soil. In addition, the enantiomeric fractions (EF) of ibuprofen (IBU) in biochar amended soils (EF = 0.58) and unamended soils (EF = 0.76) suggest that the IBU sorbed fraction in BC is more recalcitrant to its biodegradation.

Social concern has raised during the last years due to the development of antibiotic resistance hotspots in different environmental compartments, including the edible parts of crops. To assess the influence of the water quality used for watering, we collected samples from soil, roots, leaves and beans from the legume plant Vicia faba (broad beans) in three agricultural peri-urban plots (Barcelona, NE Spain), irrigated with either groundwater, river water, or reclaimed water. Antibiotic resistance genes (ARGs) sul1, tetM, qnrS1, blaCTX-M-32, blaOXA-58, mecA, and blaTEM were quantified by real-time PCR, along with 16S rDNA and intl1 sequences, as proxies for bacterial abundance and integron prevalence, respectively. Microbiome composition of all samples were analyzed by high-throughput DNA sequencing. Results show a gradient of bacterial species diversity and of ARG prevalence from highly diverse soil samples to microbially-poor beans and leaves, in which Rhizobiales essentially displaced all other groups, and that presented very small loads of ARGs and integron sequences. The data suggest that the microbiome and the associated resistome were likely influenced by agricultural practices and water quality, and that future irrigation water legal standards should consider the specific Physiology of the different crop plants.

Recent studies have proven that vegetables cultivated in peri-urban areas are exposed to a greater concentration of organic microcontaminants (OMCs) and trace elements (TEs) than those grown in rural areas. In this study, the occurrence and human health risk of chemical contaminants (16 TEs and 33 OMCs) in edible parts of lettuce, tomato, cauliflower, and broad beans from two farm fields in the peri-urban area of the city of Barcelona and one rural site outside the peri-urban area were assessed. The concentration of TEs and OMCs (on fresh weight basis) ranged from non-detectable to 17.4 mg/kg and from non-detectable to 256 μg/kg, respectively. Tomato fruits showed the highest concentration of TEs and OMCs. Principal component analysis indicated that the occurrence of chemical contaminants in vegetables depended on the commodity rather than the location (peri-urban vs rural). Risk assessment using hazardous quotient (HQ) and threshold of toxicological concern (TTC) approaches showed that the risk for the consumption of target vegetables in the peri-urban area was low and similar to that observed for the rural site. Total HQ values for TEs were always below 1, and a minimum consumption of 150 g/day for children and 380 g/day for adults is required to reach the TTC due to the presence of pesticides. Further studies are needed to estimate the combined effect of TEs and OMCs on human health. © 2018 The Authors, The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) through Project AGL2014-59353-R . A. M. and Dr. V. M. would also like to acknowledge an FPI fellowship ( BES-2015-075745 ) and a Ramon y Cajal contract ( RYC-2013-12522 ) from the MEIC . The authors would further like to greatly thank the officers and farmers of the Baix Llobregat Agrarian Park for their assistance, as well as Ms. Yolanda Rodríguez, Ms. Marta Turull, Ms. Rui You, and Mr. Manel Martín for their technical assistance with the sampling and sample preparation. Appendix A

The reuse of treated wastewater (TWW) for irrigation and the use of biosolids and manures as soil amendment constitute significant pathways for the introduction of the contaminants of emerging concern (CECs) to the agricultural environment. Consequently, CECs are routinely detected in TWW-irrigated agricultural soils and runoff from such sites, in biosolids- and manure-amended soils, and in surface and groundwater systems and sediments receiving TWW. Crop plants grown in such contaminated agricultural environments have been found to uptake and accumulate CECs in their tissues, constituting possible vectors of introducing CECs into the food chain; an issue that is presently considered of high priority, thus needing intensive investigation. This review paper aims at highlighting the responsible mechanisms for the uptake of CECs by plants and the ability of each crop plant species to uptake and accumulate CECs in its edible tissues, thus providing tools for mitigating the introduction of these contaminants into the food chain. Both biotic (e.g. plants’ genotype and physiological state, soil fauna) and abiotic factors (e.g. soil pore water chemistry, physico-chemical properties of CECs, environmental perturbations) have been proven to influence the ability of crop plants to uptake and accumulate CECs. According to authors’ estimates, based on the thorough elaboration of knowledge produced by existing relevant studies, the ability of crop plants to uptake and accumulate CECs decrease in the order of leafy vegetables > root vegetables > cereals and fodder crops > fruit vegetables; though, the uptake of CECs by important crop plants, such as fruit trees, is not yet evaluated. Overall, further studies must be performed to estimate the potential of crop plants to uptake and accumulate CECs in their edible tissues, and to characterize the risk for human health represented by their presence in human and livestock food products. © 2018 Elsevier Inc., The authors would like to acknowledge the COST Action ES1403 NEREUS “New and emerging challenges and opportunities in wastewater reuse”, supported by COST (European Cooperation in Science and Technology), www.cost.eu.

Peri-urban horticulture performs environmental and socio-economic functions and provides ecological services to nearby urban areas. Nevertheless, industrialization and water pollution have led to an increase in the exposure of peri-urban vegetables to contaminants such as trace elements (TEs) and organic microcontaminants (OMCs). In this study, the occurrence of chemical contaminants (i.e., 16 TEs, 33 OMCs) in soil and lettuce leaves from 4 farm fields in the peri-urban area of the city of Barcelona was assessed. A rural site, outside the peri-urban area of influence, was selected for comparison. The concentration of TEs and OMCs ranged from non-detectable to 803 mg/kg dw and from non-detectable to 397 μg/kg dw respectively in the peri-urban soil, and from 6 · 10−5 to 4.91 mg/kg fw and from non-detectable to 193 μg/kg fw respectively in lettuce leaves. Although the concentration of Mo, Ni, Pb, and As in the soil of the peri-urban area exceeded the environmental quality guidelines, their occurrence in lettuce complied with human food standards (except for Pb). The many fungicides (carbendazim, dimetomorph, and methylparaben) and chemicals released by plastic pipelines (tris(1-chloro-2-propyl)phosphate, bisphenol F, and 2-mercaptobenzothiazole) used in agriculture were prevalent in the soil and the edible parts of the lettuce. The occurrence of these chemical pollutants in the peri-urban area did not affect the chlorophyll, lipid, or carbohydrate content of the lettuce leaves. PCA (Principal Component Analysis) showed that soil pollution, fungicide application, and irrigation water quality are the most relevant factors determining the presence of contaminants in crops.

Seven mesocosm-scale constructed wetlands (CWs) with different design configurations, dealing with primary-treated urban wastewater, were assessed for the concentration, distribution and fate of ten pharmaceutical and personal care products (PPCPs) [ibuprofen, ketoprofen, naproxen, diclofenac, salicylic acid, caffeine, carbamazepine, methyl dihydrojasmonate, galaxolide and tonalide] and eight of their transformation products (TPs). Apart from influent and effluent, various CW compartments were analysed, namely, substrate, plant roots and pore water. PPCP content in pore water depended on the specific CW configuration. Macrophytes can take up PPCPs through their roots. Ibuprofen, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide were present on the root surface with a predominance of galaxolide and caffeine in all the planted systems. Naproxen, ibuprofen, salicylic acid, methyl dihydrojasmonate, galaxolide and tonalide were uptaken by the roots. In order to better understand the removal processes, biomass measurement and biodegradability studies through the characterization of internal-external isomeric linear alkylbenzenes present on the gravel bed were performed. Three TPs namely, ibuprofen-amide, 3-ethylbenzophenone and 4-hydroxy-diclofenac were identified for the first time in wetland pore water and effluent water, which suggests de novo formation (they were not present in the influent). Conversely, O-desmethyl-naproxen was degraded through the wetland passage since it was detected in the influent but not in the subsequent treatment stages. Biodegradation pathways are therefore suggested for most of the studied PPCPs in the assessed CWs.

Aerated batch reactors (2.5 L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d-1 with the complete removal of N-NH4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10-1 Pa m3 mol-1 (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.

The distribution of aliphatic and aromatic hydrocarbons in surface sediments of the lower course of the Imo River (Nigeria) was investigated to determine the sources and fate of these compounds. The aliphatic fraction is characterized by a widespread contribution of highly weathered/biodegraded hydrocarbon residues (reflected in the absence of prominent n-alkane peaks coupled with the presence of 17α(H),21β(H)-25-norhopane, an indicator of heavy hydrocarbon biodegradation) of Nigerian crude oils (confirmed by the occurrence of 18α(H)-oleanane, a compound characteristic of oils of deltaic origin). The concentrations of polycyclic aromatic hydrocarbons (PAHs) ranging from 48 to 117 ng/g dry weight (dw; ∑13PAHs) indicate a moderate pollution, possibly lowered by the sandy lithology and low organic carbon (OC) content of the sediments. Concentrations slightly decrease towards the estuary of the river, probably due to the fact that these stations are affected by tidal flushing of pollutants adsorbed on sediment particles and carried away by occasional storm to the Atlantic Ocean. A number of PAH ratios, including parent/alkylated and isomeric compounds, indicates a predominance of petrogenic sources, with a low contribution of pyrolytic inputs, particularly of fossil fuel combustion. On the basis of OC/ON (>10) and Per/ΣPAHpenta- (>10) values, a diagenetic terrigenous OC was proposed as a source of perylene to the river.

The effect of hydraulic retention time (HRT) and seasonality on the removal efficiency of 26 organic microcontaminants from urban wastewater was studied in two pilot high-rate algal ponds (HRAPs). The targeted compounds included pharmaceuticals and personal care products, fire retardants, surfactants, anticorrosive agents, pesticides and plasticizers, among others. The pilot plant, which was fed at a surface loading rate of 7-29g of COD m-2d-1, consisted of a homogenisation tank and two parallel lines, each one with a primary settler and an HRAP with a surface area of 1.5m2 and a volume of 0.5m3. The two HRAPs were operated with different HRTs (4 and 8d). The removal efficiency ranged from negligible removal to more than 90% depending on the compound. Microcontaminant removal efficiencies were enhanced during the warm season, while the HRT effect on microcontaminant removal was only noticeable in the cold season. Our results suggest that biodegradation and photodegradation are the most important removal pathways, whereas volatilization and sorption were solely achieved for hydrophobic compounds (log Kow>4) with a moderately high Henry's law constant values (11-12Pam-3mol-1) such as musk fragrances. Whereas acetaminophen, ibuprofen and oxybenzone presented ecotoxicological hazard quotients (HQs) higher than 1 in the influent wastewater samples, the HQs for the effluent water samples were always below 1., Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona, 18-26, Barcelona, Spain GEMMA-Group of Environmental Engineering and Microbiology, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de Catalunya BarcelonaTech, c/Jordi Girona, 1-3, Building D1, Barcelona, Spain

Spain has one of the largest coastlines in Europe (ca. 8000 km), bearing heavy maritime traffic (more than 150,000 vessels/year), which carries a certain risk of oil pollution by accidents or operational activities. Oil pollution incidents may also occur during loading, unloading, and handling of oil products at the eight Spanish coastal refineries or in bunkering operations at Spanish ports. In addition to accidental discharges, most of the spills correspond to illegal releases of waste oils (bilge oils or sludges). The aerial surveillance of the Spanish waters (by aircraft and satellite) has detected, since 2010, almost one slick per day and at least one vessel is observed to be discharging “red-handed” every 100 flight hours. The implementation of a solid source identification system, based on the CEN methodology, just after the Prestige accident (2002), has strengthened the overall prevention of illegal or accidental pollution in Spanish waters. In this study, several case studies of spills in Spanish waters are described to illustrate the potential of the CEN methodology. Special emphasis is given to the assessment of weathering processes that should be taken into account for the correct interpretation of results.

Oil fingerprinting is widely used to defensibly determine the source of an oil spill by matching compositional parameters of both the spilled oil and candidate sources. The unambiguous identification of oil sources and their characteristics are of paramount importance for assessing the fate and environmental damage of the spill, provide an appropriate spill response and also for assigning responsibilities and liabilities. The most widely used methodologies in Europe and USA are, respectively, the CEN TR15522-2 and the ASTM5739-00 standard norms. Oil fingerprinting is currently based on profiling specific source biomarkers by GC–MS. However, new developments in gas chromatography and mass spectrometry (GC-MS/MS, GC × GC–FID–TOF, GC–IRMS) have allowed an enhanced sensitivity, selectivity, resolution and isotopic determination of oil biomarkers, providing additional tools for oil fingerprinting. Spectroscopic (fluorescence, FT-IR) and ultra-high resolution mass spectrometry methods (FT-ICRMS) have also shown a great potential in oil characterization. In this review, analytical, chemometric and remote sensing developments that have been used for fingerprinting and environmental fate studies of oil spills will be presented.

Water scarcity and water pollution have increased the pressure on water resources worldwide. This pressure is particularly important in highly populated areas where water demand exceeds the available natural resources. In this regard, water reuse has emerged as an excellent water source alternative for peri-urban agriculture. Nevertheless, it must cope with the occurrence of chemical contaminants, ranging from trace elements (TEs) to organic microcontaminants. In this study, chemical contaminants (i.e., 15 TEs, 34 contaminants of emerging concern (CECs)), bulk parameters, and nutrients from irrigation waters and crop productivity (Lycopersicon esculentum Mill. cv. Bodar and Lactuca sativa L. cv. Batavia) were seasonally surveyed in 4 farm plots in the peri-urban area of the city of Barcelona. A pristine site, where rain-groundwater is used for irrigation, was selected for background concentrations. The average concentration levels of TEs and CECs in the irrigation water impacted by treated wastewater (TWW) were 3 (35 ± 75 μg L− 1) and 13 (553 ± 1050 ng L− 1) times higher than at the pristine site respectively. Principal component analysis was used to classify the irrigation waters by chemical composition. To assess the impact of the occurrence of these contaminants on agriculture, a seed germination assay (Lactuca sativa L) and real field-scale study of crop productivity (i.e., lettuce and tomato) were used. Although irrigation waters from the peri-urban area exhibited a higher frequency of detection and concentration of the assessed chemical contaminants than those of the pristine site (P1), no significant differences were found in seed phytotoxicity or crop productivity. In fact, the crops impacted by TWW showed higher productivity than the other farm plots studied, which was associated with the higher nutrient availability for plants.

The occurrence of contaminants of emerging concern (CECs) in irrigation waters (up to low μg L-1) and irrigated crops (ng g-1 in dry weight) has been reported, but the linkage between plant morphological changes and plant metabolomic response has not yet been addressed. In this study, a non-targeted metabolomic analysis was performed on lettuce (Lactuca sativa L) exposed to 11 CECs (pharmaceuticals, personal care products, anticorrosive agents and surfactants) by irrigation. The plants were watered with different CEC concentrations (0-50 μg L-1) for 34 days under controlled conditions and then harvested, extracted, derivatised and analysed by comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometer (GC × GC-TOFMS). The resulting raw data were analysed using multivariate curve resolution (MCR) and partial least squares (PLS) methods. The metabolic response indicates that exposure to CECs at environmentally relevant concentrations (0.05 μg L-1) can cause significant metabolic alterations in plants (carbohydrate metabolism, the citric acid cycle, pentose phosphate pathway and glutathione pathway) linked to changes in morphological parameters (leaf height, stem width) and chlorophyll content. © 2017 The Author(s)., The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) under project AGL2014-59353-R. C. H. and Dr V. M. would like to acknowledge an FPI fellowship (BES-2012-055067) and a Ramon y Cajal contract (RYC-2013-12522) from the MEIC. The authors would also like to thank the Polytechnic University of Catalonia (UPC) for allowing them to use the Agropolis agriculture station. Dr H. P. would like to thank Sharif University of Technology (SUT) for financial support for a short sabbatical leave at IDAEA-CSIC.

Although there is a growing interest in emerging organic contaminants (EOCs), most research is focused on wastewater treatment, the occurrence of EOCs, and their fate in the aquatic environment. There is limited information about their behavior in agricultural soils, where they can be introduced via irrigation with treated wastewater (TWW). In this study, the degradation in an agricultural soil of eight EOCs (bisphenol A, carbamazepine, diethyl phthalate, ethyl paraben, 5-methyl-1H-benzotriazole, primidone, Surfynol 104, and tris(2-chloroethyl) phosphate) with a broad range of physical-chemical properties was monitored for 40 days. Two types of soil treatments were performed: non-sterilization and sterilization. In the non-sterilized soil, by the end of the incubation period, degradation was greater than 70% for all the target compounds except carbamazepine, Surfynol 104, and primidone ( 70%). These findings indicate that soil sterilization reduces overall degradation rates, which suggests that microbial activity plays an important role in the degradation of most of the EOCs studied in soil.

Determination of bioavailable concentrations of methylmercury (MeHg(+)) in freshwater is key to further understanding its potential risk and toxicity. In this work, two in-house-manufactured mercury-specific diffusive gradients in thin films (DGT) were used in laboratory to assess the lability of MeHg(+), and to develop a relationship between chemical lability and bioavailability. After diffusing through the diffusive gel, the MeHg(+) accumulated in a thiol functionalised resin gel was extracted using acidic thiourea that was analysed using aqueous-phase propylation followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography (GC) coupled to pyrolysis-atomic fluorescence spectrometry (Py-AFS) detection. The diffusion coefficient (D) at 25°C in agarose (A-DGT) in the absence and presence of dissolved organic matter (DOM) was obtained. Moreover, these values were experimentally compared against polyacrylamide (P-DGT), which is the most frequently used DGT for mercury to date. Statistically significant differences were observed between D values for A-DGT in the absence (3.15×10(-6) cm(2) s(-1)) and presence of DOM (2.68×10(-6) cm(2) s(-1)) and also for P-DGT (2.49×10(-6) and 1.69×10(-6) cm(2) s(-1)). Interestingly, our results show that diffusion of MeHg(+) was higher on agarose diffusive gel with and without DOM in comparison with those observed in polyacrylamide. Even with higher diffusion coefficients of MeHg(+) in the agarose diffusion layer, however, DGT based on polyacrylamide seems to be a better choice for eutrophic waters, when monitoring very low concentrations of MeHg(+), considering its slightly higher uptake capacity.

An analytical procedure for the determination of trihalomethanes (i.e., CHCl3, CHBrCl2, CHBr2Cl, and CHBr3) in leafy vegetable matrices was developed consisting of headspace solid-phase microextraction (HS-SPME) followed by GC-electron capture detector (ECD) determination. Factors affecting the extraction yield were optimized by multivariate methods in two steps. First, a 25-1 fractional factorial design was applied to screen for and assess the effects and interactions of sample mass (g), extraction temperature (°C), extraction time (min), the salting-out effect, and total volume (mL). Second, a response surface methodology design, i.e., central composite design, was applied to optimize the variables found to have a significant impact on the extraction process (extraction time, extraction temperature, and total sample volume), thereby making it possible to simulate the behavior of all the analytes except CHBr3. Finally, the multiple responses were simultaneously optimized using the desirability function. The optimum overall extraction conditions were achieved with an extraction time of 30 min, a temperature of 40 °C, and a total volume of 5 mL. These analytical conditions were validated by spiking plant samples at two concentration levels (2 and 5 mg kg−1), which yielded accurate and precise results for the target analytes. Detection and quantitation limits ranged from 0.09 to 0.64 μg kg−1 and 0.14 to 0.97 μg kg−1, respectively. Finally, chloroform and bromoform were detected in lettuce irrigated with a chlorinated secondary effluent at concentrations of 1.01 and 0.33 μg kg−1, respectively.

The aim of this study is to compare the removal of organic micropollutants (OMPs) in wastewater by activated sludge (AS) and constructed wetlands (CWs). This analysis was carried out in a wastewater treatment plant (WWTP) of a rural community where they implemented two technologies in parallel: AS and a pilot plant of horizontal subsurface flow (HSSF) constructed wetlands. In this case, these systems were fed by the same influent and the removal efficiencies of 14 OMPs, including analgesics/anti-inflammatories, anticonvulsants, stimulants, antifungals, fragrances, plasticizers, and transformation products, were evaluated in each system. Regarding the presence of OMPs in the wastewater, the concentrations of these compounds in the influent ranged from 0.16 to 7.75 &micro, g/L. In general, the removal efficiencies achieved by the AS system were between 10%&ndash, 95% higher than those values reported by HSSFs with values above 80% for naproxen, ibuprofen, diclofenac, caffeine, triclosan, methyl dihydrojasmonate, bisphenol-A, 2-hydroxyl ibuprofen, and carboxy ibuprofen (p &lt, 0.05). This behavior can be related to the aerobic conditions that promote the AS system with oxidation-reduction potential (ORP) and dissolved oxygen (DO) values above &minus, 281 mV and 0.24 mg/L, respectively. However, the removal of galaxolide was greater in HSSF system than in AS with significant difference of 70% (p &lt, 0.05). Despite these results, this study reveals that comparing both technologies, AS had the best removal performance of these OMPs studied.

Despite the social concern about the generalization of antibiotic resistance hotspots worldwide, very little is known about the contribution of different potential sources to the global risk. Here we present a quantitative analysis of the distribution of Antibiotic Resistance Genes (ARGs) in soil, rhizospheric soil, roots, leaves and beans in tomato, lettuce and broad beans crops (165 samples in total), grown in nine commercial plots distributed in four geographical zones in the vicinity of Barcelona (North East Spain). We also analyzed five soil samples from a nearby forest, with no record of agricultural activities. DNA samples were analyzed for their content in the ARGs sul1, tetM, qnrS1, blaCTX-M-32, blaOXA-58, mecA, and blaTEM, plus the integron intI1, using qPCR methods. In addition, soil microbiomes from the different plots were analyzed by amplicon-targeted 16S rRNA gene sequencing. Our data show a decreasing gradient of ARG loads from soil to fruits and beans, the latter showing only from 0.1 to 0.01% of the abundance values in soil. The type of crop was the main determinant for both ARG distribution and microbiome composition among the different plots, with minor contributions of geographic location and irrigation water source. We propose that soil amendment and/or fertilization, more than irrigation water, are the main drivers of ARG loads on the edible parts of the crop, and that they should therefore be specifically controlled. © 2019 Elsevier Inc., This work was supported by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 675530 . Additional Funding from the Spanish Ministerio de Economía y Competitividad ( Ministry of Economy and Competitiveness , project ISOMICS CTM2015-65691-R ) Disclaimer: The content of this article reflects only the authors' views and the E.U. Research Executive Agency is not responsible for any use that may be made of the information it contains.

Understanding weathering processes plays a critical role in oil spill forensics, which is based on the comparison of the distributions of selected compounds assumed to be recalcitrant and/or have consistent weathering transformations. Yet, these assumptions are based on limited laboratory and oil-spill studies. With access to additional sites that have been oiled by different types of oils and exposures, there is a great opportunity to expand on our knowledge about these transformations. Here, we demonstrate the effects of photooxidation on the overall composition of spilled oils caused by natural and simulated sunlight, and particularly on the often used polycyclic aromatic hydrocarbons (PAHs) and the biomarker triaromatic steranes (TAS). Both laboratory and field data from oil released from the Macondo well oil following the Deepwater Horizon disaster (2010), and heavy fuel-oil from the Prestige tanker spill (2002) have been obtained to improve the data interpretation of the typical fingerprinting methodology.

The capacity of a hybrid constructed wetland (CW) system consisting of two vertical flow (VF) CWs working alternatively (3 m(2)), one horizontal flow (HF) CW (2 m(2)) and one surface flow (FWS) CW (2 m(2)) in series to eliminate 13 emerging organic contaminants (EOCs) under three different hydraulic loading rates (HLRs) (0.06, 0.13 and 0.18 m d(-1) considering the area of the two VF beds) was studied through a continuous injection experiment General toxicity, dioxin-like activity, antimicrobial activity and estrogenicity were also measured under the highest hydraulic loading rate. The hybrid system was highly efficient on the removal of total injected EOCs (except for antibiotics, 43 +/- 32%) at all three HLRs (87 +/- 10%). The removal efficiency in the hybrid CW system showed to decrease as the HLR increased for most compounds. The VF wetlands removed most of the injected EOCs more efficiently than the other two CWs, which was attributable to the predominant aerobic degradation pathways of the VF beds (70 +/- 21%). General toxicity was reduced up to 90% by the VF beds. Estrogenicity and dioxin-like activity were similarly reduced by the VF and the HF wetlands, whereas antimicrobial activity was mainly removed by the FWS wetland. Bearing this in mind, this injection study has demonstrated that the use of hybrid CW systems is a suitable wastewater technology for removing EOCs and toxicity even at high HLRs. (C) 2013 Elsevier B.V. All rights reserved.

Two different nonthermal plasma reactors at atmospheric pressure were assessed for the removal of organic micropollutants (atrazine, chlorfenvinfos, 2,4-dibromophenol, and lindane) from aqueous solutions (1-5 mg L(-1)) at laboratory scale. Both devices were dielectric barrier discharge (DBD) reactors; one was a conventional batch reactor (R1) and the other a coaxial thin-falling-water-film reactor (R2). A first-order degradation kinetics was proposed for both experiments. The kinetic constants (k) were slightly faster in R1 (0.534 min(-1) for atrazine; 0.567 min(-1) for chlorfenvinfos; 0.802 min(-1) for 2,4-dibromophenol; 0.389 min(-1) for lindane) than in R2 (0.104 min(-1) for atrazine; 0.523 min(-1) for chlorfenvinfos; 0.273 min(-1) for 2,4-dibromophenol; 0.294 min(-1) for lindane). However, energy efficiencies were about one order of magnitude higher in R2 (89 mg kW(-1) h(-1) for atrazine; 447 mg kW(-1) h(-1) for c hlorfenvinfos; 47 mg kW(-1) h(-1) for 2,4-dibromophenol; 50 mg kW(-1) h(-1) for lindane) than in R1. Degradation by -products of all four compounds were identified in R1. As expected, when the plasma treatment (R1) was applied to industrial wastewater spiked with atrazine or lindane, micropollutant removal was also achieved, although at a lower rate than with aqueous solutions (k = 0.117 min(-1) for atrazine; k = 0.061 min(-1) for lindane).

Multivariate curve resolution-alternating least squares (MCR-ALS) analysis is proposed to solve chromatographic challenges during two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) analysis of complex samples, such as crude oil extract. In view of the fact that the MCR-ALS method is based on the fulfillment of the bilinear model assumption, three-way and four-way GC × GC-TOFMS data are preferably arranged in a column-wise superaugmented data matrix in which mass-to-charge ratios (m/z) are in its columns and the elution times in the second and first chromatographic columns are in its rows. Since m/z values are common for all measured spectra in all second-column modulations, unavoidable chromatographic challenges such as retention time shifts within and between GC × GC-TOFMS experiments are properly handled. In addition, baseline/background contributions can be modeled by adding extra components to the MCR-ALS model. Another outstanding aspect of MCR-ALS analysis is its extreme flexibility to consider all samples (standards, unknowns, and replicates) in a single superaugmented data matrix, allowing joint analysis. In this way, resolution, identification, and quantification results can be simultaneously obtained in a very fast and reliable way. The potential of MCR-ALS analysis is demonstrated in GC × GC-TOFMS analysis of a North Sea crude oil extract sample with relative errors in estimated concentrations of target compounds below 6.0 % and relative standard deviations lower than 7.0 %. The results obtained, along with reasonable values for the lack of fit of the MCR-ALS model and high values of the reversed match factor in mass spectra similarity searches, confirm the reliability of the proposed strategy for GC × GC-TOFMS data analysis.

We report experimentally determined first-order rate constants of MeHg photolysis in three waters along a Boreal lake-wetland gradient covering a range of pH (3.8-6.6), concentrations of total organic carbon (TOC 17.5-81 mg L(-1)), total Fe (0.8-2.1 mg L(-1)), specific UV254 nm absorption (3.3-4.2 L mg(-1) m(-1)) and TOC/TON ratios (24-67 g g(-1)). Rate constants determined as a function of incident sunlight (measured as cumulative photon flux of photosynthetically active radiation, PAR) decreased in the order dystrophic lakedystrophic lake/wetlandriparian wetland. After correction for light attenuation by dissolved natural organic matter (DOM), wavelength-specific (PAR: 400-700 nm, UVA: 320-400 nm and UVB: 280-320 nm) first-order photodegradation rate constants (kpd) determined at the three sites were indistinguishable, with average values (± SE) of 0.0023 ± 0.0002, 0.10 ± 0.024 and 7.2 ± 1.3 m(2) E(-1) for kpdPAR, kpdUVA, and kpdUVB, respectively. The relative ratio of kpdPAR, kpdUVA, and kpdUVB was 1:43:3100. Experiments conducted at varying MeHg/TOC ratios confirm previous suggestions that complex formation with organic thiol groups enhances the rate of MeHg photodegradation, as compared to when O and N functional groups are involved in the speciation of MeHg. We suggest that if the photon fluxes of PAR, UVA, and UVB radiation are separately determined and the wavelength-specific light attenuation is corrected for, the first-order rate constants kpdPAR, kpdUVA, and kpdUVB will be universal to waters in which DOM (possibly in concert with Fe) controls the formation of ROS, and the chemical speciation of MeHg is controlled by the complexation with DOM associated thiols.

The Biobío River basin is highly impacted by a variety of anthropogenic activities such as pulp mills and urban wastewaters subjected to different treatment processes. This work assesses for the first time, the contamination source and biological effects (estrogenic and dioxin-like activities) in the river basin by the determination of 45 organic microcontaminants in seven sediment samples. Pressurized solvent extraction combined with two-dimensional comprehensive gas chromatography coupled to time of flight mass spectrometry was employed for this purpose. The organic microcontaminants identified comprise monoterpenes, sesquiterpenes, diterpenes, ionones, lineal alkyl benzenes, polycyclic aromatic hydrocarbons, musk fragrances, sterols and phathalate esters. The presence of pine and eucalyptus pulp mill effluents increased the abundance of resin-derived neutral compounds and monoterpenes respectively. A principal component analysis showed that the Biobío River basin was impacted by domestic wastewater treatment plants (WWTPs), pine or eucalyptus Kraft pulp mills and pyrolytic and pyrogenic processes. Finally, the recombinant yeast assays showed that the presence of estrogenic and dioxin-like activity was mostly located in sediments impacted by domestic WWTP effluents.

Benzothiazoles (BTHs) and benzotriazoles (BTRs) belong to a high production volume chemicals widely used in both industrial and household applications. Since they are recalcitrant to biodegradation, they are widespread in the environment. However, the BTHs and BTRs determination in environmental matrices is hindered by the coelution with coextracted organic matter and the poor selectivity in mass spectrometry due to the low mass of their diagnostic ions. Accordingly, this study examines the selectivity and suitability of new commercially available ionic liquid (IL) stationary phases for GC–MS and their application to the determination of BTHs and BTRs in wastewater samples. Five different IL columns were tested and the best results in terms of resolution, peak symmetry and analysis time were obtained with the SLB-IL59.

Although a myriad of organic microcontaminants may occur in irrigation waters, little attention has been paid to their incorporation in crops. In this work, a systematic approach to assess the final fate of both ionizable and neutral organic contaminants taken up by plants is described. In vitro uptake of triclosan (TCS), hydrocinnamic acid (HCA), tonalide (TON), ibuprofen (IBF), naproxen (NPX), and clofibric acid (CFA) were studied in lettuce ( Lactuca sativa L) and spath ( Spathiphyllum spp.) as model plants. After 30 days incubation, analyte depletion from the culture medium was 85-99% (lettuce) and 51-81% (spath). HCA, NPX, and CFA exhibited the highest depletion rate in both plant species. Lettuce plant tissue analysis revealed an accumulation of all compounds except for HCA. These compounds reached a peak in tissue concentration followed by a sudden drop, probably due to the plant detoxification system and analyte depletion from the culture medium. Kinetic characterization of the uptake and detoxification processes was fitted to a pseudo-first-order rate. Compounds with a carboxylic group in their structure exhibited higher uptake rates, possibly due to the contribution of an ion trap effect. Molecular weight and log K(ow) played a direct role in uptake in lettuce, as proven by the significant correlation of both properties to depletion and by the correlation of molecular weight to kinetic uptake rates.

Emerging contaminants have received much attention in recent years due to their presence in surface waters, but little attention has been paid to their occurrence in agricultural irrigation waters. This study investigated the occurrence of these compounds in an agricultural irrigation network in northeastern Spain and, for the first time, using two plant uptake models, estimated the concentration of selected micropollutants in crops. The concentration of micropollutants in agricultural irrigation waters ranged from 10 to 5130 ng L(-1) and exhibited some attenuation over the course of the irrigation network. Bromoform, chloroform, diclofenac, caffeine, ibuprofen, naproxen, methyl dihydrojasmonate, galaxolide, butylated hydroxytoluene, and butylated hydroxyanisole were the most abundant contaminants (200 ng L(-1), on average). The estimated concentration of micropollutants in crops ranged from1 to 7677 ng kg(-1), with the neutral compounds being the most abundant. Moreover, the predicted data obtained by fate models generally agreed with experimental data. Finally, human exposure to micropollutants through fruit and vegetable consumption was estimated to be 9.8 μg per person and week (Σ 27 contaminants detected). Further studies are needed to determine the health implications that the presence of these compounds in fruit and vegetables may have for consumers.

The low Ebro River basin (NE Spain) represents a particular case of chronic and long-term mercury pollution due to the presence of an industrial waste (up to 436 μg/g of Hg) coming from a chlor-alkali plant Albeit high total mercury (THg) levels have been previously described in several aquatic species from the surveyed area, methylmercury (MeHg) values in fish individuals have never been reported. Accordingly, in order to investigate bioaccumulation patterns at different levels of the aquatic food web of such polluted area, crayfish and various fish species, were analysed for THg and MeHg content. At the hot spot, THg mean values of crayfish muscle tissue and hepatopancreas were 10 and 15 times, respectively, greater than the local background level. Higher mean THg concentrations were detected in piscivorous (THg=0.848±0.476 μg/g wet weight (ww); MeHg=0.672±0.364 μg/g ww) than in non-piscivorous fish (THg=0.305±0.163 μg/g ww; MeHg=0.278±0.239 μg/g ww). Although these results indicated that THg in fish increased significantly with increasing trophic position, the percentage of the methylated form of Hg was not strongly influenced by differences in relative trophic position. This is an important finding, since the fraction of THg as MeHg in the top fish predator was unexpectedly lower than for other species of the aquatic food chain. Moreover, mean THg concentrations in piscivorous fish exceed the maximum level recommended for human consumption.From our findings, it is clear that for this specific polluted system, speciation becomes almost mandatory when risk assessment is based on MeHg, since single measurements of THg are inadequate and could lead to an over- or under-estimation of contamination levels. Keywords: Mercury, Methylmercury, Bioavailability, Trophic dynamics, Ebro River