Fungal degradation of selected medium to highly polar pesticides by Trametes versicolor: kinetics, biodegradation pathways, and ecotoxicity of treated waters.

The massive use of pesticides represents one of the main causes of environmental deterioration, as they have adverse effects on non-target organisms. Thus, the development of technologies capable of reducing their release into the environment is urgently needed. This study reports for the first time the white-rot fungus Trametes versicolor as an alternative towards the degradation of medium to highly polar pesticides such as the organophosphate malathion, and the neonicotinoids acetamiprid and imidacloprid. Specifically, T. versicolor could completely remove 1 mg/L of malathion in an Erlenmeyer flask within 48 h, while experiments of acetamiprid and imidacloprid (4 mg/L), conducted in air-pulse fluidized bioreactors, resulted in degradation percentages of 20% and 64.7%, respectively, after 7 days of operation. Enzymatic exploration studies revealed that the cytochrome P450 system, instead of the extracellular enzyme laccase, is involved in the degradation of acetamiprid and imidacloprid. The degradation pathways were proposed based on the main transformation products (TPs) formed in the solutions: seven in the case of malathion, and two and one in the case of imidacloprid and acetamiprid, respectively. Although the TPs identified were predicted to be less toxic than the investigated pesticides, the toxicity of the individual solutions slightly increased throughout the degradation process, according to the Microtox assay. However, the solution toxicity was always below the threshold established in the local regulation. Although additional research is needed to implement this treatment at a pilot plant scale, this work highlights the potential of T. versicolor to bio-remediate pesticide-contaminated waters.

Analysis and fate of 14 relevant wastewater-derived organic pollutants in long-term exposed soil.

The growing use of reclaimed water in agriculture worldwide calls for developing high-sensitivity methods to quantify wastewater-derived organic contaminants in soils so that the potential risk of this irrigation practice can be properly assessed. This work describes an analytical method for the determination of trace levels of 14 drugs that are known to be poorly removed during conventional wastewater treatment in soil. The analytes selected for investigation included ten pharmaceuticals from different therapeutic classes (carbamazepine, diclofenac, cis-diltiazem, lamotrigine, methadone, midazolam, oxcarbazepine, sulfamethoxazole, trimethoprim, valsartan), one illicit drug (cocaine), and three transformation products/metabolites (acridone, 4'-hydroxydiclofenac, and valsartan acid), thereby covering a broad range of physical-chemical properties. The methodology developed was based on ultrasonic solvent extraction (USE) of the analytes from the soil matrix, and subsequent clean-up and analysis of the USE extracts with a fully automated approach by means of solid-phase extraction and liquid chromatography-tandem mass spectrometry detection (online SPE-LC-MS/MS). The method was fully validated with affording method detection and quantification limits ranging from 0.03 to 1 ng g-1 and from 0.09 to 3.3 ng g-1, respectively. This method was applied to investigate the fate of the selected drugs in potting soil irrigated for a long term (60 days) either with water containing the target compounds at a concentration of 200 µg L-1 or with wastewater treatment plant effluent and thus, at real environmental concentrations. All investigated compounds were found to accumulate in soil irrigated with artificially fortified water. The highest accumulation potential was observed for cis-diltiazem followed by methadone and midazolam that presented average concentrations of 1517 ng g-1, 1041 ng g-1, and 962 ng g-1 d.w., respectively. On the contrary, oxcarbazepine (5.8 ng g-1) and sulfamethoxazole (22 ng g-1) were the target drugs presenting the lowest accumulation potential. Only trace levels of ten drugs were measured in soil irrigated with regenerated water (average concentrations between 1.6 and 4.7 ng g-1 d.w.). Graphical abstract.

A reliable LC-MS/MS-based method for trace level determination of 50 medium to highly polar pesticide residues in sediments and ecological risk assessment.

The occurrence of polar pesticides in sediments has not been extensively investigated because of their relatively poor hydrophobicity and apparently less persistence in the environment. However, their continuous release into the aquatic systems calls for the evaluation of their potential accumulation in sediments and the role of this matrix as a potential source of these compounds. Considering this, a method based on pressurized liquid extraction (PLE), extract clean-up by solid phase extraction (SPE), and analyte determination by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated to analyze 50 relevant (frequently used and/or regulated or found in water) medium to highly polar pesticides in sediments. The method showed good performance regarding accuracy (relative recoveries between 76 and 124%), precision (relative standard deviation values < 20%), sensitivity (LODs in the low nanogram per gram for most compounds), linearity (coefficients of determination > 0.99), and matrix effects (negligible for all analytes). The use of an isotope dilution approach for quantification ensures result reliability. As a part of the validation process, the method was applied to the analysis of the target pesticides in sediments from the Llobregat River (NE Spain) showing the presence of five of them, namely, terbutryn, dichlorvos, terbuthylazine, diazinon, and irgarol. All 5 pesticides, due to both the concentrations found and their physical-chemical characteristics, demonstrate high potential for bioaccumulation and risk to aquatic organisms. Additional multi-disciplinary studies that investigate pesticide occurrence in different aquatic compartments and evaluate the potential risks for aquatic ecosystems are required to assess the environmental impact and significance of the presence of pesticides in sediments. Graphical Abstract.

Chlorination of Source Water Containing Iodinated X-ray Contrast Media: Mutagenicity and Identification of New Iodinated Disinfection Byproducts.

Iodinated contrast media (ICM) are nonmutagenic agents administered for X-ray imaging of soft tissues. ICM can reach µg/L levels in surface waters because they are administered in high doses, excreted largely unmetabolized, and poorly removed by wastewater treatment. Iodinated disinfection byproducts (I-DBPs) are highly genotoxic and have been reported in disinfected waters containing ICM. We assessed the mutagenicity in Salmonella of extracts of chlorinated source water containing one of four ICM (iopamidol, iopromide, iohexol, and diatrizoate). We quantified 21 regulated and nonregulated DBPs and 11 target I-DBPs and conducted a nontarget, comprehensive broad-screen identification of I-DBPs. We detected one new iodomethane (trichloroiodomethane), three new iodoacids (dichloroiodoacetic acid, chlorodiiodoacetic acid, bromochloroiodoacetic acid), and two new nitrogenous I-DBPs (iodoacetonitrile and chloroiodoacetonitrile). Their formation depended on the presence of iopamidol as the iodine source; identities were confirmed with authentic standards when available. This is the first identification in simulated drinking water of chloroiodoacetonitrile and iodoacetonitrile, the latter of which is highly cytotoxic and genotoxic in mammalian cells. Iopamidol (5 µM) altered the concentrations and relative distribution of several DBP classes, increasing total haloacetonitriles by >10-fold. Chlorination of ICM-containing source water increased I-DBP concentrations but not mutagenicity, indicating that such I-DBPs were either not mutagenic or at concentrations too low to affect mutagenicity.

Development and validation of an analytical method based on liquid chromatography-tandem mass spectrometry detection for the simultaneous determination of 13 relevant wastewater-derived contaminants in lettuce.

We present an analytical method developed and validated to study the potential uptake of 13 selected drugs (ten pharmaceuticals, one illicit drug, and two transformation products) into lettuce plants from contaminated water and soil. Some of the selected drugs (i.e., cocaine, methadone, cis-diltiazem, valsartan, and valsartan acid), which are commonly present in treated wastewater, were investigated for the first time in plant tissues. The method is based on ultrasonic solvent extraction with acetonitrile-methanol (1:1, v/v) and subsequent automated extract cleanup and analysis by means of online solid-phase extraction-liquid chromatography-tandem mass spectrometry. Optimum extraction conditions were selected after evaluation of analyte recoveries with four different extraction techniques (ultrasonic solvent extraction, solid-liquid extraction, pressurized liquid extraction, and a "quick, easy, cheap, effective, rugged, and safe" based method) and six different solvent mixtures. Furthermore, two different solid-phase extraction cleanup sorbents were evaluated. The method developed has high sensitivity (with limits of detection between 0.1 and 12.6 ng per gram dry weight and limits of quantification between 0.5 and 42.0 ng per gram dry weight), satisfactory accuracy (with analyte relative recoveries above 80% for all analytes but acridone and oxcarbazepine), and good repeatability (with relative standard deviations below 9% for all analytes). As part of the validation procedure, the analytical method was applied to the analysis of lettuce plants irrigated with water fortified with the selected compounds for the entire growing period. The results obtained evidenced the transfer of all the investigated drugs into lettuce leaves. Graphical Abstract ᅟ.

Formation of iodo-trihalomethanes, iodo-haloacetic acids, and haloacetaldehydes during chlorination and chloramination of iodine containing waters in laboratory controlled reactions.

Iodine containing disinfection by-products (I-DBPs) and haloacetaldehydes (HALs) are emerging disinfection by-product (DBP) classes of concern. The former due to its increased potential toxicity and the latter because it was found to be the third most relevant DBP class in mass in a U.S. nationwide drinking water study. These DBP classes have been scarcely investigated, and this work was performed to further explore their formation in drinking water under chlorination and chloramination scenarios. In order to do this, iodo-trihalomethanes (I-THMs), iodo-haloacetic acids (I-HAAs) and selected HALs (mono-HALs and di-HALs species, including iodoacetaldehyde) were investigated in DBP mixtures generated after chlorination and chloramination of different water matrices containing different levels of bromide and iodide in laboratory controlled reactions. Results confirmed the enhancement of I-DBP formation in the presence of monochloramine. While I-THMs and I-HAAs contributed almost equally to total I-DBP concentrations in chlorinated water, I-THMs contributed the most to total I-DBP levels in the case of chloraminated water. The most abundant and common I-THM species generated were bromochloroiodomethane, dichloroiodomethane, and chlorodiiodomethane. Iodoacetic acid and chloroiodoacetic acid contributed the most to the total I-HAA concentrations measured in the investigated disinfected water. As for the studied HALs, dihalogenated species were the compounds that predominantly formed under both investigated treatments.

Characterization of iodinated disinfection by-products in chlorinated and chloraminated waters using Orbitrap based gas chromatography-mass spectrometry.

Recent developments in gas chromatography (GC)-mass spectrometry (MS) have opened up the possibility to use the high resolution-accurate mass (HRAM) Orbitrap mass analyzer to further characterize the volatile and semivolatile fractions of environmental samples. This work describes the utilization of GC Orbitrap MS technology to characterize iodine-containing disinfection by-products (iodo-DBPs) in chlorinated and chloraminated DBP mixture concentrates. These DBP mixtures were generated in lab-scale disinfection reactions using Llobregat river water and solutions containing Nordic Lake natural organic matter (NOM). The DBPs generated were concentrated using XAD resins, and extracts obtained were analyzed in full scan mode with the GC Orbitrap MS. Integration of high resolution accurate mass information and fragment rationalization allowed the characterization of up to 11 different iodo-DBPs in the water extracts analyzed, including one new iodo-DBP reported for the first time. Overall, formation of iodo-DBPs was enhanced during chloramination reactions. As expected, NOM characteristics and iodide and bromide content of the tested waters affected the amount and type of iodo-DBPs generated.

Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water.

The introduction of drinking water disinfection greatly reduced waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water leads to an unintended consequence, the formation of drinking water disinfection byproducts (DBPs). The haloacetaldehydes (HALs) are the third largest group by weight of identified DBPs in drinking water. The primary objective of this study was to analyze the occurrence and comparative toxicity of the emerging HAL DBPs. A new HAL DBP, iodoacetaldehyde (IAL) was identified. This study provided the first systematic, quantitative comparison of HAL toxicity in Chinese hamster ovary cells. The rank order of HAL cytotoxicity is tribromoacetaldehyde (TBAL) ≈ chloroacetaldehyde (CAL) > dibromoacetaldehyde (DBAL) ≈ bromochloroacetaldehyde (BCAL) ≈ dibromochloroacetaldehyde (DBCAL) > IAL > bromoacetaldehyde (BAL) ≈ bromodichloroacetaldehyde (BDCAL) > dichloroacetaldehyde (DCAL) > trichloroacetaldehyde (TCAL). The HALs were highly cytotoxic compared to other DBP chemical classes. The rank order of HAL genotoxicity is DBAL > CAL ≈ DBCAL > TBAL ≈ BAL > BDCAL>BCAL ≈ DCAL>IAL. TCAL was not genotoxic. Because of their toxicity and abundance, further research is needed to investigate their mode of action to protect the public health and the environment.

Toxicity and underlying lipidomic alterations generated by a mixture of water disinfection byproducts in human lung cells.

Complex mixtures of disinfection by-products (DBPs) are present in disinfected waters, but their mixture toxicity has been rarely described. Apart from ingestion, DBP exposure can occur through inhalation, which may lead to respiratory effects in highly exposed individuals. However, the underlying biological mechanisms have yet to be elucidated. This study aimed to investigate the toxicity of a mixture of 10 DBPs, including haloacetic acids and haloaromatics, on human alveolar A549 cells by assessing their cytotoxicity, genotoxicity, and impact on the cell lipidome. A DBP mixture up to 50 µM slightly reduced cell viability, induced the generation of reactive oxygen species (ROS) up to 3.5-fold, and increased the frequency of micronuclei formation. Exposure to 50 µM DBP mixture led to a significant accumulation of triacylglycerides and a decrease of diacylglycerides and phosphatidylcholines in A549 cells. Lipidomic profiling of extracellular vesicles (EVs) released in the culture medium revealed a marked increase in cholesterol esters, sphingomyelins, and other membrane lipids. Overall, these alterations in the lipidome of cells and EVs may indicate a disruption of lipid homeostasis, and thus, potentially contribute to the respiratory effects associated with DBP exposure.

Non-regulated haloaromatic water disinfection byproducts act as endocrine and lipid disrupters in human placental cells.

The disinfection of drinking water generates hundreds of disinfection byproducts (DBPs), including haloaromatic DBPs. These haloaromatic DBPs are suspected to be more toxic than haloaliphatic ones, and they are currently not regulated. This work investigates their toxicity and ability to interfere with estrogen synthesis in human placental JEG-3 cells, and their genotoxic potential in human alveolar A549 cells. Among the haloaromatic DBPs studied, halobenzoquinones (2,6-dichloro-1,4-benzoquinone (DCBQ) and 2,6-dibromo-1,4-benzoquinone (DBBQ)) showed the highest cytotoxicity (EC50: 18-26 µg/mL). They induced the generation of very high levels of reactive oxygen species (ROS) and up-regulated the expression of genes involved in estrogen synthesis (cyp19a1, hsd17b1). Increased ROS was linked to significant depletion of polyunsaturated lipid species from inner cell membranes. The other DBPs tested showed low or no significant cytotoxicity (EC50 ≥ 100 µg/mL), while 2,4,6-trichloro-phenol (TCP), 2,4,6-tribromo-phenol (TBP) and 3,5-dibromo-4-hydroxybenzaldehyde (DCHB) induced the formation of micronuclei at concentrations much higher than those typically found in water (100 µg/mL). This study reveals the different modes of action of haloaromatic DBPs, and highlights the toxic potential of halobenzoquinones, which had a significant impact on the expression of placenta steroid metabolism related genes and induce oxidative stress, implying potential adverse health effects.

Development of QuEChERS-based multiresidue analytical methods to determine pesticides in corn, grapes and alfalfa.

Analytical methods based on QuEChERS and liquid chromatography-tandem mass spectrometry were developed for the determination of 42 polar and semi-polar pesticides in three representative vegetable matrices, viz. corn, grapes and alfalfa. A 26-2 fractional factorial experimental design was used to cost-effectively optimize the extraction procedure. The optimal analytical approaches were validated in terms of linearity, sensitivity, trueness, and precision. Most of the target pesticides showed a relative recovery of 70-120 %. Moreover, limits of detection (between 0.01 ng/g and 20 ng/g) were below the maximum residue levels set for the target analytes in nearly all cases. Analysis of real samples showed the presence of five pesticides in grapes and alfalfa at concentrations between the method LOQs and 40 ng/g. To the authors' knowledge, these methods are the first ever described for the determination of 6, 13 and 24 of the 42 target pesticides measured in corn, grapes and alfalfa, respectively.

Prioritization of organic contaminants in a reclaimed water irrigation system using wide-scope LC-HRMS screening.

A prioritization procedure was developed and implemented at the local level to identify the most relevant organic contaminants of emerging concern (CECs) in an agricultural area irrigated with reclaimed water. A wide-scope screening methodology based on UPLC-HRMS analysis was applied to holistically characterize the CEC footprint in water and its spatial and temporal variations. One hundred and fifty-eight CECs, including pharmaceuticals, industrial chemicals, and pesticides, among others, were identified with a confidence level of 2 in the water samples investigated. After water treatment in the reclamation plant and transport within the irrigation channel network, more than a hundred compounds were still detected at the location where water is abstracted for crop irrigation. Compound ecotoxicity and occurrence (semi-quantified concentrations or peak intensity) were the parameters used to prioritize CECs in the water used for irrigation. Results pointed at venlafaxine, O-desmethyl-venlafaxine, galaxolidone, theophylline/paraxanthine, oxybenzone, and N-phenyl-1-naphtylamine, among others, as CECs of concern in the investigated area. This study provides a simple and cost-effective approach to detecting site-specific priority pollutants that could otherwise be overlooked by national or European regulations. The prioritization tool provided contributes to rationally designing monitoring and attenuation programs and efficiently managing water resources, by ensuring the safety of reclaimed water applications.

Genotoxicity and endocrine disruption potential of haloacetic acids in human placental and lung cells.

Chlorination of water results in the formation of haloacetic acids (HAAs) as major disinfection byproducts (DBPs). Previous studies have reported some HAAs species to act as cytotoxic, genotoxic, and carcinogenic. This work aimed at further exploring the toxicity potential of the most investigated HAAs (chloroacetic (CAA), bromoacetic (BAA), iodoacetic (IAA) acid) and HAAs species with high content of bromine (tribromoacetic acid (TBAA)), and iodine in their structures (chloroiodoacetic (CIAA) and diiodoacetic acid (DIAA)) to human cells. Novel knowledge was generated regarding cytotoxicity, oxidative stress, endocrine disrupting potential, and genotoxicity of these HAAs by using human placental and lung cells as in vitro models, not previously used for DBP assessment. IAA showed the highest cytotoxicity (EC50: 7.5 µM) and ability to generate ROS (up to 3-fold) in placental cells, followed by BAA (EC50: 20-25 µM and 2.1-fold). TBAA, CAA, DIAA, and CIAA showed no significant cytotoxicity (EC50 > 250 µM). All tested HAAs decreased the expression of the steroidogenic gene hsd17b1 up to 40 % in placental cells, and IAA and BAA (0.01-1 µM) slightly inhibited the aromatase activity. HAAs also induced the formation of micronuclei in A549 lung cells after 48 h of exposure. IAA and BAA showed a non-significant increase in micronuclei formation at low concentrations (1 µM), while BAA, CAA, CIAA and TBAA were genotoxic at exposure concentrations above 10 µM (100 µM in the case of DIAA). These results point to genotoxic and endocrine disruption effects associated with HAA exposure at low concentrations (0.01-1 µM), and the usefulness of the selected bioassays to provide fast and sensitive responses to HAA exposure, particularly in terms of genotoxicity and endocrine disruption effects. Further studies are needed to define thresholds that better protect public health.

Human footprint on the water quality from the northern Antarctic Peninsula region.

This study assessed the human footprint on the chemical pollution of Antarctic waters by characterizing inorganic chemicals and selected organic anthropogenic contaminants of emerging concern (CECs) in inland freshwater and coastal seawater and the associated ecotoxicological risk. Nicotine and tolytriazole, present in 74% and 89% of the samples analyzed, respectively, were the most ubiquitous CECs in the investigated area. The most abundant CECs were citalopram, clarithromycin, and nicotine with concentrations reaching 292, 173, and 146 ng/L, respectively. The spatial distribution of CECs was not linked to any water characteristic or inorganic component. The contamination pattern by CECs in inland freshwater varied among locations, whereas it was very similar in coastal seawater. This suggests that concentrations in inland freshwater may be ruled by environmental processes (reemission from ice, atmospheric deposition, limited photo- and biodegradation processes, etc.) in addition to human activities. Following risk assessment, citalopram, clarithromycin, nicotine, venlafaxine, and hydrochlorothiazide should be considered of concern in this area, and hence, included in future monitoring of Antarctic waters and biota. This work provides evidence on the fact that current measures taken to protect the pristine environment of Antarctica from human activities are not effective to avoid CEC spread in its aquatic environment.

High-throughput analysis of the steroid profile in placental cell cultures to evaluate endocrine disrupting effects of contaminant exposure.

Human placental JEG-3 cells conserve a high P450 aromatase activity and are therefore suitable to evaluate how contaminants may interfere with the routes involved in estrogen synthesis during pregnancy. This has been traditionally assessed by measuring aromatase activity through the amount of tritiated water (3H2O) formed during the aromatization of 1ß-3H-androst-4-ene-3,17-dione (3H-AD). This work presents a greener and safer analytical approach for this purpose, which consists of the determination of the trace amounts of the steroids (estradiol, estrone, testosterone, and androstenedione) present in the culture medium. Turbulent flow chromatography coupled to liquid chromatography-tandem mass spectrometry (TFC-HPLC-MS/MS) delivered the high selectivity and sensitivity (limits of detection between 2 and 5 pg/mL) required for these measurements. Moreover, its automation allows high-throughput of samples with minimum sample handling and achieves high precision in the analysis (relative standard deviation values <6%). As a proof of concept, the method was applied to evaluate the effect of monohaloacetic acid exposure on the steroid profile of JEG-3 cells. Iodoacetic acid showed an estrogenic effect (statistically significant increase of estradiol levels compared to unexposed cells) at the highest concentration level tested (0.5 µM) that deserves further evaluation.

QuEChERS-based analytical methods developed for LC-MS/MS multiresidue determination of pesticides in representative crop fatty matrices: Olives and sunflower seeds.

Oilseed crops are greatly extended all over the world. Their high fat content can interfere during pesticide multiresidue analysis through liquid chromatography-tandem mass spectrometry (LC-MS/MS). This work aimed at overcoming this issue by developing and validating two QuEChERS-based methods for LC-MS/MS determination of 42 pesticides in two fatty food matrices: olives and sunflower seeds. Optimization of the extraction method was achieved following a 26-2 fractional factorial design in a highly cost-effective way. Validation of the multi-residue methods demonstrated improved limits of detection, below the established maximum residue levels (MRLs) for almost all compounds, good precision, and trueness, in compliance with SANTE guidelines. Application of these methods to the analysis of real samples from the Iberian Peninsula showed the presence of some pesticides of relevant environmental concern, including four compounds contained in the Pesticide Action Network International list of highly hazardous pesticides, found at levels between 0.03 ng/g and 104 ng/g.

Assessing the skin irritation and sensitizing potential of concentrates of water chlorinated in the presence of iodinated X-ray contrast media.

Chemical disinfection of water provides significant public health benefits. However, disinfectants like chlorine can react with naturally occurring materials in the water to form disinfection byproducts (DBPs). Natural levels of iodine have been reported to be too low in some source waters to account for the levels of iodinated DBPs detected. Iodinated X-ray contrast media (ICM) have been identified as a potential source of iodine. The toxicological impact of ICM present in source water at the time of disinfection has not been fully investigated. Iopamidol, iohexol, iopromide, and diatrizoate are among the ICM most frequently detected in water. In this study, source water containing one of these four ICM was chlorinated; non-chlorinated ICM-containing water samples served as controls. Reactions were conducted at an ICM concentration of 5 µM and a chlorine dose of 100 µM over 72 hr. Water concentrates (20,000-fold) were prepared by XAD-resin/ethyl acetate extraction and DMSO solvent exchange. We used the MatTek® reconstituted human epithelial skin irritation model to evaluate the water concentrates and also assessed the dermal irritation and sensitization potential of these concentrates using the LLNA:BrdU ELISA in BALB/c mice. None of the water concentrates tested (2500X) resulted in a skin irritant response in the MatTek® skin irritation model. Likewise, none of the concentrates (2500X, 1250X, 625X, 312.5X, 156.25X) produced a skin irritation response in mice: erythema was minimal; the maximum increase in ear thickness was less than 25%. Importantly, none of the concentrates produced a positive threshold response for allergic skin sensitization at any concentration tested in the LLNA:BrdU ELISA. We conclude that concentrates of water disinfected in the presence of four different ICM did not cause significant skin irritation or effects consistent with skin sensitization at the concentrations tested.

Evaluation of an outdoor pilot-scale tubular photobioreactor for removal of selected pesticides from water.

This work assesses the capacity of a microalgae-based system to remove three highly to medium polar pesticides typically found in freshwater: acetamiprid, bentazone, and propanil. Degradation of the pesticides was firstly studied individually at batch lab-scale reactors and abiotic and heated-killed controls were employed to clarify their removal pathways. At lab-scale, propanil and acetamiprid were completely removed after 7 days whereas bentazone was not removed. Four and two transformation products (TPs) were generated in the biodegradation process for acetamiprid and propanil, respectively. Then, the simultaneous removal of the pesticides was assessed in an outdoor pilot photobioreactor, operated with a hydraulic residence time of 8 days. During the steady-state, high removal efficiencies were observed for propanil (99%) and acetamiprid (71%). The results from batch experiments suggest that removal is mainly caused by algal-mediated biodegradation. Acetamiprid TPs raised throughout the operational time in the photobioreactor, while no propanil TP was detected at the pilot-scale. This suggests complete mineralization of propanil or residual formation of its TPs at concentrations below the analytical method detection limit. Aiming at biomass valorization, diverse microalgae harvesting methods were investigated for biomass concentration, and the effect of residual pesticides on the biogas yield was determined by biochemical methane potential tests. Anaerobic digestion was not inhibited by the pesticides as verified by the digestion performance. The results highlight the potential of microalgae-based systems to couple nutrient removal, biomass production, micropollutant biodegradation, and biofuel production.

Antibiotics in the Basque coast (N Spain): Occurrence in waste and receiving waters, and risk assessment (2017-2020).

The study of the presence of antibiotics in the aquatic environment is a preliminary step to analyse their possible harmful effects on aquatic ecosystems. In order to monitor their occurrence in the aquatic environment, the European Commission established in 2015, 2018, and 2020 three Watch Lists of substances for Union-wide monitoring (Decisions (EU) 2015/495, 2018/840, and 2020/1161), where some antibiotics within the classes of macrolides, fluoroquinolones and penicillins were included. In the Basque coast, northern Spain, three macrolide antibiotics (erythromycin, clarithromycin, azithromycin) and ciprofloxacin were monitored quarterly from 2017 to 2020 (covering a period before and after the COVID19 outbreak), in water samples collected from two Waste Water Treatment Plants (WWTPs), and three control points associated with receiving waters (transitional and coastal water bodies). This work was undertaken for the Basque Water Agency (URA). The three macrolide antibiotics in water showed a frequency of quantification >65 % in the Basque coast, with higher concentrations in the WWTP emission stations than in receiving waters. Their frequency of quantification decreased from 2017 to 2020, as did the consumption of antibiotics in Spanish primary care since 2015. Ciprofloxacin showed higher frequencies of quantification in receiving waters than in wastewaters, but the highest concentrations were observed in the WWTP emission stations. Although consumption of fluoroquinolones (among which is ciprofloxacin) in primary care in the Basque Country has decreased in recent years, this trend was not observed in the waters sampled in the present study. On the other hand, concentrations of clarithromycin, azithromycin, and ciprofloxacin in receiving waters exceeded their respective Predicted No-Effect Concentrations, so they could pose an environmental risk. These substances are widely used in human and animal medicine, so, although only ciprofloxacin is included in the third Watch List, it would be advisable to continue monitoring macrolides in the Basque coast as well.