Part I: temporal and spatial distribution of multiclass pesticide residues in lake waters of Northern Greece: application of an optimized SPE-UPLC-MS/MS pretreatment and analytical method

Toxic interactions at the physiological and biochemical levels of green algae under stress of mixtures of three azole fungicides

Assessing the interactions between environmental pollutants and these mixtures is of paramount significance in understanding their negative effects on aquatic ecosystems. However, existing research often lacks comprehensive investigations into the physiological and biochemical mechanisms underlying these interactions. This study aimed to reveal the toxic mechanisms of cyproconazole (CYP), imazalil (IMA), and prochloraz (PRO) and corresponding these mixtures on Auxenochlorella pyrenoidosa by analyzing the interactions at physiological and biochemical levels. Higher concentrations of CYP, IMA, and PRO and these mixtures resulted in a reduction in chlorophyll (Chl) content and increased total protein (TP) suppression, and malondialdehyde (MDA) content exhibited a negative correlation with algal growth. The activity of catalase (CAT) and superoxide dismutase (SOD) decreased with increasing azole fungicides and their mixture concentrations, correlating positively with growth inhibition. Azole fungicides induced dose-dependent apoptosis in A. pyrenoidosa, with higher apoptosis rates indicative of greater pollutant toxicity. The results revealed concentration-dependent toxicity effects, with antagonistic interactions at low concentrations and synergistic effects at high concentrations within the CYP-IMA mixtures. These interactions were closely linked to the interactions observed in Chl-a, carotenoid (Car), CAT, and cellular apoptosis. The antagonistic effects of CYP-PRO mixtures on A. pyrenoidosa growth inhibition can be attributed to the antagonism observed in Chl-a, Chl-b, Car, TP, CAT, SOD, and cellular apoptosis. This study emphasized the importance of gaining a comprehensive understanding of the physiological and biochemical interactions within algal cells, which may help understand the potential mechanism of toxic interaction.

Benzimidazole fungicide biotransformation by comammox Nitrospira bacteria: Transformation pathways and associated proteomic responses

Benzimidazole fungicides are frequently detected in aquatic environments and pose a serious health risk. Here, we investigated the metabolic capacity of the recently discovered complete ammonia-oxidizing (comammox) Nitrospira inopinata and kreftii to transform a representative set of benzimidazole fungicides (i.e., benzimidazole, albendazole, carbendazim, fuberidazole, and thiabendazole). Ammonia-oxidizing bacteria and archaea, as well as the canonical nitrite-oxidizing Nitrospira exhibited no or minor biotransformation activity towards all the five benzimidazole fungicides. In contrast, the investigated comammox bacteria actively transformed all the five benzimidazole fungicides, except for thiabendazole. The identified transformation products indicated hydroxylation, S-oxidation, and glycosylation as the major biotransformation pathways of benzimidazole fungicides. We speculated that these reactions were catalyzed by comammox-specific ammonia monooxygenase, cytochrome P450 monooxygenases, and glycosylases, respectively. Interestingly, the exposure to albendazole enhanced the expression of the antibiotic resistance gene acrB of Nitrospira inopinata, suggesting that some benzimidazole fungicides could act as environmental stressors that trigger cellular defense mechanisms. Altogether, this study demonstrated the distinct substrate specificity of comammox bacteria towards benzimidazole fungicides and implies their significant roles in the biotransformation of these fungicides in nitrifying environments.

Screening of pesticides and emerging contaminants in eighteen Greek lakes by using target and non-target HRMS approaches: Occurrence and ecological risk assessment

Lakes, albeit ecosystems of vital importance, are insufficiently investigated with respect to the degradation of water quality due to the organic micropollutants load. As regards Greece, screening of lake waters is scarce and concerns a limited number of contaminants. However, understanding the occurrence of contaminants of emerging concern (CECs) and other micropollutants in lakes is essential to appraise their potential ecotoxicological effects. The aim of this study was to deploy a multiresidue screening approach based on liquid chromatography-high-resolution mass spectrometry (HRMS) to get a first snapshot for >470 target CECs, including pesticides, pharmaceuticals, personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), as well as organophosphate flame retardants (OPFRs) in eighteen Greek lakes in Central, Northern and West Northern Greece. The omnipresent compounds were DEET (N,N-diethyl-meta-toluamide), caffeine and TCPP (tris (1-chloro-2-propyl) phosphate). Maximum concentrations varied among the different classes. DEET was detected at a maximum average concentration of >1000 ng/L in Lake Orestiada, while its mean concentration was estimated at 233 ng/L. The maximum total concentrations for pesticides, PPCPs, PFASs, and OPFRs were 5807, 2669, 33.1, and 1214 ng/L, respectively, indicating that Greek lakes are still threatened by the intense agricultural activity. Besides, HRMS enabled a non-target screening by exploiting the rich content of the full-scan raw data, allowing the 'discovery' of tentative candidates, such as surfactants, pharmaceuticals, and preservatives among others, without reference standards. The potential ecotoxicity was assessed by both the risk quotient method and ECOSAR (Ecological Structure Activity Relationships) revealing low risk for most of the compounds.

Quality Control of Emerging Contaminants in Marine Aquaculture Systems by Spot Sampling-Optimized Solid Phase Extraction and Passive Sampling

The presence of organic pollutants such as pesticides and pharmaceuticals in the aquatic environment, and especially in regions where fish farms are installed, is a matter of major importance due to their possible risks to ecosystems and public health. The necessity of their detection leads to the development of sensitive, reliable, economical and environmentally friendly analytical methods for controlling their residue in various environmental substrates. In the present work, a solid-phase extraction method was developed, optimized and validated for the analysis of 7 pesticides and 25 pharmaceuticals in seawater using LC-HR-LTQ/Orbitrap-MS. The method was then applied in seawater samples collected from an aquaculture farm located in the Ionian Sea, Greece, in order to evaluate environmental pollution levels. None of the pesticides were detected, while paracetamol was the only pharmaceutical compound that was found (at trace levels). At the same time, passive sampling was conducted as an alternative screening technique, showing the presence of contaminants that were not detected with spot sampling. Among them, irgarol was detected and as far as pharmaceuticals is concerned, trimethoprim and sulfadiazine were found; however, all positive findings were at the very low ppt levels posing no threat to the aquatic environment.

Assessment of Environmental Pollution and Human Exposure to Pesticides by Wastewater Analysis in a Seven-Year Study in Athens, Greece

Pesticides have been used in large amounts around the world for decades and are responsible for environmental pollution and various adverse effects on human health. Analysis of untreated wastewater can deliver useful information on pesticides’ use in a particular area and allow the assessment of human exposure to certain substances. A wide-scope screening method, based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry, was applied, using both target and suspect screening methodologies. Daily composite influent wastewater samples were collected for seven or eight consecutive days in Athens between 2014 and 2020 and analyzed for 756 pesticides, their environmental transformation products and their human metabolites. Forty pesticides were quantified at mean concentrations up to 4.9 µg/L (tralkoxydim). The most abundant class was fungicides followed by herbicides, insect repellents, insecticides and plant growth regulators. In addition, pesticide transformation products and/or metabolites were detected with high frequency, indicating that research should be focused on them. Human exposure was evaluated using the wastewater-based epidemiology (WBE) approach and 3-ethyl-carbamoyl benzoic acid and cis-1,2,3,6-tetrahydrophthalimide were proposed as potential WBE biomarkers. Wastewater analysis revealed the presence of unapproved pesticides and indicated that there is an urgent need to include more transformation products in target databases.

A Simple Method for the Determination of Triazines from Seawater in Accordance with the Directive 2013/39/EU

Since the Directive 2013/39/EU included terbutryn to the list of priority substances of all water bodies, a previous method based on dispersive liquid-liquid micro-extraction (DLLME) for the determination of triazines in seawater has been modified. The main change consisted on the use of tandem mass spectrometry instead of diode array as detection technique. Due to the higher sensitivity of mass detector, sample volume was reduced and extraction solvent volume was optimized. The optimum extraction conditions were 5 mL of sample, 50 µL of 1-octanol and an agitation step instead of disperser solvent. The obtained analytical recoveries (73%-101% with relative standard deviations below 4%) meeting the requirements. The limits of quantification (between 0.016 and 0.021 µg L^-1) were more than 10 times lower than the limit set by the European Directive 2013/39/EU for terbutryn (0.34 µg L^-1). The proposed method was applied to the determination of the target compounds in seawater samples from A Coruña (Galicia, NW of Spain).

Fate and ecotoxicological effects of pyriproxyfen in aquatic ecosystems

Pyriproxyfen is an insect growth regulator acting as larvicide against a large spectrum of public health insect pests, especially dipterans. It is also widely used in agriculture and horticulture for the control of many insect species. Disrupting the endocrine system by mimicking the activity of the juvenile hormone, pyriproxyfen interferes with metamorphosis in insects and prevents them from reaching maturity and reproducing. Because the aquatic ecosystems can be directly or indirectly contaminated by pyriproxyfen, the goal of this study was to establish the aquatic ecotoxicological profile of pyriproxyfen and to identify the gaps that need to be filled. Pyriproxyfen is photodegraded quickly in water. In the absence of organic matter, its persistence in aerobic water media is also limited especially with high temperature and sunlight. Analysis of the laboratory and in situ results for more than 60 aquatic algae, plants, invertebrates, and vertebrates shows that the toxicity of pyriproxyfen is highly variable including within a same taxonomical group. Abiotic and biotic factors can highly influence the toxicity of the molecule. Pyriproxyfen disrupts the development of numerous species and adversely impacts various physiological events. It can also disturb the behavior of the organisms such as their predatory and swimming performances. Although some experimental studies focus on the environmental fate of pyriproxyfen metabolites, those dealing with their aquatic ecotoxicity assessment are scarce. In the same way, the limited number of studies dealing with the search of pyriproxyfen residues in lake, river, and other natural aquatic media does not include the identification of the metabolites.

Biocide emissions from building materials during wet weather: identification of substances, mechanism of release and transfer to the aquatic environment

Biocides are added to or applied on building materials to prevent microorganisms from growing on their surface or to treat them. They are leached into building runoff and contribute to diffuse contamination of receiving waters. This review aimed at summarizing the current state of knowledge concerning the impact of biocides from buildings on the aquatic environment. The objectives were (i) to assess the key parameters influencing the leaching of biocides and to quantify their emission from buildings, (ii) to determine the different pathways from urban sources into receiving waters and (iii) to assess the associated environmental risk. Based on consumption data and leaching studies, a list of substances to monitor in receiving water was established. Literature review of their concentrations in the urban water cycle showed evidences of contamination and risk for aquatic life, which should put them into consideration for inclusion to European or international monitoring programs. However, some biocide concentration data in urban and receiving waters is still missing to fully assess their environmental risk, especially for isothiazolinones, iodopropynyl carbamate, zinc pyrithione and quaternary ammonium compounds, and little is known about their transformation products. Although some models supported by actual data were developed to extrapolate emissions on larger scales (watershed or city scales), they are not sufficient to prioritize the pathways of biocides from urban sources into receiving waters during both dry and wet weathers. Our review highlights the need to reduce emissions and limit their transfer into rivers and reports several solutions to address these issues.

Occurrence and overlooked sources of the biocide carbendazim in wastewater and surface water

Carbendazim is a fungicide commonly used as active substance in plant protection products and biocidal products, for instance to protect facades of buildings against fungi. However, the subsequent occurrence of this fungicide and potential endocrine disruptor in the aqueous environment is a major concern. In this study, high resolution mass spectrometry shows that carbendazim can be detected with an increasing abundance from the source to the mouth of the River Rhine. Unexpectedly, the abundance of carbendazim correlates poorly with that of other fungicides used as active ingredients in plant protection products (r² of 0.32 for cyproconazole and r² of 0.57 for propiconazole) but it correlates linearly with that of pharmaceuticals (r² of 0.86 for carbamazepine and r² of 0.89 for lamotrigine). These results suggest that the occurrence of carbendazim in surface water comes mainly from the discharge of treated domestic wastewater. This hypothesis is further confirmed by the detection of carbendazim in wastewater effluents (n = 22). In fact, bench-scale leaching tests of textiles and papers revealed that these materials commonly found in households could be a source of carbendazim in domestic wastewater. Moreover, additional river samples collected nearby two paper industries indicate that the discharge of their treated process effluents is also a source of carbendazim in the environment. While characterizing paper and textile as overlooked sources of carbendazim, this study also shows the biocide as a possible ubiquitous wastewater contaminant that would require further systematic and worldwide monitoring due to its toxicological properties.

Terbuthylazine and desethylterbuthylazine: Recent occurrence, mobility and removal techniques

The herbicide terbuthylazine (TBA) has displaced atrazine in most of EU countries, becoming one of the most regularly used pesticides and, therefore, frequently detected in natural waters. The affinity of TBA for soil organic matter suggests prolonged contamination; degradation leads to the release of the metabolite desethylterbuthylazine (DET), which has higher water solubility and binds more weakly to organic matter compared to the parent compound, resulting in higher associated risk for contamination of groundwater resources. Additionally, TBA and DET are chemicals of emerging concern because of their persistence and toxicity towards aquatic organisms; moreover, they are known to have significant endocrine disruption capacity to wildlife and humans. Conventional treatments applied during drinking water production do not lead to the complete removal of these chemicals; activated carbon provides the greatest efficiency, whereas ozonation can generate by-products with comparable oestrogenic activity to atrazine. Hydrogen peroxide alone is ineffective to degrade TBA, while UV/H₂O₂ advanced oxidation and photocatalysis are the most effective processes for oxidation of TBA. It has been determined that direct photolysis gives the highest degradation efficiency of all UV/H₂O₂ treatments, while most of the photocatalytic degradation is attributed to OH radicals, and TiO₂ solar-photocatalytic ozonation can lead to almost complete TBA removal in ∼30 min. Constructed wetlands provide a valuable buffer capacity, protecting downstream surface waters from contaminated runoff. TBA and DET occurrence are summarized and removal techniques are critically evaluated and compared, to provide the reader with a comprehensive guide to state-of-the-art TBA removal and potential future treatments.

A review on environmental monitoring of water organic pollutants identified by EU guidelines

The contamination of fresh water is a global concern. The huge impact of natural and anthropogenic organic substances that are constantly released into the environment, demands a better knowledge of the chemical status of Earth's surface water. Water quality monitoring studies have been performed targeting different substances and/or classes of substances, in different regions of the world, using different types of sampling strategies and campaigns. This review article aims to gather the available dispersed information regarding the occurrence of priority substances (PSs) and contaminants of emerging concern (CECs) that must be monitored in Europe in surface water, according to the European Union Directive 2013/39/EU and the Watch List of Decision 2015/495/EU, respectively. Other specific organic pollutants not considered in these EU documents as substances of high concern, but with reported elevated frequency of detection at high concentrations, are also discussed. The search comprised worldwide publications from 2012, considering at least one of the following criteria: 4 sampling campaigns per year, wet and dry seasons, temporal and/or spatial monitoring of surface (river, estuarine, lake and/or coastal waters) and ground waters. The highest concentrations were found for: (i) the PSs atrazine, alachlor, trifluralin, heptachlor, hexachlorocyclohexane, polycyclic aromatic hydrocarbons and di(2-ethylhexyl)phthalate; (ii) the CECs azithromycin, clarithromycin, erythromycin, diclofenac, 17α-ethinylestradiol, imidacloprid and 2-ethylhexyl 4-methoxycinnamate; and (iii) other unregulated organic compounds (caffeine, naproxen, metolachlor, estriol, dimethoate, terbuthylazine, acetaminophen, ibuprofen, trimethoprim, ciprofloxacin, ketoprofen, atenolol, Bisphenol A, metoprolol, carbofuran, malathion, sulfamethoxazole, carbamazepine and ofloxacin). Most frequent substances as well as those found at highest concentrations in different seasons and regions, together with available risk assessment data, may be useful to identify possible future PS candidates.

Effects of terbuthylazine-desethyl, a terbuthylazine degradation product, on red swamp crayfish (Procambarus clarkii)

Terbuthylazine is a widely used triazine pesticide. This, together with one of its degradation products, terbuthylazine-desethyl (TD), are frequently found in quantities exceeding the EU limit of 0.1μg/L in aquatic ecosystems where they might constitute a serious risk to non-target organisms. The sub-chronic effects of TD at 2.9μg/L (real environmental concentration) and at 580μg/L were investigated in a non-target aquatic species, the red swamp crayfish (Procambarus clarkii). Gill and hepatopancreas histopathology, alterations in biochemical parameters of haemolymph, oxidative damage to hepatopancreas, and changes in antioxidant biomarkers in muscle and hepatopancreas were recorded at both tested concentrations after 14days exposure. A 14day recovery period in TD-free water was not sufficient for restoration of normal parameters. Chronic terbuthylazine-desethyl exposure affected biochemical profile, and the antioxidant system, caused oxidative stress and histopathological changes in hepatopancreas of red swamp crayfish.

Active and passive sampling for the assessment of hydrophilic organic contaminants in a river basin-ecotoxicological risk assessment

This study presents a complementary approach for the evaluation of water quality in a river basin by employing active and passive sampling. Thirty-eight hydrophilic organic compounds (HpOCs) (organohalogen herbicides, organophosphorous pesticides, carbamate, triazine, urea, pharmaceuticals, phenols, and industrial chemicals) were studied in grab water samples and in passive samplers POCIS collected along Strymonas River, Northern Greece, at three sampling campaigns during the year 2013. Almost all the target compounds were detected at the periods of high rainfall intensity and/or low flow rate. The most frequently detected compounds were aminocarb, carbaryl, chlorfenviphos, chloropropham, 2,4-D, diflubenzuron, diuron, isoproturon, metolachlor, and salicylic acid. Bisphenol A and nonylphenol were also occasionally detected. The use of POCIS allowed the detection of more micropollutants than active sampling. Low discrepancy between the concentrations obtained from both samplings was observed, at least for compounds with >50 % detection frequency; thus, POCIS could be a valuable tool for the selection and monitoring of the most relevant HpOCs in the river basin. Results showed relatively low risk from the presence of HpOCs; however, the potential risk associated with micropollutants such as carbaryl, dinoseb, diuron, fenthion, isoproturon, metolachlor, nonylphenol, and salicylic acid should not be neglected.

Evaluation of two pesticide leaching models in an irrigated field cropped with corn

Pesticide leaching models is an easy and cost effective method used in the prediction of surface and groundwater pollution. In this paper, the ability of two pesticide leaching models, MACRO and PEARL, to describe soil water dynamics and atrazine's transport through the soil profile was examined. The data used for the comparison was obtained from an experiment in an irrigated corn field in the plain of the Ardas River, in north-eastern Greece. Both models were parameterized using pedotransfer functions, field and laboratory data. The uncalibrated simulation showed several discrepancies, therefore the retention curve and the sorption parameters were calibrated according to the trial and error method. The comparison of both models indicated that soil water flow was described similarly. The simulated results of atrazine's concentration were evaluated and compared to the measured concentrations at specific depths, using statistical criteria. Atrazine transport was simulated in a satisfactory manner as confirmed by model efficiency (EF) values, that are very close to unit. Coefficient of residual mass (CRM) values for both models are positive, indicating that both models underestimate the measured data. MACRO estimated higher accumulated actual evapotranspiration values, and less percolated water from soil profile than PEARL, and as a result, change in water content was higher in the latter. PEARL also predicted that half the amount of the applied mass was decayed two days earlier than the day estimated by MACRO. Generally, MACRO simulated the fate of atrazine in soil better than PEARL.