Spatio-temporal variation and ecological risk assessment of microplastics along the touristic beaches of a mediterranean coast transect (Valencia province, East Spain).

Annually, the Mediterranean region attracts around one-third of the global coastal tourism, which is acknowledged as a substantial contributor to plastic pollution. Coastal municipalities mitigate this through periodic sand and shore cleaning. However, the efficacy of these measures remains uncertain. In this study, the occurrence of MPs (10 µm-5 mm) in sand from seven different, regularly cleaned, touristic beaches of the coastline of Valencia province (E Spain) was assessed. Two different sampling campaigns were performed in winter and in summer (2022) to compare the results and understand the influence of the high touristic activity, as well as, the efficiency of the measures taken against MPs pollution. The methodology used was designed specifically for the matrix and employed density separation using a Sediment Microplastic Isolation (SMI) Unit. In addition to conventional visual inspection and ATR-FTIR, automatic quantification and identification of the polymers of lower size was performed by µFTIR. The average MPs concentration in the summer (339 ± 92 MP kg-1 by stereomicroscopy and 339 ± 189 MP kg-1 by µFTIR) was significantly higher than in the winter (71 ± 92 MP kg-1 and 143 ± 85 MP kg-1) (p < 0.05). The combination of these analytical tools provides comprehensive information about the MPs present in beach sand. Fibers were the most abundant form of MPs, while most of the polymers analyzed were polyethylene (PE) and halogenated polystyrene (Cl-PS and Br-PS) with food packaging, swimming equipment and fishing nets being their most probable sources. Ecological risk assessment was performed through the Pollution Load Index (PLI), the Hazardous Index (HI) and the Risk Quotient (RQ), with the results indicating potential risk that ranges from moderate to high depending on the applied approach.

Development of multi-residue extraction procedures using QuEChERS and liquid chromatography tandem mass spectrometry for the determination of different types of organic pollutants in mussel.

This study aimed to develop multi-residue methods for the extraction of organic pollutants in mussels (Mytilus galloprovincialis), including 11 pharmaceuticals, 5 pesticides, 5 perfluoroalkyl substances (PFASs) and 2 illicit drugs. The combination of 4 different QuEChERS methods and 12 clean-ups (a total of 44 combinations) was tested. QuEChERS included acidified (AQ), non-acidified (SQ) and their miniaturized versions. The clean-ups included 6 different conventional dispersive solid phase extraction (dSPE) plus 2 enhanced matrix removal (EMR-Lipid) and 4 SPE procedures (including sorbents focused on phospholipid removal and polymer-based). After sample analysis via HPLC-MS/MS, the three methods that provided the best results were validated in terms of linearity, accuracy, precision, sensitivity and matrix effect. The methods selected were the combination of (i) SQ and EMR-Lipid, (ii) AQ and Z-sep+ bulk-based dSPE and (iii) AQ and graphitized carbon black (GCB)-based dSPE. Recoveries at two concentration levels (50 and 500 ng/g) ranged 54-124%, 59-124% and 60-127%, respectively, and limits of quantification (LOQs) were < 30 ng/g for most analytes using any of the methods. The three methods were tested in non-spiked mussel samples purchased in local markets, but organic pollutants were not detected in any sample. However, the methods probed to successfully extract a wide range of organic pollutants families in mussel samples from the market and from bioaccumulation trials.

Multi-residue extraction to determine organic pollutants in mussel hemolymph.

This study assesses the extraction of eleven pharmaceuticals, five pesticides, five perfluoroalkyl substances, and two illicit drugs in hemolymph from (Mytilus Galloprovincialis). Four extraction procedures using Phree™ Phospholipid Removal cartridges were tested using different volumes of methanol (400 and 600 µL) and acetonitrile (300 and 450 µL). The pollutants were determined by high-performance liquid chromatography-tandem mass spectrometry. The use of methanol gave several problems during the extraction procedure, such as longer times and sample loss. Three methods (acetonitrile 300 and 450 µL; and methanol 600 µL) were validated. Recoveries at three concentration levels (5, 50, and 100 ng/mL) ranged 35.1-129.0 and 29.3-133.0% for acetonitrile 300 and 450 µL, respectively, while recoveries for methanol 600 µL ranged 52.2-166.0%. Limits of detection were < 10 ng/mL for most analytes using any of the methods. Methanol 600 µL was the only method capable to extract the illicit drug 4-methoxyphencyclidine and provided a better peak shape and higher signal-noise ratio. When applied to non-spiked samples from local markets salicylic acid and diclofenac were detected at 33.50-97.79 and 28.30-30.31 ng/mL respectively. To our knowledge, there are no methods to determine organic contaminants in hemolymph and this is the first application of Phree™ cartridges for mussel hemolymph extraction.

Determination of organophosphate flame retardants in soil and fish using ultrasound-assisted extraction, solid-phase clean-up, and liquid chromatography with tandem mass spectrometry.

A solid-liquid extraction method in combination with high-performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean-up by solid-phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50-121% for soil and 47-123% for biota, both with high precision (RSDs <12% in soil and <23% in biota). The method limits of detection ranged from 0.06 to 0.20 ng/g dry weight and between 0.02 and 0.30 ng/g wet weight for soil and biota samples, respectively. However, samples with a high lipid content produce several problems as solid-phase extraction cartridge clogging that increase variability and analysis time. The method was successfully applied for the determination of organophosphorus flame retardants in soil and fish from L'Albufera Natural Park (Valencia, Spain). Target compounds were detected in all soil and fish samples with values varying from 13.8 to 89.7 ng/g dry weight and from 3.3 to 53.0 ng/g wet weight, respectively.

Analysis of the presence of perfluoroalkyl substances in water, sediment and biota of the Jucar River (E Spain). Sources, partitioning and relationships with water physical characteristics.

The presence, sources and partitioning of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C10 sulfonates and C8 sulfonamide) were assessed in water, sediment, and biota of the Jucar River basin (E Spain). Considering the three matrices, perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (PFOS) were the most frequent compounds, being remarkable the high occurrence of short-chain PFASs (C≤8), which are intended to replace the long-chain ones in several industrial and commercial applications. In general, all samples were contaminated with at least one PFAS, with the exception of three fish samples. Mean concentrations detected in sediments (0.22-11.5ng g(-1)) and biota (0.63-274µgkg(-1)) samples were higher than those measured in water (0.04-83.1ngL(-1)), which might suggest (bio) accumulation. The occurrence of PFAS is related to urban and industrial discharges (Cuenca city in the upper part of basin, and car's factory, and effluents of the sewage treatment plant (STP) of Alzira, in the lower part). Increasing pollution gradients were found. On the other hand, higher contamination levels were observed after regulation dams of the catchment pointing out their importance in the re-distribution of these contaminants. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). PFAS concentrations found in this study can be considered in acceptable levels if compared to existing Regulatory Legislation and, consequently, they do not pose an immediate human health risk.

Optimization and comparison of several extraction methods for determining perfluoroalkyl substances in abiotic environmental solid matrices using liquid chromatography-mass spectrometry.

In this study, four extraction methods of perfluoroalkyl substances (PFASs) in soils and sediments were validated and compared in order to select the one that provides the best recoveries and the highest sensitivity. The determination of PFASs was carried out by liquid chromatography-tandem mass spectrometry. The extraction methods compared were based on (i) an aqueous solution of acetic acid and methanol (recoveries 44-125%, relative standard deviation (RSD) <25%), (ii) methanol (34-109%, <25%), (iii) sodium hydroxide digestion (24-178%, <49%), and (iv) ion pair (35-179%, <31%). The best results were obtained with methanol extraction, which recovered a greater number of PFASs and provided values between 45-103% in sediment and 34-109% in soil with RSDs <25% and limits of quantification (LOQs) between 0.02-0.31 and 0.01-6.00 ng g(-1), respectively. The selected method was successfully applied to Segura River sediments and soil samples taken near the Turia River. This study demonstrates the presence of PFASs in the studied rivers of the Valencian Community (0.07-14.91 ng g(-1) in Segura River sediments; 0.02-64.04 ng g(-1) in Turia River soils). Graphical Abstract Selected matrices and extraction methods for determination of perfluoroalkyl substances.

Trace elements and legacy and emerging organic contaminants concentrations datasets in sediments cores in L'Albufera Natural Park (Valencia, East of Spain): Association with "in-deep" sediment characteristics and risk assessment to the aquatic biota.

The chronological information provided by sediment cores about the beginning and evolution of anthropogenic contaminants is crucial for understanding the influence of humans on the environment. The dataset provides information about the vertical distribution of heavy metals (HMs), metalloids and various organic contaminants (OCs) including contemporary contaminants of emerging concern (CECs), such as pharmaceuticals and personal care products (PPCPs) and pesticides; as well as persistent organic contaminants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), perfluoroalkyl substances (PFASs), organophosphorus flame retardants (OPFRs) in sediment cores of two different sampling areas (North and South) of L'Albufera lake. Additional information about the 14C-data of the organic matter present in the different layers of the sediment cores, and the 14C-data of the seashells found in some of them are shown. The dataset includes physico-chemical analyses of sediment characteristics at the different selected depth levels such as Organic Carbon (Corg), Inorganic Carbon (IC), Total Nitrogen (TN), Total Sulphur (TS) and texture. Furthermore, ecological risk assessment of these contaminants in surface sediment layers is performed to ascertain is potential toxicity. These data supplement the findings presented and considered in the research article "Exploring Organic and Inorganic Contaminant Histories in Sediment Cores Across the Anthropocene: Accounting for Site/Area Dependent Factors". Therefore, these data altogether are useful for researchers seeking to assess long-term impact of contamination.

Exploring organic and inorganic contaminant histories in sediment cores across the anthropocene: Accounting for site/area dependent factors.

Sedimentary records help chronologically identify anthropogenic contamination in environmental systems. This study analysed dated sediment cores from L'Albufera Lake (Valencia, Spain), to assess the occurrence of heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), perfluoroalkyl substances (PFASs), organophosphorus flame retardants (OPFRs), pesticides and pharmaceuticals and personal care products (PPCPs). The results evidence the continuing vertical presence of all types of contaminants in this location. The sediment age was difficult to establish. However, the presence of shells together with an historical estimation and the knowledge of sedimentary rates could help. HMs contents are higher in the upper layer reflecting the most recent increase of the industrial and agricultural practices in the area since the middle 20th century. Higher availability index of these HMs in the upper sediment layers is associated with point and diffuse contamination sources in the area. PAHs and OPFRs were homogeneous distributed through the sediments with few exceptions such as phenanthrene in the North and fluoranthene in the South. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) were detected throughout the sediment core while short-chain PFASs (except perfluoropentanoic acid (PFPeA)) were detected only in the top layer. Pesticides and PPCPs showed appreciable down-core mobility. The vertical concentration profiles of organic contaminants did not exhibit a clear trend with depth, then, it is difficult to develop a direct relationship between sediment age and contaminant concentrations, and to elucidate the historical trend of contamination based on dated sediment core. Consequently, linking contaminant occurrence in sediments directly to their historical use is somewhat speculative at least in the conditions of L'Albufera Lake.

Oral cancer, HPV infection and evidence of sexual transmission.

The incidence of oropharyngeal cancer and oral cancer is growing worldwide, both in young non-smokers and in young non-drinkers (smoking and drinking are considered the main risk factors). Epidemiologic studies suggest a strong association between the infection by human papillomavirus (HPV), especially types 16 and 18 (high oncological risk) which have already demonstrated their etiological role in anal tumours as well as in cervix cancer. There is clear epidemiologic evidence that both types of tumours relate to changes in sexual behaviour and that both are linked to sexual transmission of HPV. The number of oral and oropharyngeal cancer cases is rising nowadays, especially among young individuals with no typical toxic habits, such as tobacco and/or alcohol. In this review we set out to update the aspects related to the onset of oral cancer, its relationship with HPV infection and whether this association may be due to the sexual transmission of the virus.

Estimation of legal and illegal drugs consumption in Valencia City (Spain): 10 years of monitoring.

Wastewater-based epidemiology (WBE) approach provides objective, quantitative, near real-time profiles of illicit drug consumption by monitoring the concentration of unchanged parent drugs or their metabolites entering the municipal sewage system. Valencia is the third most populous city in Spain (an important country for the use and transit of several of these drugs). Estimations of consumption over long periods of time will help get better understanding of spatial and temporal trends in the use of licit and illicit drugs. Accordingly, applying the "best practice" protocol, 16 drugs of abuse and metabolites were monitored in this study, and 8 were daily measured during one-two weeks between 2011 and 2020 at the inlet of three wastewater treatment plants of Valencia City. Analysis of the selected compounds was performed by liquid chromatography-triple quadrupole mass spectrometry, and the concentrations obtained were used to back-calculate the consumption data. Cannabis, tobacco, and cocaine were the most consumed drugs whereas opioids were less used. Cannabis and cocaine consumption are on average 2.7-23.4 and 1.1-2.3 g/day/1000inh, respectively, and their use tended to increase since 2018. Weekly profiles were characterized by higher consumption of cocaine, ecstasy, and heroin during weekends compared to weekdays. Similarly, during "Las Fallas" (main local festivity), increased use of cocaine and amphetamine-type stimulants, mainly MDMA, was measured. WBE proved to be an objective and useful methodology to get more insight on temporal drugs of abuse consumption, and the changes derived from local festivities.

Wild and ruderal plants as bioindicators of global urban pollution by air, water and soil in Riyadh and Abha, Saudi Arabia.

Recently, environment pollution around the globe has increased because of anthropogenic activities. As part of the biota, plants can assimilate the compounds present in air, water and soil and respond to changes in surround conditions, for that, they can be used as bioindicators of global pollution. However, urban plants' ability to monitor organic pollutants in air, soil, and water have not been profoundly studied yet. Anthropogenic contamination produced by five different types of pollutants [polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products (PPCPs), perfluoroalkyl substances (PFASs), pesticides and organophosphorus flame retardants (OPFRs)] has been studied in Riyadh and Abha areas (Saudi Arabia). In addition to the points in both cities, a control point located in the Asir National Park (close to Abha), which is little affected by human activity, was used. The 5 groups of contaminants were found with different but high detection frequencies from 85 % to 100 % in wild and ruderal plants. PAHs were detected in all the analyzed samples at the highest average sum of concentrations (ΣPAHs) 1486 ng·g-1 dry weight (d.w.). Statistically significant differences were obtained between Riyadh, Abha and the point located in the national park (p < 0.05). ΣPAHS in Riyadh >> ΣPAHs in Abha > ΣPAHs in the National Park. Values of the average sum of concentrations for the other groups of contaminants ΣPPCPs, ΣPFASs, Σpesticides and ΣOPFRs were 420.5, 171, 48 and 47 ng g-1 d.w., respectively. High values of PPCPs are due to the presence of salicylic acid. Differences in the average sum of each type of contaminant concentrations between cities were not statistically significant. The results of this assessment of wild and ruderal plants as bioindicators for 5 types of organic contaminants suggest that they can be used to monitor anthropogenic contaminants in the terrestrial environment.

Role of the dental surgeon in the early detection of adults with underlying HIV infection/AIDS.

A review is made of the late diagnosis of human immunodeficiency virus (HIV) infection, a subject of growing interest in public health. It has been estimated that in Europe 30% of all HIV-infected people are unaware of their seropositive condition, and this in turn is associated with a poorer long-term disease prognosis and an increased risk of transmission to other individuals. The role of the dental surgeon in this context could be of great importance, since there are many oral lesions that can suggest the existence of underlying infection. The study also addresses the controversial subject of rapid HIV testing, and whether these tests should be performed on a routine basis in the dental clinic, or whether it is preferable to refer the patient to a specialized center.

Bioaccumulation of emerging contaminants in mussel (Mytilus galloprovincialis): Influence of microplastics.

Coastal environments are heavily influenced by human activities. Chemical substances considered as emerging contaminants (ECs) are one of the most important indicators of the anthropic influence on the environment, and they have recently shown to interact with microplastics (MPs). Mussels are suitable for in-lab bioacumulation studies providing insight about the occurrence and fate of contaminants in the organisms. In this study, bioacummulation of 20 chemical substances catalogued as ECs, including pharmaceuticals and personal care products (PPCPs), pesticides, and perfluoroalkyl substances (PFASs) in Mytilus galloprovincialis was assessed, with or without the influence of the presence of MPs. Mussels were distributed in three groups: control (B), exposed to ECs (C) and exposed to ECs and polyethylene MPs (C+M). The study was carried out for 58 days separated in two stages (i) exposure during days 0-28, and (ii) depuration during days 29-58. Visceral mass and haemolymph of the mussels were extracted separately, using QuEChERS and solid phase extraction (SPE), respectively. Then, extracts were analysed via UHPLC-MS/MS. Results showed that 3 PPCPs, 4 pesticides and 3 PFASs accumulated in visceral mass with bioconcentration factors (BCFs) ranging 6.7-15000 L/kg/d. In addition, 2 PPCPs, 2 pesticides and PFPeA were detected in haemolymph showing BCFs ranging 0.9-3.3 L/kg/d. When comparing C and C+M, MPs worked as a vector for the accumulation of the PFASs: PFOA, PFOS, PFDA and PFPeA; showing higher BCFs in the presence of MPs. Furthermore, the elimination of PFDA and PFOS was slower in the mussels exposed to MPs. On the other hand, the pesticides terbuthylazine and chlorpyrifos showed lower BCFs and more rapid elimination in the mussels exposed to MPs.

A reconnaissance study of pharmaceuticals, pesticides, perfluoroalkyl substances and organophosphorus flame retardants in the aquatic environment, wild plants and vegetables of two Saudi Arabia urban areas: Environmental and human health risk assessment.

In this study, the occurrence of 12 organophosphorus flame retardants (OPFRs), 64 pesticides, 21 perfluoroalkyl substances (PFASs) and 34 pharmaceuticals and personal care products (PPCPs) in surface water, sediments and vegetation collected from seven locations along the South Riyadh and six locations along the Al-Jubail industrial city (Saudi Arabia) were reported. The median of the concentrations of Æ©OPFRs, Æ©Pesticides, Æ©PFASs and Æ©PPCPs in water was 297, 231, 29.7 and 3794 ng L-1, respectively, in sediments 56.2, 40.4, 5.66 and 419 ng g-1 d.w., in crops for human consumption of 45.6, 42.0, 0.46 and 42.0 ng g-1, in farm crops of 13.4, 57.5, 3.2 and 637 ng g-1, and in natural vegetation of 51.7, 10.3, 1.88 and 1580 ng g-1. Predominant compounds in all matrices were tris-(1,3-dichloro-2-propyl)phosphate (TClPP), acetamiprid, imidacloprid, caffeine, bisphenol A (BPA), diclofenac and ibuprofen. Tris(2-butoxyethyl) phosphate (TBEP), tris-(2-ethylhexyl)phosphate (TPhP), perfluoroctanoic acid (PFOA), perfluoroalkyl sulfonate (PFOS) and paracetamol were also in many samples but at low concentrations. The contaminants' levels showed similar values in both cities. However, pesticide levels were significantly higher in surface water (p < 0.05) and lower in natural vegetation (p < 0.05) of Riyadh than those of Al-Jubail. The risk assessment for the aquatic biota showed that abamectin, diazinon (pesticides), bisphenol A and caffeine (PPCPs) had the highest risk levels. The cumulative risk assessment showed that the contaminant mixture in all water samples is of concern. As far as the risk to human health is concerned, individual contaminants did not show a significant hazard for the population. However, OPFRs and pesticide requires a closed monitoring since % of admissible daily intakes (ADIs) or reference doses (RfD) are high. This is one of the most comprehensive study covering environmental and human risk assessment of emerging contaminants carried out in Saudi Arabia.

Surgical ciliated cyst of the maxilla. Clinical case.

Surgical ciliated cyst is uncommon in Western countries but frequently reported in Asian populations as a delayed complication of surgery, with inclusion in the bone of nasal or sinus mucosa. Isolated cases have also been reported in the mandible after orthognathic surgery. We report a case in the maxillary region three years after radical sinus surgery for chronic sinusitis. Intraoral examination revealed a small painless tumefaction with no color change in the surrounding tissues. Computed tomography demonstrated a well-defined intraosseous lesion lateral to the maxillary sinus. The lesion was completely excised, when histology demonstrated a pseudostratified ciliated epithelial lining. Differential diagnosis from other lesions such as an odontogenic keratocyst or inflammatory cyst were also made. This case report,uncommon in Western countries, of a surgical ciliated cyst illustrates the need for a meticulous surgical technique, proper management of complications, and routine, long-term follow-up of patients undergoing any type of sinus surgery.

Occurrence, distribution and behavior of emerging persistent organic pollutants (POPs) in a Mediterranean wetland protected area.

The analysis of perfluoroalkyl substances (PFASs) and organophosphate flame retardants (PFRs) in the different environmental compartments of a characteristic coastal wetland, the Albufera Natural Park (Valencia, Spain), is required for understanding the transport, accumulation and fate of these pollutants in an area under high anthropogenic pressure. Samples included 13 wastewater treatment plant influents, 13 effluents, 12 surface water, 19 sediment samples and 10 fish individuals from the Albufera Natural Park and the surrounding area. Tris(2-chloroisopropyl) phosphate (TCIPP) and perfluorooctane sulfonate (PFOS) were at the highest concentrations in water, 330.2 ng L-1 and 47.8 ng L-1, respectively. In fish and sediment PFOS was also the most detected while perfluorooctanoic acid (PFOA) was in all types of water. Higher levels of target compounds (mainly PFASs) in wastewater effluents compared to influent suggested both, formation from precursors during treatment and poor removal efficiency. Mean levels of PFOS in water and fish were higher than the environmental quality standards (EQS) established by the European Union Directive 2013/39/EU. The influence of the metropolitan area of Valencia and its surrounding industrial belt could explain the significantly higher levels reported in the northern part (influenced by the Turia River).

High resolution image in bone biology II. Review of the literature.

Bone microstructure has usually been assessed by obtaining samples invasively and analyzing them with conventional histomorphometric methods. Improvements in high-resolution image acquisition systems have enabled non-invasive assessment of bone morphology and a more precise 3-D evaluation by means of "virtual biopsies", permitting bone assessment in regeneration or remodeling processes. Among other applications, this imaging technique can be used for the ultrastructural analysis of bone and for studies of regeneration techniques, biomechanics in bone physiotherapy, and periimplant bone healing. This review describes the different applications of high-resolution imaging techniques in bone biology and the morphometric results obtained with these images in mechanobiology in general and maxillary bone in particular.

High resolution image in bone biology I. Review of the literature.

Bone microstructure has usually been assessed by obtaining samples invasively and analyzing them with conventional histomorphometric methods. Improvements in high-resolution image acquisition systems have enabled non-invasive assessment of bone morphology and a more precise 3-D evaluation by means of "virtual biopsies", permitting bone assessment in regeneration or remodeling processes. This review describes the characteristics and limitations of bone assessment using different high-resolution image systems (synchrotron-radiation computed tomography, micro-computed tomography, acoustic scanning microscope; micro-magnetic resonance imaging). Morphometric variables that can be obtained from these images are reported and compared with conventional histomorphometric variables.

Pesticide occurrence in the waters of Júcar River, Spain from different farming landscapes.

A combined methodology to identify and quantify farming chemicals in the entire Júcar River basin has been developed. The procedure consisted of the application of environmental forensic criteria associating laboratory analytical samples, cartographic analysis using Geographical Information Systems (GIS) and synthetic statistical analysis. Sampling involved the collection of 15 samples in surface waters distributed alongside the Júcar River and its two main tributaries (Cabriel and Magro Rivers). The analytical procedure involves generic sample extraction and selective determination of up to 50 target pesticides by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Geographical analysis was performed by mixing both sampling points with analytical results and land use-cover layers for the year 2011. PCA and descriptive statistical analysis was further performed combining land use/cover information and pesticides results to determine correlation between dominant agricultural practices (irrigation and rain fed farming) and location of sampling points. Out of 50 pesticides, 20 were identified and 18 presented concentrations higher than the limits of quantification in surface waters, with a large dispersion in concentrations: from 0.05ng/L (terbuthylazine-2 hydroxy) to 222.45ng/L (imazalil). Statistical analyses reveals that there is a correlation between the percentage of land devoted to irrigation farming, whereas correlations are weaker when analysing the relationship of pesticides in rain fed dominated areas.

Emerging contaminants related to the occurrence of forest fires in the Spanish Mediterranean.

Forest fires can be a source of contamination because, among others, of the use of chemicals to their extinction (flame retardants, FRs), or by the production of Polycyclic Aromatic Hydrocarbons (PAHs) derived from high temperature alteration of organic matter. Up to our knowledge, this study is the first to assess the direct (PAHs 16 on the USA EPA's priority list), and indirect [tri- to hepta- brominated diphenyl ethers (PBDEs), organophosphorus flame retardants (PFRs) and perfluoroalkyl substances (PFASs)] contamination related to forest fires. The abundance and distribution of these contaminants were monitored on two Mediterranean hillslopes, one burned and one unburned, near Azuébar (SE Spain). Samples were taken in the foot, middle, and top of the slope, at two depths, and in two environments (under canopy and bare soil). Sediments were collected from sediment fences after erosive rainfall events. Most of the screened compounds were found in both, burned and control hillslopes, though significant differences were found between both. In burned soil, low concentrations of PBDEs (maximum ΣPBDEs: 7.3ngg-1), PFRs (664.4ngg-1) and PFASs (56.4ngg-1) were detected in relation to PAHs (Σ16 PAHs=1255.3ngg-1). No significant influence of the hillslope position was observed for any of the contaminants but differences based on depth and vegetation presence tended to be significant, particularly for the PAHs. After the first erosive event, concentrations of PBDEs and PAHs were higher in sediment than in soil (ΣPBDEs: 17.8ngg-1 and Σ16 PAHs=3154.2ngg-1) pointing out the importance of connectivity processes, especially shortly after fire.