A V-shaped bis-coumarin based fluorescence probe for F- detection in tea infusions and potable water and bioimaging applications in living systems.

Fluorine (F) is a pivotal element in the formation of human dental and skeletal tissues, and the consumption of water and tea constitutes a significant source of fluoride intake. However, prolonged ingestion of water and tea with excessive fluoride content can lead to fluorosis, which poses a serious health hazard. In this manuscript, a novel turn-on fluorescent probe DCF synthesized by bis-coumarin and tert-butyldiphenylsilane (TBDPS) was introduced for detecting F- in potable water and tea infusions. By leveraging the unique chemical affinity between fluoride and silicon, F- triggers the silicon-oxygen bond cleavage in DCF, culminating in a conspicuous emission of yellow fluorescence. Validated through a succession of optical tests, this probe exhibits remarkable advantages in terms of superior selectivity, a low detection limit, a large Stokes shift, and robust interference resistance when detecting inorganic fluoride. Moreover, it can serve as portable test strips for on-site real-time identification and quantitative analysis of F-. Furthermore, the application of DCF for in-situ monitoring and imaging of F- in zebrafish and soybean root tissues proved its significant value for F- detection in both animal and plant systems. This probe potentially functions as an efficient instrument for delving into the toxic mechanisms of fluoride in physiological processes.

Total and Class-Specific Determination of Fluorinated Compounds in Consumer and Food Packaging Samples Using Fluorine-19 Solid-State Nuclear Magnetic Resonance Spectroscopy.

Hamburger wrapping paper, coated with water-based barrier coatings, used in the food packaging industry was studied by using the total organic fluorine (TOF) method based on combustion ion chromatography and fluorine-19 solid-state nuclear magnetic resonance (19F ss-NMR) spectroscopy. Although the TOF method is a fast and affordable method used to screen for per- and polyfluoroalkyl substances (PFAS), the amount of fluorine it measures is heavily dependent on the extraction step and, therefore could lead to inaccurate results. Fluorine-19 ss-NMR spectroscopy can differentiate between organic and inorganic fluorinated sources, eliminating the need for sample clean up. To illustrate this, the 19F ss-NMR spectra of clean coated paper samples that contained naturally occurring F- ions from the talc raw material and spiked samples containing perfluorooctanoic acid were compared. A range of experimental conditions was explored to improve sensitivity for low PFAS concentrations (in the order of 10-20 mg/kg). Despite the disadvantages of ss-NMR spectroscopy, such as the low limit of detection and resolution, the results demonstrate it can be a viable tool to directly detect PFAS moieties in consumer and food packaging. Therefore, 19F solid-state NMR spectroscopy challenges and complements current methods, which only provide indirect evidence of the presence of PFAS.

The influence of the acid water of the Banyupait River on the community health in Bantal village, Asembagus, Indonesia.

The pH of Mount Ijen crater water is 0-2, resulting in water that is acidic and sulfurous. A fault near the Mount Ijen Crater causes seepage so that acidic water flows into the Banyupait River. Chemical elements and heavy metals originating from the river pollute groundwater and plants. As a result, people around the river consume heavy metals. This research aims to determine the quality of river water and groundwater, as well as determine community factors that are susceptible to dental fluorosis. The methodology used is field mapping and laboratory analysis. For water samples, the Atomic Absorption Spectrophotometer (AAS) method is used. The pH of river water at the research location exceeds the quality standard, namely pH 4-5.5. Meanwhile, groundwater fluorine and sulfate elements exceed quality standards, namely fluorine of 0.6171 mg/L and 0.6870 mg/L, and sulfate ranging from 325-683 mg/L. These two elements cause symptoms of dental fluorosis. Meanwhile, the community factors most susceptible to dental fluorosis are people in the adult age category, and the last level of education is elementary school. This is because the Banyupait River water and groundwater are exposed to fluorine and sulfate water originating from seepage from the Mount Ijen Crater.

Identifying PFAS hotspots in surface waters of South Carolina using a new optimized total organic fluorine method and target LC-MS/MS.

Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants of concern due to their long persistence in the environment, toxicity, and widespread presence in humans and wildlife. Knowledge regarding the extent of PFAS contamination in the environment is limited due to the need for analytical methods that can reliably quantify all PFAS, since traditional target methods using liquid chromatography (LC)-mass spectrometry (MS) fail to capture many. For a more comprehensive analysis, a total organic fluorine (TOF) method can be used as a screening tool. We combined TOF analysis with target LC-MS/MS analysis to create a statewide PFAS hotspot map for surface waters throughout South Carolina. Thirty-eight of 40 locations sampled contained detectable concentrations of organic fluorine (above 100 ng/L). Of the 33 target PFAS analyzed using LC-MS/MS, the most prevalent were perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and perfluorohexanesulfonate (PFHxS). On average, LC-MS/MS only accounted for 2 % of the TOF measured. Locations with high TOF did not necessarily correlate to high total quantified PFAS concentrations and vice-versa, demonstrating the limitations of target PFAS analysis and indicating that LC-MS may miss highly contaminated sites. Results suggest that future surveys should utilize TOF to more comprehensively capture PFAS in water bodies.

Analysis of per- and polyfluoroalkyl substances (PFAS) in raw materials intended for the production of paper-based food contact materials - evaluating LC-MS/MS versus total fluorine and extractable organic fluorine.

Per- and polyfluoroalkyl substances (PFAS) analysis has become crucial due to their presence in the environment, their persistence and potential health risks. These compounds are commonly used in food contact materials (FCM) as a coating to provide water and grease-repellent properties. One of the pathways for PFAS to enter the human body is either through direct consumption of contaminated food or indirectly through migration from FCM into food. The purpose of this study was to investigate where the initial contamination of paper FCM occurs. We analysed paper material consisting of fresh fibre and secondary materials, intended to produce food packaging for the presence of PFAS. The samples were extracted and analysed for 23 different PFAS substances using the targeted approach with LC tandem mass spectrometry (LC-MS/MS). This analytical technique detects specific, easily ionisable PFAS with high sensitivity. However, one drawback of this approach is that it allows the identification of less than 1% of the PFAS known today. For this reason, we used combustion ion chromatography (CIC) to determine the content of extractable organic fluorine compounds (EOF) and compare it to the total fluorine content. The targeted analysis using LC-MS/MS measured an average sum concentration of PFAS of 0.17 ng g-1 sample. Our research shows that the primary PFAS contamination happens during the recycling process since all of the samples in which the targeted PFAS were measured belonged to the secondary material. The most frequently detected analytes were PFOA and PFOS, detected in 90% and 62% of the samples, respectively, followed by PFBS (in 29% of the samples). CIC showed that measured PFAS via LC-MS/MS amount to an average of 2.7 × 10-4% of total fluorine content, whereas the EOF was under the LOD in all of the measured samples. This result highlights the complexity of the accurate determination of PFAS compounds, displaying what kind of information the chosen methods provide.

Fluorine mass balance analysis in wild boar organs from the Bohemian Forest National Park.

Wild boars have been reported as bioindicators for per- and polyfluoroalkyl substances (PFAS) in a variety of studies. However, data about PFAS levels in wild boars from sites with limited industrial and general human activity is scarce. In this study, wild boar (Sus scrofa) organs from the Bohemian Forest National Park (Czech Republic) were used as bioindicators for PFAS pollution. In this work, 29 livers and 24 kidneys from 30 wild boars (0.5-5 years) were investigated using a fluorine mass balance approach. For this, the samples were measured using high performance liquid chromatography with electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS), targeting 30 PFAS, including legacy and replacement PFAS, direct total oxidisable precursor assay (dTOPA) and combustion ion chromatography (CIC). Perfluorocarboxylic acids (PFCAs) from C7 to C14 and perfluorooctanesulfonic acid (PFOS) were detected in >50 % of samples. In the livers, PFCAs dominated the profile with median concentrations of 230 µg/kg for perfluorononanoic acid (PFNA) and 75 µg/kg perfluorooctanoic acid (PFOA). PFOA and PFNA concentrations in the livers were one order of magnitude higher than in livers from wild boars caught in rural NE Germany considered as background concentration. PFOS in liver contributed only 30 % to the Σc(PFASTarget) with a median concentration of 170 µg/kg. Kidneys and livers contain an average of 2460 µg F/kg and 6800 µg F/kg extractable organic fluorine (EOF) respectively. Σc(PFASTarget) add up to a maximum of 10 % of the extractable organic fluorine. After oxidisation of the samples, PFOA, PFNA and Σc(PFASdTOPA) increased in livers, but could not explain the EOF. The elevated concentration of PFOA and PFNA may indicate differences in biomagnification for different habitats or an unidentified PFAS source in proximity to the national park.

Fluoride and acid enrichment in coal fire sponges in the Wuda coalfield, Inner Mongolia, Northern China.

Coal fire sponges (CFSs) are a type of sponge-like contaminated soil bulge common in coal fire areas. However, the impacts of CFSs on the local environment are not yet understood. Thus, this study investigated soil samples from CFSs in the Wuda coalfield, Inner Mongolia, China, focusing on the acidity, sulfate, and fluorine content. The results showed that the CFSs were highly acidic, with an average pH of 0.76, and contained high levels of SO42- (257.29 × 103 µg/g), total fluorine (TF, 2011.6 µg/g), and water-soluble fluorine (WF, 118.94 µg/g), significantly exceeding those in the regional background soil and indicating that CFSs are a point source of heavy pollution. Soils in the 8000 m2 reclamation zone showed elevated acidity and high SO42- (129.6 × 103 µg/g), TF (1237.8 µg/g), and WF (43.05 µg/g) levels, which was likely the result of the weathering and dissemination of CFS. The CFS samples were rich in hydrogen fluoride, releasing 202.05 ppb of it when heated to 40 °C. Correlation analysis indicated that the acid sulfate soils in CFSs are likely caused by HSO4-/SO42-. Time-of-flight secondary ion mass spectrometry detected four characteristic ions (F-, H3O+, H2SO4+, and HSO4-) in all micro-domains of each sample, indicating that ionic fluorine compounds and sulfuric acid hydrate were found in the CFS samples. Sulfate minerals detected in CFSs included CaSO4, Fe2(SO4)3, CdSO4, NH4HSO4, and Na2SO4. Thus, the results identified CFSs as a transmission channel for contamination, with erosional surface soils as the carrier, for the first time. CFSs pose a serious threat of contamination, albeit over limited areas.

Identification and quantification of fluorinated polymers in consumer products by combustion ion chromatography and pyrolysis-gas chromatography-mass spectrometry.

Total fluorine was determined in 45 consumer product samples from the Swedish market which were either suspected or known to contain fluorinated polymers. Product categories included cookware (70-550 000 ppm F), textiles (10-1600 ppm F), electronics (20-2100 ppm F), and personal care products (10-630 000 ppm F). To confirm that the fluorine was organic in nature, and deduce structure, a qualitative pyrolysis-gas chromatography-mass spectrometry (pyr-GC/MS) method was validated using a suite of reference materials. When applied to samples with unknown PFAS content, the method was successful at identifying polytetrafluoroethylene (PTFE) in cookware, dental products, and electronics at concentrations as low as 0.1-0.2 wt%. It was also possible to distinguish between 3 different side-chain fluorinated polymers in textiles. Several products appeared to contain high levels of inorganic fluorine. This is one of the few studies to quantify fluorine in a wide range of consumer plastics and provides important data on the concentration of fluorine in materials which may be intended for recycling, along with insights into the application of pyr-GC/MS for structural elucidation of fluorinated polymers in consumer products.

Analysis of the distribution across media, migration, and related driving factors of fluoride in cold and arid lakes during the freezing period.

Fluoride pollution in water has become a global challenge. This challenge especially affects China as a country experiencing serious fluoride pollution. While the have been past studies on the spatial distribution of fluoride, there has been less attention on different forms of fluoride. This study collected 176 samples (60, 40, and 76 ice, water, and sediment samples, respectively) from Lake Ulansuhai during the freezing period. The occurrence and spatial distribution characteristics of fluoride in lake ice-water-sediment were explored using Kriging interpolation, Piper three-line diagram, and Gibbs diagram analysis methods. The migration and transformation of fluoride during the freezing period were revealed and the factors influencing fluoride concentration in the water body were discussed considering the hydrochemical characteristics of lake surface water. The results showed that the average fluoride concentrations in the upper ice, middle ice and lower ice were 0.18, 0.09, and 0.12 mg/L, respectively, decreasing from north to south in the lake. The average concentrations of fluoride in surface water and bottom water were 0.63 and 0.83 mg/L, respectively. The concentrations of fluoride in ice and water were within the World Health Organisation drinking water threshold of 1.50 mg/L and the Class III Chinese surface water standard (GB3838-2002). The average sediment total fluorine was 1344.38 ± 200 mg/kg, significantly exceeding the global average (321 mg/kg) and decreasing with depth. The contents of water soluble, exchangeable, Fe/Mn bound, organic bound, and residual fluorides were 40.22-47.18, 13.24-43.23, 49.52-160.48, and 71.59-173.03 mg/kg, respectively. There was a significant positive correlation between fluoride concentration in ice and that in water. The change in fluoride concentration in water was mainly due to specific climatic and geographical conditions, pH, hydrochemical characteristics and ice sealing. This study is of great significance for the management of high-fluorine lakes in arid and semi-arid areas.

Interlaboratory Comparison of Extractable Organofluorine Measurements in Groundwater and Eel (Anguilla rostrata): Recommendations for Methods Standardization.

Research on per- and polyfluoroalkyl substances (PFAS) frequently incorporates organofluorine measurements, particularly because they could support a class-based approach to regulation. However, standardized methods for organofluorine analysis in a broad suite of matrices are currently unavailable, including a method for extractable organofluorine (EOF) measured using combustion ion chromatography (CIC). Here, we report the results of an international interlaboratory comparison. Seven laboratories representing academia, government, and the private sector measured paired EOF and PFAS concentrations in groundwater and eel (Anguilla rostrata) from a site contaminated by aqueous film-forming foam. Among all laboratories, targeted PFAS could not explain all EOF in groundwater but accounted for most EOF in eel. EOF results from all laboratories for at least one replicate extract fell within one standard deviation of the interlaboratory mean for groundwater and five out of seven laboratories for eel. PFAS spike mixture recoveries for EOF measurements in groundwater and eel were close to the criterion (±30%) for standardized targeted PFAS methods. Instrumental operation of the CIC such as replicate sample injections was a major source of measurement uncertainty. Blank contamination and incomplete inorganic fluorine removal may introduce additional uncertainties. To elucidate the presence of unknown organofluorine using paired EOF and PFAS measurements, we recommend that analysts carefully consider confounding methodological uncertainties such as differences in precision between measurements, data processing steps such as blank subtraction and replicate analyses, and the relative recoveries of PFAS and other fluorine compounds.

Diversity and negative effect of PM0.3-10.0 adsorbed by needles of urban trees in Irkutsk, Russia.

The study was performed in natural forests preserved within the Boreal zone city, Irkutsk, Russia. Test sites were selected in the forests in different districts of the city, where samples of Scots pine (Pinus sylvestris L.) and Siberian larch (Larix sibirica Ledeb.) needles were taken to study the adsorption on their surface of aerosol particles of different sizes, in microns: PM0.3, PM0.5, PM1, PM2.5, PM5, PM10. Scanning electron microscopy was used to obtain high-resolution photographs (magnification 800- × 2000, × 16,000) and aerosol particles (particulate matter-PM) were shown to be intensively adsorbed by the surface of needles, with both size and shape of the particles characterized by a wide variety. Pine needles can be covered with particles of solid aerosol by 50-75%, stomata are often completely blocked. Larch needles often show areas, which are completely covered with aerosol particles, there are often found stomata deformed by the penetration of PMx. X-ray spectral microanalysis showed differences in the chemical composition of adsorbed PMx, the particles can be metallic if metals predominate in their composition, carbonaceous-in case of carbon predominance-or polyelemental if the composition is complex and includes significant quantities of other elements besides metals and carbon (calcium, magnesium, potassium, sodium, sulfur, chlorine, fluorine). Since the particles contain a large proportion of technogenic pollutants, accumulation by the needles of some widespread pollutants was investigated. A direct correlation of a highly significant level between the concentration of PMx in the air and the accumulation of many heavy metals in pine and larch needles, as well as sulfur, fluorine, and chlorine, has been revealed, which indicates a high cleaning capacity of urban forests. At the same time, the negative impact of PMx particles on the vital status of trees is great, which shows in intense disturbance of the parameters of photosynthesis and transpiration, leading to a significant decrease in the growth characteristics of trees and reduction in the photosynthetic volume of the crowns. We consider that the results obtained are instrumental in developing an approach to improvement of urban forests status and creating a comfortable urban environment for the population.

Identifying Unknown Fluorine-Containing Compounds in Environmental Samples Using 19F NMR and Spectral Database Matching.

The ubiquity of per- and polyfluorinated alkyl substances (PFAS) in the environment is a continuing concern. While typical analytical methods for the analysis of PFAS include both targeted and non-targeted mass spectrometry, there remains a significant portion of fluorinated compounds that are not accounted for by these routine methods. It has been previously demonstrated that 19F NMR can be used to identify these compounds, helping to close the mass balance on total fluorine in the environment. 19F NMR offers an unbiased method of analysis that requires no anticipation of fluorine-carbon bonds or functional groups. However, there is resistance to further uptake of NMR spectroscopy as an analytical tool, owing to perceived difficulties in sensitivity and spectral overlap. In this study, we measure the 19F NMR spectrum of hundreds of fluorinated compounds and use this constructed database to determine the concentration of PFAS in an extracted sample of a known aqueous firefighting foam-contaminated site. The 19F NMR database has been included for use by other researchers, and we discuss the intricacies of 19F NMR as applied to environmental samples.

Distribution, enrichment mechanisms, and health risk assessment of high-fluorine groundwater in the Yudong Plain, Henan Province, China.

The Yudong Plain is in the eastern part of Henan Province, China, where there is little rain and high evaporation. Compared to other areas in Henan Province, the groundwater fluorine content is generally high, which affects the health of residents. Based on the systematic analysis of water chemistry data of shallow and mid-depth groundwater samples in the Yudong Plain, the causes of shallow and mid-depth high-fluorine groundwater in the Yudong Plain were explored using mathematical statistics, spatial interpolation, and ion ratios. The results show that the fluorine contents of both shallow and mid-depth groundwater in the study area are high. The shallow samples had fluorine contents ranging from 0.1 to 4.89 mg/L, with an exceedance rate of 48% and an average content of 1.15 mg/L. The fluorine content of mid-depth samples ranged from 0.14 to 3.32 mg/L, with an exceedance rate of 68% and an average content of 1.33 mg/L. The shallow high-fluorine groundwater is mainly distributed in the central low-lying area, and its main hydrochemical type is HCO3-Na·Mg; the mid-depth high-fluorine groundwater is mainly distributed in strips in the north and east of the study area, and its main water chemistry type is HCO3-Na. Fluorine enrichment in shallow groundwater in the study area is controlled by rock weathering, evaporation concentration, and competitive adsorption, while leaching and dissolution of fluorine-containing minerals in sedimentary strata are the main factors influencing fluorine enrichment in mid-depth groundwater. The results of the human health risk assessment (HRA) showed that the mean non-carcinogenic hazard quotients (HQs) in shallow groundwater were 0.95, 0.64, 0.57, and 0.55 for infants, children, teenagers, and adults, respectively, while the mean non-carcinogenic HQs in mid-depth groundwater were 1.11, 0.74, 0.66, and 0.63, respectively. The study provides a scientific basis for the rational development and use of groundwater in the area and offers theoretical support for the prevention and control of groundwater pollution.

Improved total organic fluorine methods for more comprehensive measurement of PFAS in industrial wastewater, river water, and air.

Per- and polyfluoroalkyl substances (PFAS) are high-profile environmental contaminants, many having long persistence in the environment and widespread presence in humans and wildlife. Following phase-out of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in North America and restrictions in Europe, PFAS replacements are now widely found in the environment. While liquid chromatography (LC)-mass spectrometry (MS) is typically used for measurement, much of the PFAS is missed. To more comprehensively capture organic fluorine, we developed sensitive and robust methods using activated carbon adsorption, solid phase extraction, and combustion ion chromatography (CIC) to measure total organic fluorine (TOF) in industrial wastewaters, river water, and air. Two extraction techniques, adsorbable organic fluorine (AOF) and extractable organic fluorine (EOF), were optimized and compared using 39 different PFAS, including replacements, such as GenX and perfluorobutanesulfonate. Our AOF method achieves 46-112% and 87% recovery for individual PFAS and PFAS mixtures, respectively, with 0.5 µg/L limit of detection (LOD) for a 50 mL sample volume and a 0.3 µg/L LOD for a 500 mL sample volume . Our EOF method achieves 72-99% and 91% recovery for individual PFAS and PFAS mixtures, respectively, with 0.2 µg/L LOD for a 500 mL sample volume and 0.1 µg/L LOD for 1200 mL. In addition to 39 anionic PFAS, two zwitterionic PFAS and two neutral PFAS were evaluated using the optimized TOF methods. Substantially higher TOF values were measured in industrial wastewater, river water, and air samples compared to LC-MS/MS, demonstrating how TOF methods provided a more comprehensive measurement of the total PFAS present, capturing known and unknown organic fluorine.

Influence of interflow carbonate-clay association for groundwater fluoride contamination in eastern Deccan, central India.

In central India, fluoride contamination in deeper basaltic aquifer is geogenic. This study demonstrates the source of fluorine enrichment in aquifer matrix and its release mechanism into groundwater. Magmatic-hydrothermal residual melt, i.e., albitic-calcic-amphibole-apatite-rich intrusive rock is the main source of fluorine enrichment. The association of this rock with interflow carbonate-clay assemblage played a significant role for fluoride contamination. Fluorine-enriched residual melt interacted with interflow carbonate-clay association, and this interaction metasomatized the carbonates and enhanced fluorine concentration in sediments. Bulk fluorine concentration of 988 ppm is measured in the soil developed over the association of intrusive rock and carbonate-clay assemblage. X-ray diffraction and electron-probe micro analysis confirmed the presence of fluorine-bearing and/or containing minerals, i.e., fluorite, fluorapatite, and palygorskite. The presence of bicarbonate and Na+ (from albitic feldspar) in alkaline water enhanced desorption of fluoride from clays, and dissociation from fluorapatite and fluorite from carbonate-clay assemblage, which released fluoride from aquifer matrix to groundwater. Clay horizon acts as an impervious cap on the deeper aquifer and increases the residence time of groundwater. In such favorable physico-chemical condition, fluoride released from aquifer matrix to groundwater and gradually increasing the degree of fluoride contamination.

An Analytical Protocol for the Differentiation and the Potentiometric Determination of Fluorine-Containing Fractions in Bovine Milk.

Free fluoride ions are effective in combating caries in children, and their supplementation in milk has been widely used worldwide for this purpose. Furthermore, it is known that ionic fluoride added to milk is distributed among its components, but little is known about their quantitative relationships. This is likely due to the absence of an analytical protocol aimed at differentiating and quantifying the most important forms of fluorine present in milk. For the first time, a comprehensive protocol made up of six potentiometric methods devoted to quantifying the most important fractions of fluorine in milk (i.e., the free inorganic fluoride, the inorganic bonded fluorine, the caseins-bonded fluorine, the whey-bonded fluorine, the lipid-bonded fluorine, and the total fluorine) has been developed and tested on real samples. Four of the six methods of the procedure are original, and all have been validated in terms of limit of detection and quantification, precision, and trueness. The data obtained show that 9% of all fluorine was in ionic form, while 66.3% of total fluorine was bound to proteins and lipids, therefore unavailable for human absorption. Beyond applications in dental research, this protocol could be extended also to other foods, or used in environmental monitoring.

Targeted PFAS analyses and extractable organofluorine - Enhancing our understanding of the presence of unknown PFAS in Norwegian wildlife.

With the current possible presence of thousands of PFAS compounds in industrial emissions, there is an increasing need to assess the impacts of PFAS regulation of conventional PFAS on one hand and the exposure to emerging and yet unknown PFAS on the other. Today's analytical methodologies using targeted approaches are not sufficient to determine the complete suite of PFAS present. To evaluate the presence of unknown PFAS, we investigated in this study the occurrence of an extended range of target PFAS in various species from the marine and terrestrial Norwegian environment, in relation to the extractable organofluorine (EOF), which yields the total amount of organofluorine. The results showed a varying presence of extractable fluorinated organics, with glaucous gull eggs, otter liver and polar bear plasma showing the highest EOF and a high abundance of PFAS as well. The targeted PFAS measurements explained 1% of the organofluorine for moose liver as the lowest and 94% for otter liver as the highest. PFCAs like trifluoroacetic acid (TFA, reported semi-quantitatively), played a major role in explaining the organic fluorine present. Emerging PFAS as the perfluoroethylcyclohexane sulfonate (PFECHS), was found in polar bear plasma in quantifiable amounts for the first time, confirming earlier detection in arctic species far removed from emission sources. To enable a complete organic fluorine mass balance in wildlife, new approaches are needed, to uncover the presence of new emerging PFAS as cyclic- or ether PFAS together with chlorinated PFAS as well as fluorinated organic pesticides and pharmaceuticals.

Spatial distribution characteristics and prediction of fluorine concentration in groundwater based on driving factors analysis.

Excess fluoride (F-) in groundwater can be hazardous to human health. A total of 360 ground water samples was collected from northern Anhui, China, to study the levels, distribution, and source of F-. And on this basis, predicting the spatial distribution of F- in a wider scale space. The range of F- was 0.1-5.8 mg/L, with a mean value of 1.2 mg/L, and 26.4 % of the samples exceeded the acceptable level of 1.5 mg/L. Moreover, the water-rock interaction (fluorite dissolution) and cation alternate adsorption were considered to be two main driving factors of high F- in groundwater. To further illustrate the spatial effects, the BME-RF model was established by combining the main environmental factors. The spatial distribution of F- was quantitatively predicted, and the response to environmental variables was analyzed. The R2 of BME-RF model reached 0.93, the prediction results showed that the region with 1.0-1.5 mg/L of F- accounts for 47.2 % of the total area. The predicted F- content of nearly 70 % of groundwater in this area has exceeded 1.0 mg/L, which was dominated by Na+ and HCO3- type. The spatial variability of F- in the study area was mainly affected by hydrogeological conditions, and the vertical distribution characteristics were related to the spatial variation of slope, distance from runoff, and hydrochemical types. The results of the study provide new insights into the F- concentration prediction in underground environment, especially in the borehole gap area.

AFFECTION ON CARIES AND ITS COMPLICATIONS OF TEMPORARY TEETH OF CHILDREN IN A REGION WITH EXCESS FLUORINE CONTENT IN DRINKING WATER.

OBJECTIVE: Aim: The aim of the study was to determine the indicators of caries and its complications in the temporary teeth of children who permanently live in a region with a high fluoride content in drinking water. PATIENTS AND METHODS: Materials and Methods: It was examined with the definition of caries and its complications 277 children in the age range from 2 to 13 years, who were born and permanently live in the urban-type settlement of Mashivka. The fluoride content in the drinking water of the settlement was 1.7-2.5 mg/l. RESULTS: Results: During the analysis of data from the survey of children who were born and permanently lived in the urban-type settlement of Mashivka, it was determined that the prevalence of caries of temporary teeth probably increases with age. Half of the 3-5-year-old children had caries-affected teeth, and temporary tooth caries reached the highest rates in 10-year-old children. It should be noted that a fifth of children in the youngest age group (3-5 years old) suffer from pulpitis and periodontitis of temporary teeth. CONCLUSION: Conclusions: The conducted examination of children urban-type settlement of Mashivka confirms the opinion that the excessive content of fluorine in drinking water does not have a caries-protective effect, and the intensity of the process reaches the indicators characteristic of regions with its optimal content. Such a situation requires strengthening measures for both primary and secondary prevention of dental diseases.

Paints: A Source of Volatile PFAS in Air─Potential Implications for Inhalation Exposure.

Paints are widely used in indoor settings yet there are no data for volatile per- and polyfluoroalkyl substances (PFAS) for paints or knowledge if paints are potentially important sources of human exposure to PFAS. Different commercial paints (n = 27) were collected from local hardware stores and analyzed for volatile PFAS by gas chromatography-mass spectrometry (GC-MS), nonvolatile PFAS by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-qTOF), and total fluorine by 19F nuclear magnetic resonance spectroscopy (NMR). Diluted paint required clean up to remove 6:2 fluorotelomer phosphate diester (diPAP), which thermally transforms into 6:2 FTOH at 280 °C (GC inlet temperature). Only 6:2 FTOH (0.9-83 µg/g) and 6:2 diPAP (0.073-58 µg/g) were found in five exterior and nine interior paints and only accounted for a maximum of 17% of total fluorine. Upon drying, 40% of the FTOH mass was lost, and the loss was verified by measurements of the cumulative FTOH mass measured in the air of a small, confined space over a 3 h period. Based on the liquid paint results, the ConsExpo model was used for potential exposure assessment and one commercial paint exceeded the chosen reference dose (5 µg/kg-day) for children and adults, indicating the potential for human exposure during painting.