Single injection by LC-ESI-MS/MS for simultaneous determination of organophosphate tri- and di-esters in plant tissue based on ultrasonic-assisted sequential extraction and single-step purification.

A novel methodology based on ultrasonic-assisted sequential extraction, dispersive-SPE purification, and single-injection on liquid chromatography-tandem mass spectrometry (LC-MS/MS) is proposed, for the first time, to simultaneously measure 14 tri-OPEs and 9 di-OPEs in plant tissues. The samples were successively ultrasonicated with a mixture of hexane:dichloromethane (1:1, v/v) and 8% acetic acid in acetonitrile for extracting tri- and di-OPEs purified with graphitized carbon black and quantitated on LC-MS/MS at the same time. The recoveries of targeted tri- and di-OPEs in the matrix spike ranged from 66% to 120% and 71% to 110% respectively. The proposed method was validated by processing eight types of common vegetables including spinach (Spinacia oleracea L.), lettuce (Lactuca sativa), carrot (Daucus carota var. sativa Hoffm.), sweet potato (Solanum tuberosum L.), cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), green beans (Phaseolus vulgaris), and cowpeas (Vigna unguiculata), with the recoveries of surrogates ranging from 84% to 98%.

Analysis and subcellular distribution of organophosphate esters (OPEs) in rice tissues.

Recent studies have identified the ability of plants to uptake and translocate organophosphate esters (OPEs) within cells. In response to the increasing interest in OPEs and their occurrence in paddy fields and rice, the current study aimed to present an effective and sensitive GC-MS based methodology for quantitative determination of 11 OPEs with octanol-water coefficients ranging from 1.6 to 10. Rice was sonicated with hexane and dichloromethane, and fractionated on two columns: one consisting of neutral alumina, and neutral silica, and the other consisting of graphitized carbon black. Method precision was validated using spiked rice (n = 30) and procedural blanks (n = 9). The mean recovery of matrix spikes for all target OPEs were within 78-110% with relative standard deviation lower than 25%, with a few exceptions. This method was applied to process the wild rice (O. sativa) in which tri-n-propyl phosphate was the dominant targeted OPE. The recoveries of surrogate standards were 81 ± 17% for d12- tris(2-chloroethyl) phosphate and 95 ± 8.8% for 13C12- triphenyl phosphate. The developed method was further used to examine the recoveries of target OPEs in the subcellular structure of rice tissues, including cell wall, cell organelles, cell water-soluble fractions, and cell residue. Recoveries of most target OPEs were in the range of 50-150%; however, ion enhancement was observed for four OPEs in root and shoot tissues. Hydrophobic OPEs accumulated in the cell wall, cell residue, and cell organelles while chlorinated OPEs mainly distributed in the cell water-soluble fraction. These results provide new insight for the ecological risk assessment of OPEs in an important food staple.

Associations between faecal chemical pollutants and hormones in primates inhabiting Kibale National Park, Uganda.

While anthropogenic pollutants are known to be a threat to primates, our understanding of exposure to pollutants in situ and their sub-lethal effects is still limited. We used non-invasive biomonitoring to examine associations between faecal concentrations of 97 chemical pollutants and faecal hormone metabolites of cortisol and oestradiol in four primate species inhabiting Kibale National Park, Uganda (chimpanzees-Pan troglodytes, olive baboons-Papio anubis, red colobus-Piliocolobus tephrosceles and red-tailed monkeys-Cercopithecus ascanius). Across all species (n = 71 samples), results demonstrated positive associations of organochlorine pesticides (OCPs) (ß = 0.143, p = 0.020) and organophosphate esters (ß = 0.112, p = 0.003) with cortisol in adult females. Additionally, we observed positive associations of OCPs (ß = 0.192, p = 0.013) and brominated flame retardants (ß = 0.176, p = 0.004) with cortisol in juveniles. Results suggest that cumulative pesticides and flame retardants are disruptive to endocrine function in these populations, which could have implications for development, metabolism and reproduction. Our study further demonstrates that faeces can be an important, non-invasive matrix for examining pollutant-hormone associations in wild primates and other critical wildlife populations.

Determination of polyoxymethylene-water partition coefficients for diverse organophosphate esters (OPEs) and prediction of the free-dissolved OPEs in OPE-contaminated soil.

Increasing attention on the estimation of bioavailability of organophosphate esters (OPEs) in soil or sediment has urged the development of techniques to measure soil-/sediment-associated porewater concentrations of OPEs. In this study, we investigated the sorption dynamics of 8 OPEs to polyoxymethylene (POM) spanning one order of magnitude of aqueous OPE concentrations and proposed POM-water partitioning coefficients (Kpom/w) for OPEs. The results showed that the Kpom/w values were mainly affected by the hydrophobicity of OPEs. OPEs with high solubility preferentially partitioned into the aqueous phase indicated by the low log Kpom/w values; while lipophilic OPEs were observed to be taken up by POM. The concentration of lipophilic OPEs in the aqueous phase had a strong impact on their sorption dynamics on POM, with higher aqueous concentrations accelerating the sorption dynamics and shortening the time for equilibration. We proposed that the required time to reach equilibration for targeted OPEs should be 42 d. The proposed equilibration time and Kpom/w values were further validated by applying POM to soil artificially contaminated with OPEs to measure OPEs soil-water partitioning coefficients (Ks). The variations of Ks among soil types implied the need to elucidate the effects of soil properties and chemical properties of OPEs on their distribution between soil and water in the future.

The human and ecological risks of neonicotinoid insecticides in soils of an agricultural zone within the Pearl River Delta, South China.

Neonicotinoid insecticides (NIIs) are extensively used worldwide and frequently detected in the environment. The human and ecological risks associated with the occurrence of NIIs in agricultural zones are of high importance. The present study highlights the regional occurrence and human exposure risks of NIIs in agricultural soil within the Pearl River Delta (PRD), South China. Six neonicotinoids, i.e., imidacloprid, clothianidin, acetamiprid, imidaclothiz, dinotefuran, and flonicamid, were measured in 351 soil samples from Zengcheng, a typical agricultural zone. The soil samples were categorized into three groups based on cultivated plants: vegetables, rice, and fruits. At least one of these neonicotinoid insecticides was detected in 95% of the soil samples. The levels of ∑6NII (range (median)) were 0.26-390 (23), 0.26-280 (6.1), and 0.26-120 (5.0) ng g-1 dry weight in soil samples from vegetable farms, rice paddies, and fruit farms, respectively. Neonicotinoids were detected more frequently and at statistically higher concentrations in vegetable farms than in both rice paddies and fruit farms. This is likely ascribed to higher application frequencies of NIIs in vegetable farms due to higher planting frequencies. The hazard index values for human exposure to NIIs in the agricultural soils were all below 1, suggesting negligible non-cancer risks. The current residual levels of NIIs in the soils could however pose sub-lethal or acute effects to non-target terrestrial organisms such as earthworms. The present study suggests that more information is needed regarding NIIs contamination in soils from agricultural regions of South China to ensure that human and ecological risk from exposure to these compounds can be fully addressed.

Uptake and translocation of organophosphate esters by plants: Impacts of chemical structure, plant cultivar and copper.

Organophosphate esters (OPEs) are normally used as flame retardants, plasticizers and lubricants, but have become environmental pollutants. Because OPEs are normally present alongside heavy metals in soils, the effects of interactions between OPEs and heavy metals on plant uptake of OPEs need to be determined. In this study, we investigated the effects of OPEs chemical structure, plant cultivar and copper (Cu) on the uptake and translocation of OPEs by plants. The bioaccumulation of OPEs varied among plant cultivars. They were preferentially enriched in carrot, with the lowest concentrations observed in maize. OPEs with electron-ring substituents (ER-OPEs) exhibited a higher potential for root uptake than did OPEs with open-chain substituents (OC-OPEs), which could be attributed to the higher sorption of ER-OPEs onto root charged surfaces. This was explained by the stronger noncovalent interactions with the electron-rich structure of ER-OPEs. The presence of Cu slightly reduced the distinct difference in the ability of roots to take up OC-OPEs and ER-OPEs. This was explained by the interactions of Cu ions with the electron-rich structure of ER-OPEs, which suppressed the sorption of ER-OPEs on the root surface. A negative relationship between the logarithms of the translocation factor and octanol-water partition coefficient (Kow) was observed in treatments with either OPEs only or OPEs + Cu, implying the significant role of hydrophobicity in the OPEs acropetal translocation. The results will improve our understanding of the uptake and translocation of OPEs by plant cultivars as well as how the process is affected by the chemical structure of OPEs and Cu, leading to improvements in the ecological risk assessment of OPEs in the food chain.

The effect of Fenton reaction using H2O2 and water control on the distribution and accumulation of As speciation within the soil-rice system.

The behavior of arsenic (As) in paddy soil is of great interest because rice is an efficient As accumulator, which can result in potential health risks to humans. In this study, we investigated the distribution and translocation of As speciation within the soil-rice system in the presence of Fenton solution (100 µM H2O2 and 100 µM Fe2+). The results showed that the iron plaque concentrations were enhanced either by the addition of Fenton solution or under flooded condition. In addition, total As, As5+, and As3+ concentrations were lower in rice tissues treated with Fenton solution than those without Fenton solution treatments. Therefore the addition of Fenton solution can reduce As speciation accumulation in rice tissue. This study revealed the function of Fenton solution on the fate of As speciation distribution within soil-rice system and the link between iron plaque and As accumulation in rice tissue under flooded and non-flooded conditions.

Occurrence, Spatial, and Seasonal Variations, and Gas-Particle Partitioning of Atmospheric Current-Use Pesticides (CUPs) in the Great Lakes Basin.

There is very little information on the gas-particle partition and spatial and seasonal variations of current-use pesticides (CUPs) in the Great Lakes basin. The atmospheric concentrations of 36 CUPs were measured in 24 h gas and particle samples collected in 2017 at six sites in the Great Lakes basin. Thirteen individual CUPs were detected at least once in both gas- and particle-phase samples, with chlorothalonil, trifluralin, metolachlor, λ-cyhalothrin, cypermethrin, and chlorpyrifos detected in >50% samples. The gas-particle partitioning analysis suggests that gas-phase chemicals like trifluralin and chlorpyrifos were not influenced by either temperature or relative humidity while particle-phase chemicals like metolachlor were marginally and negatively correlated with relative humidity. Median total CUP concentrations were 339, 238, 84, 33, 60, and 6.0 pg/m3 at Chicago, Cleveland, Sturgeon Point, Point Petre, Sleeping Bear Dunes, and Eagle Harbor, respectively. The concentrations of total CUPs and most individual CUPs were generally higher at the urban sites of Chicago and Cleveland than at the rural/remote sites of Sturgeon Point, Point Petre, Sleeping Bear Dunes, and Eagle Harbor. Chlorothalonil, trifluralin, bifenthrin, and chlorpyrifos were the most abundant individual CUPs among fungicides, herbicides, pyrethroid insecticides, and other insecticides, respectively. The spatio-seasonal variation suggests that fungicides at Sturgeon Point and Sleeping Bear Dunes, with the highest fraction of agricultural land use, were associated with agricultural activities, while pyrethroid insecticides were generally driven by human activities.

Uptake, Acropetal Translocation, and Enantioselectivity of Perfluorooctane Sulfonate in Maize Coexisting with Copper.

Plant uptake and translocation of perfluorooctane sulfonate (PFOS) are critical for food safety and raise major concerns. However, those processes are associated with many undisclosed mechanisms, especially when PFOS coexist with heavy metals. In this study, we investigated the effect of copper (Cu) on PFOS distribution in maize tissues by assessing the PFOS concentration and enantioselectivity. The presence of <100 µmol/L Cu exerted a limited effect on PFOS bioaccumulation, while >100 µmol/L Cu damaged the root cell membrane and increased root permeability, resulting in a higher PFOS concentration in roots. The suppression of acropetal translocation might be attributed to Cu inhibition of carrier proteins. The enantiomer fraction (EF) of 1m-PFOS at <100 µmol/L Cu was higher than that in a commercial product (0.5). Racemic PFOS was detected at >100 µmol/L Cu in roots and the EF variation changed from positive to negative in shoots. These EF results evidenced the existence of a protein-mediated uptake pathway. Besides, this study indicated the challenge of chiral signature application in PFOS source identification, given the effects of heavy metals and plants on PFOS enantioselectivity. The findings provide insight into PFOS bioaccumulation in plants cocontaminated with Cu and will facilitate environmental risk assessment.

More restriction, more overeating: conflict monitoring ability is impaired by food-thought suppression among restrained eaters.

Numerous studies have shown that restrained eating is not an effective weight loss strategy. Restrained eaters often suppress their desires and thoughts about tasty food, which makes it more difficult to control themselves in subsequent eating behavior. The ego depletion impairs conflict monitoring abilities. Therefore, this study explored the effects of food thoughts suppression on restrained eaters' conflict monitoring. Therefore, this study used functional magnetic resonance imaging (fMRI) methods to explore changes in the activity of brain regions involved in conflict monitoring when restrained eaters choose between high- and low-calorie foods after either suppressing or not suppressing thoughts about food. The results showed that, compared to the control condition, after suppression of such thoughts, restrained eaters chose more high-calorie foods and displayed decreased activity in the dorsal anterior cingulate cortex-an important region in charge of conflict monitoring. At the same time, the functional coupling of the dorsal anterior cingulate cortex and the precuneus increased. Our findings suggest that restrained eaters' suppression of thoughts about tasty food could lead to a decline in their ability to monitor conflicts between current behaviors and goals, which in turn leads to unhealthy eating behavior.

Resting state differences between successful and unsuccessful restrained eaters.

Restrained eating is a popular weight loss strategy for young women that tends to have limited effectiveness over extended periods of time. Although previous studies have explored and identified possible personality and behavior differences between successful and unsuccessful restrained eaters (REs), there has been a paucity of research on neurophysiological differences.Towards addressing this gap, we assessed brain resting state (Rs) differences in groups of unsuccessful REs (N = 39) and successful REs (N = 31). In line with hypotheses, unsuccessful REs displayed reduced regional homogeneity in brain regions involved in cognitive control (inferior parietal lobe) compared to successful REs. Regions involved in conflict monitoring (anterior cingulate cortex) were also observed to be comparatively less active in the unsuccessful RE group. Finally, based on analyses of independent components and seed-based functional connectivity, regions involved in conflict monitoring and cognitive control, especially those localized within the frontoparietal network, showed weaker connectivities among unsuccessful REs compared to their successful counterparts.These results underscore specific brain Rs differences between successful REs and unsuccessful REs in regions implicated in cognitive control and conflict monitoring.

The use of silicone wristbands to evaluate personal exposure to semi-volatile organic chemicals (SVOCs) in France and Italy.

In this exploratory study, we measured for the first-time human exposure to about 90 semi-volatile organic chemicals (SVOCs) in France and Italy using silicone wristbands. Participants in France (n = 40) and in Italy (n = 31) wore a silicone wristband for five days during 2018 and 2019. Samples were analyzed for 39 polybrominated diphenyl ethers (PBDEs), 10 novel brominated flame retardants (nBFRs), 25 organophosphate esters (OPEs), and 18 polycyclic aromatic hydrocarbons (PAHs). In both groups, the most commonly detected chemicals were BDE-209, BEHTBP, tris[(2R)-1-chloro-2-propyl] phosphate (TCIPP), and phenanthrene among PBDEs, nBFRs, OPEs, and PAHs, respectively. The concentrations of ∑39 PBDEs, ∑10 nBFRs, ∑25 OPEs, ∑18 PAHs, and of most individual chemicals were generally significantly higher in samples from France than in those from Italy, except for BDE-209 and TCIPP. On a broader scale, the chemical concentrations were generally significantly lower in this study than those measured in the United States in previous studies using the same type of wristbands. Efforts to standardize the protocols for the use of silicone wristbands are still needed but this study shows that wristbands are capable of capturing regional differences in human exposure to a large variety of SVOCs and, therefore, can be used as personal exposure monitor for studies with global coverage.

Distribution and Chiral Signatures of Polychlorinated Biphenyls (PCBs) in Soils and Vegetables around an e-Waste Recycling Site.

The distribution and composition of polychlorinated biphenyls (PCBs) within soil-plant systems around a notorious e-waste recycling site were investigated. The average total PCB concentrations in rhizospheric soils (RSs) and nonrhizospheric soils (NRSs) were 2160 and 1270 pg g-1 dry weight (DW), respectively. PCBs were more enriched in RS than NRS for most vegetable species. PCB accumulation in plant tissues varied greatly among plant cultivars, ranging from 4020 to 14 500 pg g-1 DW in shoots and from 471 to 24 400 pg g-1 DW in roots. The compositions of PCBs in soil and plants showed that hexa- and hepta-chlorinated PCBs were preferentially accumulated in soils, while tri- and tetra-PCBs were abundant in plant tissues. These results indicated that low-chlorinated PCBs might be prone to accumulation and transfer within plants, which was confirmed by the relationship between the root concentration factor and octanol-water coefficient. The first eluting enantiomers of PCB 84 and PCB 95 were preferentially transferred between the soil and plants, while the stereoselectivity of PCB 136 varied among plant species. A significant difference in enantiomeric fractionation of PCB 84 between the soil and roots indicated that enantiomeric enhancement of PCB 84 occurred during its translocation from soil to root, whereas no such difference was observed in these chiral PCBs during their translocation from the root to the shoot.

Feces are Effective Biological Samples for Measuring Pesticides and Flame Retardants in Primates.

The habitats of wild primates are increasingly threatened by surrounding anthropogenic pressures, but little is known about primate exposure to frequently used chemicals. We applied a novel method to simultaneously measure 21 legacy pesticides (OCPs), 29 current use pesticides (CUPs), 47 halogenated flame retardants (HFRs), and 19 organophosphate flame retardants in feces from baboons in the U.S.A., howler monkeys in Costa Rica, and baboons, chimpanzees, red-tailed monkeys, and red colobus in Uganda. The most abundant chemicals were α-hexachlorocyclohexane (α-HCH), ß-hexachlorocyclohexane (ß-HCH), and hexachlorobenzene among OCPs across all sites, chlorpyrifos among CUPs in Costa Rica and Indiana, decabromodiphenylethane (DBDPE) in Costa Rica and Indiana and 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) in Uganda as HFRs, and tris(2-butoxyethyl) phosphate (TBOEP) as OPFRs across all sites. The detected chemical concentrations were generally higher in red-tailed monkeys and red colobus than in chimpanzees and baboons. Our methods can be used to examine the threat of chemical pollutants to wildlife, which is critical for endangered species where only noninvasive methods can be used.

Red for "Stop": "Traffic-Light" Nutrition Labels Decrease Unhealthy Food Choices by Increasing Activity and Connectivity in the Frontal Lobe.

Food labels comprise a national health-intervention policy that informs consumers of food-product nutritional value. Previous evidence has indicated that, compared to a purely numeric guideline-daily-amount label, a traffic-light-inspired, color-coded label more effectively conveys the nutritional level and increases the selection of healthier products. Therefore, we used functional magnetic resonance imaging to assess the mechanism whereby traffic-light and guideline-daily-amount labels influence food-related decision-making. Forty-four female dieters (age, mean = 20.0, standard deviation = 1.45 years) were recruited to participate in a food-choice task; healthy or unhealthy food options were presented with color-coded traffic-light or purely numeric guideline-daily-amount labels, and the participants were asked to state their preference. We found that, compared with the guideline-daily-amount label, a salient, red traffic-light label potentially reduced unhealthy food-related decision-making and activated the superior medial frontal gyrus and the supplementary motor area, which are implicated in the execution of responses and motor inhibition. For the same stimulus contrast, we also found increased activation in the anterior cingulate cortex, which is associated with salient information monitoring. Finally, we found stronger functional connectivity between the anterior cingulate cortex and inhibitory regions (inferior and middle frontal gyri) under red-traffic-light than under guideline-daily-amount label conditions. These results suggest that traffic-light-inspired labels may be a more effective means of public-policy intervention than are numeric labels conveying guideline daily amounts.

Association between Thyroid Function and Exposures to Brominated and Organophosphate Flame Retardants in Rural Central Appalachia.

Exposure to flame retardants (FRs) is associated with adverse effects on human health. Focusing on three FR groups, including polybrominated diphenyl ethers (PBDEs), organophosphate FRs (OPFRs), and novel brominated FRs (nBFRs), we determined the levels of these chemicals in indoor air in homes in rural Central Appalachia using passive air samplers and personal exposures in the residents of these homes using silicone wristbands. We also investigated the relationships between the FR levels in wristbands and the thyroid function. The median total concentrations of PBDEs, OPFRs, and nBFRs were 210, 25 000, and 69 pg/m3 in indoor air, and 49, 670, and 110 ng/g in wristbands, respectively. The most abundant chemicals in both air and wristbands were BDE-47 and -99 among PBDEs, tris[(2R)-1-chloro-2-propyl] phosphate among OPFRs, and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and bis(2-ethylhexyl) tetrabromophthalate among nBFRs. In gender-specific regression models that were controlled for age and smoking, significant associations were observed between BDE-99, BDE-197, and 2-ethylhexyldiphenyl phosphate (EHDP) and free thyroxine (FT4), between BDE-100 and free triiodothyronine (FT3), and between anti-Dechlorane Plus (DP) and thyroid-stimulating hormone (TSH). In particular, most penta-BDE congeners were significantly or marginally significantly associated with FT4 and FT3 for both females and males. Our results suggest that wristbands can be used as suitable exposure monitors for evaluating human exposure to FRs.

Personal exposure to polycyclic aromatic hydrocarbons in Appalachian mining communities.

Coal mining activities may increase residential exposure to polycyclic aromatic hydrocarbons (PAHs), but personal PAH exposures have not been studied in mining areas. We used silicone wristbands as passive personal samplers to estimate PAH exposures in coal mining communities in Central Appalachia in the United States. Adults (N = 101) wore wristbands for one week; 51 resided in communities within approximately three miles of surface mining sites, and 50 resided 10 or more miles from mining sites. Passive indoor polyurethane foam (PUF) sampling was conducted in residents' homes, and a sample of 16 outdoor PUF samples were also collected. Nine PAH congeners were commonly detected in wristbands (mean ±â€¯standard deviation), including phenanthrene (50.2 ±â€¯68.7 ng/g), benz[a]anthracene (20.2 ±â€¯58.2 ng/g), fluoranthene (19.4 ±â€¯24.1 ng/g) and pyrene (15.2 ±â€¯18.2 ng/g). Controlling for participant characteristics and season, participants living closer to mining sites had significantly higher levels of phenanthrene, fluorene, fluoranthene, pyrene and ∑PAHs in wristbands compared to participants living farther from mining. Indoor air showed no significant group differences except for pyrene, but outdoor air showed significant or marginally significant differences for phenanthrene, fluorene, pyrene and ∑PAHs. The results suggest that mining community residents face exposure to outdoor mining-related pollutants, and demonstrate that personal silicone wristbands can be deployed as effective passive sampling devices.

Silicone wristbands integrate dermal and inhalation exposures to semi-volatile organic compounds (SVOCs).

Silicone wristbands are being increasingly used to assess human exposure to semi-volatile organic compounds (SVOCs). However, it is unclear what exposure pathways wristbands integrate. To test the hypothesis that wristbands integrate inhalation and dermal exposures, we measured 38 chemicals from four compound groups (PAHs, PBDEs, nBFRs, and OPEs) in silicone wristbands and brooches, active air samples (Occupational Safety and Health Administration Versatile Sampler or OVS cartridge), and hand wipes from 10 adults during a 72-hour period. Phenanthrene, BDE-47, 2­ethylhexyl 2,3,4,5­tetrabromobenzoate (EHTBB), tris[(2R)­1­chloro­2­propyl] phosphate (TCIPP), and tris(1,3­dichloro­2­propyl) phosphate (TDCIPP) were the predominant compounds in all four matrices. In a linear regression analysis, the compound levels in OVS were positively associated with those in wristbands and brooches for nBFRs and OPEs, but not for PAHs and PBDEs. The compound levels in wristbands were positively associated with those in hand wipes and brooches for all chemicals. The regressions between the levels in wristbands and OVS or brooches combined with the levels in hand wipes showed stronger, supporting the hypothesis that wristbands captured inhalation and dermal exposure pathways.

Atmospheric Occurrence of Legacy Pesticides, Current Use Pesticides, and Flame Retardants in and around Protected Areas in Costa Rica and Uganda.

Protected areas have developed alongside intensive changes in land use and human settlements in the neighboring landscape. Here, we investigated the occurrence of 21 organochlorine pesticides (OCPs), 14 current use pesticides (CUPs), 47 halogenated flame retardants (HFRs), and 19 organophosphate esters (OPEs) in air around Las Cruces (LC) and La Selva (LS) Biological Stations, Costa Rica, and Kibale National Park (KNP), Uganda using passive air samplers (PAS) with polyurethane foam (PUF) discs (PAS-PUF). Significantly higher concentrations of CUPs were observed around LS, while LC had a higher concentration of OCPs. Land use analysis indicated that LS had a higher fraction of agriculture than LC (33% vs 14%), suggesting the higher CUPs concentration at LS was related to pesticide intensive crops, while higher OCPs concentration at LC may be attributed to the area's long agricultural history characterized by small-scale subsistence farming or long-range transport. In Uganda, CUPs and OCPs were generally lower than in Costa Rica, but high concentrations of HFRs were observed inside KNP, possibly due to human activity at research camps near the protected forest. This is the first study that documented the occurrence of anthropogenic chemicals in the air at protected areas with tropical forests.

Analysis of brominated and chlorinated flame retardants, organophosphate esters, and polycyclic aromatic hydrocarbons in silicone wristbands used as personal passive samplers.

For the first time, we present an analytical method to simultaneously extract, fractionate, and quantify four groups of semi-volatile organic compounds (SVOCs) in silicone wristbands, including 35 polybrominated diphenyl ethers (PBDEs), 10 novel flame retardants (NFRs), 19 organophosphate esters (OPEs), and 13 polycyclic aromatic hydrocarbons (PAHs). Wristbands were extracted using ultrasonication, and cleaned and fractionated on two multi-layer columns: one consisting of neutral alumina, neutral silica and Florisil, and the other consisting of neutral alumina, neutral silica, and acidic silica. Method accuracy and precision were validated using spiked wristband samples (n = 8) and procedural blanks (n = 7). Average matrix spike percent recoveries for all target analytes were within 57-107% with relative standard errors < 20%, with a few exceptions. This method was applied to analyze thirteen wristbands worn by ten participants for seven days; three participants wore two wristbands to evaluate duplicate samples. Percent recoveries of surrogate standards for all four groups of analytes in these wristbands were all within the 80-120% range with a few exceptions: recoveries for 13C12BDE-209 and for 13C12-triphenyl phosphate ranged from 35 to 62% and 69-176%, respectively. The majority of target analytes were detected in at least half of worn wristbands. The levels of total PBDEs, NFRs, OPEs and PAHs in deployed wristbands ranged from 28.4 to 412 ng, 40.7 to 625 ng, 2440 to 9580 ng, and 76.2 to 1240 ng, respectively.