Ultraviolet radiation exposure in cannabis-growing facilities.

Cannabis cultivation and processing is becoming an important industry in the United States and Canada. The industry employs over 400,000 workers in the United States and is growing rapidly. Both natural sunlight and artificial lamp-generated radiation are commonly used to grow cannabis plants. These optical sources can contain both visible and ultraviolet radiation (UVR) wavelengths, and overexposure to UVR is associated with negative health effects. The severity of these adverse health effects is governed by the specific wavelengths and exposed dose of UVR, yet worker exposure to UVR within cannabis-growing facilities has not been studied. In this study, worker exposure to UVR was assessed at five cannabis production facilities in Washington State, including indoor, outdoor, and shade house facilities. Lamp emission testing was performed at each facility and worker UVR exposures were measured for 87 work shifts. Observations of worker activities and use of personal protective equipment in association with UVR exposure measurements were recorded. For lamp emission measurements, at 3 feet from the center of the lamp, the average irradiances were 4.09 × 10-4, 6.95 × 10-8, 6.76 × 10-9, 3.96 × 10-9, and 1.98 × 10-9 effective W/cm2 for germicidal lamps, metal halide lamps, high-pressure sodium lamps, fluorescent lamps, and light emitting diodes, respectively. The average measured UVR exposure was 2.91 × 10-3 effective J/cm2 (range: 1.54 × 10-6, 1.57 × 10-2 effective J/cm2). Thirty percent of the work shifts monitored exceeded the American Conference for Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV®) of 0.003 effective J/cm2. Exposures were highest for workers who spent all or part of the work shift outdoors, and solar radiation was the primary source of worker UVR exposure for most of the work shifts that exceeded the TLVs. Outdoor workers can reduce UVR exposure by applying sunscreen and wearing appropriate personal protective equipment. Although the artificial lighting used in the cannabis production facilities included in this study did not contribute substantially to the measured UV exposures, in many cases the lamp emissions would generate theoretical exposures at 3 feet from the center of the lamp that would exceed the TLV. Therefore, employers should choose low UVR emitting lamps for indoor grow operations and should use engineering controls (e.g., door-interlocks to de-energize lamps) to prevent worker exposure to UVR from germicidal lamps.

Wearable Spectroradiometer for Dosimetry.

Available wearable dosimeters suffer from spectral mismatch during the measurement of broadband UV and visible radiation in environments that receive radiation from multiple sources emitting differing spectra. We observed this type of multi-spectra environment in all five Washington State cannabis farms visited during a field study investigating worker exposure to ultraviolet radiation in 2018. Spectroradiometers do not suffer from spectral mismatch in these environments, however, an extensive literature review conducted at the time of writing did not identify any spectroradiometers that were directly deployable as wearable dosimetry devices. To close this research gap, we developed a microcontroller system and platform that allows for researchers to mount and deploy the Ocean Insight Flame-S Spectroradiometer as a wearable device for measurement of UV and visible wavelengths (300 to 700 nm). The platform validation consisted of comparing measurements taken under platform control with measurements taken with the spectrometer controlled by a personal computer running the software provided by the spectroradiometer manufacturer. Three Mann-Whitney U-Tests (two-tailed, 95% CI), one for each intensity condition, compared the central tendency between the total spectral power (TSP), the integral of a spectrum measurement, measured under both control schemas. An additional analysis of per pixel agreement and overall platform stability was performed. The three Mann-Whitney tests returned no significant difference between the set of TSPs for each filter condition. These results suggest that the spectroradiometer takes measurements of equivalent accuracy under both control schemas, and can be deployed as a wearable device for the measurement of wavelength resolved UV and visible radiation.

Variability in hair gadolinium concentrations among decedents who received gadolinium-based contrast agents.

This study utilized laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify gadolinium in the hair of autopsy cases that had received gadolinium-based contrast agents (GBCAs) before death. Consecutive autopsy cases were reviewed for GBCA injections and subjects who received a single type of GBCA in the year before death were included. Hair samples were analyzed using LA-ICP-MS as a line scan technique and parameters were optimized to maximize instrument sensitivity, accuracy, and precision. Linear regression analyses between hair measures and gadolinium dose were executed. LA-ICP-MS analysis produced a time-resolved record of GCBA exposure, with the position of the gadolinium peak maxima along the hair shaft providing a good estimate for the day that GBCA injection occurred (R2 = 0.46; p = 0.0022); however, substantial within and between subject variation in the position of the GBCA peak was observed. Average area under the curve for gadolinium peaks in the hair samples was a better predictor of gadolinium dose (R2 = 0.41; p = 0.0046), compared to the average of peak maxima concentration. Correlation between area under the curve and dose suggests that LA-ICP-MS analysis of hair may be an effective method to evaluate gadolinium levels in subjects in vivo after exposure to GBCAs. This study demonstrates that analysis of human hair using techniques with high spatial resolution such as LA-ICP-MS has excellent potential to reveal time-dependent signatures of past exposures.

2D Graphene Oxide/Fe-MOF Nanozyme Nest with Superior Peroxidase-Like Activity and Its Application for Detection of Woodsmoke Exposure Biomarker.

Emerging nanomaterials such as nanozymes have recently been applied for the immunoassay-based detection of biomarkers. However, the inferior catalytic activity and low water solubility of nanozymes remain as the major limitations compared to natural enzymes. To overcome these limitations, we successfully synthesized a superior nanozyme with a structure of enriched 2D catalytic interface, namely Nanozyme Nest, which was composed of Fe-based metal-organic frameworks (Fe-MOF) and graphene oxide (GO). Then, we applied it in an ultrasensitive enzyme-linked immunosorbent assay (ELISA) for the detection of benzo[a]pyrene-7,8-diol 9,10-epoxide-DNA adduct (BPDE-DNA), which is a metabolite of benzo[a]pyrene (BP) and used as a typical biomarker of woodsmoke exposure in human blood. The Nanozyme Nest features amplified peroxidase-like catalytic ability from graphene and Fe-MOF due to their large surface area and abundant active sites. By using the proposed Nanozyme Nest-based ultrasensitive ELISA, the BPDE-DNA could be detected at a level as low as 0.268 ng/mL, and the obtained sensitivity was much higher than most of the widely used methods. Our work provides a novel strategy to design ultrasensitive immunosensors with advantages of amplified catalytic activity and improved water solubility compared to classic nanozymes. This illustrates the promising applications of the Nanozyme Nest-based immunosensors in point-of-care settings to conveniently detect exposures and diagnose diseases.

Mobile and Fixed-Site Measurements To Identify Spatial Distributions of Traffic-Related Pollution Sources in Los Angeles.

Mobile monitoring and fixed-site monitoring using passive sampling devices (PSD) are popular air pollutant measurement techniques with complementary strengths and weaknesses. This study investigates the utility of combining data from concurrent 2-week mobile monitoring and fixed-site PSD campaigns in Los Angeles in the summer and early spring to identify sources of traffic-related air pollutants (TRAP) and their spatial distributions. There were strong to moderate correlations between mobile and fixed-site PSD measurements of both NO2 and NO x in the summer and spring (Pearson's r between 0.43 and 0.79), suggesting that the two data sets can be reliably combined for source apportionment. PCA identified the major TRAP sources as light-duty vehicle emissions, diesel exhaust, crankcase vent emissions, and an independent source of combustion-derived ultrafine particle emissions. The component scores of those four sources at each site were significantly correlated across the two seasons (Pearson's r between 0.58 and 0.79). Spatial maps of absolute principal component scores showed all sources to be most prominent near major roadways and the central business district and the ultrafine particle source being, in addition, more prominent near the airport. Mobile monitoring combined with fixed-site PSD sampling can provide high spatial resolution estimates of TRAP and can reveal underlying sources of exposure variability.

An ultra low-cost smartphone device for in-situ monitoring of acute organophosphorus poisoning for agricultural workers.

In this work, we present an ultra-low-cost smartphone device for in situ quantification of OP poisoning severity. The performance of the lens-less smartphone spectrum apparatus (LeSSA) is evaluated using standard human Interleukin-6 (IL-6) immunoassay kits. Upon dose-response curve fitting, LeSSA demonstrates an accuracy of 99.5%. The limit of detection (LOD) of LeSSA was evaluated through comparison of 6.4 pg/ml with standard laboratory grade UV-vis spectrophotometer at 5.5 pg/ml. Evaluating the capacity of LeSSA in spike solution by combining plasma cholinesterase (PChE) and human plasma shows consistency at agreement of 97.6% between LeSSA and the laboratory instrument. For application demonstration, the activity of PChE for 24 agricultural workers' plasma samples was measured with LeSSA, showing exceptional agreement (r2 = 0.92) with the laboratory instrument reference. In addition to near laboratory grade accuracy, the total manufacturing cost of LeSSA is only $20 USD highlighting it's affordability. With LeSSA, clinicians can evaluate OP poisoning severity without the need to transport patient samples to facilities at far distances. Utilizing LeSSA, immediate results can be used for administration of appropriate treatment.

Ultrafine particle size as a tracer for aircraft turbine emissions.

Ultrafine particle number (UFPN) and size distributions, black carbon, and nitrogen dioxide concentrations were measured downwind of two of the busiest airports in the world, Los Angeles International Airport (LAX) and Hartsfield-Jackson International Airport (ATL - Atlanta, GA) using a mobile monitoring platform. Transects were located between 5 km and 10 km from the ATL and LAX airports. In addition, measurements were taken at 43 additional urban neighborhood locations in each city and on freeways. We found a 3-5 fold increase in UFPN concentrations in transects under the landing approach path to both airports relative to surrounding urban areas with similar ground traffic characteristics. The latter UFPN concentrations measured were distinct in size distributional properties from both freeways and across urban neighborhoods, clearly indicating different sources. Elevated concentrations of Black Carbon (BC) and NO2 were also observed on airport transects, and the corresponding pattern of elevated BC was consistent with the observed excess UFPN concentrations relative to other urban locations.

Correlations between short-term mobile monitoring and long-term passive sampler measurements of traffic-related air pollution.

Mobile monitoring has provided a means for broad spatial measurements of air pollutants that are otherwise impractical to measure with multiple fixed site sampling strategies. However, the larger the mobile monitoring route the less temporally dense measurements become, which may limit the usefulness of short-term mobile monitoring for applications that require long-term averages. To investigate the stationarity of short-term mobile monitoring measurements, we calculated long term medians derived from a mobile monitoring campaign that also employed 2-week integrated passive sampler detectors (PSD) for NOx, Ozone, and nine volatile organic compounds at 43 intersections distributed across the entire city of Baltimore, MD. This is one of the largest mobile monitoring campaigns in terms of spatial extent undertaken at this time. The mobile platform made repeat measurements every third day at each intersection for 6-10 minutes at a resolution of 10 s. In two-week periods in both summer and winter seasons, each site was visited 3-4 times, and a temporal adjustment was applied to each dataset. We present the correlations between eight species measured using mobile monitoring and the 2-week PSD data and observe correlations between mobile NOx measurements and PSD NOx measurements in both summer and winter (Pearson's r = 0.84 and 0.48, respectively). The summer season exhibited the strongest correlations between multiple pollutants, whereas the winter had comparatively few statistically significant correlations. In the summer CO was correlated with PSD pentanes (r = 0.81), and PSD NOx was correlated with mobile measurements of black carbon (r = 0.83), two ultrafine particle count measures (r =0.8), and intermodal (1-3 µm) particle counts (r = 0.73). Principal Component Analysis of the combined PSD and mobile monitoring data revealed multipollutant features consistent with light duty vehicle traffic, diesel exhaust and crankcase blow by. These features were more consistent with published source profiles traffic-related air pollutants than features based on the PSD data alone. Short-term mobile monitoring shows promise for capturing long-term spatial patterns of traffic-related air pollution, and is complementary to PSD sampling strategies.

Hair Manganese as an Exposure Biomarker among Welders.

Quantifying exposure and dose to manganese (Mn) containing airborne particles in welding fume presents many challenges. Common biological markers such as Mn in blood or Mn in urine have not proven to be practical biomarkers even in studies where positive associations were observed. However, hair Mn (MnH) as a biomarker has the advantage over blood and urine that it is less influenced by short-term variability of Mn exposure levels because of its slow growth rate. The objective of this study was to determine whether hair can be used as a biomarker for welders exposed to manganese. Hair samples (1cm) were collected from 47 welding school students and individual air Mn (MnA) exposures were measured for each subject. MnA levels for all days were estimated with a linear mixed model using welding type as a predictor. A 30-day time-weighted average MnA (MnA30d) exposure level was calculated for each hair sample. The association between MnH and MnA30d levels was then assessed. A linear relationship was observed between log-transformed MnA30d and log-transformed MnH. Doubling MnA30d exposure levels yields a 20% (95% confidence interval: 11-29%) increase in MnH. The association was similar for hair washed following two different wash procedures designed to remove external contamination. Hair shows promise as a biomarker for inhaled Mn exposure given the presence of a significant linear association between MnH and MnA30d levels.

Using exposure windows to explore an elusive biomarker: blood manganese.

PURPOSE: We sought to understand the time course between exposure to manganese (Mn) and uptake into the blood, to allow a more meaningful interpretation of exposure biomarker data, and to determine the utility of blood as a biomarker of Mn exposure. METHODS: Welder trainees were monitored over the course of a five-quarter training program. Each quarter, trainees gave eight blood samples and had personal air monitoring four times. A mixed model was fit to obtain estimates of airborne exposure by welding type (fixed effect), adjusted for subject (random effect). Considering weekends and days absent as zero exposure, estimated exposures were summed over various exposure windows and related to measured blood manganese (MnB) using a mixed model. RESULTS: A relationship consistent with zero was found between MnB and modeled 1 or 7 days of exposure. After 30 days of preceding exposure, a 1 mg-days/m(3) increase in air Mn is associated with a 0.57 ng/mL increase in MnB (95% CI -0.04, 1.19). Considering a 90-day exposure window and a cumulative exposure window, a 1 mg-days/m(3) increase in air Mn is associated with a 0.26 (95% CI 0.005, 0.51) and 0.09 (95% CI 0.006, 0.17) ng/mL increase in MnB, respectively. CONCLUSIONS: From this analysis, MnB may begin to act as a biomarker of Mn exposure over longer time periods, or at higher levels of exposure. This novel study design allowed investigation of how MnB relates to different time windows of exposure, representing the most robust Mn exposure assessment in the biomarker literature.

Nitro-PAH exposures of occupationally-exposed traffic workers and associated urinary 1-nitropyrene metabolite concentrations.

The assessment of occupational exposure to diesel exhaust (DE) is important from an epidemiological perspective. Urinary biomarkers of exposure have been proposed as a novel approach for measuring exposure to DE. In this study, we measured the concentrations of two urinary metabolites of 1-nitropyrene (1NP), a nitrated polycyclic aromatic hydrocarbon that has been suggested as a molecular marker of diesel particulate matter. These two metabolites, 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were determined in urine samples (10mL) from a small group of workers who were occupationally-exposed to vehicle exhaust in Trujillo, Peru, before and after their workshifts. Workshift exposures to 1NP, as well as PM2.5, 2-nitropyrene and 2-nitrofluoranthene, were also measured. Exposures to 1NP were similar in all studied workers, averaging 105±57.9pg/m3 (±standard deviation). Median urinary concentrations of the average of the pre- and post-exposure samples for 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were found to be 3.9 and 2.3pgmetabolite/mg creatinine, respectively in the group of occupationally-exposed subjects (n=17) studied. A direct relationship between workshift exposure to 1NP and urinary 1NP metabolites concentrations was not observed. However, the 1NP exposures and the creatinine-corrected urinary concentrations of the hydroxynitropyrene metabolites in these Peruvian traffic workers were similar to occupationally-exposed taxi drivers in Shenyang, China, and were higher than biomarker levels in office workers from Trujillo without occupational exposure to vehicle exhaust. This study provides further evidence that urinary metabolites of 1NP are associated with exposure to DE and may serve as a useful exposure biomarker.

Neighborhood-Scale Spatial Models of Diesel Exhaust Concentration Profile Using 1-Nitropyrene and Other Nitroarenes.

With emerging evidence that diesel exhaust exposure poses distinct risks to human health, the need for fine-scale models of diesel exhaust pollutants is growing. We modeled the spatial distribution of several nitrated polycyclic aromatic hydrocarbons (NPAHs) to identify fine-scale gradients in diesel exhaust pollution in two Seattle, WA neighborhoods. Our modeling approach fused land-use regression, meteorological dispersion modeling, and pollutant monitoring from both fixed and mobile platforms. We applied these modeling techniques to concentrations of 1-nitropyrene (1-NP), a highly specific diesel exhaust marker, at the neighborhood scale. We developed models of two additional nitroarenes present in secondary organic aerosol: 2-nitropyrene and 2-nitrofluoranthene. Summer predictors of 1-NP, including distance to railroad, truck emissions, and mobile black carbon measurements, showed a greater specificity to diesel sources than predictors of other NPAHs. Winter sampling results did not yield stable models, likely due to regional mixing of pollutants in turbulent weather conditions. The model of summer 1-NP had an R(2) of 0.87 and cross-validated R(2) of 0.73. The synthesis of high-density sampling and hybrid modeling was successful in predicting diesel exhaust pollution at a very fine scale and identifying clear gradients in NPAH concentrations within urban neighborhoods.

Blood α-synuclein in agricultural pesticide handlers in central Washington State.

Epidemiologic studies suggest that occupational exposure to pesticides might increase Parkinson disease risk. Some pesticides, such as the organophosphorus insecticide chlorpyrifos, appear to increase the expression of α-synuclein, a protein critically involved in Parkinson disease. Therefore, we assessed total blood cell α-synuclein in 90 specimens from 63 agricultural pesticide handlers, mainly Hispanic men from central Washington State, who participated in the state's cholinesterase monitoring program in 2007-2010. Additionally, in age-adjusted linear regression models for repeated measures, we assessed whether α-synuclein levels were associated with butyrylcholinesterase-chlorpyrifos adducts or cholinesterase inhibition measured in peripheral blood, or with self-reported pesticide exposure or paraoxonase (PON1) genotype. There was no evidence by any of those indicators that exposure to chlorpyrifos was associated with greater blood α-synuclein. We observed somewhat greater α-synuclein with the PON1-108T (lower paraoxonase enzyme) allele, and with ≥ 10 h of exposure to cholinesterase inhibiting insecticides in the preceding 30 days, but neither of these associations followed a clear dose-response pattern. These results suggest that selected genetic and environmental factors may affect α-synuclein blood levels. However, longitudinal studies with larger numbers of pesticide handlers will be required to confirm and elucidate the possible associations observed in this exploratory cross-sectional study.

Determinants of butyrylcholinesterase inhibition among agricultural pesticide handlers in Washington State: an update.

OBJECTIVES: Organophosphate (OP) and N-methyl-carbamate (CB) insecticides are used widely in agriculture to manage insect pests of economic importance. Agricultural workers are more likely to suffer exposure because of the widespread use of OP/CBs in agriculture, and pesticide-related illnesses among handlers may be more severe when compared to other farm workers. The goal of this study was to identify occupational and personal characteristics associated with butyrylcholinesterase (BuChE) inhibition in participants recruited from the Washington State Cholinesterase Monitoring Program from 2006 to 2011. METHODS: We conducted a longitudinal study among agricultural pesticide handlers in Washington State during the OP/CB spray season (March-July) over a 6-year period (2006-2011). Linear mixed effects regression models were used to evaluate BuChE inhibition in relation to self-reported occupational and personal characteristics. RESULTS: Relative to pre-season baseline levels, the mean decrease in BuChE activity during the OP/CB spray season over all years of the study period was 3.77% (P < 0.001). Greater BuChE inhibition was observed among handlers who reported using multiple OP/CBs (ß = -2.70, P = 0.045), mixed or loaded OP/CBs (ß = -3.97, P = 0.002), did not store personal protective equipment (PPE) in a locker at work (ß = -3.4, P = 0.014), or did not wear chemical-resistant boots (ß = -16.6, P < 0.001). DISCUSSION AND CONCLUSIONS: The Washington State Cholinesterase Monitoring Program has provided a valuable opportunity to evaluate potential sources of OP/CB exposure among agricultural pesticide handlers. Several previously reported associations were confirmed in the current analysis, which included a larger number of pesticide handlers enrolled over a longer time period. The use of multiple OP/CBs and mixing/loading activities were significant risk factors, and the use of chemical-resistant boots and lockers for PPE storage were protective factors. Our findings point toward logical interventions to reduce exposure such as the implementation of engineering controls for mixing/loading activities, requirements for appropriate footwear, and the regular use of lockers for PPE storage.

Multi-pollutant mobile platform measurements of air pollutants adjacent to a major roadway.

A mobile monitoring platform developed at the University of Washington Center for Clean Air Research (CCAR) measured 10 pollutant metrics (10 s measurements at an average speed of 22 km/hr) in two neighborhoods bordering a major interstate in Albuquerque, NM, USA from April 18-24 2012. 5 days of data sharing a common downwind orientation with respect to the roadway were analyzed. The aggregate results show a three-fold increase in black carbon (BC) concentrations within 10 meters of the edge of roadway, in addition to elevated nanoparticle concentration and particulate matter with aerodynamic diameter < 1 µm (PN1) concentrations. A 30% reduction in ozone concentration near the roadway was observed, anti-correlated with an increase in the oxides of nitrogen (NOx). In this study, the pollutants measured have been expanded to include polycyclic aromatic hydrocarbons (PAH), particle size distribution (0.25-32 µm), and ultra-violet absorbing particulate matter (UVPM). The raster sampling scheme combined with spatial and temporal measurement alignment provide a measure of variability in the near roadway concentrations, and allow us to use a principal component analysis to identify multi-pollutant features and analyze their roadway influences.

Blood manganese as an exposure biomarker: state of the evidence.

Despite evidence of adverse health effects resulting from exposure to manganese (Mn), biomarkers of exposure are poorly understood. To enhance understanding, mean blood Mn (MnB) and mean air Mn (MnA) were extracted from 63 exposure groups in 24 published papers, and the relationship was modeled using segmented regression. On a log/log scale, a positive association between MnA and MnB was observed among studies reporting MnA concentrations above about 10 µg/m(3), although interpretation is limited by largely cross-sectional data, study design variability, and differences in exposure monitoring methods. Based on the results of the segmented regression, we hypothesize that below the concentration of about 10 µg/m(3), Mn in the body is dominated by dietary Mn, and additional inhaled Mn only causes negligible changes in Mn levels unless the inhaled amount is substantial. However, stronger study designs are required to account for temporal characteristics of the MnA to MnB relationships that reflect the underlying physiology and toxicokinetics of Mn uptake and distribution. Thus, we present an inception cohort study design we have conducted among apprentice welders, and the analytical strengths this study design offers. To determine if blood could be a useful biomarker for Mn to be utilized by industrial hygienists in general industry requires additional time-specific analyses, which our inception cohort study design will allow.

Measurement of spatial and temporal variation in volatile hazardous air pollutants in Tacoma, Washington, using a mobile membrane introduction mass spectrometry (MIMS) system.

The objective of this study was to use membrane introduction mass spectrometry (MIMS), implemented on a mobile platform, in order to provide real-time, fine-scale, temporally and spatially resolved measurements of several hazardous air pollutants. This work is important because there is now substantial evidence that fine-scale spatial and temporal variations of air pollutant concentrations are important determinants of exposure to air pollution and adverse health outcomes. The study took place in Tacoma, WA during periods of impaired air quality in the winter and summer of 2008 and 2009. Levels of fine particles were higher in winter compared to summer, and were spatially uniform across the study area. Concentrations of vapor phase pollutants measured by membrane introduction mass spectrometry (MIMS), notably benzene and toluene, had relatively uniform spatial distributions at night, but exhibited substantial spatial variation during the day-daytime levels were up to 3-fold higher at traffic-impacted locations compared to a reference site. Although no direct side-by-side comparison was made between the MIMS system and traditional fixed site monitors, the MIMS system typically reported higher concentrations of specific VOCs, particularly benzene, ethylbenzene and naphthalene, compared to annual average concentrations obtained from SUMA canisters and gas chromatographic analysis at the fixed sites.

Evaluation of Orthotrichum lyellii moss as a biomonitor of diesel exhaust.

Exhaust from diesel combustion engines is an important contributor to urban air pollution and poses significant risk to human health. Diesel exhaust contains a chemical class known as nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and is enriched in 1-nitropyrene (1-NP), which has the potential to serve as a marker of diesel exhaust. The isomeric nitro-PAHs 2-nitropyrene (2-NP) and 2-nitrofluoranthene (2-NFL) are secondary pollutants arising from photochemical oxidation of pyrene and fluoranthene, respectively. Like other important air toxics, there is not extensive monitoring of nitro-PAHs, leading to gaps in knowledge about relative exposures and urban hotspots. Epiphytic moss absorbs water, nutrients, and pollutants from the atmosphere and may hold potential as an effective biomonitor for nitro-PAHs. In this study we investigate the suitability of Orthotrichum lyellii as a biomonitor of diesel exhaust by analyzing samples of the moss for 1-NP, 2-NP, and 2-NFL in the Seattle, WA metropolitan area. Samples were collected from rural parks, urban parks, residential, and commercial/industrial areas (N = 22 locations) and exhibited increasing concentrations across these land types. Sampling and laboratory method performance varied by nitro-PAH, but was generally good. We observed moderate to moderately strong correlation between 1-NP and select geographic variables, including summer normalized difference vegetation index (NDVI) within 250 m (r = -0.88, R2 = 0.77), percent impervious surface within 50 m (r = 0.83, R2 = 0.70), percent high development land use within 500 m (r = 0.77, R2 = 0.60), and distance to nearest secondary and connecting road (r = -0.75, R2 = 0.56). The relationships between 2-NP and 2-NFL and the geographic variables were generally weaker. Our results suggest O. lyellii is a promising biomonitor of diesel exhaust, specifically for 1-NP. To our knowledge this pilot study is the first to evaluate using moss concentrations of nitro-PAHs as biomonitors of diesel exhaust.

Olfactory tract/bulb metal concentration in Manganese-exposed mineworkers.

BACKGROUND: Manganese (Mn) is an essential micronutrient as well as a well-established neurotoxicant. Occupational and environmental exposures may bypass homeostatic regulation and lead to increased systemic Mn levels. Translocation of ultrafine ambient airborne particles via nasal neuronal pathway to olfactory bulb and tract may be an important pathway by which Mn enters the central nervous system. OBJECTIVE: To measure olfactory tract/bulb tissue metal concentrations in Mn-exposed and non-exposed mineworkers. METHODS: Using inductively coupled plasma-mass spectrometry (ICP-MS), we measured and compared tissue metal concentrations in unilateral olfactory tracts/bulbs of 24 Mn-exposed and 17 non-exposed South African mineworkers. We used linear regression to investigate the association between cumulative Mn exposures and olfactory tract/bulb Mn concentration. RESULTS: The difference in mean olfactory tract/bulb Mn concentrations between Mn-exposed and non-Mn exposed mineworkers was 0.16 µg/g (95% CI -0.11, 0.42); but decreased to 0.09 µg/g (95% CI 0.004, 0.18) after exclusion of one influential observation. Olfactory tract/bulb metal concentration and cumulative Mn exposure suggested there may be a positive association; for each mg Mn/m3-year there was a 0.05 µg/g (95% CI 0.01, 0.08) greater olfactory tract/bulb Mn concentration overall, but -0.003 (95% CI -0.02, 0.02) when excluding the three influential observations. Recency of Mn exposure was not associated with olfactory tract/bulb Mn concentration. CONCLUSIONS: Our findings suggest that Mn-exposed mineworkers might have higher olfactory tract/bulb tissue Mn concentrations than non-Mn exposed mineworkers, and that concentrations might depend more on cumulative dose than recency of exposure.

Urinary polycyclic aromatic hydrocarbon (PAH) metabolite concentrations in three pregnancy cohorts from 7 U.S. study sites.

OBJECTIVE: Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with adverse birth and developmental outcomes in children. We aimed to describe prenatal PAH exposures in a large, multisite U.S. consortium. METHODS: We measured 12 mono-hydroxylated metabolites (OH-PAHs) of 7 PAHs (naphthalene, fluorene, phenanthrene, pyrene, benzo(c)phenanthrene, chrysene, benz(a)anthracene) in mid-pregnancy urine of 1,892 pregnant individuals from the ECHO PATHWAYS consortium cohorts: CANDLE (n = 988; Memphis), TIDES (n = 664; Minneapolis, Rochester, San Francisco, Seattle) and GAPPS (n = 240; Seattle and Yakima, WA). We described concentrations of 8 OH-PAHs of non-smoking participants (n = 1,695) by site, socioeconomic characteristics, and pregnancy stage (we report intraclass correlation coefficients (ICC) for n = 677 TIDES participants). RESULTS: Exposure to the selected PAHs was ubiquitous at all sites. 2-hydroxynaphthalene had the highest average concentrations at all sites. CANDLE had the highest average concentrations of most metabolites. Among non-smoking participants, we observed some patterns by income, education, and race but these were not consistent and varied by site and metabolite. ICCs of repeated OH-PAH measures from TIDES participants were ≤ 0.51. CONCLUSION: In this geographically-diverse descriptive analysis of U.S. pregnancies, we observed ubiquitous exposure to low molecular weight PAHs, highlighting the importance of better understanding PAH sources and their pediatric health outcomes attributed to early life PAH exposure.