Last data update: Nov 11, 2024. (Total: 48109 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Alexander-Scott M[original query] |
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Exposure assessment of polycyclic aromatic hydrocarbons in refined coal tar sealant applications
McCormick S , Snawder JE , Chen IC , Slone J , Calafat AM , Wang Y , Meng L , Alexander-Scott M , Breitenstein M , Johnson B , Meadows J , Fairfield Estill C . Int J Hyg Environ Health 2022 242 113971 BACKGROUND: Refined coal tar sealant (RCTS) emulsions are used to seal the surface of asphalt pavement. Nine of the 22 polycyclic aromatic hydrocarbons (PAHs) evaluated in this study are classified as known, probable, or possible human carcinogens. Exposure assessment research for RCTS workers has not been published previously. OBJECTIVES: The overall objective of this study was to develop a representative occupational exposure assessment of PAH exposure for RCTS workers based on worksite surveys. The specific aims were to: 1) quantify full-shift airborne occupational exposures to PAHs among RCTS workers; 2) quantify workers' dermal exposures to PAHs; 3) quantify biomarkers of PAH exposure in workers' urine; 4) identify specific job titles associated with RCTS exposure; and 5) apply these results to a biological exposure index to assess risk of potential genotoxicity from occupational exposures. METHODS: A total of twenty-one RCTS workers were recruited from three companies. Personal and area air samples were collected using a modification of NIOSH Method 5515. Dermal exposure was assessed by hand and neck wipes before and after shifts. Twenty-two PAHs were quantified via gas chromatography-mass spectrometry selected ion monitoring. Internal dose was estimated by quantifying select PAH metabolites in pre- and post-shift urine samples using on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. RESULTS: PAH levels in the worker breathing zones were highest for naphthalene, acenaphthene, and phenanthrene, with geometric means of 52.1, 11.4, and 9.8 μg/m(3), respectively. Hand wipe levels of phenanthrene, fluoranthene and pyrene were the highest among the 22 PAHs with geometric means of 7.9, 7.7, and 5.5 μg/cm(2), respectively. Urinary PAH biomarkers for naphthalene, fluorene, phenanthrene, and pyrene were detected in all workers and were higher for post-shift samples than those collected pre-shift. Urinary concentrations of the metabolite 1-hydroxypyrene were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for this metabolite in 89 percent of post-shift samples collected on the final day of the work week or field survey. Statistically significances were found between concentrations of fluorene, naphthalene, and phenanthrene in the breathing zone of workers and their corresponding urinary PAH biomarkers. Workers were placed in two work place exposure groups: applicators and non-applicators. Applicators had higher total PAH concentrations in personal breathing zone (PBZ) air samples than non-applicators and were more likely to have post-shift hand wipe concentrations significantly higher than pre-shift concentrations. Concentrations of post-shift urinary biomarkers were higher, albeit not significantly, for applicators than non-applicators. CONCLUSIONS: The exposure results from RCTS worker samples cannot be explained by proximal factors such as nearby restaurants or construction. Air and skin concentration levels were substantially higher for RCTS workers than previously published levels among asphalt workers for all PAHs. PAH profiles on skin wipes were more consistent with RCTS sealant product than air samples. Last day post-shift urinary concentrations of 1-hydroxypyrene greatly exceeded the ACGIH BEI benchmark of 2.5 μg/L in 25 of 26 samples, which suggests occupational exposure and risk of genotoxicity. When pyrene and benzo[a]pyrene were both detected, concentration ratios from personal exposure samples were used to calculate the adjusted BEI. Concentrations of 1-hydroxypyrene exceeded the adjusted BEIs for air, hand wipes, and neck wipes in most cases. These results indicate the need to increase safety controls and exposure mitigation for RCTS workers. |
The Wildland Firefighter Exposure and Health Effect (WFFEHE) Study: Rationale, design, and methods of a repeated-measures study
Navarro KM , Butler CR , Fent K , Toennis C , Sammons D , Ramirez-Cardenas A , Clark KA , Byrne DC , Graydon PS , Hale CR , Wilkinson AF , Smith DL , Alexander-Scott MC , Pinkerton LE , Eisenberg J , Domitrovich JW . Ann Work Expo Health 2021 66 (6) 714-727 The wildland firefighter exposure and health effect (WFFEHE) study was a 2-year repeated-measures study to investigate occupational exposures and acute and subacute health effects among wildland firefighters. This manuscript describes the study rationale, design, methods, limitations, challenges, and lessons learned. The WFFEHE cohort included fire personnel ages 18-57 from six federal wildland firefighting crews in Colorado and Idaho during the 2018 and 2019 fire seasons. All wildland firefighters employed by the recruited crews were invited to participate in the study at preseason and postseason study intervals. In 2019, one of the crews also participated in a 3-day midseason study interval where workplace exposures and pre/postshift measurements were collected while at a wildland fire incident. Study components assessed cardiovascular health, pulmonary function and inflammation, kidney function, workplace exposures, and noise-induced hearing loss. Measurements included self-reported risk factors and symptoms collected through questionnaires; serum and urine biomarkers of exposure, effect, and inflammation; pulmonary function; platelet function and arterial stiffness; and audiometric testing. Throughout the study, 154 wildland firefighters participated in at least one study interval, while 144 participated in two or more study interval. This study was completed by the Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health through a collaborative effort with the U.S. Department of Agriculture Forest Service, Department of the Interior National Park Service, and Skidmore College. Conducting research in the wildfire environment came with many challenges including collecting study data with study participants with changing work schedules and conducting study protocols safely and operating laboratory equipment in remote field locations. Forthcoming WFFEHE study results will contribute to the scientific evidence regarding occupational risk factors and exposures that can impact wildland firefighter health over a season and across two wildland fire seasons. This research is anticipated to lead to the development of preventive measures and policies aimed at reducing risk for wildland firefighters and aid in identifying future research needs for the wildland fire community. |
Occupational safety and health and illicit opioids: State of the research on protecting against the threat of occupational exposure
Alexander-Scott M , Greenawald L , Chiu S , Broadwater K , Hirst D , Snawder J , Roberts J , Weber A , Knuth M . New Solut 2021 31 (3) 315-329 The nationwide opioid crisis continues to affect not only people who use opioids but also communities at large by increasing the risk of accidental occupational exposure to illicit opioids. In addition, the emergence of highly potent synthetic opioids such as fentanyl and carfentanil increases the need to protect workers who may encounter unknown drug substances during job activities. To support the National Institute for Occupational Safety and Health Opioids Research Gaps Working Group, we examined the state of the literature concerning methods to protect workers against accidental occupational exposure to illicit opioids, and have identified unmet research needs concerning personal protective equipment, decontamination methods, and engineering controls. Additional studies are needed to overcome gaps in technical knowledge about personal protective equipment, decontamination, and control methods, and gaps in understanding how these measures are utilized by workers. Increasing our knowledge of how to protect against exposure to illicit opioids has the potential to improve occupational health across communities. |
An optimized method for sample collection, extraction, and analysis of fentanyl and fentanyl analogs from a non-porous surface
Ciesielski AL , Wagner JR , Alexander-Scott M , Snawder J . Talanta 2021 228 122210 Illicit use of the potent opioid fentanyl and its analogs (fentanyls) are on the rise in the United States. As use increases, drug production tends to also increase, leading to more locations being contaminated with the potentially lethal substance. Because fentanyl-contaminated locations may present a risk to the general public, a method for sampling, identifying, and quantitating these fentanyls from surfaces is in need. This research developed and optimized a surface-wipe collection and extraction method for 17 fentanyls and 10 common fentanyl adulterants from a non-porous surface and quantitated the amount of each compound collected with liquid chromatography tandem mass spectrometry. The final, optimized surface-wipe method resulted in an average collection and extraction efficiency (±SD) of 62.0 (±14.0)%, with a range of 34.1 (±2.6) – 82.5 (±9.6)%. While legislation has yet to be implemented regarding remediation levels for fentanyl-contaminated locations, when such legislation is drafted, this method can be implemented to determine the safety of these locations prior to and after decontamination has occurred. |
Surface contamination generated by "one-pot" methamphetamine production
Ciesielski AL , Wagner JR , Alexander-Scott M , Smith J , Snawder J . J Chem Health Saf 2021 28 (1) 49-54 Methamphetamine production is the most common form of illicit drug manufacture in the United States. The "one-pot"method is the most prevalent methamphetamine synthesis method and is a modified Birch reduction, reducing pseudoephedrine with lithium and ammonia gas generated in situ. This research examined the amount of methamphetamine surface contamination generated by one-pot syntheses or "cooks", as well as the effectiveness of hosing with water as a simplified decontamination technique, to assess associated public health and environmental consequences. Concentrations of methamphetamine contamination were examined prior to production, after production, and after decontamination with water. Contamination was qualitatively field screened using lateral flow immunoassays and quantitatively assessed using a fluorescence covalent microbead immunosorbent assay. Following screening, 0 of 23 pre-cook samples, 29 of 41 post-cook samples, and 5 of 27 post-decontamination samples were positive. Quantitatively, one pre-cook sample had a methamphetamine concentration of 1.36 ng/100 cm2. Post-cook and post-decontamination samples had average methamphetamine concentrations of 26.50 ± 63.83 and 6.22 ± 12.17 ng/100 cm2, respectively. While all one-pot methamphetamine laboratories generate different amounts of waste, depending on the amount of precursors used and whether the reaction vessel remained uncompromised, this study examined the surface contamination generated by a popular one-pot method known to law enforcement. By understanding the amount of surface contamination generated by common methods of one-pot methamphetamine production and the effectiveness of decontamination techniques used to remediate them, health risks associated with these production sites can be better understood and environmental contamination can be mitigated. |
Meningococcal carriage among a university student population - United States, 2015.
Breakwell L , Whaley M , Khan UI , Bandy U , Alexander-Scott N , Dupont L , Vanner C , Chang HY , Vuong JT , Martin S , MacNeil JR , Wang X , Meyer SA . Vaccine 2017 36 (1) 29-35 OBJECTIVES: Several outbreaks of serogroup B meningococcal disease have occurred among university students in recent years. In the setting of high coverage of the quadrivalent meningococcal conjugate vaccine and prior to widespread use of serogroup B meningococcal vaccines among adolescents, we conducted surveys to characterize the prevalence and molecular characteristics of meningococcal carriage among university students. METHODS: Two cross-sectional oropharyngeal carriage surveys were conducted among undergraduates at a Rhode Island university. Isolates were characterized using slide agglutination, real-time polymerase chain reaction (rt-PCR), and whole genome sequencing. Adjusted prevalence ratios and 95% confidence intervals were calculated using Poisson regression to determine risk factors for carriage. RESULTS: A total of 1837 oropharyngeal specimens were obtained from 1478 unique participants. Overall carriage prevalence was 12.7-14.6% during the two survey rounds, with 1.8-2.6% for capsular genotype B, 0.9-1.0% for capsular genotypes C, W, or Y, and 9.9-10.8% for nongroupable strains by rt-PCR. Meningococcal carriage was associated with being male, smoking, party or club attendance, recent antibiotic use (inverse correlation), and recent respiratory infections. CONCLUSIONS: In this university setting, the majority of meningococcal carriage was due to nongroupable strains, followed by serogroup B. Further evaluation is needed to understand the dynamics of serogroup B carriage and disease among university students. |
Measurement of area and personal breathing zone concentrations of diesel particulate matter (DPM) during oil and gas extraction operations, including hydraulic fracturing
Esswein EJ , Alexander-Scott M , Snawder J , Breitenstein M . J Occup Environ Hyg 2017 15 (1) 0 Diesel engines serve many purposes in modern oil and gas extraction activities. Diesel particulate matter (DPM) emitted from diesel engines is a complex aerosol that may cause adverse health effects depending on exposure dose and duration. This study reports on personal breathing zone (PBZ) and area measurements for DPM (expressed as elemental carbon) during oil and gas extraction operations including drilling, completions (which includes hydraulic fracturing) and servicing work. Researchers at the National Institute for Occupational Safety and Health (NIOSH) collected 104 full-shift air samples (49 PBZ and 55 area) in Colorado, North Dakota, Texas, and New Mexico during a four year period from 2008-2012 The arithmetic mean (AM) of the full shift TWA PBZ samples was 10 microg/m3; measurements ranged from 0.1 to 52 microg/m3. The geometric mean (GM) for the PBZ samples was 7 microg/m3. The AM of the TWA area measurements was 17 microg/m3 and ranged from 0.1 to 68 microg/m3. The GM for the area measurements was 9.5 microg/m3. Differences between the GMs of the PBZ samples and area samples were not statistically different (P>0.05). Neither the Occupational Safety and Health Administration (OSHA), NIOSH, nor the American Conference of Governmental Industrial Hygienists (ACGIH) have established occupational exposure limits (OEL) for DPM. However, the State of California, Department of Health Services lists a time-weighted average (TWA) OEL for DPM as elemental carbon (EC) exposure of 20 microg/m3. Five of 49 (10.2%) PBZ TWA measurements exceeded the 20 microg/m3 EC criterion. These measurements were collected on Sandmover and Transfer Belt (T-belt) Operators, Blender and Chemical Truck Operators, and Water Transfer Operators during hydraulic fracturing operations. Recommendations to minimize DPM exposures include elimination (locating diesel-driven pumps away from well sites), substitution, (use of alternative fuels), engineering controls using advanced emissions controls technologies, administrative controls (configuration of well sites), hazard communication and worker training. |
Meningococcal carriage evaluation in response to a serogroup B meningococcal disease outbreak and mass vaccination campaign at a college - Rhode Island, 2015-2016
Soeters HM , Whaley M , Alexander-Scott N , Kanadanian KV , MacNeil JR , Martin SW , McNamara LA , Sicard K , Vanner C , Vuong J , Wang X , Bandy U , Patel M . Clin Infect Dis 2017 64 (8) 1115-1122 BACKGROUND: Serogroup B meningococcal disease caused 7 US university outbreaks during 2013-2016. Neisseria meningitidis can be transmitted via asymptomatic nasopharyngeal carriage. MenB-FHbp (factor H binding protein), a serogroup B meningococcal (MenB) vaccine, was used to control a college outbreak. We investigated MenB-FHbp impact on meningococcal carriage. METHODS: Four cross-sectional surveys were conducted in conjunction with MenB-FHbp vaccination campaigns. Questionnaires and oropharyngeal swabs were collected from students. Specimens were evaluated using culture, slide agglutination, real-time polymerase chain reaction (rt-PCR), and whole genome sequencing. Adjusted prevalence ratios (aPRs) were calculated using generalized estimating equations. RESULTS: During each survey, 20%-24% of participants carried any meningococcal bacteria and 4% carried serogroup B by rt-PCR. The outbreak strain (ST-9069) was not detected during the initial survey; 1 student carried ST-9069 in the second and third surveys. No carriage reduction was observed over time or with more MenB-FHbp doses. In total, 615 students participated in multiple surveys: 71% remained noncarriers, 8% cleared carriage, 15% remained carriers, and 7% acquired carriage. Ten students acquired serogroup B carriage: 3 after 1 MenB-FHbp dose, 4 after 2 doses, and 3 after 3 doses. Smoking (aPR, 1.3; 95% confidence interval [CI], 1.1-1.5) and male sex (aPR, 1.3; 95% CI, 1.1-1.5) were associated with increased meningococcal carriage. CONCLUSIONS: Carriage prevalence on campus remained stable, suggesting MenB-FHbp does not rapidly reduce meningococcal carriage or prevent serogroup B carriage acquisition. This reinforces the need for high vaccination coverage to protect vaccinated individuals and chemoprophylaxis for close contacts during outbreaks. |
Potential impact of co-infections and co-morbidities prevalent in Africa on influenza severity and frequency: a systematic review
Cohen AL , McMorrow M , Walaza S , Cohen C , Tempia S , Alexander-Scott M , Widdowson MA . PLoS One 2015 10 (6) e0128580 Infectious diseases and underlying medical conditions common to Africa may affect influenza frequency and severity. We conducted a systematic review of published studies on influenza and the following co-infections or co-morbidities that are prevalent in Africa: dengue, malaria, measles, meningococcus, Pneumocystis jirovecii pneumonia (PCP), hemoglobinopathies, and malnutrition. Articles were identified except for influenza and PCP. Very few studies were from Africa. Sickle cell disease, dengue, and measles co-infection were found to increase the severity of influenza disease, though this is based on few studies of dengue and measles and the measles study was of low quality. The frequency of influenza was increased among patients with sickle cell disease. Influenza infection increased the frequency of meningococcal disease. Studies on malaria and malnutrition found mixed results. Age-adjusted morbidity and mortality from influenza may be more common in Africa because infections and diseases common in the region lead to more severe outcomes and increase the influenza burden. However, gaps exist in our knowledge about these interactions. |
Serogroup B meningococcal disease outbreak and carriage evaluation at a college - Rhode Island, 2015
Soeters HM , McNamara LA , Whaley M , Wang X , Alexander-Scott N , Kanadanian KV , Kelleher CM , MacNeil J , Martin SW , Raines N , Sears S , Vanner C , Vuong J , Bandy U , Sicard K , Patel M . MMWR Morb Mortal Wkly Rep 2015 64 (22) 606-7 On February 2, 2015, the Rhode Island Department of Health was notified of a case of meningococcal disease in a male undergraduate student at Providence College. Three days later, a second case was reported in a male undergraduate with no contact with the first student, indicating an attack rate of 44 cases per 100,000 students, nearly 500 times higher than the national incidence of 0.15 cases per 100,000 among persons aged 17-22 years (Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, unpublished data, 2013). Both cases were caused by a rare outbreak strain of Neisseria meningitidis serogroup B (ST-9069); neither case was fatal. In response to the outbreak, potential contacts received antibiotic chemoprophylaxis, and a mass vaccination campaign with a recently licensed serogroup B meningococcal (MenB) vaccine was implemented. In collaboration with CDC, the first phase of a meningococcal carriage evaluation was undertaken. |
Evaluation of some potential chemical exposure risks during flowback operations in unconventional oil and gas extraction: preliminary results
Esswein EJ , Snawder J , King B , Breitenstein M , Alexander-Scott M , Kiefer M . J Occup Environ Hyg 2014 11 (10) D174-84 Approximately 562,000 workers were employed in the U.S. oil and gas extraction industry in 2012; nearly half of those workers were employed by well servicing companies, which include companies that conduct hydraulic fracturing and flowback operations. To understand possible risks for chemical exposures in modern oil and gas extraction operations, the National Institute for Occupational Safety and Health (NIOSH) initiated the Field Effort to Assess Chemical Exposures in Oil and Gas Workers. Initial research identified exposure risks for respirable crystalline silica during hydraulic fracturing as an occupational health hazard. This report describes industrial hygiene sampling during flowback operations at six unconventional oil and gas extraction sites in Colorado and Wyoming during spring and summer 2013. The results are considered preliminary; additional exposure assessments are needed to better understand the range of possible exposures, risk factors, and controls during flowback operations. | |
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