Assessment of Dermal and Inhalation Exposure to Permethrin During Field Treatment of Military Uniforms.

INTRODUCTION: Permethrin is a common pesticide spray-applied to civilian clothing and military uniforms for protection against biting arthropods in an effort to reduce risks to arthropod-borne diseases. During mass clothing spray events, exposure is possible through the dermal, inhalation, and ingestion routes. The potentially exposed population during a spray event includes the pesticide applicator(s) and working party (personnel who handle clothing/uniforms by positioning on the ground, flipping, and removing after spraying is complete). Previous investigation is limited regarding permethrin exposure via multiple routes of entry. Additionally, most exposure assessments are limited to pesticide applicators rather than working party that support applicator personnel. The purpose of this investigation was to conduct a multi-route exposure assessment for all personnel normally participating in mass permethrin military uniform treatments. MATERIALS AND METHODS: The protocol and Informed Consent Document were approved by the Uniformed Services University of the Health Sciences (USUHS) Institutional Review Board (IRB) before fieldwork initiation (IRB number: USUHS.2019-032). Sampling occurred during routine spray events performed by 14 U.S. Navy personnel (3 applicators and 11 working party) over 2 days. Personal exposures were measured with dermal sampling, and airborne concentrations were measured with area air sampling. Permethrin area air sampling and analysis were conducted using OSHA Versatile Sampler-2 sampling media (n = 36). Dermal exposure was measured using dosimeter gloves (n = 26) and a dermal patch (n = 26) worn by study participants. RESULTS: All air samples were reported below the 0.4 µg limit of quantification. Glove sample results ranged from 45 to 120,000 µg and patch results ranged from 0.57 to 45 µg. A repeated-measures ANOVA showed non-statistically significant differences in dermal concentrations (P-value = .8340) between the applicators and working party in patches and gloves. CONCLUSIONS: Results suggest dermal contact is the primary route of exposure compared to inhalation when mass spraying clothing with permethrin. Similar dermal exposures between these two occupations may necessitate reconsidering risk assessment procedures, training and personal protective equipment (PPE) requirements for mass spray uniform treatments. Specifically, while PPE requirements for applicators are highly regulated by the Armed Forces Pest Management Board and include items such as Tyvek suits, chemical protective gloves, and air-purifying respirators, PPE was not regulated for working party personnel before this investigation.

Noise characterization of "effective quiet" areas on a U.S. Navy aircraft carrier.

The purpose of this investigation was to characterize noise levels in spaces designated as "effective quiet" areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for "effective quiet" areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24 hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels "A" weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8-105.4 dBA; (2) Leq (flt ops): 70-101.2 dBA; and (3) Leq (non-flt ops): 39.4-104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the "effective quiet" 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in "effective quiet" areas (p = 0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p = 0.001). Results suggest noise levels in "effective quiet" areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.

Living at Work: 24-hour Noise Exposure Aboard US Navy Aircraft Carriers.

BACKGROUND: Personnel assigned to aircraft carriers are exposed to a variety of noise sources from equipment and flight deck operations for durations >12 h. Personnel work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping and relaxation areas are in proximity to one another which provides little recovery time from hazardous noise. This investigation describes noise levels measured over a 24-h period on a US Navy aircraft carrier during flight operations for different populations of aircraft carrier personnel. METHODS: Personal noise monitoring occurred from 23 to 28 January 2014 aboard a US Navy Nimitz-class aircraft carrier during a routine at-sea period. Fifty-nine study volunteers were assigned to similar exposure groups (SEGs). The SEGs were compared to determine which groups were at greatest risk of hazardous noise exposure. Statistical analysis was conducted with SPSS version 24 using an alpha level of 0.05. RESULTS: Mean 24-h equivalent continuous sound levels Leq(24-h) and on-duty time weighted averages (TWA(on-duty)) ranged from 71 to 127 decibels A weighted (dBA). The 80 dBA American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for 24-h noise exposure was exceeded by 93% of the study volunteers. The 85 dBA ACGIH TLV and Department of Defense Occupational exposure limit for 8-h noise exposures was exceeded by 68% of the population. Leq(off-duty) ranged from 38 to 102 dBA with 61% of the population exceeding the 70 dBA ACGIH TLV classified as effective quiet to allow for temporary threshold shift recovery. SEG 2 Flight Deck Launch and Recovery had significantly higher 24-h noise exposures than SEG 3 Damage Control Maintenance and Repair (P = 0.01), SEG 5 Supply (P = 0.01), and SEG 7 Administrative/Professional (P = 0.009). Similar results were found for TWA(on-duty) noise exposures. Median TWA(on-duty) and Leq(24-h) for SEG 2 were 16-21 dB higher than SEG 3, 5, and 7. There were no significant differences between off-duty Leq noise exposures according to SEG. DISCUSSION/CONCLUSIONS: SEGs located on the flight deck (SEGs 1 and 2) and SEGs responsible for maintenance and repair activities (SEGs 3 and 4) supporting flight operations had the highest TWA(on-duty) and Leq(24-h). These findings raise serious concerns because high noise exposures both on- and off-duty may result in immediate acoustic trauma and development of temporary threshold shifts, which, if unresolved with auditory rest, may lead to permanent hearing loss.

Association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid in U.S. Army Mask Confidence Training.

This study was conducted among U.S. Army soldiers to evaluate the association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid (CHA) detected in test subjects (n = 87) after completion of Mask Confidence Training. CS exposures ranged 0.086-4.9 mg/m³ ([Formula: see text] = 2.7 mg/m³). CHA levels (corrected for creatinine) at 2-, 8-, 24-, and 30-hr post-exposure resulted in ranges of 94.6-1120 µg/g-cr ([Formula: see text] = 389 µg/g-cr), 15.80-1170 µg/g-cr ([Formula: see text] = 341 µg/g-cr), 4.00-53.1 µg/g-cr ([Formula: see text] = 19.3 µg/g-cr), and 1.99-28.4 µg/g-cr ([Formula: see text] = 10.6 µg/g-cr), respectively. Spearman's correlation revealed CHA levels strongly correlated with time sampled (r = -0.748, p < 0.05) and weakly correlated with CS concentration (r = 0.270, p < 0.05). A linear relationship was observed between CHA, CS concentration, and time of urine sample according to the following regression equation: ln(CHA, µg/g-cr) = 5.423 + 0.316 (CS conc., mg/m³) - 0.002 (time sampled), (R = 0.910, R² = 0.827, p < 0.05). This relationship suggests that CHA has the potential to be an effective retrospective indicator of CS exposure in future biomarker developments.

O-chlorobenzylidene malononitrile (CS riot control agent) exposure in a U.S. Army basic combat training cohort.

All U.S. Army soldiers participate in mask confidence training during initial military training and periodically throughout their careers. Training is conducted by dispersing the riot control agent, o-chlorobenzylidene malononitrile (CS), in a relatively air-tight structure where soldiers enter and conduct a series of exercises that culminate with mask removal. The study described here quantified CS concentrations experienced by 6,723 trainees and seven chamber operators during U.S. Army basic combat training at Fort Jackson, South Carolina, from August 1 to September 25, 2012. All 6,723 trainees were potentially exposed to CS concentrations exceeding the American Conference of Governmental Industrial Hygienists threshold limit value-ceiling (TLV-C) (0.39 mg/m3), 6,589 of which were potentially exposed to concentrations exceeding the value deemed immediately dangerous to life and health (IDLH) (2.0 mg/m3) by the National Institute for Occupational Safety and Health. All chamber operators were exposed to concentrations exceeding both the TLV-C and the IDLH.

Impact of temperature and storage duration on the chemical and odor quality of military packaged water in polyethylene terephthalate bottles.

The impact of temperature and storage time on military packaged water (MPW) quality was examined at four temperatures (23.0 °C to 60.0 °C) for 120 days. Polyethylene terephthalate (PET) bottles were filled in California and Afghanistan with unbuffered water treated by reverse osmosis. The US military's water pH long-term potability standard was exceeded, and US Food and Drug Administration (USFDA) and US Environmental Protection Agency (USEPA) drinking water pH and odor intensity limits were also exceeded. During a 70 day exposure period, Port Hueneme MPW total organic carbon and total trihalomethane levels increased from < 0.25mg/L to 2.0 ± 0.0mg/L and <0.05 µg/L to 51.5 ± 2.1 µg/L, respectively. PET released organic contaminants into MPW and residual disinfectant generated trihalomethane contaminants. After 14 days at 37.7 °C and 60.0 °C, Afghanistan MPW threshold odor number values were 8.0 and 8.6, respectively. Total organic carbon concentration only increased with exposure duration at 60.0 °C. Acetaldehyde and formaldehyde contaminants were not detected likely due to the high method detection limits applied in this study. Phthalate contaminants detected and their maximum levels were butylbenzylphthalate (BBP) 0.43 µg/L, di-n-butylphthalate (DnBP) 0.38 µg/L, di(2-ethylhexyl)phthalate (DEHP) 0.6 µg/L, and diethylphthalate (DEP) 0.32 µg/L. Antimony was only detected in 60.0 °C Afghanistan MPW on Day 28 and beyond, and its maximum concentration was 3.6 ± 0.3 µg/L. No antimony was found in bottles exposed to lesser temperatures. Environmental health, PET synthesis and bottle manufacturers, and bottle users can integrate results of this work to improve health protective decisions and doctrine.