Acoustic monitoring and analyses of air gun, pile driving, vessel, and ambient sounds during the 2015 seismic surveys on the Sakhalin shelf.

During the summer of 2015, four 4D seismic surveys were conducted on the northeastern Sakhalin shelf near the feeding grounds of the Korean-Okhotsk (western) gray whale (Eschrichtius robustus) population. In addition to the seismic surveys, onshore pile driving activities and vessel operations occurred. Forty autonomous underwater acoustic recorders provided data in the 2 Hz to15 kHz frequency band. Recordings were analyzed to evaluate the characteristics of impulses propagating from the seismic sources. Acoustic metrics analyzed comprised peak sound pressure level (PK), mean square sound pressure level (SPL), sound exposure level (SEL), T100%, T90% (the time intervals that contain the full and 90% of the energy of the impulse), and kurtosis. The impulses analyzed differed significantly due to the variability and complexity of propagation in the shallow water of the northeast Sakhalin shelf. At larger ranges, a seismic precursor propagated in the seabed ahead of the acoustic impulse, and the impulses often interfered with each other, complicating analyses. Additional processing of recordings allowed evaluation and documentation of relevant metrics for pile driving, vessel sounds, and ambient background levels. The computed metrics were used to calibrate acoustic models, generating time resolved estimates of the acoustic levels from seismic surveys, pile driving, and vessel operations on a gray whale distribution grid and along observed gray whale tracks. This paper describes the development of the metrics and the calibrated acoustic models, both of which will be used in work quantifying gray whale behavioral and distribution responses to underwater sounds and to determine whether these observed responses have the potential to impact important parameters at the population level (e.g., reproductive success).

[Forensic examination of air gun dart wounds]. / Sudebno-meditsinskaya otsenka ranenii drotikami, metaemymi iz dukhovykh ruzhei.

The objective was to study the mechanism of formation of experimental wounds of the human body dummy by 12 different types of common air gun darts. The impact of dart tips design features on macro- and microscopic morphological patterns of wounds was established; the description of further laboratory diagnostics of the wounds was provided.

Air Guns: A Contemporary Review of Injuries at Six Pediatric Level I Trauma Centers.

BACKGROUND: Studies spanning the last three decades demonstrated the injury causing capability of air gun (AG) projectiles. Recent studies have suggested the impact and incidence of these injuries may be declining because of edcational efforts. We hypothesize that injuries in the pediatric population resulting from AGs remain a significant health concern. METHODS: A retrospective review (1/1/2007 to 12/31/2016), of AG-injured children < 19 years old, was performed across six level I Pediatric Trauma Centers, part of the ATOMAC research consortium. AG injuries were defined as injuries sustained by ball-bearing or pellet air-powered guns. Paint ball and soft foam AGs were excluded. Following institutional review board approval, patients were identified by ICD code from the trauma registry. Included were demographic data, injury severity scores, length of stay (LOS), outcome at discharge, and overall cost of admission. Descriptive statistics and parametric tests were employed. RESULTS: A total of 499 patients sustained injuries. Mean age 9.5 (±4.0) y; 81% of victims were male; all survived to hospital discharge. 30% (n = 151) required operative intervention. Hospital LOS was 2.3 (±2.2) d; with mean cost of $23,756 (±$34,441). Injury severity score mean of 3.7 (±4.6) on admission. Over 40% of the injuries to the head/thorax that were severe (AIS ≥ 3) required operative intervention (P < 0.001). CONCLUSIONS: AG injuries to the head or thorax seen at trauma centers were likely to require operative management. While no fatalities occurred, the cost was substantial. This study demonstrates pediatric injuries resulting from AG projectiles remain a significant health concern.

Wounding potential of 4.4-mm (.173) caliber steel ball projectiles.

From time to time, severe or fatal injuries caused by small caliber air rifle projectiles are seen. In forensic sciences, the theoretical wounding potential of these weapons and projectiles is widely known. Usually, shots against the skull were reported and, in these cases, penetrating the eyes or thin bone layers of the temporal region. Amongst a huge number of different projectiles available for air guns, sub-caliber 4.4-mm (.173) caliber steel ball projectiles were used in an unusual suicide case. This case led to fundamental questions concerning wound ballistics. An 82-year-old man shot once against his right temporal region and twice into his mouth with a 4.5-mm (.177) caliber air rifle. Because of the exceptionally deep penetration of the base of the skull and the use of spherical-shaped sub-caliber air rifle projectiles, terminal ballistic features were analyzed and compared to results published in forensic literature. Test shots using the same weapon and similar projectiles were fired into ballistic gelatin to measure and calculate basic wound ballistic variables of cal. 4.4-mm (.173) steel balls. In comparison, further test shots with cal. 4.5-mm (.177) steel balls BB (ball bearing), flat-headed and pointed air rifle pellets ("diabolos") were carried out. The theoretical penetration depth in solid bone was calculated with 36.4 mm, and test shots in gelatin from hard contact produced an on-average wound track of 120 mm underlining the potential wounding effect. Furthermore, spherical projectiles could roll back and forth within the barrel, and an air cushion between projectile and breechblock can reduce muzzle velocity by more than half, explaining the retained missile in the temporal region.

Image-guided percutaneous removal of ballistic foreign bodies secondary to air gun injuries.

BACKGROUND: Ballistic injuries with retained foreign bodies from air guns is a relatively common problem, particularly in children and adolescents. If not removed in a timely fashion, the foreign bodies can result in complications, including pain and infection. Diagnostic methods to identify the presence of the foreign body run the entire gamut of radiology, particularly radiography, ultrasound (US) and computed tomography (CT). Removal of the foreign bodies can be performed by primary care, emergency, surgical, and radiologic clinicians, with or without imaging guidance. OBJECTIVE: To evaluate the modalities of radiologic detection and the experience of image-guided ballistic foreign body removal related to air gun injuries within the interventional radiology department of a large pediatric hospital. MATERIALS AND METHODS: A database of more than 1,000 foreign bodies that were removed with imaging guidance by the interventional radiologists at our institution was searched for ballistic foreign bodies from air guns. The location, dimensions, diagnostic modality, duration, complications and imaging modality used for removal were recorded. In addition, the use of sedation and anesthesia required for the procedures was also recorded. RESULTS: Sixty-one patients with ballistic foreign bodies were identified. All foreign bodies were metallic BBs or pellets. The age of the patients ranged from 5 to 20 years. The initial diagnostic modality to detect the foreign bodies was primarily radiography. The primary modality to assist in removal was US, closely followed by fluoroscopy. For the procedure, 32.7% of the patients required some level of sedation. Only two patients had an active infection at the time of the removal. The foreign bodies were primarily in the soft tissues; however, successful removal was also performed from intraosseous, intraglandular and intratendinous locations. All cases resulted in successful removal without complications. CONCLUSION: Image-guided removal of ballistic foreign bodies secondary to air guns is a very effective procedure that can obviate the need for open surgical procedures in children.

Determining the behavioural dose-response relationship of marine mammals to air gun noise and source proximity.

The effect of various anthropogenic sources of noise (e.g. sonar, seismic surveys) on the behaviour of marine mammals is sometimes quantified as a dose-response relationship, where the probability of an animal behaviourally 'responding' (e.g. avoiding the source) increases with 'dose' (or received level of noise). To do this, however, requires a definition of a 'significant' response (avoidance), which can be difficult to quantify. There is also the potential that the animal 'avoids' not only the source of noise but also the vessel operating the source, complicating the relationship. The proximity of the source is an important variable to consider in the response, yet difficult to account for given that received level and proximity are highly correlated. This study used the behavioural response of humpback whales to noise from two different air gun arrays (20 and 140 cubic inch air gun array) to determine whether a dose-response relationship existed. To do this, a measure of avoidance of the source was developed, and the magnitude (rather than probability) of this response was tested against dose. The proximity to the source, and the vessel itself, was included within the one-analysis model. Humpback whales were more likely to avoid the air gun arrays (but not the controls) within 3 km of the source at levels over 140 re. 1 µPa2 s-1, meaning that both the proximity and the received level were important factors and the relationship between dose (received level) and response is not a simple one.

Energy-dependent expansion of .177 caliber hollow-point air gun projectiles.

Amongst hundreds of different projectiles for air guns available on the market, hollow-point air gun pellets are of special interest. These pellets are characterized by a tip or a hollowed-out shape in their tip which, when fired, makes the projectiles expand to an increased diameter upon entering the target medium. This results in an increase in release of energy which, in turn, has the potential to cause more serious injuries than non-hollow-point projectiles. To the best of the authors' knowledge, reliable data on the terminal ballistic features of hollow-point air gun projectiles compared to standard diabolo pellets have not yet been published in the forensic literature. The terminal ballistic performance (energy-dependent expansion and penetration) of four different types of .177 caliber hollow-point pellets discharged at kinetic energy levels from approximately 3 J up to 30 J into water, ordnance gelatin, and ordnance gelatin covered with natural chamois as a skin simulant was the subject of this investigation. Energy-dependent expansion of the tested hollow-point pellets was observed after being shot into all investigated target media. While some hollow-point pellets require a minimum kinetic energy of approximately 10 J for sufficient expansion, there are also hollow-point pellets which expand at kinetic energy levels of less than 5 J. The ratio of expansion (RE, calculated by the cross-sectional area (A) after impact divided by the cross-sectional area (A 0) of the undeformed pellet) of hollow-point air gun pellets reached values up of to 2.2. The extent of expansion relates to the kinetic energy of the projectile with a peak for pellet expansion at the 15 to 20 J range. To conclude, this work demonstrates that the hollow-point principle, i.e., the design-related enlargement of the projectiles' frontal area upon impact into a medium, does work in air guns as claimed by the manufacturers.

Modeled and Measured Underwater Sound Isopleths and Implications for Marine Mammal Mitigation in Alaska.

Before operating air guns in Alaska, industry is usually required to model underwater sound isopleths, some of which have implications for the mitigation and monitoring of potential marine mammal impacts. Field measurements are often required to confirm or revise model predictions. We compared modeled and measured air gun sound isopleths from 2006 to 2012 and found poor agreement. Natural variability in the marine environment, application of precautionary correction factors, and data interpretation in the generation of circular isopleths all contributed to the observed poor agreement. A broader understanding of the realities of modeled and measured underwater sound isopleths will contribute to improved mitigation practices.

Review of the Effects of Offshore Seismic Surveys in Cetaceans: Are Mass Strandings a Possibility?

Displacement of cetaceans is commonly reported during offshore seismic surveys. Speculation concerning possible links between seismic survey noise and cetacean strandings is available for a dozen events but without convincing causal evidence. This lack of evidence should not be considered conclusive but rather as reflecting the absence of a comprehensive analysis of the circumstances. Current mitigation guidelines are inadequate for long-range effects such as displacements and the potential for strandings. This review presents the available information for ten documented strandings that were possibly linked to seismic surveys and recommends initial measures and actions to further evaluate this potential link.

Use of Preoperation Acoustic Modeling Combined with Real-Time Sound Level Monitoring to Mitigate Behavioral Effects of Seismic Surveys.

Underwater acoustic modeling is often used to estimate the injury radius around a seismic exploration source; only occasionally has it been applied to the mitigation of behavioral effects, where the safety boundary may extend to many kilometers. Such a mitigation strategy requires precise estimation of the sound field for many source locations and likely entails field validation over the course of the operation to ensure that mitigation regions are accurate. This article reviews the enactment of such an approach for a seismic survey off Sakhalin Island and examines how similar principles may be applied to other surveys under suitable conditions.

High-Resolution Analysis of Seismic Air Gun Impulses and Their Reverberant Field as Contributors to an Acoustic Environment.

In September and October 2011, a seismic survey took place in Baffin Bay, Western Greenland, in close proximity to a marine protected area (MPA). As part of the mitigation effort, five bottom-mounted marine acoustic recording units (MARUs) collected data that were used for the purpose of measuring temporal and spectral features from each impulsive event, providing a high-resolution record of seismic reverberation persistent after the direct impulse. Results were compared with ambient-noise levels as computed after the seismic survey to evidence that as a consequence of a series of repeating seismic impulses, sustained elevated levels create the potential for masking.

Fatal laryngeal oedema in an adult from an air rifle injury, and related ballistics.

Air guns (air pistols and rifles) are already recognized as being potentially lethal. The diabolo pellet has a calibre of .177 (4.5 mm), a 1250 fps velocity, is high energetic, and is most commonly used in such weapons. In the presented case, the victim sustained an air rifle injury to the neck. The pellet passed through the thyroid cartilage, subsequently causing the extensive laryngeal swelling with haematoma around the pellet channel which fatally obstructed the airway. It is estimated microscopically that at least a number of hours must have passed from the injury to the time of death. For this case, a shooting distance was estimated by using experimental shooting values compared to physics formulas for accelerated motion. The case under question has confirmed an applicable legal approach that can be utilized by countries to classify air rifles as being as harmful as other firearms, especially those with high muzzle velocities.

Unveiling an Asymptomatic Cardiac Air-Gunshot Injury.

Interventricular septum pellet retention after air-gunshot injury in a persistently asymptomatic patient is a rare, clinically significant occurrence. Management involved monitoring, echocardiography, and computed tomography scans. After risk-benefit analysis, we favored a nonsurgical management without prophylactic antibiotics or colchicine. No post-traumatic pericarditis was observed. Patient remained asymptomatic and in excellent condition at 1-month follow-up.

Air gun accident: A case report of a penile injury.

Air rifle, although considered as a toy, can cause injuries ranging from trivial to very grievous. The severity of injuries depends on the type of air rifle, the distance of firing, and the anatomic site at which the bullet hits. We present a case involving a young boy, who was accidently hit by an air rifle while playing. The Bullet penetrated the penis through the glans to be lodged in between the distal extremities of the corpus cavernosum behind the urethra. The surgical treatment was performed and the results were good.

Forensic assessment of a life-threatening penetrating abdominal air gun injury.

Air guns are considered mostly harmless by the public opinion, but projectiles shot from common air guns can penetrate skin and thus able to cause severe, even life-threatening injury. The prevalence of air gun injuries is constantly high, but severe injuries occur rarely. Forensic evaluation of air gun injuries can be challenging since the shot wound characteristics produced by combustion in case of firearm injuries are missing. Despite these difficulties, the topic of air gun injuries is mostly overlooked in forensic literature, and there are no guidelines available which can help the assessment of specific cases. A case of an air gun injury is reported, where the projectile penetrated the abdominal wall and created multiple bowel injury. The complex assessment of all available information (macroscopic and microscopic appearance of entrance wound, types of injuries, CT findings, and crime scene reconstruction) helped to uncover the truth about the circumstances of the injury.

Asymptomatic pellet in the maxillary sinus: Medico-legal perspective.

Air guns used for plinking are weapons with a short range and low velocity. Because of their low velocity, the ammunition usually enters the body without causing any immediate life-threatening complications. Lead toxicity is a potential side effect of a pellet lodged in the body. However, there are cases where blood lead level was below the reference value even after decades of an air gun pellet remaining in the body. We report a case of 40-year-old man whose X-ray of the skull revealed a metallic foreign body that appeared to be an air gun pellet in the maxillary sinus. The patient recalled receiving a gunshot wound to his left cheek ten years ago. The wound healed, the pain subsided, and the patient was symptom-free, so he did not seek medical attention. The present case study illustrates the incidental finding of impacted foreign body and its medico-legal aspects in the Nepalese context.

Air-gun pellet at C1: a case report and literature review.

Background: Air-gun pellet injuries commonly occur in children between the age of 1-18 years old. These injuries could be fetal because it linked to injury to vital organs such as brain, heart, and eyes. In the literature, there are few studies that reported spine injury by air-gun pellet. Our case is a C1 foreign body in a pediatric patient without any neurological deficits after an air-gun injury. Case Description: A 6-year-old boy, known case of Hirschsprung disease presented to the emergency department after an air-gun injury in June 2021. On examination, the patient was hemodynamically stable, and asymptomatic. Neurological exam was intact with power 5/5 in C5-S1 and sensation 2/2 in C5-S1. Computed tomography (CT) of the cervical spine showed a foreign body at C1. After discussing the treatment options with his parents, we treat the patient conservatively by close follow-up and analgesia only. After 1 week, the patient presented to the clinic and the patient was still asymptomatic. A cervical X-ray at that time done and showed no changes in the position from the initial CT. Weekly follow-up was difficult for the family to adhere to due to their socioeconomic status. Therefore, the patient was followed up over the phone call through telemedicine at 6 months and 1 year after the injury. Conclusions: The treatment of these types on injuries is highly controversial. The treatment options could be surgical or non-surgical (conservative) such as antibiotic use. Also, there is always a debate about the choice of the treatment options.

Occupational asthma related to indoor air pollution in a worker at an indoor air gun shooting range: a case report.

Background: Indoor air pollution can cause and exacerbate asthma. We report a previously undescribed case of occupational asthma related to indoor air pollution in a worker at an indoor air gun shooting range and highlight the potential risk of developing occupational asthma in this environment. Case presentation: A 31-year-old man presented with dyspnea, cough, and sputum and was diagnosed with asthma complicated by pneumonia. Objective evidence of asthma was obtained by performing a methacholine bronchial provocation test. It was suspected that the patient had occupational asthma, which began one month after changing jobs to work within the indoor air gun shooting range. The highest peak expiratory flow (PEF) diurnal variability on working days was 15%, but the highest variation was 24%, with 4 days out of 4 weeks having a variation of over 20% related to workplace exposure. Conversely, the diurnal variability on the rest days was 7%, and no day showed a variation exceeding 20%. The difference in the average PEF between working and rest days was 52 L/min. PEF deterioration during working days and improvement on rest days were noted. Conclusions: The results obtained from the in-depth analysis of the PEF were adequate to diagnose the patient with occupational asthma. Exposure to indoor air pollution and lead and the patient's atopy and allergic rhinitis may have contributed to the development of occupational asthma.

Fluoroscopy-Guided Metallic Foreign Body Removal: A Report of Three Cases and Literature Review.

Ingested foreign objects that become trapped in the upper aerodigestive tract is a common issue that arises in Otolaryngology-Head and Neck Surgery practice. In these circumstances, it is advised to explore the neck using an external method to remove the item. However, locating the foreign body might be challenging. Not all metallic foreign body (MFB) patients require surgery, especially those without symptoms or complications. The standard X-ray and CT images are routinely examined for preoperative assessment and localization. Removal can be accomplished via flexible pharyngo-laryngoscopy or upper gastrointestinal endoscopy. Fluoroscopy is a widely accessible, minimally invasive, but underutilized tool during procedures. It offers an accurate intraoperative assessment of the foreign body in real-time. To allow the planning of a secure extraction pathway, the target should be radiopaque. In this report, we present three unique cases in which we used fluoroscopic imaging for guidance to remove a foreign body in the head and neck region in Prince Sultan Military Medical City in Riyadh, Saudi Arabia. In the first case, a young male presented with a history of foreign body sensation and odynophagia in the throat after eating a (shawarma) sandwich. In the second case, a six-year-old boy presented to the emergency department (ED) with epistaxis after being exposed to an air gun shot to his face. In the third case, a 40- year-old male presented after exposure to an air gun shot to the neck. After identification of the foreign body, all three patients were referred to Otolaryngology-Head and Neck. After radiological images have been done to confirm the presence of foreign objects, all three had a minimally invasive procedure to remove the metallic foreign bodies under fluoroscopic guidance without needing extensive surgery. All the procedures went well with no immediate complications with discharge on the same day. Fluoroscopy-guided removal of foreign bodies related to metabolic forging is a promising technique with several advantages, including real-time visualization, reduced invasiveness, and shorter recovery times. However, it is essential to weigh the benefits against the risks associated with radiation exposure and inherent limitations in detecting non-metallic objects. Further research and clinical studies are needed to optimize this technique and establish evidence-based guidelines for its application in the field of metabolic forging bodies.

The impact of seismic survey exposure on the righting reflex and moult cycle of Southern Rock Lobster (Jasus edwardsii) puerulus larvae and juveniles.

Anthropogenic aquatic noise is recognised as an environmental pollutant with the potential to negatively affect marine organisms. Seismic surveys, used to explore subseafloor oil reserves, are a common source of aquatic noise that have garnered attention due to their intense low frequency inputs and their frequent spatial overlap with coastal fisheries. Commercially important Southern Rock Lobster (Jasus edwardsii) adults have previously shown sensitivity to signals from a single seismic air gun. Here, the sensitivity of J. edwardsii juveniles and puerulus to the signals of a full-scale seismic survey were evaluated to determine if early developmental stages were affected similarly to adults, and the range of impact. To quantify impact, lobster mortality rates, dorsoventral righting reflex and progression through moult cycle were evaluated following exposure. Exposure did not result in mortality in either developmental stage, however, air gun signals caused righting impairment to at least 500 m in lobsters sampled immediately following exposure, as had previously been reported in adults with corresponding sensory system damage following exposure. Impairment resulting from close range (0 m) exposure appeared to be persistent, as previously reported in adults, whereas juveniles exposed at a more distant range (500 m) showed recovery, indicating that exposure at a range of 500 m may not cause lasting impairment to righting. Intermoult duration was (time between moults) significantly increased in juveniles exposed at 0 m from the source, indicating the potential for slowed development, growth, and physiological stress. These results demonstrate that exposure to seismic air gun signals have the potential to negatively impact early life history stages of Southern Rock Lobsters. The similarity of both the impacts and the sound exposure levels observed here compared to previous exposure using a single air gun offer validation for the approach, which opens the potential for accessible field-based experimental work into the impact of seismic surveys on marine invertebrates.