Helseeffekter ved bruk av blyholdig og blyfri ammunisjon i kombinasjon med HK416

Background: Smoke emitted during firing of small arms consists of a mixture of gases, particles and aerosols. The purpose of this study was to study the acute effects using HK416 and three ammunition types SS109, NM229 and NM255 by checking symptoms, measuring lung function and inflammatory markers in blood as well as effects on cells from the central airways before and after shooting. In addition, it should be examined whether there were differences in effects and response between the three different types of ammunition. Methods: 55 healthy, non-smoking employees in the military and FFI (age 19-62, mean 40 years) were recruited and divided randomly into three groups, one for each type of ammunition. The subjects were examined 3-14 days before shooting, including lung function (spirometry, gas diffusion, exhaled NO and methacholine test) and sampling of blood and sputum. Immediately after shooting symptoms were reported, spirometry and NO in exhalation air were measured, and blood samples were taken. 24 hours after firing lung function measurements were repeated as before shooting, new blood samples were taken and symptoms experienced the last day were reported. Two days after the shooting, samples of induced sputum were collected. During firing all subjects were placed in a semi-airtight tent for 60 minutes. The standard weapon in the Norwegian Armed Forces (HK416, Heckler & Koch) was used with three different types of ammunition: leaded ammunition (SS109) (n = 17), lead-free ammunition (NM229) (n = 19) and a modified lead-free ammunition (NM255) (n = 19). Results: 54 out of 55 subjects reported symptoms after shooting. 42 of 55 reported general symptoms such as fever and malaise, and 45 of 55 reported respiratory symptoms such as cough and discomfort in the respiratory tract. General symptoms started 3-12 hours after exposure with a few exceptions (2 of 43). The symptoms resolved within 65 hours. The duration of the general symptoms was less than 24 hours for most subjects. The duration of airway symptoms varied. Lung function was statistically significantly decreased immediately after the shooting and the day after the shooting. There was no statistically significant difference between the ammunition types. Most subjects (52 of 55) had elevated levels of the inflammatory markers CRP, the total number of white blood cells and neutrophils in the blood one day after shooting, as well as increased levels of neutrophils in sputum two days after the shooting. The three types of ammunition were all able to produce the reported health effects. Discussion and Conclusion: The reported symptoms, and inflammatory markers are consistent with the development of metal fume fever. However many of the shooters also reported respiratory irritation not consistent with metal fume fever (symptoms that appear at the time of exposure). The symptoms disappeared in general within 24 hours, while inflammatory markers persisted at least for 48 hours. It is known that metal fever and respiratory irritation can be caused by metallic fine dust or fumes. The elevated values of copper and zinc in airborne dust are possible candidates to explain the observed symptoms and findings, which are supported by a positive correlation between zinc and elevated levels of white blood cells. All types of ammunition used in combination with HK416 led to the described health effects. Repeated exposure at levels causing acute symptoms long-term effects cannot be excluded.