Fireworks, the one and only amongst all other pyrotechnic applications, have pleased the hearts and minds of billions of people all over the world for almost 1000 years. Even though pyrotechnics were originally developed in order to fulfil the needs of military purposes, fireworks began to form a unique part of the cultural heritage of many countries, presumably starting in ancient China during the Song Dynasty (960–1280 AD). Festivities like New Year's Eve, national holidays or activities like music festivals and parish fairs are crowned by a firework display. Fireworks have traditionally been associated with Independence Day celebrations, like 4 July in the United States, Guy Fawkes' Night (5 November) in Britain, or Bastille Day (14 July) in France. Much of Chinese culture is associated with the use of firecrackers to celebrate the New Year and other important occasions. The fascination of fireworks and firecrackers is due to the brilliant colours and booming noises, which have a universal appeal to our basic senses [1].

The basic components of any traditional civil firework is black powder, a mixture of about 75% potassium nitrate, 15% charcoal, and about 10% sulfur [2]. Without the addition of a colouring agent, the fuel would provide an almost white light. Therefore, several metal salts can be added to cause colourful luminescence upon combustion. In general barium is used to obtain a green coloured flame, strontium for red, copper for blue and sodium for yellow [2, 3].

The use of pyrotechnics has raised issues pertaining to health concerns. The health aspects are not only restricted to injuries by accidental ignition of certain devices. Moreover, several recent works identified fireworks and pyrotechnics as causing environmental pollution, which might result in a potential hazard concerning health aspects. The fundamental problem in this respect is that all chemicals used are dispersed in the environment by combustion. This includes both reaction products and unburnt constituents of a pyrotechnic mixture. One major environmental concern in pyrotechnics focuses on the emission of heavy metals. This is the topic discussed in the article by Georg Steinhauser and Andreas Musilek in this issue [4]. A possible interrelationship between respiratory effects and fireworks emissions of barium-rich aerosols was also raised last year [5].

In recent years the potential hazard of naturally occurring radioactive material has become of importance to the scientific community. Naturally occurring radionuclides can be of terrestrial or cosmological origin. Terrestrial radionuclides were present in the presolar cloud that later contracted in order to build our solar system. These radionuclides—mainly heavy metals—and their non-radioactive isotopes are nowadays fixed in the matrix of the Earth's structure. Usually, their percentage is quite small compared to their respective stable isotopes—though there are exceptions like in the case of radium. The problem with environmental pollution due to naturally occurring radioactive material begins when this material is concentrated due to mining and milling, and later further processed [6].

Environmental pollution due to radioactive material goes back as far as the Copper and Iron Ages, when the first mines were erected in order to mine ores (gold, silver, copper, iron, etc), resulting in naturally occurring radioactive material being set free with other dusts into the atmosphere.

So where is the link between pyrotechnics and radioactivity? In this article presented by Georg Steinhauser and Andreas Musilek [4], the pyrotechnic ingredients barium nitrate and strontium nitrate are explored with respect to their chemical similarities to radium. The fundamental question, therefore, was whether radium can be processed together with barium and strontium. If so, the production and ignition of these pyrotechnic ingredients could cause atmospheric pollution with radium aerosols, resulting in potential negative health effects, unless an extensive purification of the ores is undertaken.

From the environmental and toxicological point of view, the formation of barium-rich aerosols following the display of fireworks is a problem. The barium compounds released are mainly in a bioavailable form. Considering the chemical similarities of barium and strontium to radium, the potential hazard of fireworks due to liberated radionuclides might be of interest. Ores and compounds used for pyrotechnic devices are usually purified only to the grade that is necessary for the intended effect. Thus, fireworks can contain traces of heavy metals which do not have a pyrotechnic function [5, 7, 8]. The incorporation, and thus, the inhalation of α-emitters (such as ²²⁶Ra) is a major health issue in human radiation protection. In order to examine the potential hazard Georg Steinhauser and Andreas Musilek investigated this topic.

Although the specific radium activities were relatively low in the investigated samples, Steinhauser and Musilek showed that radium is significantly enriched in pyrotechnics. This fact gives no reason why people should not attend firework displays or should not set off their own fireworks on New Year's Eve. Rather, it is now the authorities' turn to take care of this topic. What if highly active radiobarite was used as a raw material for the production of pyrotechnic indoor devices? This would definitely cause unexpected health issues. Now that the problem is identified, the authorities have to ensure that the exemption limits are not exceeded.

Today, public opinion is going more and more in the direction of using eco-friendly products. A lot of products have been shown to have potential negative health effects and are therefore now produced in safer and more eco-friendly forms than they used to be a few years ago.

Thus, Georg Steinhauser and Andreas Musilek demonstrated that pyrotechnics do contain a certain amount of radioactive material—so why not make pyrotechnics safer, more eco-friendly and 'greener'?

References

[1] Plimpton G 1984 Fireworks: A History and Celebration (New York: Doubleday)

[2] Russell M S 2000 The Chemistry of Fireworks (Cambridge: Royal Society of Chemistry)

[3] Steinhauser G and Klapötke T M 2008 'Green' pyrotechnics: a chemist's challenge Angew. Chem. Int. Ed. 47 3330–47

[4] Steinhauser G and Musilek A 2009 Do pyrotechnics contain radium? Environ. Res. Lett. 4 034006

[5] Steinhauser G, Sterba J H, Foster M, Grass F and Bichler M 2008 Heavy metals from pyrotechnics in New Year's Eve snow Atmos. Environ. 42 8616–22

[6] Cooper J R, Randle K and Sokhi R S 2003 Radioactive Releases in the Environment—Impact and Assessment (Chichester: Wiley)

[7] Smith R M and Dinh V-D 1975 Changes in forced expiration flow due to air pollution from fireworks Environ. Res. 9 321–31

[8] Bach W, Dickinson L, Weiner B and Costello G 1972 Some adverse health effects due to air pollution from fireworks Hawaii Med. J. 31 459–65