Revision as of 00:20, 18 October 2014

Exeter | ERASE

The Problem

TNT has been used as an explosive since 1902, and quickly became widely used in warfare and demolition; in World War II over one million tonnes was produced by the Allies alone. Although production has fallen since then over 1000 tonnes per annum are produced just by the USA.

There are consequences to this high level of production. The waste created when producing TNT is toxic and long-lasting; the soil around a World War I ammunition disposal facility in Belgium was found to still contain high levels of TNT and related compounds.

What implications does TNT have for health?

Chronic exposure to TNT can put the sufferer at an increased risk of leukaemia. In Marburg, Germany, residents living close to contaminated ground soil from a WWII ammunition plant were 10 times more likely to die of leukaemia than the national average. A study conducted on copper miners who used TNT in their work found they were 4.5 times more likely to develop urinary tract tumours and 14.3 times more at risk of kidney tumours. This mutagenic effect has also been observed in mice.
Prolonged TNT exposure can cause cataracts. An Israeli study showed that 50% of people had developed the illness after 7 years exposure on average. In a Chinese study that tracked munitions workers who had been exposed to TNT for 20 years, 88.4% of the workers had developed peripheral cataracts.
Acute exposure to TNT results in a 1-8% increase in methemoglobin levels in the blood. This can last for 2-5 days. Methemoglobin is dangerous as it is unable to bind oxygen – meaning that oxygen cannot be released into the blood and can result in tissue hypoxia.

There have also been multiple studies in animals that show TNT can cause:

Negative effects on fertility
Development of dermatitis
Anaemia
Spleen damage

How does TNT pollution occur?

Exposure to TNT occurs in many places across the world. The main cause of TNT pollution is through waste created at TNT production sites. A significant level of pollution is also created through military exercises and mining activites. There are hundreds of TNT polluted sites in America alone , with thousands of sites worldwide.

TNT Production/Disposal facilities present such a threat to health due to the lack of regulation and care taken in the past when working with these compounds; common practice around the world was to allow all “pink water”, heavily contaminated waste water produced during the creation of TNT, to run off into lagoons built into the environment. Current TNT production facilities do not pose a significant threat to health, due to higher safety standards.

The legacy of TNT pollution is widespread:

In Germany, an ammunition factory from WWII produced over 5 million litres of TNT. This resulted in polluted ground water, and there is a risk to health which must be dealt with by the water treatment plant.
Closer to home, England was supplied by 12 munitions factories during WWI and another 16 in WWII, all producing toxic TNT waste. In addition to this during the wars many bombs containing TNT-based explosives were dropped on the country; in one year alone during WWII this accounted for approximately 100 tons of TNT.
Unused munitions are difficult to dispose of. This has resulted in dumping sites. At Beaufort’s Dyke, Scotland, over 1 million tons of used munitions have been dumped into the ocean. Many of these munitions are contaminated with explosives and risk causing exposure to these compounds around the Scottish coastline. There are a further 9 smaller-scale dumping sites in Scotland and another 12 in England.

Current Methods

Current methods of degradation rely on incineration of waste. However, this is impractical as toxic ash and other dangerous chemicals are produced. This is also very expensive.

Some techniques also rely on the use of naturally occurring bacteria that are capable of degradation in a controlled situation such as a composting or bio-slurry plant to cleanse large areas of soil.

In our project we hope to improve this process by synthesising our own bacteria with more effective degradation abilities – meaning faster degradation with non-toxic bi-products and the potential for kill switches and fluorescent markers. There is also the added benefit that we can include proteins that will allow the degradation of other explosives, which can also pose less severe health risks.