Phytoremediation of Toxic Explosives

Abstract

Widespread contamination of the environment by explosives resulting from the manufacture, disposal and testing of munitions is becoming a matter of increasing concern. Most explosives are considered to be a major hazard to biological systems due to their toxic and mutagenic effects. Interest on the bioremediation of lands contaminated with explosives has recently been focused on phytoremediation. Unfortunately, whilst plants have many advantages for the remediation of contaminated land and water, they lack the catabolic versatility which enables microorganisms to mineralize such a wide diversity of xenobiotic compounds. This raised the interesting question as to whether the impressive biodegradative capabilities of soil bacteria could be combined with the high biomass and stability of plants to yield an optimal system for in situ bioremediation of explosive residues in soil. During the last few years, plants have been genetically modified to overcome the inherent limitation of plant detoxification capabilities, following a strategy similar to the development of transgenic crops. Bacterial genes encoding enzymes involved in the breakdown of explosives have been introduced in higher plants, resulting in significant enhancement of plant tolerance, uptake and detoxification performances. Transgenic plants exhibiting biodegradation capabilities of microorganisms bring the promise of an efficient and environmental-friendly technology for cleaning up polluted soils.