Degradation of RDX and HMX in contaminated sludge and water with indigenous microbes isolated from an explosive contaminated site

Abstract

Explosives are simply defined as substances that, when subjected to chemical and thermal shock, produce a significant amount of heat, gas, radiation, and shock waves [1,2]. Due to the various advantages, they offer, explosives have garnered a lot of attention over the years. Humans have used explosives for a variety of purposes, such as cannon propellant, mining, defense, and rocket propulsion. During testing, manufacturing, transport, and use of these explosives their contamination in the environment has increased significantly. A high amount of RDX and HMX contamination in soil and water has been observed all over the world [3–7]. Nearly, 1900 mg/kg and 900 mg/kg of RDX and HMX were present in the soil at the Louisiana Army Ammunition plant [8]. It was also observed that up to 3 mg/L of HMX concentration was present in the wastewater effluent [9]. RDX and HMX contamination can be a major threat to the environment and humans. Both RDX and HMX are toxic to humans; they can cause seizures, convulsions, a decrease in body weight, neuromuscular toxicity, dilation of kidney tubules, liver lesions, etc., [10–15]. United states environmental protection agency (USEPA) has categorized RDX as a group ‘C’ carcinogen [16]. According to Agency for Toxic Substances and Disease Registry, USA, animal studies suggested RDX causes neurological, reproductive, and kidney damage [17]. However, HMX is classified as non-carcinogenic to humans but can cause convulsions, histopathological liver lesions, dilation of kidney tubules, mydriasis, change in body mass, etc. in mammals [15,18,19]. As both the RDX and HMX are toxic to the environment there is a need to remediate the contaminated sites.