Monteil-Rivera Fanny, Paquet Louise, Giroux Romain, Hawari Jalal
Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montréal, Québec, Canada.
J Environ Qual. 2008 May 2;37(3):858-64. doi: 10.2134/jeq2007.0451. Print 2008 May-Jun.
Sinking of military ships, dumping of munitions during the two World Wars, and military training have resulted in the undersea deposition of numerous unexploded ordnances (UXOs). Leaching of energetic compounds such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from these UXOs may cause adverse ecological effects so that the long-term fate of these chemicals in the sea should be known. The present study assesses the contribution of alkaline hydrolysis into the natural attenuation of RDX and HMX in coastal waters. Alkaline hydrolysis rates were shown to be unaffected by the presence of sodium chloride, the most common component in marine waters. Kinetic parameters (E(a), ln A, k(2)) quantified for the alkaline hydrolysis of RDX and HMX in deionized water (30-50 degrees C, pH 10-12) agreed relatively well with abiotic degradation rates determined in sterilized natural coastal waters (50 and 60 degrees C, variable salinity) even if the latter were generally slightly faster than the former. Furthermore, similar products (HCHO, NO(2)(-), O(2)NNHCH(2)NHCHO) were obtained on alkaline hydrolysis in deionized water and abiotic degradation in coastal waters. These two findings suggested that degradation of nitramines in sterilized natural coastal waters, away from light, was mainly governed by alkaline hydrolysis. Kinetic calculations using the present parameters showed that alkaline hydrolysis of RDX and HMX in marine waters at 10 degrees C would respectively take 112 +/- 10 and 2408 +/- 217 yr to be completed (99.0%). We concluded that under natural conditions hydrolysis should not contribute significantly to the natural attenuation of HMX in coastal waters whereas it could play an active role in the natural attenuation of RDX.
两次世界大战期间军舰沉没、弹药倾倒以及军事训练导致大量未爆炸弹药（UXO）沉入海底。这些未爆炸弹药中六氢-1,3,5-三硝基-1,3,5-三嗪（RDX）和八氢-1,3,5,7-四硝基-1,3,5,7-四氮杂环辛烷（HMX）等含能化合物的浸出可能会造成不利的生态影响，因此有必要了解这些化学物质在海洋中的长期归宿。本研究评估了碱性水解对沿海水域中RDX和HMX自然衰减的贡献。结果表明，碱性水解速率不受海水中最常见成分氯化钠存在的影响。在去离子水中（30 - 50℃，pH 10 - 12）对RDX和HMX碱性水解进行量化的动力学参数（E(a)、ln A、k(2)）与在经过灭菌的天然沿海水域（50和60℃，盐度可变）中测定的非生物降解速率相对吻合，即便后者通常比前者略快。此外，在去离子水中碱性水解以及在沿海水域非生物降解过程中都得到了类似的产物（HCHO、NO(2)(-)、O(2)NNHCH(2)NHCHO）。这两个发现表明，在无光条件下经过灭菌的天然沿海水域中硝胺的降解主要受碱性水解控制。使用当前参数进行的动力学计算表明，海水中10℃时RDX和HMX的碱性水解分别需要112±10年和2408±217年才能完成（99.0%）。我们得出结论，在自然条件下，水解对沿海水域中HMX的自然衰减贡献不大，而对RDX的自然衰减可能起到积极作用。
