Environet, Inc., 1286 Queen Emma Street, Honolulu, Hawaii 96813, USA.
Environ Sci Process Impacts. 2013 Oct;15(11):2023-9. doi: 10.1039/c3em00320e.
A nine-month in situ bioremediation study was conducted in Makua Military Reservation (MMR) in Oahu, Hawaii (USA) to evaluate the potential of molasses to enhance biodegradation of royal demolition explosive (RDX) and high-melting explosive (HMX) contaminated soil below the root zone. MMR has been in operation since the 1940's resulting in subsurface contamination that in some locations exceeds USEPA preliminary remediation goals for these chemicals. A molasses-water mixture (1 : 40 dilution) was applied to a treatment plot and clean water was applied to a control plot via seven flood irrigation events. Pore water samples were collected from 12 lysimeters installed at different depths in 3 boreholes in each test plot. The difference in mean concentrations of RDX in pore water samples from the two test plots was very highly significant (p < 0.001). The concentrations differences with depth were also very highly significant (p < 0.001) and degradation was greatly enhanced at depths from 5 to 13.5 ft. biodegradation was modeled as first order and the rate constant was 0.063 per day at 5 ft and decreased to 0.023 per day at 11 ft to 13.5 ft depth. Enhanced biodegradation of HMX was also observed in molasses treated plot samples but only at a depth of 5 ft. The difference in mean TOC concentration (surrogate for molasses) was highly significant with depth (p = 0.003) and very highly significant with treatment (p < 0.001). Mean total nitrogen concentrations also differed significantly with treatment (p < 0.001) and depth (p = 0.059). The molasses water mixture had a similar infiltration rate to that of plain water (average 4.12 ft per day) and reached the deepest sensor (31 ft) within 5 days of application. Most of the molasses was consumed by soil microorganisms by about 13.5 feet below ground surface and treatment of deeper depths may require greater molasses concentrations and/or more frequent flood irrigation. Use of the bioremediation method described herein could allow the sustainable use of live fire training ranges by enhancing biodegradation of explosives in situ and preventing them from migrating to through the vadose zone to underlying ground water and off-site.
在夏威夷瓦胡岛的马夸军事保留区（MMR）进行了为期九个月的原位生物修复研究，以评估糖蜜增强受皇家拆除炸药（RDX）和高熔点炸药（HMX）污染土壤生物降解的潜力，这些土壤位于根区以下。MMR 自 20 世纪 40 年代以来一直在运行，导致地下污染在某些地点超过了美国环保署对这些化学物质的初步修复目标。将糖蜜-水混合物（1：40 稀释）施用于处理区，并用清水施用于对照区，通过七次洪水灌溉事件进行。从每个试验区的 3 个钻孔中的 12 个渗流计中收集了孔隙水样品。两个试验区的孔隙水样品中 RDX 的平均浓度差异非常显著（p < 0.001）。浓度随深度的差异也非常显著（p < 0.001），在 5 至 13.5 英尺的深度降解得到极大增强。生物降解被建模为一级反应，在 5 英尺处的速率常数为每天 0.063，在 11 英尺至 13.5 英尺深度处降低至每天 0.023。在糖蜜处理的试验区样品中也观察到 HMX 的生物降解增强，但仅在 5 英尺的深度。TOC 浓度（糖蜜的替代物）的平均值随深度（p = 0.003）和处理（p < 0.001）高度显著。总氮浓度也随处理（p < 0.001）和深度（p = 0.059）显著不同。糖蜜水混合物的入渗率与清水相似（平均每天 4.12 英尺），并在施用后 5 天内到达最深的传感器（31 英尺）。大部分糖蜜在地下 13.5 英尺以下被土壤微生物消耗，而对更深层的处理可能需要更高的糖蜜浓度和/或更频繁的洪水灌溉。使用本文所述的生物修复方法可以通过增强现场爆炸物的生物降解并防止它们迁移到包气带以下的地下水和场外来允许可持续使用实弹训练区。
