U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
U.S. Navy Space and Naval Warfare Systems Center Pacific, 53475 Strothe Rd., San Diego, CA, 92152, USA.
Environ Monit Assess. 2018 Feb 24;190(3):171. doi: 10.1007/s10661-018-6558-x.
Munition constituents (MC) are present in aquatic environments throughout the world. Potential for fluctuating release with low residence times may cause concentrations of MC to vary widely over time at contaminated sites. Recently, polar organic chemical integrative samplers (POCIS) have been demonstrated to be valuable tools for the environmental exposure assessment of MC in water. Flow rate is known to influence sampling by POCIS. Because POCIS sampling rates (R) for MC have only been determined under quasi-static conditions, the present study evaluated the uptake of 2,4,6-trinitrotoluene (TNT), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and 2,4- and 2,6-dinitrotoluenes (DNT), by POCIS in a controlled water flume at 7, 15, and 30 cm/s in 10-day experiments using samplers both within and without a protective cage. Sampling rate increased with flow rate for all MC investigated, but flow rate had the strongest impact on TNT and the weakest impact on RDX. For uncaged POCIS, mean R for 30 cm/s was significantly higher than that for 7 cm by 2.7, 1.9, 1.9, and 1.3 folds for TNT, 2,4-DNT, 2,6-DNT, and RDX, respectively. For all MC except RDX, mean R for caged POCIS at 7 cm/s were significantly lower than for uncaged samplers and similar to those measured at quasi-static condition, but except for 2,6-DNT, no caging effect was measured at the highest flow rate, indicating that the impact of caging on R is flow rate-dependent. When flow rates are known, flow rate-specific R should be used for generating POCIS-derived time-averaged concentrations of MC at contaminated sites.
弹药成分 (MC) 存在于世界各地的水生环境中。由于潜在的释放波动和停留时间短，受污染地点的 MC 浓度可能会随时间发生广泛变化。最近，极性有机化学整合采样器 (POCIS) 已被证明是评估水中 MC 环境暴露的有用工具。流速已知会影响 POCIS 的采样。由于仅在准静态条件下确定了 MC 的 POCIS 采样率 (R)，因此本研究在 7、15 和 30 cm/s 的控制水水槽中评估了 2,4,6-三硝基甲苯 (TNT)、RDX（六氢-1,3,5-三硝基-1,3,5-三嗪）以及 2,4-和 2,6-二硝基甲苯 (DNT) 通过 POCIS 的吸收，实验使用了带有和不带有保护笼的采样器，为期 10 天。对于所有研究的 MC，采样率随流速增加而增加，但流速对 TNT 的影响最强，对 RDX 的影响最弱。对于无笼 POCIS，30 cm/s 的平均 R 分别比 7 cm/s 的 R 高 2.7、1.9、1.9 和 1.3 倍，分别用于 TNT、2,4-DNT、2,6-DNT 和 RDX。对于除 RDX 以外的所有 MC，7 cm/s 笼式 POCIS 的平均 R 明显低于无笼采样器，与准静态条件下测量的 R 相似，但除 2,6-DNT 外，在最高流速下未测量到笼式效应，表明笼式对 R 的影响取决于流速。当流速已知时，应使用流速特定的 R 来生成受污染地点的 POCIS 衍生的 MC 时间平均浓度。
