The industrial use and widespread application of carbon-based nanomaterials have caused a rapid increase in their production over the last decades. However, toxicity of these materials is not fully known and is still being investigated for potential human and ecological health risks. Detecting carbon-based nanomaterials in the environment using current analytical methods is problematic, making environmental fate and transport modeling a practical way to estimate environmental concentrations and assess potential ecological risks. The Water Quality Analysis Simulation Program 8 (WASP8) is a dynamic, spatially resolved fate and transport model for simulating exposure concentrations in surface waters and sediments. Recently, WASP has been updated to incorporate processes for simulating the fate and transport of nanomaterials including heteroaggregation and phototransformation. This study examines the fate and transport of multiwalled carbon nanotubes (MWCNT), graphene oxide (GO) and reduced graphene oxide (rGO) in four aquatic ecosystems in the southeastern United States. Sites include a seepage lake, a coastal plains river, a piedmont river and an unstratified, wetland lake. A hypothetical 50-year release is simulated for each site-nanomaterial pair to analyze nanomaterial distribution between the water column and sediments. For all nanomaterials, 99% of the mass loaded moves though systems of high and low residence times without being heteroaggregated and deposited in the sediments. However, significant accumulation in the sediments does occur over longer periods of time. Results show that GO and rGO had the highest mass fraction in the water column of all four sites. MWCNT were found predominantly in the sediments of the piedmont river and seepage lake but were almost entirely contained in the water column of the coastal plains river and wetland lake. Simulated recovery periods following the release estimate 37+ years for lakes and 1-4 years for rivers to reduce sediment nanomaterial concentrations by 50% suggesting that carbon-based nanomaterials have the potential for long-term ecological effects.

中文翻译：

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多壁碳纳米管和氧化石墨烯在不同水生生态系统中的环境归宿

在过去的几十年中，碳基纳米材料的工业应用和广泛应用导致其产量迅速增加。然而，这些材料的毒性尚不完全清楚，仍在调查潜在的人类和生态健康风险。使用当前的分析方法检测环境中的碳基纳米材料是有问题的，这使得环境归宿和运输建模成为估计环境浓度和评估潜在生态风险的实用方法。水质分析模拟程序 8 (WASP8) 是一个动态的、空间解析的归宿和传输模型，用于模拟地表水和沉积物中的暴露浓度。最近，WASP 已更新以纳入模拟纳米材料的命运和运输的过程，包括异质聚集和光转化。本研究调查了美国东南部四个水生生态系统中多壁碳纳米管 (MWCNT)、氧化石墨烯 (GO) 和还原氧化石墨烯 (rGO) 的命运和运输。站点包括渗流湖、沿海平原河、山前河和未分层的湿地湖。模拟每个场地-纳米材料对的假设 50 年释放，以分析水柱和沉积物之间的纳米材料分布。对于所有纳米材料，99% 的质量负载通过高停留时间和低停留时间的系统移动，而不会杂聚并沉积在沉积物中。然而，沉积物中的大量积累确实发生在较长时期内。结果表明，GO 和 rGO 在所有四个位点的水柱中具有最高的质量分数。MWCNT主要存在于山前河和渗流湖的沉积物中，但几乎全部包含在沿海平原河流和湿地湖的水体中。湖泊释放估计 37 年以上，河流 1-4 年释放后的模拟恢复期，将沉积物纳米材料浓度降低 50%，表明碳基纳米材料具有产生长期生态效应的潜力。MWCNT主要存在于山前河和渗流湖的沉积物中，但几乎全部包含在沿海平原河流和湿地湖的水体中。湖泊释放估计 37 年以上，河流 1-4 年释放后的模拟恢复期，将沉积物纳米材料浓度降低 50%，表明碳基纳米材料具有产生长期生态效应的潜力。MWCNT主要存在于山前河和渗流湖的沉积物中，但几乎全部包含在沿海平原河流和湿地湖的水体中。湖泊释放估计 37 年以上，河流 1-4 年释放后的模拟恢复期，将沉积物纳米材料浓度降低 50%，表明碳基纳米材料具有产生长期生态效应的潜力。