In October 2008, the US Environmental Protection Agency (US EPA) released a fact sheet providing an overview on the use of nanotechnology in environmental remediation (US EPA Fact Sheet, 2008). Because of their increased reactivity due to smaller size and larger surface area, nanomaterials are gaining prominence for in situ remediation or sequestration of chlorinated solvents (TCE, PCE), PCBs, DNAPL, and heavy metals (chromium). Thus, the full-scale field testing of this technology has been increasing significantly in an effort to develop this potentially more effective and economical remedial technique.
Gautham Jegadeesan, Ph.D, an expert in the use of nanomaterials for remediation and who recently joined Gradient Corporation as an Environmental Engineer stated, "It is estimated that the production of specific nanomaterials for environmental remediation will increase drastically in the next decade, largely due to their unique functionalities. In fact, the most recent advances in nanomaterial technology have been the ability to design and produce materials that are geared for specific remedial solutions and also eliminate the generation of undesirable remediation byproducts, which can occur with most macro-scale materials." Dr. Jegadeesan's specific expertise includes the characterization and evaluation of engineered nanomaterials for environmental remediation, and analysis of their fate and transport in the environment. His work has shown that compared to traditional technologies, bimetallic nanomaterials, nZVI, and nano-titanium oxide can greatly enhance contaminant removal.
Fate, Transport, and Toxicity Issues
As promising as the site remediation applications of nano-sized materials and structures are, there are several unanswered questions relating to their potential toxicity, and whether their transport, potential transformation, and fate in the environment could potentially result in elevated risk to ecosystems and human health. The same unique functionalities that make nanomaterials so attractive for contaminant remediation could make them potentially harmful under some circumstances. "Since the nanomaterial can travel longer distances in the environment due to their size compared to their macro-sized counterparts, can they also transport contaminants attached to them during the sequestration process over such distances? If so, the consequence of such a mechanism could be a toxic effect from either the nanomaterials themselves, the contaminant, or, in a synergistic way, a combination of both, not at the contaminated site but at a location away from the site," Jegadeesan said. "In addition, tailoring the nanomaterials for specific remedial applications has added additional variables in the hierarchy of unknowns on nanomaterial toxicity and risks." For all these reasons, case-by-case fate, transport, and risk assessments should be considered when using these materials for remedial purposes.
Addressing Nanotechnology Risk Issues
Led by Dr. Barbara D. Beck and Dr. Christopher M. Long, Gradient’s Nanotechnology Risk practice has experience in addressing the potential human health and ecological impacts of engineered nanomaterials. In fact, Gradient has prior experience conducting a qualitative risk assessment for the use of nZVI in the remediation of TCE in groundwater. With the addition of Dr. Jegadeesan's experience in nanotechnology fate and transport to Gradient's strong capabilities in nanomaterial