Introductory Remarks

Engineered nanomaterials (ENMs) used as fertilizers, pesticides and growth regulators will involve direct application of large quantities of ENMs to the environment and products intended for human consumption. Assessing their life cycle environmental impacts to mitigate unintended consequences poses several challenges in areas such as (1) definition of functional units that represent the function provided by nano-enabled agrochemicals (2) availability of comprehensive data necessary to inform life cycle material flow for inventory development specific to this application, (3) human and environmental exposure and effects data relevant to the agricultural context for impact assessment models, (4) identification of spatial and temporal dependent components that can affect results, and (5) data uncertainties and the possibility of their reduction through collaborative efforts between life cycle practitioners and experimental researchers using anticipatory decision-based models. While several of these challenges are experienced in LCA of emerging technologies generally, there is heightened relevance with respect to the utilization of ENMs in agriculture. Early application of LCA to this emerging technology can assist in identifying areas that can be further improved to enhance overall environmental benefits. One of the proposed benefits of nano-enabled agrochemicals is reducing our reliance on conventional fertilizers. A life cycle energy analysis of common ENMs used as agricultural supplements recommends the need for lower ENM doses than what the literature suggests, to at least break even with the current fertilization methods on an energy stand point. A more immediate advantage realized through lowering fertilizer use is reduction in eutrophication potential, however, a net benefit is only attainable if releases of nitrogen and phosphorous from upstream production stages do not outweigh the downstream savings. As research on the agricultural application of ENMs progresses, more information on their behavior and effects becomes available, allowing for assessment of other environmental impact categories. Findings from these analyses can inform research prioritization to ensure safe and sustainable design, development, and implementation of nano-enabled agrochemicals.