NC1187: The Chemical and Physical Nature of Particulate Matter Affecting Air, Water and Soil Quality. (NCR174)
Statement of Issues and Justification
A. The need as indicated by stakeholders. Agricultural practices affect air, soil, and water quality for both rural and urban communities. The impacts flow both ways. Activities in urban settings affect soil and water quality for rural and agricultural use, while public concern and regulatory authority to protect the environment impel efforts to preserve and improve environmental quality. Efficient management and effective regulation will optimize environmental and health protection without crippling the economy, rural or urban. The focus of Multistate Project NC-1022 is the behavior of particulate matter in size ranges capable of movement through air and water. Although this encompasses sizes from silt (2 - 50 µm) to the sub-micrometer range, never has the importance of assessing the impact of nanoparticles been so important. A 2003 report to CSREES from a National Planning Workshop outlines the potential benefits of nanotechnology to agriculture and food systems. Two of the concerns of the report, however, are (1) the potential for a backlash from the public similar to what has happened with genetic engineering and (2) a lack of knowledge of the environmental behavior of nanoparticles (Scott and Chen, 2003). The report states: Novel materials developed through materials science and engineering are critical to the advancement of agriculture and food systems. Natural nanoparticles in soil, water, and air must be understood to the point that their characteristics and behavior can be controlled so that this natural resource may be more fully utilized. Agricultural practices also create and disperse nanoparticles. The environmental abundance of nanoparticles produced by agriculture must be understood and any negative effects mitigated. Echoing this view is that of numerous government, industry, environmental and academic leaders from DuPont and Environmental Defense and committees of the Science Council of Japan and the British Royal Society. These and others have called for extensive research on identifying and assessing the potential risks of nanomaterials to human health and the environment. {Service, 2005}According to the National Science Foundation, nanotechnology will have a $1 trillion impact on the global economy while, at the time of the article, less than $46 million has gone to studies of nanomaterials impact on health and the environment from the largest funding sources--U.S. federal sources and the European Community. The agricultural research community should take a lead role in such research. Not only are agricultural and food systems poised to benefit from nanotechnology, but have the research expertise and infrastructure in the land grant university system to determine the risks and benefits of nanoparticles. Project NC-1022 has been able to extend that expertise and infrastructure to national user facilities that make state of the art instrumentation and computer power available to our focus on particulate matter in air, soil, and water. Continuing this project will allow us to reap the benefits of the contacts we have established and expertise we have gained in the past. B. The importance of the work and the consequences if not done. The reactivity of soils with respect to plant nutrient elements and environmental toxins is to a very great extent dependent on reactions that involve particles with diameters of tens of micrometers or less (silt, clays, microbes, nanoparticles). Because these fine particles in soils are contained in a very complex mixture it is often impossible to gain a mechanistic understanding of processes governing the retention and mobility of many chemical species in soils by traditional techniques. For example, it is well known that the phosphorus is associated with fine particles (Hanley and Murphy, 1970), but the exact chemistry of these particles is not well understood. Recent work has demonstrated the utility of synchrotron x-ray microprobe spectroscopy for the study of the chemistry of P in the fine fraction of soils (Bloom, personal communications 2009). Copper, zinc and lead are enriched in the fine fraction of soil and the particle size is an important factor for the bioaccessibility of these elements (Madrid et al., 2008). A mechanistic understanding of the role of particle size in mobility and bioaccessibility will require a detailed understanding of the chemistry of soil particles at a scale that is only possible using advanced spectroscopic and microscopic instruments. Recently questions concerning the environmental fate of nanoparticles arising from agricultural operations and from the manufacture, use or disposal of consumer products has arisen. Little is known about the toxicology and environmental behavior of these particles. These particles are very difficult to study because the particles are < 100 nm. The NC-1022 group is well poised to address the problems presented by the analytical difficulties that nanoparticles present. Our current access to synchrotron sources and the cooperation that has developed among members will serve to help solve the difficult problem of completely characterizing nanoparticles with a focus on their environmental and agricultural impact. Without the combined efforts of the NC_1022 membership, agricultural research is at risk of falling behind in terms of using state-of-the-art instrumentation to solve problems related to particulate behavior in the environment. The availability of nutrients in sustainable systems depends on reactions at particulate surfaces that often must be observed at the microscopic scale. The transport of toxic contaminants is governed by the movement, dissolution, and nucleation of particulate matter. Microscopic and spectroscopic methods are needed to follow such particles, determine their static and dynamic composition, and to determine their availability to living organisms. The situation may be likened to the current ability to characterize microbial communities in natural systems by the analysis of genetic material. Without the application of molecular tools, we will not have the required knowledge to advance agricultural systems to minimize inputs and contamination while optimizing production and economy. C. The technical feasibility of the research. A common thread that runs through much environmental research is the importance of processes that operate simultaneously on different spatial and temporal scales. For instance, major questions surround particulate matter affecting rural air, soil, and water quality. The technical feasibility of applying synchrotron-based methods to a wide range of sample sizes and chemical compositions is amply supported by the current scientific literature. The utilization of a combination of techniques to accomplish full characterization of particles and to relate these properties to behavior in complex systems has become increasingly important and successful. We will extend these tested approaches to agricultural systems. D. The advantages for doing the work as a multi-state effort. There are several advantages in doing this project as a multi-state effort. First, particulate matter (PM) is transported across state and regional boundaries by both air and water making it a regional rather than local problem. Second, just as urban PM emissions vary considerably from one metropolitan area to another, we can expect rural PM emissions also vary because livestock industry, crops, farming practices, soils, and water chemistry vary regionally. Third, the central focus of this project (integrated modern instrumentation, including synchrotron microspectroscopy) demands extensive cooperation among members: sharing experience with specific facilities and analytical techniques and sharing disciplinary expertise (soil, water, and air chemistry, microbiology, etc.). Fourth, this project has two implicit strategies for reaching its objectives. It will continue to promote the use of synchrotron sources to push the envelope in terms of micro-spectroscopic characterization of particles and will integrate synchrotron techniques with other state-of-art-tools provided by national labs and universities. The latter logically begins with sharing samples and data for multiple analyses but would yield optimal progress if the collaborations went deeper. In the past, synchrotron research by soil scientists primarily focused on industrial contaminants, i.e., metals and metalloids. There are many opportunities now with micro-focused techniques to study agricultural contaminants such as metals, phosphate, etc. in biosolid amended soils and biosolid materials that will link more basic soil science with applied soil science, particularly in the area of nutrient management. Finally, the members have already established an excellent record of multi-state collaboration. There is no reason this will diminish. E. What the likely impacts will be from successfully completing the work. This project will enhance our ability to assess the impact of micro- and nano-sized particles on processes taking place in agricultural and natural ecosystems by elucidating links between particulate (physical, biological and chemical) properties and their role in the sustainability and productivity of those systems. Research activities coordinated under this project will result in a catalog of physical and chemical properties of particulates related to agriculture production and of evaluations of the rate and transfer mechanisms of particulates through the environment. A greater number of scientists from state agricultural experiment stations will be utilizing the advanced analytical facilities funded by DOE and NSF to address important questions related to environmental protection and agricultural production. This will lead to the development a better understanding of the behavior of pollutant and nutrient elements and compounds associated with fine particles in soil, water and air.
Last Modified:
01-Jun-2010
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