DetectionTrees as contamination detectors
Determining the presence and concentration of contaminants has been an invasive, laborious process; now a Missouri University of Science and Technology team has developed a faster, more economical method of determining such contamination at miniscule levels; the Army has funded additional research for explosive residue detection
Determining the presence of groundwater or soil contaminants is an ongoing and painstaking process. Ever-present questions of whether industrial activity in an area has left behind harmful pollutants have been answerable only with extensive soil and groundwater sampling.
All that may now be past.
Researchers at Missouri Univ. of Science and Technology have developed a method to detect the presence of contamination without shovels or vials of groundwater. They are using trees.
Laboratoryequipment.com reports that the technique, known as phytoforensics, uses the natural processes in trees to determine the presence of contaminants.
According to Dr. Joel Burken, professor of civil and environmental engineering at the university, the process is much less expensive, time-consuming and intrusive than traditional techniques. “The process of core-sampling plants has been around for a while,” Burken says, “but we’re taking a new approach that will improve the process on multiple levels. Sampling is easy, fast and inexpensive for quickly identifying polluted areas or contamination patterns.”
The sampling Burken is referring to is radically different from sampling techniques of past years. Then, the samples were vials of soil and water from the area, and core extractions from the tree trunk.
Burken’s technique, however, requires no such extensive sampling. Rather, it uses a thin filament known as a solid-phase microextraction fiber, or SPME, capable of detecting even trace amounts compounds at the parts per trillion or even quadrillion level. A core hole is drilled into the trunk, and the SPME is inserted to collect the required sample.
As trees grow, their root systems collect water and nutrients from the subsurface. Collected compounds would include any contaminants present in the area, and the degree of presence would be an indicator of level of contamination. All these compounds are collected on the pencil-lead-thick filament, then transported to a laboratory for analysis.
During the testing of the method, the Missouri S&T research team found that solvents used in a former dry-cleaning business nearby had seeped into the groundwater in a park, though not in concentrations that were a hazard to human health.
Recently, the Army’s Leonard Wood Institute provided funding to a Missouri S&T team of Dr. Burken, Dr. Yinfa Ma, Curators’ Teaching Professor of chemistry, and Dr. Honglan Shi, assistant research professor of chemistry to adapt the method to detect trace amounts of explosives. There are also plans to adapt the technique to detect the presence of pesticides and herbicides.
