GSE hosted faculty and high school students from Lockport Township High School involved with the ESRP Program at APS. Their experiment “Comparative Chemical Analysis of Soil Contamination Using Hyperaccumulators” was run at 13 IDE with GSE beamline scientists Tony Lanzirotti and Matt Newville as hosts. The experimental plan is to utilize the 13-ID-E microprobe to measure accumulated Cu abundances in leaves, stems and root sections of BRASSICA JUNCEA and SPINACH plants grown by the students in growth media containing treated lumber (containing micronized copper) and cedar wood. The plan is to measure accumulated Cu abundances in plant tissue only (leaves, stems and root sections). This experiment will determine the copper uptake by plants/vegetables grown in a container made from treated lumber. This will ultimately also determine whether or not treated lumber is considered safe in contrast to cedar wood. Additionally, the researchers will determine what parts of the plant accumulate the heavy metals. Faculty member : Mr. WIlliam Kane.
Experimental Abstract
The most popular type of lumber to use for the common gardener is treated lumber because it is cheaper, more weather resistant, insect resistant, and long-lasting compared to untreated lumber. In the past, weather-resistant lumber was pressure treated with chromated copper arsenate (CCA); however, it was realized that the chromium and arsenic from the treating process could seep into the soil over time and pose risk of toxicity to the environment and to humans. As a result, in 2003, the EPA made an agreement with preservative manufacturers to stop the production of CCA-treated wood. Because of this regulation, the preservative manufacturers started using other copper-bearing compounds to treat lumber, compounds such as alkaline copper quaternary (ACQ), copper azole (CBA), Copper- HDO (Bis-(Ncyclohexyldiazeniumdioxy- copper)), and Copper Napthenate. Even though these copper species are considered less toxic than CCA, they may still pose health risks. It is thought that exposure at high concentrations can induce abdominal pain, hematemesis, melena, jaundice, anorexia, severe thirst, diarrhea, vomiting, altered mentation, headache, coma, tachycardia, depression, fatigue, irritability, excitation, and difficulty focusing. At what exposure levels this is of concern is unclear. Although the amount of copper released by the treated wood to soil is likely low, some edible plants have the potential to hyperaccumulate Cu. Whether Cu can be accumulated to levels that may pose health risks is unknown.
We hypothesize that the use of treated lumber used as a material for a plant growing box will contaminate the soil which may be uptaken by plants such as hyperaccumulators. In order to test the effect that treated lumber has on metal concentrations in soil, we will grow two plant species known to hyperaccumulate Cu (BRASSICA JUNCEA and SPINACH) in two garden boxes: one made of treated lumber and one made of cedar wood. We will utilize beamline 13 to measure accumulated Cu abundances in leaves, stems and root sections by microfocused X-Ray fluorescence at beamline 13-ID-E and compare the effects of two types of wood. Specifically, we expect to find traces of copper or other metals within these hyperaccumulators. Using our experimental data, we can determine whether the use of treated lumber will result in an increased concentration of copper in the plants and whether these concentrations are enough to cause harm to humans. As a result, we will be able to assess whether or not the new formulas of chemicals used to treat pressure-treated lumber can cause harm to humans and the environment.
