Abstract
Incorporated crumb rubber (CR) increased Zn tissue levels up to nine times the normal range in tree species. There was a linear increase in Zn tissue accumulation with increasing percentages of crumb rubber for river birch (Betula nigra L.), lacebark elm (Ulmus parvifolia Jacq.), and pecan [Carya illinoinensis (Wangenh.) C. Koch]. Pecan leaves containing high levels of Zn exhibited no visual symptoms, unlike the remaining tree species exhibiting leaf chlorosis. Results suggest that crumb rubber incorporated at rates greater than 25% may cause abnormally high concentrations of Zn to accumulate in plant tissue.
ACKNOWLEDGMENTS
The authors extend gratitude to David Wall and Gary Ramsey of the Louisiana Department of Agricultural Chemistry for their assistance in elemental analysis.