Groundwater Effects from Highway Tire Shred Use

Abstract

Approximately 250,000 shredded tires have been used to construct a highway exit ramp as part of a demonstration project. One upgradient well was installed before the tire shreds were put in place. Two downgradient wells and two tire fill sampling ports were installed during the project. Levels of organic compounds and metals have been monitored since the project was completed in May of 2001 . Organic compounds were not detected in the leachate or downgradient groundwater in significant amounts. Arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), selenium (Se), silver (Ag), and zinc (Zn) were quantified in both filtered and unfiltered samples. Of most concern is the source of elevated levels of Ba, Cd, Fe, Mn, and Zn in filtered samples when compared with water quality standards. Zn, Cd, and Ba are elevated in one of the tire fill ports, whereas Fe and Mn have been consistently elevated in the downgradient wells. The elevated Zn, Cd, and Ba may be related to the use of shredded tires. The elevated Fe and Mn may be associated with traffic on the adjacent interstate and ramp and the hydrogeology of the site. The concentrations of iron and manganese in the downgradient groundwater would be a public health concern if the water were used for human consumption. It is important to evaluate the combined long-term effects of tire shreds and runoff from roadways on groundwater quality where tire shreds are used in highway construction.

Keywords:

• tire shreds
• highway
• manganese
• organics
• groundwater

Notes

* Reference elevation = top of PVC well casing.