Causeway and bridge design to reduce roadway contaminant runoff to a saltmarsh ecosystem
- Univ. of Charleston, SC (United States)
- Citadel Coll., Charleston, SC (United States)
At the insistence of the local fishermen and landowners the Isle of Palms connector (Charleston, South Carolina) was built with a unique set of environmental safeguards so that the saltmarsh beneath the bridge would remain uncontaminated. This study evaluates the effectiveness of the bridge, in order to judge the suitability of the design for other areas. A two kilometer causeway over the marsh has catch pans to hold runoff, except that a heavy rain causes the pans to overflow. A one kilometer span over the Intracoastal waterway has pipes that redirect the runoff into gravel lined spoils. The bridge was monitored quarterly from January to December 1994. Extensive testing was performed during October 1994 to compare sites around the bridge and within the watershed to a pristine site and a to highly contaminated site. Sediment and water samples were tested with the Microtox{reg_sign} bioluminescence assay and a Latuca sativa (lettuce) seed germination and growth assay. Sediment samples were also tested with a Mercenaria mercenaria (littleneck clam) growth bioassay. Benthic community structure was analyzed for sites around the bridge. While very few statistically significant instances of toxicity were found, there are some trends that make it apparent that the bridge runoff may have some effects. There is no apparent accumulation of toxic contaminants from the pan overflow in sediments beneath the bridge, and this bridge design should ameliorate the effects of bridge runoff in almost any area. Future research using chemical analysis of the fate and transport of contaminants within the bridge and the surrounding area is suggested.
- OSTI ID:
- 390148
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9646%%433
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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