THE SPATIAL DISTRIBUTION OF TRAFFIC DERIVED POLLUTANTS IN SEVERAL TYPES OF STORMWATER RETENTION STRUCTURES IN URBAN AREAS NEAR BINGHAMTON, NY

Roadway and parking lot runoff are substantial contributors of pollution to urban ecosystems. To better quantify the impact and geochemical complexity of these pollutant sources, it is important to understand how pollutants are transported to and through stormwater retention structures.

24 soil cores from a freeway median capturing near-roadway deposition (NRD), 15 cores from a retention wetland capturing parking lot runoff (PLR), and 30 cores from a hybrid wetland with combined PLR and NRD inputs were collected. The 69 cores were sectioned by depth, microwave digested in nitric acid, and analyzed using ICP-OES and ICP-MS techniques, followed by geospatial analysis of the distribution of the concentrations for 23 elements at the three sites.

The accumulation of traffic derived pollutants is indicated by near-roadway concentrations of Ca, Cd, Cu, Mo, Sr, and Zn that are elevated up to 3x’s above background levels at the freeway site, and in their inverse relationship in concentration vs distance from the roadway. Concentrations of some elements in the PLR retention wetland sediment are even further elevated (Ca – 5x’s, As, Cu, and Zn – 2x’s). From a spatial context, the PLR retention wetland has elevated concentrations of As, Cr, Cu, Sb, and Zn near the inlet and the outlet, with lower concentrations of these elements near the wetland center. These patterns could indicate preferential transport of metals based on particle size.

The hybrid site has characteristics of both PLR and NRD impacts. At the hybrid site, only Ca and Sr show the inverse relationship in concentration vs distance from the roadway, but Cr, Cu, Sb, and Zn concentrations maintain the pattern of being elevated at the inlet and outlet that was noted in the PLR retention wetland. This might indicate particle size dependent preferential metal transport from the roadway to the wetland due to roadway embankment characteristics.

Because of the proximity of these stormwater retention structures to the Susquehanna River, and the river’s role as a municipal water source, it is imperative to better understand the transport and storage of pollutants that have the potential to impact human health. Therefore, further studies are underway to understand the solid and dissolved phase partitioning of contaminants during storm events in stormwater retention structures.