USING A TRIAD APPROACH IN ASSESSING HAZARDOUS WASTE SITE
LEACHING FROM A SUPERFUND SITE INTO THE WOLF RIVER, A
MISSISSIPPI RIVER TRIBUTARY.

Christy J. Leppanen1, Pat M. Blanner1, Roger S. Allan1, William H. Benson2
and Kurt J. Maier1
1Department of Biology, The University of Memphis, Memphis, TN 38152 
2Department of Pharmacology, University of Mississippi, University, MS 38677

A triad approach was employed in the evaluation of sediment toxicity in the Wolf
River, a Mississippi River tributary, adjacent to the North Hollywood Dump, a
federally listed superfund site. Chemical analyses were done for 18
organochlorine pesticides, 21 PCB congeners and 10 metals. Sediment toxicity
was evaluated using the freshwater invertebrate, Chironomus tentans and
Hyallela azteca. Benthic macroinvertebrate diversity and abundance was
assessed with a family-level biotic index. Mean Al, Ba, Cd, Cu, Fe, Ni, Pb and
Zn concentrations were significantly higher in samples collected in the spring
compared to the fall. Both spring and fall sediments exhibited toxicity
downstream from, adjacent to, and upstream from the dump. Toxicity was
significantly higher in the fall sediment samples, however, a consistent trend was
not observed. Toxicity was typically greater in the fall and metal concentrations
typically higher in the spring suggesting that metals were not responsible for the
observed toxicity. Sediment associated organochlorine pesticide and PCB
congener concentrations were all below detectable limits, indicating that there
potential contaminants are not contributing to the observed toxicity. No
differences were found in benthic macroinvertebrate community structure, which
was composed of predominantly pollution-tolerant families, among seasons or
river reaches. The communities appear to be limited by the physical
characteristics of the river [substrate instability, low TOC (<0.6%), flow].
Sediments in the urban reaches of the Wolf River appear to be degraded; the
dump can not be isolated as a source of sediment contamination or toxicity in this
study.

Keywords:  triad assessment, sediment toxicity, hazardous waste site, Wolf
River, macroinvertebrate communities


Correspondence to:

Kurt J. Maier
Department of Biology
The University of Memphis
Memphis, TN     38152
T: (901) 678-2327
F: (901) 678-4746
E: kjmaier@cc.memphis.edu

I prefer a platform session