TA4 Metals in the Environment: Dietary Concerns in Aquatic Systems
Room 16A/B, Level 4
8:00 AM - 12:00 PM, Tuesday, 11 November 2003
Chair: Adams, Bill ,
Co-chair: Meyer, Joe ,
(191) Comparison of Sediment and Detritus Toxicity from a Heavy Metal Contaminated Freshwater Marsh.
Bentivegna, C1, Bugel, S1, Alfano, J, Czechowicz, K1, 1 Seton Hall University, South Orange, New Jersey, USA
ABSTRACT- Wetlands are now being recognized as valuable ecosystems and efforts are underway in many areas to revitalize and/or restore them. Strategies for improvement require a better understanding of the interactions between their biota and abiotic features. A comprehensive study of Kearny marsh was undertaken to evaluate its current environmental health. Kearny marsh is a 370 acre, freshwater wetland located in the Hackensack Meadowlands, NJ, USA. It is highly anaerobic and surrounded by landfills and busy highways. This paper reports on toxicity tests of whole sediment and detritus from 6 sites around the marsh. Detritus was prepared by washing whole sediment through a 1 mm sieve using on site water. Test sediments and detritus were collected in June and October. The test organism was a laboratory population of Chironomus riparius. Second instars were exposed to whole sediment or detritus and were either fed ground fish food or unfed. Growth (mg/larvae) at 10 d was the endpoint. Results showed no statistical differences in growth of fed larvae exposed to sediments and detritus from June and October collections. Unfed larvae showed no statistical differences in June sediments, but growth was significantly suppressed in some October sediments. For detritus, growth in unfed larvae was suppressed at some sites in June and October. There was considerable difference between growth of fed and unfed larvae. Fed larvae increased about 10x compared to initial weights while unfed increased 3.5X. This indicated that neither the sediment nor the detritus had much nutritional value. There was no significant difference in growth between sediment and detritus from a particular site, which indicated that toxicity was primarily due to detritus. Comparison of total organic carbon sediment content and growth gave a significant inverse relationship (R2 = 0.80) supporting the toxic contribution of detritus in this ecosystem.
Key words: sediment, wetland, chironomid, heavy metals