Superfund Research Program
Variation in Bioaccumulation and Biomagnification of Metals in Lakes throughout the Northeastern Region of the U.S.A.
Project Leader: Carol L. Folt
Grant Number: P42ES007373
Funding Period: 1995 - 2000
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Progress Reports
Year: 1999 1998 1997 1996 1995
In the past year construction of a trace metal clean room has been completed and new methods have been developed for field sampling and lab analyses allowing ultra-clean procedures for detecting metals in individual animals. Samples were taken from 20 lakes in New England to measure metal levels (mercury, cadmium, lead, and arsenic) in water, particulate, sediment, and planktonic samples and to characterize physical and chemical variables that affect metal chemistry in lakes. Samples were analyzed for metals (mercury, cadmium, lead, and arsenic) and other non-metallic parameters (biomass, chlorophyll, taxonomy, and dissolved oxygen content (DOC)). Biochemical indicators of metal stress in zooplankton were investigated in order to explore their use as field biomarkers. Experimental protocols are being developed for measuring HSP 27 induction in zooplankton exposed to arsenic and metallothionein induction in animals exposed to cadmium. Both biomarker studies use gel electrophoresis and PCR techniques with laboratory cultures of the cladoceran Daphnia pulex. The ultimate goals of the study are to establish baseline data on levels of potentially toxic essential and non-essential metals in organisms throughout the food webs of natural lake ecosystems, and to compare and contrast metal levels in organisms from lakes which vary with respect to food web complexity, proximity to urban centers or Superfund sites, and thermal regimes. These factors can alter the processes of bioaccumulation and biomagnification, affect the diversity and structure of aquatic food webs, and ultimately influence the potential for human exposure to metals via ingestion of fish.