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Title: Heavy metal tolerance and metallothionein induction in fathead minnows: results from field and laboratory investigations

Thesis/Dissertation ·
OSTI ID:6238268

Toxicity tests were conducted to quantify the metal tolerance of two natural populations of fathead minnows (Pimephales promelas). One group of organisms was taken from a metal-contaminated flyash pond and the other population was collected from Newtown hatchery ponds. As determined in acute toxicity tests, ash pond minnows were significantly more tolerant to cadmium and copper than were hatchery minnows. Both populations were about equally tolerant to zinc. After ash pond minnows were transferred to reconstituted water in the laboratory, tolerance to cadmium and copper decreased signficantly after 7 days. Conversely, tolerance was increased in hatchery minnows following acclimation in the laboratory to sublethal concentrations of cadmium. This induced tolerance in cadmium-acclimated hatchery minnows was lost when organisms were transferred to control water for 7 days. The results support the conclusion that fathead minnows develop increased tolerance to cadmium and copper following prolonged sublethal exposure to these metals, and that this metal-induced tolerance is not sustained once organisms are removed from toxicant stress. As determined in correlated biochemical studies, gill metallothionein concentrations correlated closely with the variations in tolerance exhibited during cadmium acclimation and deacclimation. Therefore, tolerance induction was attributed to increased production of metallothionein, a protein which selectively binds and sequesters cadmium, copper and certian other metals.

OSTI ID:
6238268
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English