Marine Biology
June 1996, Volume 125, Issue 4, pp 701-706
Temperature effects on accumulation and retention of radionuclides in the sea star, Asterias forbesi: implications for contaminated northern waters
D. A. Hutchins,
I. Stupakoff,
N. S. Fisher
Abstract
Radioactive waste disposal and nuclear testing concentrated in high latitudes in the northern hemisphere have resulted in the accumulation of radionuclides in Arctic marine ecosystems, but little is known of the consequences for marine biota in these waters. Under controlled laboratory conditions in May through September 1994, we examined the bioaccumulation in sea stars, Asterias forbesi (Desor), or the radionuclides 241Am, 57Co and 137Cs, all of which are important components of disposed radioactive wastes. Experiments at 2 and 12?C determined the relative importance of food (the bivalve, Macoma balthica) and water as sources of radionuclides and assessed the influence of temperature on radionuclide influx and efflux rates.
The lower temperature greatly increased the retention of radionuclides ingested with food; for instance, the biological half-life (tb 1/2) of 241Am in the sea stars was 31 d at 12?C, but was virtually infinite at 2?C. Retention of ingested 57Co was also increased at 2?C (tb 1/2=41 d). 137Cs was not accumulated from food. Low temperature significantly reduced net influx rates of 137Cs from water, but did not affect net uptake of 241Am or 57Co. Temperature had little effect on the retention of all three isotopes obtained from the dissolved phase.
These experiments suggest that extrapolation of results of previous radioecological studies, conducted at warmer temperatures, to polar or temperate winter environments may be problematic, and that nuclear waste isotopes obtained through trophic transfer may be retained far more efficiently in high latitude marine biota than by fauna from warmer ecosystems.
Communicated by J. P. Grassle, New Brunswick
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