The uptake and accumulation of zinc by the shore crab Carcinus maenas
have been studied in different dissolved Zn concentrations. Carcinus m
aenas accumulated about 2, 10 and 200% of its initial load of Zn on ex
posure to 23, 100 and 3162 mu g l(-1) radioactively labelled Zn respec
tively for 21 days. No significant Zn excretion was observed in crabs
exposed to 100 mu g Zn l(-1) suggesting that C. maenas normally mainta
ins a relatively unchanged body Zn content by maintaining a low Zn upt
ake rate, rather than a high Zn turnover rate. Zn excretion did occur
when crabs were exposed to the environmentally high concentration of 3
162 mu g Zn l(-1). The exoskeleton was found to be an important storag
e site for Zn absorbed from solution.