Journal of the Marine Biological Association of the UK

Research Article

Tolerance to heavy metals in Littorina saxatilis from a metal contaminated estuary in the Isle of Man

Erema R.  Daka a1p1c1 and Stephen J.  Hawkins a2a3
a1 Port Erin Marine Laboratory, School of Biological Sciences, University of Liverpool, Port Erin, Isle of Man, IM9 6JA, UK
a2 Division of Biodiversity and Ecology, School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
a3 Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK

Article author query
daka er   [PubMed][Google Scholar] 
hawkins sj   [PubMed][Google Scholar] 


Population differences were measured in the tolerance of Littorina saxatilis from sites around the Isle of Man, to acute exposure to zinc, lead, copper and cadmium. Animals from a site influenced by disused mine run-off in Laxey estuary (high zinc) were compared with animals from less contaminated estuaries (Peel-high lead, but lower zinc), and the relatively uncontaminated Castletown and Ramsey estuaries, plus the open coast near Derbyhaven. Median lethal times (LT50) were estimated for each test concentration (5, 10, 20 mg l−1 Zn; 5, 10 mg l−1 Pb; 0·5, 1·0, 2·0 mg l−1 Cu and Cd) except for those that did not produce sufficient mortalities. Individuals from Laxey estuary showed significantly higher tolerances to zinc (10 mg l−1) and lead (5 mg l−1) than animals from the unpolluted sites. No co-tolerance to copper or cadmium was apparent. Population tolerance to zinc was correlated with reduced accumulation rates. Lead tolerance may result from the ability of the tolerant individuals to sequester the metal and detoxify it in their tissues; the littorinids from Laxey had significantly higher rates of lead accumulation.

(Received September 5 2003)
(Accepted February 9 2004)

c1 e-mail:
p1 Department of Biological Sciences, Rivers State University of Science and Technology, PMB 5080, Port Harcourt, Nigeria