Metal toxicity in a sediment-dwelling polychaete: threshold body concentrations or overwhelming accumulation rates?
We followed the net accumulation of As, Cu and Zn in the deposit-feeding polychaete Arenicola marina exposed in the laboratory to natural metal-contaminated sediments, one exposure leading to mass mortality between day 10 and 20, and the other not causing lethality over a period of 60 days of exposure. The worms showed lower total accumulated metal concentrations just before mortality occurred (<20 days) at the lethal exposure, than after 30 days of exposure to sediments not causing mortality. Moreover rates of accumulation of As, Cu and Zn were significantly higher in the lethal exposure than in the sublethal exposure. Our results show that it is not possible to link mortality to a critical total body concentration, and we add to a growing body of literature indicating that metal toxicity occurs when organisms cannot cope with overwhelming influx and subsequent accumulation rates.
Carmen Casado-Martinez
M
M
Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom. c.casado-martinez@nhm.ac.uk
Smith
Brian D
BD
Luoma
Samuel N
SN
Rainbow
Philip S
PS
D000818:Animals; D001151:Arsenic / Q000378:metabolism / Q000633:toxicity*; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D019015:Geologic Sediments / Q000737:chemistry; D011077:Polychaeta / Q000187:drug effects* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*; D015032:Zinc / Q000378:metabolism / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D003300:Copper; D015032:Zinc; D001151:Arsenic