Effects of chronic cadmium exposures on growth of larvae of an Hawaiian bivalve, Isognomon californicum

Abstract

Young bivalve larvae (3 d old) were exposed to environmentally realistic concentrations of cadmium (2, 10, 20, and 50 pg 1 under static exposure conditions for 28 d, a peilod that spans most of thelr larval lifespan The effects on growth werc evaluated in terms of both size and weight paiameters Cd effects on size growth (length and height) were signlficantly different, but subtle, mostly characterized by a slow gradual decllne, but remaining at 2 80 % of control sizes However the effects of Cd on weight (total dry weight, shell weight, and tissue w e~g h t )were much more dramatic After only 4 d Cd-exposed larvae weighed < 80 % of the controls (total dry weight), and tissue weights were between 35 and 51 % of controls With continued exposures there was some improvement, but then growth stabilized at levels signlficantly lower than the controls or continued to decline This response of lnltial severe effects, readlustment, and restabilization represents an adaptive response medlated by homeostatic mechanisms Howe\iei, the mechanisms were unable to amellorate the toxic effects Therefore, weight was more sensitive than slze as an ind~cator of adaptive response and stress The capacity for recovery was evaluated by exposing some larvae to Cd for 14 d and allowlng them to depurate for 14 d Only larvae initially exposed to 2 u g 1-I C d showed significant recovery The effects on growth are discussed with regard to Cd t~s s u e concenl-ralions and regulatory mechanisms

Mesocosm Study ofMytilus edulisLarvae and Postlarvae, Including the Settlement Phase, Exposed to a Gradient of Tributyltin

“…No data were obtained on changes in shell dimensions for larvae and postlarvae exposed to TBT; however, Ringwood (1992) found that cadmium has no effect on shell lengthshell width relations for larvae of the bivalve Isognomon californicum. In the present study the postlarvae in 1150 ng Sn liter\ have a different shell length-shell width relation compared with postlarvae in the other TBT concentrations.…”

Variation among populations in the resistance of Mytilus edulis embryos to copper:adaptation to pollution?

“…The precise effect of this proposed genetic component to embryo copper resistance is not yet known. Although veliger larvae may be capable of producing metallothioneins in response to metal stress (Roesijadi et al 1982, Ringwood 1992, metallothionein induction in the embryo is unlikely to be possible before activation of the zygotic genome at gastrulation. Metallothionein-like proteins have, however, been found in unfertilised sea-urchin eggs (Ohtake et al 1983); the greater resistance of Westerschelde mussel embryos may be a result of inheritance of maternal metallothioneins.…”

Effect of different cadmium levels on growth and biochemical parameters of Cyprinus carpio fingerlings reared in a close system.

“…Cadmium is toxic and derives from the natural reservoirs, production activities (Foulkes, 1986;EPA, 2007), and participates in both toxicological and ecotoxicological risks (Waisberg et al, 2003 andWHO, 1992). The natural level of cadmium in fresh water is 0.1 to 10 μg/l, while in discharged water can fluctuate from 50 μg/l to 10,000,000 μg/l due to the anthropogenic processes (Singhal and Abusaria, 1990;Ringwood, 1992).…”