Abstract:
Chronic toxicity test methods for assessing the toxicity of contaminants to tropical marine organisms are generally lacking. A 96-h chronic growth rate toxicity test was developed for the larval stage of the tropical dogwhelk, Nassarius dorsatus. Growth rates of N. dorsatus larvae were assessed following exposures to copper (Cu), aluminium (Al), gallium (Ga), and molybdenum (Mo). Exposure to Cu at 28 degrees C validated the sensitivity of the test method, with 10% (EC10) and 50% (EC50) effect concentrations of 4.2g/L and 7.3g/L Cu, respectively. The EC10 and EC50 values for Al (<0.45-m filtered fraction) at 28 degrees C were 115g/L and 185g/L, respectively. The toxicity of Cu and Al was also assessed at 24 degrees C and 31 degrees C, representing average year-round water temperatures for subtropical and tropical Australian coastal environments. At 24 degrees C, the growth rate of control larvae was reduced by 52% compared with the growth rate at 28 degrees C and there was an increase in sensitivity to Cu (EC50=4.7g/L) but a similar sensitivity to Al (EC50=180g/L). At 31 degrees C the control growth rate increased by 35% from that measured at 28 degrees C and there was reduced sensitivity to both Cu and Al (EC50s=8.5g/L and 642g/L, respectively). There was minimal toxicity resulting from Ga (EC50=4560g/L) and Mo (no effect at 7000g/L Mo). Environ Toxicol Chem 2016;35:1788-1795. (c) 2015 SETAC
