Arctic versus temperate comparison of risk assessment metrics for 2-methyl-naphthalene.

Reliable risk assessment approaches for Arctic environments are requested to manage potential impacts associated with increased activities in Arctic regions. We performed toxicity tests on Arctic and temperate species exposed to the narcotic acting oil component, 2-methyl naphthalene. The experimental results were used to quantify concentration causing lethality to 50% of exposed individuals and no-effect concentration (individual level). For estimates at community level, the hazardous concentrations affecting 5% and 50% of the species were calculated from sensitivity distribution curves. These survival metrics were then used to elucidate whether temperate toxicity data used in risk assessment are sufficiently representative for the Arctic. Taking data uncertainty into consideration, we found no regional difference in tolerances to 2-methyl naphthalene either at the species level or at the community level. Hence these data support a conclusion that values of survival metrics for temperate regions are transferrable to the Arctic for the chemical 2-methyl naphthalene, as long as extrapolation techniques are properly applied and uncertainties are taken into consideration.