Persistent organic pollutants and mercury in marine biota of the Canadian Arctic: An overview of spatial and temporal trends

The toxicology of climate change: Environmental contaminants in a warming world

“…POPs are unique in that they can move thousands of miles from their point of release and are often observed at higher latitudes. This observation is explained by the concept of global fractionation (Braune et al, 2005;Breivik et al, 2004;Wania and Mackay, 1996). Most POPs are semi-volatile enough to evaporate at temperate or tropical latitudes, existing as gases or adsorbed to aerosols in the atmosphere.…”

“…▪ Pollutant-exposed ectotherms and species at the edge of their physiological tolerance range may be especially sensitive to temperature increases. Altered environmental salinity ▪ ↓ solubility and ↑ bioavailability of pesticides/POPs ("salting out effect") ( Fortin et al, 2008;Heugens et al, 2001;Moore et al, 2003;Schiedek et al, 2007;Schlenk and El-Alfy, 1998;Schwarzenbach et al, 2003;Song and Brown, 1998;Tachikawa and Sawamura, 1994;Wang et al, 2001;Waring and Moore, 2004) ▪ ↑ salinity + ↑ POP/pesticide exposure may alter osmoregulation due to altered enzymatic pathways Altered ecosystems ▪ Altered POP sequestration and/or remobilization through shifts in food sources and starvation events (AMAP, 2004;Braune et al, 2005;Furnell and Schweinsburg, 1984;Jenssen, 2006;Macdonald et al, 2005Macdonald et al, , 2003Olafsdottir et al, 1998;Ramsay and Stirling, 1982;Schiedek et al, 2007, Stirling et al, 1999) ▪ Shifts in disease vector range and severity coupled with toxicant exposure inhibiting immune response may leave wildlife more susceptible to disease ▪ Low level exposures may impair organism acclimation to ecosystem alterations induced by climate change ▪ Climate change induced changes in trophic food webs may alter POP bioaccumulation and biomagnification mykiss) exposed to the insecticide endosulfan as temperature was increased from 13°C to 16°C. In contrast to these findings, pyrethroids and DDT are generally thought to be more toxic under low temperature conditions, which may be due to a sodium channel modulated increase in nervous system vulnerability at lower temperatures (Narahashi, 2000).…”

“…Important solvent switching and solvent depletion processes involve the partitioning of POPs from water to phytoplankton and zooplankton at the base of aquatic food chains followed by bioaccumulation and biomagnification up the food chain (Braune et al, 2005;Macdonald et al, 2005). Apex predators at the top of some food webs may experience significant biomagnification of POPs as a result of these solvent switching and solvent depletion processes.…”

“…Apex predators at the top of some food webs may experience significant biomagnification of POPs as a result of these solvent switching and solvent depletion processes. For example, polar bears (Ursus maritimus) generally have the highest concentrations of POPs of any Arctic animal (Braune et al, 2005). Stirling et al (1999) observe that the loss of stable ice flows linked to climate warming are the major factor contributing to Hudson Bay polar bears coming ashore for several months of fasting in progressively poorer condition.…”

“…Climate change may also alter patterns of POP bioaccumulation and biomagnification by altering bottom-up or top-down mechanisms controlling trophic food webs (Braune et al, 2005;Macdonald et al, 2003;Schiedek et al, 2007). Climate change-induced alterations in bottom-up controlling mechanisms, such as altered nutrient and primary production, may lead to the addition or removal of trophic levels .…”