Temporal trends of organochlorines and mercury in seabird eggs from the Canadian Arctic, 1975-2003

Organochlorine pesticides, PCBs, total mercury and selenium were measured in eggs of thick-billed murres, northern fulmars and black-legged kittiwakes collected from Prince Leopold Island in the Canadian High Arctic between 1975 and 2003. The primary organochlorines found were SigmaPCB, p,p'-DDE, oxychlordane, and hexachlorobenzene (HCB). Most of organochlorines analyzed showed either significant declines or no significant change between 1975 and 2003 in all three species. However, significant increases were observed for SigmaHCH in the kittiwakes and fulmars, and beta-HCH in the murres and fulmars. Mercury increased significantly in eggs of murres and fulmars, whereas mercury in the kittiwakes did not change significantly over the study period. Statistical analyses included stable-nitrogen isotope ratios (delta(15)N) to control for any variation in trophic level over time. Although the contaminant concentrations reported in this study are below published threshold values, mercury and beta-HCH concentrations continue to increase suggesting that continued monitoring is warranted.     

Removal of hexafluoroarsenate from waters

Arsenic predominantly occurs in natural ground and surface waters as arsenate and arsenite. Other arsenic species can also be present in anthropogenically influenced waters. By means of a newly-developed speciation technique an arsenic compound was identified as hexafluoroarsenate at high concentration (about 0.8mgl(-1) as As) in a lake polluted by waste water from a former crystal glass factory. This compound shows a completely different behavior than common arsenite and arsenate in waters. However, respective literature data were little found regarding its environmental behavior as well as the applicable remediation technologies. Conventional arsenic treatment mechanisms, such as the well-known sorption to iron hydroxides, can not be used to remediate water with this compound. Hence, an effective method to remove hexafluoroarsenate from water was developed using its strong affinity to anion exchangers (strong basic exchangers with quaternary ammonium groups). The sorption can be described by a Langmuir isotherm and first-order kinetics with a half-life of about 10min. Interferences by sulphate and fluoride, present at much higher concentrations in the polluted lake water, might be expected due to the anion exchange mechanism, but were shown to be of minor importance.     

Climate change stimulates the growth of the intertidal macroalgae <Emphasis Type="Italic">Ascophyllum nodosum</Emphasis> near the northern distribution limit

Ascophyllum nodosum is a foundation macroalgae of the intertidal zone that distributes across latitude 41.3–69.7°N. We tested the hypothesis that growth of A. nodosum near the northern distribution edge increases with warming. We retrospectively quantified the growth of eight A. nodosum populations at West Greenland and North Norway (from 64°N to 69°N). For seven populations, we measured growth rates since 1997–2002 and for one of them we extended the time series back to 1956 using published estimates. Individuals at northern populations elongated between 2.0 and 9.1 cm year^?1 and this variability correlated with temperature and annual ice-free days. A spatial comparison of A. nodosum growth across the species distribution range showed that Northern (and coldest) populations grew at the slowest rates. Our results demonstrate that arctic climate change enhances the growth of A. nodosum populations and suggest that their productivity may increase in response to projected global warming.