(Table 1) Retinol (vitamin A) and alpha-tocopherol (vitamin E) concentration in polar bear (Ursus maritimus) kidney

Vitamins A and E content of inner organs, among these the kidneys, are increasingly being used as an indicator of adverse effects caused to the organism by e.g. environmental contaminants. In general, only a renal sub sample is used for analyses, and it is thus essential to know which part of the organ to sample in order to get a representative value for this important biomarker. The aim here was to assess the distribution of vitamins A (retinol) and E (alpha-tocopherol) within the polar bear multireniculate kidney (i.e. polar vs. medial position) and also within the cortex vs. medulla of each separate renculi. The results showed no significant difference between the medial and polar renculi with regards to either retinol (p = 0.44) or alpha-tocopherol (p = 0.75). There were, however, significant differences between cortex and medulla for both vitamins (retinol, p = 0.0003; alpha-tocopherol, p<0.0001). The kidney cortex contained higher values of both vitamins than the medulla; on average 29% more retinol and 57% more alpha-tocopherol. Mean concentrations in the medulla was 2.7 mg/kg for retinol and 116 mg/kg for alpha-tocopherol, and in the cortex 3.5 mg/kg for retinol and 182 mg/kg for alpha-tocopherol. These results clearly indicate that one should take precautions when analyzing retinol and alpha-tocopherol in polar bear kidneys. Prior to analysis, the renculi should be separated into medulla and cortex. The results indicated no significant differences between renculi from different parts of the kidney.

alpha- and gamma-Hexachlorocyclohexane concentrations in brine, bulk sea-ice, water and air during a CCGS Amundsen cruise to the Canadian western Arctic

We used holes augered partially into first-year sea ice (sumps) to determine a- and g-HCH concentrations in sea-ice brine. The overwintering of the CCGS Amundsen in the Canadian western Arctic, as part of the Circumpolar Flaw Lead (CFL) System Study, provided the circumstances to allow brine to accumulate in sumps sufficiently to test the methodology. We show, for the first time, that as much as 50% of total HCHs in seawater can become entrapped within the ice crystal matrix. On average, in the winter first-year sea ice HCH brine concentrations reached 4.013 ± 0.307 ng/L and 0.423 ± 0.013 ng/L for the a- and g-isomer, respectively. In the spring, HCHs decreased gradually with time, with increasing brine volume fraction and decreasing brine salinity. These decreasing concentrations could be accounted for by both the dilution with the ice crystal matrix and under-ice seawater. We propose that the former process plays a more significant role considering brine volume fractions calculated in this study were below 20%. Levels of HCHs in the brine exceed under-ice water concentrations by approximately a factor of 3, a circumstance suggesting that the brine ecosystem has been, and continues to be, the most exposed to HCHs.

Physical properties and alpha-/gamma-HCH concentrations in sea-ice and snow samples obtained during a CCGS Amundsen cruise, eastern Beaufort Sea

The alpha- and gamma-hexachlorocyclohexanes (HCHs) are being scavenged from the atmosphere by falling snow, with the average total scavenging ratios (WT) of 3.8 x 10**4 and 9.6 x 10**3, respectively. After deposition, HCH snow concentrations can decrease by 40% because of snowpack ventilation and increase by 50% because of upward migration of brine from the ice. HCH vertical distribution in sufficiently cold winter sea ice, which maintains brine volume fractions <5%, reflects the ice growth history. Initially, the entrapment of brine (and HCHs) in ice depends on the rates of ice growth and desalination. However, after approximately the first week of ice formation, ice growth rate becomes dominant. Deviations of HCH concentrations from the values predicted by the ice bulk salinity (rate of brine entrapment) can be explained by spatial variability of HCHs in surface water. HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring when snow meltwater percolates into the ice, delivering HCHs to the upper ocean via desalination by flushing. Percolation can lead to an increase in alpha- and gamma-HCH in the sea ice by up to 2%-18% and 4%-32%, respectively.

(Table 1) Annual mean concentrations of atmospheric a- and g-Hexachlorocyclohexane at stations Alert, Canada and Zeppelin, Norway

Twelve year datasets of weekly atmospheric concentrations of alpha- and gamma-HCH were compared between the two Arctic monitoring stations of Alert, Nunavut, Canada, and Zeppelin Mountain, Svalbard, Norway. Time-series analysis was conducted with the use of dynamic harmonic regression (DHR), which provided a very good model fit, to examine both the seasonal behaviour in these isomers and the longer-term, underlying trends. Strong spatial differences were not apparent between the two sites, although subtle differences in seasonal behaviour and composition were identified. For example, the composition of gamma-HCH to total HCH (alpha + gamma) was greater at Zeppelin compared to Alert, probably reflecting this site's proximity to major use regions of lindane. Pronounced seasonality in air concentrations for gamma-HCH was marked by a 'spring maximum event' (SME), confirming earlier studies. For alpha-HCH, the SME was much weaker and only evident at Alert, whereas at Zeppelin, seasonal fluctuations for alpha-HCH were marked by elevated concentrations in summer and lower concentrations during winter, with this pattern most apparent for the years after 2000. We attribute this difference in spatial and temporal patterns to the Arctic oscillation. A similar climatic pattern was not evident at either site in the gamma-HCH data. Seasonally adjusted, long-term trends revealed declining concentrations at both sites for alpha- and gamma-HCH over the entire time-series. Recent legislation affecting lindane use appear to account for this decline in gamma-HCH, with little evidence of a delay or 'lag' between the banning of lindane in Europe (a main source region) or Canada, and a decline in air concentrations observed at both Arctic sites.