Contaminants

Recovery of peregrine falcons in Canada

Graphic thumbnail: recovery of peregrine falcons in Canada

This bar graph shows the increase in the number of sites occupied by peregrine falcons in Canada from 1970 to 2005. The number of sites occupied was as follows: 94 in 1970; 123 in 1975; 180 in 1980; 224 in 1985; 400 in 1990; 443 in 1995; 523 in 2000; and 662 in 2005.

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Contaminant trends

Graphic thumbnail: contaminant trends

This graphic shows contaminant levels in several wild species at locations throughout Canada, over a range of time periods. The locations of the eight charts included in this graphic are shown on a map of Canada. Each chart consists of a set of line graphs of contaminants levels for individual species at one location, with the contaminant types and the years plotted depending upon what data were available. The units for all the contaminants in all charts are parts per million, abbreviated as ppm. The data points are plotted and joined with lines – there are no statistical trend lines included. Overall, the charts show mainly decreasing trends of PCBs and DDE or DDTs, varying trends in mercury levels, and overall increases in PBDEs. The increasing trends of PBDEs generally stopped or were reversed in recent years. Unless otherwise indicated in the descriptions below, the two years for which values are presented are the first and the most recent years of sampling.

Each graph is described in the following set of points, by location:

  1. This chart shows contaminants in eggs of thick-billed murres from Prince Leopold Island in the Arctic. PCBs decreased (with values of 2.4 ppm in 1975 and 0.97 ppm in 2008). Total DDTs decreased (2.0 ppm in 1975 and 1.2 ppm in 2008). Mercury levels increased (0.6 ppm in 1975 and 1.5 ppm in 2009). PBDEs showed an overall increase followed by a recent decline, rising from very low levels of 0.0044 ppm in 1975 and peaking at 0.046 ppm in 2006, then decreasing to 0.015 ppm in 2008.
  2. This chart shows contaminants in beluga blubber from the vicinity of Pangnirtung in the Arctic Archipelago. PCBs decreased (4.1 ppm in 1982 and 2.7 ppm in 2008). Total DDTs in decreased (5.1 ppm in 1982 and 1.3 ppm in 2008). PBDEs increased (0.004 ppm in 1982 and 0.021 in 2008, with levels fluctuating but not increasing since about 2000). Mercury data were not available.
  3. This chart shows contaminants in eggs of double-crested cormorants from the St. Lawrence Estuary. PCBs decreased (16 ppm in 1972 and 3.1 ppm in 2004). DDE levels decreased (5.6 ppm in 1972 and 0.55 ppm in 2004). Mercury and PBDE data were not available.
  4. This chart shows contaminants in eggs of double-crested cormorants from the Bay of Fundy. PCBs decreased (19 ppm in 1972 and 1.3 ppm in 2004). DDE levels decreased (6.6 ppm in 1972 and 0.31 ppm in 2004). Mercury and PBDE data were not available.
  5. This chart shows contaminants in lake trout from Lake Ontario. PCBs decreased (6.3 ppm in 1982 and 1.2 ppm in 2002). Total DDT levels also decreased over the same time period (1.9 ppm in 1982 and 0.63 ppm in 2002). The levels of PBDEs increased (0.27 ppm in 1979, rising to 3.3 ppm in 1993) and then began to decrease, with the most recent measurement being 1.7 ppm in 2004). Mercury data were not available.
  6. This chart shows contaminants in eggs of herring gulls from Lake Ontario. PCBs decreased more than an order of magnitude (9.5 ppm in 1981 and 0.41 ppm in 2005), as did DDE (23 ppm in 1974 and 1.6 ppm in 2007). Mercury levels decreased (0.46 ppm in 1974 and 0.30 ppm in 2007). PBDEs increased, with the trend leveling off in recent years (0.009 ppm in 1981 and 0.41 ppm in 2005).
  7. This chart shows contaminants in eggs of double-crested cormorants in the Strait of Georgia. PCBs decreased more than an order of magnitude (14 ppm in 1970 and 0.84 ppm in 2002). DDE decreased (4.07 ppm in 1970 and 1.38 ppm in 2002). PBDEs increased steeply until the mid 1990s (0.0002 ppm in 1979 and 0.39 ppm in 1994), followed by a slower decline (0.063 ppm in 2002). Mercury data were not available.
  8. This chart shows contaminants in Mackenzie River burbot. PCBs show little trend, fluctuating in the range of 0.11 to 0.28 ppm from 1988 to 2008. Total DDT also showed no trend from the mid 1980s to the early 2000s (fluctuating in the range of 0.05 to 0.06 ppm), then showed more variability and some higher peaks (fluctuating in the range of 0.06 to 0.17 ppm in annual measurements from 2002 to 2008). PBDEs increased sharply (0.0004 ppm in 1988 and 0.0052 ppm in 2006) and then declined steeply in the most recent two years of sampling (0.0020 in 2007 and 0.00094 in 2008). Mercury increased (0.22 ppm in 1985 and 0.41 in 2008).

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PCBs in Great Lakes fish

Graphic thumbnail: PCBs in Great Lakes fish

This line graph shows the total PCB concentrations in lake trout (walleye in Lake Erie) in the Great Lakes, from 1972 to 2002. Data are shown for lakes Superior, Huron, Michigan, Erie and Ontario. PCB concentrations in fish declined in all the lakes from the early to mid 1970s to the mid 1980s. The highest PCB concentration was more than 10 parts per million in Lake Michigan lake trout in the early 1970s and the lowest was less than 0.5 parts per million in Lake Superior lake trout in the late 1980s. Since the mid 1980s, PCB levels in Great Lakes fish show slow declines or no trend.

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Contaminants in killer whales off the Pacific Coast

Graphic thumbnail: contaminants in killer whales off the Pacific Coast

This graphic includes bar charts showing the average levels of PCBs and PBDEs in the three populations of killer whales along the B.C. coast from samples taken in the mid 1990s. The charts are accompanied by a map showing the distribution of the three populations. Northern resident whales reach from the coastal border with Alaska to approximately two thirds down the coast of Vancouver Island; the southern resident whales extend from below the northern resident territory through Puget Sound and off the northern Olympic Peninsula. The transient killer whale extends off the entire B.C. coast and through Puget Sound.

Average PCB levels were: transient whales, 250 parts per million; southern residents, 150 parts per million; and northern residents, 40 parts per million. These values are all well above the effects threshold for harbour seals, which is 10 parts per million. This effects threshold is the level at which toxic effects have been detected from PCBs in tests on harbour seals. Average PDBE levels were: transient whales, 1,000 parts per million; southern residents, 975 parts per million; and northern residents, 200 parts per million. Effects thresholds are not known for PBDEs in killer whales or related species.

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