Environment and Climate Change Canada, Wildlife and Landscape Science Directorate, Science and Technology Branch, 801-1550 av d'Estimauville, Québec, Québec G1J 0C3, Canada.
Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, Québec H3C 3P8, Canada.
Sci Total Environ. 2017 Dec 31;609:1270-1285. doi: 10.1016/j.scitotenv.2017.07.223. Epub 2017 Aug 6.
Since 1991, great blue heron (Ardea herodias) eggs have been collected and analyzed for mercury (Hg), persistent organic contaminants (OCs), brominated and non-brominated flame retardants (FRs) as well as stable isotopes δC and δN. In the present study, temporal trends of contaminants were analyzed in eggs sampled in four regions along the St. Lawrence River (Quebec, Canada) and inland sites using new and previously published data. Most contaminants declined significantly over time in most regions. Globally, the highest annual change, -17.5%, was found for pp'-DDD, while the smallest annual decline, -0.54%, was observed for Hg. Concentrations of ΣDDT and ΣFR (sum of 8 congeners) decreased by -11.6% and -7.3%, respectively. Declines in ΣPCBs differed among regions, from -5.6% in the fluvial section to -14.7% in the inland region. The highest concentration of ΣFR was measured in eggs from Grande Ile in the fluvial section of the river in 1996 (2.39μg/g). Stable isotope ratios also showed temporal trends in some regions: δC decreased in the fluvial section and increased in Gulf region, while δN decreased in the fluvial section and increased in the upper estuary. Significant positive relationships were found between ΣDDT, ΣPCBs and ΣFRs and δN and δC in freshwater colonies, but not in estuarine or marine colonies. These results suggest that changes in trophic level and foraging areas over time were influential factors with respect to contaminant burden in great blue heron eggs in the fluvial section, but not in the other regions.
自 1991 年以来，人们收集并分析了大蓝鹭（Ardea herodias）的卵，以检测汞（Hg）、持久性有机污染物（OCs）、溴化和非溴化阻燃剂（FRs）以及稳定同位素 δC 和 δN。在本研究中，利用新的和以前发表的数据，分析了在圣劳伦斯河（加拿大魁北克）沿线的四个地区以及内陆地区采集的卵中污染物的时间趋势。在大多数地区，大多数污染物随时间呈显著下降趋势。在全球范围内，pp'-DDD 的年变化率最高，为-17.5%，而 Hg 的年下降率最小，为-0.54%。ΣDDT 和 ΣFR（8 种同系物的总和）的浓度分别下降了-11.6%和-7.3%。ΣPCBs 的下降在不同地区有所不同，从河流的河流段的-5.6%到内陆地区的-14.7%。在 1996 年，河流的河流段的 Grande Ile 岛上的卵中检测到的 ΣFR 浓度最高（2.39μg/g）。在一些地区，稳定同位素比值也显示出时间趋势：河流段的 δC 下降，海湾地区的 δC 上升，而河流段的 δN 下降，河口上游的 δN 上升。在淡水鸟类栖息地中，ΣDDT、ΣPCBs 和 ΣFRs 与 δN 和 δC 之间存在显著的正相关关系，但在河口或海洋鸟类栖息地中没有。这些结果表明，随着时间的推移，营养水平和觅食区域的变化是影响河流段大蓝鹭卵中污染物负担的重要因素，但在其他地区则不然。
