Department of Zoology, Michigan State University, East Lansing, MI, 48824, USA.
Environ Monit Assess. 2011 Jan;172(1-4):91-112. doi: 10.1007/s10661-010-1319-5. Epub 2010 Feb 10.
Dietary exposure of house wrens (Troglodytes aedon), tree swallows (Tachycineta bicolor), and eastern bluebirds (Sialia sialis) to polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) near Midland, Michigan (USA) was evaluated based on site-specific data, including concentrations of residues in bolus samples and individual invertebrate orders and dietary compositions by study species. Site-specific dietary compositions for the three species were similar to those reported in the literature, but differed in their relative proportions of some dietary items. Oligocheata (non-depurated) and Brachycera (Diptera) contained the greatest average concentrations of ΣPCDD/DFs of the major site-specific dietary items collected via food web-based sampling. Average ingestion values of ΣPCDD/DFs from site-specific bolus-based and food web-based dietary concentrations for nestlings at study areas (SAs) were 6- to 20-fold and 2- to 9-fold greater than at proximally located reference areas (RAs), respectively. Average ingestion values of total 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ(WHO - Avian)) from site-specific bolus-based and food web-based dietary concentrations for nestlings at SAs were 31- to 121-fold and 9- to 64-fold greater than at proximally located RAs, respectively. Estimates of ΣPCDD/DFs and TEQ(WHO - Avian) tissue concentrations based on nestling dietary exposures were greater than those measured. Plausible explanations include nestling metabolism of 2,3,7,8-tetrachlorodibenzofuran and assimilation rates of less than the 70% assumed to occur over the nestling growth period. Profiles of the relative concentrations of individual PCDD/DF congeners in samples of invertebrates and bolus at SAs on the Tittabawassee River downstream of the source of contamination were dominated by 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (22% to 44%) and 2,3,7,8-tetrachlorodibenzofuran (18% to 50%).
基于特定地点的数据，评估了密歇根州米德兰市（美国）附近的家雀（Troglodytes aedon）、树燕（Tachycineta bicolor）和东方蓝鸟（Sialia sialis）对多氯二苯并呋喃（PCDFs）和多氯二苯并二恶英（PCDDs）的饮食暴露情况，这些数据包括胃容物样本中的残留浓度以及研究物种的个体无脊椎动物等级和饮食组成。这三种物种的特定地点饮食组成与文献中报道的相似，但某些饮食项目的相对比例有所不同。寡毛纲（未净化）和双翅目（蝇类）在通过食物网采样收集的主要特定地点饮食项目中含有最大的ΣPCDD/DF 平均浓度。从研究区域（SA）的特定胃容物和食物网基于饮食浓度计算的巢幼鸟 ΣPCDD/DF 摄入量值分别比靠近的参考区域（RA）高 6 到 20 倍和 2 到 9 倍。从研究区域（SA）的特定胃容物和食物网基于饮食浓度计算的巢幼鸟总 2,3,7,8-四氯二苯并二恶英等效物（TEQ（WHO-鸟类））摄入量值分别比靠近的参考区域（RA）高 31 到 121 倍和 9 到 64 倍。基于巢幼鸟饮食暴露情况估算的 ΣPCDD/DF 和 TEQ（WHO-鸟类）组织浓度估计值大于实际测量值。合理的解释包括 2,3,7,8-四氯二苯并呋喃在巢幼鸟体内的新陈代谢以及在巢幼鸟生长期间假定的同化率低于 70%。在受污染源头下游的蒂塔巴瓦西河 Tittabawassee 河 SA 的无脊椎动物样本和胃容物中，个别 PCDD/DF 同系物的相对浓度分布以 1,2,3,4,6,7,8,9-八氯二苯并二恶英（22% 到 44%）和 2,3,7,8-四氯二苯并呋喃（18% 到 50%）为主。
