Maul Jonathan D, Belden Jason B, Schwab Becky A, Whiles Matt R, Spears Brian, Farris Jerry L, Lydy Michael J
Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, Illinois 62901, USA.
Environ Toxicol Chem. 2006 Apr;25(4):1017-25. doi: 10.1897/05-309r.1.
Insectivorous passerines often bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) frequently are used for estimating PCB bioaccumulation, yet the focus on specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 +/- 15.93 microg/kg) to tree swallow nestlings (2,827.76 +/- 505.67 microg/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and for male and female Chironomus spp. For nestlings, the highest BSAF was for the mono-ortho-substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp., suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and, on a PCB congener pattern basis, may have been influenced by other taxa, such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, the present study suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines.
食虫性雀形目鸟类常常通过营养级传递过程生物累积多氯联苯（PCBs）。树燕（Tachycineta bicolor）常被用于估算多氯联苯的生物累积情况，然而，对于受污染沉积物与鸟类之间特定营养级联系的关注却十分有限。本研究通过同时检测水生和陆生昆虫以及雏鸟肠道内容物中的多氯联苯，重点关注营养级途径，研究了多氯联苯从沉积物到树燕的生物累积情况。总多氯联苯浓度从沉积物（123.65±15.93微克/千克）增加到树燕雏鸟（2,827.76±505.67微克/千克），水生昆虫、陆生昆虫和肠道内容物样本的浓度处于中间水平。树燕雏鸟以及雄性和雌性摇蚊属的生物群-沉积物累积因子（BSAFs）在不同同系物之间存在差异。对于雏鸟来说，最高的BSAF是单邻位取代的同系物118。雏鸟肠道内容物和雌性摇蚊属的生物放大值相似，表明这种食物可能是多氯联苯向雏鸟整体转移的主要贡献者。然而，肠道内容物样本的变异性很大，并且基于多氯联苯同系物模式，可能受到了其他类群的影响，比如陆生昆虫。考虑到许多食虫性鸟类的饮食可塑性，本研究表明，在研究食虫性雀形目鸟类的多氯联苯累积情况时，应考虑多种潜在的食物来源。
