Patterns of bioaccumulation of polychlorinated biphenyls (PCBs) by chironomid larvae (Chironomus riparius Meigen) were studied under laboratory conditions. Larvae were maintained for 20 days, separately in two batches of natural bottom sediments sampled from Rybinsk Reservoir (Russia), each differing in PCB content (425.6 μg / kg or 24.8 μg / kg dry weight, respectively). The study revealed that chironomid larvae accumulated PCBs at levels comparable to the PCB content measured in sediments from each exposure. The bioaccumulation coefficient (1.11 and 1.59, respectively, as per dry weight for compared sediment batches) depended directly on the sum PCB content in sediments. At high sediment PCB content, the ratios of homologous groups of PCBs in larvae and sediment were identical and corresponded to the Aroclor 1254 congeners profile; at lower PCB content, pronounced differences were revealed. In larvae, the ratios of 3, 4, 5, and 6CB homologues were evenly distributed at levels of 20–34 %, while the 4CB homologues prevailed (47 %) in sediments. The content of the latter compounds in larvae was lower than in sediments, and higher for the other homologous groups. The study indicates selective bioaccumulation of various homologous groups of PCBs under conditions of low sediment PCB content.

摇蚊幼虫 ( Chironomus riparius ) 对多氯联苯 (PCB) 的生物积累模式Meigen）在实验室条件下进行了研究。幼虫分别在从 Rybinsk 水库（俄罗斯）采样的两批天然底部沉积物中保持 20 天，每批的 PCB 含量不同（分别为 425.6 μg/kg 或 24.8 μg/kg 干重）。研究表明，摇蚊幼虫积累的多氯联苯的水平与每次接触沉积物中测得的多氯联苯含量相当。生物累积系数（分别为 1.11 和 1.59，按比较沉积物批次的干重计算）直接取决于沉积物中 PCB 的总含量。在沉积物 PCB 含量高的情况下，幼虫和沉积物中 PCB 同源组的比例相同，与 Aroclor 1254 同源物分布图一致；在较低的 PCB 含量下，显示出明显的差异。在幼虫中，3、4、5、和 6CB 同系物以 20-34% 的水平均匀分布，而 4CB 同系物在沉积物中占优势（47%）。后一种化合物在幼虫中的含量低于在沉积物中的含量，而在其他同源群体中则较高。该研究表明，在低沉积物 PCB 含量的条件下，各种同系 PCB 的选择性生物积累。