Why were elevated PCB concentrations found in fish tissue and not in sediment?
Fish are repeatedly exposed to contamination through different routes, including direct contact with contaminated sediment and consumption of contaminated plant or animal material. PCBs biomagnify, meaning they increase in concentration at higher levels in the food chain (for example, predators at the top of the food chain will have the highest levels, especially older fish). Two important factors contribute to the high detection of PCBs in the Study Unit: PCBs are hydrophobic (not very soluble in water) and strongly lipophilic (have an affinity for lipids, or fats). PCB concentrations can be fairly high in sediments that are high in organic-matter or clay content.
