Selenium concentrations were measured in water, sediments and organisms inhabiting a freshwater coal power station cooling reservoir. Se concentrations found were: water, 1.9 ± 2 μg L^–1; sediment, 7 ± 1 μg g^–1; phytoplankton, 3.4 μg g^–1; zooplankton, 5.3 μg g^–1; epiphytic algae, 1.3 ± 0.2 μg g^–1; benthic algae, 8 ± 2 μg g^–1; macrophyte leaves, 2.7–2.8 μg g^–1; macrophyte roots, 0.5–6.5 μg g^–1; detritus, 10 μg g^–1; Oligochaeta, 11 μg g^–1; Corbiculidae, 1.1 μg g^–1; Insects, 3.7–8.3 μg g^–1; Gastropoda, 3.2 μg g^–1; Crustacea, 3.1–6 μg g^–1; whole fish, 2.2–13 μg g^–1; and fish liver, 134–314 μg g^–1. Bioconcentration factors were similar to those found in aquatic ecosystems with comparable Se concentrations in the water column. A food web was constructed with four main food chains (phytoplankton, epiphytic algae, benthic algae and sediment/detrital), with fish fed from multiple pathways. Biomagnification only occurs along food chains for flathead gudgeons and rainbow trout. Se concentrations in food sources were above the 3 μg g^–1 dietary Se level considered to induce teratogenesis in fish spawning. Flathead gudgeons were found to be suffering teratogenesis and rainbow trout showed no evidence of teratogenesis.