Soil, aquatic biota (moss: Brachythecium rivulare; aquatic macrophytes: Juncus effusus, Potamogeton crispus; fish: Salmo trutta fario, Anguilla anguilla, Phoxinus phoxinus, Chelon labrosus) and sediment samples from the Urumea river valley were analysed for metals by acid digestion and atomic absorption spectroscopy. The sediments show the presence of metal pollution (Cd: 2.5–24 mg kg−1; Pb: 125–1,150 mg kg−1; Zn: 125–2,500 mg kg−1) because mining and industrial wastes. A selective retention of dense minerals in dam sediments contributes to the load of metal, but interstitial water analysis (Cd: <0.02–0.1 mg L−1; Pb: 0.3–1.0 mg L−1; Zn: <0.05–0.6 mg L−1) shows that precipitation equilibrium controls their mobilisation. Biota samples show evidence of metal accumulation, moss reaching 1,100 mg kg−1 in lead and 6,800 mg kg−1 in zinc. Soil from the valley is polluted by both, river carried material and industrial sources (Cd: 1.0–4.0 mg kg−1; Pb: 26–1,120 mg kg−1; Zn: 105–1,390 mg kg−1), but they are used, indistinctly, for farming and pasture.