The As concentration was significantly higher in water at Chasicó Lake, while Pb was higher in water from de la Plata River. Based on the Argentinean National Guidelines for the Aquatic Biota Protection (NGABP), the As concentration in water from the Chasicó Lake and Adela and Barrancas Lagoons, along with the Pb concentration in water from de la Plata River, were above the recommended levels (15 μg L− 1 and 1.6 μg L− 1, respectively). Based on the Canadian Guidelines for the Aquatic Biota Protection, the As concentration was above the recommended maximum level (5 μg L− 1) in all sampling sites except de la Plata River. Furthermore, the Pb concentration was below the recommended maximum value (1 μg L− 1) only for the Chasicó Lake.