The document contains data from water sampling in the Gualeguaychú River from 2006 to 2009, measuring levels of heavy metals including lead, cadmium, chromium, iron, nickel, mercury, manganese, zinc, cobalt, vanadium, molybdenum, palladium, and silver. It shows the average concentrations of each metal for each year as well as the overall average across all four years. It also breaks the data down by trimester for each metal in each year.