Analytical results are reported for the determination of heavy metals in environmental matrices, sampled in an ecosystem inside a protected area: the Park of the Po Delta, located near the thermoelectric power station ENEL of Porto Tolle, one of the greater in Italy. The elements determined, in sediments and superficial water, are Ni and V, linked to the fuel oil combustion. However, in order to obtain a complete picture enough of heavy metals polluting load in the study areas, the following elements: Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn are also determined. For all the elements, in addition to the detection limits, precision and accuracy are also given: the former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.