Preliminary results from an environmental monitoring program of an industrial submarine outflow are presented. Introduced mussels technique with Perna perna was applied. Two evaluations were carried out; one thirty days after the transplant and, another one, sixty days after the first one. Trace metal bioaccumulation and the associated cellular damage were determined. In the first evaluation, in the beginning of the industrial activity, concentrations significantly higher of some metals in mussels of the area of the emissary in comparison with the control site had been registered. In the second evaluation higher concentrations were recorded only for Cd, Zn and Ni at submarine outflow zone. Despite this, the recorded concentrations remained in the range considered normal for the studied species and below of the maximum level accepted by law for human consumption. The Neutral Red Assay, the biomarker applied, evidenced no cellular damage.