Adapted lead (Pb) histochemical detection procedure in tissue samples of blue crabs Callinectes danae (Smith, 1869)

Abstract

Lead (Pb) cellular deposits can be detected by histochemistry using a classical potassium dichromate - formalin fixation and post-fixation with 3% potassium dichromate solution. Here we describe an alternative procedure for Pb histochemical detection in the blue crab Callinectes danae. Animals were exposed to Pb (2 µg/mL) for 24, 48 and 96h. Then, buffered formalin solution was used for hepatopancreas and gills fixation, with tissue sections incubated in 3% potassium dichromate at 40 °C for seven days. Counterstains were tested with better results reached using 0.5% phloxine and 1% methylene blue dyes. This adapted method favors Pb deposition studies in wildlife animals since it uses ordinary steps for tissue collection and standard histological procedures. Besides, this method is cheaper and simpler than the classical one for lead deposits detection.