Morphological, compositional and ultrastructural changes in the Scrobicularia plana shell in response to environmental mercury - An indelible fingerprint of metal exposure?

► Scrobicularia plana shell exhibited an indelible fingerprint of metal exposure. ► Shells collected from R site exhibited sheet like morphology. ► Shells at H site showed large surface area, ruptured organic matrix and crack-like gaps. ► Nacre dimple like morphology appeared due to mercury contamination. ► Ca element replacement from nacre composite was the possible explanation.