Molluscan kidneys are able to excrete solids in the urine in the form of concretions.
It is thought that increased formation of these concretions occur under pollutant, environmentally or reproductive induced stress. Light microscopic histopathological analysis of the PCP-exposed P. corneus revealed significantly enhanced production of the kidney concretions when compared to the kidneys of control individuals. Measurements of the number of kidney concretions, the apparent area of the concretions, and the epithelial area filled with concretions indicated an increase in the number and size of concretions in all treated snails. Lipofuscin content of excretory cell concretions was detected.