The role of earthworm defense mechanisms in ecotoxicity studies

Abstract

Earthworms are important soil organisms that affect the soil structure by influencing organic and inorganic matter breakdown. Earthworms are in permanent contact with soil particles via their permeable skin and digestive tract and are thus strongly affected by pollutants present in the soil. Earthworms often live in very hostile environments with an abundant microflora and therefore have developed very potent defense mechanisms. These mechanisms have been described to be influenced by various types of organic and inorganic pollutants and also by the nanoparticles that reach the soil system. Reduced abilities of earthworms to protect themselves against pathogenic microorganisms result in lower reproduction rates and increased mortality. In this review, a summary of the up-to-date data describing the effects of contaminants on the natural defense barriers and immune system of earthworms is presented.