Histological Biomarkers in Fish as a Tool in Ecological Risk Assessment and Monitoring Programs: a Review

Water contamination, both in freshwater and marine ecosystems, has been a serious environmental problem all over the world in the last few decades. One of the most common anthropogenic pollutants, which enter the water bodies are metals and metalloids with no biological functions (As, Cd, Hg, Ni and Pb), pesticides and other persistent organic pollutants such as PAHs, PCBs, tributil tins, dioxins, etc. Most of these pollutants tend to accumulate in biota, biomagnify in the food chains and they are also difficult to break down to less harmful substances. In order to better understand the negative effects on living organisms, and particularly fish, biomarkers at different levels (cell, tissue, organism and population) are applied. In addition, the biomarkers at tissue level such as histological alterations in different fish organs give valuable information about the xenobiotic impact. Thus, they are recommended as useful biomarkers in eco-toxicological research, risk assessment and monitoring programs. In the present paper we aimed to review the use of histological alterations in fish organs such as gills, liver and kidney in ecotoxicological studies, based on collected scientific data from the late