Wetlands / Environmental Monitoring / Water Pollution / STEROIDS / Multidisciplinary / Portugal / Cortisol / Liver / Animals / Heavy Metal / Thyroxine / European eel / Water Use / Anguilla anguilla / Fresh water / The Endocrine System Function / Biological markers / Anguilla / Thyroid Stimulating Hormone / Alanine Transaminase / Portugal / Cortisol / Liver / Animals / Heavy Metal / Thyroxine / European eel / Water Use / Anguilla anguilla / Fresh water / The Endocrine System Function / Biological markers / Anguilla / Thyroid Stimulating Hormone / Alanine Transaminase