User:Gpedro174/Aquatic toxicology

The aquatic environment is susceptible to a lot of pollution due to improper disposure of chemicals, agriculture run off and other phenomena. The introduction of chemicals into an aquatic environment can change the system in various ways. When considering chemicals introduced into aquatic systems it is important to consider biomagnification and bioaccumulation. Chemicals coming into a system become food web relevant when they enter the tissues of animals through the food web, Biomagnification is when these outside chemicals coming from pollution travel up the food web while bioaccumulation is when chemicals accumulate in the tissues of said organisms. Endocrine disrupting chemicals (EDCs) are chemicals found in various wastes and pollutants (examples: pesticides and industrial chemicals) and when entering bodies of water can harm many of the biota through the processes of bioaccumulation and biomagnification.. These chemicals can mimic the function of natural hormones in animals and cause havoc to the endocrine system. They can either bind to hormone receptors and act as if they are the natural hormone creating a cascade of reactions when not needed or they can block the receptor and not allow for the original hormone to bind. There are many things that have been linked to endocrine disrupting chemicals such as gamete quality, reproductive physiology, inhibition of gametogenesis, development of intersex gonads, decreased fertility and abnormalities in sperm. Wastewater treatment plants in Portugal have shown high concentrations of natural and synthetic estrogens in the country’s wastewater treatment plant. When talking about many organisms in the aquatic environment sometimes their sexual differentiation will be determined by environmental factors. This puts a lot of concern of things that are entering the aquatic environment that should not be present and ultimately, they could influence or override the genetic factors that sometimes also contribute to this sexual differentiation. Natural or synthetic estrogens lurking in the water could be shaping different organism and disrupting the development and behaviors of them. Behavior is also something that can be affected by estrogens because it has been shown that increased aggression has a correlation with high estrogen levels in the animal kingdom. There have been studies that have shown that these endocrine disrupting chemicals accumulate in the sediment. Increased female proportion and sometimes a lack of males have been observed in fish population downstream of wastewater treatment facilities. These estrogens can affect fish populations in many negative ways by effecting their development, behavior and reproduction. When situations like this occur, it is important to consider the entire species of fish in that aquatic body because since these estrogens are causing major disruptions, they could potentially interfere with species of fish that are endangered, threatened or keystone species in that ecosystem. Environmental estrogens can interfere with various pathways in molecular biology as was well and have been seen to interfere with many signal transduction pathways. In conclusion environmental estrogens can contribute to problems in development, sexual differentiation, feminization and behavior changes in aquatic organisms. Not only is the aquatic organism harmed but the aquatic ecosystem can suffer tremendously as well by the presence of estrogens that make themselves into the body of water.