Endocrine disrupting compounds in the coastal environment
Endocrine disrupting compounds (EDCs) have been shown to have a negative impact on both humans and wildlife. This article examines the various types of EDCs and the impact that these EDCs can have on the coastal environment, particularly within the North Sea, Baltic Sea and Mediterranean Sea.
Many pollutants in the aquatic environment have received significant attention due to their potential estrogenic effects and are classified as endocrine disrupting compounds (EDCs). Endocrine disruptors are defined as exogenous substances or mixtures that alter the function(s) of the endocrine system and consequently cause adverse health effects in organisms, their progeny or (sub) population.  
Mechanisms of estrogenic action
- mimic or antagonize the action of endogenous hormones,
- interfere with the synthesis, metabolism, transport and excretion of natural hormones
- alter the hormone receptor levels.
Effects on wildlife and humans
The occurrence of EDCs in the environment may pose adverse health effects, reproductive abnormalities and impaired development in wildlife species. Effects of endocrine disruption have been reported in snails, mussels, crustaceans, fish, reptiles, birds and mammals.    Moreover there is a lot of discussion about possible adverse effects to humans. EDCs have been suggested as being responsible for changes in human health and reproduction (decline in sperm counts and quality, impotence, increased incidence of genital abnormalities and increased incidences of certain types of cancer) observed over recent decades.  
Endocrine Disrupting Compounds
EDCs comprise of naturally produced hormones and man-made compounds.  The first category includes endogenous hormones such as estrogens, progesterone and testosterone produced in mammals, phytoestrogens like isoflavones present in many plants and mycoestrogens produced from fungi. Man-made chemicals include synthetic hormones and industrial chemicals. Synthetic hormones are used as oral contraceptives, in hormone replacement treatment and as animal feed additives. Industrial chemicals include numerous compounds produced for diverse purposes and may exhibit sex hormone-like activities. Such compounds have been found in certain chemical classes e.g. phenols, halogenated substances and phthalates. Among the phenolic compounds produced by chemical industry, two classes, alkylphenols and bisphenols, present scientific and public interest as potential EDCs. Both are produced in large quantities and eventually released into the environment. Alkylphenols are either used directly e.g. as antioxidants or released from alkylphenol polyethoxylates widely used as cleaning agents in the textile and plastic industry, for household and personal care items and in agriculture. The prototype of bisphenols, bisphenol A, is used in the production of polycarbonate plastics and epoxy resins. Polychlorinated compounds that show estrogenic activity are certain chlorinated pesticides (e.g. DDT, dieldrin, endosulfan), polychlorinated biphenyls (PCBs), especially their hydroxylated metabolites and their conjugates, polychlorinated dibenzo(p)dioxins and dibenzofurans (PCDD/Fs). Organotin compounds have been widely used as antifouling biocides. They have been described as among the most harmful substances knowingly introduced onto the marine environment. In aquatic invertebrates, particularly marine gastropods, organotin compounds, such as tributyltin (TBT) and triphenyltin (TPT), induce irreversible sexual abnormality in females which is termed "imposex", at very low concentrations. Another class of widely used industrial chemicals that are potential EDCs are phthalates, produced and applied to plastics, cosmetics, adhesives, paints etc. Moreover, many compounds are under investigation since they are suspected to have estrogenic activity.
The analytical procedure for the determination of EDCs from environmental samples includes isolation of the target compounds through various extraction techniques and determination by employing mainly liquid or gas chromatography coupled to mass spectrometry (GC-MS, GC-MS/MS, LC-MS, LC-MS/MS).  Furthermore, bioassays based on various mechanisms (cell proliferation, ligand binding, vitellogenin induction, luciferase induction, antigen-antibody intervention) provide substantial information on the estrogenic activity of environmental samples. 
EDCs in European coastal environment
EDCs enter marine environment through discharges of industrial and sewage wastewater, emissions from various marine activities, oil spills or indirectly through rivers, streams and canals. For this reason, the higher concentrations of EDCs are usually found close to sewage impacted areas, harbors and river estuaries. A multitude of studies has indicated the occurrence of EDCs in European coastal environment at potentially toxic levels. EDCs were found in seawater, sediments and suspended solids in the Mediterranean Sea     , Baltic Sea  and North Sea.    Moreover, EDCs were also found in various marine species, invertebrates and vertebrates such as molluscs, crustaceans and fish.    
The Water Framework Directive 2000/60/EC establishes a framework for the protection of inland surface waters, transitional waters, coastal waters and groundwater.  The aim of this Directive is to prevent further deterioration of the aquatic environment and to protect the status of aquatic ecosystems through specific measures for the progressive reduction of discharges, emission and losses of priority substances. Among chemical pollutants of particular concern are endocrine disrupters (Annex VIII-group 4). Thus, the Member States have to take action to prevent human exposure to endocrine disrupting substances through contaminated water resources.
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