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Potential Effects of Contaminants on Fraser River Sockeye Salmon

Potential Effects of Contaminants on Fraser River Sockeye Salmon

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glycoproteins, polypeptides, peptides, steroids, modified amino acids, catecholamines,prostoglandins, and retinoic acid. These substances are transported in the blood at lowc<strong>on</strong>centrati<strong>on</strong>s and bind to specific sites <strong>on</strong> cell membranes (i.e., for n<strong>on</strong>-steroidalhorm<strong>on</strong>es) or the nucleus <str<strong>on</strong>g>of</str<strong>on</strong>g> the cells (i.e., for steroidal horm<strong>on</strong>es) <str<strong>on</strong>g>of</str<strong>on</strong>g> the target tissues andorgans. These binding sites, termed receptors, are located throughout the body, are <str<strong>on</strong>g>of</str<strong>on</strong>g>tenlocated far from the gland that produced the horm<strong>on</strong>e. Some <str<strong>on</strong>g>of</str<strong>on</strong>g> the major endocrineglands in fish include the hypothalamus, pituitary gland, thyroid gland, parathyroid gland,pancreas, adrenal gland, ovary, and testes. Some <str<strong>on</strong>g>of</str<strong>on</strong>g> the target organs and tissues underendocrine c<strong>on</strong>trol include mammary glands, b<strong>on</strong>e, muscle, the nervous system, andreproductive organs (Crisp et al. 1998). An overview <str<strong>on</strong>g>of</str<strong>on</strong>g> selected major endocrine glandsand their target tissues is provided in Figure 6.1 (Tarrant et al. 2005).6.1.2 Identificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Endocrine-Disrupting Chemicals in the <strong>Fraser</strong> <strong>River</strong>BasinAn envir<strong>on</strong>mental endocrine disruptor can be described as an exogenous substance ormixture <str<strong>on</strong>g>of</str<strong>on</strong>g> substances that interferes with the synthesis, secreti<strong>on</strong>, transport, binding,acti<strong>on</strong>, or eliminati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> natural horm<strong>on</strong>es and causes an adverse effect <strong>on</strong> themaintenance <str<strong>on</strong>g>of</str<strong>on</strong>g> homeostasis, development, reproducti<strong>on</strong>, or behaviour (Crisp et al. 1998).An endocrine disruptor is c<strong>on</strong>sidered to be any natural substance, synthetic chemical, orchemical mixture that mimics, enhances, or inhibits the acti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> horm<strong>on</strong>es.Endocrine-disrupting chemicals are not a discrete class <str<strong>on</strong>g>of</str<strong>on</strong>g> chemicals. Rather, endocrinedisrupting compounds include a wide variety <str<strong>on</strong>g>of</str<strong>on</strong>g> substances that are released into theenvir<strong>on</strong>ment from natural and anthropogenic sources. While there is no universallyacceptedsystem for identifying or classifying endocrine disrupting compounds, thesec<strong>on</strong>taminants can be classified into a number <str<strong>on</strong>g>of</str<strong>on</strong>g> general categories based <strong>on</strong> their origin orchemical characteristics, including pharmaceuticals and pers<strong>on</strong>al care products, industrialchemicals, pesticides, inorganic and organometallic compounds, and biogenic compounds(MPCA 2008). Each <str<strong>on</strong>g>of</str<strong>on</strong>g> these general categories <str<strong>on</strong>g>of</str<strong>on</strong>g> endocrine disrupting compounds arebriefly described below. In additi<strong>on</strong>, the c<strong>on</strong>taminants in the <strong>Fraser</strong> <strong>River</strong> Basin that areknown or suspected to be endocrine disrupting compounds were identified using thepriority list developed for the European Commissi<strong>on</strong> (BKH C<strong>on</strong>sulting Engineers 2000).Pharmaceutical and Pers<strong>on</strong>al Care Products - This category <str<strong>on</strong>g>of</str<strong>on</strong>g> endocrine disruptingcompounds includes synthetic horm<strong>on</strong>es, over-the-counter medicati<strong>on</strong>s, prescripti<strong>on</strong>drugs, and ingredients found in cosmetics, toiletries, detergents, and cleaning products.Natural steroid horm<strong>on</strong>es (such as estr<strong>on</strong>e, 17ß-estradiol, and estriol) and synthetic76

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