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There are 209 different chemical compounds in which one to ten chlorine atoms can replace hydrogen atoms. PCBs are typically used as mixtures of compounds and are given the single identifying CAS number 1336-36-3. About 130 different individual PCBs are found in commercial PCB products. [11]: 2 Toxic effects vary depending on the specific PCB.
German dioxin incident: In January 2011 about 4700 German farms were banned from making deliveries after self-checking of an animal feed producer had showed levels of dioxin above maximum levels. This incident appeared to involve PCDDs and not PCBs. [17] Dioxins were found in animal feed and eggs in many farms.
Ortho-PCBs may alter hormone regulation through disruption of the thyroid hormone transport by binding to transthyretin. [8] Coplanar PCBs are similar to dioxins and furans, both bind to the aryl hydrocarbon receptor (AhR) in organisms and may exert dioxin-like effects, in addition to the effects shared with non-coplanar PCBs.
The AH receptor is phylogenetically highly conserved, with a history of at least 600 million years, and is found in all vertebrates. Its ancient analogs are important regulatory proteins even in more primitive species. [8] In fact, knock-out animals with no AH receptor are prone to illness and developmental problems. [8]
Dioxins and dioxin-like compounds (DLCs) are a group of chemical compounds that are persistent organic pollutants (POPs) in the environment.They are mostly by-products of burning or various industrial processes or, in the case of dioxin-like PCBs and PBBs, unwanted minor components of intentionally produced mixtures.
The analysis found 66, or 14%, of all active ingredients in pesticides are PFAS, which are intentionally added to improve the product’s ability to eliminate pests, Andrews said.
Exposure to the coplanar stereoisomer 3,3',4,4',5,5'-hexabromobiphenyl (but not the non-coplanar stereoisomer) in genetically susceptible mice is known to cause immunotoxicity and disorders related to the central nervous system, and even at doses as low as 2.5 mg/kg, excess neonatal fatalities are observed (LD 50 is from 5–10 mg/kg). [1]
Microbial biodegradation is the use of bioremediation and biotransformation methods to harness the naturally occurring ability of microbial xenobiotic metabolism to degrade, transform or accumulate environmental pollutants, including hydrocarbons (e.g. oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), heterocyclic compounds (such as pyridine or quinoline ...