Ads
related to: pcb congeners list of items
Search results
Results From The WOW.Com Content Network
Congener descriptors give a shorthand notation for geometry and substituent positions. The twelve congeners that display all four of the descriptors are referred to as being "dioxin-like", referring both to their toxicity and structural features which make them similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD). [1]
The PCB congener pattern suggested the contamination was from a mixture of Aroclor 1260 and 1254. Over 9 million chickens, and 60,000 pigs were destroyed because of the contamination. The extent of human health effects has been debated, in part because of the use of differing risk assessment methods.
There are 209 PCB compounds. Analogously to PCDDs at least two lateral chlorines in each ring in positions 3,4, and/or 5 are needed for dioxin-like activity. Because the AH receptor requires a planar (flat) structure, only PCB congeners that can rotate freely along the C—C axis between the rings can attach the receptor.
A group of carcinogenic organic compounds, polychlorinated biphenyls (PCBs), is an example of a congener grouping. The number and locations of Cl groups can vary. In chemistry, congeners are chemical substances "related to each other by origin, structure, or function". [1]
The toxicity of PCDDs depends on the number and positions of the chlorine atoms. Congeners that have chlorine in the 2, 3, 7, and 8 positions have been found to be significantly toxic. In fact, 7 congeners have chlorine atoms in the relevant positions which were considered toxic by the World Health Organization toxic equivalent (WHO-TEQ) scheme ...
Congener may refer to: Congener (biology) , organisms within the same genus Congener (chemistry) , related chemicals, e.g., elements in the same group of the periodic table
General structure of a PCB. Polychlorinated biphenyls (PCBs) are various biphenyl based artificial products that are widely used as a dielectric fluid, industrial coolant, and lubricants in the 1960s and 1970s. There is no evidence its synthesis occurs naturally. They are classified as persistent organic pollutants.
Clearance between package body and PCB. H Height of package from pin tip to top of package. T Thickness of pin. L Length of package body only. L W Pin width. L L Pin length from package to pin tip. P Pin pitch (distance between conductors to the PCB). W B Width of the package body only. W L Length from pin tip to pin tip on the opposite side.