Polychlorinated biphenol. PCB

In January and March of 1988, Radian Corporation made a comprehensive series of performance measurements on the air pollution control system at Modesto (47). As shown in Table 12, the measurements included chlorinated dibenzo-p-dioxins (CDD), chlorinated dibenzofurans (CDF), polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenols (PCB), total hydrocarbons (THC), ammonia, NOx, sulfur trioxide, sulfur dioxide, hydrochloric acid, carbon monoxide, and particulate matter. 

Compounds that are endocrine disrupters include natural animal hormones released into the environment, plant toxins or phytoestrogens, synthetic hormones present in sewage water and used for medical treatment (e.g., diethylstilbestrol), and several chemicals, including some pesticides and polychlorinated biphenols (PCBs). Endocrine disrupters enter the environment often as a by-product of many chemical and manufacturing processes and through waste disposal routes. Some evidence now suggests that effects of thyroid hormones and the immune system occur in addition to the disruptions of hormones that play a major part in the control of reproduction and development. 

Not all of the evidence was sound because the early analytical methods for DDT using gas chromatography could confuse PCBs (polychlorinated biphenols) and DDT breakdown products, ffowever, these analyses alerted scientist and the public to the widespread contamination of the environment with PCBs (widely used in electrical transformers and other industrial equipments at that time but subsequently banned), which became a new concern. 

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