Polyhalogenated compounds (PHCs) are any compounds with multiple substitutions of

halogen The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this grou ...

s. They are of particular interest and importance because they

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

in humans, and comprise a superset of which has many toxic and carcinogenic industrial chemicals as members. PBDEs, PCBs, dioxins (PCDDs) and PFCs are all polyhalogenated compounds. They are generally non-

miscible Miscibility () is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration), forming a homogeneous mixture (a solution). The term is most often applied to liquids but also applies ...

in organic solvents or water, but miscible in some

hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

from which they often derive.

Uses

PHCs are used in a vast array of manufactured products, from wood treatments to cookware coatings, to non-stick, waterproof, and fire-resistant coatings, cosmetics, medicine, electronic fluids, food containers, and wrappings, in everything from

furniture Furniture refers to movable objects intended to support various human activities such as seating (e.g., stools, chairs, and sofas), eating ( tables), storing items, eating and/or working with an item, and sleeping (e.g., beds and hammocks) ...

and furnishings,

automobiles A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

, airplanes,

plastics Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptabi ...

clothing Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin sheets of materials and natura ...

and cloth, surgery, insulation, adhesives, paints, sealants, lubricating oils, polyurethane foams, cancer therapy, and medical imaging. They are also heavily used in

pest control Pest control is the regulation or management of a species defined as a pest; any animal, plant or fungus that impacts adversely on human activities or environment. The human response depends on the importance of the damage done and will range ...

Safety

PHCs include notoriously dangerous substances, including

Agent Orange Agent Orange is a chemical herbicide and defoliant, one of the "tactical use" Rainbow Herbicides. It was used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. It ...

, DDT, and other

pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and la ...

. Many non-pesticide PHCs have the same safety issues as pesticides.

Types

* Polycholorinated, e.g. PCBs, dioxins (PCDDs), hexachlorophene, dibenzofurans (PCDFs),

polychloro phenoxy phenol Polychloro phenoxy phenols (polychlorinated phenoxy phenols, PCPPs) are a group of organic polyhalogenated compounds. Among them include triclosan Triclosan (sometimes abbreviated as TCS) is an antibacterial and antifungal agent present in som ...

s (PCPPs),

polychlorinated diphenyl ethers Polychlorinated diphenyl ethers (PCDEs) are structurally similar to polychlorinated biphenyls (PCBs), both which may be toxic polyhalogenated compounds and some PCDE congeners have been reported to cause toxic responses similar to those caused by ...

(PCDEs). * Polybrominated, e.g., PBDEs, polybrominated biphenyls (PBBs). *

Perfluorinated compounds A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound containing only carbon-fluorines and C−C bonds, as well as potentially heteroatoms. Perfluorinated compounds have properties that result from the presence of flu ...

* Polyiodinated compounds

Breakdown of compounds

Despite bioaccumulating in humans, patents have been filed for removal of halogen by electrolysis during manufacturing, though toxic chlorinated compounds may be created as byproducts of chlorinated compounds. Another method during manufacture is to use anaerobic bacteria

References

{{HealthIssuesOfPlastics Organohalides