Halogenated aromatic compounds, typified by the polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and diphenylethers (PCDEs), are industrial compounds or byproducts which have been widely identified in the environment and in chemical-waste dumpsites. Halogenated aromatics are invariably present in diverse analytes as highly complex mixtures of isomers and congeners and this complicates the hazard and risk assessment of these compounds. Several studies have confirmed the common receptor-mediated mechanism of action of toxic halogenated aromatics and this has resulted in the development of structure-activity relationships for this class of chemicals. The most toxic halogenated aromatic is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and based on in vivo and in vitro studies the relative toxicities of individual halogenated aromatics have been determined relative to TCDD (i.e., toxic equivalents). The derived toxic equivalents can be used for hazard and risk assessment of halogenated aromatic mixtures; moreover, for more complex mixtures containing congeners for which no standards are available (e.g., bromo/chloro mixtures), several in vitro or in vivo assays can be utilized for hazard or risk assessment.

Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and related compounds: environmental and mechanistic considerations which support the development of toxic equivalency factors (TEFs).

Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and related compounds : environmental and mechanistic considerations with support the development of toxic equivalency factors (TEFs)

Triclosan, a commonly used bactericide found in human milk and in the aquatic environment

(1980). Chlorinated Phenols: Occurrence, Toxicity, Metabolism, And Environmental Impact. CRC Critical Reviews in Toxicology: Vol. 7, No. 1, pp. 1-35.

Chlorinated Phenols: Occurrence, Toxicity, Metabolism, And Environmental Impact

Chlorinated dibenzo-p-dioxins and related compounds in incinerator effluents: A review of measurements and mechanisms of formation

Formation of polychlorinated dibenzo-p-dioxins and dibenzofurans during combustion of a 2,4,5-T formulation

http://www.ahling.se/bengt/ivlrap3/F9.pdf

FORMATION OF POLYCHLORINATED DIBENZO-p-DIOXINS DURING COMBUSTION OF CHLOROPHENOL FORMULATIONS

The use in forestry and agriculture of products derived from 2,4,5—trichloro— phenoxy acids (2,4,5—T), ~j 1, has given rise to much concern during a number of years. The major cause of this concern rose from the findings of the highly toxic 2,3,7,8—tetrachlorodibenzo—p-dioxin (II) as a contaminant 1 ,2 in many of these preparations. Toxicity tests with II have given LD 50 values of 2 kg/kg in guinea pigs, the most sensitive species known, and 3 around 80kg/kg in monkeys. The compound also causes irreversible liver damage and is a potent inducer of enzyme systems. In man exposed to II one symptom is chloracne, a severe skin disease.

http://www.ahling.se/bengt/ivlrap3/F6.pdf

B. Ahling

Papers

Formation of polychlorinated dibenzo-p-dioxins and dibenzofurans during combustion of a 2,4,5-T formulation

FORMATION OF POLYCHLORINATED DIBENZO-p-DIOXINS DURING COMBUSTION OF CHLOROPHENOL FORMULATIONS

FOI~9ATION OFPOLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZO- FURANS DURING CU~'1BUSTION OFA2,'4,5-T FOf~1ULATION