Chlorinated dioxins, health effects

Pluim HJ, deVijlder JJM, Olie K, et al. 1993c. Effects of pre and postnatal exposure to chlorinated dioxins and furans on human neonatal thyroid hormone concentrations. Environ Health Perspect 101 504-508. 

According to the Bay Area Air Quality Management District in San Francisco, more than 5.5 million pounds of toxic chlorinated substances are released in the area annually. This includes approximately 13,000 pounds of chloroform, 1.4 million pounds of freon, 2 million pounds of perchloromethylene, and trace amounts of dioxin. (Dioxin is one of the most toxic chemicals known.) A report released in September 1994 by the U.S. Environmental Protection Agency (EPA) clearly describes dioxin as a serious public health threat. The public health impact of dioxin may rival the impact that DDT had on public health in the 1960s. According to the EPA report, not only does there appear to be no safe level of exposure to dioxin, but levels of dioxin and similar chemicals have been found in the U.S. population that are at or near levels associated with adverse health effects. The EPA report also confirmed that dioxin is a cancer hazard, exposure... 

United States because they build up in the environment and can cause harmful health effects, they are still in use in many other countries. Polychlorinated dibenzodioxins and polychlorinated dibenzofurans (dioxins) (Fu et ah, 2003) consist of 210 different compounds that have similar chemical properties (Bhandari and Xia, 2005). This class of compounds is persistent, toxic, and bioaccumulative. They are generated as by-products during incomplete combustion of chlorine containing wastes such as municipal solid waste, sewage sludge, and hospital and hazardous wastes (Bhandari and Xia, 2005). PCBs were widely used in the past and now contaminate many industrial and natural areas. 

Several countries have introduced stringent emission limits (0.1 ng-TE/Nm ) for chlorinated dioxins and furans emitted from combustion sources, in particular solid waste incinerators, because of concerns over their adverse health effects. Technologies for reducing their formation and emission in incineration processes have been studied extensively and can be applied in modern incineration plants. Activated carbon injection and fabric filtration are currently practiced in many installations. However, to minimize capital cost, a more fundamental approach is needed to control and limit formation of these pollutants in incineration processes, e.g., involving the postcombustion zone, the combustion chamber, and waste feeding. ... 

The findings of the chlorinated dibenzo-p-dioxin and dibenzofuran isomers in persons residing in contaminated areas and both measured and calculated levels of these compounds in breast milk in the United States presents a possible cause for concern regarding health effects in the nursing infant. Further study is indicated to determine if there is any real clinical risk at the levels found. 

Strength as an oxidizing agent. There is, however, pressure to reduce the use of chlorine gas and organochlorine compounds, because they can lead to the environmental release of chlorinated hydrocarbons, which may cause cancer and other kinds of adverse health effects. The danger compounds include the notorious dioxin (Structure 6.2), which is a degradation product of organochlorine pesticides and other similar compounds. 

The detection of a potent dioxin impurity in a major herbicide has focused attention on the nature of chlorinated impurities in pesticides, and in a larger sense, impurities in all chlorinated industrial compounds used extensively in man s environment. The present 2,4,5-T controversy is overshadowed by the dioxin problem. Major disagreement still exists on their relative contributions to the teratogenic effects observed in chicks and the validity of interpretation of high dosage rates used to achieve these effects. We have avoided any assessment of the health-related aspects of dioxins but have dealt almost exclusively with dioxins as an environmental entity. 

Dioxins are of concern because they accumulate in the biosphere, where they have highly deleterious effects. Tests have shown that when the concentration of dioxins in the blood of laboratory animals reaches a critical level, reproductive and immune system defects result. Moreover, recent data indicate that the concentration of dioxins in the blood of the average U.S. resident has nearly reached that level. A major reason is that dioxins are not veiy water-soluble, so they accumulate in the body rather than being readily processed and excreted. Consequently, several groups, including the American Public Health Association, have issued calls for phasing out the use of industrial chlorine. 

Although the effects of chronic exposure of humans to low levels of POPs are difficult to predict, some biological effects have been described. For example, exposure of children to PCBs and PCDD/Fs may be linked to an elevated risk for infectious diseases. Exposure of pregnant women to PCDD/Fs may cause lower fertility in their male offspring. The adverse effects to human health of acute and chronic exposure of high concentrations of POPs, especially among industrial workers exposed to daily intakes of chemicals, are more evident. Elevated concentrations of DDE and TCDD have been associated with the development of cancers such as breast cancer, leukaemia and thyroid cancer. Dioxin exposure may also be associated with immunotoxicity, reproductive diseases and neurotoxicity. Extreme exposure to chlorinated compounds has resulted in death [101]. 

This public health statement tells you about chlorinated dibenzo-p-dioxins (CDDs) and the effects of exposure. 

CAS = Chemical Abstracts Services CDDs = chlorinated dibenzo-p-dioxins DOT/UN/NA/IMCO = Department of Transportation/United Nations/North America/lnternational Maritime Dangerous Goods Code EPA = Environmental Protection Agency HSDB = Hazardous Substances Data Bank NCI = National Cancer Institute NIOSH = National Institute for Occupational Safety and Health OHM/TADS = Oil and Hazardous Materials/Technical Assistance Data System RTECS = Registry of Toxic Effects of Chemical Substances... 

KerkvlietNI. 1995. Immunological effects of chlorinated dibenzo-p-dioxins. Environ Health Perspect 103 47-53. 

Ramel, C. 1977. Chlorinated Phenoxy Acids and Their Dioxins Mode of Action, Health Risks, and Environmental Effects. Swedish Natural Science Research Council, Stockholm. 

Unfortunately, PCP often contains impurities that are toxic not only to fungi and bacteria but also to other living organisms. Its environmental impact includes effects on human health as well as on plants and other environmental organisms, such as aquatic species and wildlife. Its impurities include the less chlorinated phenols, polychlorinated phenoxy phenols, polychlorinated dibenzo-p-dioxins, and polychlorinated furans. By the late 1980s, pentachloro-phenol and its impurities had become so ubiquitous in the environment that its use has now been restricted. 

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