Toxic substances contamination from

A consistent pericardial edema in chickens gave rise to the term chick edema disease (chick edema factor) (I). Two known outbreaks of the disease in the broiler industry resulted in a great loss of chickens. A lipid residue from the manufacturing fatty acids, being used as a feed ingredient, was a principal source of the toxic substance. Contamination of the lipid component with polychlorodibenzo-p-dioxins was attributed as the causal agent. 

Solvent extraction uses an organic solvent to extract toxic substances from contaminated liquid or solid.67 Examples can be found in the section dealing with the treatment of contaminated soil. 

The WFD, so far, has identified 33 priority hazardous pollutants (PHS), for which Environmental Quality Standards (EQS) have been set. To some extent, these EQS can be met through the establishment of emission control measures. These PHS may originate from several different sources and activities. The main sources of toxic substances to water bodies in Europe may be categorised as agriculture, sewage treatment plants, urban runoff, industry, contaminated lake/ river sediment, soils and landfills. Input via atmospheric transport and deposition has also been identified as an important source both far from and close to source areas. Many of the PS are today banned in Europe, but due to their persistence they are still present in the environment [30]. 

Dioxin. Two years ago, EPA promulgated a rule prohibiting Vertac Chemical Corporation from disposing of waste contaminated by dioxin. Other parties intending to dispose of similarly contaminated wastes were required to notify EPA 60 days in advance of their intentions. This order may have prevented some exposure to this highly toxic substance, though the human health impact of this single prohibition cannot be calculated. 

The most common route of human exposure to di(2-ethylhexyl) phthalate is through food contamination. The average daily exposure from food in the United States has been estimated to be about 0.3 mg/day per individual, with a maximum exposure of 2 mg/day (WHO, 1992 Agency for Toxic Substances and Disease Registry, 1993). 

Emission Standard A quantitative limit on the emission or discharge of a potentially toxic substance from a particular source. Tire simplest system is uniform emission standard where the same limit is placed on all emissions of a particular contaminant. 

Off-site waste disposal methods involve the transfer of solvent wastes to an alternative location before their treatment, reuse, or release into the environment. One such method commonly used both on- and offsite is incineration. Solvent wastes are often incinerated, especially when they contain toxic substances and pose long-term EHS risks if directly released. The process of waste incineration releases a large amount of CO2 into the environment, but often the heat generated from this process may be recovered for use within a plant. When contaminated... 

The dehalogenation process has been approved by the EPA s Office of Toxic Substances for PCB treatment and has been experimentally implemented for the cleanup of PCB-contaminated soil at the following three Superfund sites Wide Beach in Erie County, New York (1985) Re-Solve in Massachusetts (1987) and Sol Lynn in Texas (1988). The glycolate process has been used to successfully treat contaminant concentrations of PCBs from less than 2 ppm to reportedly as high as 45,000 ppm. Using this technology, Helland et al. (1995) investigated reductive dechlorination of carbon tetrachloride with elemental iron and found that the rate of dechlorination to chloroform and methylene chloride was a fast first-order process. 

Contamination of local marine sediment by toxic chemical pollutants has been relatively well documented. The marine sediment POPs inventory was compiled based primarily on data generated from a major consultancy study on local toxic substances pollution (EPD, 2003a), EPD routine and ad hoc marine monitoring programmes of 2003/2004 and study reports published by local academia (Zheng et al., 2000 Muller et al., 2002 Tam and Yao, 2002 Wong et al., 2001, 2005). With the exception of mirex and toxaphene, all other POPs pesticides were detected in the... 

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