Chemical release statistics

Public concern about industrial chemical exposures might also be misguided. The EPA typically uses mathematical dispersion models to calculate human exposure to chemicals released into the air by major stationary sources like factories and power plants. There is little evidence that the models are predictive. In one experiment, a tracer gas was released from the Alaska pipeline terminus at Valdez. Actual exposure, as measured by personal exposure badges, was compared with the predictions of the EPA dispersion model. The statistical correlation between them was near zero (— 0.01), meaning the predictions were worthless (Wallace 1993, 137-38). 

Native starches are used as disintegrants, diluents, and wet binders. However, their poor flow and high lubricant sensitivity make them less favorable in direct compression. Different chemical, mechanical, and physical modifications of native starches have been used to improve both their direct compression and controlled-release properties (Sanghvi, 1993 van Aerde and Remon, 1988). Schinzinger and Schmidt (2005) used potato starch as an excipient and compared its granulating behavior with a-lactose-monohydrate and di-calcium phosphate anhydrous in a laboratory fluidized bed granulator using statistical methods. 

Each manufacturer of a packaging component sold to a drug product manufacturer should provide a description of the quality control measures used to maintain consistency in the physical and chemical characteristics of the component. These measures generally include release criteria (and test methods, if appropriate) and a description of the manufacturing procedure. If the release of the packaging component is based on statistical process control, a complete description of the process (including control criteria) and its validation should be provided. 

An in vitro release rate can reflect the combined effect of several physical and chemical parameters, including solubility and particle size of the active ingredient and rheological properties of the dosage form. In most cases, in vitro release rate is a useful test to assess product sameness between prechange and postchange products. However, there may be instances where it is not suitable for this purpose. In such cases, other physical and chemical tests to be used as measures of sameness should be proposed and discussed with the Agency. With any test, the metrics and statistical approaches to documentation of sameness in quality attributes should be considered. 

Canadian Health Measures Survey Beginning in 2006, Statistics Canada will initiate a national survey of 5,000 people to collect data on health status and biological measurements to assess exposures to environmental chemicals, including lead and mercury. The surveys are currently in development and collection of data is expected to begin in the fall of 2006, with results released in 2009 (Statistics Canada 2006). 

The principal source of chlorobenzene in water is release from chemical manufacturing facilities. Dow Chemical Company estimated that 0.1% of its annual production enters waters (EPA 1980a). Perry et al. (1979) found chlorobenzene in 6/63 industrial effluent in concentrations up to 100 pg/L. Based on 1,338 samples collected from about 1980 to 1983, the medium concentration of chlorobenzene in waste effluent was < 3 ppb and was detected in 54 samples. The total amount released to the environment was not reported (Staples et al. 1985). Chlorobenzene has been detected in both surface and groundwater samples at hazardous waste sites. Data from the Contract Laboratory Program (CLP) Statistical Database indicate that chlorobenzene occurred in surface water at 13 sites at a geometric mean concentration of 17 ppb in positive samples and in... 

The pollutant release and transfer register (PRTR) system is one in which enterprises voluntarily calculate the amounts of specific chemical substances released into the environment that are potentially toxic to human health and/or the ecosystem, and the amounts of such substances contained in waste and transferred out of the firm s area, and report these amounts to their local governments. The national government adds up the released or transferred amounts of such a substance based on the reports from the enterprises, statistical data, etc. and publicly announces the results. 

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