Chemical Right-to-Know Initiative

Environmental Protection Agency, Chemical Right-to-Know Initiative (available at http //www.epagov/ chemrtk). 

A component of EPA s Chemical Right-to-Know Initiative, the Voluntary Children s Chemical Evaluation Program (VCCEP) was intended to encourage the development of information about the health effects, exposures and risks of industrial chemicals to children. While the VCCEP is a voluntary program that focuses on the development of data and assessments, as with the HPV program, EPA indicated that it would consider whether a test rule... 

In its Chemical Right-to-Know initiative, the EPA committed to review and report on what new testing may be needed to assess the special impact chemicals may have on children. 65 Fed. Reg. 81700,81701 (Dec. 26,2000). 

Another example is the Awareness and Preparedness for Emergencies at Local Level (APELL) program, also launched in 1988. APELL was originally based on the Community Awareness and Emergency Response (CAER) program, which later became part of the chemical industry s Responsible Care initiative. It includes elements of the EU Seveso Directive and the U.S. Right-to-Know initiative (UNEP, 1997). 

The lack of this basic toxicity information on most high volume chemicals is a serious issue for risk assessment, safeguarding children s health, expanding the publie s right-to-know, and promoting the pollution prevention ethic which are important EPA initiatives. 

In the absence of an enzyme, the reaction rate v is proportional to the concentration of substance A (top). The constant k is the rate constant of the uncatalyzed reaction. Like all catalysts, the enzyme E (total concentration [E]t) creates a new reaction pathway, initially, A is bound to E (partial reaction 1, left), if this reaction is in chemical equilibrium, then with the help of the law of mass action—and taking into account the fact that [E]t = [E] + [EA]—one can express the concentration [EA] of the enzyme-substrate complex as a function of [A] (left). The Michaelis constant lknow that kcat > k—in other words, enzyme-bound substrate reacts to B much faster than A alone (partial reaction 2, right), kcat. the enzyme s turnover number, corresponds to the number of substrate molecules converted by one enzyme molecule per second. Like the conversion A B, the formation of B from EA is a first-order reaction—i. e., V = k [EA] applies. When this equation is combined with the expression already derived for EA, the result is the Michaelis-Menten equation. 

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