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Background: The National Research Council (NRC) Committee on Improving Risk Analysis Approaches Used by the U.S. EPA (Environmental Protection Agency) recommended that low-dose risks be estimated in some situations using human variability distributions (HVDs). HVD modeling estimates log-normal distributions from data on pharmacokinetic and pharmacodynamic variables that affect individual sensitivities to the toxic response. These distributions are combined into an overall log-normal distribution for the threshold dose (dose below which there is no contribution to a toxic response) by assuming the variables act independently and multiplicatively. This distribution is centered at a point-of-departure dose that is usually estimated from animal data. The resulting log-normal distribution is used to quantify low-dose risk. Objective: We examined the implications of various assumptions in HVD modeling for estimating low-dose risk. Methods: The assumptions and data used in HVD modeling were subjected to rigorous scrutiny. Results: We found that the assumption that the variables affecting human sensitivity vary log normally is not scientifically defensible. Other distributions that are equally consistent with the data provide very different estimates of low-dose risk. HVD modeling can also involve an assumption that a threshold dose defined by dichotomizing a continuous apical response has a log-normal distribution. This assumption is shown to be incompatible (except under highly specialized conditions) with assuming that the continuous apical response itself is log normal. However, the two assumptions can lead to very different estimates of low-dose risk. The assumption in HVD modeling that the threshold dose can be expressed as a function of a product of independent variables lacks phenomenological support. We provide an example that shows that this assumption is generally invalid. Conclusion: In view of these problems, we recommend caution in the use of HVD modeling as a general approach to estimating low-dose risks from human exposures to toxic chemicals. [ABSTRACT FROM AUTHOR]

The Supreme Court's split decision in Rapanos v. United States left the lower courts with the question of whether to apply the plurality's restrictive test for determining which waters are protected under the Clean Water Act (CWA), or whether to use Justice Kennedy's more flexible, policy-based test. For those courts intending to follow Kennedy's concurrence, the parameters of his "significant nexus" test were far from explicit. In Baykeeper v. Cargill Salt Division the Ninth Circuit relinquished its first opportunity to apply the significant nexus test expansively in order to keep the CWA potent as a tool for environmental protection. The best remaining approach for litigants seeking to establish CWA coverage of non-navigable-in-fact waters that are not wetlands is to proceed under the theory that such waters are tributaries with a significant nexus to navigable waterways, pressing this language into service in the broadest array of hydrological scenarios possible. [ABSTRACT FROM AUTHOR]

The article presents information on the recommendations made by a committee of the National Research Council (NRC) to control chemical pollution in the environment. Of 34 recommendations advanced to aid the U.S. Environmental Protection Agency in improving its decision-making processes, 19 deal with the collection and dissemination of information. The report summary states that openness in decision making will improve the quality of the information used to make the decision and will facilitate implementation and acceptance of the decision.

The article reports on environmental sustainability in the twenty-first century as manifested in the motion picture "Who Killed the Electric Car?" This film underlines the introduction and death of the EV-1 electric car that General Motors developed and began marketing to Californians in 1996 to meet the requirements of the state's Zero Emission Vehicle mandate. The author noted the developments which transpired in previous years and the manner by which corporate managers view the risks and opportunities inherent in meeting society's growing need for answers to growing environmental problems.

The article focuses on the environmental health protection issues in New Zealand and compares the environemtal law in the country with that in the U.S. The Environmental Performance Index ranked New Zealand first out of 133 countries in the areas of health, biodiversity, energy, water, air, and natural resources, in an announcement at the annual meeting of the World Economic Forum in January 2006 in Davos, Switzerland. With 78.5/100 points, the U.S. ranked 28th. Demand for water for all purposes is increasing in New Zealand. The current pressures on freshwater ecosystems are less severe in New Zealand than those in many other industrialized countries. As the 1986 New Zealand Environment Act establishes the New Zealand Ministry for the Environment and its associated minister, it roughly corresponds to the 1969 U.S. National Environmental Policy Act.

The article reports on the findings of the study titled "Institutions for Effective Management of the Environment," conducted by the National Academy of Sciences study group composed of scientists and engineers, as well as economists and lawyers, in the U.S. It notes that the group recommends a program for effective management of the environment in dealing with environmental problems. The group further recommends that a comprehensive environmental monitoring program must be carried out by a new independent federal agency or one existing agency. They found out that effective monitoring of the environment must include development of appropriate environmental quality indexes.

This article reports that activists are criticizing a proposal by the U.S. Environmental Protection Agency (EPA) to speed up its regular review of air-quality standards. By law, EPA must revisit its National Ambient Air Quality Standards every 5 years. Staff scientists evaluate the latest research and propose ranges for new standards, which are then reviewed by the agency's Clean Air Scientific Advisory Committee. Because EPA regularly misses its deadline and gets sued, an internal EPA committee proposed several suggestions in for speeding up the process. EPA chief scientist George Gray said that the idea behind this proposal is not to have the policy drive the science.

The article informs that critics of revision to air pollution standards, proposed last month by the U.S. Environmental Protection Agency (EPA), say the new daily threshold will only marginally improve public health. In fact, an outside panel that made such a recommendation is not happy with EPA's decision. EPA Administrator Stephen Johnson did not answer that question during a 20 December teleconference announcing the standards but said he had thought long and hard about the data. Studies have shown that inhaling the small particles that make up soot, a widespread byproduct of combustion, harms health, although the mechanisms are not all clear. In 1997, the EPA first regulated fine particles measuring 2.5 micrometers or less. As part of a settlement in a suit brought by the American Lung Association, EPA was required to propose revised PM 2.5 rules by the end of 2005. Such a reduction could make a big difference in public health, scientists have found. The EPA models for nine major U.S. cities predict that the tightest daily and annual standards recommended by CASAC would cut the roughly 4700 deaths due each year to PM 2.5 in those cities by 48%.

Research budgets at the U.S. Environmental Protection Agency (EPA) would face a 4.3% cut, to $589 million, in a spending plan approved last week by the U.S. House of Representatives' appropriations committee. The cuts are part of an increasingly gloomy budget picture for science. The panel restored funding to EPA's extramural grants program, called Science to Achieve Results, bringing the program back to its fiscal year 2004 level of about $76.1 million, with an additional $9.5 million spent on graduate fellowships.