United States Environmental Protection Agency

About: United States Environmental Protection Agency is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Environmental exposure. The organization has 13873 authors who have published 26902 publications receiving 1191729 citations. The organization is also known as: EPA & Environmental Protection Agency.

Recovery of lotic communities and ecosystems from disturbance: a narrative review of case studies

Abstract: We present a narrative account of case studies of the recovery of flowing water systems from disturbance, focusing on the investigators' conclusions about recovery time and the factors contributing to recovery. We restrict our attention to case studies in which the recovery of some biological property of the system has been examined, excluding those that deal only with physical or chemical properties. Although natural processes and rates of recovery are emphasized, studies of reclamation or restoration of damaged ecosystems are included where they contribute to an understanding of recovery processes. For the majority of studies examined, the systems recovered quite rapidly. The most commonly cited reasons for short recovery times were: (1) life history characteristics that allowed rapid recolonization and repopulation of the affected areas, (2) the availability and accessibility of unaffected up-stream and downstream areas and internal refugia to serve as sources of organisms for repopulation, (3) the high flushing rates of lotic systems that allowed them to quickly dilute or replace polluted waters, and (4) the fact that lotic systems are naturally subjected to a variety of disturbances and the biota have evolved life history characteristics that favor flexibility or adaptability. In general, longer recovery times were observed in disturbances, such as channelization, that resulted in alterations to physical conditions. This review also indicates that much of our knowledge of recovery in lotic ecosystems is fragmented and uncoordinated. In addition to establishing the bounds of recovery time, our review identifies some research gaps that need to be filled.

Science, scientists, and policy advocacy.

Abstract: I am concerned that we scientists in conservation biology, ecology, natural resources, environmental science, and similar disciplines are collectively slipping into a morass that risks marginalizing the contribution of science to public policy. Advocating personal positions on ecological policy issues has become widely tolerated as acceptable professional behavior and is even encouraged by a substantial fraction of the scientific community (Marris 2006; Scott et al. 2007). Scientists are uniquely qualified to participate in public policy deliberations and they should, but advocating for their policy preferences is not appropriate. Despite an extensive debate in the literature on the proper role of science and scientists in policy deliberations, points of general agreement and specific differences often get lost amid the semantic confusion caused by inconsistent definitions for key words or concepts (Trudgill 2001). Table 1 provides the precise definitions I have used throughout this essay. Those of us who provide scientific information to decision makers and the public should strive to be more vigilant, precise, demanding, and rigorous in distinguishing between policy-neutral and policy-inculcated scientific information. Science is only one element of the complex deliberations over major ecological policy questions that take place in a democracy, but science is critical, and scientists can and do play an important role (Sarewitz 2004; Lackey 2006). My unequivocal overall view on the role of scientists in ecological policy and management is, first, that scientists should contribute to the policy process. This is not only the right thing to do, but we are also obligated to do so, especially if our work is funded by public resources. I do not hold with the notion that it is sufficient for scientists to publish their findings solely as scholarly papers. The assertion that scientists should be involved in providing

Tribromopyrrole, brominated acids, and other disinfection byproducts produced by disinfection of drinking water rich in bromide.

Abstract: Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comprehensive investigation of DBPs formed by chlorine dioxide under high bromide conditions. Drinking water from full-scale treatment plants in Israel was studied, along with source water (Sea of Galilee) treated under carefully controlled laboratory conditions. Select DBPs (trihalomethanes, haloacetic acids, aldehydes, chlorite, chlorate, and bromate) were quantified. Many of the DBPs identified have not been previously reported, and several of the identifications were confirmed through the analysis of authentic standards. Elevated bromide levels in the source water caused a significant shift in speciation to bromine-containing DBPs; bromoform and dibromoacetic acid were the dominant DBPs observed, with very few chlorine-containing c...