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Showing papers in "Critical Reviews in Environmental Science and Technology in 2002"


Journal ArticleDOI
TL;DR: In this paper, the long-term behavior of landfills with respect to changes in oxidation-reduction status is discussed based on theory and model simulations, and it seems that the somewhere postulated enhanced release of accumulated heavy metals would not take place within the time frames of thousands of years.
Abstract: The major potential environmental impacts related to landfill leachate are pollution of groundwater and surface waters. Landfill leachate contains pollutants that can be categorized into four groups (dissolved organic matter, inorganic macrocomponents, heavy metals, and xenobiotic organic compounds). Existing data show high leachate concentrations of all components in the early acid phase due to strong decomposition and leaching. In the long methanogenic phase a more stable leachate, with lower concentrations and a low BOD/COD-ratio, is observed. Generally, very low concentrations of heavy metals are observed. In contrast, the concentration of ammonia does not decrease, and often constitutes a major long-term pollutant in leachate. A broad range of xenobiotic organic compounds is observed in landfill leachate. The long-term behavior of landfills with respect to changes in oxidation-reduction status is discussed based on theory and model simulations. It seems that the somewhere postulated enhanced release of accumulated heavy metals would not take place within the time frames of thousands of years. This is supported by a few laboratory investigations. The existing data and model evaluations indicate that the xenobiotic organic compounds in most cases do not constitute a major long-term problem. This may suggest that ammonia will be of most concern in the long run.

2,122 citations


Journal ArticleDOI
TL;DR: In this article, the authors discuss the fate of organophosphorus pesticides in the aquatic environment via processes such as adsorption, hydrolysis, oxidation, and photochemical degradation.
Abstract: Organophosphorus pesticides (OPs) have been widely used throughout the world since the decline in the use of organochlorine pesticides in the 1960s and 1970s. They are less persistent in the environment when compared with organochlorine pesticides and thus pose less long-term health risks to nontarget aquatic organisms and humans. However, in recent years several governmental agencies, including the USEPA, have started to reconsider the wide use of organophosphorus pesticides due to concern about their effects on the central nervous systems of humans, children in particular. This review discusses the fate of organophosphorus pesticides in the aquatic environment via processes such as adsorption, hydrolysis, oxidation, and photochemical degradation. Furthermore, the breakdown products of OPs are discussed, as new research has indicated that the products of degradation can be very harmful as well and because relatively little research has been carried out on comprehensive product identification. Recommended...

201 citations


Journal ArticleDOI
TL;DR: In this article, the authors showed that the addition of synthetic amino acids and reducing protein contents resulted in significant decreases in the N, P, odor, and dry matter (DM) weight of manure.
Abstract: High-density livestock facilities lead to a concentration of livestock wastes and subsequent leakage of pollutants into the environment, resulting in public concern about their effects. Nitrogen (N) and phosphorus (P) are the most harmful components of animal manure, but odor from the manure itself and the livestock facilities is also a problem. Improving the nutrient efficiency of the livestock helps to decrease excretion of these environmental contaminants. Pigs and chickens are the main animals used in studies to improve nutrient efficiency to reduce excretion of environmental contaminants. Addition of feed supplements and modifying feeding programs to improve nutrient efficiency can result in significant decreases in the N, P, odor, and dry matter (DM) weight of manure. Examples of these methods include the following. (1) The addition of synthetic amino acids and reducing protein contents resulted in N reductions of 10 to 27% in broilers, 18 to 35% in chicks and layers, 19 to 62% in pigs, and a 9 to 4...

155 citations


Journal ArticleDOI
TL;DR: In this paper, a state-of-the-art review of surface waters of Swedish and Norwegian lakes is presented, focusing on natural and anthropogenic sources, chemical properties and levels, and toxicity mechanisms of these metals to aquatic organisms.
Abstract: This article is a state-of-the-art review about such metals as Al, Fe, Mn, Cu, Zn, Cd, Pb, Cr, Ni, Hg, and As in surface waters. It focuses on natural and anthropogenic sources, chemical properties and levels, and toxicity mechanisms of these metals to aquatic organisms, primarily fish and invertebrates. Organisms living in almost anoxic, sulfide-rich evironments are not incorporated into this study. This information is then linked to a Nordic Lake Survey implemented in 1995 on major chemistry and metals in Scandinavian surface waters to scale the problems of metals in Swedish and Norwegian surface waters. Because many acidified Swedish and Norwegian lakes also are limed, we also assess the risk of remobilization of metals because these waters reacidify due to reduced liming activity. The concentrations and chemical properties of metals in lakes relative to the biological effect levels suggest that the potential risks associated to both current and potential reacidified status of limed waters decreases in...

106 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examine similarities in constraints to mass transfer of hydrophobic organic compounds (HOCs) between the aqueous and various organic phases in porous media at the grain scale.
Abstract: We examine similarities in constraints to mass transfer of hydrophobic organic compounds (HOCs) between the aqueous and various organic phases in porous media at the grain scale. Published research and data are reviewed regarding equilibrium coefficients and first-order rate constants for mass transfer of HOCs between water and natural organic matter present in various geosorbents (e.g., soils, sediments, and aquifer solids), and several oils (petroleum products, decane, and coal tar). We propose how these equilibrium and mass-transfer coefficients can be estimated by methods common to all organic phases. Equilibrium coefficients can be reliably estimated using Raoult's law. First-order rate constants obtained from extensive literature data appear to be dependent on aqueous-phase diffusion and duration of exposure (or contact). The aqueous diffusion domain may be either an interfacial film (for low viscosity oil ganglia) or a retarded immobile water zone (for geosorbents).

36 citations